sys/dev/hwpmc/hwpmc_mod.c

   1 /*-
   2  * Copyright (c) 2003-2008 Joseph Koshy
   3  * Copyright (c) 2007 The FreeBSD Foundation
   4  * All rights reserved.
   5  *
   6  * Portions of this software were developed by A. Joseph Koshy under
   7  * sponsorship from the FreeBSD Foundation and Google, Inc.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  *
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD$");
  34
  35 #include <sys/param.h>
  36 #include <sys/eventhandler.h>
  37 #include <sys/jail.h>
  38 #include <sys/kernel.h>
  39 #include <sys/kthread.h>
  40 #include <sys/limits.h>
  41 #include <sys/lock.h>
  42 #include <sys/malloc.h>
  43 #include <sys/module.h>
  44 #include <sys/mount.h>
  45 #include <sys/mutex.h>
  46 #include <sys/pmc.h>
  47 #include <sys/pmckern.h>
  48 #include <sys/pmclog.h>
  49 #include <sys/priv.h>
  50 #include <sys/proc.h>
  51 #include <sys/queue.h>
  52 #include <sys/resourcevar.h>
  53 #include <sys/rwlock.h>
  54 #include <sys/sched.h>
  55 #include <sys/signalvar.h>
  56 #include <sys/smp.h>
  57 #include <sys/sx.h>
  58 #include <sys/sysctl.h>
  59 #include <sys/sysent.h>
  60 #include <sys/systm.h>
  61 #include <sys/vnode.h>
  62
  63 #include <sys/linker.h>         /* needs to be after <sys/malloc.h> */
  64
  65 #include <machine/atomic.h>
  66 #include <machine/md_var.h>
  67
  68 #include <vm/vm.h>
  69 #include <vm/vm_extern.h>
  70 #include <vm/pmap.h>
  71 #include <vm/vm_map.h>
  72 #include <vm/vm_object.h>
  73
  74 #include "hwpmc_soft.h"
  75
  76 /*
  77  * Types
  78  */
  79
  80 enum pmc_flags {
  81         PMC_FLAG_NONE     = 0x00, /* do nothing */
  82         PMC_FLAG_REMOVE   = 0x01, /* atomically remove entry from hash */
  83         PMC_FLAG_ALLOCATE = 0x02, /* add entry to hash if not found */
  84 };
  85
  86 /*
  87  * The offset in sysent where the syscall is allocated.
  88  */
  89
  90 static int pmc_syscall_num = NO_SYSCALL;
  91 struct pmc_cpu          **pmc_pcpu;      /* per-cpu state */
  92 pmc_value_t             *pmc_pcpu_saved; /* saved PMC values: CSW handling */
  93
  94 #define PMC_PCPU_SAVED(C,R)     pmc_pcpu_saved[(R) + md->pmd_npmc*(C)]
  95
  96 struct mtx_pool         *pmc_mtxpool;
  97 static int              *pmc_pmcdisp;    /* PMC row dispositions */
  98
  99 #define PMC_ROW_DISP_IS_FREE(R)         (pmc_pmcdisp[(R)] == 0)
 100 #define PMC_ROW_DISP_IS_THREAD(R)       (pmc_pmcdisp[(R)] > 0)
 101 #define PMC_ROW_DISP_IS_STANDALONE(R)   (pmc_pmcdisp[(R)] < 0)
 102
 103 #define PMC_MARK_ROW_FREE(R) do {                                         \
 104         pmc_pmcdisp[(R)] = 0;                                             \
 105 } while (0)
 106
 107 #define PMC_MARK_ROW_STANDALONE(R) do {                                   \
 108         KASSERT(pmc_pmcdisp[(R)] <= 0, ("[pmc,%d] row disposition error", \
 109                     __LINE__));                                           \
 110         atomic_add_int(&pmc_pmcdisp[(R)], -1);                            \
 111         KASSERT(pmc_pmcdisp[(R)] >= (-pmc_cpu_max_active()),              \
 112                 ("[pmc,%d] row disposition error", __LINE__));            \
 113 } while (0)
 114
 115 #define PMC_UNMARK_ROW_STANDALONE(R) do {                                 \
 116         atomic_add_int(&pmc_pmcdisp[(R)], 1);                             \
 117         KASSERT(pmc_pmcdisp[(R)] <= 0, ("[pmc,%d] row disposition error", \
 118                     __LINE__));                                           \
 119 } while (0)
 120
 121 #define PMC_MARK_ROW_THREAD(R) do {                                       \
 122         KASSERT(pmc_pmcdisp[(R)] >= 0, ("[pmc,%d] row disposition error", \
 123                     __LINE__));                                           \
 124         atomic_add_int(&pmc_pmcdisp[(R)], 1);                             \
 125 } while (0)
 126
 127 #define PMC_UNMARK_ROW_THREAD(R) do {                                     \
 128         atomic_add_int(&pmc_pmcdisp[(R)], -1);                            \
 129         KASSERT(pmc_pmcdisp[(R)] >= 0, ("[pmc,%d] row disposition error", \
 130                     __LINE__));                                           \
 131 } while (0)
 132
 133
 134 /* various event handlers */
 135 static eventhandler_tag pmc_exit_tag, pmc_fork_tag, pmc_kld_load_tag,
 136     pmc_kld_unload_tag;
 137
 138 /* Module statistics */
 139 struct pmc_op_getdriverstats pmc_stats;
 140
 141 /* Machine/processor dependent operations */
 142 static struct pmc_mdep  *md;
 143
 144 /*
 145  * Hash tables mapping owner processes and target threads to PMCs.
 146  */
 147
 148 struct mtx pmc_processhash_mtx;         /* spin mutex */
 149 static u_long pmc_processhashmask;
 150 static LIST_HEAD(pmc_processhash, pmc_process)  *pmc_processhash;
 151
 152 /*
 153  * Hash table of PMC owner descriptors.  This table is protected by
 154  * the shared PMC "sx" lock.
 155  */
 156
 157 static u_long pmc_ownerhashmask;
 158 static LIST_HEAD(pmc_ownerhash, pmc_owner)      *pmc_ownerhash;
 159
 160 /*
 161  * List of PMC owners with system-wide sampling PMCs.
 162  */
 163
 164 static LIST_HEAD(, pmc_owner)                   pmc_ss_owners;
 165
 166
 167 /*
 168  * A map of row indices to classdep structures.
 169  */
 170 static struct pmc_classdep **pmc_rowindex_to_classdep;
 171
 172 /*
 173  * Prototypes
 174  */
 175
 176 #ifdef  DEBUG
 177 static int      pmc_debugflags_sysctl_handler(SYSCTL_HANDLER_ARGS);
 178 static int      pmc_debugflags_parse(char *newstr, char *fence);
 179 #endif
 180
 181 static int      load(struct module *module, int cmd, void *arg);
 182 static int      pmc_attach_process(struct proc *p, struct pmc *pm);
 183 static struct pmc *pmc_allocate_pmc_descriptor(void);
 184 static struct pmc_owner *pmc_allocate_owner_descriptor(struct proc *p);
 185 static int      pmc_attach_one_process(struct proc *p, struct pmc *pm);
 186 static int      pmc_can_allocate_rowindex(struct proc *p, unsigned int ri,
 187     int cpu);
 188 static int      pmc_can_attach(struct pmc *pm, struct proc *p);
 189 static void     pmc_capture_user_callchain(int cpu, int soft, struct trapframe *tf);
 190 static void     pmc_cleanup(void);
 191 static int      pmc_detach_process(struct proc *p, struct pmc *pm);
 192 static int      pmc_detach_one_process(struct proc *p, struct pmc *pm,
 193     int flags);
 194 static void     pmc_destroy_owner_descriptor(struct pmc_owner *po);
 195 static struct pmc_owner *pmc_find_owner_descriptor(struct proc *p);
 196 static int      pmc_find_pmc(pmc_id_t pmcid, struct pmc **pm);
 197 static struct pmc *pmc_find_pmc_descriptor_in_process(struct pmc_owner *po,
 198     pmc_id_t pmc);
 199 static struct pmc_process *pmc_find_process_descriptor(struct proc *p,
 200     uint32_t mode);
 201 static void     pmc_force_context_switch(void);
 202 static void     pmc_link_target_process(struct pmc *pm,
 203     struct pmc_process *pp);
 204 static void     pmc_log_all_process_mappings(struct pmc_owner *po);
 205 static void     pmc_log_kernel_mappings(struct pmc *pm);
 206 static void     pmc_log_process_mappings(struct pmc_owner *po, struct proc *p);
 207 static void     pmc_maybe_remove_owner(struct pmc_owner *po);
 208 static void     pmc_process_csw_in(struct thread *td);
 209 static void     pmc_process_csw_out(struct thread *td);
 210 static void     pmc_process_exit(void *arg, struct proc *p);
 211 static void     pmc_process_fork(void *arg, struct proc *p1,
 212     struct proc *p2, int n);
 213 static void     pmc_process_samples(int cpu, int soft);
 214 static void     pmc_release_pmc_descriptor(struct pmc *pmc);
 215 static void     pmc_remove_owner(struct pmc_owner *po);
 216 static void     pmc_remove_process_descriptor(struct pmc_process *pp);
 217 static void     pmc_restore_cpu_binding(struct pmc_binding *pb);
 218 static void     pmc_save_cpu_binding(struct pmc_binding *pb);
 219 static void     pmc_select_cpu(int cpu);
 220 static int      pmc_start(struct pmc *pm);
 221 static int      pmc_stop(struct pmc *pm);
 222 static int      pmc_syscall_handler(struct thread *td, void *syscall_args);
 223 static void     pmc_unlink_target_process(struct pmc *pmc,
 224     struct pmc_process *pp);
 225 static int generic_switch_in(struct pmc_cpu *pc, struct pmc_process *pp);
 226 static int generic_switch_out(struct pmc_cpu *pc, struct pmc_process *pp);
 227 static struct pmc_mdep *pmc_generic_cpu_initialize(void);
 228 static void pmc_generic_cpu_finalize(struct pmc_mdep *md);
 229
 230 /*
 231  * Kernel tunables and sysctl(8) interface.
 232  */
 233
 234 SYSCTL_DECL(_kern_hwpmc);
 235
 236 static int pmc_callchaindepth = PMC_CALLCHAIN_DEPTH;
 237 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "callchaindepth", &pmc_callchaindepth);
 238 SYSCTL_INT(_kern_hwpmc, OID_AUTO, callchaindepth, CTLFLAG_TUN|CTLFLAG_RD,
 239     &pmc_callchaindepth, 0, "depth of call chain records");
 240
 241 #ifdef  DEBUG
 242 struct pmc_debugflags pmc_debugflags = PMC_DEBUG_DEFAULT_FLAGS;
 243 char    pmc_debugstr[PMC_DEBUG_STRSIZE];
 244 TUNABLE_STR(PMC_SYSCTL_NAME_PREFIX "debugflags", pmc_debugstr,
 245     sizeof(pmc_debugstr));
 246 SYSCTL_PROC(_kern_hwpmc, OID_AUTO, debugflags,
 247     CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_TUN,
 248     0, 0, pmc_debugflags_sysctl_handler, "A", "debug flags");
 249 #endif
 250
 251 /*
 252  * kern.hwpmc.hashrows -- determines the number of rows in the
 253  * of the hash table used to look up threads
 254  */
 255
 256 static int pmc_hashsize = PMC_HASH_SIZE;
 257 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "hashsize", &pmc_hashsize);
 258 SYSCTL_INT(_kern_hwpmc, OID_AUTO, hashsize, CTLFLAG_TUN|CTLFLAG_RD,
 259     &pmc_hashsize, 0, "rows in hash tables");
 260
 261 /*
 262  * kern.hwpmc.nsamples --- number of PC samples/callchain stacks per CPU
 263  */
 264
 265 static int pmc_nsamples = PMC_NSAMPLES;
 266 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "nsamples", &pmc_nsamples);
 267 SYSCTL_INT(_kern_hwpmc, OID_AUTO, nsamples, CTLFLAG_TUN|CTLFLAG_RD,
 268     &pmc_nsamples, 0, "number of PC samples per CPU");
 269
 270
 271 /*
 272  * kern.hwpmc.mtxpoolsize -- number of mutexes in the mutex pool.
 273  */
 274
 275 static int pmc_mtxpool_size = PMC_MTXPOOL_SIZE;
 276 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "mtxpoolsize", &pmc_mtxpool_size);
 277 SYSCTL_INT(_kern_hwpmc, OID_AUTO, mtxpoolsize, CTLFLAG_TUN|CTLFLAG_RD,
 278     &pmc_mtxpool_size, 0, "size of spin mutex pool");
 279
 280
 281 /*
 282  * security.bsd.unprivileged_syspmcs -- allow non-root processes to
 283  * allocate system-wide PMCs.
 284  *
 285  * Allowing unprivileged processes to allocate system PMCs is convenient
 286  * if system-wide measurements need to be taken concurrently with other
 287  * per-process measurements.  This feature is turned off by default.
 288  */
 289
 290 static int pmc_unprivileged_syspmcs = 0;
 291 TUNABLE_INT("security.bsd.unprivileged_syspmcs", &pmc_unprivileged_syspmcs);
 292 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_syspmcs, CTLFLAG_RW,
 293     &pmc_unprivileged_syspmcs, 0,
 294     "allow unprivileged process to allocate system PMCs");
 295
 296 /*
 297  * Hash function.  Discard the lower 2 bits of the pointer since
 298  * these are always zero for our uses.  The hash multiplier is
 299  * round((2^LONG_BIT) * ((sqrt(5)-1)/2)).
 300  */
 301
 302 #if     LONG_BIT == 64
 303 #define _PMC_HM         11400714819323198486u
 304 #elif   LONG_BIT == 32
 305 #define _PMC_HM         2654435769u
 306 #else
 307 #error  Must know the size of 'long' to compile
 308 #endif
 309
 310 #define PMC_HASH_PTR(P,M)       ((((unsigned long) (P) >> 2) * _PMC_HM) & (M))
 311
 312 /*
 313  * Syscall structures
 314  */
 315
 316 /* The `sysent' for the new syscall */
 317 static struct sysent pmc_sysent = {
 318         2,                      /* sy_narg */
 319         pmc_syscall_handler     /* sy_call */
 320 };
 321
 322 static struct syscall_module_data pmc_syscall_mod = {
 323         load,
 324         NULL,
 325         &pmc_syscall_num,
 326         &pmc_sysent,
 327         { 0, NULL }
 328 };
 329
 330 static moduledata_t pmc_mod = {
 331         PMC_MODULE_NAME,
 332         syscall_module_handler,
 333         &pmc_syscall_mod
 334 };
 335
 336 DECLARE_MODULE(pmc, pmc_mod, SI_SUB_SMP, SI_ORDER_ANY);
 337 MODULE_VERSION(pmc, PMC_VERSION);
 338
 339 #ifdef  DEBUG
 340 enum pmc_dbgparse_state {
 341         PMCDS_WS,               /* in whitespace */
 342         PMCDS_MAJOR,            /* seen a major keyword */
 343         PMCDS_MINOR
 344 };
 345
 346 static int
 347 pmc_debugflags_parse(char *newstr, char *fence)
 348 {
 349         char c, *p, *q;
 350         struct pmc_debugflags *tmpflags;
 351         int error, found, *newbits, tmp;
 352         size_t kwlen;
 353
 354         tmpflags = malloc(sizeof(*tmpflags), M_PMC, M_WAITOK|M_ZERO);
 355
 356         p = newstr;
 357         error = 0;
 358
 359         for (; p < fence && (c = *p); p++) {
 360
 361                 /* skip white space */
 362                 if (c == ' ' || c == '\t')
 363                         continue;
 364
 365                 /* look for a keyword followed by "=" */
 366                 for (q = p; p < fence && (c = *p) && c != '='; p++)
 367                         ;
 368                 if (c != '=') {
 369                         error = EINVAL;
 370                         goto done;
 371                 }
 372
 373                 kwlen = p - q;
 374                 newbits = NULL;
 375
 376                 /* lookup flag group name */
 377 #define DBG_SET_FLAG_MAJ(S,F)                                           \
 378                 if (kwlen == sizeof(S)-1 && strncmp(q, S, kwlen) == 0)  \
 379                         newbits = &tmpflags->pdb_ ## F;
 380
 381                 DBG_SET_FLAG_MAJ("cpu",         CPU);
 382                 DBG_SET_FLAG_MAJ("csw",         CSW);
 383                 DBG_SET_FLAG_MAJ("logging",     LOG);
 384                 DBG_SET_FLAG_MAJ("module",      MOD);
 385                 DBG_SET_FLAG_MAJ("md",          MDP);
 386                 DBG_SET_FLAG_MAJ("owner",       OWN);
 387                 DBG_SET_FLAG_MAJ("pmc",         PMC);
 388                 DBG_SET_FLAG_MAJ("process",     PRC);
 389                 DBG_SET_FLAG_MAJ("sampling",    SAM);
 390
 391                 if (newbits == NULL) {
 392                         error = EINVAL;
 393                         goto done;
 394                 }
 395
 396                 p++;            /* skip the '=' */
 397
 398                 /* Now parse the individual flags */
 399                 tmp = 0;
 400         newflag:
 401                 for (q = p; p < fence && (c = *p); p++)
 402                         if (c == ' ' || c == '\t' || c == ',')
 403                                 break;
 404
 405                 /* p == fence or c == ws or c == "," or c == 0 */
 406
 407                 if ((kwlen = p - q) == 0) {
 408                         *newbits = tmp;
 409                         continue;
 410                 }
 411
 412                 found = 0;
 413 #define DBG_SET_FLAG_MIN(S,F)                                           \
 414                 if (kwlen == sizeof(S)-1 && strncmp(q, S, kwlen) == 0)  \
 415                         tmp |= found = (1 << PMC_DEBUG_MIN_ ## F)
 416
 417                 /* a '*' denotes all possible flags in the group */
 418                 if (kwlen == 1 && *q == '*')
 419                         tmp = found = ~0;
 420                 /* look for individual flag names */
 421                 DBG_SET_FLAG_MIN("allocaterow", ALR);
 422                 DBG_SET_FLAG_MIN("allocate",    ALL);
 423                 DBG_SET_FLAG_MIN("attach",      ATT);
 424                 DBG_SET_FLAG_MIN("bind",        BND);
 425                 DBG_SET_FLAG_MIN("config",      CFG);
 426                 DBG_SET_FLAG_MIN("exec",        EXC);
 427                 DBG_SET_FLAG_MIN("exit",        EXT);
 428                 DBG_SET_FLAG_MIN("find",        FND);
 429                 DBG_SET_FLAG_MIN("flush",       FLS);
 430                 DBG_SET_FLAG_MIN("fork",        FRK);
 431                 DBG_SET_FLAG_MIN("getbuf",      GTB);
 432                 DBG_SET_FLAG_MIN("hook",        PMH);
 433                 DBG_SET_FLAG_MIN("init",        INI);
 434                 DBG_SET_FLAG_MIN("intr",        INT);
 435                 DBG_SET_FLAG_MIN("linktarget",  TLK);
 436                 DBG_SET_FLAG_MIN("mayberemove", OMR);
 437                 DBG_SET_FLAG_MIN("ops",         OPS);
 438                 DBG_SET_FLAG_MIN("read",        REA);
 439                 DBG_SET_FLAG_MIN("register",    REG);
 440                 DBG_SET_FLAG_MIN("release",     REL);
 441                 DBG_SET_FLAG_MIN("remove",      ORM);
 442                 DBG_SET_FLAG_MIN("sample",      SAM);
 443                 DBG_SET_FLAG_MIN("scheduleio",  SIO);
 444                 DBG_SET_FLAG_MIN("select",      SEL);
 445                 DBG_SET_FLAG_MIN("signal",      SIG);
 446                 DBG_SET_FLAG_MIN("swi",         SWI);
 447                 DBG_SET_FLAG_MIN("swo",         SWO);
 448                 DBG_SET_FLAG_MIN("start",       STA);
 449                 DBG_SET_FLAG_MIN("stop",        STO);
 450                 DBG_SET_FLAG_MIN("syscall",     PMS);
 451                 DBG_SET_FLAG_MIN("unlinktarget", TUL);
 452                 DBG_SET_FLAG_MIN("write",       WRI);
 453                 if (found == 0) {
 454                         /* unrecognized flag name */
 455                         error = EINVAL;
 456                         goto done;
 457                 }
 458
 459                 if (c == 0 || c == ' ' || c == '\t') {  /* end of flag group */
 460                         *newbits = tmp;
 461                         continue;
 462                 }
 463
 464                 p++;
 465                 goto newflag;
 466         }
 467
 468         /* save the new flag set */
 469         bcopy(tmpflags, &pmc_debugflags, sizeof(pmc_debugflags));
 470
 471  done:
 472         free(tmpflags, M_PMC);
 473         return error;
 474 }
 475
 476 static int
 477 pmc_debugflags_sysctl_handler(SYSCTL_HANDLER_ARGS)
 478 {
 479         char *fence, *newstr;
 480         int error;
 481         unsigned int n;
 482
 483         (void) arg1; (void) arg2; /* unused parameters */
 484
 485         n = sizeof(pmc_debugstr);
 486         newstr = malloc(n, M_PMC, M_WAITOK|M_ZERO);
 487         (void) strlcpy(newstr, pmc_debugstr, n);
 488
 489         error = sysctl_handle_string(oidp, newstr, n, req);
 490
 491         /* if there is a new string, parse and copy it */
 492         if (error == 0 && req->newptr != NULL) {
 493                 fence = newstr + (n < req->newlen ? n : req->newlen + 1);
 494                 if ((error = pmc_debugflags_parse(newstr, fence)) == 0)
 495                         (void) strlcpy(pmc_debugstr, newstr,
 496                             sizeof(pmc_debugstr));
 497         }
 498
 499         free(newstr, M_PMC);
 500
 501         return error;
 502 }
 503 #endif
 504
 505 /*
 506  * Map a row index to a classdep structure and return the adjusted row
 507  * index for the PMC class index.
 508  */
 509 static struct pmc_classdep *
 510 pmc_ri_to_classdep(struct pmc_mdep *md, int ri, int *adjri)
 511 {
 512         struct pmc_classdep *pcd;
 513
 514         (void) md;
 515
 516         KASSERT(ri >= 0 && ri < md->pmd_npmc,
 517             ("[pmc,%d] illegal row-index %d", __LINE__, ri));
 518
 519         pcd = pmc_rowindex_to_classdep[ri];
 520
 521         KASSERT(pcd != NULL,
 522             ("[pmc,%d] ri %d null pcd", __LINE__, ri));
 523
 524         *adjri = ri - pcd->pcd_ri;
 525
 526         KASSERT(*adjri >= 0 && *adjri < pcd->pcd_num,
 527             ("[pmc,%d] adjusted row-index %d", __LINE__, *adjri));
 528
 529         return (pcd);
 530 }
 531
 532 /*
 533  * Concurrency Control
 534  *
 535  * The driver manages the following data structures:
 536  *
 537  *   - target process descriptors, one per target process
 538  *   - owner process descriptors (and attached lists), one per owner process
 539  *   - lookup hash tables for owner and target processes
 540  *   - PMC descriptors (and attached lists)
 541  *   - per-cpu hardware state
 542  *   - the 'hook' variable through which the kernel calls into
 543  *     this module
 544  *   - the machine hardware state (managed by the MD layer)
 545  *
 546  * These data structures are accessed from:
 547  *
 548  * - thread context-switch code
 549  * - interrupt handlers (possibly on multiple cpus)
 550  * - kernel threads on multiple cpus running on behalf of user
 551  *   processes doing system calls
 552  * - this driver's private kernel threads
 553  *
 554  * = Locks and Locking strategy =
 555  *
 556  * The driver uses four locking strategies for its operation:
 557  *
 558  * - The global SX lock "pmc_sx" is used to protect internal
 559  *   data structures.
 560  *
 561  *   Calls into the module by syscall() start with this lock being
 562  *   held in exclusive mode.  Depending on the requested operation,
 563  *   the lock may be downgraded to 'shared' mode to allow more
 564  *   concurrent readers into the module.  Calls into the module from
 565  *   other parts of the kernel acquire the lock in shared mode.
 566  *
 567  *   This SX lock is held in exclusive mode for any operations that
 568  *   modify the linkages between the driver's internal data structures.
 569  *
 570  *   The 'pmc_hook' function pointer is also protected by this lock.
 571  *   It is only examined with the sx lock held in exclusive mode.  The
 572  *   kernel module is allowed to be unloaded only with the sx lock held
 573  *   in exclusive mode.  In normal syscall handling, after acquiring the
 574  *   pmc_sx lock we first check that 'pmc_hook' is non-null before
 575  *   proceeding.  This prevents races between the thread unloading the module
 576  *   and other threads seeking to use the module.
 577  *
 578  * - Lookups of target process structures and owner process structures
 579  *   cannot use the global "pmc_sx" SX lock because these lookups need
 580  *   to happen during context switches and in other critical sections
 581  *   where sleeping is not allowed.  We protect these lookup tables
 582  *   with their own private spin-mutexes, "pmc_processhash_mtx" and
 583  *   "pmc_ownerhash_mtx".
 584  *
 585  * - Interrupt handlers work in a lock free manner.  At interrupt
 586  *   time, handlers look at the PMC pointer (phw->phw_pmc) configured
 587  *   when the PMC was started.  If this pointer is NULL, the interrupt
 588  *   is ignored after updating driver statistics.  We ensure that this
 589  *   pointer is set (using an atomic operation if necessary) before the
 590  *   PMC hardware is started.  Conversely, this pointer is unset atomically
 591  *   only after the PMC hardware is stopped.
 592  *
 593  *   We ensure that everything needed for the operation of an
 594  *   interrupt handler is available without it needing to acquire any
 595  *   locks.  We also ensure that a PMC's software state is destroyed only
 596  *   after the PMC is taken off hardware (on all CPUs).
 597  *
 598  * - Context-switch handling with process-private PMCs needs more
 599  *   care.
 600  *
 601  *   A given process may be the target of multiple PMCs.  For example,
 602  *   PMCATTACH and PMCDETACH may be requested by a process on one CPU
 603  *   while the target process is running on another.  A PMC could also
 604  *   be getting released because its owner is exiting.  We tackle
 605  *   these situations in the following manner:
 606  *
 607  *   - each target process structure 'pmc_process' has an array
 608  *     of 'struct pmc *' pointers, one for each hardware PMC.
 609  *
 610  *   - At context switch IN time, each "target" PMC in RUNNING state
 611  *     gets started on hardware and a pointer to each PMC is copied into
 612  *     the per-cpu phw array.  The 'runcount' for the PMC is
 613  *     incremented.
 614  *
 615  *   - At context switch OUT time, all process-virtual PMCs are stopped
 616  *     on hardware.  The saved value is added to the PMCs value field
 617  *     only if the PMC is in a non-deleted state (the PMCs state could
 618  *     have changed during the current time slice).
 619  *
 620  *     Note that since in-between a switch IN on a processor and a switch
 621  *     OUT, the PMC could have been released on another CPU.  Therefore
 622  *     context switch OUT always looks at the hardware state to turn
 623  *     OFF PMCs and will update a PMC's saved value only if reachable
 624  *     from the target process record.
 625  *
 626  *   - OP PMCRELEASE could be called on a PMC at any time (the PMC could
 627  *     be attached to many processes at the time of the call and could
 628  *     be active on multiple CPUs).
 629  *
 630  *     We prevent further scheduling of the PMC by marking it as in
 631  *     state 'DELETED'.  If the runcount of the PMC is non-zero then
 632  *     this PMC is currently running on a CPU somewhere.  The thread
 633  *     doing the PMCRELEASE operation waits by repeatedly doing a
 634  *     pause() till the runcount comes to zero.
 635  *
 636  * The contents of a PMC descriptor (struct pmc) are protected using
 637  * a spin-mutex.  In order to save space, we use a mutex pool.
 638  *
 639  * In terms of lock types used by witness(4), we use:
 640  * - Type "pmc-sx", used by the global SX lock.
 641  * - Type "pmc-sleep", for sleep mutexes used by logger threads.
 642  * - Type "pmc-per-proc", for protecting PMC owner descriptors.
 643  * - Type "pmc-leaf", used for all other spin mutexes.
 644  */
 645
 646 /*
 647  * save the cpu binding of the current kthread
 648  */
 649
 650 static void
 651 pmc_save_cpu_binding(struct pmc_binding *pb)
 652 {
 653         PMCDBG(CPU,BND,2, "%s", "save-cpu");
 654         thread_lock(curthread);
 655         pb->pb_bound = sched_is_bound(curthread);
 656         pb->pb_cpu   = curthread->td_oncpu;
 657         thread_unlock(curthread);
 658         PMCDBG(CPU,BND,2, "save-cpu cpu=%d", pb->pb_cpu);
 659 }
 660
 661 /*
 662  * restore the cpu binding of the current thread
 663  */
 664
 665 static void
 666 pmc_restore_cpu_binding(struct pmc_binding *pb)
 667 {
 668         PMCDBG(CPU,BND,2, "restore-cpu curcpu=%d restore=%d",
 669             curthread->td_oncpu, pb->pb_cpu);
 670         thread_lock(curthread);
 671         if (pb->pb_bound)
 672                 sched_bind(curthread, pb->pb_cpu);
 673         else
 674                 sched_unbind(curthread);
 675         thread_unlock(curthread);
 676         PMCDBG(CPU,BND,2, "%s", "restore-cpu done");
 677 }
 678
 679 /*
 680  * move execution over the specified cpu and bind it there.
 681  */
 682
 683 static void
 684 pmc_select_cpu(int cpu)
 685 {
 686         KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 687             ("[pmc,%d] bad cpu number %d", __LINE__, cpu));
 688
 689         /* Never move to an inactive CPU. */
 690         KASSERT(pmc_cpu_is_active(cpu), ("[pmc,%d] selecting inactive "
 691             "CPU %d", __LINE__, cpu));
 692
 693         PMCDBG(CPU,SEL,2, "select-cpu cpu=%d", cpu);
 694         thread_lock(curthread);
 695         sched_bind(curthread, cpu);
 696         thread_unlock(curthread);
 697
 698         KASSERT(curthread->td_oncpu == cpu,
 699             ("[pmc,%d] CPU not bound [cpu=%d, curr=%d]", __LINE__,
 700                 cpu, curthread->td_oncpu));
 701
 702         PMCDBG(CPU,SEL,2, "select-cpu cpu=%d ok", cpu);
 703 }
 704
 705 /*
 706  * Force a context switch.
 707  *
 708  * We do this by pause'ing for 1 tick -- invoking mi_switch() is not
 709  * guaranteed to force a context switch.
 710  */
 711
 712 static void
 713 pmc_force_context_switch(void)
 714 {
 715
 716         pause("pmcctx", 1);
 717 }
 718
 719 /*
 720  * Get the file name for an executable.  This is a simple wrapper
 721  * around vn_fullpath(9).
 722  */
 723
 724 static void
 725 pmc_getfilename(struct vnode *v, char **fullpath, char **freepath)
 726 {
 727
 728         *fullpath = "unknown";
 729         *freepath = NULL;
 730         vn_fullpath(curthread, v, fullpath, freepath);
 731 }
 732
 733 /*
 734  * remove an process owning PMCs
 735  */
 736
 737 void
 738 pmc_remove_owner(struct pmc_owner *po)
 739 {
 740         struct pmc *pm, *tmp;
 741
 742         sx_assert(&pmc_sx, SX_XLOCKED);
 743
 744         PMCDBG(OWN,ORM,1, "remove-owner po=%p", po);
 745
 746         /* Remove descriptor from the owner hash table */
 747         LIST_REMOVE(po, po_next);
 748
 749         /* release all owned PMC descriptors */
 750         LIST_FOREACH_SAFE(pm, &po->po_pmcs, pm_next, tmp) {
 751                 PMCDBG(OWN,ORM,2, "pmc=%p", pm);
 752                 KASSERT(pm->pm_owner == po,
 753                     ("[pmc,%d] owner %p != po %p", __LINE__, pm->pm_owner, po));
 754
 755                 pmc_release_pmc_descriptor(pm); /* will unlink from the list */
 756         }
 757
 758         KASSERT(po->po_sscount == 0,
 759             ("[pmc,%d] SS count not zero", __LINE__));
 760         KASSERT(LIST_EMPTY(&po->po_pmcs),
 761             ("[pmc,%d] PMC list not empty", __LINE__));
 762
 763         /* de-configure the log file if present */
 764         if (po->po_flags & PMC_PO_OWNS_LOGFILE)
 765                 pmclog_deconfigure_log(po);
 766 }
 767
 768 /*
 769  * remove an owner process record if all conditions are met.
 770  */
 771
 772 static void
 773 pmc_maybe_remove_owner(struct pmc_owner *po)
 774 {
 775
 776         PMCDBG(OWN,OMR,1, "maybe-remove-owner po=%p", po);
 777
 778         /*
 779          * Remove owner record if
 780          * - this process does not own any PMCs
 781          * - this process has not allocated a system-wide sampling buffer
 782          */
 783
 784         if (LIST_EMPTY(&po->po_pmcs) &&
 785             ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)) {
 786                 pmc_remove_owner(po);
 787                 pmc_destroy_owner_descriptor(po);
 788         }
 789 }
 790
 791 /*
 792  * Add an association between a target process and a PMC.
 793  */
 794
 795 static void
 796 pmc_link_target_process(struct pmc *pm, struct pmc_process *pp)
 797 {
 798         int ri;
 799         struct pmc_target *pt;
 800
 801         sx_assert(&pmc_sx, SX_XLOCKED);
 802
 803         KASSERT(pm != NULL && pp != NULL,
 804             ("[pmc,%d] Null pm %p or pp %p", __LINE__, pm, pp));
 805         KASSERT(PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)),
 806             ("[pmc,%d] Attaching a non-process-virtual pmc=%p to pid=%d",
 807                 __LINE__, pm, pp->pp_proc->p_pid));
 808         KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt <= ((int) md->pmd_npmc - 1),
 809             ("[pmc,%d] Illegal reference count %d for process record %p",
 810                 __LINE__, pp->pp_refcnt, (void *) pp));
 811
 812         ri = PMC_TO_ROWINDEX(pm);
 813
 814         PMCDBG(PRC,TLK,1, "link-target pmc=%p ri=%d pmc-process=%p",
 815             pm, ri, pp);
 816
 817 #ifdef  DEBUG
 818         LIST_FOREACH(pt, &pm->pm_targets, pt_next)
 819             if (pt->pt_process == pp)
 820                     KASSERT(0, ("[pmc,%d] pp %p already in pmc %p targets",
 821                                 __LINE__, pp, pm));
 822 #endif
 823
 824         pt = malloc(sizeof(struct pmc_target), M_PMC, M_WAITOK|M_ZERO);
 825         pt->pt_process = pp;
 826
 827         LIST_INSERT_HEAD(&pm->pm_targets, pt, pt_next);
 828
 829         atomic_store_rel_ptr((uintptr_t *)&pp->pp_pmcs[ri].pp_pmc,
 830             (uintptr_t)pm);
 831
 832         if (pm->pm_owner->po_owner == pp->pp_proc)
 833                 pm->pm_flags |= PMC_F_ATTACHED_TO_OWNER;
 834
 835         /*
 836          * Initialize the per-process values at this row index.
 837          */
 838         pp->pp_pmcs[ri].pp_pmcval = PMC_TO_MODE(pm) == PMC_MODE_TS ?
 839             pm->pm_sc.pm_reloadcount : 0;
 840
 841         pp->pp_refcnt++;
 842
 843 }
 844
 845 /*
 846  * Removes the association between a target process and a PMC.
 847  */
 848
 849 static void
 850 pmc_unlink_target_process(struct pmc *pm, struct pmc_process *pp)
 851 {
 852         int ri;
 853         struct proc *p;
 854         struct pmc_target *ptgt;
 855
 856         sx_assert(&pmc_sx, SX_XLOCKED);
 857
 858         KASSERT(pm != NULL && pp != NULL,
 859             ("[pmc,%d] Null pm %p or pp %p", __LINE__, pm, pp));
 860
 861         KASSERT(pp->pp_refcnt >= 1 && pp->pp_refcnt <= (int) md->pmd_npmc,
 862             ("[pmc,%d] Illegal ref count %d on process record %p",
 863                 __LINE__, pp->pp_refcnt, (void *) pp));
 864
 865         ri = PMC_TO_ROWINDEX(pm);
 866
 867         PMCDBG(PRC,TUL,1, "unlink-target pmc=%p ri=%d pmc-process=%p",
 868             pm, ri, pp);
 869
 870         KASSERT(pp->pp_pmcs[ri].pp_pmc == pm,
 871             ("[pmc,%d] PMC ri %d mismatch pmc %p pp->[ri] %p", __LINE__,
 872                 ri, pm, pp->pp_pmcs[ri].pp_pmc));
 873
 874         pp->pp_pmcs[ri].pp_pmc = NULL;
 875         pp->pp_pmcs[ri].pp_pmcval = (pmc_value_t) 0;
 876
 877         /* Remove owner-specific flags */
 878         if (pm->pm_owner->po_owner == pp->pp_proc) {
 879                 pp->pp_flags &= ~PMC_PP_ENABLE_MSR_ACCESS;
 880                 pm->pm_flags &= ~PMC_F_ATTACHED_TO_OWNER;
 881         }
 882
 883         pp->pp_refcnt--;
 884
 885         /* Remove the target process from the PMC structure */
 886         LIST_FOREACH(ptgt, &pm->pm_targets, pt_next)
 887                 if (ptgt->pt_process == pp)
 888                         break;
 889
 890         KASSERT(ptgt != NULL, ("[pmc,%d] process %p (pp: %p) not found "
 891                     "in pmc %p", __LINE__, pp->pp_proc, pp, pm));
 892
 893         LIST_REMOVE(ptgt, pt_next);
 894         free(ptgt, M_PMC);
 895
 896         /* if the PMC now lacks targets, send the owner a SIGIO */
 897         if (LIST_EMPTY(&pm->pm_targets)) {
 898                 p = pm->pm_owner->po_owner;
 899                 PROC_LOCK(p);
 900                 kern_psignal(p, SIGIO);
 901                 PROC_UNLOCK(p);
 902
 903                 PMCDBG(PRC,SIG,2, "signalling proc=%p signal=%d", p,
 904                     SIGIO);
 905         }
 906 }
 907
 908 /*
 909  * Check if PMC 'pm' may be attached to target process 't'.
 910  */
 911
 912 static int
 913 pmc_can_attach(struct pmc *pm, struct proc *t)
 914 {
 915         struct proc *o;         /* pmc owner */
 916         struct ucred *oc, *tc;  /* owner, target credentials */
 917         int decline_attach, i;
 918
 919         /*
 920          * A PMC's owner can always attach that PMC to itself.
 921          */
 922
 923         if ((o = pm->pm_owner->po_owner) == t)
 924                 return 0;
 925
 926         PROC_LOCK(o);
 927         oc = o->p_ucred;
 928         crhold(oc);
 929         PROC_UNLOCK(o);
 930
 931         PROC_LOCK(t);
 932         tc = t->p_ucred;
 933         crhold(tc);
 934         PROC_UNLOCK(t);
 935
 936         /*
 937          * The effective uid of the PMC owner should match at least one
 938          * of the {effective,real,saved} uids of the target process.
 939          */
 940
 941         decline_attach = oc->cr_uid != tc->cr_uid &&
 942             oc->cr_uid != tc->cr_svuid &&
 943             oc->cr_uid != tc->cr_ruid;
 944
 945         /*
 946          * Every one of the target's group ids, must be in the owner's
 947          * group list.
 948          */
 949         for (i = 0; !decline_attach && i < tc->cr_ngroups; i++)
 950                 decline_attach = !groupmember(tc->cr_groups[i], oc);
 951
 952         /* check the read and saved gids too */
 953         if (decline_attach == 0)
 954                 decline_attach = !groupmember(tc->cr_rgid, oc) ||
 955                     !groupmember(tc->cr_svgid, oc);
 956
 957         crfree(tc);
 958         crfree(oc);
 959
 960         return !decline_attach;
 961 }
 962
 963 /*
 964  * Attach a process to a PMC.
 965  */
 966
 967 static int
 968 pmc_attach_one_process(struct proc *p, struct pmc *pm)
 969 {
 970         int ri;
 971         char *fullpath, *freepath;
 972         struct pmc_process      *pp;
 973
 974         sx_assert(&pmc_sx, SX_XLOCKED);
 975
 976         PMCDBG(PRC,ATT,2, "attach-one pm=%p ri=%d proc=%p (%d, %s)", pm,
 977             PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
 978
 979         /*
 980          * Locate the process descriptor corresponding to process 'p',
 981          * allocating space as needed.
 982          *
 983          * Verify that rowindex 'pm_rowindex' is free in the process
 984          * descriptor.
 985          *
 986          * If not, allocate space for a descriptor and link the
 987          * process descriptor and PMC.
 988          */
 989         ri = PMC_TO_ROWINDEX(pm);
 990
 991         if ((pp = pmc_find_process_descriptor(p, PMC_FLAG_ALLOCATE)) == NULL)
 992                 return ENOMEM;
 993
 994         if (pp->pp_pmcs[ri].pp_pmc == pm) /* already present at slot [ri] */
 995                 return EEXIST;
 996
 997         if (pp->pp_pmcs[ri].pp_pmc != NULL)
 998                 return EBUSY;
 999
1000         pmc_link_target_process(pm, pp);
1001
1002         if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)) &&
1003             (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) == 0)
1004                 pm->pm_flags |= PMC_F_NEEDS_LOGFILE;
1005
1006         pm->pm_flags |= PMC_F_ATTACH_DONE; /* mark as attached */
1007
1008         /* issue an attach event to a configured log file */
1009         if (pm->pm_owner->po_flags & PMC_PO_OWNS_LOGFILE) {
1010                 pmc_getfilename(p->p_textvp, &fullpath, &freepath);
1011                 if (p->p_flag & P_KTHREAD) {
1012                         fullpath = kernelname;
1013                         freepath = NULL;
1014                 } else
1015                         pmclog_process_pmcattach(pm, p->p_pid, fullpath);
1016                 if (freepath)
1017                         free(freepath, M_TEMP);
1018                 if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
1019                         pmc_log_process_mappings(pm->pm_owner, p);
1020         }
1021         /* mark process as using HWPMCs */
1022         PROC_LOCK(p);
1023         p->p_flag |= P_HWPMC;
1024         PROC_UNLOCK(p);
1025
1026         return 0;
1027 }
1028
1029 /*
1030  * Attach a process and optionally its children
1031  */
1032
1033 static int
1034 pmc_attach_process(struct proc *p, struct pmc *pm)
1035 {
1036         int error;
1037         struct proc *top;
1038
1039         sx_assert(&pmc_sx, SX_XLOCKED);
1040
1041         PMCDBG(PRC,ATT,1, "attach pm=%p ri=%d proc=%p (%d, %s)", pm,
1042             PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
1043
1044
1045         /*
1046          * If this PMC successfully allowed a GETMSR operation
1047          * in the past, disallow further ATTACHes.
1048          */
1049
1050         if ((pm->pm_flags & PMC_PP_ENABLE_MSR_ACCESS) != 0)
1051                 return EPERM;
1052
1053         if ((pm->pm_flags & PMC_F_DESCENDANTS) == 0)
1054                 return pmc_attach_one_process(p, pm);
1055
1056         /*
1057          * Traverse all child processes, attaching them to
1058          * this PMC.
1059          */
1060
1061         sx_slock(&proctree_lock);
1062
1063         top = p;
1064
1065         for (;;) {
1066                 if ((error = pmc_attach_one_process(p, pm)) != 0)
1067                         break;
1068                 if (!LIST_EMPTY(&p->p_children))
1069                         p = LIST_FIRST(&p->p_children);
1070                 else for (;;) {
1071                         if (p == top)
1072                                 goto done;
1073                         if (LIST_NEXT(p, p_sibling)) {
1074                                 p = LIST_NEXT(p, p_sibling);
1075                                 break;
1076                         }
1077                         p = p->p_pptr;
1078                 }
1079         }
1080
1081         if (error)
1082                 (void) pmc_detach_process(top, pm);
1083
1084  done:
1085         sx_sunlock(&proctree_lock);
1086         return error;
1087 }
1088
1089 /*
1090  * Detach a process from a PMC.  If there are no other PMCs tracking
1091  * this process, remove the process structure from its hash table.  If
1092  * 'flags' contains PMC_FLAG_REMOVE, then free the process structure.
1093  */
1094
1095 static int
1096 pmc_detach_one_process(struct proc *p, struct pmc *pm, int flags)
1097 {
1098         int ri;
1099         struct pmc_process *pp;
1100
1101         sx_assert(&pmc_sx, SX_XLOCKED);
1102
1103         KASSERT(pm != NULL,
1104             ("[pmc,%d] null pm pointer", __LINE__));
1105
1106         ri = PMC_TO_ROWINDEX(pm);
1107
1108         PMCDBG(PRC,ATT,2, "detach-one pm=%p ri=%d proc=%p (%d, %s) flags=0x%x",
1109             pm, ri, p, p->p_pid, p->p_comm, flags);
1110
1111         if ((pp = pmc_find_process_descriptor(p, 0)) == NULL)
1112                 return ESRCH;
1113
1114         if (pp->pp_pmcs[ri].pp_pmc != pm)
1115                 return EINVAL;
1116
1117         pmc_unlink_target_process(pm, pp);
1118
1119         /* Issue a detach entry if a log file is configured */
1120         if (pm->pm_owner->po_flags & PMC_PO_OWNS_LOGFILE)
1121                 pmclog_process_pmcdetach(pm, p->p_pid);
1122
1123         /*
1124          * If there are no PMCs targetting this process, we remove its
1125          * descriptor from the target hash table and unset the P_HWPMC
1126          * flag in the struct proc.
1127          */
1128         KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt <= (int) md->pmd_npmc,
1129             ("[pmc,%d] Illegal refcnt %d for process struct %p",
1130                 __LINE__, pp->pp_refcnt, pp));
1131
1132         if (pp->pp_refcnt != 0) /* still a target of some PMC */
1133                 return 0;
1134
1135         pmc_remove_process_descriptor(pp);
1136
1137         if (flags & PMC_FLAG_REMOVE)
1138                 free(pp, M_PMC);
1139
1140         PROC_LOCK(p);
1141         p->p_flag &= ~P_HWPMC;
1142         PROC_UNLOCK(p);
1143
1144         return 0;
1145 }
1146
1147 /*
1148  * Detach a process and optionally its descendants from a PMC.
1149  */
1150
1151 static int
1152 pmc_detach_process(struct proc *p, struct pmc *pm)
1153 {
1154         struct proc *top;
1155
1156         sx_assert(&pmc_sx, SX_XLOCKED);
1157
1158         PMCDBG(PRC,ATT,1, "detach pm=%p ri=%d proc=%p (%d, %s)", pm,
1159             PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
1160
1161         if ((pm->pm_flags & PMC_F_DESCENDANTS) == 0)
1162                 return pmc_detach_one_process(p, pm, PMC_FLAG_REMOVE);
1163
1164         /*
1165          * Traverse all children, detaching them from this PMC.  We
1166          * ignore errors since we could be detaching a PMC from a
1167          * partially attached proc tree.
1168          */
1169
1170         sx_slock(&proctree_lock);
1171
1172         top = p;
1173
1174         for (;;) {
1175                 (void) pmc_detach_one_process(p, pm, PMC_FLAG_REMOVE);
1176
1177                 if (!LIST_EMPTY(&p->p_children))
1178                         p = LIST_FIRST(&p->p_children);
1179                 else for (;;) {
1180                         if (p == top)
1181                                 goto done;
1182                         if (LIST_NEXT(p, p_sibling)) {
1183                                 p = LIST_NEXT(p, p_sibling);
1184                                 break;
1185                         }
1186                         p = p->p_pptr;
1187                 }
1188         }
1189
1190  done:
1191         sx_sunlock(&proctree_lock);
1192
1193         if (LIST_EMPTY(&pm->pm_targets))
1194                 pm->pm_flags &= ~PMC_F_ATTACH_DONE;
1195
1196         return 0;
1197 }
1198
1199
1200 /*
1201  * Thread context switch IN
1202  */
1203
1204 static void
1205 pmc_process_csw_in(struct thread *td)
1206 {
1207         int cpu;
1208         unsigned int adjri, ri;
1209         struct pmc *pm;
1210         struct proc *p;
1211         struct pmc_cpu *pc;
1212         struct pmc_hw *phw;
1213         pmc_value_t newvalue;
1214         struct pmc_process *pp;
1215         struct pmc_classdep *pcd;
1216
1217         p = td->td_proc;
1218
1219         if ((pp = pmc_find_process_descriptor(p, PMC_FLAG_NONE)) == NULL)
1220                 return;
1221
1222         KASSERT(pp->pp_proc == td->td_proc,
1223             ("[pmc,%d] not my thread state", __LINE__));
1224
1225         critical_enter(); /* no preemption from this point */
1226
1227         cpu = PCPU_GET(cpuid); /* td->td_oncpu is invalid */
1228
1229         PMCDBG(CSW,SWI,1, "cpu=%d proc=%p (%d, %s) pp=%p", cpu, p,
1230             p->p_pid, p->p_comm, pp);
1231
1232         KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
1233             ("[pmc,%d] wierd CPU id %d", __LINE__, cpu));
1234
1235         pc = pmc_pcpu[cpu];
1236
1237         for (ri = 0; ri < md->pmd_npmc; ri++) {
1238
1239                 if ((pm = pp->pp_pmcs[ri].pp_pmc) == NULL)
1240                         continue;
1241
1242                 KASSERT(PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)),
1243                     ("[pmc,%d] Target PMC in non-virtual mode (%d)",
1244                         __LINE__, PMC_TO_MODE(pm)));
1245
1246                 KASSERT(PMC_TO_ROWINDEX(pm) == ri,
1247                     ("[pmc,%d] Row index mismatch pmc %d != ri %d",
1248                         __LINE__, PMC_TO_ROWINDEX(pm), ri));
1249
1250                 /*
1251                  * Only PMCs that are marked as 'RUNNING' need
1252                  * be placed on hardware.
1253                  */
1254
1255                 if (pm->pm_state != PMC_STATE_RUNNING)
1256                         continue;
1257
1258                 /* increment PMC runcount */
1259                 atomic_add_rel_int(&pm->pm_runcount, 1);
1260
1261                 /* configure the HWPMC we are going to use. */
1262                 pcd = pmc_ri_to_classdep(md, ri, &adjri);
1263                 pcd->pcd_config_pmc(cpu, adjri, pm);
1264
1265                 phw = pc->pc_hwpmcs[ri];
1266
1267                 KASSERT(phw != NULL,
1268                     ("[pmc,%d] null hw pointer", __LINE__));
1269
1270                 KASSERT(phw->phw_pmc == pm,
1271                     ("[pmc,%d] hw->pmc %p != pmc %p", __LINE__,
1272                         phw->phw_pmc, pm));
1273
1274                 /*
1275                  * Write out saved value and start the PMC.
1276                  *
1277                  * Sampling PMCs use a per-process value, while
1278                  * counting mode PMCs use a per-pmc value that is
1279                  * inherited across descendants.
1280                  */
1281                 if (PMC_TO_MODE(pm) == PMC_MODE_TS) {
1282                         mtx_pool_lock_spin(pmc_mtxpool, pm);
1283                         newvalue = PMC_PCPU_SAVED(cpu,ri) =
1284                             pp->pp_pmcs[ri].pp_pmcval;
1285                         mtx_pool_unlock_spin(pmc_mtxpool, pm);
1286                 } else {
1287                         KASSERT(PMC_TO_MODE(pm) == PMC_MODE_TC,
1288                             ("[pmc,%d] illegal mode=%d", __LINE__,
1289                             PMC_TO_MODE(pm)));
1290                         mtx_pool_lock_spin(pmc_mtxpool, pm);
1291                         newvalue = PMC_PCPU_SAVED(cpu, ri) =
1292                             pm->pm_gv.pm_savedvalue;
1293                         mtx_pool_unlock_spin(pmc_mtxpool, pm);
1294                 }
1295
1296                 PMCDBG(CSW,SWI,1,"cpu=%d ri=%d new=%jd", cpu, ri, newvalue);
1297
1298                 pcd->pcd_write_pmc(cpu, adjri, newvalue);
1299                 pcd->pcd_start_pmc(cpu, adjri);
1300         }
1301
1302         /*
1303          * perform any other architecture/cpu dependent thread
1304          * switch-in actions.
1305          */
1306
1307         (void) (*md->pmd_switch_in)(pc, pp);
1308
1309         critical_exit();
1310
1311 }
1312
1313 /*
1314  * Thread context switch OUT.
1315  */
1316
1317 static void
1318 pmc_process_csw_out(struct thread *td)
1319 {
1320         int cpu;
1321         int64_t tmp;
1322         struct pmc *pm;
1323         struct proc *p;
1324         enum pmc_mode mode;
1325         struct pmc_cpu *pc;
1326         pmc_value_t newvalue;
1327         unsigned int adjri, ri;
1328         struct pmc_process *pp;
1329         struct pmc_classdep *pcd;
1330
1331
1332         /*
1333          * Locate our process descriptor; this may be NULL if
1334          * this process is exiting and we have already removed
1335          * the process from the target process table.
1336          *
1337          * Note that due to kernel preemption, multiple
1338          * context switches may happen while the process is
1339          * exiting.
1340          *
1341          * Note also that if the target process cannot be
1342          * found we still need to deconfigure any PMCs that
1343          * are currently running on hardware.
1344          */
1345
1346         p = td->td_proc;
1347         pp = pmc_find_process_descriptor(p, PMC_FLAG_NONE);
1348
1349         /*
1350          * save PMCs
1351          */
1352
1353         critical_enter();
1354
1355         cpu = PCPU_GET(cpuid); /* td->td_oncpu is invalid */
1356
1357         PMCDBG(CSW,SWO,1, "cpu=%d proc=%p (%d, %s) pp=%p", cpu, p,
1358             p->p_pid, p->p_comm, pp);
1359
1360         KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
1361             ("[pmc,%d wierd CPU id %d", __LINE__, cpu));
1362
1363         pc = pmc_pcpu[cpu];
1364
1365         /*
1366          * When a PMC gets unlinked from a target PMC, it will
1367          * be removed from the target's pp_pmc[] array.
1368          *
1369          * However, on a MP system, the target could have been
1370          * executing on another CPU at the time of the unlink.
1371          * So, at context switch OUT time, we need to look at
1372          * the hardware to determine if a PMC is scheduled on
1373          * it.
1374          */
1375
1376         for (ri = 0; ri < md->pmd_npmc; ri++) {
1377
1378                 pcd = pmc_ri_to_classdep(md, ri, &adjri);
1379                 pm  = NULL;
1380                 (void) (*pcd->pcd_get_config)(cpu, adjri, &pm);
1381
1382                 if (pm == NULL) /* nothing at this row index */
1383                         continue;
1384
1385                 mode = PMC_TO_MODE(pm);
1386                 if (!PMC_IS_VIRTUAL_MODE(mode))
1387                         continue; /* not a process virtual PMC */
1388
1389                 KASSERT(PMC_TO_ROWINDEX(pm) == ri,
1390                     ("[pmc,%d] ri mismatch pmc(%d) ri(%d)",
1391                         __LINE__, PMC_TO_ROWINDEX(pm), ri));
1392
1393                 /* Stop hardware if not already stopped */
1394                 if (pm->pm_stalled == 0)
1395                         pcd->pcd_stop_pmc(cpu, adjri);
1396
1397                 /* reduce this PMC's runcount */
1398                 atomic_subtract_rel_int(&pm->pm_runcount, 1);
1399
1400                 /*
1401                  * If this PMC is associated with this process,
1402                  * save the reading.
1403                  */
1404
1405                 if (pp != NULL && pp->pp_pmcs[ri].pp_pmc != NULL) {
1406
1407                         KASSERT(pm == pp->pp_pmcs[ri].pp_pmc,
1408                             ("[pmc,%d] pm %p != pp_pmcs[%d] %p", __LINE__,
1409                                 pm, ri, pp->pp_pmcs[ri].pp_pmc));
1410
1411                         KASSERT(pp->pp_refcnt > 0,
1412                             ("[pmc,%d] pp refcnt = %d", __LINE__,
1413                                 pp->pp_refcnt));
1414
1415                         pcd->pcd_read_pmc(cpu, adjri, &newvalue);
1416
1417                         tmp = newvalue - PMC_PCPU_SAVED(cpu,ri);
1418
1419                         PMCDBG(CSW,SWO,1,"cpu=%d ri=%d tmp=%jd", cpu, ri,
1420                             tmp);
1421
1422                         if (mode == PMC_MODE_TS) {
1423
1424                                 /*
1425                                  * For sampling process-virtual PMCs,
1426                                  * we expect the count to be
1427                                  * decreasing as the 'value'
1428                                  * programmed into the PMC is the
1429                                  * number of events to be seen till
1430                                  * the next sampling interrupt.
1431                                  */
1432                                 if (tmp < 0)
1433                                         tmp += pm->pm_sc.pm_reloadcount;
1434                                 mtx_pool_lock_spin(pmc_mtxpool, pm);
1435                                 pp->pp_pmcs[ri].pp_pmcval -= tmp;
1436                                 if ((int64_t) pp->pp_pmcs[ri].pp_pmcval < 0)
1437                                         pp->pp_pmcs[ri].pp_pmcval +=
1438                                             pm->pm_sc.pm_reloadcount;
1439                                 mtx_pool_unlock_spin(pmc_mtxpool, pm);
1440
1441                         } else {
1442
1443                                 /*
1444                                  * For counting process-virtual PMCs,
1445                                  * we expect the count to be
1446                                  * increasing monotonically, modulo a 64
1447                                  * bit wraparound.
1448                                  */
1449                                 KASSERT((int64_t) tmp >= 0,
1450                                     ("[pmc,%d] negative increment cpu=%d "
1451                                      "ri=%d newvalue=%jx saved=%jx "
1452                                      "incr=%jx", __LINE__, cpu, ri,
1453                                      newvalue, PMC_PCPU_SAVED(cpu,ri), tmp));
1454
1455                                 mtx_pool_lock_spin(pmc_mtxpool, pm);
1456                                 pm->pm_gv.pm_savedvalue += tmp;
1457                                 pp->pp_pmcs[ri].pp_pmcval += tmp;
1458                                 mtx_pool_unlock_spin(pmc_mtxpool, pm);
1459
1460                                 if (pm->pm_flags & PMC_F_LOG_PROCCSW)
1461                                         pmclog_process_proccsw(pm, pp, tmp);
1462                         }
1463                 }
1464
1465                 /* mark hardware as free */
1466                 pcd->pcd_config_pmc(cpu, adjri, NULL);
1467         }
1468
1469         /*
1470          * perform any other architecture/cpu dependent thread
1471          * switch out functions.
1472          */
1473
1474         (void) (*md->pmd_switch_out)(pc, pp);
1475
1476         critical_exit();
1477 }
1478
1479 /*
1480  * A mapping change for a process.
1481  */
1482
1483 static void
1484 pmc_process_mmap(struct thread *td, struct pmckern_map_in *pkm)
1485 {
1486         int ri;
1487         pid_t pid;
1488         char *fullpath, *freepath;
1489         const struct pmc *pm;
1490         struct pmc_owner *po;
1491         const struct pmc_process *pp;
1492
1493         freepath = fullpath = NULL;
1494         pmc_getfilename((struct vnode *) pkm->pm_file, &fullpath, &freepath);
1495
1496         pid = td->td_proc->p_pid;
1497
1498         /* Inform owners of all system-wide sampling PMCs. */
1499         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1500             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1501                 pmclog_process_map_in(po, pid, pkm->pm_address, fullpath);
1502
1503         if ((pp = pmc_find_process_descriptor(td->td_proc, 0)) == NULL)
1504                 goto done;
1505
1506         /*
1507          * Inform sampling PMC owners tracking this process.
1508          */
1509         for (ri = 0; ri < md->pmd_npmc; ri++)
1510                 if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL &&
1511                     PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
1512                         pmclog_process_map_in(pm->pm_owner,
1513                             pid, pkm->pm_address, fullpath);
1514
1515   done:
1516         if (freepath)
1517                 free(freepath, M_TEMP);
1518 }
1519
1520
1521 /*
1522  * Log an munmap request.
1523  */
1524
1525 static void
1526 pmc_process_munmap(struct thread *td, struct pmckern_map_out *pkm)
1527 {
1528         int ri;
1529         pid_t pid;
1530         struct pmc_owner *po;
1531         const struct pmc *pm;
1532         const struct pmc_process *pp;
1533
1534         pid = td->td_proc->p_pid;
1535
1536         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1537             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1538                 pmclog_process_map_out(po, pid, pkm->pm_address,
1539                     pkm->pm_address + pkm->pm_size);
1540
1541         if ((pp = pmc_find_process_descriptor(td->td_proc, 0)) == NULL)
1542                 return;
1543
1544         for (ri = 0; ri < md->pmd_npmc; ri++)
1545                 if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL &&
1546                     PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
1547                         pmclog_process_map_out(pm->pm_owner, pid,
1548                             pkm->pm_address, pkm->pm_address + pkm->pm_size);
1549 }
1550
1551 /*
1552  * Log mapping information about the kernel.
1553  */
1554
1555 static void
1556 pmc_log_kernel_mappings(struct pmc *pm)
1557 {
1558         struct pmc_owner *po;
1559         struct pmckern_map_in *km, *kmbase;
1560
1561         sx_assert(&pmc_sx, SX_LOCKED);
1562         KASSERT(PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)),
1563             ("[pmc,%d] non-sampling PMC (%p) desires mapping information",
1564                 __LINE__, (void *) pm));
1565
1566         po = pm->pm_owner;
1567
1568         if (po->po_flags & PMC_PO_INITIAL_MAPPINGS_DONE)
1569                 return;
1570
1571         /*
1572          * Log the current set of kernel modules.
1573          */
1574         kmbase = linker_hwpmc_list_objects();
1575         for (km = kmbase; km->pm_file != NULL; km++) {
1576                 PMCDBG(LOG,REG,1,"%s %p", (char *) km->pm_file,
1577                     (void *) km->pm_address);
1578                 pmclog_process_map_in(po, (pid_t) -1, km->pm_address,
1579                     km->pm_file);
1580         }
1581         free(kmbase, M_LINKER);
1582
1583         po->po_flags |= PMC_PO_INITIAL_MAPPINGS_DONE;
1584 }
1585
1586 /*
1587  * Log the mappings for a single process.
1588  */
1589
1590 static void
1591 pmc_log_process_mappings(struct pmc_owner *po, struct proc *p)
1592 {
1593         vm_map_t map;
1594         struct vnode *vp;
1595         struct vmspace *vm;
1596         vm_map_entry_t entry;
1597         vm_offset_t last_end;
1598         u_int last_timestamp;
1599         struct vnode *last_vp;
1600         vm_offset_t start_addr;
1601         vm_object_t obj, lobj, tobj;
1602         char *fullpath, *freepath;
1603
1604         last_vp = NULL;
1605         last_end = (vm_offset_t) 0;
1606         fullpath = freepath = NULL;
1607
1608         if ((vm = vmspace_acquire_ref(p)) == NULL)
1609                 return;
1610
1611         map = &vm->vm_map;
1612         vm_map_lock_read(map);
1613
1614         for (entry = map->header.next; entry != &map->header; entry = entry->next) {
1615
1616                 if (entry == NULL) {
1617                         PMCDBG(LOG,OPS,2, "hwpmc: vm_map entry unexpectedly "
1618                             "NULL! pid=%d vm_map=%p\n", p->p_pid, map);
1619                         break;
1620                 }
1621
1622                 /*
1623                  * We only care about executable map entries.
1624                  */
1625                 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) ||
1626                     !(entry->protection & VM_PROT_EXECUTE) ||
1627                     (entry->object.vm_object == NULL)) {
1628                         continue;
1629                 }
1630
1631                 obj = entry->object.vm_object;
1632                 VM_OBJECT_RLOCK(obj);
1633
1634                 /*
1635                  * Walk the backing_object list to find the base
1636                  * (non-shadowed) vm_object.
1637                  */
1638                 for (lobj = tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
1639                         if (tobj != obj)
1640                                 VM_OBJECT_RLOCK(tobj);
1641                         if (lobj != obj)
1642                                 VM_OBJECT_RUNLOCK(lobj);
1643                         lobj = tobj;
1644                 }
1645
1646                 /*
1647                  * At this point lobj is the base vm_object and it is locked.
1648                  */
1649                 if (lobj == NULL) {
1650                         PMCDBG(LOG,OPS,2, "hwpmc: lobj unexpectedly NULL! pid=%d "
1651                             "vm_map=%p vm_obj=%p\n", p->p_pid, map, obj);
1652                         VM_OBJECT_RUNLOCK(obj);
1653                         continue;
1654                 }
1655
1656                 if (lobj->type != OBJT_VNODE || lobj->handle == NULL) {
1657                         if (lobj != obj)
1658                                 VM_OBJECT_RUNLOCK(lobj);
1659                         VM_OBJECT_RUNLOCK(obj);
1660                         continue;
1661                 }
1662
1663                 /*
1664                  * Skip contiguous regions that point to the same
1665                  * vnode, so we don't emit redundant MAP-IN
1666                  * directives.
1667                  */
1668                 if (entry->start == last_end && lobj->handle == last_vp) {
1669                         last_end = entry->end;
1670                         if (lobj != obj)
1671                                 VM_OBJECT_RUNLOCK(lobj);
1672                         VM_OBJECT_RUNLOCK(obj);
1673                         continue;
1674                 }
1675
1676                 /*
1677                  * We don't want to keep the proc's vm_map or this
1678                  * vm_object locked while we walk the pathname, since
1679                  * vn_fullpath() can sleep.  However, if we drop the
1680                  * lock, it's possible for concurrent activity to
1681                  * modify the vm_map list.  To protect against this,
1682                  * we save the vm_map timestamp before we release the
1683                  * lock, and check it after we reacquire the lock
1684                  * below.
1685                  */
1686                 start_addr = entry->start;
1687                 last_end = entry->end;
1688                 last_timestamp = map->timestamp;
1689                 vm_map_unlock_read(map);
1690
1691                 vp = lobj->handle;
1692                 vref(vp);
1693                 if (lobj != obj)
1694                         VM_OBJECT_RUNLOCK(lobj);
1695
1696                 VM_OBJECT_RUNLOCK(obj);
1697
1698                 freepath = NULL;
1699                 pmc_getfilename(vp, &fullpath, &freepath);
1700                 last_vp = vp;
1701
1702                 vrele(vp);
1703
1704                 vp = NULL;
1705                 pmclog_process_map_in(po, p->p_pid, start_addr, fullpath);
1706                 if (freepath)
1707                         free(freepath, M_TEMP);
1708
1709                 vm_map_lock_read(map);
1710
1711                 /*
1712                  * If our saved timestamp doesn't match, this means
1713                  * that the vm_map was modified out from under us and
1714                  * we can't trust our current "entry" pointer.  Do a
1715                  * new lookup for this entry.  If there is no entry
1716                  * for this address range, vm_map_lookup_entry() will
1717                  * return the previous one, so we always want to go to
1718                  * entry->next on the next loop iteration.
1719                  *
1720                  * There is an edge condition here that can occur if
1721                  * there is no entry at or before this address.  In
1722                  * this situation, vm_map_lookup_entry returns
1723                  * &map->header, which would cause our loop to abort
1724                  * without processing the rest of the map.  However,
1725                  * in practice this will never happen for process
1726                  * vm_map.  This is because the executable's text
1727                  * segment is the first mapping in the proc's address
1728                  * space, and this mapping is never removed until the
1729                  * process exits, so there will always be a non-header
1730                  * entry at or before the requested address for
1731                  * vm_map_lookup_entry to return.
1732                  */
1733                 if (map->timestamp != last_timestamp)
1734                         vm_map_lookup_entry(map, last_end - 1, &entry);
1735         }
1736
1737         vm_map_unlock_read(map);
1738         vmspace_free(vm);
1739         return;
1740 }
1741
1742 /*
1743  * Log mappings for all processes in the system.
1744  */
1745
1746 static void
1747 pmc_log_all_process_mappings(struct pmc_owner *po)
1748 {
1749         struct proc *p, *top;
1750
1751         sx_assert(&pmc_sx, SX_XLOCKED);
1752
1753         if ((p = pfind(1)) == NULL)
1754                 panic("[pmc,%d] Cannot find init", __LINE__);
1755
1756         PROC_UNLOCK(p);
1757
1758         sx_slock(&proctree_lock);
1759
1760         top = p;
1761
1762         for (;;) {
1763                 pmc_log_process_mappings(po, p);
1764                 if (!LIST_EMPTY(&p->p_children))
1765                         p = LIST_FIRST(&p->p_children);
1766                 else for (;;) {
1767                         if (p == top)
1768                                 goto done;
1769                         if (LIST_NEXT(p, p_sibling)) {
1770                                 p = LIST_NEXT(p, p_sibling);
1771                                 break;
1772                         }
1773                         p = p->p_pptr;
1774                 }
1775         }
1776  done:
1777         sx_sunlock(&proctree_lock);
1778 }
1779
1780 /*
1781  * The 'hook' invoked from the kernel proper
1782  */
1783
1784
1785 #ifdef  DEBUG
1786 const char *pmc_hooknames[] = {
1787         /* these strings correspond to PMC_FN_* in <sys/pmckern.h> */
1788         "",
1789         "EXEC",
1790         "CSW-IN",
1791         "CSW-OUT",
1792         "SAMPLE",
1793         "UNUSED1",
1794         "UNUSED2",
1795         "MMAP",
1796         "MUNMAP",
1797         "CALLCHAIN-NMI",
1798         "CALLCHAIN-SOFT",
1799         "SOFTSAMPLING"
1800 };
1801 #endif
1802
1803 static int
1804 pmc_hook_handler(struct thread *td, int function, void *arg)
1805 {
1806
1807         PMCDBG(MOD,PMH,1, "hook td=%p func=%d \"%s\" arg=%p", td, function,
1808             pmc_hooknames[function], arg);
1809
1810         switch (function)
1811         {
1812
1813         /*
1814          * Process exec()
1815          */
1816
1817         case PMC_FN_PROCESS_EXEC:
1818         {
1819                 char *fullpath, *freepath;
1820                 unsigned int ri;
1821                 int is_using_hwpmcs;
1822                 struct pmc *pm;
1823                 struct proc *p;
1824                 struct pmc_owner *po;
1825                 struct pmc_process *pp;
1826                 struct pmckern_procexec *pk;
1827
1828                 sx_assert(&pmc_sx, SX_XLOCKED);
1829
1830                 p = td->td_proc;
1831                 pmc_getfilename(p->p_textvp, &fullpath, &freepath);
1832
1833                 pk = (struct pmckern_procexec *) arg;
1834
1835                 /* Inform owners of SS mode PMCs of the exec event. */
1836                 LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1837                     if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1838                             pmclog_process_procexec(po, PMC_ID_INVALID,
1839                                 p->p_pid, pk->pm_entryaddr, fullpath);
1840
1841                 PROC_LOCK(p);
1842                 is_using_hwpmcs = p->p_flag & P_HWPMC;
1843                 PROC_UNLOCK(p);
1844
1845                 if (!is_using_hwpmcs) {
1846                         if (freepath)
1847                                 free(freepath, M_TEMP);
1848                         break;
1849                 }
1850
1851                 /*
1852                  * PMCs are not inherited across an exec():  remove any
1853                  * PMCs that this process is the owner of.
1854                  */
1855
1856                 if ((po = pmc_find_owner_descriptor(p)) != NULL) {
1857                         pmc_remove_owner(po);
1858                         pmc_destroy_owner_descriptor(po);
1859                 }
1860
1861                 /*
1862                  * If the process being exec'ed is not the target of any
1863                  * PMC, we are done.
1864                  */
1865                 if ((pp = pmc_find_process_descriptor(p, 0)) == NULL) {
1866                         if (freepath)
1867                                 free(freepath, M_TEMP);
1868                         break;
1869                 }
1870
1871                 /*
1872                  * Log the exec event to all monitoring owners.  Skip
1873                  * owners who have already recieved the event because
1874                  * they had system sampling PMCs active.
1875                  */
1876                 for (ri = 0; ri < md->pmd_npmc; ri++)
1877                         if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL) {
1878                                 po = pm->pm_owner;
1879                                 if (po->po_sscount == 0 &&
1880                                     po->po_flags & PMC_PO_OWNS_LOGFILE)
1881                                         pmclog_process_procexec(po, pm->pm_id,
1882                                             p->p_pid, pk->pm_entryaddr,
1883                                             fullpath);
1884                         }
1885
1886                 if (freepath)
1887                         free(freepath, M_TEMP);
1888
1889
1890                 PMCDBG(PRC,EXC,1, "exec proc=%p (%d, %s) cred-changed=%d",
1891                     p, p->p_pid, p->p_comm, pk->pm_credentialschanged);
1892
1893                 if (pk->pm_credentialschanged == 0) /* no change */
1894                         break;
1895
1896                 /*
1897                  * If the newly exec()'ed process has a different credential
1898                  * than before, allow it to be the target of a PMC only if
1899                  * the PMC's owner has sufficient priviledge.
1900                  */
1901
1902                 for (ri = 0; ri < md->pmd_npmc; ri++)
1903                         if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL)
1904                                 if (pmc_can_attach(pm, td->td_proc) != 0)
1905                                         pmc_detach_one_process(td->td_proc,
1906                                             pm, PMC_FLAG_NONE);
1907
1908                 KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt <= (int) md->pmd_npmc,
1909                     ("[pmc,%d] Illegal ref count %d on pp %p", __LINE__,
1910                         pp->pp_refcnt, pp));
1911
1912                 /*
1913                  * If this process is no longer the target of any
1914                  * PMCs, we can remove the process entry and free
1915                  * up space.
1916                  */
1917
1918                 if (pp->pp_refcnt == 0) {
1919                         pmc_remove_process_descriptor(pp);
1920                         free(pp, M_PMC);
1921                         break;
1922                 }
1923
1924         }
1925         break;
1926
1927         case PMC_FN_CSW_IN:
1928                 pmc_process_csw_in(td);
1929                 break;
1930
1931         case PMC_FN_CSW_OUT:
1932                 pmc_process_csw_out(td);
1933                 break;
1934
1935         /*
1936          * Process accumulated PC samples.
1937          *
1938          * This function is expected to be called by hardclock() for
1939          * each CPU that has accumulated PC samples.
1940          *
1941          * This function is to be executed on the CPU whose samples
1942          * are being processed.
1943          */
1944         case PMC_FN_DO_SAMPLES:
1945
1946                 /*
1947                  * Clear the cpu specific bit in the CPU mask before
1948                  * do the rest of the processing.  If the NMI handler
1949                  * gets invoked after the "atomic_clear_int()" call
1950                  * below but before "pmc_process_samples()" gets
1951                  * around to processing the interrupt, then we will
1952                  * come back here at the next hardclock() tick (and
1953                  * may find nothing to do if "pmc_process_samples()"
1954                  * had already processed the interrupt).  We don't
1955                  * lose the interrupt sample.
1956                  */
1957                 CPU_CLR_ATOMIC(PCPU_GET(cpuid), &pmc_cpumask);
1958                 pmc_process_samples(PCPU_GET(cpuid), PMC_HR);
1959                 pmc_process_samples(PCPU_GET(cpuid), PMC_SR);
1960                 break;
1961
1962         case PMC_FN_MMAP:
1963                 sx_assert(&pmc_sx, SX_LOCKED);
1964                 pmc_process_mmap(td, (struct pmckern_map_in *) arg);
1965                 break;
1966
1967         case PMC_FN_MUNMAP:
1968                 sx_assert(&pmc_sx, SX_LOCKED);
1969                 pmc_process_munmap(td, (struct pmckern_map_out *) arg);
1970                 break;
1971
1972         case PMC_FN_USER_CALLCHAIN:
1973                 /*
1974                  * Record a call chain.
1975                  */
1976                 KASSERT(td == curthread, ("[pmc,%d] td != curthread",
1977                     __LINE__));
1978
1979                 pmc_capture_user_callchain(PCPU_GET(cpuid), PMC_HR,
1980                     (struct trapframe *) arg);
1981                 td->td_pflags &= ~TDP_CALLCHAIN;
1982                 break;
1983
1984         case PMC_FN_USER_CALLCHAIN_SOFT:
1985                 /*
1986                  * Record a call chain.
1987                  */
1988                 KASSERT(td == curthread, ("[pmc,%d] td != curthread",
1989                     __LINE__));
1990                 pmc_capture_user_callchain(PCPU_GET(cpuid), PMC_SR,
1991                     (struct trapframe *) arg);
1992                 td->td_pflags &= ~TDP_CALLCHAIN;
1993                 break;
1994
1995         case PMC_FN_SOFT_SAMPLING:
1996                 /*
1997                  * Call soft PMC sampling intr.
1998                  */
1999                 pmc_soft_intr((struct pmckern_soft *) arg);
2000                 break;
2001
2002         default:
2003 #ifdef  DEBUG
2004                 KASSERT(0, ("[pmc,%d] unknown hook %d\n", __LINE__, function));
2005 #endif
2006                 break;
2007
2008         }
2009
2010         return 0;
2011 }
2012
2013 /*
2014  * allocate a 'struct pmc_owner' descriptor in the owner hash table.
2015  */
2016
2017 static struct pmc_owner *
2018 pmc_allocate_owner_descriptor(struct proc *p)
2019 {
2020         uint32_t hindex;
2021         struct pmc_owner *po;
2022         struct pmc_ownerhash *poh;
2023
2024         hindex = PMC_HASH_PTR(p, pmc_ownerhashmask);
2025         poh = &pmc_ownerhash[hindex];
2026
2027         /* allocate space for N pointers and one descriptor struct */
2028         po = malloc(sizeof(struct pmc_owner), M_PMC, M_WAITOK|M_ZERO);
2029         po->po_owner = p;
2030         LIST_INSERT_HEAD(poh, po, po_next); /* insert into hash table */
2031
2032         TAILQ_INIT(&po->po_logbuffers);
2033         mtx_init(&po->po_mtx, "pmc-owner-mtx", "pmc-per-proc", MTX_SPIN);
2034
2035         PMCDBG(OWN,ALL,1, "allocate-owner proc=%p (%d, %s) pmc-owner=%p",
2036             p, p->p_pid, p->p_comm, po);
2037
2038         return po;
2039 }
2040
2041 static void
2042 pmc_destroy_owner_descriptor(struct pmc_owner *po)
2043 {
2044
2045         PMCDBG(OWN,REL,1, "destroy-owner po=%p proc=%p (%d, %s)",
2046             po, po->po_owner, po->po_owner->p_pid, po->po_owner->p_comm);
2047
2048         mtx_destroy(&po->po_mtx);
2049         free(po, M_PMC);
2050 }
2051
2052 /*
2053  * find the descriptor corresponding to process 'p', adding or removing it
2054  * as specified by 'mode'.
2055  */
2056
2057 static struct pmc_process *
2058 pmc_find_process_descriptor(struct proc *p, uint32_t mode)
2059 {
2060         uint32_t hindex;
2061         struct pmc_process *pp, *ppnew;
2062         struct pmc_processhash *pph;
2063
2064         hindex = PMC_HASH_PTR(p, pmc_processhashmask);
2065         pph = &pmc_processhash[hindex];
2066
2067         ppnew = NULL;
2068
2069         /*
2070          * Pre-allocate memory in the FIND_ALLOCATE case since we
2071          * cannot call malloc(9) once we hold a spin lock.
2072          */
2073         if (mode & PMC_FLAG_ALLOCATE)
2074                 ppnew = malloc(sizeof(struct pmc_process) + md->pmd_npmc *
2075                     sizeof(struct pmc_targetstate), M_PMC, M_WAITOK|M_ZERO);
2076
2077         mtx_lock_spin(&pmc_processhash_mtx);
2078         LIST_FOREACH(pp, pph, pp_next)
2079             if (pp->pp_proc == p)
2080                     break;
2081
2082         if ((mode & PMC_FLAG_REMOVE) && pp != NULL)
2083                 LIST_REMOVE(pp, pp_next);
2084
2085         if ((mode & PMC_FLAG_ALLOCATE) && pp == NULL &&
2086             ppnew != NULL) {
2087                 ppnew->pp_proc = p;
2088                 LIST_INSERT_HEAD(pph, ppnew, pp_next);
2089                 pp = ppnew;
2090                 ppnew = NULL;
2091         }
2092         mtx_unlock_spin(&pmc_processhash_mtx);
2093
2094         if (pp != NULL && ppnew != NULL)
2095                 free(ppnew, M_PMC);
2096
2097         return pp;
2098 }
2099
2100 /*
2101  * remove a process descriptor from the process hash table.
2102  */
2103
2104 static void
2105 pmc_remove_process_descriptor(struct pmc_process *pp)
2106 {
2107         KASSERT(pp->pp_refcnt == 0,
2108             ("[pmc,%d] Removing process descriptor %p with count %d",
2109                 __LINE__, pp, pp->pp_refcnt));
2110
2111         mtx_lock_spin(&pmc_processhash_mtx);
2112         LIST_REMOVE(pp, pp_next);
2113         mtx_unlock_spin(&pmc_processhash_mtx);
2114 }
2115
2116
2117 /*
2118  * find an owner descriptor corresponding to proc 'p'
2119  */
2120
2121 static struct pmc_owner *
2122 pmc_find_owner_descriptor(struct proc *p)
2123 {
2124         uint32_t hindex;
2125         struct pmc_owner *po;
2126         struct pmc_ownerhash *poh;
2127
2128         hindex = PMC_HASH_PTR(p, pmc_ownerhashmask);
2129         poh = &pmc_ownerhash[hindex];
2130
2131         po = NULL;
2132         LIST_FOREACH(po, poh, po_next)
2133             if (po->po_owner == p)
2134                     break;
2135
2136         PMCDBG(OWN,FND,1, "find-owner proc=%p (%d, %s) hindex=0x%x -> "
2137             "pmc-owner=%p", p, p->p_pid, p->p_comm, hindex, po);
2138
2139         return po;
2140 }
2141
2142 /*
2143  * pmc_allocate_pmc_descriptor
2144  *
2145  * Allocate a pmc descriptor and initialize its
2146  * fields.
2147  */
2148
2149 static struct pmc *
2150 pmc_allocate_pmc_descriptor(void)
2151 {
2152         struct pmc *pmc;
2153
2154         pmc = malloc(sizeof(struct pmc), M_PMC, M_WAITOK|M_ZERO);
2155
2156         PMCDBG(PMC,ALL,1, "allocate-pmc -> pmc=%p", pmc);
2157
2158         return pmc;
2159 }
2160
2161 /*
2162  * Destroy a pmc descriptor.
2163  */
2164
2165 static void
2166 pmc_destroy_pmc_descriptor(struct pmc *pm)
2167 {
2168         (void) pm;
2169
2170 #ifdef  DEBUG
2171         KASSERT(pm->pm_state == PMC_STATE_DELETED ||
2172             pm->pm_state == PMC_STATE_FREE,
2173             ("[pmc,%d] destroying non-deleted PMC", __LINE__));
2174         KASSERT(LIST_EMPTY(&pm->pm_targets),
2175             ("[pmc,%d] destroying pmc with targets", __LINE__));
2176         KASSERT(pm->pm_owner == NULL,
2177             ("[pmc,%d] destroying pmc attached to an owner", __LINE__));
2178         KASSERT(pm->pm_runcount == 0,
2179             ("[pmc,%d] pmc has non-zero run count %d", __LINE__,
2180                 pm->pm_runcount));
2181 #endif
2182 }
2183
2184 static void
2185 pmc_wait_for_pmc_idle(struct pmc *pm)
2186 {
2187 #ifdef DEBUG
2188         volatile int maxloop;
2189
2190         maxloop = 100 * pmc_cpu_max();
2191 #endif
2192         /*
2193          * Loop (with a forced context switch) till the PMC's runcount
2194          * comes down to zero.
2195          */
2196         while (atomic_load_acq_32(&pm->pm_runcount) > 0) {
2197 #ifdef DEBUG
2198                 maxloop--;
2199                 KASSERT(maxloop > 0,
2200                     ("[pmc,%d] (ri%d, rc%d) waiting too long for "
2201                         "pmc to be free", __LINE__,
2202                         PMC_TO_ROWINDEX(pm), pm->pm_runcount));
2203 #endif
2204                 pmc_force_context_switch();
2205         }
2206 }
2207
2208 /*
2209  * This function does the following things:
2210  *
2211  *  - detaches the PMC from hardware
2212  *  - unlinks all target threads that were attached to it
2213  *  - removes the PMC from its owner's list
2214  *  - destroy's the PMC private mutex
2215  *
2216  * Once this function completes, the given pmc pointer can be safely
2217  * FREE'd by the caller.
2218  */
2219
2220 static void
2221 pmc_release_pmc_descriptor(struct pmc *pm)
2222 {
2223         enum pmc_mode mode;
2224         struct pmc_hw *phw;
2225         u_int adjri, ri, cpu;
2226         struct pmc_owner *po;
2227         struct pmc_binding pb;
2228         struct pmc_process *pp;
2229         struct pmc_classdep *pcd;
2230         struct pmc_target *ptgt, *tmp;
2231
2232         sx_assert(&pmc_sx, SX_XLOCKED);
2233
2234         KASSERT(pm, ("[pmc,%d] null pmc", __LINE__));
2235
2236         ri   = PMC_TO_ROWINDEX(pm);
2237         pcd  = pmc_ri_to_classdep(md, ri, &adjri);
2238         mode = PMC_TO_MODE(pm);
2239
2240         PMCDBG(PMC,REL,1, "release-pmc pmc=%p ri=%d mode=%d", pm, ri,
2241             mode);
2242
2243         /*
2244          * First, we take the PMC off hardware.
2245          */
2246         cpu = 0;
2247         if (PMC_IS_SYSTEM_MODE(mode)) {
2248
2249                 /*
2250                  * A system mode PMC runs on a specific CPU.  Switch
2251                  * to this CPU and turn hardware off.
2252                  */
2253                 pmc_save_cpu_binding(&pb);
2254
2255                 cpu = PMC_TO_CPU(pm);
2256
2257                 pmc_select_cpu(cpu);
2258
2259                 /* switch off non-stalled CPUs */
2260                 if (pm->pm_state == PMC_STATE_RUNNING &&
2261                     pm->pm_stalled == 0) {
2262
2263                         phw = pmc_pcpu[cpu]->pc_hwpmcs[ri];
2264
2265                         KASSERT(phw->phw_pmc == pm,
2266                             ("[pmc, %d] pmc ptr ri(%d) hw(%p) pm(%p)",
2267                                 __LINE__, ri, phw->phw_pmc, pm));
2268                         PMCDBG(PMC,REL,2, "stopping cpu=%d ri=%d", cpu, ri);
2269
2270                         critical_enter();
2271                         pcd->pcd_stop_pmc(cpu, adjri);
2272                         critical_exit();
2273                 }
2274
2275                 PMCDBG(PMC,REL,2, "decfg cpu=%d ri=%d", cpu, ri);
2276
2277                 critical_enter();
2278                 pcd->pcd_config_pmc(cpu, adjri, NULL);
2279                 critical_exit();
2280
2281                 /* adjust the global and process count of SS mode PMCs */
2282                 if (mode == PMC_MODE_SS && pm->pm_state == PMC_STATE_RUNNING) {
2283                         po = pm->pm_owner;
2284                         po->po_sscount--;
2285                         if (po->po_sscount == 0) {
2286                                 atomic_subtract_rel_int(&pmc_ss_count, 1);
2287                                 LIST_REMOVE(po, po_ssnext);
2288                         }
2289                 }
2290
2291                 pm->pm_state = PMC_STATE_DELETED;
2292
2293                 pmc_restore_cpu_binding(&pb);
2294
2295                 /*
2296                  * We could have references to this PMC structure in
2297                  * the per-cpu sample queues.  Wait for the queue to
2298                  * drain.
2299                  */
2300                 pmc_wait_for_pmc_idle(pm);
2301
2302         } else if (PMC_IS_VIRTUAL_MODE(mode)) {
2303
2304                 /*
2305                  * A virtual PMC could be running on multiple CPUs at
2306                  * a given instant.
2307                  *
2308                  * By marking its state as DELETED, we ensure that
2309                  * this PMC is never further scheduled on hardware.
2310                  *
2311                  * Then we wait till all CPUs are done with this PMC.
2312                  */
2313                 pm->pm_state = PMC_STATE_DELETED;
2314
2315
2316                 /* Wait for the PMCs runcount to come to zero. */
2317                 pmc_wait_for_pmc_idle(pm);
2318
2319                 /*
2320                  * At this point the PMC is off all CPUs and cannot be
2321                  * freshly scheduled onto a CPU.  It is now safe to
2322                  * unlink all targets from this PMC.  If a
2323                  * process-record's refcount falls to zero, we remove
2324                  * it from the hash table.  The module-wide SX lock
2325                  * protects us from races.
2326                  */
2327                 LIST_FOREACH_SAFE(ptgt, &pm->pm_targets, pt_next, tmp) {
2328                         pp = ptgt->pt_process;
2329                         pmc_unlink_target_process(pm, pp); /* frees 'ptgt' */
2330
2331                         PMCDBG(PMC,REL,3, "pp->refcnt=%d", pp->pp_refcnt);
2332
2333                         /*
2334                          * If the target process record shows that no
2335                          * PMCs are attached to it, reclaim its space.
2336                          */
2337
2338                         if (pp->pp_refcnt == 0) {
2339                                 pmc_remove_process_descriptor(pp);
2340                                 free(pp, M_PMC);
2341                         }
2342                 }
2343
2344                 cpu = curthread->td_oncpu; /* setup cpu for pmd_release() */
2345
2346         }
2347
2348         /*
2349          * Release any MD resources
2350          */
2351         (void) pcd->pcd_release_pmc(cpu, adjri, pm);
2352
2353         /*
2354          * Update row disposition
2355          */
2356
2357         if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm)))
2358                 PMC_UNMARK_ROW_STANDALONE(ri);
2359         else
2360                 PMC_UNMARK_ROW_THREAD(ri);
2361
2362         /* unlink from the owner's list */
2363         if (pm->pm_owner) {
2364                 LIST_REMOVE(pm, pm_next);
2365                 pm->pm_owner = NULL;
2366         }
2367
2368         pmc_destroy_pmc_descriptor(pm);
2369 }
2370
2371 /*
2372  * Register an owner and a pmc.
2373  */
2374
2375 static int
2376 pmc_register_owner(struct proc *p, struct pmc *pmc)
2377 {
2378         struct pmc_owner *po;
2379
2380         sx_assert(&pmc_sx, SX_XLOCKED);
2381
2382         if ((po = pmc_find_owner_descriptor(p)) == NULL)
2383                 if ((po = pmc_allocate_owner_descriptor(p)) == NULL)
2384                         return ENOMEM;
2385
2386         KASSERT(pmc->pm_owner == NULL,
2387             ("[pmc,%d] attempting to own an initialized PMC", __LINE__));
2388         pmc->pm_owner  = po;
2389
2390         LIST_INSERT_HEAD(&po->po_pmcs, pmc, pm_next);
2391
2392         PROC_LOCK(p);
2393         p->p_flag |= P_HWPMC;
2394         PROC_UNLOCK(p);
2395
2396         if (po->po_flags & PMC_PO_OWNS_LOGFILE)
2397                 pmclog_process_pmcallocate(pmc);
2398
2399         PMCDBG(PMC,REG,1, "register-owner pmc-owner=%p pmc=%p",
2400             po, pmc);
2401
2402         return 0;
2403 }
2404
2405 /*
2406  * Return the current row disposition:
2407  * == 0 => FREE
2408  *  > 0 => PROCESS MODE
2409  *  < 0 => SYSTEM MODE
2410  */
2411
2412 int
2413 pmc_getrowdisp(int ri)
2414 {
2415         return pmc_pmcdisp[ri];
2416 }
2417
2418 /*
2419  * Check if a PMC at row index 'ri' can be allocated to the current
2420  * process.
2421  *
2422  * Allocation can fail if:
2423  *   - the current process is already being profiled by a PMC at index 'ri',
2424  *     attached to it via OP_PMCATTACH.
2425  *   - the current process has already allocated a PMC at index 'ri'
2426  *     via OP_ALLOCATE.
2427  */
2428
2429 static int
2430 pmc_can_allocate_rowindex(struct proc *p, unsigned int ri, int cpu)
2431 {
2432         enum pmc_mode mode;
2433         struct pmc *pm;
2434         struct pmc_owner *po;
2435         struct pmc_process *pp;
2436
2437         PMCDBG(PMC,ALR,1, "can-allocate-rowindex proc=%p (%d, %s) ri=%d "
2438             "cpu=%d", p, p->p_pid, p->p_comm, ri, cpu);
2439
2440         /*
2441          * We shouldn't have already allocated a process-mode PMC at
2442          * row index 'ri'.
2443          *
2444          * We shouldn't have allocated a system-wide PMC on the same
2445          * CPU and same RI.
2446          */
2447         if ((po = pmc_find_owner_descriptor(p)) != NULL)
2448                 LIST_FOREACH(pm, &po->po_pmcs, pm_next) {
2449                     if (PMC_TO_ROWINDEX(pm) == ri) {
2450                             mode = PMC_TO_MODE(pm);
2451                             if (PMC_IS_VIRTUAL_MODE(mode))
2452                                     return EEXIST;
2453                             if (PMC_IS_SYSTEM_MODE(mode) &&
2454                                 (int) PMC_TO_CPU(pm) == cpu)
2455                                     return EEXIST;
2456                     }
2457                 }
2458
2459         /*
2460          * We also shouldn't be the target of any PMC at this index
2461          * since otherwise a PMC_ATTACH to ourselves will fail.
2462          */
2463         if ((pp = pmc_find_process_descriptor(p, 0)) != NULL)
2464                 if (pp->pp_pmcs[ri].pp_pmc)
2465                         return EEXIST;
2466
2467         PMCDBG(PMC,ALR,2, "can-allocate-rowindex proc=%p (%d, %s) ri=%d ok",
2468             p, p->p_pid, p->p_comm, ri);
2469
2470         return 0;
2471 }
2472
2473 /*
2474  * Check if a given PMC at row index 'ri' can be currently used in
2475  * mode 'mode'.
2476  */
2477
2478 static int
2479 pmc_can_allocate_row(int ri, enum pmc_mode mode)
2480 {
2481         enum pmc_disp   disp;
2482
2483         sx_assert(&pmc_sx, SX_XLOCKED);
2484
2485         PMCDBG(PMC,ALR,1, "can-allocate-row ri=%d mode=%d", ri, mode);
2486
2487         if (PMC_IS_SYSTEM_MODE(mode))
2488                 disp = PMC_DISP_STANDALONE;
2489         else
2490                 disp = PMC_DISP_THREAD;
2491
2492         /*
2493          * check disposition for PMC row 'ri':
2494          *
2495          * Expected disposition         Row-disposition         Result
2496          *
2497          * STANDALONE                   STANDALONE or FREE      proceed
2498          * STANDALONE                   THREAD                  fail
2499          * THREAD                       THREAD or FREE          proceed
2500          * THREAD                       STANDALONE              fail
2501          */
2502
2503         if (!PMC_ROW_DISP_IS_FREE(ri) &&
2504             !(disp == PMC_DISP_THREAD && PMC_ROW_DISP_IS_THREAD(ri)) &&
2505             !(disp == PMC_DISP_STANDALONE && PMC_ROW_DISP_IS_STANDALONE(ri)))
2506                 return EBUSY;
2507
2508         /*
2509          * All OK
2510          */
2511
2512         PMCDBG(PMC,ALR,2, "can-allocate-row ri=%d mode=%d ok", ri, mode);
2513
2514         return 0;
2515
2516 }
2517
2518 /*
2519  * Find a PMC descriptor with user handle 'pmcid' for thread 'td'.
2520  */
2521
2522 static struct pmc *
2523 pmc_find_pmc_descriptor_in_process(struct pmc_owner *po, pmc_id_t pmcid)
2524 {
2525         struct pmc *pm;
2526
2527         KASSERT(PMC_ID_TO_ROWINDEX(pmcid) < md->pmd_npmc,
2528             ("[pmc,%d] Illegal pmc index %d (max %d)", __LINE__,
2529                 PMC_ID_TO_ROWINDEX(pmcid), md->pmd_npmc));
2530
2531         LIST_FOREACH(pm, &po->po_pmcs, pm_next)
2532             if (pm->pm_id == pmcid)
2533                     return pm;
2534
2535         return NULL;
2536 }
2537
2538 static int
2539 pmc_find_pmc(pmc_id_t pmcid, struct pmc **pmc)
2540 {
2541
2542         struct pmc *pm;
2543         struct pmc_owner *po;
2544
2545         PMCDBG(PMC,FND,1, "find-pmc id=%d", pmcid);
2546
2547         if ((po = pmc_find_owner_descriptor(curthread->td_proc)) == NULL)
2548                 return ESRCH;
2549
2550         if ((pm = pmc_find_pmc_descriptor_in_process(po, pmcid)) == NULL)
2551                 return EINVAL;
2552
2553         PMCDBG(PMC,FND,2, "find-pmc id=%d -> pmc=%p", pmcid, pm);
2554
2555         *pmc = pm;
2556         return 0;
2557 }
2558
2559 /*
2560  * Start a PMC.
2561  */
2562
2563 static int
2564 pmc_start(struct pmc *pm)
2565 {
2566         enum pmc_mode mode;
2567         struct pmc_owner *po;
2568         struct pmc_binding pb;
2569         struct pmc_classdep *pcd;
2570         int adjri, error, cpu, ri;
2571
2572         KASSERT(pm != NULL,
2573             ("[pmc,%d] null pm", __LINE__));
2574
2575         mode = PMC_TO_MODE(pm);
2576         ri   = PMC_TO_ROWINDEX(pm);
2577         pcd  = pmc_ri_to_classdep(md, ri, &adjri);
2578
2579         error = 0;
2580
2581         PMCDBG(PMC,OPS,1, "start pmc=%p mode=%d ri=%d", pm, mode, ri);
2582
2583         po = pm->pm_owner;
2584
2585         /*
2586          * Disallow PMCSTART if a logfile is required but has not been
2587          * configured yet.
2588          */
2589         if ((pm->pm_flags & PMC_F_NEEDS_LOGFILE) &&
2590             (po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)
2591                 return (EDOOFUS);       /* programming error */
2592
2593         /*
2594          * If this is a sampling mode PMC, log mapping information for
2595          * the kernel modules that are currently loaded.
2596          */
2597         if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
2598             pmc_log_kernel_mappings(pm);
2599
2600         if (PMC_IS_VIRTUAL_MODE(mode)) {
2601
2602                 /*
2603                  * If a PMCATTACH has never been done on this PMC,
2604                  * attach it to its owner process.
2605                  */
2606
2607                 if (LIST_EMPTY(&pm->pm_targets))
2608                         error = (pm->pm_flags & PMC_F_ATTACH_DONE) ? ESRCH :
2609                             pmc_attach_process(po->po_owner, pm);
2610
2611                 /*
2612                  * If the PMC is attached to its owner, then force a context
2613                  * switch to ensure that the MD state gets set correctly.
2614                  */
2615
2616                 if (error == 0) {
2617                         pm->pm_state = PMC_STATE_RUNNING;
2618                         if (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER)
2619                                 pmc_force_context_switch();
2620                 }
2621
2622                 return (error);
2623         }
2624
2625
2626         /*
2627          * A system-wide PMC.
2628          *
2629          * Add the owner to the global list if this is a system-wide
2630          * sampling PMC.
2631          */
2632
2633         if (mode == PMC_MODE_SS) {
2634                 if (po->po_sscount == 0) {
2635                         LIST_INSERT_HEAD(&pmc_ss_owners, po, po_ssnext);
2636                         atomic_add_rel_int(&pmc_ss_count, 1);
2637                         PMCDBG(PMC,OPS,1, "po=%p in global list", po);
2638                 }
2639                 po->po_sscount++;
2640
2641                 /*
2642                  * Log mapping information for all existing processes in the
2643                  * system.  Subsequent mappings are logged as they happen;
2644                  * see pmc_process_mmap().
2645                  */
2646                 if (po->po_logprocmaps == 0) {
2647                         pmc_log_all_process_mappings(po);
2648                         po->po_logprocmaps = 1;
2649                 }
2650         }
2651
2652         /*
2653          * Move to the CPU associated with this
2654          * PMC, and start the hardware.
2655          */
2656
2657         pmc_save_cpu_binding(&pb);
2658
2659         cpu = PMC_TO_CPU(pm);
2660
2661         if (!pmc_cpu_is_active(cpu))
2662                 return (ENXIO);
2663
2664         pmc_select_cpu(cpu);
2665
2666         /*
2667          * global PMCs are configured at allocation time
2668          * so write out the initial value and start the PMC.
2669          */
2670
2671         pm->pm_state = PMC_STATE_RUNNING;
2672
2673         critical_enter();
2674         if ((error = pcd->pcd_write_pmc(cpu, adjri,
2675                  PMC_IS_SAMPLING_MODE(mode) ?
2676                  pm->pm_sc.pm_reloadcount :
2677                  pm->pm_sc.pm_initial)) == 0)
2678                 error = pcd->pcd_start_pmc(cpu, adjri);
2679         critical_exit();
2680
2681         pmc_restore_cpu_binding(&pb);
2682
2683         return (error);
2684 }
2685
2686 /*
2687  * Stop a PMC.
2688  */
2689
2690 static int
2691 pmc_stop(struct pmc *pm)
2692 {
2693         struct pmc_owner *po;
2694         struct pmc_binding pb;
2695         struct pmc_classdep *pcd;
2696         int adjri, cpu, error, ri;
2697
2698         KASSERT(pm != NULL, ("[pmc,%d] null pmc", __LINE__));
2699
2700         PMCDBG(PMC,OPS,1, "stop pmc=%p mode=%d ri=%d", pm,
2701             PMC_TO_MODE(pm), PMC_TO_ROWINDEX(pm));
2702
2703         pm->pm_state = PMC_STATE_STOPPED;
2704
2705         /*
2706          * If the PMC is a virtual mode one, changing the state to
2707          * non-RUNNING is enough to ensure that the PMC never gets
2708          * scheduled.
2709          *
2710          * If this PMC is current running on a CPU, then it will
2711          * handled correctly at the time its target process is context
2712          * switched out.
2713          */
2714
2715         if (PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)))
2716                 return 0;
2717
2718         /*
2719          * A system-mode PMC.  Move to the CPU associated with
2720          * this PMC, and stop the hardware.  We update the
2721          * 'initial count' so that a subsequent PMCSTART will
2722          * resume counting from the current hardware count.
2723          */
2724
2725         pmc_save_cpu_binding(&pb);
2726
2727         cpu = PMC_TO_CPU(pm);
2728
2729         KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
2730             ("[pmc,%d] illegal cpu=%d", __LINE__, cpu));
2731
2732         if (!pmc_cpu_is_active(cpu))
2733                 return ENXIO;
2734
2735         pmc_select_cpu(cpu);
2736
2737         ri = PMC_TO_ROWINDEX(pm);
2738         pcd = pmc_ri_to_classdep(md, ri, &adjri);
2739
2740         critical_enter();
2741         if ((error = pcd->pcd_stop_pmc(cpu, adjri)) == 0)
2742                 error = pcd->pcd_read_pmc(cpu, adjri, &pm->pm_sc.pm_initial);
2743         critical_exit();
2744
2745         pmc_restore_cpu_binding(&pb);
2746
2747         po = pm->pm_owner;
2748
2749         /* remove this owner from the global list of SS PMC owners */
2750         if (PMC_TO_MODE(pm) == PMC_MODE_SS) {
2751                 po->po_sscount--;
2752                 if (po->po_sscount == 0) {
2753                         atomic_subtract_rel_int(&pmc_ss_count, 1);
2754                         LIST_REMOVE(po, po_ssnext);
2755                         PMCDBG(PMC,OPS,2,"po=%p removed from global list", po);
2756                 }
2757         }
2758
2759         return (error);
2760 }
2761
2762
2763 #ifdef  DEBUG
2764 static const char *pmc_op_to_name[] = {
2765 #undef  __PMC_OP
2766 #define __PMC_OP(N, D)  #N ,
2767         __PMC_OPS()
2768         NULL
2769 };
2770 #endif
2771
2772 /*
2773  * The syscall interface
2774  */
2775
2776 #define PMC_GET_SX_XLOCK(...) do {              \
2777         sx_xlock(&pmc_sx);                      \
2778         if (pmc_hook == NULL) {                 \
2779                 sx_xunlock(&pmc_sx);            \
2780                 return __VA_ARGS__;             \
2781         }                                       \
2782 } while (0)
2783
2784 #define PMC_DOWNGRADE_SX() do {                 \
2785         sx_downgrade(&pmc_sx);                  \
2786         is_sx_downgraded = 1;                   \
2787 } while (0)
2788
2789 static int
2790 pmc_syscall_handler(struct thread *td, void *syscall_args)
2791 {
2792         int error, is_sx_downgraded, is_sx_locked, op;
2793         struct pmc_syscall_args *c;
2794         void *arg;
2795
2796         PMC_GET_SX_XLOCK(ENOSYS);
2797
2798         DROP_GIANT();
2799
2800         is_sx_downgraded = 0;
2801         is_sx_locked = 1;
2802
2803         c = (struct pmc_syscall_args *) syscall_args;
2804
2805         op = c->pmop_code;
2806         arg = c->pmop_data;
2807
2808         PMCDBG(MOD,PMS,1, "syscall op=%d \"%s\" arg=%p", op,
2809             pmc_op_to_name[op], arg);
2810
2811         error = 0;
2812         atomic_add_int(&pmc_stats.pm_syscalls, 1);
2813
2814         switch(op)
2815         {
2816
2817
2818         /*
2819          * Configure a log file.
2820          *
2821          * XXX This OP will be reworked.
2822          */
2823
2824         case PMC_OP_CONFIGURELOG:
2825         {
2826                 struct proc *p;
2827                 struct pmc *pm;
2828                 struct pmc_owner *po;
2829                 struct pmc_op_configurelog cl;
2830
2831                 sx_assert(&pmc_sx, SX_XLOCKED);
2832
2833                 if ((error = copyin(arg, &cl, sizeof(cl))) != 0)
2834                         break;
2835
2836                 /* mark this process as owning a log file */
2837                 p = td->td_proc;
2838                 if ((po = pmc_find_owner_descriptor(p)) == NULL)
2839                         if ((po = pmc_allocate_owner_descriptor(p)) == NULL) {
2840                                 error = ENOMEM;
2841                                 break;
2842                         }
2843
2844                 /*
2845                  * If a valid fd was passed in, try to configure that,
2846                  * otherwise if 'fd' was less than zero and there was
2847                  * a log file configured, flush its buffers and
2848                  * de-configure it.
2849                  */
2850                 if (cl.pm_logfd >= 0) {
2851                         sx_xunlock(&pmc_sx);
2852                         is_sx_locked = 0;
2853                         error = pmclog_configure_log(md, po, cl.pm_logfd);
2854                 } else if (po->po_flags & PMC_PO_OWNS_LOGFILE) {
2855                         pmclog_process_closelog(po);
2856                         error = pmclog_close(po);
2857                         if (error == 0) {
2858                                 LIST_FOREACH(pm, &po->po_pmcs, pm_next)
2859                                     if (pm->pm_flags & PMC_F_NEEDS_LOGFILE &&
2860                                         pm->pm_state == PMC_STATE_RUNNING)
2861                                             pmc_stop(pm);
2862                                 error = pmclog_deconfigure_log(po);
2863                         }
2864                 } else
2865                         error = EINVAL;
2866
2867                 if (error)
2868                         break;
2869         }
2870         break;
2871
2872         /*
2873          * Flush a log file.
2874          */
2875
2876         case PMC_OP_FLUSHLOG:
2877         {
2878                 struct pmc_owner *po;
2879
2880                 sx_assert(&pmc_sx, SX_XLOCKED);
2881
2882                 if ((po = pmc_find_owner_descriptor(td->td_proc)) == NULL) {
2883                         error = EINVAL;
2884                         break;
2885                 }
2886
2887                 error = pmclog_flush(po);
2888         }
2889         break;
2890
2891         /*
2892          * Close a log file.
2893          */
2894
2895         case PMC_OP_CLOSELOG:
2896         {
2897                 struct pmc_owner *po;
2898
2899                 sx_assert(&pmc_sx, SX_XLOCKED);
2900
2901                 if ((po = pmc_find_owner_descriptor(td->td_proc)) == NULL) {
2902                         error = EINVAL;
2903                         break;
2904                 }
2905
2906                 error = pmclog_close(po);
2907         }
2908         break;
2909
2910         /*
2911          * Retrieve hardware configuration.
2912          */
2913
2914         case PMC_OP_GETCPUINFO: /* CPU information */
2915         {
2916                 struct pmc_op_getcpuinfo gci;
2917                 struct pmc_classinfo *pci;
2918                 struct pmc_classdep *pcd;
2919                 int cl;
2920
2921                 gci.pm_cputype = md->pmd_cputype;
2922                 gci.pm_ncpu    = pmc_cpu_max();
2923                 gci.pm_npmc    = md->pmd_npmc;
2924                 gci.pm_nclass  = md->pmd_nclass;
2925                 pci = gci.pm_classes;
2926                 pcd = md->pmd_classdep;
2927                 for (cl = 0; cl < md->pmd_nclass; cl++, pci++, pcd++) {
2928                         pci->pm_caps  = pcd->pcd_caps;
2929                         pci->pm_class = pcd->pcd_class;
2930                         pci->pm_width = pcd->pcd_width;
2931                         pci->pm_num   = pcd->pcd_num;
2932                 }
2933                 error = copyout(&gci, arg, sizeof(gci));
2934         }
2935         break;
2936
2937         /*
2938          * Retrieve soft events list.
2939          */
2940         case PMC_OP_GETDYNEVENTINFO:
2941         {
2942                 enum pmc_class                  cl;
2943                 enum pmc_event                  ev;
2944                 struct pmc_op_getdyneventinfo   *gei;
2945                 struct pmc_dyn_event_descr      dev;
2946                 struct pmc_soft                 *ps;
2947                 uint32_t                        nevent;
2948
2949                 sx_assert(&pmc_sx, SX_LOCKED);
2950
2951                 gei = (struct pmc_op_getdyneventinfo *) arg;
2952
2953                 if ((error = copyin(&gei->pm_class, &cl, sizeof(cl))) != 0)
2954                         break;
2955
2956                 /* Only SOFT class is dynamic. */
2957                 if (cl != PMC_CLASS_SOFT) {
2958                         error = EINVAL;
2959                         break;
2960                 }
2961
2962                 nevent = 0;
2963                 for (ev = PMC_EV_SOFT_FIRST; (int)ev <= PMC_EV_SOFT_LAST; ev++) {
2964                         ps = pmc_soft_ev_acquire(ev);
2965                         if (ps == NULL)
2966                                 continue;
2967                         bcopy(&ps->ps_ev, &dev, sizeof(dev));
2968                         pmc_soft_ev_release(ps);
2969
2970                         error = copyout(&dev,
2971                             &gei->pm_events[nevent],
2972                             sizeof(struct pmc_dyn_event_descr));
2973                         if (error != 0)
2974                                 break;
2975                         nevent++;
2976                 }
2977                 if (error != 0)
2978                         break;
2979
2980                 error = copyout(&nevent, &gei->pm_nevent,
2981                     sizeof(nevent));
2982         }
2983         break;
2984
2985         /*
2986          * Get module statistics
2987          */
2988
2989         case PMC_OP_GETDRIVERSTATS:
2990         {
2991                 struct pmc_op_getdriverstats gms;
2992
2993                 bcopy(&pmc_stats, &gms, sizeof(gms));
2994                 error = copyout(&gms, arg, sizeof(gms));
2995         }
2996         break;
2997
2998
2999         /*
3000          * Retrieve module version number
3001          */
3002
3003         case PMC_OP_GETMODULEVERSION:
3004         {
3005                 uint32_t cv, modv;
3006
3007                 /* retrieve the client's idea of the ABI version */
3008                 if ((error = copyin(arg, &cv, sizeof(uint32_t))) != 0)
3009                         break;
3010                 /* don't service clients newer than our driver */
3011                 modv = PMC_VERSION;
3012                 if ((cv & 0xFFFF0000) > (modv & 0xFFFF0000)) {
3013                         error = EPROGMISMATCH;
3014                         break;
3015                 }
3016                 error = copyout(&modv, arg, sizeof(int));
3017         }
3018         break;
3019
3020
3021         /*
3022          * Retrieve the state of all the PMCs on a given
3023          * CPU.
3024          */
3025
3026         case PMC_OP_GETPMCINFO:
3027         {
3028                 int ari;
3029                 struct pmc *pm;
3030                 size_t pmcinfo_size;
3031                 uint32_t cpu, n, npmc;
3032                 struct pmc_owner *po;
3033                 struct pmc_binding pb;
3034                 struct pmc_classdep *pcd;
3035                 struct pmc_info *p, *pmcinfo;
3036                 struct pmc_op_getpmcinfo *gpi;
3037
3038                 PMC_DOWNGRADE_SX();
3039
3040                 gpi = (struct pmc_op_getpmcinfo *) arg;
3041
3042                 if ((error = copyin(&gpi->pm_cpu, &cpu, sizeof(cpu))) != 0)
3043                         break;
3044
3045                 if (cpu >= pmc_cpu_max()) {
3046                         error = EINVAL;
3047                         break;
3048                 }
3049
3050                 if (!pmc_cpu_is_active(cpu)) {
3051                         error = ENXIO;
3052                         break;
3053                 }
3054
3055                 /* switch to CPU 'cpu' */
3056                 pmc_save_cpu_binding(&pb);
3057                 pmc_select_cpu(cpu);
3058
3059                 npmc = md->pmd_npmc;
3060
3061                 pmcinfo_size = npmc * sizeof(struct pmc_info);
3062                 pmcinfo = malloc(pmcinfo_size, M_PMC, M_WAITOK);
3063
3064                 p = pmcinfo;
3065
3066                 for (n = 0; n < md->pmd_npmc; n++, p++) {
3067
3068                         pcd = pmc_ri_to_classdep(md, n, &ari);
3069
3070                         KASSERT(pcd != NULL,
3071                             ("[pmc,%d] null pcd ri=%d", __LINE__, n));
3072
3073                         if ((error = pcd->pcd_describe(cpu, ari, p, &pm)) != 0)
3074                                 break;
3075
3076                         if (PMC_ROW_DISP_IS_STANDALONE(n))
3077                                 p->pm_rowdisp = PMC_DISP_STANDALONE;
3078                         else if (PMC_ROW_DISP_IS_THREAD(n))
3079                                 p->pm_rowdisp = PMC_DISP_THREAD;
3080                         else
3081                                 p->pm_rowdisp = PMC_DISP_FREE;
3082
3083                         p->pm_ownerpid = -1;
3084
3085                         if (pm == NULL) /* no PMC associated */
3086                                 continue;
3087
3088                         po = pm->pm_owner;
3089
3090                         KASSERT(po->po_owner != NULL,
3091                             ("[pmc,%d] pmc_owner had a null proc pointer",
3092                                 __LINE__));
3093
3094                         p->pm_ownerpid = po->po_owner->p_pid;
3095                         p->pm_mode     = PMC_TO_MODE(pm);
3096                         p->pm_event    = pm->pm_event;
3097                         p->pm_flags    = pm->pm_flags;
3098
3099                         if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
3100                                 p->pm_reloadcount =
3101                                     pm->pm_sc.pm_reloadcount;
3102                 }
3103
3104                 pmc_restore_cpu_binding(&pb);
3105
3106                 /* now copy out the PMC info collected */
3107                 if (error == 0)
3108                         error = copyout(pmcinfo, &gpi->pm_pmcs, pmcinfo_size);
3109
3110                 free(pmcinfo, M_PMC);
3111         }
3112         break;
3113
3114
3115         /*
3116          * Set the administrative state of a PMC.  I.e. whether
3117          * the PMC is to be used or not.
3118          */
3119
3120         case PMC_OP_PMCADMIN:
3121         {
3122                 int cpu, ri;
3123                 enum pmc_state request;
3124                 struct pmc_cpu *pc;
3125                 struct pmc_hw *phw;
3126                 struct pmc_op_pmcadmin pma;
3127                 struct pmc_binding pb;
3128
3129                 sx_assert(&pmc_sx, SX_XLOCKED);
3130
3131                 KASSERT(td == curthread,
3132                     ("[pmc,%d] td != curthread", __LINE__));
3133
3134                 error = priv_check(td, PRIV_PMC_MANAGE);
3135                 if (error)
3136                         break;
3137
3138                 if ((error = copyin(arg, &pma, sizeof(pma))) != 0)
3139                         break;
3140
3141                 cpu = pma.pm_cpu;
3142
3143                 if (cpu < 0 || cpu >= (int) pmc_cpu_max()) {
3144                         error = EINVAL;
3145                         break;
3146                 }
3147
3148                 if (!pmc_cpu_is_active(cpu)) {
3149                         error = ENXIO;
3150                         break;
3151                 }
3152
3153                 request = pma.pm_state;
3154
3155                 if (request != PMC_STATE_DISABLED &&
3156                     request != PMC_STATE_FREE) {
3157                         error = EINVAL;
3158                         break;
3159                 }
3160
3161                 ri = pma.pm_pmc; /* pmc id == row index */
3162                 if (ri < 0 || ri >= (int) md->pmd_npmc) {
3163                         error = EINVAL;
3164                         break;
3165                 }
3166
3167                 /*
3168                  * We can't disable a PMC with a row-index allocated
3169                  * for process virtual PMCs.
3170                  */
3171
3172                 if (PMC_ROW_DISP_IS_THREAD(ri) &&
3173                     request == PMC_STATE_DISABLED) {
3174                         error = EBUSY;
3175                         break;
3176                 }
3177
3178                 /*
3179                  * otherwise, this PMC on this CPU is either free or
3180                  * in system-wide mode.
3181                  */
3182
3183                 pmc_save_cpu_binding(&pb);
3184                 pmc_select_cpu(cpu);
3185
3186                 pc  = pmc_pcpu[cpu];
3187                 phw = pc->pc_hwpmcs[ri];
3188
3189                 /*
3190                  * XXX do we need some kind of 'forced' disable?
3191                  */
3192
3193                 if (phw->phw_pmc == NULL) {
3194                         if (request == PMC_STATE_DISABLED &&
3195                             (phw->phw_state & PMC_PHW_FLAG_IS_ENABLED)) {
3196                                 phw->phw_state &= ~PMC_PHW_FLAG_IS_ENABLED;
3197                                 PMC_MARK_ROW_STANDALONE(ri);
3198                         } else if (request == PMC_STATE_FREE &&
3199                             (phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) == 0) {
3200                                 phw->phw_state |=  PMC_PHW_FLAG_IS_ENABLED;
3201                                 PMC_UNMARK_ROW_STANDALONE(ri);
3202                         }
3203                         /* other cases are a no-op */
3204                 } else
3205                         error = EBUSY;
3206
3207                 pmc_restore_cpu_binding(&pb);
3208         }
3209         break;
3210
3211
3212         /*
3213          * Allocate a PMC.
3214          */
3215
3216         case PMC_OP_PMCALLOCATE:
3217         {
3218                 int adjri, n;
3219                 u_int cpu;
3220                 uint32_t caps;
3221                 struct pmc *pmc;
3222                 enum pmc_mode mode;
3223                 struct pmc_hw *phw;
3224                 struct pmc_binding pb;
3225                 struct pmc_classdep *pcd;
3226                 struct pmc_op_pmcallocate pa;
3227
3228                 if ((error = copyin(arg, &pa, sizeof(pa))) != 0)
3229                         break;
3230
3231                 caps = pa.pm_caps;
3232                 mode = pa.pm_mode;
3233                 cpu  = pa.pm_cpu;
3234
3235                 if ((mode != PMC_MODE_SS  &&  mode != PMC_MODE_SC  &&
3236                      mode != PMC_MODE_TS  &&  mode != PMC_MODE_TC) ||
3237                     (cpu != (u_int) PMC_CPU_ANY && cpu >= pmc_cpu_max())) {
3238                         error = EINVAL;
3239                         break;
3240                 }
3241
3242                 /*
3243                  * Virtual PMCs should only ask for a default CPU.
3244                  * System mode PMCs need to specify a non-default CPU.
3245                  */
3246
3247                 if ((PMC_IS_VIRTUAL_MODE(mode) && cpu != (u_int) PMC_CPU_ANY) ||
3248                     (PMC_IS_SYSTEM_MODE(mode) && cpu == (u_int) PMC_CPU_ANY)) {
3249                         error = EINVAL;
3250                         break;
3251                 }
3252
3253                 /*
3254                  * Check that an inactive CPU is not being asked for.
3255                  */
3256
3257                 if (PMC_IS_SYSTEM_MODE(mode) && !pmc_cpu_is_active(cpu)) {
3258                         error = ENXIO;
3259                         break;
3260                 }
3261
3262                 /*
3263                  * Refuse an allocation for a system-wide PMC if this
3264                  * process has been jailed, or if this process lacks
3265                  * super-user credentials and the sysctl tunable
3266                  * 'security.bsd.unprivileged_syspmcs' is zero.
3267                  */
3268
3269                 if (PMC_IS_SYSTEM_MODE(mode)) {
3270                         if (jailed(curthread->td_ucred)) {
3271                                 error = EPERM;
3272                                 break;
3273                         }
3274                         if (!pmc_unprivileged_syspmcs) {
3275                                 error = priv_check(curthread,
3276                                     PRIV_PMC_SYSTEM);
3277                                 if (error)
3278                                         break;
3279                         }
3280                 }
3281
3282                 /*
3283                  * Look for valid values for 'pm_flags'
3284                  */
3285
3286                 if ((pa.pm_flags & ~(PMC_F_DESCENDANTS | PMC_F_LOG_PROCCSW |
3287                     PMC_F_LOG_PROCEXIT | PMC_F_CALLCHAIN)) != 0) {
3288                         error = EINVAL;
3289                         break;
3290                 }
3291
3292                 /* process logging options are not allowed for system PMCs */
3293                 if (PMC_IS_SYSTEM_MODE(mode) && (pa.pm_flags &
3294                     (PMC_F_LOG_PROCCSW | PMC_F_LOG_PROCEXIT))) {
3295                         error = EINVAL;
3296                         break;
3297                 }
3298
3299                 /*
3300                  * All sampling mode PMCs need to be able to interrupt the
3301                  * CPU.
3302                  */
3303                 if (PMC_IS_SAMPLING_MODE(mode))
3304                         caps |= PMC_CAP_INTERRUPT;
3305
3306                 /* A valid class specifier should have been passed in. */
3307                 for (n = 0; n < md->pmd_nclass; n++)
3308                         if (md->pmd_classdep[n].pcd_class == pa.pm_class)
3309                                 break;
3310                 if (n == md->pmd_nclass) {
3311                         error = EINVAL;
3312                         break;
3313                 }
3314
3315                 /* The requested PMC capabilities should be feasible. */
3316                 if ((md->pmd_classdep[n].pcd_caps & caps) != caps) {
3317                         error = EOPNOTSUPP;
3318                         break;
3319                 }
3320
3321                 PMCDBG(PMC,ALL,2, "event=%d caps=0x%x mode=%d cpu=%d",
3322                     pa.pm_ev, caps, mode, cpu);
3323
3324                 pmc = pmc_allocate_pmc_descriptor();
3325                 pmc->pm_id    = PMC_ID_MAKE_ID(cpu,pa.pm_mode,pa.pm_class,
3326                     PMC_ID_INVALID);
3327                 pmc->pm_event = pa.pm_ev;
3328                 pmc->pm_state = PMC_STATE_FREE;
3329                 pmc->pm_caps  = caps;
3330                 pmc->pm_flags = pa.pm_flags;
3331
3332                 /* switch thread to CPU 'cpu' */
3333                 pmc_save_cpu_binding(&pb);
3334
3335 #define PMC_IS_SHAREABLE_PMC(cpu, n)                            \
3336         (pmc_pcpu[(cpu)]->pc_hwpmcs[(n)]->phw_state &           \
3337          PMC_PHW_FLAG_IS_SHAREABLE)
3338 #define PMC_IS_UNALLOCATED(cpu, n)                              \
3339         (pmc_pcpu[(cpu)]->pc_hwpmcs[(n)]->phw_pmc == NULL)
3340
3341                 if (PMC_IS_SYSTEM_MODE(mode)) {
3342                         pmc_select_cpu(cpu);
3343                         for (n = 0; n < (int) md->pmd_npmc; n++) {
3344                                 pcd = pmc_ri_to_classdep(md, n, &adjri);
3345                                 if (pmc_can_allocate_row(n, mode) == 0 &&
3346                                     pmc_can_allocate_rowindex(
3347                                             curthread->td_proc, n, cpu) == 0 &&
3348                                     (PMC_IS_UNALLOCATED(cpu, n) ||
3349                                      PMC_IS_SHAREABLE_PMC(cpu, n)) &&
3350                                     pcd->pcd_allocate_pmc(cpu, adjri, pmc,
3351                                         &pa) == 0)
3352                                         break;
3353                         }
3354                 } else {
3355                         /* Process virtual mode */
3356                         for (n = 0; n < (int) md->pmd_npmc; n++) {
3357                                 pcd = pmc_ri_to_classdep(md, n, &adjri);
3358                                 if (pmc_can_allocate_row(n, mode) == 0 &&
3359                                     pmc_can_allocate_rowindex(
3360                                             curthread->td_proc, n,
3361                                             PMC_CPU_ANY) == 0 &&
3362                                     pcd->pcd_allocate_pmc(curthread->td_oncpu,
3363                                         adjri, pmc, &pa) == 0)
3364                                         break;
3365                         }
3366                 }
3367
3368 #undef  PMC_IS_UNALLOCATED
3369 #undef  PMC_IS_SHAREABLE_PMC
3370
3371                 pmc_restore_cpu_binding(&pb);
3372
3373                 if (n == (int) md->pmd_npmc) {
3374                         pmc_destroy_pmc_descriptor(pmc);
3375                         free(pmc, M_PMC);
3376                         pmc = NULL;
3377                         error = EINVAL;
3378                         break;
3379                 }
3380
3381                 /* Fill in the correct value in the ID field */
3382                 pmc->pm_id = PMC_ID_MAKE_ID(cpu,mode,pa.pm_class,n);
3383
3384                 PMCDBG(PMC,ALL,2, "ev=%d class=%d mode=%d n=%d -> pmcid=%x",
3385                     pmc->pm_event, pa.pm_class, mode, n, pmc->pm_id);
3386
3387                 /* Process mode PMCs with logging enabled need log files */
3388                 if (pmc->pm_flags & (PMC_F_LOG_PROCEXIT | PMC_F_LOG_PROCCSW))
3389                         pmc->pm_flags |= PMC_F_NEEDS_LOGFILE;
3390
3391                 /* All system mode sampling PMCs require a log file */
3392                 if (PMC_IS_SAMPLING_MODE(mode) && PMC_IS_SYSTEM_MODE(mode))
3393                         pmc->pm_flags |= PMC_F_NEEDS_LOGFILE;
3394
3395                 /*
3396                  * Configure global pmc's immediately
3397                  */
3398
3399                 if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pmc))) {
3400
3401                         pmc_save_cpu_binding(&pb);
3402                         pmc_select_cpu(cpu);
3403
3404                         phw = pmc_pcpu[cpu]->pc_hwpmcs[n];
3405                         pcd = pmc_ri_to_classdep(md, n, &adjri);
3406
3407                         if ((phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) == 0 ||
3408                             (error = pcd->pcd_config_pmc(cpu, adjri, pmc)) != 0) {
3409                                 (void) pcd->pcd_release_pmc(cpu, adjri, pmc);
3410                                 pmc_destroy_pmc_descriptor(pmc);
3411                                 free(pmc, M_PMC);
3412                                 pmc = NULL;
3413                                 pmc_restore_cpu_binding(&pb);
3414                                 error = EPERM;
3415                                 break;
3416                         }
3417
3418                         pmc_restore_cpu_binding(&pb);
3419                 }
3420
3421                 pmc->pm_state    = PMC_STATE_ALLOCATED;
3422
3423                 /*
3424                  * mark row disposition
3425                  */
3426
3427                 if (PMC_IS_SYSTEM_MODE(mode))
3428                         PMC_MARK_ROW_STANDALONE(n);
3429                 else
3430                         PMC_MARK_ROW_THREAD(n);
3431
3432                 /*
3433                  * Register this PMC with the current thread as its owner.
3434                  */
3435
3436                 if ((error =
3437                     pmc_register_owner(curthread->td_proc, pmc)) != 0) {
3438                         pmc_release_pmc_descriptor(pmc);
3439                         free(pmc, M_PMC);
3440                         pmc = NULL;
3441                         break;
3442                 }
3443
3444                 /*
3445                  * Return the allocated index.
3446                  */
3447
3448                 pa.pm_pmcid = pmc->pm_id;
3449
3450                 error = copyout(&pa, arg, sizeof(pa));
3451         }
3452         break;
3453
3454
3455         /*
3456          * Attach a PMC to a process.
3457          */
3458
3459         case PMC_OP_PMCATTACH:
3460         {
3461                 struct pmc *pm;
3462                 struct proc *p;
3463                 struct pmc_op_pmcattach a;
3464
3465                 sx_assert(&pmc_sx, SX_XLOCKED);
3466
3467                 if ((error = copyin(arg, &a, sizeof(a))) != 0)
3468                         break;
3469
3470                 if (a.pm_pid < 0) {
3471                         error = EINVAL;
3472                         break;
3473                 } else if (a.pm_pid == 0)
3474                         a.pm_pid = td->td_proc->p_pid;
3475
3476                 if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
3477                         break;
3478
3479                 if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm))) {
3480                         error = EINVAL;
3481                         break;
3482                 }
3483
3484                 /* PMCs may be (re)attached only when allocated or stopped */
3485                 if (pm->pm_state == PMC_STATE_RUNNING) {
3486                         error = EBUSY;
3487                         break;
3488                 } else if (pm->pm_state != PMC_STATE_ALLOCATED &&
3489                     pm->pm_state != PMC_STATE_STOPPED) {
3490                         error = EINVAL;
3491                         break;
3492                 }
3493
3494                 /* lookup pid */
3495                 if ((p = pfind(a.pm_pid)) == NULL) {
3496                         error = ESRCH;
3497                         break;
3498                 }
3499
3500                 /*
3501                  * Ignore processes that are working on exiting.
3502                  */
3503                 if (p->p_flag & P_WEXIT) {
3504                         error = ESRCH;
3505                         PROC_UNLOCK(p); /* pfind() returns a locked process */
3506                         break;
3507                 }
3508
3509                 /*
3510                  * we are allowed to attach a PMC to a process if
3511                  * we can debug it.
3512                  */
3513                 error = p_candebug(curthread, p);
3514
3515                 PROC_UNLOCK(p);
3516
3517                 if (error == 0)
3518                         error = pmc_attach_process(p, pm);
3519         }
3520         break;
3521
3522
3523         /*
3524          * Detach an attached PMC from a process.
3525          */
3526
3527         case PMC_OP_PMCDETACH:
3528         {
3529                 struct pmc *pm;
3530                 struct proc *p;
3531                 struct pmc_op_pmcattach a;
3532
3533                 if ((error = copyin(arg, &a, sizeof(a))) != 0)
3534                         break;
3535
3536                 if (a.pm_pid < 0) {
3537                         error = EINVAL;
3538                         break;
3539                 } else if (a.pm_pid == 0)
3540                         a.pm_pid = td->td_proc->p_pid;
3541
3542                 if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
3543                         break;
3544
3545                 if ((p = pfind(a.pm_pid)) == NULL) {
3546                         error = ESRCH;
3547                         break;
3548                 }
3549
3550                 /*
3551                  * Treat processes that are in the process of exiting
3552                  * as if they were not present.
3553                  */
3554
3555                 if (p->p_flag & P_WEXIT)
3556                         error = ESRCH;
3557
3558                 PROC_UNLOCK(p); /* pfind() returns a locked process */
3559
3560                 if (error == 0)
3561                         error = pmc_detach_process(p, pm);
3562         }
3563         break;
3564
3565
3566         /*
3567          * Retrieve the MSR number associated with the counter
3568          * 'pmc_id'.  This allows processes to directly use RDPMC
3569          * instructions to read their PMCs, without the overhead of a
3570          * system call.
3571          */
3572
3573         case PMC_OP_PMCGETMSR:
3574         {
3575                 int adjri, ri;
3576                 struct pmc *pm;
3577                 struct pmc_target *pt;
3578                 struct pmc_op_getmsr gm;
3579                 struct pmc_classdep *pcd;
3580
3581                 PMC_DOWNGRADE_SX();
3582
3583                 if ((error = copyin(arg, &gm, sizeof(gm))) != 0)
3584                         break;
3585
3586                 if ((error = pmc_find_pmc(gm.pm_pmcid, &pm)) != 0)
3587                         break;
3588
3589                 /*
3590                  * The allocated PMC has to be a process virtual PMC,
3591                  * i.e., of type MODE_T[CS].  Global PMCs can only be
3592                  * read using the PMCREAD operation since they may be
3593                  * allocated on a different CPU than the one we could
3594                  * be running on at the time of the RDPMC instruction.
3595                  *
3596                  * The GETMSR operation is not allowed for PMCs that
3597                  * are inherited across processes.
3598                  */
3599
3600                 if (!PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)) ||
3601                     (pm->pm_flags & PMC_F_DESCENDANTS)) {
3602                         error = EINVAL;
3603                         break;
3604                 }
3605
3606                 /*
3607                  * It only makes sense to use a RDPMC (or its
3608                  * equivalent instruction on non-x86 architectures) on
3609                  * a process that has allocated and attached a PMC to
3610                  * itself.  Conversely the PMC is only allowed to have
3611                  * one process attached to it -- its owner.
3612                  */
3613
3614                 if ((pt = LIST_FIRST(&pm->pm_targets)) == NULL ||
3615                     LIST_NEXT(pt, pt_next) != NULL ||
3616                     pt->pt_process->pp_proc != pm->pm_owner->po_owner) {
3617                         error = EINVAL;
3618                         break;
3619                 }
3620
3621                 ri = PMC_TO_ROWINDEX(pm);
3622                 pcd = pmc_ri_to_classdep(md, ri, &adjri);
3623
3624                 /* PMC class has no 'GETMSR' support */
3625                 if (pcd->pcd_get_msr == NULL) {
3626                         error = ENOSYS;
3627                         break;
3628                 }
3629
3630                 if ((error = (*pcd->pcd_get_msr)(adjri, &gm.pm_msr)) < 0)
3631                         break;
3632
3633                 if ((error = copyout(&gm, arg, sizeof(gm))) < 0)
3634                         break;
3635
3636                 /*
3637                  * Mark our process as using MSRs.  Update machine
3638                  * state using a forced context switch.
3639                  */
3640
3641                 pt->pt_process->pp_flags |= PMC_PP_ENABLE_MSR_ACCESS;
3642                 pmc_force_context_switch();
3643
3644         }
3645         break;
3646
3647         /*
3648          * Release an allocated PMC
3649          */
3650
3651         case PMC_OP_PMCRELEASE:
3652         {
3653                 pmc_id_t pmcid;
3654                 struct pmc *pm;
3655                 struct pmc_owner *po;
3656                 struct pmc_op_simple sp;
3657
3658                 /*
3659                  * Find PMC pointer for the named PMC.
3660                  *
3661                  * Use pmc_release_pmc_descriptor() to switch off the
3662                  * PMC, remove all its target threads, and remove the
3663                  * PMC from its owner's list.
3664                  *
3665                  * Remove the owner record if this is the last PMC
3666                  * owned.
3667                  *
3668                  * Free up space.
3669                  */
3670
3671                 if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
3672                         break;
3673
3674                 pmcid = sp.pm_pmcid;
3675
3676                 if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
3677                         break;
3678
3679                 po = pm->pm_owner;
3680                 pmc_release_pmc_descriptor(pm);
3681                 pmc_maybe_remove_owner(po);
3682
3683                 free(pm, M_PMC);
3684         }
3685         break;
3686
3687
3688         /*
3689          * Read and/or write a PMC.
3690          */
3691
3692         case PMC_OP_PMCRW:
3693         {
3694                 int adjri;
3695                 struct pmc *pm;
3696                 uint32_t cpu, ri;
3697                 pmc_value_t oldvalue;
3698                 struct pmc_binding pb;
3699                 struct pmc_op_pmcrw prw;
3700                 struct pmc_classdep *pcd;
3701                 struct pmc_op_pmcrw *pprw;
3702
3703                 PMC_DOWNGRADE_SX();
3704
3705                 if ((error = copyin(arg, &prw, sizeof(prw))) != 0)
3706                         break;
3707
3708                 ri = 0;
3709                 PMCDBG(PMC,OPS,1, "rw id=%d flags=0x%x", prw.pm_pmcid,
3710                     prw.pm_flags);
3711
3712                 /* must have at least one flag set */
3713                 if ((prw.pm_flags & (PMC_F_OLDVALUE|PMC_F_NEWVALUE)) == 0) {
3714                         error = EINVAL;
3715                         break;
3716                 }
3717
3718                 /* locate pmc descriptor */
3719                 if ((error = pmc_find_pmc(prw.pm_pmcid, &pm)) != 0)
3720                         break;
3721
3722                 /* Can't read a PMC that hasn't been started. */
3723                 if (pm->pm_state != PMC_STATE_ALLOCATED &&
3724                     pm->pm_state != PMC_STATE_STOPPED &&
3725                     pm->pm_state != PMC_STATE_RUNNING) {
3726                         error = EINVAL;
3727                         break;
3728                 }
3729
3730                 /* writing a new value is allowed only for 'STOPPED' pmcs */
3731                 if (pm->pm_state == PMC_STATE_RUNNING &&
3732                     (prw.pm_flags & PMC_F_NEWVALUE)) {
3733                         error = EBUSY;
3734                         break;
3735                 }
3736
3737                 if (PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm))) {
3738
3739                         /*
3740                          * If this PMC is attached to its owner (i.e.,
3741                          * the process requesting this operation) and
3742                          * is running, then attempt to get an
3743                          * upto-date reading from hardware for a READ.
3744                          * Writes are only allowed when the PMC is
3745                          * stopped, so only update the saved value
3746                          * field.
3747                          *
3748                          * If the PMC is not running, or is not
3749                          * attached to its owner, read/write to the
3750                          * savedvalue field.
3751                          */
3752
3753                         ri = PMC_TO_ROWINDEX(pm);
3754                         pcd = pmc_ri_to_classdep(md, ri, &adjri);
3755
3756                         mtx_pool_lock_spin(pmc_mtxpool, pm);
3757                         cpu = curthread->td_oncpu;
3758
3759                         if (prw.pm_flags & PMC_F_OLDVALUE) {
3760                                 if ((pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) &&
3761                                     (pm->pm_state == PMC_STATE_RUNNING))
3762                                         error = (*pcd->pcd_read_pmc)(cpu, adjri,
3763                                             &oldvalue);
3764                                 else
3765                                         oldvalue = pm->pm_gv.pm_savedvalue;
3766                         }
3767                         if (prw.pm_flags & PMC_F_NEWVALUE)
3768                                 pm->pm_gv.pm_savedvalue = prw.pm_value;
3769
3770                         mtx_pool_unlock_spin(pmc_mtxpool, pm);
3771
3772                 } else { /* System mode PMCs */
3773                         cpu = PMC_TO_CPU(pm);
3774                         ri  = PMC_TO_ROWINDEX(pm);
3775                         pcd = pmc_ri_to_classdep(md, ri, &adjri);
3776
3777                         if (!pmc_cpu_is_active(cpu)) {
3778                                 error = ENXIO;
3779                                 break;
3780                         }
3781
3782                         /* move this thread to CPU 'cpu' */
3783                         pmc_save_cpu_binding(&pb);
3784                         pmc_select_cpu(cpu);
3785
3786                         critical_enter();
3787                         /* save old value */
3788                         if (prw.pm_flags & PMC_F_OLDVALUE)
3789                                 if ((error = (*pcd->pcd_read_pmc)(cpu, adjri,
3790                                          &oldvalue)))
3791                                         goto error;
3792                         /* write out new value */
3793                         if (prw.pm_flags & PMC_F_NEWVALUE)
3794                                 error = (*pcd->pcd_write_pmc)(cpu, adjri,
3795                                     prw.pm_value);
3796                 error:
3797                         critical_exit();
3798                         pmc_restore_cpu_binding(&pb);
3799                         if (error)
3800                                 break;
3801                 }
3802
3803                 pprw = (struct pmc_op_pmcrw *) arg;
3804
3805 #ifdef  DEBUG
3806                 if (prw.pm_flags & PMC_F_NEWVALUE)
3807                         PMCDBG(PMC,OPS,2, "rw id=%d new %jx -> old %jx",
3808                             ri, prw.pm_value, oldvalue);
3809                 else if (prw.pm_flags & PMC_F_OLDVALUE)
3810                         PMCDBG(PMC,OPS,2, "rw id=%d -> old %jx", ri, oldvalue);
3811 #endif
3812
3813                 /* return old value if requested */
3814                 if (prw.pm_flags & PMC_F_OLDVALUE)
3815                         if ((error = copyout(&oldvalue, &pprw->pm_value,
3816                                  sizeof(prw.pm_value))))
3817                                 break;
3818
3819         }
3820         break;
3821
3822
3823         /*
3824          * Set the sampling rate for a sampling mode PMC and the
3825          * initial count for a counting mode PMC.
3826          */
3827
3828         case PMC_OP_PMCSETCOUNT:
3829         {
3830                 struct pmc *pm;
3831                 struct pmc_op_pmcsetcount sc;
3832
3833                 PMC_DOWNGRADE_SX();
3834
3835                 if ((error = copyin(arg, &sc, sizeof(sc))) != 0)
3836                         break;
3837
3838                 if ((error = pmc_find_pmc(sc.pm_pmcid, &pm)) != 0)
3839                         break;
3840
3841                 if (pm->pm_state == PMC_STATE_RUNNING) {
3842                         error = EBUSY;
3843                         break;
3844                 }
3845
3846                 if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
3847                         pm->pm_sc.pm_reloadcount = sc.pm_count;
3848                 else
3849                         pm->pm_sc.pm_initial = sc.pm_count;
3850         }
3851         break;
3852
3853
3854         /*
3855          * Start a PMC.
3856          */
3857
3858         case PMC_OP_PMCSTART:
3859         {
3860                 pmc_id_t pmcid;
3861                 struct pmc *pm;
3862                 struct pmc_op_simple sp;
3863
3864                 sx_assert(&pmc_sx, SX_XLOCKED);
3865
3866                 if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
3867                         break;
3868
3869                 pmcid = sp.pm_pmcid;
3870
3871                 if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
3872                         break;
3873
3874                 KASSERT(pmcid == pm->pm_id,
3875                     ("[pmc,%d] pmcid %x != id %x", __LINE__,
3876                         pm->pm_id, pmcid));
3877
3878                 if (pm->pm_state == PMC_STATE_RUNNING) /* already running */
3879                         break;
3880                 else if (pm->pm_state != PMC_STATE_STOPPED &&
3881                     pm->pm_state != PMC_STATE_ALLOCATED) {
3882                         error = EINVAL;
3883                         break;
3884                 }
3885
3886                 error = pmc_start(pm);
3887         }
3888         break;
3889
3890
3891         /*
3892          * Stop a PMC.
3893          */
3894
3895         case PMC_OP_PMCSTOP:
3896         {
3897                 pmc_id_t pmcid;
3898                 struct pmc *pm;
3899                 struct pmc_op_simple sp;
3900
3901                 PMC_DOWNGRADE_SX();
3902
3903                 if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
3904                         break;
3905
3906                 pmcid = sp.pm_pmcid;
3907
3908                 /*
3909                  * Mark the PMC as inactive and invoke the MD stop
3910                  * routines if needed.
3911                  */
3912
3913                 if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
3914                         break;
3915
3916                 KASSERT(pmcid == pm->pm_id,
3917                     ("[pmc,%d] pmc id %x != pmcid %x", __LINE__,
3918                         pm->pm_id, pmcid));
3919
3920                 if (pm->pm_state == PMC_STATE_STOPPED) /* already stopped */
3921                         break;
3922                 else if (pm->pm_state != PMC_STATE_RUNNING) {
3923                         error = EINVAL;
3924                         break;
3925                 }
3926
3927                 error = pmc_stop(pm);
3928         }
3929         break;
3930
3931
3932         /*
3933          * Write a user supplied value to the log file.
3934          */
3935
3936         case PMC_OP_WRITELOG:
3937         {
3938                 struct pmc_op_writelog wl;
3939                 struct pmc_owner *po;
3940
3941                 PMC_DOWNGRADE_SX();
3942
3943                 if ((error = copyin(arg, &wl, sizeof(wl))) != 0)
3944                         break;
3945
3946                 if ((po = pmc_find_owner_descriptor(td->td_proc)) == NULL) {
3947                         error = EINVAL;
3948                         break;
3949                 }
3950
3951                 if ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0) {
3952                         error = EINVAL;
3953                         break;
3954                 }
3955
3956                 error = pmclog_process_userlog(po, &wl);
3957         }
3958         break;
3959
3960
3961         default:
3962                 error = EINVAL;
3963                 break;
3964         }
3965
3966         if (is_sx_locked != 0) {
3967                 if (is_sx_downgraded)
3968                         sx_sunlock(&pmc_sx);
3969                 else
3970                         sx_xunlock(&pmc_sx);
3971         }
3972
3973         if (error)
3974                 atomic_add_int(&pmc_stats.pm_syscall_errors, 1);
3975
3976         PICKUP_GIANT();
3977
3978         return error;
3979 }
3980
3981 /*
3982  * Helper functions
3983  */
3984
3985
3986 /*
3987  * Mark the thread as needing callchain capture and post an AST.  The
3988  * actual callchain capture will be done in a context where it is safe
3989  * to take page faults.
3990  */
3991
3992 static void
3993 pmc_post_callchain_callback(void)
3994 {
3995         struct thread *td;
3996
3997         td = curthread;
3998
3999         /*
4000          * If there is multiple PMCs for the same interrupt ignore new post
4001          */
4002         if (td->td_pflags & TDP_CALLCHAIN)
4003                 return;
4004
4005         /*
4006          * Mark this thread as needing callchain capture.
4007          * `td->td_pflags' will be safe to touch because this thread
4008          * was in user space when it was interrupted.
4009          */
4010         td->td_pflags |= TDP_CALLCHAIN;
4011
4012         /*
4013          * Don't let this thread migrate between CPUs until callchain
4014          * capture completes.
4015          */
4016         sched_pin();
4017
4018         return;
4019 }
4020
4021 /*
4022  * Interrupt processing.
4023  *
4024  * Find a free slot in the per-cpu array of samples and capture the
4025  * current callchain there.  If a sample was successfully added, a bit
4026  * is set in mask 'pmc_cpumask' denoting that the DO_SAMPLES hook
4027  * needs to be invoked from the clock handler.
4028  *
4029  * This function is meant to be called from an NMI handler.  It cannot
4030  * use any of the locking primitives supplied by the OS.
4031  */
4032
4033 int
4034 pmc_process_interrupt(int cpu, int ring, struct pmc *pm, struct trapframe *tf,
4035     int inuserspace)
4036 {
4037         int error, callchaindepth;
4038         struct thread *td;
4039         struct pmc_sample *ps;
4040         struct pmc_samplebuffer *psb;
4041
4042         error = 0;
4043
4044         /*
4045          * Allocate space for a sample buffer.
4046          */
4047         psb = pmc_pcpu[cpu]->pc_sb[ring];
4048
4049         ps = psb->ps_write;
4050         if (ps->ps_nsamples) {  /* in use, reader hasn't caught up */
4051                 pm->pm_stalled = 1;
4052                 atomic_add_int(&pmc_stats.pm_intr_bufferfull, 1);
4053                 PMCDBG(SAM,INT,1,"(spc) cpu=%d pm=%p tf=%p um=%d wr=%d rd=%d",
4054                     cpu, pm, (void *) tf, inuserspace,
4055                     (int) (psb->ps_write - psb->ps_samples),
4056                     (int) (psb->ps_read - psb->ps_samples));
4057                 error = ENOMEM;
4058                 goto done;
4059         }
4060
4061
4062         /* Fill in entry. */
4063         PMCDBG(SAM,INT,1,"cpu=%d pm=%p tf=%p um=%d wr=%d rd=%d", cpu, pm,
4064             (void *) tf, inuserspace,
4065             (int) (psb->ps_write - psb->ps_samples),
4066             (int) (psb->ps_read - psb->ps_samples));
4067
4068         KASSERT(pm->pm_runcount >= 0,
4069             ("[pmc,%d] pm=%p runcount %d", __LINE__, (void *) pm,
4070                 pm->pm_runcount));
4071
4072         atomic_add_rel_int(&pm->pm_runcount, 1);        /* hold onto PMC */
4073
4074         ps->ps_pmc = pm;
4075         if ((td = curthread) && td->td_proc)
4076                 ps->ps_pid = td->td_proc->p_pid;
4077         else
4078                 ps->ps_pid = -1;
4079         ps->ps_cpu = cpu;
4080         ps->ps_td = td;
4081         ps->ps_flags = inuserspace ? PMC_CC_F_USERSPACE : 0;
4082
4083         callchaindepth = (pm->pm_flags & PMC_F_CALLCHAIN) ?
4084             pmc_callchaindepth : 1;
4085
4086         if (callchaindepth == 1)
4087                 ps->ps_pc[0] = PMC_TRAPFRAME_TO_PC(tf);
4088         else {
4089                 /*
4090                  * Kernel stack traversals can be done immediately,
4091                  * while we defer to an AST for user space traversals.
4092                  */
4093                 if (!inuserspace) {
4094                         callchaindepth =
4095                             pmc_save_kernel_callchain(ps->ps_pc,
4096                                 callchaindepth, tf);
4097                 } else {
4098                         pmc_post_callchain_callback();
4099                         callchaindepth = PMC_SAMPLE_INUSE;
4100                 }
4101         }
4102
4103         ps->ps_nsamples = callchaindepth;       /* mark entry as in use */
4104
4105         /* increment write pointer, modulo ring buffer size */
4106         ps++;
4107         if (ps == psb->ps_fence)
4108                 psb->ps_write = psb->ps_samples;
4109         else
4110                 psb->ps_write = ps;
4111
4112  done:
4113         /* mark CPU as needing processing */
4114         CPU_SET_ATOMIC(cpu, &pmc_cpumask);
4115
4116         return (error);
4117 }
4118
4119 /*
4120  * Capture a user call chain.  This function will be called from ast()
4121  * before control returns to userland and before the process gets
4122  * rescheduled.
4123  */
4124
4125 static void
4126 pmc_capture_user_callchain(int cpu, int ring, struct trapframe *tf)
4127 {
4128         int i;
4129         struct pmc *pm;
4130         struct thread *td;
4131         struct pmc_sample *ps;
4132         struct pmc_samplebuffer *psb;
4133 #ifdef  INVARIANTS
4134         int ncallchains;
4135 #endif
4136
4137         psb = pmc_pcpu[cpu]->pc_sb[ring];
4138         td = curthread;
4139
4140         KASSERT(td->td_pflags & TDP_CALLCHAIN,
4141             ("[pmc,%d] Retrieving callchain for thread that doesn't want it",
4142                 __LINE__));
4143
4144 #ifdef  INVARIANTS
4145         ncallchains = 0;
4146 #endif
4147
4148         /*
4149          * Iterate through all deferred callchain requests.
4150          */
4151
4152         ps = psb->ps_samples;
4153         for (i = 0; i < pmc_nsamples; i++, ps++) {
4154
4155                 if (ps->ps_nsamples != PMC_SAMPLE_INUSE)
4156                         continue;
4157                 if (ps->ps_td != td)
4158                         continue;
4159
4160                 KASSERT(ps->ps_cpu == cpu,
4161                     ("[pmc,%d] cpu mismatch ps_cpu=%d pcpu=%d", __LINE__,
4162                         ps->ps_cpu, PCPU_GET(cpuid)));
4163
4164                 pm = ps->ps_pmc;
4165
4166                 KASSERT(pm->pm_flags & PMC_F_CALLCHAIN,
4167                     ("[pmc,%d] Retrieving callchain for PMC that doesn't "
4168                         "want it", __LINE__));
4169
4170                 KASSERT(pm->pm_runcount > 0,
4171                     ("[pmc,%d] runcount %d", __LINE__, pm->pm_runcount));
4172
4173                 /*
4174                  * Retrieve the callchain and mark the sample buffer
4175                  * as 'processable' by the timer tick sweep code.
4176                  */
4177                 ps->ps_nsamples = pmc_save_user_callchain(ps->ps_pc,
4178                     pmc_callchaindepth, tf);
4179
4180 #ifdef  INVARIANTS
4181                 ncallchains++;
4182 #endif
4183         }
4184
4185         KASSERT(ncallchains > 0,
4186             ("[pmc,%d] cpu %d didn't find a sample to collect", __LINE__,
4187                 cpu));
4188
4189         KASSERT(td->td_pinned == 1,
4190             ("[pmc,%d] invalid td_pinned value", __LINE__));
4191         sched_unpin();  /* Can migrate safely now. */
4192
4193         return;
4194 }
4195
4196 /*
4197  * Process saved PC samples.
4198  */
4199
4200 static void
4201 pmc_process_samples(int cpu, int ring)
4202 {
4203         struct pmc *pm;
4204         int adjri, n;
4205         struct thread *td;
4206         struct pmc_owner *po;
4207         struct pmc_sample *ps;
4208         struct pmc_classdep *pcd;
4209         struct pmc_samplebuffer *psb;
4210
4211         KASSERT(PCPU_GET(cpuid) == cpu,
4212             ("[pmc,%d] not on the correct CPU pcpu=%d cpu=%d", __LINE__,
4213                 PCPU_GET(cpuid), cpu));
4214
4215         psb = pmc_pcpu[cpu]->pc_sb[ring];
4216
4217         for (n = 0; n < pmc_nsamples; n++) { /* bound on #iterations */
4218
4219                 ps = psb->ps_read;
4220                 if (ps->ps_nsamples == PMC_SAMPLE_FREE)
4221                         break;
4222
4223                 pm = ps->ps_pmc;
4224
4225                 KASSERT(pm->pm_runcount > 0,
4226                     ("[pmc,%d] pm=%p runcount %d", __LINE__, (void *) pm,
4227                         pm->pm_runcount));
4228
4229                 po = pm->pm_owner;
4230
4231                 KASSERT(PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)),
4232                     ("[pmc,%d] pmc=%p non-sampling mode=%d", __LINE__,
4233                         pm, PMC_TO_MODE(pm)));
4234
4235                 /* Ignore PMCs that have been switched off */
4236                 if (pm->pm_state != PMC_STATE_RUNNING)
4237                         goto entrydone;
4238
4239                 /* If there is a pending AST wait for completion */
4240                 if (ps->ps_nsamples == PMC_SAMPLE_INUSE) {
4241                         /* Need a rescan at a later time. */
4242                         CPU_SET_ATOMIC(cpu, &pmc_cpumask);
4243                         break;
4244                 }
4245
4246                 PMCDBG(SAM,OPS,1,"cpu=%d pm=%p n=%d fl=%x wr=%d rd=%d", cpu,
4247                     pm, ps->ps_nsamples, ps->ps_flags,
4248                     (int) (psb->ps_write - psb->ps_samples),
4249                     (int) (psb->ps_read - psb->ps_samples));
4250
4251                 /*
4252                  * If this is a process-mode PMC that is attached to
4253                  * its owner, and if the PC is in user mode, update
4254                  * profiling statistics like timer-based profiling
4255                  * would have done.
4256                  */
4257                 if (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) {
4258                         if (ps->ps_flags & PMC_CC_F_USERSPACE) {
4259                                 td = FIRST_THREAD_IN_PROC(po->po_owner);
4260                                 addupc_intr(td, ps->ps_pc[0], 1);
4261                         }
4262                         goto entrydone;
4263                 }
4264
4265                 /*
4266                  * Otherwise, this is either a sampling mode PMC that
4267                  * is attached to a different process than its owner,
4268                  * or a system-wide sampling PMC.  Dispatch a log
4269                  * entry to the PMC's owner process.
4270                  */
4271                 pmclog_process_callchain(pm, ps);
4272
4273         entrydone:
4274                 ps->ps_nsamples = 0; /* mark entry as free */
4275                 atomic_subtract_rel_int(&pm->pm_runcount, 1);
4276
4277                 /* increment read pointer, modulo sample size */
4278                 if (++ps == psb->ps_fence)
4279                         psb->ps_read = psb->ps_samples;
4280                 else
4281                         psb->ps_read = ps;
4282         }
4283
4284         atomic_add_int(&pmc_stats.pm_log_sweeps, 1);
4285
4286         /* Do not re-enable stalled PMCs if we failed to process any samples */
4287         if (n == 0)
4288                 return;
4289
4290         /*
4291          * Restart any stalled sampling PMCs on this CPU.
4292          *
4293          * If the NMI handler sets the pm_stalled field of a PMC after
4294          * the check below, we'll end up processing the stalled PMC at
4295          * the next hardclock tick.
4296          */
4297         for (n = 0; n < md->pmd_npmc; n++) {
4298                 pcd = pmc_ri_to_classdep(md, n, &adjri);
4299                 KASSERT(pcd != NULL,
4300                     ("[pmc,%d] null pcd ri=%d", __LINE__, n));
4301                 (void) (*pcd->pcd_get_config)(cpu,adjri,&pm);
4302
4303                 if (pm == NULL ||                        /* !cfg'ed */
4304                     pm->pm_state != PMC_STATE_RUNNING || /* !active */
4305                     !PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)) || /* !sampling */
4306                     pm->pm_stalled == 0) /* !stalled */
4307                         continue;
4308
4309                 pm->pm_stalled = 0;
4310                 (*pcd->pcd_start_pmc)(cpu, adjri);
4311         }
4312 }
4313
4314 /*
4315  * Event handlers.
4316  */
4317
4318 /*
4319  * Handle a process exit.
4320  *
4321  * Remove this process from all hash tables.  If this process
4322  * owned any PMCs, turn off those PMCs and deallocate them,
4323  * removing any associations with target processes.
4324  *
4325  * This function will be called by the last 'thread' of a
4326  * process.
4327  *
4328  * XXX This eventhandler gets called early in the exit process.
4329  * Consider using a 'hook' invocation from thread_exit() or equivalent
4330  * spot.  Another negative is that kse_exit doesn't seem to call
4331  * exit1() [??].
4332  *
4333  */
4334
4335 static void
4336 pmc_process_exit(void *arg __unused, struct proc *p)
4337 {
4338         struct pmc *pm;
4339         int adjri, cpu;
4340         unsigned int ri;
4341         int is_using_hwpmcs;
4342         struct pmc_owner *po;
4343         struct pmc_process *pp;
4344         struct pmc_classdep *pcd;
4345         pmc_value_t newvalue, tmp;
4346
4347         PROC_LOCK(p);
4348         is_using_hwpmcs = p->p_flag & P_HWPMC;
4349         PROC_UNLOCK(p);
4350
4351         /*
4352          * Log a sysexit event to all SS PMC owners.
4353          */
4354         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
4355             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
4356                     pmclog_process_sysexit(po, p->p_pid);
4357
4358         if (!is_using_hwpmcs)
4359                 return;
4360
4361         PMC_GET_SX_XLOCK();
4362         PMCDBG(PRC,EXT,1,"process-exit proc=%p (%d, %s)", p, p->p_pid,
4363             p->p_comm);
4364
4365         /*
4366          * Since this code is invoked by the last thread in an exiting
4367          * process, we would have context switched IN at some prior
4368          * point.  However, with PREEMPTION, kernel mode context
4369          * switches may happen any time, so we want to disable a
4370          * context switch OUT till we get any PMCs targetting this
4371          * process off the hardware.
4372          *
4373          * We also need to atomically remove this process'
4374          * entry from our target process hash table, using
4375          * PMC_FLAG_REMOVE.
4376          */
4377         PMCDBG(PRC,EXT,1, "process-exit proc=%p (%d, %s)", p, p->p_pid,
4378             p->p_comm);
4379
4380         critical_enter(); /* no preemption */
4381
4382         cpu = curthread->td_oncpu;
4383
4384         if ((pp = pmc_find_process_descriptor(p,
4385                  PMC_FLAG_REMOVE)) != NULL) {
4386
4387                 PMCDBG(PRC,EXT,2,
4388                     "process-exit proc=%p pmc-process=%p", p, pp);
4389
4390                 /*
4391                  * The exiting process could the target of
4392                  * some PMCs which will be running on
4393                  * currently executing CPU.
4394                  *
4395                  * We need to turn these PMCs off like we
4396                  * would do at context switch OUT time.
4397                  */
4398                 for (ri = 0; ri < md->pmd_npmc; ri++) {
4399
4400                         /*
4401                          * Pick up the pmc pointer from hardware
4402                          * state similar to the CSW_OUT code.
4403                          */
4404                         pm = NULL;
4405
4406                         pcd = pmc_ri_to_classdep(md, ri, &adjri);
4407
4408                         (void) (*pcd->pcd_get_config)(cpu, adjri, &pm);
4409
4410                         PMCDBG(PRC,EXT,2, "ri=%d pm=%p", ri, pm);
4411
4412                         if (pm == NULL ||
4413                             !PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)))
4414                                 continue;
4415
4416                         PMCDBG(PRC,EXT,2, "ppmcs[%d]=%p pm=%p "
4417                             "state=%d", ri, pp->pp_pmcs[ri].pp_pmc,
4418                             pm, pm->pm_state);
4419
4420                         KASSERT(PMC_TO_ROWINDEX(pm) == ri,
4421                             ("[pmc,%d] ri mismatch pmc(%d) ri(%d)",
4422                                 __LINE__, PMC_TO_ROWINDEX(pm), ri));
4423
4424                         KASSERT(pm == pp->pp_pmcs[ri].pp_pmc,
4425                             ("[pmc,%d] pm %p != pp_pmcs[%d] %p",
4426                                 __LINE__, pm, ri, pp->pp_pmcs[ri].pp_pmc));
4427
4428                         (void) pcd->pcd_stop_pmc(cpu, adjri);
4429
4430                         KASSERT(pm->pm_runcount > 0,
4431                             ("[pmc,%d] bad runcount ri %d rc %d",
4432                                 __LINE__, ri, pm->pm_runcount));
4433
4434                         /* Stop hardware only if it is actually running */
4435                         if (pm->pm_state == PMC_STATE_RUNNING &&
4436                             pm->pm_stalled == 0) {
4437                                 pcd->pcd_read_pmc(cpu, adjri, &newvalue);
4438                                 tmp = newvalue -
4439                                     PMC_PCPU_SAVED(cpu,ri);
4440
4441                                 mtx_pool_lock_spin(pmc_mtxpool, pm);
4442                                 pm->pm_gv.pm_savedvalue += tmp;
4443                                 pp->pp_pmcs[ri].pp_pmcval += tmp;
4444                                 mtx_pool_unlock_spin(pmc_mtxpool, pm);
4445                         }
4446
4447                         atomic_subtract_rel_int(&pm->pm_runcount,1);
4448
4449                         KASSERT((int) pm->pm_runcount >= 0,
4450                             ("[pmc,%d] runcount is %d", __LINE__, ri));
4451
4452                         (void) pcd->pcd_config_pmc(cpu, adjri, NULL);
4453                 }
4454
4455                 /*
4456                  * Inform the MD layer of this pseudo "context switch
4457                  * out"
4458                  */
4459                 (void) md->pmd_switch_out(pmc_pcpu[cpu], pp);
4460
4461                 critical_exit(); /* ok to be pre-empted now */
4462
4463                 /*
4464                  * Unlink this process from the PMCs that are
4465                  * targetting it.  This will send a signal to
4466                  * all PMC owner's whose PMCs are orphaned.
4467                  *
4468                  * Log PMC value at exit time if requested.
4469                  */
4470                 for (ri = 0; ri < md->pmd_npmc; ri++)
4471                         if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL) {
4472                                 if (pm->pm_flags & PMC_F_NEEDS_LOGFILE &&
4473                                     PMC_IS_COUNTING_MODE(PMC_TO_MODE(pm)))
4474                                         pmclog_process_procexit(pm, pp);
4475                                 pmc_unlink_target_process(pm, pp);
4476                         }
4477                 free(pp, M_PMC);
4478
4479         } else
4480                 critical_exit(); /* pp == NULL */
4481
4482
4483         /*
4484          * If the process owned PMCs, free them up and free up
4485          * memory.
4486          */
4487         if ((po = pmc_find_owner_descriptor(p)) != NULL) {
4488                 pmc_remove_owner(po);
4489                 pmc_destroy_owner_descriptor(po);
4490         }
4491
4492         sx_xunlock(&pmc_sx);
4493 }
4494
4495 /*
4496  * Handle a process fork.
4497  *
4498  * If the parent process 'p1' is under HWPMC monitoring, then copy
4499  * over any attached PMCs that have 'do_descendants' semantics.
4500  */
4501
4502 static void
4503 pmc_process_fork(void *arg __unused, struct proc *p1, struct proc *newproc,
4504     int flags)
4505 {
4506         int is_using_hwpmcs;
4507         unsigned int ri;
4508         uint32_t do_descendants;
4509         struct pmc *pm;
4510         struct pmc_owner *po;
4511         struct pmc_process *ppnew, *ppold;
4512
4513         (void) flags;           /* unused parameter */
4514
4515         PROC_LOCK(p1);
4516         is_using_hwpmcs = p1->p_flag & P_HWPMC;
4517         PROC_UNLOCK(p1);
4518
4519         /*
4520          * If there are system-wide sampling PMCs active, we need to
4521          * log all fork events to their owner's logs.
4522          */
4523
4524         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
4525             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
4526                     pmclog_process_procfork(po, p1->p_pid, newproc->p_pid);
4527
4528         if (!is_using_hwpmcs)
4529                 return;
4530
4531         PMC_GET_SX_XLOCK();
4532         PMCDBG(PMC,FRK,1, "process-fork proc=%p (%d, %s) -> %p", p1,
4533             p1->p_pid, p1->p_comm, newproc);
4534
4535         /*
4536          * If the parent process (curthread->td_proc) is a
4537          * target of any PMCs, look for PMCs that are to be
4538          * inherited, and link these into the new process
4539          * descriptor.
4540          */
4541         if ((ppold = pmc_find_process_descriptor(curthread->td_proc,
4542                  PMC_FLAG_NONE)) == NULL)
4543                 goto done;              /* nothing to do */
4544
4545         do_descendants = 0;
4546         for (ri = 0; ri < md->pmd_npmc; ri++)
4547                 if ((pm = ppold->pp_pmcs[ri].pp_pmc) != NULL)
4548                         do_descendants |= pm->pm_flags & PMC_F_DESCENDANTS;
4549         if (do_descendants == 0) /* nothing to do */
4550                 goto done;
4551
4552         /* allocate a descriptor for the new process  */
4553         if ((ppnew = pmc_find_process_descriptor(newproc,
4554                  PMC_FLAG_ALLOCATE)) == NULL)
4555                 goto done;
4556
4557         /*
4558          * Run through all PMCs that were targeting the old process
4559          * and which specified F_DESCENDANTS and attach them to the
4560          * new process.
4561          *
4562          * Log the fork event to all owners of PMCs attached to this
4563          * process, if not already logged.
4564          */
4565         for (ri = 0; ri < md->pmd_npmc; ri++)
4566                 if ((pm = ppold->pp_pmcs[ri].pp_pmc) != NULL &&
4567                     (pm->pm_flags & PMC_F_DESCENDANTS)) {
4568                         pmc_link_target_process(pm, ppnew);
4569                         po = pm->pm_owner;
4570                         if (po->po_sscount == 0 &&
4571                             po->po_flags & PMC_PO_OWNS_LOGFILE)
4572                                 pmclog_process_procfork(po, p1->p_pid,
4573                                     newproc->p_pid);
4574                 }
4575
4576         /*
4577          * Now mark the new process as being tracked by this driver.
4578          */
4579         PROC_LOCK(newproc);
4580         newproc->p_flag |= P_HWPMC;
4581         PROC_UNLOCK(newproc);
4582
4583  done:
4584         sx_xunlock(&pmc_sx);
4585 }
4586
4587 static void
4588 pmc_kld_load(void *arg __unused, linker_file_t lf)
4589 {
4590         struct pmc_owner *po;
4591
4592         sx_slock(&pmc_sx);
4593
4594         /*
4595          * Notify owners of system sampling PMCs about KLD operations.
4596          */
4597         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
4598                 if (po->po_flags & PMC_PO_OWNS_LOGFILE)
4599                         pmclog_process_map_in(po, (pid_t) -1,
4600                             (uintfptr_t) lf->address, lf->filename);
4601
4602         /*
4603          * TODO: Notify owners of (all) process-sampling PMCs too.
4604          */
4605
4606         sx_sunlock(&pmc_sx);
4607 }
4608
4609 static void
4610 pmc_kld_unload(void *arg __unused, const char *filename __unused,
4611     caddr_t address, size_t size)
4612 {
4613         struct pmc_owner *po;
4614
4615         sx_slock(&pmc_sx);
4616
4617         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
4618                 if (po->po_flags & PMC_PO_OWNS_LOGFILE)
4619                         pmclog_process_map_out(po, (pid_t) -1,
4620                             (uintfptr_t) address, (uintfptr_t) address + size);
4621
4622         /*
4623          * TODO: Notify owners of process-sampling PMCs.
4624          */
4625
4626         sx_sunlock(&pmc_sx);
4627 }
4628
4629 /*
4630  * initialization
4631  */
4632
4633 static const char *pmc_name_of_pmcclass[] = {
4634 #undef  __PMC_CLASS
4635 #define __PMC_CLASS(N) #N ,
4636         __PMC_CLASSES()
4637 };
4638
4639 /*
4640  * Base class initializer: allocate structure and set default classes.
4641  */
4642 struct pmc_mdep *
4643 pmc_mdep_alloc(int nclasses)
4644 {
4645         struct pmc_mdep *md;
4646         int     n;
4647
4648         /* SOFT + md classes */
4649         n = 1 + nclasses;
4650         md = malloc(sizeof(struct pmc_mdep) + n *
4651             sizeof(struct pmc_classdep), M_PMC, M_WAITOK|M_ZERO);
4652         md->pmd_nclass = n;
4653
4654         /* Add base class. */
4655         pmc_soft_initialize(md);
4656         return md;
4657 }
4658
4659 void
4660 pmc_mdep_free(struct pmc_mdep *md)
4661 {
4662         pmc_soft_finalize(md);
4663         free(md, M_PMC);
4664 }
4665
4666 static int
4667 generic_switch_in(struct pmc_cpu *pc, struct pmc_process *pp)
4668 {
4669         (void) pc; (void) pp;
4670
4671         return (0);
4672 }
4673
4674 static int
4675 generic_switch_out(struct pmc_cpu *pc, struct pmc_process *pp)
4676 {
4677         (void) pc; (void) pp;
4678
4679         return (0);
4680 }
4681
4682 static struct pmc_mdep *
4683 pmc_generic_cpu_initialize(void)
4684 {
4685         struct pmc_mdep *md;
4686
4687         md = pmc_mdep_alloc(0);
4688
4689         md->pmd_cputype    = PMC_CPU_GENERIC;
4690
4691         md->pmd_pcpu_init  = NULL;
4692         md->pmd_pcpu_fini  = NULL;
4693         md->pmd_switch_in  = generic_switch_in;
4694         md->pmd_switch_out = generic_switch_out;
4695
4696         return (md);
4697 }
4698
4699 static void
4700 pmc_generic_cpu_finalize(struct pmc_mdep *md)
4701 {
4702         (void) md;
4703 }
4704
4705
4706 static int
4707 pmc_initialize(void)
4708 {
4709         int c, cpu, error, n, ri;
4710         unsigned int maxcpu;
4711         struct pmc_binding pb;
4712         struct pmc_sample *ps;
4713         struct pmc_classdep *pcd;
4714         struct pmc_samplebuffer *sb;
4715
4716         md = NULL;
4717         error = 0;
4718
4719 #ifdef  DEBUG
4720         /* parse debug flags first */
4721         if (TUNABLE_STR_FETCH(PMC_SYSCTL_NAME_PREFIX "debugflags",
4722                 pmc_debugstr, sizeof(pmc_debugstr)))
4723                 pmc_debugflags_parse(pmc_debugstr,
4724                     pmc_debugstr+strlen(pmc_debugstr));
4725 #endif
4726
4727         PMCDBG(MOD,INI,0, "PMC Initialize (version %x)", PMC_VERSION);
4728
4729         /* check kernel version */
4730         if (pmc_kernel_version != PMC_VERSION) {
4731                 if (pmc_kernel_version == 0)
4732                         printf("hwpmc: this kernel has not been compiled with "
4733                             "'options HWPMC_HOOKS'.\n");
4734                 else
4735                         printf("hwpmc: kernel version (0x%x) does not match "
4736                             "module version (0x%x).\n", pmc_kernel_version,
4737                             PMC_VERSION);
4738                 return EPROGMISMATCH;
4739         }
4740
4741         /*
4742          * check sysctl parameters
4743          */
4744
4745         if (pmc_hashsize <= 0) {
4746                 (void) printf("hwpmc: tunable \"hashsize\"=%d must be "
4747                     "greater than zero.\n", pmc_hashsize);
4748                 pmc_hashsize = PMC_HASH_SIZE;
4749         }
4750
4751         if (pmc_nsamples <= 0 || pmc_nsamples > 65535) {
4752                 (void) printf("hwpmc: tunable \"nsamples\"=%d out of "
4753                     "range.\n", pmc_nsamples);
4754                 pmc_nsamples = PMC_NSAMPLES;
4755         }
4756
4757         if (pmc_callchaindepth <= 0 ||
4758             pmc_callchaindepth > PMC_CALLCHAIN_DEPTH_MAX) {
4759                 (void) printf("hwpmc: tunable \"callchaindepth\"=%d out of "
4760                     "range.\n", pmc_callchaindepth);
4761                 pmc_callchaindepth = PMC_CALLCHAIN_DEPTH;
4762         }
4763
4764         md = pmc_md_initialize();
4765         if (md == NULL) {
4766                 /* Default to generic CPU. */
4767                 md = pmc_generic_cpu_initialize();
4768                 if (md == NULL)
4769                         return (ENOSYS);
4770         }
4771
4772         KASSERT(md->pmd_nclass >= 1 && md->pmd_npmc >= 1,
4773             ("[pmc,%d] no classes or pmcs", __LINE__));
4774
4775         /* Compute the map from row-indices to classdep pointers. */
4776         pmc_rowindex_to_classdep = malloc(sizeof(struct pmc_classdep *) *
4777             md->pmd_npmc, M_PMC, M_WAITOK|M_ZERO);
4778
4779         for (n = 0; n < md->pmd_npmc; n++)
4780                 pmc_rowindex_to_classdep[n] = NULL;
4781         for (ri = c = 0; c < md->pmd_nclass; c++) {
4782                 pcd = &md->pmd_classdep[c];
4783                 for (n = 0; n < pcd->pcd_num; n++, ri++)
4784                         pmc_rowindex_to_classdep[ri] = pcd;
4785         }
4786
4787         KASSERT(ri == md->pmd_npmc,
4788             ("[pmc,%d] npmc miscomputed: ri=%d, md->npmc=%d", __LINE__,
4789             ri, md->pmd_npmc));
4790
4791         maxcpu = pmc_cpu_max();
4792
4793         /* allocate space for the per-cpu array */
4794         pmc_pcpu = malloc(maxcpu * sizeof(struct pmc_cpu *), M_PMC,
4795             M_WAITOK|M_ZERO);
4796
4797         /* per-cpu 'saved values' for managing process-mode PMCs */
4798         pmc_pcpu_saved = malloc(sizeof(pmc_value_t) * maxcpu * md->pmd_npmc,
4799             M_PMC, M_WAITOK);
4800
4801         /* Perform CPU-dependent initialization. */
4802         pmc_save_cpu_binding(&pb);
4803         error = 0;
4804         for (cpu = 0; error == 0 && cpu < maxcpu; cpu++) {
4805                 if (!pmc_cpu_is_active(cpu))
4806                         continue;
4807                 pmc_select_cpu(cpu);
4808                 pmc_pcpu[cpu] = malloc(sizeof(struct pmc_cpu) +
4809                     md->pmd_npmc * sizeof(struct pmc_hw *), M_PMC,
4810                     M_WAITOK|M_ZERO);
4811                 if (md->pmd_pcpu_init)
4812                         error = md->pmd_pcpu_init(md, cpu);
4813                 for (n = 0; error == 0 && n < md->pmd_nclass; n++)
4814                         error = md->pmd_classdep[n].pcd_pcpu_init(md, cpu);
4815         }
4816         pmc_restore_cpu_binding(&pb);
4817
4818         if (error)
4819                 return (error);
4820
4821         /* allocate space for the sample array */
4822         for (cpu = 0; cpu < maxcpu; cpu++) {
4823                 if (!pmc_cpu_is_active(cpu))
4824                         continue;
4825
4826                 sb = malloc(sizeof(struct pmc_samplebuffer) +
4827                     pmc_nsamples * sizeof(struct pmc_sample), M_PMC,
4828                     M_WAITOK|M_ZERO);
4829                 sb->ps_read = sb->ps_write = sb->ps_samples;
4830                 sb->ps_fence = sb->ps_samples + pmc_nsamples;
4831
4832                 KASSERT(pmc_pcpu[cpu] != NULL,
4833                     ("[pmc,%d] cpu=%d Null per-cpu data", __LINE__, cpu));
4834
4835                 sb->ps_callchains = malloc(pmc_callchaindepth * pmc_nsamples *
4836                     sizeof(uintptr_t), M_PMC, M_WAITOK|M_ZERO);
4837
4838                 for (n = 0, ps = sb->ps_samples; n < pmc_nsamples; n++, ps++)
4839                         ps->ps_pc = sb->ps_callchains +
4840                             (n * pmc_callchaindepth);
4841
4842                 pmc_pcpu[cpu]->pc_sb[PMC_HR] = sb;
4843
4844                 sb = malloc(sizeof(struct pmc_samplebuffer) +
4845                     pmc_nsamples * sizeof(struct pmc_sample), M_PMC,
4846                     M_WAITOK|M_ZERO);
4847                 sb->ps_read = sb->ps_write = sb->ps_samples;
4848                 sb->ps_fence = sb->ps_samples + pmc_nsamples;
4849
4850                 KASSERT(pmc_pcpu[cpu] != NULL,
4851                     ("[pmc,%d] cpu=%d Null per-cpu data", __LINE__, cpu));
4852
4853                 sb->ps_callchains = malloc(pmc_callchaindepth * pmc_nsamples *
4854                     sizeof(uintptr_t), M_PMC, M_WAITOK|M_ZERO);
4855
4856                 for (n = 0, ps = sb->ps_samples; n < pmc_nsamples; n++, ps++)
4857                         ps->ps_pc = sb->ps_callchains +
4858                             (n * pmc_callchaindepth);
4859
4860                 pmc_pcpu[cpu]->pc_sb[PMC_SR] = sb;
4861         }
4862
4863         /* allocate space for the row disposition array */
4864         pmc_pmcdisp = malloc(sizeof(enum pmc_mode) * md->pmd_npmc,
4865             M_PMC, M_WAITOK|M_ZERO);
4866
4867         /* mark all PMCs as available */
4868         for (n = 0; n < (int) md->pmd_npmc; n++)
4869                 PMC_MARK_ROW_FREE(n);
4870
4871         /* allocate thread hash tables */
4872         pmc_ownerhash = hashinit(pmc_hashsize, M_PMC,
4873             &pmc_ownerhashmask);
4874
4875         pmc_processhash = hashinit(pmc_hashsize, M_PMC,
4876             &pmc_processhashmask);
4877         mtx_init(&pmc_processhash_mtx, "pmc-process-hash", "pmc-leaf",
4878             MTX_SPIN);
4879
4880         LIST_INIT(&pmc_ss_owners);
4881         pmc_ss_count = 0;
4882
4883         /* allocate a pool of spin mutexes */
4884         pmc_mtxpool = mtx_pool_create("pmc-leaf", pmc_mtxpool_size,
4885             MTX_SPIN);
4886
4887         PMCDBG(MOD,INI,1, "pmc_ownerhash=%p, mask=0x%lx "
4888             "targethash=%p mask=0x%lx", pmc_ownerhash, pmc_ownerhashmask,
4889             pmc_processhash, pmc_processhashmask);
4890
4891         /* register process {exit,fork,exec} handlers */
4892         pmc_exit_tag = EVENTHANDLER_REGISTER(process_exit,
4893             pmc_process_exit, NULL, EVENTHANDLER_PRI_ANY);
4894         pmc_fork_tag = EVENTHANDLER_REGISTER(process_fork,
4895             pmc_process_fork, NULL, EVENTHANDLER_PRI_ANY);
4896
4897         /* register kld event handlers */
4898         pmc_kld_load_tag = EVENTHANDLER_REGISTER(kld_load, pmc_kld_load,
4899             NULL, EVENTHANDLER_PRI_ANY);
4900         pmc_kld_unload_tag = EVENTHANDLER_REGISTER(kld_unload, pmc_kld_unload,
4901             NULL, EVENTHANDLER_PRI_ANY);
4902
4903         /* initialize logging */
4904         pmclog_initialize();
4905
4906         /* set hook functions */
4907         pmc_intr = md->pmd_intr;
4908         pmc_hook = pmc_hook_handler;
4909
4910         if (error == 0) {
4911                 printf(PMC_MODULE_NAME ":");
4912                 for (n = 0; n < (int) md->pmd_nclass; n++) {
4913                         pcd = &md->pmd_classdep[n];
4914                         printf(" %s/%d/%d/0x%b",
4915                             pmc_name_of_pmcclass[pcd->pcd_class],
4916                             pcd->pcd_num,
4917                             pcd->pcd_width,
4918                             pcd->pcd_caps,
4919                             "\20"
4920                             "\1INT\2USR\3SYS\4EDG\5THR"
4921                             "\6REA\7WRI\10INV\11QUA\12PRC"
4922                             "\13TAG\14CSC");
4923                 }
4924                 printf("\n");
4925         }
4926
4927         return (error);
4928 }
4929
4930 /* prepare to be unloaded */
4931 static void
4932 pmc_cleanup(void)
4933 {
4934         int c, cpu;
4935         unsigned int maxcpu;
4936         struct pmc_ownerhash *ph;
4937         struct pmc_owner *po, *tmp;
4938         struct pmc_binding pb;
4939 #ifdef  DEBUG
4940         struct pmc_processhash *prh;
4941 #endif
4942
4943         PMCDBG(MOD,INI,0, "%s", "cleanup");
4944
4945         /* switch off sampling */
4946         CPU_ZERO(&pmc_cpumask);
4947         pmc_intr = NULL;
4948
4949         sx_xlock(&pmc_sx);
4950         if (pmc_hook == NULL) { /* being unloaded already */
4951                 sx_xunlock(&pmc_sx);
4952                 return;
4953         }
4954
4955         pmc_hook = NULL; /* prevent new threads from entering module */
4956
4957         /* deregister event handlers */
4958         EVENTHANDLER_DEREGISTER(process_fork, pmc_fork_tag);
4959         EVENTHANDLER_DEREGISTER(process_exit, pmc_exit_tag);
4960         EVENTHANDLER_DEREGISTER(kld_load, pmc_kld_load_tag);
4961         EVENTHANDLER_DEREGISTER(kld_unload, pmc_kld_unload_tag);
4962
4963         /* send SIGBUS to all owner threads, free up allocations */
4964         if (pmc_ownerhash)
4965                 for (ph = pmc_ownerhash;
4966                      ph <= &pmc_ownerhash[pmc_ownerhashmask];
4967                      ph++) {
4968                         LIST_FOREACH_SAFE(po, ph, po_next, tmp) {
4969                                 pmc_remove_owner(po);
4970
4971                                 /* send SIGBUS to owner processes */
4972                                 PMCDBG(MOD,INI,2, "cleanup signal proc=%p "
4973                                     "(%d, %s)", po->po_owner,
4974                                     po->po_owner->p_pid,
4975                                     po->po_owner->p_comm);
4976
4977                                 PROC_LOCK(po->po_owner);
4978                                 kern_psignal(po->po_owner, SIGBUS);
4979                                 PROC_UNLOCK(po->po_owner);
4980
4981                                 pmc_destroy_owner_descriptor(po);
4982                         }
4983                 }
4984
4985         /* reclaim allocated data structures */
4986         if (pmc_mtxpool)
4987                 mtx_pool_destroy(&pmc_mtxpool);
4988
4989         mtx_destroy(&pmc_processhash_mtx);
4990         if (pmc_processhash) {
4991 #ifdef  DEBUG
4992                 struct pmc_process *pp;
4993
4994                 PMCDBG(MOD,INI,3, "%s", "destroy process hash");
4995                 for (prh = pmc_processhash;
4996                      prh <= &pmc_processhash[pmc_processhashmask];
4997                      prh++)
4998                         LIST_FOREACH(pp, prh, pp_next)
4999                             PMCDBG(MOD,INI,3, "pid=%d", pp->pp_proc->p_pid);
5000 #endif
5001
5002                 hashdestroy(pmc_processhash, M_PMC, pmc_processhashmask);
5003                 pmc_processhash = NULL;
5004         }
5005
5006         if (pmc_ownerhash) {
5007                 PMCDBG(MOD,INI,3, "%s", "destroy owner hash");
5008                 hashdestroy(pmc_ownerhash, M_PMC, pmc_ownerhashmask);
5009                 pmc_ownerhash = NULL;
5010         }
5011
5012         KASSERT(LIST_EMPTY(&pmc_ss_owners),
5013             ("[pmc,%d] Global SS owner list not empty", __LINE__));
5014         KASSERT(pmc_ss_count == 0,
5015             ("[pmc,%d] Global SS count not empty", __LINE__));
5016
5017         /* do processor and pmc-class dependent cleanup */
5018         maxcpu = pmc_cpu_max();
5019
5020         PMCDBG(MOD,INI,3, "%s", "md cleanup");
5021         if (md) {
5022                 pmc_save_cpu_binding(&pb);
5023                 for (cpu = 0; cpu < maxcpu; cpu++) {
5024                         PMCDBG(MOD,INI,1,"pmc-cleanup cpu=%d pcs=%p",
5025                             cpu, pmc_pcpu[cpu]);
5026                         if (!pmc_cpu_is_active(cpu) || pmc_pcpu[cpu] == NULL)
5027                                 continue;
5028                         pmc_select_cpu(cpu);
5029                         for (c = 0; c < md->pmd_nclass; c++)
5030                                 md->pmd_classdep[c].pcd_pcpu_fini(md, cpu);
5031                         if (md->pmd_pcpu_fini)
5032                                 md->pmd_pcpu_fini(md, cpu);
5033                 }
5034
5035                 if (md->pmd_cputype == PMC_CPU_GENERIC)
5036                         pmc_generic_cpu_finalize(md);
5037                 else
5038                         pmc_md_finalize(md);
5039
5040                 pmc_mdep_free(md);
5041                 md = NULL;
5042                 pmc_restore_cpu_binding(&pb);
5043         }
5044
5045         /* Free per-cpu descriptors. */
5046         for (cpu = 0; cpu < maxcpu; cpu++) {
5047                 if (!pmc_cpu_is_active(cpu))
5048                         continue;
5049                 KASSERT(pmc_pcpu[cpu]->pc_sb[PMC_HR] != NULL,
5050                     ("[pmc,%d] Null hw cpu sample buffer cpu=%d", __LINE__,
5051                         cpu));
5052                 KASSERT(pmc_pcpu[cpu]->pc_sb[PMC_SR] != NULL,
5053                     ("[pmc,%d] Null sw cpu sample buffer cpu=%d", __LINE__,
5054                         cpu));
5055                 free(pmc_pcpu[cpu]->pc_sb[PMC_HR]->ps_callchains, M_PMC);
5056                 free(pmc_pcpu[cpu]->pc_sb[PMC_HR], M_PMC);
5057                 free(pmc_pcpu[cpu]->pc_sb[PMC_SR]->ps_callchains, M_PMC);
5058                 free(pmc_pcpu[cpu]->pc_sb[PMC_SR], M_PMC);
5059                 free(pmc_pcpu[cpu], M_PMC);
5060         }
5061
5062         free(pmc_pcpu, M_PMC);
5063         pmc_pcpu = NULL;
5064
5065         free(pmc_pcpu_saved, M_PMC);
5066         pmc_pcpu_saved = NULL;
5067
5068         if (pmc_pmcdisp) {
5069                 free(pmc_pmcdisp, M_PMC);
5070                 pmc_pmcdisp = NULL;
5071         }
5072
5073         if (pmc_rowindex_to_classdep) {
5074                 free(pmc_rowindex_to_classdep, M_PMC);
5075                 pmc_rowindex_to_classdep = NULL;
5076         }
5077
5078         pmclog_shutdown();
5079
5080         sx_xunlock(&pmc_sx);    /* we are done */
5081 }
5082
5083 /*
5084  * The function called at load/unload.
5085  */
5086
5087 static int
5088 load (struct module *module __unused, int cmd, void *arg __unused)
5089 {
5090         int error;
5091
5092         error = 0;
5093
5094         switch (cmd) {
5095         case MOD_LOAD :
5096                 /* initialize the subsystem */
5097                 error = pmc_initialize();
5098                 if (error != 0)
5099                         break;
5100                 PMCDBG(MOD,INI,1, "syscall=%d maxcpu=%d",
5101                     pmc_syscall_num, pmc_cpu_max());
5102                 break;
5103
5104
5105         case MOD_UNLOAD :
5106         case MOD_SHUTDOWN:
5107                 pmc_cleanup();
5108                 PMCDBG(MOD,INI,1, "%s", "unloaded");
5109                 break;
5110
5111         default :
5112                 error = EINVAL; /* XXX should panic(9) */
5113                 break;
5114         }
5115
5116         return error;
5117 }
5118
5119 /* memory pool */
5120 MALLOC_DEFINE(M_PMC, "pmc", "Memory space for the PMC module");