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/mutex.h>
  45 #include <sys/pmc.h>
  46 #include <sys/pmckern.h>
  47 #include <sys/pmclog.h>
  48 #include <sys/priv.h>
  49 #include <sys/proc.h>
  50 #include <sys/queue.h>
  51 #include <sys/resourcevar.h>
  52 #include <sys/sched.h>
  53 #include <sys/signalvar.h>
  54 #include <sys/smp.h>
  55 #include <sys/sx.h>
  56 #include <sys/sysctl.h>
  57 #include <sys/sysent.h>
  58 #include <sys/systm.h>
  59 #include <sys/vnode.h>
  60
  61 #include <sys/linker.h>         /* needs to be after <sys/malloc.h> */
  62
  63 #include <machine/atomic.h>
  64 #include <machine/md_var.h>
  65
  66 /*
  67  * Types
  68  */
  69
  70 enum pmc_flags {
  71         PMC_FLAG_NONE     = 0x00, /* do nothing */
  72         PMC_FLAG_REMOVE   = 0x01, /* atomically remove entry from hash */
  73         PMC_FLAG_ALLOCATE = 0x02, /* add entry to hash if not found */
  74 };
  75
  76 /*
  77  * The offset in sysent where the syscall is allocated.
  78  */
  79
  80 static int pmc_syscall_num = NO_SYSCALL;
  81 struct pmc_cpu          **pmc_pcpu;      /* per-cpu state */
  82 pmc_value_t             *pmc_pcpu_saved; /* saved PMC values: CSW handling */
  83
  84 #define PMC_PCPU_SAVED(C,R)     pmc_pcpu_saved[(R) + md->pmd_npmc*(C)]
  85
  86 struct mtx_pool         *pmc_mtxpool;
  87 static int              *pmc_pmcdisp;    /* PMC row dispositions */
  88
  89 #define PMC_ROW_DISP_IS_FREE(R)         (pmc_pmcdisp[(R)] == 0)
  90 #define PMC_ROW_DISP_IS_THREAD(R)       (pmc_pmcdisp[(R)] > 0)
  91 #define PMC_ROW_DISP_IS_STANDALONE(R)   (pmc_pmcdisp[(R)] < 0)
  92
  93 #define PMC_MARK_ROW_FREE(R) do {                                         \
  94         pmc_pmcdisp[(R)] = 0;                                             \
  95 } while (0)
  96
  97 #define PMC_MARK_ROW_STANDALONE(R) do {                                   \
  98         KASSERT(pmc_pmcdisp[(R)] <= 0, ("[pmc,%d] row disposition error", \
  99                     __LINE__));                                           \
 100         atomic_add_int(&pmc_pmcdisp[(R)], -1);                            \
 101         KASSERT(pmc_pmcdisp[(R)] >= (-pmc_cpu_max_active()),              \
 102                 ("[pmc,%d] row disposition error", __LINE__));            \
 103 } while (0)
 104
 105 #define PMC_UNMARK_ROW_STANDALONE(R) do {                                 \
 106         atomic_add_int(&pmc_pmcdisp[(R)], 1);                             \
 107         KASSERT(pmc_pmcdisp[(R)] <= 0, ("[pmc,%d] row disposition error", \
 108                     __LINE__));                                           \
 109 } while (0)
 110
 111 #define PMC_MARK_ROW_THREAD(R) do {                                       \
 112         KASSERT(pmc_pmcdisp[(R)] >= 0, ("[pmc,%d] row disposition error", \
 113                     __LINE__));                                           \
 114         atomic_add_int(&pmc_pmcdisp[(R)], 1);                             \
 115 } while (0)
 116
 117 #define PMC_UNMARK_ROW_THREAD(R) do {                                     \
 118         atomic_add_int(&pmc_pmcdisp[(R)], -1);                            \
 119         KASSERT(pmc_pmcdisp[(R)] >= 0, ("[pmc,%d] row disposition error", \
 120                     __LINE__));                                           \
 121 } while (0)
 122
 123
 124 /* various event handlers */
 125 static eventhandler_tag pmc_exit_tag, pmc_fork_tag;
 126
 127 /* Module statistics */
 128 struct pmc_op_getdriverstats pmc_stats;
 129
 130 /* Machine/processor dependent operations */
 131 static struct pmc_mdep  *md;
 132
 133 /*
 134  * Hash tables mapping owner processes and target threads to PMCs.
 135  */
 136
 137 struct mtx pmc_processhash_mtx;         /* spin mutex */
 138 static u_long pmc_processhashmask;
 139 static LIST_HEAD(pmc_processhash, pmc_process)  *pmc_processhash;
 140
 141 /*
 142  * Hash table of PMC owner descriptors.  This table is protected by
 143  * the shared PMC "sx" lock.
 144  */
 145
 146 static u_long pmc_ownerhashmask;
 147 static LIST_HEAD(pmc_ownerhash, pmc_owner)      *pmc_ownerhash;
 148
 149 /*
 150  * List of PMC owners with system-wide sampling PMCs.
 151  */
 152
 153 static LIST_HEAD(, pmc_owner)                   pmc_ss_owners;
 154
 155
 156 /*
 157  * A map of row indices to classdep structures.
 158  */
 159 static struct pmc_classdep **pmc_rowindex_to_classdep;
 160
 161 /*
 162  * Prototypes
 163  */
 164
 165 #ifdef  DEBUG
 166 static int      pmc_debugflags_sysctl_handler(SYSCTL_HANDLER_ARGS);
 167 static int      pmc_debugflags_parse(char *newstr, char *fence);
 168 #endif
 169
 170 static int      load(struct module *module, int cmd, void *arg);
 171 static int      pmc_attach_process(struct proc *p, struct pmc *pm);
 172 static struct pmc *pmc_allocate_pmc_descriptor(void);
 173 static struct pmc_owner *pmc_allocate_owner_descriptor(struct proc *p);
 174 static int      pmc_attach_one_process(struct proc *p, struct pmc *pm);
 175 static int      pmc_can_allocate_rowindex(struct proc *p, unsigned int ri,
 176     int cpu);
 177 static int      pmc_can_attach(struct pmc *pm, struct proc *p);
 178 static void     pmc_capture_user_callchain(int cpu, struct trapframe *tf);
 179 static void     pmc_cleanup(void);
 180 static int      pmc_detach_process(struct proc *p, struct pmc *pm);
 181 static int      pmc_detach_one_process(struct proc *p, struct pmc *pm,
 182     int flags);
 183 static void     pmc_destroy_owner_descriptor(struct pmc_owner *po);
 184 static struct pmc_owner *pmc_find_owner_descriptor(struct proc *p);
 185 static int      pmc_find_pmc(pmc_id_t pmcid, struct pmc **pm);
 186 static struct pmc *pmc_find_pmc_descriptor_in_process(struct pmc_owner *po,
 187     pmc_id_t pmc);
 188 static struct pmc_process *pmc_find_process_descriptor(struct proc *p,
 189     uint32_t mode);
 190 static void     pmc_force_context_switch(void);
 191 static void     pmc_link_target_process(struct pmc *pm,
 192     struct pmc_process *pp);
 193 static void     pmc_log_all_process_mappings(struct pmc_owner *po);
 194 static void     pmc_log_kernel_mappings(struct pmc *pm);
 195 static void     pmc_log_process_mappings(struct pmc_owner *po, struct proc *p);
 196 static void     pmc_maybe_remove_owner(struct pmc_owner *po);
 197 static void     pmc_process_csw_in(struct thread *td);
 198 static void     pmc_process_csw_out(struct thread *td);
 199 static void     pmc_process_exit(void *arg, struct proc *p);
 200 static void     pmc_process_fork(void *arg, struct proc *p1,
 201     struct proc *p2, int n);
 202 static void     pmc_process_samples(int cpu);
 203 static void     pmc_release_pmc_descriptor(struct pmc *pmc);
 204 static void     pmc_remove_owner(struct pmc_owner *po);
 205 static void     pmc_remove_process_descriptor(struct pmc_process *pp);
 206 static void     pmc_restore_cpu_binding(struct pmc_binding *pb);
 207 static void     pmc_save_cpu_binding(struct pmc_binding *pb);
 208 static void     pmc_select_cpu(int cpu);
 209 static int      pmc_start(struct pmc *pm);
 210 static int      pmc_stop(struct pmc *pm);
 211 static int      pmc_syscall_handler(struct thread *td, void *syscall_args);
 212 static void     pmc_unlink_target_process(struct pmc *pmc,
 213     struct pmc_process *pp);
 214
 215 /*
 216  * Kernel tunables and sysctl(8) interface.
 217  */
 218
 219 SYSCTL_NODE(_kern, OID_AUTO, hwpmc, CTLFLAG_RW, 0, "HWPMC parameters");
 220
 221 static int pmc_callchaindepth = PMC_CALLCHAIN_DEPTH;
 222 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "callchaindepth", &pmc_callchaindepth);
 223 SYSCTL_INT(_kern_hwpmc, OID_AUTO, callchaindepth, CTLFLAG_TUN|CTLFLAG_RD,
 224     &pmc_callchaindepth, 0, "depth of call chain records");
 225
 226 #ifdef  DEBUG
 227 struct pmc_debugflags pmc_debugflags = PMC_DEBUG_DEFAULT_FLAGS;
 228 char    pmc_debugstr[PMC_DEBUG_STRSIZE];
 229 TUNABLE_STR(PMC_SYSCTL_NAME_PREFIX "debugflags", pmc_debugstr,
 230     sizeof(pmc_debugstr));
 231 SYSCTL_PROC(_kern_hwpmc, OID_AUTO, debugflags,
 232     CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_TUN,
 233     0, 0, pmc_debugflags_sysctl_handler, "A", "debug flags");
 234 #endif
 235
 236 /*
 237  * kern.hwpmc.hashrows -- determines the number of rows in the
 238  * of the hash table used to look up threads
 239  */
 240
 241 static int pmc_hashsize = PMC_HASH_SIZE;
 242 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "hashsize", &pmc_hashsize);
 243 SYSCTL_INT(_kern_hwpmc, OID_AUTO, hashsize, CTLFLAG_TUN|CTLFLAG_RD,
 244     &pmc_hashsize, 0, "rows in hash tables");
 245
 246 /*
 247  * kern.hwpmc.nsamples --- number of PC samples/callchain stacks per CPU
 248  */
 249
 250 static int pmc_nsamples = PMC_NSAMPLES;
 251 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "nsamples", &pmc_nsamples);
 252 SYSCTL_INT(_kern_hwpmc, OID_AUTO, nsamples, CTLFLAG_TUN|CTLFLAG_RD,
 253     &pmc_nsamples, 0, "number of PC samples per CPU");
 254
 255
 256 /*
 257  * kern.hwpmc.mtxpoolsize -- number of mutexes in the mutex pool.
 258  */
 259
 260 static int pmc_mtxpool_size = PMC_MTXPOOL_SIZE;
 261 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "mtxpoolsize", &pmc_mtxpool_size);
 262 SYSCTL_INT(_kern_hwpmc, OID_AUTO, mtxpoolsize, CTLFLAG_TUN|CTLFLAG_RD,
 263     &pmc_mtxpool_size, 0, "size of spin mutex pool");
 264
 265
 266 /*
 267  * security.bsd.unprivileged_syspmcs -- allow non-root processes to
 268  * allocate system-wide PMCs.
 269  *
 270  * Allowing unprivileged processes to allocate system PMCs is convenient
 271  * if system-wide measurements need to be taken concurrently with other
 272  * per-process measurements.  This feature is turned off by default.
 273  */
 274
 275 static int pmc_unprivileged_syspmcs = 0;
 276 TUNABLE_INT("security.bsd.unprivileged_syspmcs", &pmc_unprivileged_syspmcs);
 277 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_syspmcs, CTLFLAG_RW,
 278     &pmc_unprivileged_syspmcs, 0,
 279     "allow unprivileged process to allocate system PMCs");
 280
 281 /*
 282  * Hash function.  Discard the lower 2 bits of the pointer since
 283  * these are always zero for our uses.  The hash multiplier is
 284  * round((2^LONG_BIT) * ((sqrt(5)-1)/2)).
 285  */
 286
 287 #if     LONG_BIT == 64
 288 #define _PMC_HM         11400714819323198486u
 289 #elif   LONG_BIT == 32
 290 #define _PMC_HM         2654435769u
 291 #else
 292 #error  Must know the size of 'long' to compile
 293 #endif
 294
 295 #define PMC_HASH_PTR(P,M)       ((((unsigned long) (P) >> 2) * _PMC_HM) & (M))
 296
 297 /*
 298  * Syscall structures
 299  */
 300
 301 /* The `sysent' for the new syscall */
 302 static struct sysent pmc_sysent = {
 303         2,                      /* sy_narg */
 304         pmc_syscall_handler     /* sy_call */
 305 };
 306
 307 static struct syscall_module_data pmc_syscall_mod = {
 308         load,
 309         NULL,
 310         &pmc_syscall_num,
 311         &pmc_sysent,
 312         { 0, NULL }
 313 };
 314
 315 static moduledata_t pmc_mod = {
 316         PMC_MODULE_NAME,
 317         syscall_module_handler,
 318         &pmc_syscall_mod
 319 };
 320
 321 DECLARE_MODULE(pmc, pmc_mod, SI_SUB_SMP, SI_ORDER_ANY);
 322 MODULE_VERSION(pmc, PMC_VERSION);
 323
 324 #ifdef  DEBUG
 325 enum pmc_dbgparse_state {
 326         PMCDS_WS,               /* in whitespace */
 327         PMCDS_MAJOR,            /* seen a major keyword */
 328         PMCDS_MINOR
 329 };
 330
 331 static int
 332 pmc_debugflags_parse(char *newstr, char *fence)
 333 {
 334         char c, *p, *q;
 335         struct pmc_debugflags *tmpflags;
 336         int error, found, *newbits, tmp;
 337         size_t kwlen;
 338
 339         tmpflags = malloc(sizeof(*tmpflags), M_PMC, M_WAITOK|M_ZERO);
 340
 341         p = newstr;
 342         error = 0;
 343
 344         for (; p < fence && (c = *p); p++) {
 345
 346                 /* skip white space */
 347                 if (c == ' ' || c == '\t')
 348                         continue;
 349
 350                 /* look for a keyword followed by "=" */
 351                 for (q = p; p < fence && (c = *p) && c != '='; p++)
 352                         ;
 353                 if (c != '=') {
 354                         error = EINVAL;
 355                         goto done;
 356                 }
 357
 358                 kwlen = p - q;
 359                 newbits = NULL;
 360
 361                 /* lookup flag group name */
 362 #define DBG_SET_FLAG_MAJ(S,F)                                           \
 363                 if (kwlen == sizeof(S)-1 && strncmp(q, S, kwlen) == 0)  \
 364                         newbits = &tmpflags->pdb_ ## F;
 365
 366                 DBG_SET_FLAG_MAJ("cpu",         CPU);
 367                 DBG_SET_FLAG_MAJ("csw",         CSW);
 368                 DBG_SET_FLAG_MAJ("logging",     LOG);
 369                 DBG_SET_FLAG_MAJ("module",      MOD);
 370                 DBG_SET_FLAG_MAJ("md",          MDP);
 371                 DBG_SET_FLAG_MAJ("owner",       OWN);
 372                 DBG_SET_FLAG_MAJ("pmc",         PMC);
 373                 DBG_SET_FLAG_MAJ("process",     PRC);
 374                 DBG_SET_FLAG_MAJ("sampling",    SAM);
 375
 376                 if (newbits == NULL) {
 377                         error = EINVAL;
 378                         goto done;
 379                 }
 380
 381                 p++;            /* skip the '=' */
 382
 383                 /* Now parse the individual flags */
 384                 tmp = 0;
 385         newflag:
 386                 for (q = p; p < fence && (c = *p); p++)
 387                         if (c == ' ' || c == '\t' || c == ',')
 388                                 break;
 389
 390                 /* p == fence or c == ws or c == "," or c == 0 */
 391
 392                 if ((kwlen = p - q) == 0) {
 393                         *newbits = tmp;
 394                         continue;
 395                 }
 396
 397                 found = 0;
 398 #define DBG_SET_FLAG_MIN(S,F)                                           \
 399                 if (kwlen == sizeof(S)-1 && strncmp(q, S, kwlen) == 0)  \
 400                         tmp |= found = (1 << PMC_DEBUG_MIN_ ## F)
 401
 402                 /* a '*' denotes all possible flags in the group */
 403                 if (kwlen == 1 && *q == '*')
 404                         tmp = found = ~0;
 405                 /* look for individual flag names */
 406                 DBG_SET_FLAG_MIN("allocaterow", ALR);
 407                 DBG_SET_FLAG_MIN("allocate",    ALL);
 408                 DBG_SET_FLAG_MIN("attach",      ATT);
 409                 DBG_SET_FLAG_MIN("bind",        BND);
 410                 DBG_SET_FLAG_MIN("config",      CFG);
 411                 DBG_SET_FLAG_MIN("exec",        EXC);
 412                 DBG_SET_FLAG_MIN("exit",        EXT);
 413                 DBG_SET_FLAG_MIN("find",        FND);
 414                 DBG_SET_FLAG_MIN("flush",       FLS);
 415                 DBG_SET_FLAG_MIN("fork",        FRK);
 416                 DBG_SET_FLAG_MIN("getbuf",      GTB);
 417                 DBG_SET_FLAG_MIN("hook",        PMH);
 418                 DBG_SET_FLAG_MIN("init",        INI);
 419                 DBG_SET_FLAG_MIN("intr",        INT);
 420                 DBG_SET_FLAG_MIN("linktarget",  TLK);
 421                 DBG_SET_FLAG_MIN("mayberemove", OMR);
 422                 DBG_SET_FLAG_MIN("ops",         OPS);
 423                 DBG_SET_FLAG_MIN("read",        REA);
 424                 DBG_SET_FLAG_MIN("register",    REG);
 425                 DBG_SET_FLAG_MIN("release",     REL);
 426                 DBG_SET_FLAG_MIN("remove",      ORM);
 427                 DBG_SET_FLAG_MIN("sample",      SAM);
 428                 DBG_SET_FLAG_MIN("scheduleio",  SIO);
 429                 DBG_SET_FLAG_MIN("select",      SEL);
 430                 DBG_SET_FLAG_MIN("signal",      SIG);
 431                 DBG_SET_FLAG_MIN("swi",         SWI);
 432                 DBG_SET_FLAG_MIN("swo",         SWO);
 433                 DBG_SET_FLAG_MIN("start",       STA);
 434                 DBG_SET_FLAG_MIN("stop",        STO);
 435                 DBG_SET_FLAG_MIN("syscall",     PMS);
 436                 DBG_SET_FLAG_MIN("unlinktarget", TUL);
 437                 DBG_SET_FLAG_MIN("write",       WRI);
 438                 if (found == 0) {
 439                         /* unrecognized flag name */
 440                         error = EINVAL;
 441                         goto done;
 442                 }
 443
 444                 if (c == 0 || c == ' ' || c == '\t') {  /* end of flag group */
 445                         *newbits = tmp;
 446                         continue;
 447                 }
 448
 449                 p++;
 450                 goto newflag;
 451         }
 452
 453         /* save the new flag set */
 454         bcopy(tmpflags, &pmc_debugflags, sizeof(pmc_debugflags));
 455
 456  done:
 457         free(tmpflags, M_PMC);
 458         return error;
 459 }
 460
 461 static int
 462 pmc_debugflags_sysctl_handler(SYSCTL_HANDLER_ARGS)
 463 {
 464         char *fence, *newstr;
 465         int error;
 466         unsigned int n;
 467
 468         (void) arg1; (void) arg2; /* unused parameters */
 469
 470         n = sizeof(pmc_debugstr);
 471         newstr = malloc(n, M_PMC, M_WAITOK|M_ZERO);
 472         (void) strlcpy(newstr, pmc_debugstr, n);
 473
 474         error = sysctl_handle_string(oidp, newstr, n, req);
 475
 476         /* if there is a new string, parse and copy it */
 477         if (error == 0 && req->newptr != NULL) {
 478                 fence = newstr + (n < req->newlen ? n : req->newlen + 1);
 479                 if ((error = pmc_debugflags_parse(newstr, fence)) == 0)
 480                         (void) strlcpy(pmc_debugstr, newstr,
 481                             sizeof(pmc_debugstr));
 482         }
 483
 484         free(newstr, M_PMC);
 485
 486         return error;
 487 }
 488 #endif
 489
 490 /*
 491  * Map a row index to a classdep structure and return the adjusted row
 492  * index for the PMC class index.
 493  */
 494 static struct pmc_classdep *
 495 pmc_ri_to_classdep(struct pmc_mdep *md, int ri, int *adjri)
 496 {
 497         struct pmc_classdep *pcd;
 498
 499         (void) md;
 500
 501         KASSERT(ri >= 0 && ri < md->pmd_npmc,
 502             ("[pmc,%d] illegal row-index %d", __LINE__, ri));
 503
 504         pcd = pmc_rowindex_to_classdep[ri];
 505
 506         KASSERT(pcd != NULL,
 507             ("[amd,%d] ri %d null pcd", __LINE__, ri));
 508
 509         *adjri = ri - pcd->pcd_ri;
 510
 511         KASSERT(*adjri >= 0 && *adjri < pcd->pcd_num,
 512             ("[pmc,%d] adjusted row-index %d", __LINE__, *adjri));
 513
 514         return (pcd);
 515 }
 516
 517 /*
 518  * Concurrency Control
 519  *
 520  * The driver manages the following data structures:
 521  *
 522  *   - target process descriptors, one per target process
 523  *   - owner process descriptors (and attached lists), one per owner process
 524  *   - lookup hash tables for owner and target processes
 525  *   - PMC descriptors (and attached lists)
 526  *   - per-cpu hardware state
 527  *   - the 'hook' variable through which the kernel calls into
 528  *     this module
 529  *   - the machine hardware state (managed by the MD layer)
 530  *
 531  * These data structures are accessed from:
 532  *
 533  * - thread context-switch code
 534  * - interrupt handlers (possibly on multiple cpus)
 535  * - kernel threads on multiple cpus running on behalf of user
 536  *   processes doing system calls
 537  * - this driver's private kernel threads
 538  *
 539  * = Locks and Locking strategy =
 540  *
 541  * The driver uses four locking strategies for its operation:
 542  *
 543  * - The global SX lock "pmc_sx" is used to protect internal
 544  *   data structures.
 545  *
 546  *   Calls into the module by syscall() start with this lock being
 547  *   held in exclusive mode.  Depending on the requested operation,
 548  *   the lock may be downgraded to 'shared' mode to allow more
 549  *   concurrent readers into the module.  Calls into the module from
 550  *   other parts of the kernel acquire the lock in shared mode.
 551  *
 552  *   This SX lock is held in exclusive mode for any operations that
 553  *   modify the linkages between the driver's internal data structures.
 554  *
 555  *   The 'pmc_hook' function pointer is also protected by this lock.
 556  *   It is only examined with the sx lock held in exclusive mode.  The
 557  *   kernel module is allowed to be unloaded only with the sx lock held
 558  *   in exclusive mode.  In normal syscall handling, after acquiring the
 559  *   pmc_sx lock we first check that 'pmc_hook' is non-null before
 560  *   proceeding.  This prevents races between the thread unloading the module
 561  *   and other threads seeking to use the module.
 562  *
 563  * - Lookups of target process structures and owner process structures
 564  *   cannot use the global "pmc_sx" SX lock because these lookups need
 565  *   to happen during context switches and in other critical sections
 566  *   where sleeping is not allowed.  We protect these lookup tables
 567  *   with their own private spin-mutexes, "pmc_processhash_mtx" and
 568  *   "pmc_ownerhash_mtx".
 569  *
 570  * - Interrupt handlers work in a lock free manner.  At interrupt
 571  *   time, handlers look at the PMC pointer (phw->phw_pmc) configured
 572  *   when the PMC was started.  If this pointer is NULL, the interrupt
 573  *   is ignored after updating driver statistics.  We ensure that this
 574  *   pointer is set (using an atomic operation if necessary) before the
 575  *   PMC hardware is started.  Conversely, this pointer is unset atomically
 576  *   only after the PMC hardware is stopped.
 577  *
 578  *   We ensure that everything needed for the operation of an
 579  *   interrupt handler is available without it needing to acquire any
 580  *   locks.  We also ensure that a PMC's software state is destroyed only
 581  *   after the PMC is taken off hardware (on all CPUs).
 582  *
 583  * - Context-switch handling with process-private PMCs needs more
 584  *   care.
 585  *
 586  *   A given process may be the target of multiple PMCs.  For example,
 587  *   PMCATTACH and PMCDETACH may be requested by a process on one CPU
 588  *   while the target process is running on another.  A PMC could also
 589  *   be getting released because its owner is exiting.  We tackle
 590  *   these situations in the following manner:
 591  *
 592  *   - each target process structure 'pmc_process' has an array
 593  *     of 'struct pmc *' pointers, one for each hardware PMC.
 594  *
 595  *   - At context switch IN time, each "target" PMC in RUNNING state
 596  *     gets started on hardware and a pointer to each PMC is copied into
 597  *     the per-cpu phw array.  The 'runcount' for the PMC is
 598  *     incremented.
 599  *
 600  *   - At context switch OUT time, all process-virtual PMCs are stopped
 601  *     on hardware.  The saved value is added to the PMCs value field
 602  *     only if the PMC is in a non-deleted state (the PMCs state could
 603  *     have changed during the current time slice).
 604  *
 605  *     Note that since in-between a switch IN on a processor and a switch
 606  *     OUT, the PMC could have been released on another CPU.  Therefore
 607  *     context switch OUT always looks at the hardware state to turn
 608  *     OFF PMCs and will update a PMC's saved value only if reachable
 609  *     from the target process record.
 610  *
 611  *   - OP PMCRELEASE could be called on a PMC at any time (the PMC could
 612  *     be attached to many processes at the time of the call and could
 613  *     be active on multiple CPUs).
 614  *
 615  *     We prevent further scheduling of the PMC by marking it as in
 616  *     state 'DELETED'.  If the runcount of the PMC is non-zero then
 617  *     this PMC is currently running on a CPU somewhere.  The thread
 618  *     doing the PMCRELEASE operation waits by repeatedly doing a
 619  *     pause() till the runcount comes to zero.
 620  *
 621  * The contents of a PMC descriptor (struct pmc) are protected using
 622  * a spin-mutex.  In order to save space, we use a mutex pool.
 623  *
 624  * In terms of lock types used by witness(4), we use:
 625  * - Type "pmc-sx", used by the global SX lock.
 626  * - Type "pmc-sleep", for sleep mutexes used by logger threads.
 627  * - Type "pmc-per-proc", for protecting PMC owner descriptors.
 628  * - Type "pmc-leaf", used for all other spin mutexes.
 629  */
 630
 631 /*
 632  * save the cpu binding of the current kthread
 633  */
 634
 635 static void
 636 pmc_save_cpu_binding(struct pmc_binding *pb)
 637 {
 638         PMCDBG(CPU,BND,2, "%s", "save-cpu");
 639         thread_lock(curthread);
 640         pb->pb_bound = sched_is_bound(curthread);
 641         pb->pb_cpu   = curthread->td_oncpu;
 642         thread_unlock(curthread);
 643         PMCDBG(CPU,BND,2, "save-cpu cpu=%d", pb->pb_cpu);
 644 }
 645
 646 /*
 647  * restore the cpu binding of the current thread
 648  */
 649
 650 static void
 651 pmc_restore_cpu_binding(struct pmc_binding *pb)
 652 {
 653         PMCDBG(CPU,BND,2, "restore-cpu curcpu=%d restore=%d",
 654             curthread->td_oncpu, pb->pb_cpu);
 655         thread_lock(curthread);
 656         if (pb->pb_bound)
 657                 sched_bind(curthread, pb->pb_cpu);
 658         else
 659                 sched_unbind(curthread);
 660         thread_unlock(curthread);
 661         PMCDBG(CPU,BND,2, "%s", "restore-cpu done");
 662 }
 663
 664 /*
 665  * move execution over the specified cpu and bind it there.
 666  */
 667
 668 static void
 669 pmc_select_cpu(int cpu)
 670 {
 671         KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
 672             ("[pmc,%d] bad cpu number %d", __LINE__, cpu));
 673
 674         /* Never move to an inactive CPU. */
 675         KASSERT(pmc_cpu_is_active(cpu), ("[pmc,%d] selecting inactive "
 676             "CPU %d", __LINE__, cpu));
 677
 678         PMCDBG(CPU,SEL,2, "select-cpu cpu=%d", cpu);
 679         thread_lock(curthread);
 680         sched_bind(curthread, cpu);
 681         thread_unlock(curthread);
 682
 683         KASSERT(curthread->td_oncpu == cpu,
 684             ("[pmc,%d] CPU not bound [cpu=%d, curr=%d]", __LINE__,
 685                 cpu, curthread->td_oncpu));
 686
 687         PMCDBG(CPU,SEL,2, "select-cpu cpu=%d ok", cpu);
 688 }
 689
 690 /*
 691  * Force a context switch.
 692  *
 693  * We do this by pause'ing for 1 tick -- invoking mi_switch() is not
 694  * guaranteed to force a context switch.
 695  */
 696
 697 static void
 698 pmc_force_context_switch(void)
 699 {
 700
 701         pause("pmcctx", 1);
 702 }
 703
 704 /*
 705  * Get the file name for an executable.  This is a simple wrapper
 706  * around vn_fullpath(9).
 707  */
 708
 709 static void
 710 pmc_getfilename(struct vnode *v, char **fullpath, char **freepath)
 711 {
 712
 713         *fullpath = "unknown";
 714         *freepath = NULL;
 715         vn_fullpath(curthread, v, fullpath, freepath);
 716 }
 717
 718 /*
 719  * remove an process owning PMCs
 720  */
 721
 722 void
 723 pmc_remove_owner(struct pmc_owner *po)
 724 {
 725         struct pmc *pm, *tmp;
 726
 727         sx_assert(&pmc_sx, SX_XLOCKED);
 728
 729         PMCDBG(OWN,ORM,1, "remove-owner po=%p", po);
 730
 731         /* Remove descriptor from the owner hash table */
 732         LIST_REMOVE(po, po_next);
 733
 734         /* release all owned PMC descriptors */
 735         LIST_FOREACH_SAFE(pm, &po->po_pmcs, pm_next, tmp) {
 736                 PMCDBG(OWN,ORM,2, "pmc=%p", pm);
 737                 KASSERT(pm->pm_owner == po,
 738                     ("[pmc,%d] owner %p != po %p", __LINE__, pm->pm_owner, po));
 739
 740                 pmc_release_pmc_descriptor(pm); /* will unlink from the list */
 741         }
 742
 743         KASSERT(po->po_sscount == 0,
 744             ("[pmc,%d] SS count not zero", __LINE__));
 745         KASSERT(LIST_EMPTY(&po->po_pmcs),
 746             ("[pmc,%d] PMC list not empty", __LINE__));
 747
 748         /* de-configure the log file if present */
 749         if (po->po_flags & PMC_PO_OWNS_LOGFILE)
 750                 pmclog_deconfigure_log(po);
 751 }
 752
 753 /*
 754  * remove an owner process record if all conditions are met.
 755  */
 756
 757 static void
 758 pmc_maybe_remove_owner(struct pmc_owner *po)
 759 {
 760
 761         PMCDBG(OWN,OMR,1, "maybe-remove-owner po=%p", po);
 762
 763         /*
 764          * Remove owner record if
 765          * - this process does not own any PMCs
 766          * - this process has not allocated a system-wide sampling buffer
 767          */
 768
 769         if (LIST_EMPTY(&po->po_pmcs) &&
 770             ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)) {
 771                 pmc_remove_owner(po);
 772                 pmc_destroy_owner_descriptor(po);
 773         }
 774 }
 775
 776 /*
 777  * Add an association between a target process and a PMC.
 778  */
 779
 780 static void
 781 pmc_link_target_process(struct pmc *pm, struct pmc_process *pp)
 782 {
 783         int ri;
 784         struct pmc_target *pt;
 785
 786         sx_assert(&pmc_sx, SX_XLOCKED);
 787
 788         KASSERT(pm != NULL && pp != NULL,
 789             ("[pmc,%d] Null pm %p or pp %p", __LINE__, pm, pp));
 790         KASSERT(PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)),
 791             ("[pmc,%d] Attaching a non-process-virtual pmc=%p to pid=%d",
 792                 __LINE__, pm, pp->pp_proc->p_pid));
 793         KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt < ((int) md->pmd_npmc - 1),
 794             ("[pmc,%d] Illegal reference count %d for process record %p",
 795                 __LINE__, pp->pp_refcnt, (void *) pp));
 796
 797         ri = PMC_TO_ROWINDEX(pm);
 798
 799         PMCDBG(PRC,TLK,1, "link-target pmc=%p ri=%d pmc-process=%p",
 800             pm, ri, pp);
 801
 802 #ifdef  DEBUG
 803         LIST_FOREACH(pt, &pm->pm_targets, pt_next)
 804             if (pt->pt_process == pp)
 805                     KASSERT(0, ("[pmc,%d] pp %p already in pmc %p targets",
 806                                 __LINE__, pp, pm));
 807 #endif
 808
 809         pt = malloc(sizeof(struct pmc_target), M_PMC, M_WAITOK|M_ZERO);
 810         pt->pt_process = pp;
 811
 812         LIST_INSERT_HEAD(&pm->pm_targets, pt, pt_next);
 813
 814         atomic_store_rel_ptr((uintptr_t *)&pp->pp_pmcs[ri].pp_pmc,
 815             (uintptr_t)pm);
 816
 817         if (pm->pm_owner->po_owner == pp->pp_proc)
 818                 pm->pm_flags |= PMC_F_ATTACHED_TO_OWNER;
 819
 820         /*
 821          * Initialize the per-process values at this row index.
 822          */
 823         pp->pp_pmcs[ri].pp_pmcval = PMC_TO_MODE(pm) == PMC_MODE_TS ?
 824             pm->pm_sc.pm_reloadcount : 0;
 825
 826         pp->pp_refcnt++;
 827
 828 }
 829
 830 /*
 831  * Removes the association between a target process and a PMC.
 832  */
 833
 834 static void
 835 pmc_unlink_target_process(struct pmc *pm, struct pmc_process *pp)
 836 {
 837         int ri;
 838         struct proc *p;
 839         struct pmc_target *ptgt;
 840
 841         sx_assert(&pmc_sx, SX_XLOCKED);
 842
 843         KASSERT(pm != NULL && pp != NULL,
 844             ("[pmc,%d] Null pm %p or pp %p", __LINE__, pm, pp));
 845
 846         KASSERT(pp->pp_refcnt >= 1 && pp->pp_refcnt < (int) md->pmd_npmc,
 847             ("[pmc,%d] Illegal ref count %d on process record %p",
 848                 __LINE__, pp->pp_refcnt, (void *) pp));
 849
 850         ri = PMC_TO_ROWINDEX(pm);
 851
 852         PMCDBG(PRC,TUL,1, "unlink-target pmc=%p ri=%d pmc-process=%p",
 853             pm, ri, pp);
 854
 855         KASSERT(pp->pp_pmcs[ri].pp_pmc == pm,
 856             ("[pmc,%d] PMC ri %d mismatch pmc %p pp->[ri] %p", __LINE__,
 857                 ri, pm, pp->pp_pmcs[ri].pp_pmc));
 858
 859         pp->pp_pmcs[ri].pp_pmc = NULL;
 860         pp->pp_pmcs[ri].pp_pmcval = (pmc_value_t) 0;
 861
 862         /* Remove owner-specific flags */
 863         if (pm->pm_owner->po_owner == pp->pp_proc) {
 864                 pp->pp_flags &= ~PMC_PP_ENABLE_MSR_ACCESS;
 865                 pm->pm_flags &= ~PMC_F_ATTACHED_TO_OWNER;
 866         }
 867
 868         pp->pp_refcnt--;
 869
 870         /* Remove the target process from the PMC structure */
 871         LIST_FOREACH(ptgt, &pm->pm_targets, pt_next)
 872                 if (ptgt->pt_process == pp)
 873                         break;
 874
 875         KASSERT(ptgt != NULL, ("[pmc,%d] process %p (pp: %p) not found "
 876                     "in pmc %p", __LINE__, pp->pp_proc, pp, pm));
 877
 878         LIST_REMOVE(ptgt, pt_next);
 879         free(ptgt, M_PMC);
 880
 881         /* if the PMC now lacks targets, send the owner a SIGIO */
 882         if (LIST_EMPTY(&pm->pm_targets)) {
 883                 p = pm->pm_owner->po_owner;
 884                 PROC_LOCK(p);
 885                 psignal(p, SIGIO);
 886                 PROC_UNLOCK(p);
 887
 888                 PMCDBG(PRC,SIG,2, "signalling proc=%p signal=%d", p,
 889                     SIGIO);
 890         }
 891 }
 892
 893 /*
 894  * Check if PMC 'pm' may be attached to target process 't'.
 895  */
 896
 897 static int
 898 pmc_can_attach(struct pmc *pm, struct proc *t)
 899 {
 900         struct proc *o;         /* pmc owner */
 901         struct ucred *oc, *tc;  /* owner, target credentials */
 902         int decline_attach, i;
 903
 904         /*
 905          * A PMC's owner can always attach that PMC to itself.
 906          */
 907
 908         if ((o = pm->pm_owner->po_owner) == t)
 909                 return 0;
 910
 911         PROC_LOCK(o);
 912         oc = o->p_ucred;
 913         crhold(oc);
 914         PROC_UNLOCK(o);
 915
 916         PROC_LOCK(t);
 917         tc = t->p_ucred;
 918         crhold(tc);
 919         PROC_UNLOCK(t);
 920
 921         /*
 922          * The effective uid of the PMC owner should match at least one
 923          * of the {effective,real,saved} uids of the target process.
 924          */
 925
 926         decline_attach = oc->cr_uid != tc->cr_uid &&
 927             oc->cr_uid != tc->cr_svuid &&
 928             oc->cr_uid != tc->cr_ruid;
 929
 930         /*
 931          * Every one of the target's group ids, must be in the owner's
 932          * group list.
 933          */
 934         for (i = 0; !decline_attach && i < tc->cr_ngroups; i++)
 935                 decline_attach = !groupmember(tc->cr_groups[i], oc);
 936
 937         /* check the read and saved gids too */
 938         if (decline_attach == 0)
 939                 decline_attach = !groupmember(tc->cr_rgid, oc) ||
 940                     !groupmember(tc->cr_svgid, oc);
 941
 942         crfree(tc);
 943         crfree(oc);
 944
 945         return !decline_attach;
 946 }
 947
 948 /*
 949  * Attach a process to a PMC.
 950  */
 951
 952 static int
 953 pmc_attach_one_process(struct proc *p, struct pmc *pm)
 954 {
 955         int ri;
 956         char *fullpath, *freepath;
 957         struct pmc_process      *pp;
 958
 959         sx_assert(&pmc_sx, SX_XLOCKED);
 960
 961         PMCDBG(PRC,ATT,2, "attach-one pm=%p ri=%d proc=%p (%d, %s)", pm,
 962             PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
 963
 964         /*
 965          * Locate the process descriptor corresponding to process 'p',
 966          * allocating space as needed.
 967          *
 968          * Verify that rowindex 'pm_rowindex' is free in the process
 969          * descriptor.
 970          *
 971          * If not, allocate space for a descriptor and link the
 972          * process descriptor and PMC.
 973          */
 974         ri = PMC_TO_ROWINDEX(pm);
 975
 976         if ((pp = pmc_find_process_descriptor(p, PMC_FLAG_ALLOCATE)) == NULL)
 977                 return ENOMEM;
 978
 979         if (pp->pp_pmcs[ri].pp_pmc == pm) /* already present at slot [ri] */
 980                 return EEXIST;
 981
 982         if (pp->pp_pmcs[ri].pp_pmc != NULL)
 983                 return EBUSY;
 984
 985         pmc_link_target_process(pm, pp);
 986
 987         if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)) &&
 988             (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) == 0)
 989                 pm->pm_flags |= PMC_F_NEEDS_LOGFILE;
 990
 991         pm->pm_flags |= PMC_F_ATTACH_DONE; /* mark as attached */
 992
 993         /* issue an attach event to a configured log file */
 994         if (pm->pm_owner->po_flags & PMC_PO_OWNS_LOGFILE) {
 995                 pmc_getfilename(p->p_textvp, &fullpath, &freepath);
 996                 if (p->p_flag & P_KTHREAD) {
 997                         fullpath = kernelname;
 998                         freepath = NULL;
 999                 } else
1000                         pmclog_process_pmcattach(pm, p->p_pid, fullpath);
1001                 if (freepath)
1002                         free(freepath, M_TEMP);
1003                 if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
1004                         pmc_log_process_mappings(pm->pm_owner, p);
1005         }
1006         /* mark process as using HWPMCs */
1007         PROC_LOCK(p);
1008         p->p_flag |= P_HWPMC;
1009         PROC_UNLOCK(p);
1010
1011         return 0;
1012 }
1013
1014 /*
1015  * Attach a process and optionally its children
1016  */
1017
1018 static int
1019 pmc_attach_process(struct proc *p, struct pmc *pm)
1020 {
1021         int error;
1022         struct proc *top;
1023
1024         sx_assert(&pmc_sx, SX_XLOCKED);
1025
1026         PMCDBG(PRC,ATT,1, "attach pm=%p ri=%d proc=%p (%d, %s)", pm,
1027             PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
1028
1029
1030         /*
1031          * If this PMC successfully allowed a GETMSR operation
1032          * in the past, disallow further ATTACHes.
1033          */
1034
1035         if ((pm->pm_flags & PMC_PP_ENABLE_MSR_ACCESS) != 0)
1036                 return EPERM;
1037
1038         if ((pm->pm_flags & PMC_F_DESCENDANTS) == 0)
1039                 return pmc_attach_one_process(p, pm);
1040
1041         /*
1042          * Traverse all child processes, attaching them to
1043          * this PMC.
1044          */
1045
1046         sx_slock(&proctree_lock);
1047
1048         top = p;
1049
1050         for (;;) {
1051                 if ((error = pmc_attach_one_process(p, pm)) != 0)
1052                         break;
1053                 if (!LIST_EMPTY(&p->p_children))
1054                         p = LIST_FIRST(&p->p_children);
1055                 else for (;;) {
1056                         if (p == top)
1057                                 goto done;
1058                         if (LIST_NEXT(p, p_sibling)) {
1059                                 p = LIST_NEXT(p, p_sibling);
1060                                 break;
1061                         }
1062                         p = p->p_pptr;
1063                 }
1064         }
1065
1066         if (error)
1067                 (void) pmc_detach_process(top, pm);
1068
1069  done:
1070         sx_sunlock(&proctree_lock);
1071         return error;
1072 }
1073
1074 /*
1075  * Detach a process from a PMC.  If there are no other PMCs tracking
1076  * this process, remove the process structure from its hash table.  If
1077  * 'flags' contains PMC_FLAG_REMOVE, then free the process structure.
1078  */
1079
1080 static int
1081 pmc_detach_one_process(struct proc *p, struct pmc *pm, int flags)
1082 {
1083         int ri;
1084         struct pmc_process *pp;
1085
1086         sx_assert(&pmc_sx, SX_XLOCKED);
1087
1088         KASSERT(pm != NULL,
1089             ("[pmc,%d] null pm pointer", __LINE__));
1090
1091         ri = PMC_TO_ROWINDEX(pm);
1092
1093         PMCDBG(PRC,ATT,2, "detach-one pm=%p ri=%d proc=%p (%d, %s) flags=0x%x",
1094             pm, ri, p, p->p_pid, p->p_comm, flags);
1095
1096         if ((pp = pmc_find_process_descriptor(p, 0)) == NULL)
1097                 return ESRCH;
1098
1099         if (pp->pp_pmcs[ri].pp_pmc != pm)
1100                 return EINVAL;
1101
1102         pmc_unlink_target_process(pm, pp);
1103
1104         /* Issue a detach entry if a log file is configured */
1105         if (pm->pm_owner->po_flags & PMC_PO_OWNS_LOGFILE)
1106                 pmclog_process_pmcdetach(pm, p->p_pid);
1107
1108         /*
1109          * If there are no PMCs targetting this process, we remove its
1110          * descriptor from the target hash table and unset the P_HWPMC
1111          * flag in the struct proc.
1112          */
1113         KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt < (int) md->pmd_npmc,
1114             ("[pmc,%d] Illegal refcnt %d for process struct %p",
1115                 __LINE__, pp->pp_refcnt, pp));
1116
1117         if (pp->pp_refcnt != 0) /* still a target of some PMC */
1118                 return 0;
1119
1120         pmc_remove_process_descriptor(pp);
1121
1122         if (flags & PMC_FLAG_REMOVE)
1123                 free(pp, M_PMC);
1124
1125         PROC_LOCK(p);
1126         p->p_flag &= ~P_HWPMC;
1127         PROC_UNLOCK(p);
1128
1129         return 0;
1130 }
1131
1132 /*
1133  * Detach a process and optionally its descendants from a PMC.
1134  */
1135
1136 static int
1137 pmc_detach_process(struct proc *p, struct pmc *pm)
1138 {
1139         struct proc *top;
1140
1141         sx_assert(&pmc_sx, SX_XLOCKED);
1142
1143         PMCDBG(PRC,ATT,1, "detach pm=%p ri=%d proc=%p (%d, %s)", pm,
1144             PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
1145
1146         if ((pm->pm_flags & PMC_F_DESCENDANTS) == 0)
1147                 return pmc_detach_one_process(p, pm, PMC_FLAG_REMOVE);
1148
1149         /*
1150          * Traverse all children, detaching them from this PMC.  We
1151          * ignore errors since we could be detaching a PMC from a
1152          * partially attached proc tree.
1153          */
1154
1155         sx_slock(&proctree_lock);
1156
1157         top = p;
1158
1159         for (;;) {
1160                 (void) pmc_detach_one_process(p, pm, PMC_FLAG_REMOVE);
1161
1162                 if (!LIST_EMPTY(&p->p_children))
1163                         p = LIST_FIRST(&p->p_children);
1164                 else for (;;) {
1165                         if (p == top)
1166                                 goto done;
1167                         if (LIST_NEXT(p, p_sibling)) {
1168                                 p = LIST_NEXT(p, p_sibling);
1169                                 break;
1170                         }
1171                         p = p->p_pptr;
1172                 }
1173         }
1174
1175  done:
1176         sx_sunlock(&proctree_lock);
1177
1178         if (LIST_EMPTY(&pm->pm_targets))
1179                 pm->pm_flags &= ~PMC_F_ATTACH_DONE;
1180
1181         return 0;
1182 }
1183
1184
1185 /*
1186  * Thread context switch IN
1187  */
1188
1189 static void
1190 pmc_process_csw_in(struct thread *td)
1191 {
1192         int cpu;
1193         unsigned int adjri, ri;
1194         struct pmc *pm;
1195         struct proc *p;
1196         struct pmc_cpu *pc;
1197         struct pmc_hw *phw;
1198         pmc_value_t newvalue;
1199         struct pmc_process *pp;
1200         struct pmc_classdep *pcd;
1201
1202         p = td->td_proc;
1203
1204         if ((pp = pmc_find_process_descriptor(p, PMC_FLAG_NONE)) == NULL)
1205                 return;
1206
1207         KASSERT(pp->pp_proc == td->td_proc,
1208             ("[pmc,%d] not my thread state", __LINE__));
1209
1210         critical_enter(); /* no preemption from this point */
1211
1212         cpu = PCPU_GET(cpuid); /* td->td_oncpu is invalid */
1213
1214         PMCDBG(CSW,SWI,1, "cpu=%d proc=%p (%d, %s) pp=%p", cpu, p,
1215             p->p_pid, p->p_comm, pp);
1216
1217         KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
1218             ("[pmc,%d] wierd CPU id %d", __LINE__, cpu));
1219
1220         pc = pmc_pcpu[cpu];
1221
1222         for (ri = 0; ri < md->pmd_npmc; ri++) {
1223
1224                 if ((pm = pp->pp_pmcs[ri].pp_pmc) == NULL)
1225                         continue;
1226
1227                 KASSERT(PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)),
1228                     ("[pmc,%d] Target PMC in non-virtual mode (%d)",
1229                         __LINE__, PMC_TO_MODE(pm)));
1230
1231                 KASSERT(PMC_TO_ROWINDEX(pm) == ri,
1232                     ("[pmc,%d] Row index mismatch pmc %d != ri %d",
1233                         __LINE__, PMC_TO_ROWINDEX(pm), ri));
1234
1235                 /*
1236                  * Only PMCs that are marked as 'RUNNING' need
1237                  * be placed on hardware.
1238                  */
1239
1240                 if (pm->pm_state != PMC_STATE_RUNNING)
1241                         continue;
1242
1243                 /* increment PMC runcount */
1244                 atomic_add_rel_32(&pm->pm_runcount, 1);
1245
1246                 /* configure the HWPMC we are going to use. */
1247                 pcd = pmc_ri_to_classdep(md, ri, &adjri);
1248                 pcd->pcd_config_pmc(cpu, adjri, pm);
1249
1250                 phw = pc->pc_hwpmcs[ri];
1251
1252                 KASSERT(phw != NULL,
1253                     ("[pmc,%d] null hw pointer", __LINE__));
1254
1255                 KASSERT(phw->phw_pmc == pm,
1256                     ("[pmc,%d] hw->pmc %p != pmc %p", __LINE__,
1257                         phw->phw_pmc, pm));
1258
1259                 /*
1260                  * Write out saved value and start the PMC.
1261                  *
1262                  * Sampling PMCs use a per-process value, while
1263                  * counting mode PMCs use a per-pmc value that is
1264                  * inherited across descendants.
1265                  */
1266                 if (PMC_TO_MODE(pm) == PMC_MODE_TS) {
1267                         mtx_pool_lock_spin(pmc_mtxpool, pm);
1268                         newvalue = PMC_PCPU_SAVED(cpu,ri) =
1269                             pp->pp_pmcs[ri].pp_pmcval;
1270                         mtx_pool_unlock_spin(pmc_mtxpool, pm);
1271                 } else {
1272                         KASSERT(PMC_TO_MODE(pm) == PMC_MODE_TC,
1273                             ("[pmc,%d] illegal mode=%d", __LINE__,
1274                             PMC_TO_MODE(pm)));
1275                         mtx_pool_lock_spin(pmc_mtxpool, pm);
1276                         newvalue = PMC_PCPU_SAVED(cpu, ri) =
1277                             pm->pm_gv.pm_savedvalue;
1278                         mtx_pool_unlock_spin(pmc_mtxpool, pm);
1279                 }
1280
1281                 PMCDBG(CSW,SWI,1,"cpu=%d ri=%d new=%jd", cpu, ri, newvalue);
1282
1283                 pcd->pcd_write_pmc(cpu, adjri, newvalue);
1284                 pcd->pcd_start_pmc(cpu, adjri);
1285         }
1286
1287         /*
1288          * perform any other architecture/cpu dependent thread
1289          * switch-in actions.
1290          */
1291
1292         (void) (*md->pmd_switch_in)(pc, pp);
1293
1294         critical_exit();
1295
1296 }
1297
1298 /*
1299  * Thread context switch OUT.
1300  */
1301
1302 static void
1303 pmc_process_csw_out(struct thread *td)
1304 {
1305         int cpu;
1306         int64_t tmp;
1307         struct pmc *pm;
1308         struct proc *p;
1309         enum pmc_mode mode;
1310         struct pmc_cpu *pc;
1311         pmc_value_t newvalue;
1312         unsigned int adjri, ri;
1313         struct pmc_process *pp;
1314         struct pmc_classdep *pcd;
1315
1316
1317         /*
1318          * Locate our process descriptor; this may be NULL if
1319          * this process is exiting and we have already removed
1320          * the process from the target process table.
1321          *
1322          * Note that due to kernel preemption, multiple
1323          * context switches may happen while the process is
1324          * exiting.
1325          *
1326          * Note also that if the target process cannot be
1327          * found we still need to deconfigure any PMCs that
1328          * are currently running on hardware.
1329          */
1330
1331         p = td->td_proc;
1332         pp = pmc_find_process_descriptor(p, PMC_FLAG_NONE);
1333
1334         /*
1335          * save PMCs
1336          */
1337
1338         critical_enter();
1339
1340         cpu = PCPU_GET(cpuid); /* td->td_oncpu is invalid */
1341
1342         PMCDBG(CSW,SWO,1, "cpu=%d proc=%p (%d, %s) pp=%p", cpu, p,
1343             p->p_pid, p->p_comm, pp);
1344
1345         KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
1346             ("[pmc,%d wierd CPU id %d", __LINE__, cpu));
1347
1348         pc = pmc_pcpu[cpu];
1349
1350         /*
1351          * When a PMC gets unlinked from a target PMC, it will
1352          * be removed from the target's pp_pmc[] array.
1353          *
1354          * However, on a MP system, the target could have been
1355          * executing on another CPU at the time of the unlink.
1356          * So, at context switch OUT time, we need to look at
1357          * the hardware to determine if a PMC is scheduled on
1358          * it.
1359          */
1360
1361         for (ri = 0; ri < md->pmd_npmc; ri++) {
1362
1363                 pcd = pmc_ri_to_classdep(md, ri, &adjri);
1364                 pm  = NULL;
1365                 (void) (*pcd->pcd_get_config)(cpu, adjri, &pm);
1366
1367                 if (pm == NULL) /* nothing at this row index */
1368                         continue;
1369
1370                 mode = PMC_TO_MODE(pm);
1371                 if (!PMC_IS_VIRTUAL_MODE(mode))
1372                         continue; /* not a process virtual PMC */
1373
1374                 KASSERT(PMC_TO_ROWINDEX(pm) == ri,
1375                     ("[pmc,%d] ri mismatch pmc(%d) ri(%d)",
1376                         __LINE__, PMC_TO_ROWINDEX(pm), ri));
1377
1378                 /* Stop hardware if not already stopped */
1379                 if (pm->pm_stalled == 0)
1380                         pcd->pcd_stop_pmc(cpu, adjri);
1381
1382                 /* reduce this PMC's runcount */
1383                 atomic_subtract_rel_32(&pm->pm_runcount, 1);
1384
1385                 /*
1386                  * If this PMC is associated with this process,
1387                  * save the reading.
1388                  */
1389
1390                 if (pp != NULL && pp->pp_pmcs[ri].pp_pmc != NULL) {
1391
1392                         KASSERT(pm == pp->pp_pmcs[ri].pp_pmc,
1393                             ("[pmc,%d] pm %p != pp_pmcs[%d] %p", __LINE__,
1394                                 pm, ri, pp->pp_pmcs[ri].pp_pmc));
1395
1396                         KASSERT(pp->pp_refcnt > 0,
1397                             ("[pmc,%d] pp refcnt = %d", __LINE__,
1398                                 pp->pp_refcnt));
1399
1400                         pcd->pcd_read_pmc(cpu, adjri, &newvalue);
1401
1402                         tmp = newvalue - PMC_PCPU_SAVED(cpu,ri);
1403
1404                         PMCDBG(CSW,SWI,1,"cpu=%d ri=%d tmp=%jd", cpu, ri,
1405                             tmp);
1406
1407                         if (mode == PMC_MODE_TS) {
1408
1409                                 /*
1410                                  * For sampling process-virtual PMCs,
1411                                  * we expect the count to be
1412                                  * decreasing as the 'value'
1413                                  * programmed into the PMC is the
1414                                  * number of events to be seen till
1415                                  * the next sampling interrupt.
1416                                  */
1417                                 if (tmp < 0)
1418                                         tmp += pm->pm_sc.pm_reloadcount;
1419                                 mtx_pool_lock_spin(pmc_mtxpool, pm);
1420                                 pp->pp_pmcs[ri].pp_pmcval -= tmp;
1421                                 if ((int64_t) pp->pp_pmcs[ri].pp_pmcval < 0)
1422                                         pp->pp_pmcs[ri].pp_pmcval +=
1423                                             pm->pm_sc.pm_reloadcount;
1424                                 mtx_pool_unlock_spin(pmc_mtxpool, pm);
1425
1426                         } else {
1427
1428                                 /*
1429                                  * For counting process-virtual PMCs,
1430                                  * we expect the count to be
1431                                  * increasing monotonically, modulo a 64
1432                                  * bit wraparound.
1433                                  */
1434                                 KASSERT((int64_t) tmp >= 0,
1435                                     ("[pmc,%d] negative increment cpu=%d "
1436                                      "ri=%d newvalue=%jx saved=%jx "
1437                                      "incr=%jx", __LINE__, cpu, ri,
1438                                      newvalue, PMC_PCPU_SAVED(cpu,ri), tmp));
1439
1440                                 mtx_pool_lock_spin(pmc_mtxpool, pm);
1441                                 pm->pm_gv.pm_savedvalue += tmp;
1442                                 pp->pp_pmcs[ri].pp_pmcval += tmp;
1443                                 mtx_pool_unlock_spin(pmc_mtxpool, pm);
1444
1445                                 if (pm->pm_flags & PMC_F_LOG_PROCCSW)
1446                                         pmclog_process_proccsw(pm, pp, tmp);
1447                         }
1448                 }
1449
1450                 /* mark hardware as free */
1451                 pcd->pcd_config_pmc(cpu, adjri, NULL);
1452         }
1453
1454         /*
1455          * perform any other architecture/cpu dependent thread
1456          * switch out functions.
1457          */
1458
1459         (void) (*md->pmd_switch_out)(pc, pp);
1460
1461         critical_exit();
1462 }
1463
1464 /*
1465  * Log a KLD operation.
1466  */
1467
1468 static void
1469 pmc_process_kld_load(struct pmckern_map_in *pkm)
1470 {
1471         struct pmc_owner *po;
1472
1473         sx_assert(&pmc_sx, SX_LOCKED);
1474
1475         /*
1476          * Notify owners of system sampling PMCs about KLD operations.
1477          */
1478
1479         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1480             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1481                 pmclog_process_map_in(po, (pid_t) -1, pkm->pm_address,
1482                     (char *) pkm->pm_file);
1483
1484         /*
1485          * TODO: Notify owners of (all) process-sampling PMCs too.
1486          */
1487
1488         return;
1489 }
1490
1491 static void
1492 pmc_process_kld_unload(struct pmckern_map_out *pkm)
1493 {
1494         struct pmc_owner *po;
1495
1496         sx_assert(&pmc_sx, SX_LOCKED);
1497
1498         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1499             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1500                 pmclog_process_map_out(po, (pid_t) -1,
1501                     pkm->pm_address, pkm->pm_address + pkm->pm_size);
1502
1503         /*
1504          * TODO: Notify owners of process-sampling PMCs.
1505          */
1506 }
1507
1508 /*
1509  * A mapping change for a process.
1510  */
1511
1512 static void
1513 pmc_process_mmap(struct thread *td, struct pmckern_map_in *pkm)
1514 {
1515         int ri;
1516         pid_t pid;
1517         char *fullpath, *freepath;
1518         const struct pmc *pm;
1519         struct pmc_owner *po;
1520         const struct pmc_process *pp;
1521
1522         freepath = fullpath = NULL;
1523         pmc_getfilename((struct vnode *) pkm->pm_file, &fullpath, &freepath);
1524
1525         pid = td->td_proc->p_pid;
1526
1527         /* Inform owners of all system-wide sampling PMCs. */
1528         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1529             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1530                 pmclog_process_map_in(po, pid, pkm->pm_address, fullpath);
1531
1532         if ((pp = pmc_find_process_descriptor(td->td_proc, 0)) == NULL)
1533                 goto done;
1534
1535         /*
1536          * Inform sampling PMC owners tracking this process.
1537          */
1538         for (ri = 0; ri < md->pmd_npmc; ri++)
1539                 if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL &&
1540                     PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
1541                         pmclog_process_map_in(pm->pm_owner,
1542                             pid, pkm->pm_address, fullpath);
1543
1544   done:
1545         if (freepath)
1546                 free(freepath, M_TEMP);
1547 }
1548
1549
1550 /*
1551  * Log an munmap request.
1552  */
1553
1554 static void
1555 pmc_process_munmap(struct thread *td, struct pmckern_map_out *pkm)
1556 {
1557         int ri;
1558         pid_t pid;
1559         struct pmc_owner *po;
1560         const struct pmc *pm;
1561         const struct pmc_process *pp;
1562
1563         pid = td->td_proc->p_pid;
1564
1565         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1566             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1567                 pmclog_process_map_out(po, pid, pkm->pm_address,
1568                     pkm->pm_address + pkm->pm_size);
1569
1570         if ((pp = pmc_find_process_descriptor(td->td_proc, 0)) == NULL)
1571                 return;
1572
1573         for (ri = 0; ri < md->pmd_npmc; ri++)
1574                 if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL &&
1575                     PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
1576                         pmclog_process_map_out(pm->pm_owner, pid,
1577                             pkm->pm_address, pkm->pm_address + pkm->pm_size);
1578 }
1579
1580 /*
1581  * Log mapping information about the kernel.
1582  */
1583
1584 static void
1585 pmc_log_kernel_mappings(struct pmc *pm)
1586 {
1587         struct pmc_owner *po;
1588         struct pmckern_map_in *km, *kmbase;
1589
1590         sx_assert(&pmc_sx, SX_LOCKED);
1591         KASSERT(PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)),
1592             ("[pmc,%d] non-sampling PMC (%p) desires mapping information",
1593                 __LINE__, (void *) pm));
1594
1595         po = pm->pm_owner;
1596
1597         if (po->po_flags & PMC_PO_INITIAL_MAPPINGS_DONE)
1598                 return;
1599
1600         /*
1601          * Log the current set of kernel modules.
1602          */
1603         kmbase = linker_hwpmc_list_objects();
1604         for (km = kmbase; km->pm_file != NULL; km++) {
1605                 PMCDBG(LOG,REG,1,"%s %p", (char *) km->pm_file,
1606                     (void *) km->pm_address);
1607                 pmclog_process_map_in(po, (pid_t) -1, km->pm_address,
1608                     km->pm_file);
1609         }
1610         free(kmbase, M_LINKER);
1611
1612         po->po_flags |= PMC_PO_INITIAL_MAPPINGS_DONE;
1613 }
1614
1615 /*
1616  * Log the mappings for a single process.
1617  */
1618
1619 static void
1620 pmc_log_process_mappings(struct pmc_owner *po, struct proc *p)
1621 {
1622 }
1623
1624 /*
1625  * Log mappings for all processes in the system.
1626  */
1627
1628 static void
1629 pmc_log_all_process_mappings(struct pmc_owner *po)
1630 {
1631         struct proc *p, *top;
1632
1633         sx_assert(&pmc_sx, SX_XLOCKED);
1634
1635         if ((p = pfind(1)) == NULL)
1636                 panic("[pmc,%d] Cannot find init", __LINE__);
1637
1638         PROC_UNLOCK(p);
1639
1640         sx_slock(&proctree_lock);
1641
1642         top = p;
1643
1644         for (;;) {
1645                 pmc_log_process_mappings(po, p);
1646                 if (!LIST_EMPTY(&p->p_children))
1647                         p = LIST_FIRST(&p->p_children);
1648                 else for (;;) {
1649                         if (p == top)
1650                                 goto done;
1651                         if (LIST_NEXT(p, p_sibling)) {
1652                                 p = LIST_NEXT(p, p_sibling);
1653                                 break;
1654                         }
1655                         p = p->p_pptr;
1656                 }
1657         }
1658  done:
1659         sx_sunlock(&proctree_lock);
1660 }
1661
1662 /*
1663  * The 'hook' invoked from the kernel proper
1664  */
1665
1666
1667 #ifdef  DEBUG
1668 const char *pmc_hooknames[] = {
1669         /* these strings correspond to PMC_FN_* in <sys/pmckern.h> */
1670         "",
1671         "EXEC",
1672         "CSW-IN",
1673         "CSW-OUT",
1674         "SAMPLE",
1675         "KLDLOAD",
1676         "KLDUNLOAD",
1677         "MMAP",
1678         "MUNMAP",
1679         "CALLCHAIN"
1680 };
1681 #endif
1682
1683 static int
1684 pmc_hook_handler(struct thread *td, int function, void *arg)
1685 {
1686
1687         PMCDBG(MOD,PMH,1, "hook td=%p func=%d \"%s\" arg=%p", td, function,
1688             pmc_hooknames[function], arg);
1689
1690         switch (function)
1691         {
1692
1693         /*
1694          * Process exec()
1695          */
1696
1697         case PMC_FN_PROCESS_EXEC:
1698         {
1699                 char *fullpath, *freepath;
1700                 unsigned int ri;
1701                 int is_using_hwpmcs;
1702                 struct pmc *pm;
1703                 struct proc *p;
1704                 struct pmc_owner *po;
1705                 struct pmc_process *pp;
1706                 struct pmckern_procexec *pk;
1707
1708                 sx_assert(&pmc_sx, SX_XLOCKED);
1709
1710                 p = td->td_proc;
1711                 pmc_getfilename(p->p_textvp, &fullpath, &freepath);
1712
1713                 pk = (struct pmckern_procexec *) arg;
1714
1715                 /* Inform owners of SS mode PMCs of the exec event. */
1716                 LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1717                     if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1718                             pmclog_process_procexec(po, PMC_ID_INVALID,
1719                                 p->p_pid, pk->pm_entryaddr, fullpath);
1720
1721                 PROC_LOCK(p);
1722                 is_using_hwpmcs = p->p_flag & P_HWPMC;
1723                 PROC_UNLOCK(p);
1724
1725                 if (!is_using_hwpmcs) {
1726                         if (freepath)
1727                                 free(freepath, M_TEMP);
1728                         break;
1729                 }
1730
1731                 /*
1732                  * PMCs are not inherited across an exec():  remove any
1733                  * PMCs that this process is the owner of.
1734                  */
1735
1736                 if ((po = pmc_find_owner_descriptor(p)) != NULL) {
1737                         pmc_remove_owner(po);
1738                         pmc_destroy_owner_descriptor(po);
1739                 }
1740
1741                 /*
1742                  * If the process being exec'ed is not the target of any
1743                  * PMC, we are done.
1744                  */
1745                 if ((pp = pmc_find_process_descriptor(p, 0)) == NULL) {
1746                         if (freepath)
1747                                 free(freepath, M_TEMP);
1748                         break;
1749                 }
1750
1751                 /*
1752                  * Log the exec event to all monitoring owners.  Skip
1753                  * owners who have already recieved the event because
1754                  * they had system sampling PMCs active.
1755                  */
1756                 for (ri = 0; ri < md->pmd_npmc; ri++)
1757                         if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL) {
1758                                 po = pm->pm_owner;
1759                                 if (po->po_sscount == 0 &&
1760                                     po->po_flags & PMC_PO_OWNS_LOGFILE)
1761                                         pmclog_process_procexec(po, pm->pm_id,
1762                                             p->p_pid, pk->pm_entryaddr,
1763                                             fullpath);
1764                         }
1765
1766                 if (freepath)
1767                         free(freepath, M_TEMP);
1768
1769
1770                 PMCDBG(PRC,EXC,1, "exec proc=%p (%d, %s) cred-changed=%d",
1771                     p, p->p_pid, p->p_comm, pk->pm_credentialschanged);
1772
1773                 if (pk->pm_credentialschanged == 0) /* no change */
1774                         break;
1775
1776                 /*
1777                  * If the newly exec()'ed process has a different credential
1778                  * than before, allow it to be the target of a PMC only if
1779                  * the PMC's owner has sufficient priviledge.
1780                  */
1781
1782                 for (ri = 0; ri < md->pmd_npmc; ri++)
1783                         if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL)
1784                                 if (pmc_can_attach(pm, td->td_proc) != 0)
1785                                         pmc_detach_one_process(td->td_proc,
1786                                             pm, PMC_FLAG_NONE);
1787
1788                 KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt < (int) md->pmd_npmc,
1789                     ("[pmc,%d] Illegal ref count %d on pp %p", __LINE__,
1790                         pp->pp_refcnt, pp));
1791
1792                 /*
1793                  * If this process is no longer the target of any
1794                  * PMCs, we can remove the process entry and free
1795                  * up space.
1796                  */
1797
1798                 if (pp->pp_refcnt == 0) {
1799                         pmc_remove_process_descriptor(pp);
1800                         free(pp, M_PMC);
1801                         break;
1802                 }
1803
1804         }
1805         break;
1806
1807         case PMC_FN_CSW_IN:
1808                 pmc_process_csw_in(td);
1809                 break;
1810
1811         case PMC_FN_CSW_OUT:
1812                 pmc_process_csw_out(td);
1813                 break;
1814
1815         /*
1816          * Process accumulated PC samples.
1817          *
1818          * This function is expected to be called by hardclock() for
1819          * each CPU that has accumulated PC samples.
1820          *
1821          * This function is to be executed on the CPU whose samples
1822          * are being processed.
1823          */
1824         case PMC_FN_DO_SAMPLES:
1825
1826                 /*
1827                  * Clear the cpu specific bit in the CPU mask before
1828                  * do the rest of the processing.  If the NMI handler
1829                  * gets invoked after the "atomic_clear_int()" call
1830                  * below but before "pmc_process_samples()" gets
1831                  * around to processing the interrupt, then we will
1832                  * come back here at the next hardclock() tick (and
1833                  * may find nothing to do if "pmc_process_samples()"
1834                  * had already processed the interrupt).  We don't
1835                  * lose the interrupt sample.
1836                  */
1837                 atomic_clear_int(&pmc_cpumask, (1 << PCPU_GET(cpuid)));
1838                 pmc_process_samples(PCPU_GET(cpuid));
1839                 break;
1840
1841
1842         case PMC_FN_KLD_LOAD:
1843                 sx_assert(&pmc_sx, SX_LOCKED);
1844                 pmc_process_kld_load((struct pmckern_map_in *) arg);
1845                 break;
1846
1847         case PMC_FN_KLD_UNLOAD:
1848                 sx_assert(&pmc_sx, SX_LOCKED);
1849                 pmc_process_kld_unload((struct pmckern_map_out *) arg);
1850                 break;
1851
1852         case PMC_FN_MMAP:
1853                 sx_assert(&pmc_sx, SX_LOCKED);
1854                 pmc_process_mmap(td, (struct pmckern_map_in *) arg);
1855                 break;
1856
1857         case PMC_FN_MUNMAP:
1858                 sx_assert(&pmc_sx, SX_LOCKED);
1859                 pmc_process_munmap(td, (struct pmckern_map_out *) arg);
1860                 break;
1861
1862         case PMC_FN_USER_CALLCHAIN:
1863                 /*
1864                  * Record a call chain.
1865                  */
1866                 KASSERT(td == curthread, ("[pmc,%d] td != curthread",
1867                     __LINE__));
1868                 pmc_capture_user_callchain(PCPU_GET(cpuid),
1869                     (struct trapframe *) arg);
1870                 td->td_pflags &= ~TDP_CALLCHAIN;
1871                 break;
1872
1873         default:
1874 #ifdef  DEBUG
1875                 KASSERT(0, ("[pmc,%d] unknown hook %d\n", __LINE__, function));
1876 #endif
1877                 break;
1878
1879         }
1880
1881         return 0;
1882 }
1883
1884 /*
1885  * allocate a 'struct pmc_owner' descriptor in the owner hash table.
1886  */
1887
1888 static struct pmc_owner *
1889 pmc_allocate_owner_descriptor(struct proc *p)
1890 {
1891         uint32_t hindex;
1892         struct pmc_owner *po;
1893         struct pmc_ownerhash *poh;
1894
1895         hindex = PMC_HASH_PTR(p, pmc_ownerhashmask);
1896         poh = &pmc_ownerhash[hindex];
1897
1898         /* allocate space for N pointers and one descriptor struct */
1899         po = malloc(sizeof(struct pmc_owner), M_PMC, M_WAITOK|M_ZERO);
1900         po->po_sscount = po->po_error = po->po_flags = 0;
1901         po->po_file  = NULL;
1902         po->po_owner = p;
1903         po->po_kthread = NULL;
1904         LIST_INIT(&po->po_pmcs);
1905         LIST_INSERT_HEAD(poh, po, po_next); /* insert into hash table */
1906
1907         TAILQ_INIT(&po->po_logbuffers);
1908         mtx_init(&po->po_mtx, "pmc-owner-mtx", "pmc-per-proc", MTX_SPIN);
1909
1910         PMCDBG(OWN,ALL,1, "allocate-owner proc=%p (%d, %s) pmc-owner=%p",
1911             p, p->p_pid, p->p_comm, po);
1912
1913         return po;
1914 }
1915
1916 static void
1917 pmc_destroy_owner_descriptor(struct pmc_owner *po)
1918 {
1919
1920         PMCDBG(OWN,REL,1, "destroy-owner po=%p proc=%p (%d, %s)",
1921             po, po->po_owner, po->po_owner->p_pid, po->po_owner->p_comm);
1922
1923         mtx_destroy(&po->po_mtx);
1924         free(po, M_PMC);
1925 }
1926
1927 /*
1928  * find the descriptor corresponding to process 'p', adding or removing it
1929  * as specified by 'mode'.
1930  */
1931
1932 static struct pmc_process *
1933 pmc_find_process_descriptor(struct proc *p, uint32_t mode)
1934 {
1935         uint32_t hindex;
1936         struct pmc_process *pp, *ppnew;
1937         struct pmc_processhash *pph;
1938
1939         hindex = PMC_HASH_PTR(p, pmc_processhashmask);
1940         pph = &pmc_processhash[hindex];
1941
1942         ppnew = NULL;
1943
1944         /*
1945          * Pre-allocate memory in the FIND_ALLOCATE case since we
1946          * cannot call malloc(9) once we hold a spin lock.
1947          */
1948         if (mode & PMC_FLAG_ALLOCATE)
1949                 ppnew = malloc(sizeof(struct pmc_process) + md->pmd_npmc *
1950                     sizeof(struct pmc_targetstate), M_PMC, M_WAITOK|M_ZERO);
1951
1952         mtx_lock_spin(&pmc_processhash_mtx);
1953         LIST_FOREACH(pp, pph, pp_next)
1954             if (pp->pp_proc == p)
1955                     break;
1956
1957         if ((mode & PMC_FLAG_REMOVE) && pp != NULL)
1958                 LIST_REMOVE(pp, pp_next);
1959
1960         if ((mode & PMC_FLAG_ALLOCATE) && pp == NULL &&
1961             ppnew != NULL) {
1962                 ppnew->pp_proc = p;
1963                 LIST_INSERT_HEAD(pph, ppnew, pp_next);
1964                 pp = ppnew;
1965                 ppnew = NULL;
1966         }
1967         mtx_unlock_spin(&pmc_processhash_mtx);
1968
1969         if (pp != NULL && ppnew != NULL)
1970                 free(ppnew, M_PMC);
1971
1972         return pp;
1973 }
1974
1975 /*
1976  * remove a process descriptor from the process hash table.
1977  */
1978
1979 static void
1980 pmc_remove_process_descriptor(struct pmc_process *pp)
1981 {
1982         KASSERT(pp->pp_refcnt == 0,
1983             ("[pmc,%d] Removing process descriptor %p with count %d",
1984                 __LINE__, pp, pp->pp_refcnt));
1985
1986         mtx_lock_spin(&pmc_processhash_mtx);
1987         LIST_REMOVE(pp, pp_next);
1988         mtx_unlock_spin(&pmc_processhash_mtx);
1989 }
1990
1991
1992 /*
1993  * find an owner descriptor corresponding to proc 'p'
1994  */
1995
1996 static struct pmc_owner *
1997 pmc_find_owner_descriptor(struct proc *p)
1998 {
1999         uint32_t hindex;
2000         struct pmc_owner *po;
2001         struct pmc_ownerhash *poh;
2002
2003         hindex = PMC_HASH_PTR(p, pmc_ownerhashmask);
2004         poh = &pmc_ownerhash[hindex];
2005
2006         po = NULL;
2007         LIST_FOREACH(po, poh, po_next)
2008             if (po->po_owner == p)
2009                     break;
2010
2011         PMCDBG(OWN,FND,1, "find-owner proc=%p (%d, %s) hindex=0x%x -> "
2012             "pmc-owner=%p", p, p->p_pid, p->p_comm, hindex, po);
2013
2014         return po;
2015 }
2016
2017 /*
2018  * pmc_allocate_pmc_descriptor
2019  *
2020  * Allocate a pmc descriptor and initialize its
2021  * fields.
2022  */
2023
2024 static struct pmc *
2025 pmc_allocate_pmc_descriptor(void)
2026 {
2027         struct pmc *pmc;
2028
2029         pmc = malloc(sizeof(struct pmc), M_PMC, M_WAITOK|M_ZERO);
2030
2031         if (pmc != NULL) {
2032                 pmc->pm_owner = NULL;
2033                 LIST_INIT(&pmc->pm_targets);
2034         }
2035
2036         PMCDBG(PMC,ALL,1, "allocate-pmc -> pmc=%p", pmc);
2037
2038         return pmc;
2039 }
2040
2041 /*
2042  * Destroy a pmc descriptor.
2043  */
2044
2045 static void
2046 pmc_destroy_pmc_descriptor(struct pmc *pm)
2047 {
2048         (void) pm;
2049
2050 #ifdef  DEBUG
2051         KASSERT(pm->pm_state == PMC_STATE_DELETED ||
2052             pm->pm_state == PMC_STATE_FREE,
2053             ("[pmc,%d] destroying non-deleted PMC", __LINE__));
2054         KASSERT(LIST_EMPTY(&pm->pm_targets),
2055             ("[pmc,%d] destroying pmc with targets", __LINE__));
2056         KASSERT(pm->pm_owner == NULL,
2057             ("[pmc,%d] destroying pmc attached to an owner", __LINE__));
2058         KASSERT(pm->pm_runcount == 0,
2059             ("[pmc,%d] pmc has non-zero run count %d", __LINE__,
2060                 pm->pm_runcount));
2061 #endif
2062 }
2063
2064 static void
2065 pmc_wait_for_pmc_idle(struct pmc *pm)
2066 {
2067 #ifdef  DEBUG
2068         volatile int maxloop;
2069
2070         maxloop = 100 * pmc_cpu_max();
2071 #endif
2072
2073         /*
2074          * Loop (with a forced context switch) till the PMC's runcount
2075          * comes down to zero.
2076          */
2077         while (atomic_load_acq_32(&pm->pm_runcount) > 0) {
2078 #ifdef  DEBUG
2079                 maxloop--;
2080                 KASSERT(maxloop > 0,
2081                     ("[pmc,%d] (ri%d, rc%d) waiting too long for "
2082                         "pmc to be free", __LINE__,
2083                         PMC_TO_ROWINDEX(pm), pm->pm_runcount));
2084 #endif
2085                 pmc_force_context_switch();
2086         }
2087 }
2088
2089 /*
2090  * This function does the following things:
2091  *
2092  *  - detaches the PMC from hardware
2093  *  - unlinks all target threads that were attached to it
2094  *  - removes the PMC from its owner's list
2095  *  - destroy's the PMC private mutex
2096  *
2097  * Once this function completes, the given pmc pointer can be safely
2098  * FREE'd by the caller.
2099  */
2100
2101 static void
2102 pmc_release_pmc_descriptor(struct pmc *pm)
2103 {
2104         enum pmc_mode mode;
2105         struct pmc_hw *phw;
2106         u_int adjri, ri, cpu;
2107         struct pmc_owner *po;
2108         struct pmc_binding pb;
2109         struct pmc_process *pp;
2110         struct pmc_classdep *pcd;
2111         struct pmc_target *ptgt, *tmp;
2112
2113         sx_assert(&pmc_sx, SX_XLOCKED);
2114
2115         KASSERT(pm, ("[pmc,%d] null pmc", __LINE__));
2116
2117         ri   = PMC_TO_ROWINDEX(pm);
2118         pcd  = pmc_ri_to_classdep(md, ri, &adjri);
2119         mode = PMC_TO_MODE(pm);
2120
2121         PMCDBG(PMC,REL,1, "release-pmc pmc=%p ri=%d mode=%d", pm, ri,
2122             mode);
2123
2124         /*
2125          * First, we take the PMC off hardware.
2126          */
2127         cpu = 0;
2128         if (PMC_IS_SYSTEM_MODE(mode)) {
2129
2130                 /*
2131                  * A system mode PMC runs on a specific CPU.  Switch
2132                  * to this CPU and turn hardware off.
2133                  */
2134                 pmc_save_cpu_binding(&pb);
2135
2136                 cpu = PMC_TO_CPU(pm);
2137
2138                 pmc_select_cpu(cpu);
2139
2140                 /* switch off non-stalled CPUs */
2141                 if (pm->pm_state == PMC_STATE_RUNNING &&
2142                     pm->pm_stalled == 0) {
2143
2144                         phw = pmc_pcpu[cpu]->pc_hwpmcs[ri];
2145
2146                         KASSERT(phw->phw_pmc == pm,
2147                             ("[pmc, %d] pmc ptr ri(%d) hw(%p) pm(%p)",
2148                                 __LINE__, ri, phw->phw_pmc, pm));
2149                         PMCDBG(PMC,REL,2, "stopping cpu=%d ri=%d", cpu, ri);
2150
2151                         critical_enter();
2152                         pcd->pcd_stop_pmc(cpu, adjri);
2153                         critical_exit();
2154                 }
2155
2156                 PMCDBG(PMC,REL,2, "decfg cpu=%d ri=%d", cpu, ri);
2157
2158                 critical_enter();
2159                 pcd->pcd_config_pmc(cpu, adjri, NULL);
2160                 critical_exit();
2161
2162                 /* adjust the global and process count of SS mode PMCs */
2163                 if (mode == PMC_MODE_SS && pm->pm_state == PMC_STATE_RUNNING) {
2164                         po = pm->pm_owner;
2165                         po->po_sscount--;
2166                         if (po->po_sscount == 0) {
2167                                 atomic_subtract_rel_int(&pmc_ss_count, 1);
2168                                 LIST_REMOVE(po, po_ssnext);
2169                         }
2170                 }
2171
2172                 pm->pm_state = PMC_STATE_DELETED;
2173
2174                 pmc_restore_cpu_binding(&pb);
2175
2176                 /*
2177                  * We could have references to this PMC structure in
2178                  * the per-cpu sample queues.  Wait for the queue to
2179                  * drain.
2180                  */
2181                 pmc_wait_for_pmc_idle(pm);
2182
2183         } else if (PMC_IS_VIRTUAL_MODE(mode)) {
2184
2185                 /*
2186                  * A virtual PMC could be running on multiple CPUs at
2187                  * a given instant.
2188                  *
2189                  * By marking its state as DELETED, we ensure that
2190                  * this PMC is never further scheduled on hardware.
2191                  *
2192                  * Then we wait till all CPUs are done with this PMC.
2193                  */
2194                 pm->pm_state = PMC_STATE_DELETED;
2195
2196
2197                 /* Wait for the PMCs runcount to come to zero. */
2198                 pmc_wait_for_pmc_idle(pm);
2199
2200                 /*
2201                  * At this point the PMC is off all CPUs and cannot be
2202                  * freshly scheduled onto a CPU.  It is now safe to
2203                  * unlink all targets from this PMC.  If a
2204                  * process-record's refcount falls to zero, we remove
2205                  * it from the hash table.  The module-wide SX lock
2206                  * protects us from races.
2207                  */
2208                 LIST_FOREACH_SAFE(ptgt, &pm->pm_targets, pt_next, tmp) {
2209                         pp = ptgt->pt_process;
2210                         pmc_unlink_target_process(pm, pp); /* frees 'ptgt' */
2211
2212                         PMCDBG(PMC,REL,3, "pp->refcnt=%d", pp->pp_refcnt);
2213
2214                         /*
2215                          * If the target process record shows that no
2216                          * PMCs are attached to it, reclaim its space.
2217                          */
2218
2219                         if (pp->pp_refcnt == 0) {
2220                                 pmc_remove_process_descriptor(pp);
2221                                 free(pp, M_PMC);
2222                         }
2223                 }
2224
2225                 cpu = curthread->td_oncpu; /* setup cpu for pmd_release() */
2226
2227         }
2228
2229         /*
2230          * Release any MD resources
2231          */
2232         (void) pcd->pcd_release_pmc(cpu, adjri, pm);
2233
2234         /*
2235          * Update row disposition
2236          */
2237
2238         if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm)))
2239                 PMC_UNMARK_ROW_STANDALONE(ri);
2240         else
2241                 PMC_UNMARK_ROW_THREAD(ri);
2242
2243         /* unlink from the owner's list */
2244         if (pm->pm_owner) {
2245                 LIST_REMOVE(pm, pm_next);
2246                 pm->pm_owner = NULL;
2247         }
2248
2249         pmc_destroy_pmc_descriptor(pm);
2250 }
2251
2252 /*
2253  * Register an owner and a pmc.
2254  */
2255
2256 static int
2257 pmc_register_owner(struct proc *p, struct pmc *pmc)
2258 {
2259         struct pmc_owner *po;
2260
2261         sx_assert(&pmc_sx, SX_XLOCKED);
2262
2263         if ((po = pmc_find_owner_descriptor(p)) == NULL)
2264                 if ((po = pmc_allocate_owner_descriptor(p)) == NULL)
2265                         return ENOMEM;
2266
2267         KASSERT(pmc->pm_owner == NULL,
2268             ("[pmc,%d] attempting to own an initialized PMC", __LINE__));
2269         pmc->pm_owner  = po;
2270
2271         LIST_INSERT_HEAD(&po->po_pmcs, pmc, pm_next);
2272
2273         PROC_LOCK(p);
2274         p->p_flag |= P_HWPMC;
2275         PROC_UNLOCK(p);
2276
2277         if (po->po_flags & PMC_PO_OWNS_LOGFILE)
2278                 pmclog_process_pmcallocate(pmc);
2279
2280         PMCDBG(PMC,REG,1, "register-owner pmc-owner=%p pmc=%p",
2281             po, pmc);
2282
2283         return 0;
2284 }
2285
2286 /*
2287  * Return the current row disposition:
2288  * == 0 => FREE
2289  *  > 0 => PROCESS MODE
2290  *  < 0 => SYSTEM MODE
2291  */
2292
2293 int
2294 pmc_getrowdisp(int ri)
2295 {
2296         return pmc_pmcdisp[ri];
2297 }
2298
2299 /*
2300  * Check if a PMC at row index 'ri' can be allocated to the current
2301  * process.
2302  *
2303  * Allocation can fail if:
2304  *   - the current process is already being profiled by a PMC at index 'ri',
2305  *     attached to it via OP_PMCATTACH.
2306  *   - the current process has already allocated a PMC at index 'ri'
2307  *     via OP_ALLOCATE.
2308  */
2309
2310 static int
2311 pmc_can_allocate_rowindex(struct proc *p, unsigned int ri, int cpu)
2312 {
2313         enum pmc_mode mode;
2314         struct pmc *pm;
2315         struct pmc_owner *po;
2316         struct pmc_process *pp;
2317
2318         PMCDBG(PMC,ALR,1, "can-allocate-rowindex proc=%p (%d, %s) ri=%d "
2319             "cpu=%d", p, p->p_pid, p->p_comm, ri, cpu);
2320
2321         /*
2322          * We shouldn't have already allocated a process-mode PMC at
2323          * row index 'ri'.
2324          *
2325          * We shouldn't have allocated a system-wide PMC on the same
2326          * CPU and same RI.
2327          */
2328         if ((po = pmc_find_owner_descriptor(p)) != NULL)
2329                 LIST_FOREACH(pm, &po->po_pmcs, pm_next) {
2330                     if (PMC_TO_ROWINDEX(pm) == ri) {
2331                             mode = PMC_TO_MODE(pm);
2332                             if (PMC_IS_VIRTUAL_MODE(mode))
2333                                     return EEXIST;
2334                             if (PMC_IS_SYSTEM_MODE(mode) &&
2335                                 (int) PMC_TO_CPU(pm) == cpu)
2336                                     return EEXIST;
2337                     }
2338                 }
2339
2340         /*
2341          * We also shouldn't be the target of any PMC at this index
2342          * since otherwise a PMC_ATTACH to ourselves will fail.
2343          */
2344         if ((pp = pmc_find_process_descriptor(p, 0)) != NULL)
2345                 if (pp->pp_pmcs[ri].pp_pmc)
2346                         return EEXIST;
2347
2348         PMCDBG(PMC,ALR,2, "can-allocate-rowindex proc=%p (%d, %s) ri=%d ok",
2349             p, p->p_pid, p->p_comm, ri);
2350
2351         return 0;
2352 }
2353
2354 /*
2355  * Check if a given PMC at row index 'ri' can be currently used in
2356  * mode 'mode'.
2357  */
2358
2359 static int
2360 pmc_can_allocate_row(int ri, enum pmc_mode mode)
2361 {
2362         enum pmc_disp   disp;
2363
2364         sx_assert(&pmc_sx, SX_XLOCKED);
2365
2366         PMCDBG(PMC,ALR,1, "can-allocate-row ri=%d mode=%d", ri, mode);
2367
2368         if (PMC_IS_SYSTEM_MODE(mode))
2369                 disp = PMC_DISP_STANDALONE;
2370         else
2371                 disp = PMC_DISP_THREAD;
2372
2373         /*
2374          * check disposition for PMC row 'ri':
2375          *
2376          * Expected disposition         Row-disposition         Result
2377          *
2378          * STANDALONE                   STANDALONE or FREE      proceed
2379          * STANDALONE                   THREAD                  fail
2380          * THREAD                       THREAD or FREE          proceed
2381          * THREAD                       STANDALONE              fail
2382          */
2383
2384         if (!PMC_ROW_DISP_IS_FREE(ri) &&
2385             !(disp == PMC_DISP_THREAD && PMC_ROW_DISP_IS_THREAD(ri)) &&
2386             !(disp == PMC_DISP_STANDALONE && PMC_ROW_DISP_IS_STANDALONE(ri)))
2387                 return EBUSY;
2388
2389         /*
2390          * All OK
2391          */
2392
2393         PMCDBG(PMC,ALR,2, "can-allocate-row ri=%d mode=%d ok", ri, mode);
2394
2395         return 0;
2396
2397 }
2398
2399 /*
2400  * Find a PMC descriptor with user handle 'pmcid' for thread 'td'.
2401  */
2402
2403 static struct pmc *
2404 pmc_find_pmc_descriptor_in_process(struct pmc_owner *po, pmc_id_t pmcid)
2405 {
2406         struct pmc *pm;
2407
2408         KASSERT(PMC_ID_TO_ROWINDEX(pmcid) < md->pmd_npmc,
2409             ("[pmc,%d] Illegal pmc index %d (max %d)", __LINE__,
2410                 PMC_ID_TO_ROWINDEX(pmcid), md->pmd_npmc));
2411
2412         LIST_FOREACH(pm, &po->po_pmcs, pm_next)
2413             if (pm->pm_id == pmcid)
2414                     return pm;
2415
2416         return NULL;
2417 }
2418
2419 static int
2420 pmc_find_pmc(pmc_id_t pmcid, struct pmc **pmc)
2421 {
2422
2423         struct pmc *pm;
2424         struct pmc_owner *po;
2425
2426         PMCDBG(PMC,FND,1, "find-pmc id=%d", pmcid);
2427
2428         if ((po = pmc_find_owner_descriptor(curthread->td_proc)) == NULL)
2429                 return ESRCH;
2430
2431         if ((pm = pmc_find_pmc_descriptor_in_process(po, pmcid)) == NULL)
2432                 return EINVAL;
2433
2434         PMCDBG(PMC,FND,2, "find-pmc id=%d -> pmc=%p", pmcid, pm);
2435
2436         *pmc = pm;
2437         return 0;
2438 }
2439
2440 /*
2441  * Start a PMC.
2442  */
2443
2444 static int
2445 pmc_start(struct pmc *pm)
2446 {
2447         enum pmc_mode mode;
2448         struct pmc_owner *po;
2449         struct pmc_binding pb;
2450         struct pmc_classdep *pcd;
2451         int adjri, error, cpu, ri;
2452
2453         KASSERT(pm != NULL,
2454             ("[pmc,%d] null pm", __LINE__));
2455
2456         mode = PMC_TO_MODE(pm);
2457         ri   = PMC_TO_ROWINDEX(pm);
2458         pcd  = pmc_ri_to_classdep(md, ri, &adjri);
2459
2460         error = 0;
2461
2462         PMCDBG(PMC,OPS,1, "start pmc=%p mode=%d ri=%d", pm, mode, ri);
2463
2464         po = pm->pm_owner;
2465
2466         /*
2467          * Disallow PMCSTART if a logfile is required but has not been
2468          * configured yet.
2469          */
2470         if ((pm->pm_flags & PMC_F_NEEDS_LOGFILE) &&
2471             (po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)
2472                 return (EDOOFUS);       /* programming error */
2473
2474         /*
2475          * If this is a sampling mode PMC, log mapping information for
2476          * the kernel modules that are currently loaded.
2477          */
2478         if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
2479             pmc_log_kernel_mappings(pm);
2480
2481         if (PMC_IS_VIRTUAL_MODE(mode)) {
2482
2483                 /*
2484                  * If a PMCATTACH has never been done on this PMC,
2485                  * attach it to its owner process.
2486                  */
2487
2488                 if (LIST_EMPTY(&pm->pm_targets))
2489                         error = (pm->pm_flags & PMC_F_ATTACH_DONE) ? ESRCH :
2490                             pmc_attach_process(po->po_owner, pm);
2491
2492                 /*
2493                  * If the PMC is attached to its owner, then force a context
2494                  * switch to ensure that the MD state gets set correctly.
2495                  */
2496
2497                 if (error == 0) {
2498                         pm->pm_state = PMC_STATE_RUNNING;
2499                         if (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER)
2500                                 pmc_force_context_switch();
2501                 }
2502
2503                 return (error);
2504         }
2505
2506
2507         /*
2508          * A system-wide PMC.
2509          *
2510          * Add the owner to the global list if this is a system-wide
2511          * sampling PMC.
2512          */
2513
2514         if (mode == PMC_MODE_SS) {
2515                 if (po->po_sscount == 0) {
2516                         LIST_INSERT_HEAD(&pmc_ss_owners, po, po_ssnext);
2517                         atomic_add_rel_int(&pmc_ss_count, 1);
2518                         PMCDBG(PMC,OPS,1, "po=%p in global list", po);
2519                 }
2520                 po->po_sscount++;
2521         }
2522
2523         /* Log mapping information for all processes in the system. */
2524         pmc_log_all_process_mappings(po);
2525
2526         /*
2527          * Move to the CPU associated with this
2528          * PMC, and start the hardware.
2529          */
2530
2531         pmc_save_cpu_binding(&pb);
2532
2533         cpu = PMC_TO_CPU(pm);
2534
2535         if (!pmc_cpu_is_active(cpu))
2536                 return (ENXIO);
2537
2538         pmc_select_cpu(cpu);
2539
2540         /*
2541          * global PMCs are configured at allocation time
2542          * so write out the initial value and start the PMC.
2543          */
2544
2545         pm->pm_state = PMC_STATE_RUNNING;
2546
2547         critical_enter();
2548         if ((error = pcd->pcd_write_pmc(cpu, adjri,
2549                  PMC_IS_SAMPLING_MODE(mode) ?
2550                  pm->pm_sc.pm_reloadcount :
2551                  pm->pm_sc.pm_initial)) == 0)
2552                 error = pcd->pcd_start_pmc(cpu, adjri);
2553         critical_exit();
2554
2555         pmc_restore_cpu_binding(&pb);
2556
2557         return (error);
2558 }
2559
2560 /*
2561  * Stop a PMC.
2562  */
2563
2564 static int
2565 pmc_stop(struct pmc *pm)
2566 {
2567         struct pmc_owner *po;
2568         struct pmc_binding pb;
2569         struct pmc_classdep *pcd;
2570         int adjri, cpu, error, ri;
2571
2572         KASSERT(pm != NULL, ("[pmc,%d] null pmc", __LINE__));
2573
2574         PMCDBG(PMC,OPS,1, "stop pmc=%p mode=%d ri=%d", pm,
2575             PMC_TO_MODE(pm), PMC_TO_ROWINDEX(pm));
2576
2577         pm->pm_state = PMC_STATE_STOPPED;
2578
2579         /*
2580          * If the PMC is a virtual mode one, changing the state to
2581          * non-RUNNING is enough to ensure that the PMC never gets
2582          * scheduled.
2583          *
2584          * If this PMC is current running on a CPU, then it will
2585          * handled correctly at the time its target process is context
2586          * switched out.
2587          */
2588
2589         if (PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)))
2590                 return 0;
2591
2592         /*
2593          * A system-mode PMC.  Move to the CPU associated with
2594          * this PMC, and stop the hardware.  We update the
2595          * 'initial count' so that a subsequent PMCSTART will
2596          * resume counting from the current hardware count.
2597          */
2598
2599         pmc_save_cpu_binding(&pb);
2600
2601         cpu = PMC_TO_CPU(pm);
2602
2603         KASSERT(cpu >= 0 && cpu < pmc_cpu_max(),
2604             ("[pmc,%d] illegal cpu=%d", __LINE__, cpu));
2605
2606         if (!pmc_cpu_is_active(cpu))
2607                 return ENXIO;
2608
2609         pmc_select_cpu(cpu);
2610
2611         ri = PMC_TO_ROWINDEX(pm);
2612         pcd = pmc_ri_to_classdep(md, ri, &adjri);
2613
2614         critical_enter();
2615         if ((error = pcd->pcd_stop_pmc(cpu, adjri)) == 0)
2616                 error = pcd->pcd_read_pmc(cpu, adjri, &pm->pm_sc.pm_initial);
2617         critical_exit();
2618
2619         pmc_restore_cpu_binding(&pb);
2620
2621         po = pm->pm_owner;
2622
2623         /* remove this owner from the global list of SS PMC owners */
2624         if (PMC_TO_MODE(pm) == PMC_MODE_SS) {
2625                 po->po_sscount--;
2626                 if (po->po_sscount == 0) {
2627                         atomic_subtract_rel_int(&pmc_ss_count, 1);
2628                         LIST_REMOVE(po, po_ssnext);
2629                         PMCDBG(PMC,OPS,2,"po=%p removed from global list", po);
2630                 }
2631         }
2632
2633         return (error);
2634 }
2635
2636
2637 #ifdef  DEBUG
2638 static const char *pmc_op_to_name[] = {
2639 #undef  __PMC_OP
2640 #define __PMC_OP(N, D)  #N ,
2641         __PMC_OPS()
2642         NULL
2643 };
2644 #endif
2645
2646 /*
2647  * The syscall interface
2648  */
2649
2650 #define PMC_GET_SX_XLOCK(...) do {              \
2651         sx_xlock(&pmc_sx);                      \
2652         if (pmc_hook == NULL) {                 \
2653                 sx_xunlock(&pmc_sx);            \
2654                 return __VA_ARGS__;             \
2655         }                                       \
2656 } while (0)
2657
2658 #define PMC_DOWNGRADE_SX() do {                 \
2659         sx_downgrade(&pmc_sx);                  \
2660         is_sx_downgraded = 1;                   \
2661 } while (0)
2662
2663 static int
2664 pmc_syscall_handler(struct thread *td, void *syscall_args)
2665 {
2666         int error, is_sx_downgraded, is_sx_locked, op;
2667         struct pmc_syscall_args *c;
2668         void *arg;
2669
2670         PMC_GET_SX_XLOCK(ENOSYS);
2671
2672         DROP_GIANT();
2673
2674         is_sx_downgraded = 0;
2675         is_sx_locked = 1;
2676
2677         c = (struct pmc_syscall_args *) syscall_args;
2678
2679         op = c->pmop_code;
2680         arg = c->pmop_data;
2681
2682         PMCDBG(MOD,PMS,1, "syscall op=%d \"%s\" arg=%p", op,
2683             pmc_op_to_name[op], arg);
2684
2685         error = 0;
2686         atomic_add_int(&pmc_stats.pm_syscalls, 1);
2687
2688         switch(op)
2689         {
2690
2691
2692         /*
2693          * Configure a log file.
2694          *
2695          * XXX This OP will be reworked.
2696          */
2697
2698         case PMC_OP_CONFIGURELOG:
2699         {
2700                 struct proc *p;
2701                 struct pmc *pm;
2702                 struct pmc_owner *po;
2703                 struct pmc_op_configurelog cl;
2704
2705                 sx_assert(&pmc_sx, SX_XLOCKED);
2706
2707                 if ((error = copyin(arg, &cl, sizeof(cl))) != 0)
2708                         break;
2709
2710                 /* mark this process as owning a log file */
2711                 p = td->td_proc;
2712                 if ((po = pmc_find_owner_descriptor(p)) == NULL)
2713                         if ((po = pmc_allocate_owner_descriptor(p)) == NULL) {
2714                                 error = ENOMEM;
2715                                 break;
2716                         }
2717
2718                 /*
2719                  * If a valid fd was passed in, try to configure that,
2720                  * otherwise if 'fd' was less than zero and there was
2721                  * a log file configured, flush its buffers and
2722                  * de-configure it.
2723                  */
2724                 if (cl.pm_logfd >= 0) {
2725                         sx_xunlock(&pmc_sx);
2726                         is_sx_locked = 0;
2727                         error = pmclog_configure_log(md, po, cl.pm_logfd);
2728                 } else if (po->po_flags & PMC_PO_OWNS_LOGFILE) {
2729                         pmclog_process_closelog(po);
2730                         error = pmclog_flush(po);
2731                         if (error == 0) {
2732                                 LIST_FOREACH(pm, &po->po_pmcs, pm_next)
2733                                     if (pm->pm_flags & PMC_F_NEEDS_LOGFILE &&
2734                                         pm->pm_state == PMC_STATE_RUNNING)
2735                                             pmc_stop(pm);
2736                                 error = pmclog_deconfigure_log(po);
2737                         }
2738                 } else
2739                         error = EINVAL;
2740
2741                 if (error)
2742                         break;
2743         }
2744         break;
2745
2746
2747         /*
2748          * Flush a log file.
2749          */
2750
2751         case PMC_OP_FLUSHLOG:
2752         {
2753                 struct pmc_owner *po;
2754
2755                 sx_assert(&pmc_sx, SX_XLOCKED);
2756
2757                 if ((po = pmc_find_owner_descriptor(td->td_proc)) == NULL) {
2758                         error = EINVAL;
2759                         break;
2760                 }
2761
2762                 error = pmclog_flush(po);
2763         }
2764         break;
2765
2766         /*
2767          * Retrieve hardware configuration.
2768          */
2769
2770         case PMC_OP_GETCPUINFO: /* CPU information */
2771         {
2772                 struct pmc_op_getcpuinfo gci;
2773                 struct pmc_classinfo *pci;
2774                 struct pmc_classdep *pcd;
2775                 int cl;
2776
2777                 gci.pm_cputype = md->pmd_cputype;
2778                 gci.pm_ncpu    = pmc_cpu_max();
2779                 gci.pm_npmc    = md->pmd_npmc;
2780                 gci.pm_nclass  = md->pmd_nclass;
2781                 pci = gci.pm_classes;
2782                 pcd = md->pmd_classdep;
2783                 for (cl = 0; cl < md->pmd_nclass; cl++, pci++, pcd++) {
2784                         pci->pm_caps  = pcd->pcd_caps;
2785                         pci->pm_class = pcd->pcd_class;
2786                         pci->pm_width = pcd->pcd_width;
2787                         pci->pm_num   = pcd->pcd_num;
2788                 }
2789                 error = copyout(&gci, arg, sizeof(gci));
2790         }
2791         break;
2792
2793
2794         /*
2795          * Get module statistics
2796          */
2797
2798         case PMC_OP_GETDRIVERSTATS:
2799         {
2800                 struct pmc_op_getdriverstats gms;
2801
2802                 bcopy(&pmc_stats, &gms, sizeof(gms));
2803                 error = copyout(&gms, arg, sizeof(gms));
2804         }
2805         break;
2806
2807
2808         /*
2809          * Retrieve module version number
2810          */
2811
2812         case PMC_OP_GETMODULEVERSION:
2813         {
2814                 uint32_t cv, modv;
2815
2816                 /* retrieve the client's idea of the ABI version */
2817                 if ((error = copyin(arg, &cv, sizeof(uint32_t))) != 0)
2818                         break;
2819                 /* don't service clients newer than our driver */
2820                 modv = PMC_VERSION;
2821                 if ((cv & 0xFFFF0000) > (modv & 0xFFFF0000)) {
2822                         error = EPROGMISMATCH;
2823                         break;
2824                 }
2825                 error = copyout(&modv, arg, sizeof(int));
2826         }
2827         break;
2828
2829
2830         /*
2831          * Retrieve the state of all the PMCs on a given
2832          * CPU.
2833          */
2834
2835         case PMC_OP_GETPMCINFO:
2836         {
2837                 int ari;
2838                 struct pmc *pm;
2839                 size_t pmcinfo_size;
2840                 uint32_t cpu, n, npmc;
2841                 struct pmc_owner *po;
2842                 struct pmc_binding pb;
2843                 struct pmc_classdep *pcd;
2844                 struct pmc_info *p, *pmcinfo;
2845                 struct pmc_op_getpmcinfo *gpi;
2846
2847                 PMC_DOWNGRADE_SX();
2848
2849                 gpi = (struct pmc_op_getpmcinfo *) arg;
2850
2851                 if ((error = copyin(&gpi->pm_cpu, &cpu, sizeof(cpu))) != 0)
2852                         break;
2853
2854                 if (cpu >= pmc_cpu_max()) {
2855                         error = EINVAL;
2856                         break;
2857                 }
2858
2859                 if (!pmc_cpu_is_active(cpu)) {
2860                         error = ENXIO;
2861                         break;
2862                 }
2863
2864                 /* switch to CPU 'cpu' */
2865                 pmc_save_cpu_binding(&pb);
2866                 pmc_select_cpu(cpu);
2867
2868                 npmc = md->pmd_npmc;
2869
2870                 pmcinfo_size = npmc * sizeof(struct pmc_info);
2871                 pmcinfo = malloc(pmcinfo_size, M_PMC, M_WAITOK);
2872
2873                 p = pmcinfo;
2874
2875                 for (n = 0; n < md->pmd_npmc; n++, p++) {
2876
2877                         pcd = pmc_ri_to_classdep(md, n, &ari);
2878
2879                         KASSERT(pcd != NULL,
2880                             ("[pmc,%d] null pcd ri=%d", __LINE__, n));
2881
2882                         if ((error = pcd->pcd_describe(cpu, ari, p, &pm)) != 0)
2883                                 break;
2884
2885                         if (PMC_ROW_DISP_IS_STANDALONE(n))
2886                                 p->pm_rowdisp = PMC_DISP_STANDALONE;
2887                         else if (PMC_ROW_DISP_IS_THREAD(n))
2888                                 p->pm_rowdisp = PMC_DISP_THREAD;
2889                         else
2890                                 p->pm_rowdisp = PMC_DISP_FREE;
2891
2892                         p->pm_ownerpid = -1;
2893
2894                         if (pm == NULL) /* no PMC associated */
2895                                 continue;
2896
2897                         po = pm->pm_owner;
2898
2899                         KASSERT(po->po_owner != NULL,
2900                             ("[pmc,%d] pmc_owner had a null proc pointer",
2901                                 __LINE__));
2902
2903                         p->pm_ownerpid = po->po_owner->p_pid;
2904                         p->pm_mode     = PMC_TO_MODE(pm);
2905                         p->pm_event    = pm->pm_event;
2906                         p->pm_flags    = pm->pm_flags;
2907
2908                         if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
2909                                 p->pm_reloadcount =
2910                                     pm->pm_sc.pm_reloadcount;
2911                 }
2912
2913                 pmc_restore_cpu_binding(&pb);
2914
2915                 /* now copy out the PMC info collected */
2916                 if (error == 0)
2917                         error = copyout(pmcinfo, &gpi->pm_pmcs, pmcinfo_size);
2918
2919                 free(pmcinfo, M_PMC);
2920         }
2921         break;
2922
2923
2924         /*
2925          * Set the administrative state of a PMC.  I.e. whether
2926          * the PMC is to be used or not.
2927          */
2928
2929         case PMC_OP_PMCADMIN:
2930         {
2931                 int cpu, ri;
2932                 enum pmc_state request;
2933                 struct pmc_cpu *pc;
2934                 struct pmc_hw *phw;
2935                 struct pmc_op_pmcadmin pma;
2936                 struct pmc_binding pb;
2937
2938                 sx_assert(&pmc_sx, SX_XLOCKED);
2939
2940                 KASSERT(td == curthread,
2941                     ("[pmc,%d] td != curthread", __LINE__));
2942
2943                 error = priv_check(td, PRIV_PMC_MANAGE);
2944                 if (error)
2945                         break;
2946
2947                 if ((error = copyin(arg, &pma, sizeof(pma))) != 0)
2948                         break;
2949
2950                 cpu = pma.pm_cpu;
2951
2952                 if (cpu < 0 || cpu >= (int) pmc_cpu_max()) {
2953                         error = EINVAL;
2954                         break;
2955                 }
2956
2957                 if (!pmc_cpu_is_active(cpu)) {
2958                         error = ENXIO;
2959                         break;
2960                 }
2961
2962                 request = pma.pm_state;
2963
2964                 if (request != PMC_STATE_DISABLED &&
2965                     request != PMC_STATE_FREE) {
2966                         error = EINVAL;
2967                         break;
2968                 }
2969
2970                 ri = pma.pm_pmc; /* pmc id == row index */
2971                 if (ri < 0 || ri >= (int) md->pmd_npmc) {
2972                         error = EINVAL;
2973                         break;
2974                 }
2975
2976                 /*
2977                  * We can't disable a PMC with a row-index allocated
2978                  * for process virtual PMCs.
2979                  */
2980
2981                 if (PMC_ROW_DISP_IS_THREAD(ri) &&
2982                     request == PMC_STATE_DISABLED) {
2983                         error = EBUSY;
2984                         break;
2985                 }
2986
2987                 /*
2988                  * otherwise, this PMC on this CPU is either free or
2989                  * in system-wide mode.
2990                  */
2991
2992                 pmc_save_cpu_binding(&pb);
2993                 pmc_select_cpu(cpu);
2994
2995                 pc  = pmc_pcpu[cpu];
2996                 phw = pc->pc_hwpmcs[ri];
2997
2998                 /*
2999                  * XXX do we need some kind of 'forced' disable?
3000                  */
3001
3002                 if (phw->phw_pmc == NULL) {
3003                         if (request == PMC_STATE_DISABLED &&
3004                             (phw->phw_state & PMC_PHW_FLAG_IS_ENABLED)) {
3005                                 phw->phw_state &= ~PMC_PHW_FLAG_IS_ENABLED;
3006                                 PMC_MARK_ROW_STANDALONE(ri);
3007                         } else if (request == PMC_STATE_FREE &&
3008                             (phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) == 0) {
3009                                 phw->phw_state |=  PMC_PHW_FLAG_IS_ENABLED;
3010                                 PMC_UNMARK_ROW_STANDALONE(ri);
3011                         }
3012                         /* other cases are a no-op */
3013                 } else
3014                         error = EBUSY;
3015
3016                 pmc_restore_cpu_binding(&pb);
3017         }
3018         break;
3019
3020
3021         /*
3022          * Allocate a PMC.
3023          */
3024
3025         case PMC_OP_PMCALLOCATE:
3026         {
3027                 int adjri, n;
3028                 u_int cpu;
3029                 uint32_t caps;
3030                 struct pmc *pmc;
3031                 enum pmc_mode mode;
3032                 struct pmc_hw *phw;
3033                 struct pmc_binding pb;
3034                 struct pmc_classdep *pcd;
3035                 struct pmc_op_pmcallocate pa;
3036
3037                 if ((error = copyin(arg, &pa, sizeof(pa))) != 0)
3038                         break;
3039
3040                 caps = pa.pm_caps;
3041                 mode = pa.pm_mode;
3042                 cpu  = pa.pm_cpu;
3043
3044                 if ((mode != PMC_MODE_SS  &&  mode != PMC_MODE_SC  &&
3045                      mode != PMC_MODE_TS  &&  mode != PMC_MODE_TC) ||
3046                     (cpu != (u_int) PMC_CPU_ANY && cpu >= pmc_cpu_max())) {
3047                         error = EINVAL;
3048                         break;
3049                 }
3050
3051                 /*
3052                  * Virtual PMCs should only ask for a default CPU.
3053                  * System mode PMCs need to specify a non-default CPU.
3054                  */
3055
3056                 if ((PMC_IS_VIRTUAL_MODE(mode) && cpu != (u_int) PMC_CPU_ANY) ||
3057                     (PMC_IS_SYSTEM_MODE(mode) && cpu == (u_int) PMC_CPU_ANY)) {
3058                         error = EINVAL;
3059                         break;
3060                 }
3061
3062                 /*
3063                  * Check that an inactive CPU is not being asked for.
3064                  */
3065
3066                 if (PMC_IS_SYSTEM_MODE(mode) && !pmc_cpu_is_active(cpu)) {
3067                         error = ENXIO;
3068                         break;
3069                 }
3070
3071                 /*
3072                  * Refuse an allocation for a system-wide PMC if this
3073                  * process has been jailed, or if this process lacks
3074                  * super-user credentials and the sysctl tunable
3075                  * 'security.bsd.unprivileged_syspmcs' is zero.
3076                  */
3077
3078                 if (PMC_IS_SYSTEM_MODE(mode)) {
3079                         if (jailed(curthread->td_ucred)) {
3080                                 error = EPERM;
3081                                 break;
3082                         }
3083                         if (!pmc_unprivileged_syspmcs) {
3084                                 error = priv_check(curthread,
3085                                     PRIV_PMC_SYSTEM);
3086                                 if (error)
3087                                         break;
3088                         }
3089                 }
3090
3091                 if (error)
3092                         break;
3093
3094                 /*
3095                  * Look for valid values for 'pm_flags'
3096                  */
3097
3098                 if ((pa.pm_flags & ~(PMC_F_DESCENDANTS | PMC_F_LOG_PROCCSW |
3099                     PMC_F_LOG_PROCEXIT | PMC_F_CALLCHAIN)) != 0) {
3100                         error = EINVAL;
3101                         break;
3102                 }
3103
3104                 /* process logging options are not allowed for system PMCs */
3105                 if (PMC_IS_SYSTEM_MODE(mode) && (pa.pm_flags &
3106                     (PMC_F_LOG_PROCCSW | PMC_F_LOG_PROCEXIT))) {
3107                         error = EINVAL;
3108                         break;
3109                 }
3110
3111                 /*
3112                  * All sampling mode PMCs need to be able to interrupt the
3113                  * CPU.
3114                  */
3115                 if (PMC_IS_SAMPLING_MODE(mode))
3116                         caps |= PMC_CAP_INTERRUPT;
3117
3118                 /* A valid class specifier should have been passed in. */
3119                 for (n = 0; n < md->pmd_nclass; n++)
3120                         if (md->pmd_classdep[n].pcd_class == pa.pm_class)
3121                                 break;
3122                 if (n == md->pmd_nclass) {
3123                         error = EINVAL;
3124                         break;
3125                 }
3126
3127                 /* The requested PMC capabilities should be feasible. */
3128                 if ((md->pmd_classdep[n].pcd_caps & caps) != caps) {
3129                         error = EOPNOTSUPP;
3130                         break;
3131                 }
3132
3133                 PMCDBG(PMC,ALL,2, "event=%d caps=0x%x mode=%d cpu=%d",
3134                     pa.pm_ev, caps, mode, cpu);
3135
3136                 pmc = pmc_allocate_pmc_descriptor();
3137                 pmc->pm_id    = PMC_ID_MAKE_ID(cpu,pa.pm_mode,pa.pm_class,
3138                     PMC_ID_INVALID);
3139                 pmc->pm_event = pa.pm_ev;
3140                 pmc->pm_state = PMC_STATE_FREE;
3141                 pmc->pm_caps  = caps;
3142                 pmc->pm_flags = pa.pm_flags;
3143
3144                 /* switch thread to CPU 'cpu' */
3145                 pmc_save_cpu_binding(&pb);
3146
3147 #define PMC_IS_SHAREABLE_PMC(cpu, n)                            \
3148         (pmc_pcpu[(cpu)]->pc_hwpmcs[(n)]->phw_state &           \
3149          PMC_PHW_FLAG_IS_SHAREABLE)
3150 #define PMC_IS_UNALLOCATED(cpu, n)                              \
3151         (pmc_pcpu[(cpu)]->pc_hwpmcs[(n)]->phw_pmc == NULL)
3152
3153                 if (PMC_IS_SYSTEM_MODE(mode)) {
3154                         pmc_select_cpu(cpu);
3155                         for (n = 0; n < (int) md->pmd_npmc; n++) {
3156                                 pcd = pmc_ri_to_classdep(md, n, &adjri);
3157                                 if (pmc_can_allocate_row(n, mode) == 0 &&
3158                                     pmc_can_allocate_rowindex(
3159                                             curthread->td_proc, n, cpu) == 0 &&
3160                                     (PMC_IS_UNALLOCATED(cpu, n) ||
3161                                      PMC_IS_SHAREABLE_PMC(cpu, n)) &&
3162                                     pcd->pcd_allocate_pmc(cpu, adjri, pmc,
3163                                         &pa) == 0)
3164                                         break;
3165                         }
3166                 } else {
3167                         /* Process virtual mode */
3168                         for (n = 0; n < (int) md->pmd_npmc; n++) {
3169                                 pcd = pmc_ri_to_classdep(md, n, &adjri);
3170                                 if (pmc_can_allocate_row(n, mode) == 0 &&
3171                                     pmc_can_allocate_rowindex(
3172                                             curthread->td_proc, n,
3173                                             PMC_CPU_ANY) == 0 &&
3174                                     pcd->pcd_allocate_pmc(curthread->td_oncpu,
3175                                         adjri, pmc, &pa) == 0)
3176                                         break;
3177                         }
3178                 }
3179
3180 #undef  PMC_IS_UNALLOCATED
3181 #undef  PMC_IS_SHAREABLE_PMC
3182
3183                 pmc_restore_cpu_binding(&pb);
3184
3185                 if (n == (int) md->pmd_npmc) {
3186                         pmc_destroy_pmc_descriptor(pmc);
3187                         free(pmc, M_PMC);
3188                         pmc = NULL;
3189                         error = EINVAL;
3190                         break;
3191                 }
3192
3193                 /* Fill in the correct value in the ID field */
3194                 pmc->pm_id = PMC_ID_MAKE_ID(cpu,mode,pa.pm_class,n);
3195
3196                 PMCDBG(PMC,ALL,2, "ev=%d class=%d mode=%d n=%d -> pmcid=%x",
3197                     pmc->pm_event, pa.pm_class, mode, n, pmc->pm_id);
3198
3199                 /* Process mode PMCs with logging enabled need log files */
3200                 if (pmc->pm_flags & (PMC_F_LOG_PROCEXIT | PMC_F_LOG_PROCCSW))
3201                         pmc->pm_flags |= PMC_F_NEEDS_LOGFILE;
3202
3203                 /* All system mode sampling PMCs require a log file */
3204                 if (PMC_IS_SAMPLING_MODE(mode) && PMC_IS_SYSTEM_MODE(mode))
3205                         pmc->pm_flags |= PMC_F_NEEDS_LOGFILE;
3206
3207                 /*
3208                  * Configure global pmc's immediately
3209                  */
3210
3211                 if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pmc))) {
3212
3213                         pmc_save_cpu_binding(&pb);
3214                         pmc_select_cpu(cpu);
3215
3216                         phw = pmc_pcpu[cpu]->pc_hwpmcs[n];
3217                         pcd = pmc_ri_to_classdep(md, n, &adjri);
3218
3219                         if ((phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) == 0 ||
3220                             (error = pcd->pcd_config_pmc(cpu, adjri, pmc)) != 0) {
3221                                 (void) pcd->pcd_release_pmc(cpu, adjri, pmc);
3222                                 pmc_destroy_pmc_descriptor(pmc);
3223                                 free(pmc, M_PMC);
3224                                 pmc = NULL;
3225                                 pmc_restore_cpu_binding(&pb);
3226                                 error = EPERM;
3227                                 break;
3228                         }
3229
3230                         pmc_restore_cpu_binding(&pb);
3231                 }
3232
3233                 pmc->pm_state    = PMC_STATE_ALLOCATED;
3234
3235                 /*
3236                  * mark row disposition
3237                  */
3238
3239                 if (PMC_IS_SYSTEM_MODE(mode))
3240                         PMC_MARK_ROW_STANDALONE(n);
3241                 else
3242                         PMC_MARK_ROW_THREAD(n);
3243
3244                 /*
3245                  * Register this PMC with the current thread as its owner.
3246                  */
3247
3248                 if ((error =
3249                     pmc_register_owner(curthread->td_proc, pmc)) != 0) {
3250                         pmc_release_pmc_descriptor(pmc);
3251                         free(pmc, M_PMC);
3252                         pmc = NULL;
3253                         break;
3254                 }
3255
3256                 /*
3257                  * Return the allocated index.
3258                  */
3259
3260                 pa.pm_pmcid = pmc->pm_id;
3261
3262                 error = copyout(&pa, arg, sizeof(pa));
3263         }
3264         break;
3265
3266
3267         /*
3268          * Attach a PMC to a process.
3269          */
3270
3271         case PMC_OP_PMCATTACH:
3272         {
3273                 struct pmc *pm;
3274                 struct proc *p;
3275                 struct pmc_op_pmcattach a;
3276
3277                 sx_assert(&pmc_sx, SX_XLOCKED);
3278
3279                 if ((error = copyin(arg, &a, sizeof(a))) != 0)
3280                         break;
3281
3282                 if (a.pm_pid < 0) {
3283                         error = EINVAL;
3284                         break;
3285                 } else if (a.pm_pid == 0)
3286                         a.pm_pid = td->td_proc->p_pid;
3287
3288                 if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
3289                         break;
3290
3291                 if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm))) {
3292                         error = EINVAL;
3293                         break;
3294                 }
3295
3296                 /* PMCs may be (re)attached only when allocated or stopped */
3297                 if (pm->pm_state == PMC_STATE_RUNNING) {
3298                         error = EBUSY;
3299                         break;
3300                 } else if (pm->pm_state != PMC_STATE_ALLOCATED &&
3301                     pm->pm_state != PMC_STATE_STOPPED) {
3302                         error = EINVAL;
3303                         break;
3304                 }
3305
3306                 /* lookup pid */
3307                 if ((p = pfind(a.pm_pid)) == NULL) {
3308                         error = ESRCH;
3309                         break;
3310                 }
3311
3312                 /*
3313                  * Ignore processes that are working on exiting.
3314                  */
3315                 if (p->p_flag & P_WEXIT) {
3316                         error = ESRCH;
3317                         PROC_UNLOCK(p); /* pfind() returns a locked process */
3318                         break;
3319                 }
3320
3321                 /*
3322                  * we are allowed to attach a PMC to a process if
3323                  * we can debug it.
3324                  */
3325                 error = p_candebug(curthread, p);
3326
3327                 PROC_UNLOCK(p);
3328
3329                 if (error == 0)
3330                         error = pmc_attach_process(p, pm);
3331         }
3332         break;
3333
3334
3335         /*
3336          * Detach an attached PMC from a process.
3337          */
3338
3339         case PMC_OP_PMCDETACH:
3340         {
3341                 struct pmc *pm;
3342                 struct proc *p;
3343                 struct pmc_op_pmcattach a;
3344
3345                 if ((error = copyin(arg, &a, sizeof(a))) != 0)
3346                         break;
3347
3348                 if (a.pm_pid < 0) {
3349                         error = EINVAL;
3350                         break;
3351                 } else if (a.pm_pid == 0)
3352                         a.pm_pid = td->td_proc->p_pid;
3353
3354                 if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
3355                         break;
3356
3357                 if ((p = pfind(a.pm_pid)) == NULL) {
3358                         error = ESRCH;
3359                         break;
3360                 }
3361
3362                 /*
3363                  * Treat processes that are in the process of exiting
3364                  * as if they were not present.
3365                  */
3366
3367                 if (p->p_flag & P_WEXIT)
3368                         error = ESRCH;
3369
3370                 PROC_UNLOCK(p); /* pfind() returns a locked process */
3371
3372                 if (error == 0)
3373                         error = pmc_detach_process(p, pm);
3374         }
3375         break;
3376
3377
3378         /*
3379          * Retrieve the MSR number associated with the counter
3380          * 'pmc_id'.  This allows processes to directly use RDPMC
3381          * instructions to read their PMCs, without the overhead of a
3382          * system call.
3383          */
3384
3385         case PMC_OP_PMCGETMSR:
3386         {
3387                 int adjri, ri;
3388                 struct pmc *pm;
3389                 struct pmc_target *pt;
3390                 struct pmc_op_getmsr gm;
3391                 struct pmc_classdep *pcd;
3392
3393                 PMC_DOWNGRADE_SX();
3394
3395                 if ((error = copyin(arg, &gm, sizeof(gm))) != 0)
3396                         break;
3397
3398                 if ((error = pmc_find_pmc(gm.pm_pmcid, &pm)) != 0)
3399                         break;
3400
3401                 /*
3402                  * The allocated PMC has to be a process virtual PMC,
3403                  * i.e., of type MODE_T[CS].  Global PMCs can only be
3404                  * read using the PMCREAD operation since they may be
3405                  * allocated on a different CPU than the one we could
3406                  * be running on at the time of the RDPMC instruction.
3407                  *
3408                  * The GETMSR operation is not allowed for PMCs that
3409                  * are inherited across processes.
3410                  */
3411
3412                 if (!PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)) ||
3413                     (pm->pm_flags & PMC_F_DESCENDANTS)) {
3414                         error = EINVAL;
3415                         break;
3416                 }
3417
3418                 /*
3419                  * It only makes sense to use a RDPMC (or its
3420                  * equivalent instruction on non-x86 architectures) on
3421                  * a process that has allocated and attached a PMC to
3422                  * itself.  Conversely the PMC is only allowed to have
3423                  * one process attached to it -- its owner.
3424                  */
3425
3426                 if ((pt = LIST_FIRST(&pm->pm_targets)) == NULL ||
3427                     LIST_NEXT(pt, pt_next) != NULL ||
3428                     pt->pt_process->pp_proc != pm->pm_owner->po_owner) {
3429                         error = EINVAL;
3430                         break;
3431                 }
3432
3433                 ri = PMC_TO_ROWINDEX(pm);
3434                 pcd = pmc_ri_to_classdep(md, ri, &adjri);
3435
3436                 /* PMC class has no 'GETMSR' support */
3437                 if (pcd->pcd_get_msr == NULL) {
3438                         error = ENOSYS;
3439                         break;
3440                 }
3441
3442                 if ((error = (*pcd->pcd_get_msr)(adjri, &gm.pm_msr)) < 0)
3443                         break;
3444
3445                 if ((error = copyout(&gm, arg, sizeof(gm))) < 0)
3446                         break;
3447
3448                 /*
3449                  * Mark our process as using MSRs.  Update machine
3450                  * state using a forced context switch.
3451                  */
3452
3453                 pt->pt_process->pp_flags |= PMC_PP_ENABLE_MSR_ACCESS;
3454                 pmc_force_context_switch();
3455
3456         }
3457         break;
3458
3459         /*
3460          * Release an allocated PMC
3461          */
3462
3463         case PMC_OP_PMCRELEASE:
3464         {
3465                 pmc_id_t pmcid;
3466                 struct pmc *pm;
3467                 struct pmc_owner *po;
3468                 struct pmc_op_simple sp;
3469
3470                 /*
3471                  * Find PMC pointer for the named PMC.
3472                  *
3473                  * Use pmc_release_pmc_descriptor() to switch off the
3474                  * PMC, remove all its target threads, and remove the
3475                  * PMC from its owner's list.
3476                  *
3477                  * Remove the owner record if this is the last PMC
3478                  * owned.
3479                  *
3480                  * Free up space.
3481                  */
3482
3483                 if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
3484                         break;
3485
3486                 pmcid = sp.pm_pmcid;
3487
3488                 if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
3489                         break;
3490
3491                 po = pm->pm_owner;
3492                 pmc_release_pmc_descriptor(pm);
3493                 pmc_maybe_remove_owner(po);
3494
3495                 free(pm, M_PMC);
3496         }
3497         break;
3498
3499
3500         /*
3501          * Read and/or write a PMC.
3502          */
3503
3504         case PMC_OP_PMCRW:
3505         {
3506                 int adjri;
3507                 struct pmc *pm;
3508                 uint32_t cpu, ri;
3509                 pmc_value_t oldvalue;
3510                 struct pmc_binding pb;
3511                 struct pmc_op_pmcrw prw;
3512                 struct pmc_classdep *pcd;
3513                 struct pmc_op_pmcrw *pprw;
3514
3515                 PMC_DOWNGRADE_SX();
3516
3517                 if ((error = copyin(arg, &prw, sizeof(prw))) != 0)
3518                         break;
3519
3520                 ri = 0;
3521                 PMCDBG(PMC,OPS,1, "rw id=%d flags=0x%x", prw.pm_pmcid,
3522                     prw.pm_flags);
3523
3524                 /* must have at least one flag set */
3525                 if ((prw.pm_flags & (PMC_F_OLDVALUE|PMC_F_NEWVALUE)) == 0) {
3526                         error = EINVAL;
3527                         break;
3528                 }
3529
3530                 /* locate pmc descriptor */
3531                 if ((error = pmc_find_pmc(prw.pm_pmcid, &pm)) != 0)
3532                         break;
3533
3534                 /* Can't read a PMC that hasn't been started. */
3535                 if (pm->pm_state != PMC_STATE_ALLOCATED &&
3536                     pm->pm_state != PMC_STATE_STOPPED &&
3537                     pm->pm_state != PMC_STATE_RUNNING) {
3538                         error = EINVAL;
3539                         break;
3540                 }
3541
3542                 /* writing a new value is allowed only for 'STOPPED' pmcs */
3543                 if (pm->pm_state == PMC_STATE_RUNNING &&
3544                     (prw.pm_flags & PMC_F_NEWVALUE)) {
3545                         error = EBUSY;
3546                         break;
3547                 }
3548
3549                 if (PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm))) {
3550
3551                         /*
3552                          * If this PMC is attached to its owner (i.e.,
3553                          * the process requesting this operation) and
3554                          * is running, then attempt to get an
3555                          * upto-date reading from hardware for a READ.
3556                          * Writes are only allowed when the PMC is
3557                          * stopped, so only update the saved value
3558                          * field.
3559                          *
3560                          * If the PMC is not running, or is not
3561                          * attached to its owner, read/write to the
3562                          * savedvalue field.
3563                          */
3564
3565                         ri = PMC_TO_ROWINDEX(pm);
3566                         pcd = pmc_ri_to_classdep(md, ri, &adjri);
3567
3568                         mtx_pool_lock_spin(pmc_mtxpool, pm);
3569                         cpu = curthread->td_oncpu;
3570
3571                         if (prw.pm_flags & PMC_F_OLDVALUE) {
3572                                 if ((pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) &&
3573                                     (pm->pm_state == PMC_STATE_RUNNING))
3574                                         error = (*pcd->pcd_read_pmc)(cpu, adjri,
3575                                             &oldvalue);
3576                                 else
3577                                         oldvalue = pm->pm_gv.pm_savedvalue;
3578                         }
3579                         if (prw.pm_flags & PMC_F_NEWVALUE)
3580                                 pm->pm_gv.pm_savedvalue = prw.pm_value;
3581
3582                         mtx_pool_unlock_spin(pmc_mtxpool, pm);
3583
3584                 } else { /* System mode PMCs */
3585                         cpu = PMC_TO_CPU(pm);
3586                         ri  = PMC_TO_ROWINDEX(pm);
3587                         pcd = pmc_ri_to_classdep(md, ri, &adjri);
3588
3589                         if (!pmc_cpu_is_active(cpu)) {
3590                                 error = ENXIO;
3591                                 break;
3592                         }
3593
3594                         /* move this thread to CPU 'cpu' */
3595                         pmc_save_cpu_binding(&pb);
3596                         pmc_select_cpu(cpu);
3597
3598                         critical_enter();
3599                         /* save old value */
3600                         if (prw.pm_flags & PMC_F_OLDVALUE)
3601                                 if ((error = (*pcd->pcd_read_pmc)(cpu, adjri,
3602                                          &oldvalue)))
3603                                         goto error;
3604                         /* write out new value */
3605                         if (prw.pm_flags & PMC_F_NEWVALUE)
3606                                 error = (*pcd->pcd_write_pmc)(cpu, adjri,
3607                                     prw.pm_value);
3608                 error:
3609                         critical_exit();
3610                         pmc_restore_cpu_binding(&pb);
3611                         if (error)
3612                                 break;
3613                 }
3614
3615                 pprw = (struct pmc_op_pmcrw *) arg;
3616
3617 #ifdef  DEBUG
3618                 if (prw.pm_flags & PMC_F_NEWVALUE)
3619                         PMCDBG(PMC,OPS,2, "rw id=%d new %jx -> old %jx",
3620                             ri, prw.pm_value, oldvalue);
3621                 else if (prw.pm_flags & PMC_F_OLDVALUE)
3622                         PMCDBG(PMC,OPS,2, "rw id=%d -> old %jx", ri, oldvalue);
3623 #endif
3624
3625                 /* return old value if requested */
3626                 if (prw.pm_flags & PMC_F_OLDVALUE)
3627                         if ((error = copyout(&oldvalue, &pprw->pm_value,
3628                                  sizeof(prw.pm_value))))
3629                                 break;
3630
3631         }
3632         break;
3633
3634
3635         /*
3636          * Set the sampling rate for a sampling mode PMC and the
3637          * initial count for a counting mode PMC.
3638          */
3639
3640         case PMC_OP_PMCSETCOUNT:
3641         {
3642                 struct pmc *pm;
3643                 struct pmc_op_pmcsetcount sc;
3644
3645                 PMC_DOWNGRADE_SX();
3646
3647                 if ((error = copyin(arg, &sc, sizeof(sc))) != 0)
3648                         break;
3649
3650                 if ((error = pmc_find_pmc(sc.pm_pmcid, &pm)) != 0)
3651                         break;
3652
3653                 if (pm->pm_state == PMC_STATE_RUNNING) {
3654                         error = EBUSY;
3655                         break;
3656                 }
3657
3658                 if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
3659                         pm->pm_sc.pm_reloadcount = sc.pm_count;
3660                 else
3661                         pm->pm_sc.pm_initial = sc.pm_count;
3662         }
3663         break;
3664
3665
3666         /*
3667          * Start a PMC.
3668          */
3669
3670         case PMC_OP_PMCSTART:
3671         {
3672                 pmc_id_t pmcid;
3673                 struct pmc *pm;
3674                 struct pmc_op_simple sp;
3675
3676                 sx_assert(&pmc_sx, SX_XLOCKED);
3677
3678                 if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
3679                         break;
3680
3681                 pmcid = sp.pm_pmcid;
3682
3683                 if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
3684                         break;
3685
3686                 KASSERT(pmcid == pm->pm_id,
3687                     ("[pmc,%d] pmcid %x != id %x", __LINE__,
3688                         pm->pm_id, pmcid));
3689
3690                 if (pm->pm_state == PMC_STATE_RUNNING) /* already running */
3691                         break;
3692                 else if (pm->pm_state != PMC_STATE_STOPPED &&
3693                     pm->pm_state != PMC_STATE_ALLOCATED) {
3694                         error = EINVAL;
3695                         break;
3696                 }
3697
3698                 error = pmc_start(pm);
3699         }
3700         break;
3701
3702
3703         /*
3704          * Stop a PMC.
3705          */
3706
3707         case PMC_OP_PMCSTOP:
3708         {
3709                 pmc_id_t pmcid;
3710                 struct pmc *pm;
3711                 struct pmc_op_simple sp;
3712
3713                 PMC_DOWNGRADE_SX();
3714
3715                 if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
3716                         break;
3717
3718                 pmcid = sp.pm_pmcid;
3719
3720                 /*
3721                  * Mark the PMC as inactive and invoke the MD stop
3722                  * routines if needed.
3723                  */
3724
3725                 if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
3726                         break;
3727
3728                 KASSERT(pmcid == pm->pm_id,
3729                     ("[pmc,%d] pmc id %x != pmcid %x", __LINE__,
3730                         pm->pm_id, pmcid));
3731
3732                 if (pm->pm_state == PMC_STATE_STOPPED) /* already stopped */
3733                         break;
3734                 else if (pm->pm_state != PMC_STATE_RUNNING) {
3735                         error = EINVAL;
3736                         break;
3737                 }
3738
3739                 error = pmc_stop(pm);
3740         }
3741         break;
3742
3743
3744         /*
3745          * Write a user supplied value to the log file.
3746          */
3747
3748         case PMC_OP_WRITELOG:
3749         {
3750                 struct pmc_op_writelog wl;
3751                 struct pmc_owner *po;
3752
3753                 PMC_DOWNGRADE_SX();
3754
3755                 if ((error = copyin(arg, &wl, sizeof(wl))) != 0)
3756                         break;
3757
3758                 if ((po = pmc_find_owner_descriptor(td->td_proc)) == NULL) {
3759                         error = EINVAL;
3760                         break;
3761                 }
3762
3763                 if ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0) {
3764                         error = EINVAL;
3765                         break;
3766                 }
3767
3768                 error = pmclog_process_userlog(po, &wl);
3769         }
3770         break;
3771
3772
3773         default:
3774                 error = EINVAL;
3775                 break;
3776         }
3777
3778         if (is_sx_locked != 0) {
3779                 if (is_sx_downgraded)
3780                         sx_sunlock(&pmc_sx);
3781                 else
3782                         sx_xunlock(&pmc_sx);
3783         }
3784
3785         if (error)
3786                 atomic_add_int(&pmc_stats.pm_syscall_errors, 1);
3787
3788         PICKUP_GIANT();
3789
3790         return error;
3791 }
3792
3793 /*
3794  * Helper functions
3795  */
3796
3797
3798 /*
3799  * Mark the thread as needing callchain capture and post an AST.  The
3800  * actual callchain capture will be done in a context where it is safe
3801  * to take page faults.
3802  */
3803
3804 static void
3805 pmc_post_callchain_callback(void)
3806 {
3807         struct thread *td;
3808
3809         td = curthread;
3810
3811         KASSERT((td->td_pflags & TDP_CALLCHAIN) == 0,
3812             ("[pmc,%d] thread %p already marked for callchain capture",
3813                 __LINE__, (void *) td));
3814
3815         /*
3816          * Mark this thread as needing callchain capture.
3817          * `td->td_pflags' will be safe to touch because this thread
3818          * was in user space when it was interrupted.
3819          */
3820         td->td_pflags |= TDP_CALLCHAIN;
3821
3822         /*
3823          * Don't let this thread migrate between CPUs until callchain
3824          * capture completes.
3825          */
3826         sched_pin();
3827
3828         return;
3829 }
3830
3831 /*
3832  * Interrupt processing.
3833  *
3834  * Find a free slot in the per-cpu array of samples and capture the
3835  * current callchain there.  If a sample was successfully added, a bit
3836  * is set in mask 'pmc_cpumask' denoting that the DO_SAMPLES hook
3837  * needs to be invoked from the clock handler.
3838  *
3839  * This function is meant to be called from an NMI handler.  It cannot
3840  * use any of the locking primitives supplied by the OS.
3841  */
3842
3843 int
3844 pmc_process_interrupt(int cpu, struct pmc *pm, struct trapframe *tf,
3845     int inuserspace)
3846 {
3847         int error, callchaindepth;
3848         struct thread *td;
3849         struct pmc_sample *ps;
3850         struct pmc_samplebuffer *psb;
3851
3852         error = 0;
3853
3854         /*
3855          * Allocate space for a sample buffer.
3856          */
3857         psb = pmc_pcpu[cpu]->pc_sb;
3858
3859         ps = psb->ps_write;
3860         if (ps->ps_nsamples) {  /* in use, reader hasn't caught up */
3861                 pm->pm_stalled = 1;
3862                 atomic_add_int(&pmc_stats.pm_intr_bufferfull, 1);
3863                 PMCDBG(SAM,INT,1,"(spc) cpu=%d pm=%p tf=%p um=%d wr=%d rd=%d",
3864                     cpu, pm, (void *) tf, inuserspace,
3865                     (int) (psb->ps_write - psb->ps_samples),
3866                     (int) (psb->ps_read - psb->ps_samples));
3867                 error = ENOMEM;
3868                 goto done;
3869         }
3870
3871
3872         /* Fill in entry. */
3873         PMCDBG(SAM,INT,1,"cpu=%d pm=%p tf=%p um=%d wr=%d rd=%d", cpu, pm,
3874             (void *) tf, inuserspace,
3875             (int) (psb->ps_write - psb->ps_samples),
3876             (int) (psb->ps_read - psb->ps_samples));
3877
3878         KASSERT(pm->pm_runcount >= 0,
3879             ("[pmc,%d] pm=%p runcount %d", __LINE__, (void *) pm,
3880                 pm->pm_runcount));
3881
3882         atomic_add_rel_32(&pm->pm_runcount, 1); /* hold onto PMC */
3883         ps->ps_pmc = pm;
3884         if ((td = curthread) && td->td_proc)
3885                 ps->ps_pid = td->td_proc->p_pid;
3886         else
3887                 ps->ps_pid = -1;
3888         ps->ps_cpu = cpu;
3889         ps->ps_td = td;
3890         ps->ps_flags = inuserspace ? PMC_CC_F_USERSPACE : 0;
3891
3892         callchaindepth = (pm->pm_flags & PMC_F_CALLCHAIN) ?
3893             pmc_callchaindepth : 1;
3894
3895         if (callchaindepth == 1)
3896                 ps->ps_pc[0] = PMC_TRAPFRAME_TO_PC(tf);
3897         else {
3898                 /*
3899                  * Kernel stack traversals can be done immediately,
3900                  * while we defer to an AST for user space traversals.
3901                  */
3902                 if (!inuserspace)
3903                         callchaindepth =
3904                             pmc_save_kernel_callchain(ps->ps_pc,
3905                                 callchaindepth, tf);
3906                 else {
3907                         pmc_post_callchain_callback();
3908                         callchaindepth = PMC_SAMPLE_INUSE;
3909                 }
3910         }
3911
3912         ps->ps_nsamples = callchaindepth;       /* mark entry as in use */
3913
3914         /* increment write pointer, modulo ring buffer size */
3915         ps++;
3916         if (ps == psb->ps_fence)
3917                 psb->ps_write = psb->ps_samples;
3918         else
3919                 psb->ps_write = ps;
3920
3921  done:
3922         /* mark CPU as needing processing */
3923         atomic_set_rel_int(&pmc_cpumask, (1 << cpu));
3924
3925         return (error);
3926 }
3927
3928 /*
3929  * Capture a user call chain.  This function will be called from ast()
3930  * before control returns to userland and before the process gets
3931  * rescheduled.
3932  */
3933
3934 static void
3935 pmc_capture_user_callchain(int cpu, struct trapframe *tf)
3936 {
3937         int i;
3938         struct pmc *pm;
3939         struct thread *td;
3940         struct pmc_sample *ps;
3941         struct pmc_samplebuffer *psb;
3942 #ifdef  INVARIANTS
3943         int ncallchains;
3944 #endif
3945
3946         sched_unpin();  /* Can migrate safely now. */
3947
3948         psb = pmc_pcpu[cpu]->pc_sb;
3949         td = curthread;
3950
3951         KASSERT(td->td_pflags & TDP_CALLCHAIN,
3952             ("[pmc,%d] Retrieving callchain for thread that doesn't want it",
3953                 __LINE__));
3954
3955 #ifdef  INVARIANTS
3956         ncallchains = 0;
3957 #endif
3958
3959         /*
3960          * Iterate through all deferred callchain requests.
3961          */
3962
3963         ps = psb->ps_samples;
3964         for (i = 0; i < pmc_nsamples; i++, ps++) {
3965
3966                 if (ps->ps_nsamples != PMC_SAMPLE_INUSE)
3967                         continue;
3968                 if (ps->ps_td != td)
3969                         continue;
3970
3971                 KASSERT(ps->ps_cpu == cpu,
3972                     ("[pmc,%d] cpu mismatch ps_cpu=%d pcpu=%d", __LINE__,
3973                         ps->ps_cpu, PCPU_GET(cpuid)));
3974
3975                 pm = ps->ps_pmc;
3976
3977                 KASSERT(pm->pm_flags & PMC_F_CALLCHAIN,
3978                     ("[pmc,%d] Retrieving callchain for PMC that doesn't "
3979                         "want it", __LINE__));
3980
3981                 KASSERT(pm->pm_runcount > 0,
3982                     ("[pmc,%d] runcount %d", __LINE__, pm->pm_runcount));
3983
3984                 /*
3985                  * Retrieve the callchain and mark the sample buffer
3986                  * as 'processable' by the timer tick sweep code.
3987                  */
3988                 ps->ps_nsamples = pmc_save_user_callchain(ps->ps_pc,
3989                     pmc_callchaindepth, tf);
3990
3991 #ifdef  INVARIANTS
3992                 ncallchains++;
3993 #endif
3994
3995         }
3996
3997         KASSERT(ncallchains > 0,
3998             ("[pmc,%d] cpu %d didn't find a sample to collect", __LINE__,
3999                 cpu));
4000
4001         return;
4002 }
4003
4004
4005 /*
4006  * Process saved PC samples.
4007  */
4008
4009 static void
4010 pmc_process_samples(int cpu)
4011 {
4012         struct pmc *pm;
4013         int adjri, n;
4014         struct thread *td;
4015         struct pmc_owner *po;
4016         struct pmc_sample *ps;
4017         struct pmc_classdep *pcd;
4018         struct pmc_samplebuffer *psb;
4019
4020         KASSERT(PCPU_GET(cpuid) == cpu,
4021             ("[pmc,%d] not on the correct CPU pcpu=%d cpu=%d", __LINE__,
4022                 PCPU_GET(cpuid), cpu));
4023
4024         psb = pmc_pcpu[cpu]->pc_sb;
4025
4026         for (n = 0; n < pmc_nsamples; n++) { /* bound on #iterations */
4027
4028                 ps = psb->ps_read;
4029                 if (ps->ps_nsamples == PMC_SAMPLE_FREE)
4030                         break;
4031                 if (ps->ps_nsamples == PMC_SAMPLE_INUSE) {
4032                         /* Need a rescan at a later time. */
4033                         atomic_set_rel_int(&pmc_cpumask, (1 << cpu));
4034                         break;
4035                 }
4036
4037                 pm = ps->ps_pmc;
4038
4039                 KASSERT(pm->pm_runcount > 0,
4040                     ("[pmc,%d] pm=%p runcount %d", __LINE__, (void *) pm,
4041                         pm->pm_runcount));
4042
4043                 po = pm->pm_owner;
4044
4045                 KASSERT(PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)),
4046                     ("[pmc,%d] pmc=%p non-sampling mode=%d", __LINE__,
4047                         pm, PMC_TO_MODE(pm)));
4048
4049                 /* Ignore PMCs that have been switched off */
4050                 if (pm->pm_state != PMC_STATE_RUNNING)
4051                         goto entrydone;
4052
4053                 PMCDBG(SAM,OPS,1,"cpu=%d pm=%p n=%d fl=%x wr=%d rd=%d", cpu,
4054                     pm, ps->ps_nsamples, ps->ps_flags,
4055                     (int) (psb->ps_write - psb->ps_samples),
4056                     (int) (psb->ps_read - psb->ps_samples));
4057
4058                 /*
4059                  * If this is a process-mode PMC that is attached to
4060                  * its owner, and if the PC is in user mode, update
4061                  * profiling statistics like timer-based profiling
4062                  * would have done.
4063                  */
4064                 if (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) {
4065                         if (ps->ps_flags & PMC_CC_F_USERSPACE) {
4066                                 td = FIRST_THREAD_IN_PROC(po->po_owner);
4067                                 addupc_intr(td, ps->ps_pc[0], 1);
4068                         }
4069                         goto entrydone;
4070                 }
4071
4072                 /*
4073                  * Otherwise, this is either a sampling mode PMC that
4074                  * is attached to a different process than its owner,
4075                  * or a system-wide sampling PMC.  Dispatch a log
4076                  * entry to the PMC's owner process.
4077                  */
4078
4079                 pmclog_process_callchain(pm, ps);
4080
4081         entrydone:
4082                 ps->ps_nsamples = 0;    /* mark entry as free */
4083                 atomic_subtract_rel_32(&pm->pm_runcount, 1);
4084
4085                 /* increment read pointer, modulo sample size */
4086                 if (++ps == psb->ps_fence)
4087                         psb->ps_read = psb->ps_samples;
4088                 else
4089                         psb->ps_read = ps;
4090         }
4091
4092         atomic_add_int(&pmc_stats.pm_log_sweeps, 1);
4093
4094         /* Do not re-enable stalled PMCs if we failed to process any samples */
4095         if (n == 0)
4096                 return;
4097
4098         /*
4099          * Restart any stalled sampling PMCs on this CPU.
4100          *
4101          * If the NMI handler sets the pm_stalled field of a PMC after
4102          * the check below, we'll end up processing the stalled PMC at
4103          * the next hardclock tick.
4104          */
4105         for (n = 0; n < md->pmd_npmc; n++) {
4106                 pcd = pmc_ri_to_classdep(md, n, &adjri);
4107                 KASSERT(pcd != NULL,
4108                     ("[pmc,%d] null pcd ri=%d", __LINE__, n));
4109                 (void) (*pcd->pcd_get_config)(cpu,adjri,&pm);
4110
4111                 if (pm == NULL ||                        /* !cfg'ed */
4112                     pm->pm_state != PMC_STATE_RUNNING || /* !active */
4113                     !PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)) || /* !sampling */
4114                     pm->pm_stalled == 0) /* !stalled */
4115                         continue;
4116
4117                 pm->pm_stalled = 0;
4118                 (*pcd->pcd_start_pmc)(cpu, adjri);
4119         }
4120 }
4121
4122 /*
4123  * Event handlers.
4124  */
4125
4126 /*
4127  * Handle a process exit.
4128  *
4129  * Remove this process from all hash tables.  If this process
4130  * owned any PMCs, turn off those PMCs and deallocate them,
4131  * removing any associations with target processes.
4132  *
4133  * This function will be called by the last 'thread' of a
4134  * process.
4135  *
4136  * XXX This eventhandler gets called early in the exit process.
4137  * Consider using a 'hook' invocation from thread_exit() or equivalent
4138  * spot.  Another negative is that kse_exit doesn't seem to call
4139  * exit1() [??].
4140  *
4141  */
4142
4143 static void
4144 pmc_process_exit(void *arg __unused, struct proc *p)
4145 {
4146         struct pmc *pm;
4147         int adjri, cpu;
4148         unsigned int ri;
4149         int is_using_hwpmcs;
4150         struct pmc_owner *po;
4151         struct pmc_process *pp;
4152         struct pmc_classdep *pcd;
4153         pmc_value_t newvalue, tmp;
4154
4155         PROC_LOCK(p);
4156         is_using_hwpmcs = p->p_flag & P_HWPMC;
4157         PROC_UNLOCK(p);
4158
4159         /*
4160          * Log a sysexit event to all SS PMC owners.
4161          */
4162         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
4163             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
4164                     pmclog_process_sysexit(po, p->p_pid);
4165
4166         if (!is_using_hwpmcs)
4167                 return;
4168
4169         PMC_GET_SX_XLOCK();
4170         PMCDBG(PRC,EXT,1,"process-exit proc=%p (%d, %s)", p, p->p_pid,
4171             p->p_comm);
4172
4173         /*
4174          * Since this code is invoked by the last thread in an exiting
4175          * process, we would have context switched IN at some prior
4176          * point.  However, with PREEMPTION, kernel mode context
4177          * switches may happen any time, so we want to disable a
4178          * context switch OUT till we get any PMCs targetting this
4179          * process off the hardware.
4180          *
4181          * We also need to atomically remove this process'
4182          * entry from our target process hash table, using
4183          * PMC_FLAG_REMOVE.
4184          */
4185         PMCDBG(PRC,EXT,1, "process-exit proc=%p (%d, %s)", p, p->p_pid,
4186             p->p_comm);
4187
4188         critical_enter(); /* no preemption */
4189
4190         cpu = curthread->td_oncpu;
4191
4192         if ((pp = pmc_find_process_descriptor(p,
4193                  PMC_FLAG_REMOVE)) != NULL) {
4194
4195                 PMCDBG(PRC,EXT,2,
4196                     "process-exit proc=%p pmc-process=%p", p, pp);
4197
4198                 /*
4199                  * The exiting process could the target of
4200                  * some PMCs which will be running on
4201                  * currently executing CPU.
4202                  *
4203                  * We need to turn these PMCs off like we
4204                  * would do at context switch OUT time.
4205                  */
4206                 for (ri = 0; ri < md->pmd_npmc; ri++) {
4207
4208                         /*
4209                          * Pick up the pmc pointer from hardware
4210                          * state similar to the CSW_OUT code.
4211                          */
4212                         pm = NULL;
4213
4214                         pcd = pmc_ri_to_classdep(md, ri, &adjri);
4215
4216                         (void) (*pcd->pcd_get_config)(cpu, adjri, &pm);
4217
4218                         PMCDBG(PRC,EXT,2, "ri=%d pm=%p", ri, pm);
4219
4220                         if (pm == NULL ||
4221                             !PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)))
4222                                 continue;
4223
4224                         PMCDBG(PRC,EXT,2, "ppmcs[%d]=%p pm=%p "
4225                             "state=%d", ri, pp->pp_pmcs[ri].pp_pmc,
4226                             pm, pm->pm_state);
4227
4228                         KASSERT(PMC_TO_ROWINDEX(pm) == ri,
4229                             ("[pmc,%d] ri mismatch pmc(%d) ri(%d)",
4230                                 __LINE__, PMC_TO_ROWINDEX(pm), ri));
4231
4232                         KASSERT(pm == pp->pp_pmcs[ri].pp_pmc,
4233                             ("[pmc,%d] pm %p != pp_pmcs[%d] %p",
4234                                 __LINE__, pm, ri, pp->pp_pmcs[ri].pp_pmc));
4235
4236                         (void) pcd->pcd_stop_pmc(cpu, adjri);
4237
4238                         KASSERT(pm->pm_runcount > 0,
4239                             ("[pmc,%d] bad runcount ri %d rc %d",
4240                                 __LINE__, ri, pm->pm_runcount));
4241
4242                         /* Stop hardware only if it is actually running */
4243                         if (pm->pm_state == PMC_STATE_RUNNING &&
4244                             pm->pm_stalled == 0) {
4245                                 pcd->pcd_read_pmc(cpu, adjri, &newvalue);
4246                                 tmp = newvalue -
4247                                     PMC_PCPU_SAVED(cpu,ri);
4248
4249                                 mtx_pool_lock_spin(pmc_mtxpool, pm);
4250                                 pm->pm_gv.pm_savedvalue += tmp;
4251                                 pp->pp_pmcs[ri].pp_pmcval += tmp;
4252                                 mtx_pool_unlock_spin(pmc_mtxpool, pm);
4253                         }
4254
4255                         atomic_subtract_rel_32(&pm->pm_runcount,1);
4256
4257                         KASSERT((int) pm->pm_runcount >= 0,
4258                             ("[pmc,%d] runcount is %d", __LINE__, ri));
4259
4260                         (void) pcd->pcd_config_pmc(cpu, adjri, NULL);
4261                 }
4262
4263                 /*
4264                  * Inform the MD layer of this pseudo "context switch
4265                  * out"
4266                  */
4267                 (void) md->pmd_switch_out(pmc_pcpu[cpu], pp);
4268
4269                 critical_exit(); /* ok to be pre-empted now */
4270
4271                 /*
4272                  * Unlink this process from the PMCs that are
4273                  * targetting it.  This will send a signal to
4274                  * all PMC owner's whose PMCs are orphaned.
4275                  *
4276                  * Log PMC value at exit time if requested.
4277                  */
4278                 for (ri = 0; ri < md->pmd_npmc; ri++)
4279                         if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL) {
4280                                 if (pm->pm_flags & PMC_F_NEEDS_LOGFILE &&
4281                                     PMC_IS_COUNTING_MODE(PMC_TO_MODE(pm)))
4282                                         pmclog_process_procexit(pm, pp);
4283                                 pmc_unlink_target_process(pm, pp);
4284                         }
4285                 free(pp, M_PMC);
4286
4287         } else
4288                 critical_exit(); /* pp == NULL */
4289
4290
4291         /*
4292          * If the process owned PMCs, free them up and free up
4293          * memory.
4294          */
4295         if ((po = pmc_find_owner_descriptor(p)) != NULL) {
4296                 pmc_remove_owner(po);
4297                 pmc_destroy_owner_descriptor(po);
4298         }
4299
4300         sx_xunlock(&pmc_sx);
4301 }
4302
4303 /*
4304  * Handle a process fork.
4305  *
4306  * If the parent process 'p1' is under HWPMC monitoring, then copy
4307  * over any attached PMCs that have 'do_descendants' semantics.
4308  */
4309
4310 static void
4311 pmc_process_fork(void *arg __unused, struct proc *p1, struct proc *newproc,
4312     int flags)
4313 {
4314         int is_using_hwpmcs;
4315         unsigned int ri;
4316         uint32_t do_descendants;
4317         struct pmc *pm;
4318         struct pmc_owner *po;
4319         struct pmc_process *ppnew, *ppold;
4320
4321         (void) flags;           /* unused parameter */
4322
4323         PROC_LOCK(p1);
4324         is_using_hwpmcs = p1->p_flag & P_HWPMC;
4325         PROC_UNLOCK(p1);
4326
4327         /*
4328          * If there are system-wide sampling PMCs active, we need to
4329          * log all fork events to their owner's logs.
4330          */
4331
4332         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
4333             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
4334                     pmclog_process_procfork(po, p1->p_pid, newproc->p_pid);
4335
4336         if (!is_using_hwpmcs)
4337                 return;
4338
4339         PMC_GET_SX_XLOCK();
4340         PMCDBG(PMC,FRK,1, "process-fork proc=%p (%d, %s) -> %p", p1,
4341             p1->p_pid, p1->p_comm, newproc);
4342
4343         /*
4344          * If the parent process (curthread->td_proc) is a
4345          * target of any PMCs, look for PMCs that are to be
4346          * inherited, and link these into the new process
4347          * descriptor.
4348          */
4349         if ((ppold = pmc_find_process_descriptor(curthread->td_proc,
4350                  PMC_FLAG_NONE)) == NULL)
4351                 goto done;              /* nothing to do */
4352
4353         do_descendants = 0;
4354         for (ri = 0; ri < md->pmd_npmc; ri++)
4355                 if ((pm = ppold->pp_pmcs[ri].pp_pmc) != NULL)
4356                         do_descendants |= pm->pm_flags & PMC_F_DESCENDANTS;
4357         if (do_descendants == 0) /* nothing to do */
4358                 goto done;
4359
4360         /* allocate a descriptor for the new process  */
4361         if ((ppnew = pmc_find_process_descriptor(newproc,
4362                  PMC_FLAG_ALLOCATE)) == NULL)
4363                 goto done;
4364
4365         /*
4366          * Run through all PMCs that were targeting the old process
4367          * and which specified F_DESCENDANTS and attach them to the
4368          * new process.
4369          *
4370          * Log the fork event to all owners of PMCs attached to this
4371          * process, if not already logged.
4372          */
4373         for (ri = 0; ri < md->pmd_npmc; ri++)
4374                 if ((pm = ppold->pp_pmcs[ri].pp_pmc) != NULL &&
4375                     (pm->pm_flags & PMC_F_DESCENDANTS)) {
4376                         pmc_link_target_process(pm, ppnew);
4377                         po = pm->pm_owner;
4378                         if (po->po_sscount == 0 &&
4379                             po->po_flags & PMC_PO_OWNS_LOGFILE)
4380                                 pmclog_process_procfork(po, p1->p_pid,
4381                                     newproc->p_pid);
4382                 }
4383
4384         /*
4385          * Now mark the new process as being tracked by this driver.
4386          */
4387         PROC_LOCK(newproc);
4388         newproc->p_flag |= P_HWPMC;
4389         PROC_UNLOCK(newproc);
4390
4391  done:
4392         sx_xunlock(&pmc_sx);
4393 }
4394
4395
4396 /*
4397  * initialization
4398  */
4399
4400 static const char *pmc_name_of_pmcclass[] = {
4401 #undef  __PMC_CLASS
4402 #define __PMC_CLASS(N) #N ,
4403         __PMC_CLASSES()
4404 };
4405
4406 static int
4407 pmc_initialize(void)
4408 {
4409         int c, cpu, error, n, ri;
4410         unsigned int maxcpu;
4411         struct pmc_binding pb;
4412         struct pmc_sample *ps;
4413         struct pmc_classdep *pcd;
4414         struct pmc_samplebuffer *sb;
4415
4416         md = NULL;
4417         error = 0;
4418
4419 #ifdef  DEBUG
4420         /* parse debug flags first */
4421         if (TUNABLE_STR_FETCH(PMC_SYSCTL_NAME_PREFIX "debugflags",
4422                 pmc_debugstr, sizeof(pmc_debugstr)))
4423                 pmc_debugflags_parse(pmc_debugstr,
4424                     pmc_debugstr+strlen(pmc_debugstr));
4425 #endif
4426
4427         PMCDBG(MOD,INI,0, "PMC Initialize (version %x)", PMC_VERSION);
4428
4429         /* check kernel version */
4430         if (pmc_kernel_version != PMC_VERSION) {
4431                 if (pmc_kernel_version == 0)
4432                         printf("hwpmc: this kernel has not been compiled with "
4433                             "'options HWPMC_HOOKS'.\n");
4434                 else
4435                         printf("hwpmc: kernel version (0x%x) does not match "
4436                             "module version (0x%x).\n", pmc_kernel_version,
4437                             PMC_VERSION);
4438                 return EPROGMISMATCH;
4439         }
4440
4441         /*
4442          * check sysctl parameters
4443          */
4444
4445         if (pmc_hashsize <= 0) {
4446                 (void) printf("hwpmc: tunable \"hashsize\"=%d must be "
4447                     "greater than zero.\n", pmc_hashsize);
4448                 pmc_hashsize = PMC_HASH_SIZE;
4449         }
4450
4451         if (pmc_nsamples <= 0 || pmc_nsamples > 65535) {
4452                 (void) printf("hwpmc: tunable \"nsamples\"=%d out of "
4453                     "range.\n", pmc_nsamples);
4454                 pmc_nsamples = PMC_NSAMPLES;
4455         }
4456
4457         if (pmc_callchaindepth <= 0 ||
4458             pmc_callchaindepth > PMC_CALLCHAIN_DEPTH_MAX) {
4459                 (void) printf("hwpmc: tunable \"callchaindepth\"=%d out of "
4460                     "range.\n", pmc_callchaindepth);
4461                 pmc_callchaindepth = PMC_CALLCHAIN_DEPTH;
4462         }
4463
4464         md = pmc_md_initialize();
4465
4466         if (md == NULL)
4467                 return (ENOSYS);
4468
4469         KASSERT(md->pmd_nclass >= 1 && md->pmd_npmc >= 1,
4470             ("[pmc,%d] no classes or pmcs", __LINE__));
4471
4472         /* Compute the map from row-indices to classdep pointers. */
4473         pmc_rowindex_to_classdep = malloc(sizeof(struct pmc_classdep *) *
4474             md->pmd_npmc, M_PMC, M_WAITOK|M_ZERO);
4475
4476         for (n = 0; n < md->pmd_npmc; n++)
4477                 pmc_rowindex_to_classdep[n] = NULL;
4478         for (ri = c = 0; c < md->pmd_nclass; c++) {
4479                 pcd = &md->pmd_classdep[c];
4480                 for (n = 0; n < pcd->pcd_num; n++, ri++)
4481                         pmc_rowindex_to_classdep[ri] = pcd;
4482         }
4483
4484         KASSERT(ri == md->pmd_npmc,
4485             ("[pmc,%d] npmc miscomputed: ri=%d, md->npmc=%d", __LINE__,
4486             ri, md->pmd_npmc));
4487
4488         maxcpu = pmc_cpu_max();
4489
4490         /* allocate space for the per-cpu array */
4491         pmc_pcpu = malloc(maxcpu * sizeof(struct pmc_cpu *), M_PMC,
4492             M_WAITOK|M_ZERO);
4493
4494         /* per-cpu 'saved values' for managing process-mode PMCs */
4495         pmc_pcpu_saved = malloc(sizeof(pmc_value_t) * maxcpu * md->pmd_npmc,
4496             M_PMC, M_WAITOK);
4497
4498         /* Perform CPU-dependent initialization. */
4499         pmc_save_cpu_binding(&pb);
4500         error = 0;
4501         for (cpu = 0; error == 0 && cpu < maxcpu; cpu++) {
4502                 if (!pmc_cpu_is_active(cpu))
4503                         continue;
4504                 pmc_select_cpu(cpu);
4505                 pmc_pcpu[cpu] = malloc(sizeof(struct pmc_cpu) +
4506                     md->pmd_npmc * sizeof(struct pmc_hw *), M_PMC,
4507                     M_WAITOK|M_ZERO);
4508                 if (md->pmd_pcpu_init)
4509                         error = md->pmd_pcpu_init(md, cpu);
4510                 for (n = 0; error == 0 && n < md->pmd_nclass; n++)
4511                         error = md->pmd_classdep[n].pcd_pcpu_init(md, cpu);
4512         }
4513         pmc_restore_cpu_binding(&pb);
4514
4515         if (error)
4516                 return (error);
4517
4518         /* allocate space for the sample array */
4519         for (cpu = 0; cpu < maxcpu; cpu++) {
4520                 if (!pmc_cpu_is_active(cpu))
4521                         continue;
4522
4523                 sb = malloc(sizeof(struct pmc_samplebuffer) +
4524                     pmc_nsamples * sizeof(struct pmc_sample), M_PMC,
4525                     M_WAITOK|M_ZERO);
4526                 sb->ps_read = sb->ps_write = sb->ps_samples;
4527                 sb->ps_fence = sb->ps_samples + pmc_nsamples;
4528
4529                 KASSERT(pmc_pcpu[cpu] != NULL,
4530                     ("[pmc,%d] cpu=%d Null per-cpu data", __LINE__, cpu));
4531
4532                 sb->ps_callchains = malloc(pmc_callchaindepth * pmc_nsamples *
4533                     sizeof(uintptr_t), M_PMC, M_WAITOK|M_ZERO);
4534
4535                 for (n = 0, ps = sb->ps_samples; n < pmc_nsamples; n++, ps++)
4536                         ps->ps_pc = sb->ps_callchains +
4537                             (n * pmc_callchaindepth);
4538
4539                 pmc_pcpu[cpu]->pc_sb = sb;
4540         }
4541
4542         /* allocate space for the row disposition array */
4543         pmc_pmcdisp = malloc(sizeof(enum pmc_mode) * md->pmd_npmc,
4544             M_PMC, M_WAITOK|M_ZERO);
4545
4546         KASSERT(pmc_pmcdisp != NULL,
4547             ("[pmc,%d] pmcdisp allocation returned NULL", __LINE__));
4548
4549         /* mark all PMCs as available */
4550         for (n = 0; n < (int) md->pmd_npmc; n++)
4551                 PMC_MARK_ROW_FREE(n);
4552
4553         /* allocate thread hash tables */
4554         pmc_ownerhash = hashinit(pmc_hashsize, M_PMC,
4555             &pmc_ownerhashmask);
4556
4557         pmc_processhash = hashinit(pmc_hashsize, M_PMC,
4558             &pmc_processhashmask);
4559         mtx_init(&pmc_processhash_mtx, "pmc-process-hash", "pmc-leaf",
4560             MTX_SPIN);
4561
4562         LIST_INIT(&pmc_ss_owners);
4563         pmc_ss_count = 0;
4564
4565         /* allocate a pool of spin mutexes */
4566         pmc_mtxpool = mtx_pool_create("pmc-leaf", pmc_mtxpool_size,
4567             MTX_SPIN);
4568
4569         PMCDBG(MOD,INI,1, "pmc_ownerhash=%p, mask=0x%lx "
4570             "targethash=%p mask=0x%lx", pmc_ownerhash, pmc_ownerhashmask,
4571             pmc_processhash, pmc_processhashmask);
4572
4573         /* register process {exit,fork,exec} handlers */
4574         pmc_exit_tag = EVENTHANDLER_REGISTER(process_exit,
4575             pmc_process_exit, NULL, EVENTHANDLER_PRI_ANY);
4576         pmc_fork_tag = EVENTHANDLER_REGISTER(process_fork,
4577             pmc_process_fork, NULL, EVENTHANDLER_PRI_ANY);
4578
4579         /* initialize logging */
4580         pmclog_initialize();
4581
4582         /* set hook functions */
4583         pmc_intr = md->pmd_intr;
4584         pmc_hook = pmc_hook_handler;
4585
4586         if (error == 0) {
4587                 printf(PMC_MODULE_NAME ":");
4588                 for (n = 0; n < (int) md->pmd_nclass; n++) {
4589                         pcd = &md->pmd_classdep[n];
4590                         printf(" %s/%d/%d/0x%b",
4591                             pmc_name_of_pmcclass[pcd->pcd_class],
4592                             pcd->pcd_num,
4593                             pcd->pcd_width,
4594                             pcd->pcd_caps,
4595                             "\20"
4596                             "\1INT\2USR\3SYS\4EDG\5THR"
4597                             "\6REA\7WRI\10INV\11QUA\12PRC"
4598                             "\13TAG\14CSC");
4599                 }
4600                 printf("\n");
4601         }
4602
4603         return (error);
4604 }
4605
4606 /* prepare to be unloaded */
4607 static void
4608 pmc_cleanup(void)
4609 {
4610         int c, cpu;
4611         unsigned int maxcpu;
4612         struct pmc_ownerhash *ph;
4613         struct pmc_owner *po, *tmp;
4614         struct pmc_binding pb;
4615 #ifdef  DEBUG
4616         struct pmc_processhash *prh;
4617 #endif
4618
4619         PMCDBG(MOD,INI,0, "%s", "cleanup");
4620
4621         /* switch off sampling */
4622         atomic_store_rel_int(&pmc_cpumask, 0);
4623         pmc_intr = NULL;
4624
4625         sx_xlock(&pmc_sx);
4626         if (pmc_hook == NULL) { /* being unloaded already */
4627                 sx_xunlock(&pmc_sx);
4628                 return;
4629         }
4630
4631         pmc_hook = NULL; /* prevent new threads from entering module */
4632
4633         /* deregister event handlers */
4634         EVENTHANDLER_DEREGISTER(process_fork, pmc_fork_tag);
4635         EVENTHANDLER_DEREGISTER(process_exit, pmc_exit_tag);
4636
4637         /* send SIGBUS to all owner threads, free up allocations */
4638         if (pmc_ownerhash)
4639                 for (ph = pmc_ownerhash;
4640                      ph <= &pmc_ownerhash[pmc_ownerhashmask];
4641                      ph++) {
4642                         LIST_FOREACH_SAFE(po, ph, po_next, tmp) {
4643                                 pmc_remove_owner(po);
4644
4645                                 /* send SIGBUS to owner processes */
4646                                 PMCDBG(MOD,INI,2, "cleanup signal proc=%p "
4647                                     "(%d, %s)", po->po_owner,
4648                                     po->po_owner->p_pid,
4649                                     po->po_owner->p_comm);
4650
4651                                 PROC_LOCK(po->po_owner);
4652                                 psignal(po->po_owner, SIGBUS);
4653                                 PROC_UNLOCK(po->po_owner);
4654
4655                                 pmc_destroy_owner_descriptor(po);
4656                         }
4657                 }
4658
4659         /* reclaim allocated data structures */
4660         if (pmc_mtxpool)
4661                 mtx_pool_destroy(&pmc_mtxpool);
4662
4663         mtx_destroy(&pmc_processhash_mtx);
4664         if (pmc_processhash) {
4665 #ifdef  DEBUG
4666                 struct pmc_process *pp;
4667
4668                 PMCDBG(MOD,INI,3, "%s", "destroy process hash");
4669                 for (prh = pmc_processhash;
4670                      prh <= &pmc_processhash[pmc_processhashmask];
4671                      prh++)
4672                         LIST_FOREACH(pp, prh, pp_next)
4673                             PMCDBG(MOD,INI,3, "pid=%d", pp->pp_proc->p_pid);
4674 #endif
4675
4676                 hashdestroy(pmc_processhash, M_PMC, pmc_processhashmask);
4677                 pmc_processhash = NULL;
4678         }
4679
4680         if (pmc_ownerhash) {
4681                 PMCDBG(MOD,INI,3, "%s", "destroy owner hash");
4682                 hashdestroy(pmc_ownerhash, M_PMC, pmc_ownerhashmask);
4683                 pmc_ownerhash = NULL;
4684         }
4685
4686         KASSERT(LIST_EMPTY(&pmc_ss_owners),
4687             ("[pmc,%d] Global SS owner list not empty", __LINE__));
4688         KASSERT(pmc_ss_count == 0,
4689             ("[pmc,%d] Global SS count not empty", __LINE__));
4690
4691         /* do processor and pmc-class dependent cleanup */
4692         maxcpu = pmc_cpu_max();
4693
4694         PMCDBG(MOD,INI,3, "%s", "md cleanup");
4695         if (md) {
4696                 pmc_save_cpu_binding(&pb);
4697                 for (cpu = 0; cpu < maxcpu; cpu++) {
4698                         PMCDBG(MOD,INI,1,"pmc-cleanup cpu=%d pcs=%p",
4699                             cpu, pmc_pcpu[cpu]);
4700                         if (!pmc_cpu_is_active(cpu) || pmc_pcpu[cpu] == NULL)
4701                                 continue;
4702                         pmc_select_cpu(cpu);
4703                         for (c = 0; c < md->pmd_nclass; c++)
4704                                 md->pmd_classdep[c].pcd_pcpu_fini(md, cpu);
4705                         if (md->pmd_pcpu_fini)
4706                                 md->pmd_pcpu_fini(md, cpu);
4707                 }
4708
4709                 pmc_md_finalize(md);
4710
4711                 free(md, M_PMC);
4712                 md = NULL;
4713                 pmc_restore_cpu_binding(&pb);
4714         }
4715
4716         /* Free per-cpu descriptors. */
4717         for (cpu = 0; cpu < maxcpu; cpu++) {
4718                 if (!pmc_cpu_is_active(cpu))
4719                         continue;
4720                 KASSERT(pmc_pcpu[cpu]->pc_sb != NULL,
4721                     ("[pmc,%d] Null cpu sample buffer cpu=%d", __LINE__,
4722                         cpu));
4723                 free(pmc_pcpu[cpu]->pc_sb->ps_callchains, M_PMC);
4724                 free(pmc_pcpu[cpu]->pc_sb, M_PMC);
4725                 free(pmc_pcpu[cpu], M_PMC);
4726         }
4727
4728         free(pmc_pcpu, M_PMC);
4729         pmc_pcpu = NULL;
4730
4731         free(pmc_pcpu_saved, M_PMC);
4732         pmc_pcpu_saved = NULL;
4733
4734         if (pmc_pmcdisp) {
4735                 free(pmc_pmcdisp, M_PMC);
4736                 pmc_pmcdisp = NULL;
4737         }
4738
4739         if (pmc_rowindex_to_classdep) {
4740                 free(pmc_rowindex_to_classdep, M_PMC);
4741                 pmc_rowindex_to_classdep = NULL;
4742         }
4743
4744         pmclog_shutdown();
4745
4746         sx_xunlock(&pmc_sx);    /* we are done */
4747 }
4748
4749 /*
4750  * The function called at load/unload.
4751  */
4752
4753 static int
4754 load (struct module *module __unused, int cmd, void *arg __unused)
4755 {
4756         int error;
4757
4758         error = 0;
4759
4760         switch (cmd) {
4761         case MOD_LOAD :
4762                 /* initialize the subsystem */
4763                 error = pmc_initialize();
4764                 if (error != 0)
4765                         break;
4766                 PMCDBG(MOD,INI,1, "syscall=%d maxcpu=%d",
4767                     pmc_syscall_num, pmc_cpu_max());
4768                 break;
4769
4770
4771         case MOD_UNLOAD :
4772         case MOD_SHUTDOWN:
4773                 pmc_cleanup();
4774                 PMCDBG(MOD,INI,1, "%s", "unloaded");
4775                 break;
4776
4777         default :
4778                 error = EINVAL; /* XXX should panic(9) */
4779                 break;
4780         }
4781
4782         return error;
4783 }
4784
4785 /* memory pool */
4786 MALLOC_DEFINE(M_PMC, "pmc", "Memory space for the PMC module");