sys/dev/hwpmc/hwpmc_mod.c

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