sys/dev/hwpmc/hwpmc_mod.c

   1 /*-
   2  * Copyright (c) 2003-2006 Joseph Koshy
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD$");
  30
  31 #include <sys/param.h>
  32 #include <sys/eventhandler.h>
  33 #include <sys/jail.h>
  34 #include <sys/kernel.h>
  35 #include <sys/kthread.h>
  36 #include <sys/limits.h>
  37 #include <sys/lock.h>
  38 #include <sys/malloc.h>
  39 #include <sys/module.h>
  40 #include <sys/mutex.h>
  41 #include <sys/pmc.h>
  42 #include <sys/pmckern.h>
  43 #include <sys/pmclog.h>
  44 #include <sys/priv.h>
  45 #include <sys/proc.h>
  46 #include <sys/queue.h>
  47 #include <sys/resourcevar.h>
  48 #include <sys/sched.h>
  49 #include <sys/signalvar.h>
  50 #include <sys/smp.h>
  51 #include <sys/sx.h>
  52 #include <sys/sysctl.h>
  53 #include <sys/sysent.h>
  54 #include <sys/systm.h>
  55 #include <sys/vnode.h>
  56
  57 #include <sys/linker.h>         /* needs to be after <sys/malloc.h> */
  58
  59 #include <machine/atomic.h>
  60 #include <machine/md_var.h>
  61
  62 /*
  63  * Types
  64  */
  65
  66 enum pmc_flags {
  67         PMC_FLAG_NONE     = 0x00, /* do nothing */
  68         PMC_FLAG_REMOVE   = 0x01, /* atomically remove entry from hash */
  69         PMC_FLAG_ALLOCATE = 0x02, /* add entry to hash if not found */
  70 };
  71
  72 /*
  73  * The offset in sysent where the syscall is allocated.
  74  */
  75
  76 static int pmc_syscall_num = NO_SYSCALL;
  77 struct pmc_cpu          **pmc_pcpu;      /* per-cpu state */
  78 pmc_value_t             *pmc_pcpu_saved; /* saved PMC values: CSW handling */
  79
  80 #define PMC_PCPU_SAVED(C,R)     pmc_pcpu_saved[(R) + md->pmd_npmc*(C)]
  81
  82 struct mtx_pool         *pmc_mtxpool;
  83 static int              *pmc_pmcdisp;    /* PMC row dispositions */
  84
  85 #define PMC_ROW_DISP_IS_FREE(R)         (pmc_pmcdisp[(R)] == 0)
  86 #define PMC_ROW_DISP_IS_THREAD(R)       (pmc_pmcdisp[(R)] > 0)
  87 #define PMC_ROW_DISP_IS_STANDALONE(R)   (pmc_pmcdisp[(R)] < 0)
  88
  89 #define PMC_MARK_ROW_FREE(R) do {                                         \
  90         pmc_pmcdisp[(R)] = 0;                                             \
  91 } while (0)
  92
  93 #define PMC_MARK_ROW_STANDALONE(R) do {                                   \
  94         KASSERT(pmc_pmcdisp[(R)] <= 0, ("[pmc,%d] row disposition error", \
  95                     __LINE__));                                           \
  96         atomic_add_int(&pmc_pmcdisp[(R)], -1);                            \
  97         KASSERT(pmc_pmcdisp[(R)] >= (-mp_ncpus), ("[pmc,%d] row "         \
  98                 "disposition error", __LINE__));                          \
  99 } while (0)
 100
 101 #define PMC_UNMARK_ROW_STANDALONE(R) do {                                 \
 102         atomic_add_int(&pmc_pmcdisp[(R)], 1);                             \
 103         KASSERT(pmc_pmcdisp[(R)] <= 0, ("[pmc,%d] row disposition error", \
 104                     __LINE__));                                           \
 105 } while (0)
 106
 107 #define PMC_MARK_ROW_THREAD(R) do {                                       \
 108         KASSERT(pmc_pmcdisp[(R)] >= 0, ("[pmc,%d] row disposition error", \
 109                     __LINE__));                                           \
 110         atomic_add_int(&pmc_pmcdisp[(R)], 1);                             \
 111 } while (0)
 112
 113 #define PMC_UNMARK_ROW_THREAD(R) do {                                     \
 114         atomic_add_int(&pmc_pmcdisp[(R)], -1);                            \
 115         KASSERT(pmc_pmcdisp[(R)] >= 0, ("[pmc,%d] row disposition error", \
 116                     __LINE__));                                           \
 117 } while (0)
 118
 119
 120 /* various event handlers */
 121 static eventhandler_tag pmc_exit_tag, pmc_fork_tag;
 122
 123 /* Module statistics */
 124 struct pmc_op_getdriverstats pmc_stats;
 125
 126 /* Machine/processor dependent operations */
 127 struct pmc_mdep  *md;
 128
 129 /*
 130  * Hash tables mapping owner processes and target threads to PMCs.
 131  */
 132
 133 struct mtx pmc_processhash_mtx;         /* spin mutex */
 134 static u_long pmc_processhashmask;
 135 static LIST_HEAD(pmc_processhash, pmc_process)  *pmc_processhash;
 136
 137 /*
 138  * Hash table of PMC owner descriptors.  This table is protected by
 139  * the shared PMC "sx" lock.
 140  */
 141
 142 static u_long pmc_ownerhashmask;
 143 static LIST_HEAD(pmc_ownerhash, pmc_owner)      *pmc_ownerhash;
 144
 145 /*
 146  * List of PMC owners with system-wide sampling PMCs.
 147  */
 148
 149 static LIST_HEAD(, pmc_owner)                   pmc_ss_owners;
 150
 151
 152 /*
 153  * Prototypes
 154  */
 155
 156 #ifdef  DEBUG
 157 static int      pmc_debugflags_sysctl_handler(SYSCTL_HANDLER_ARGS);
 158 static int      pmc_debugflags_parse(char *newstr, char *fence);
 159 #endif
 160
 161 static int      load(struct module *module, int cmd, void *arg);
 162 static int      pmc_attach_process(struct proc *p, struct pmc *pm);
 163 static struct pmc *pmc_allocate_pmc_descriptor(void);
 164 static struct pmc_owner *pmc_allocate_owner_descriptor(struct proc *p);
 165 static int      pmc_attach_one_process(struct proc *p, struct pmc *pm);
 166 static int      pmc_can_allocate_rowindex(struct proc *p, unsigned int ri,
 167     int cpu);
 168 static int      pmc_can_attach(struct pmc *pm, struct proc *p);
 169 static void     pmc_cleanup(void);
 170 static int      pmc_detach_process(struct proc *p, struct pmc *pm);
 171 static int      pmc_detach_one_process(struct proc *p, struct pmc *pm,
 172     int flags);
 173 static void     pmc_destroy_owner_descriptor(struct pmc_owner *po);
 174 static struct pmc_owner *pmc_find_owner_descriptor(struct proc *p);
 175 static int      pmc_find_pmc(pmc_id_t pmcid, struct pmc **pm);
 176 static struct pmc *pmc_find_pmc_descriptor_in_process(struct pmc_owner *po,
 177     pmc_id_t pmc);
 178 static struct pmc_process *pmc_find_process_descriptor(struct proc *p,
 179     uint32_t mode);
 180 static void     pmc_force_context_switch(void);
 181 static void     pmc_link_target_process(struct pmc *pm,
 182     struct pmc_process *pp);
 183 static void     pmc_maybe_remove_owner(struct pmc_owner *po);
 184 static void     pmc_process_csw_in(struct thread *td);
 185 static void     pmc_process_csw_out(struct thread *td);
 186 static void     pmc_process_exit(void *arg, struct proc *p);
 187 static void     pmc_process_fork(void *arg, struct proc *p1,
 188     struct proc *p2, int n);
 189 static void     pmc_process_samples(int cpu);
 190 static void     pmc_release_pmc_descriptor(struct pmc *pmc);
 191 static void     pmc_remove_owner(struct pmc_owner *po);
 192 static void     pmc_remove_process_descriptor(struct pmc_process *pp);
 193 static void     pmc_restore_cpu_binding(struct pmc_binding *pb);
 194 static void     pmc_save_cpu_binding(struct pmc_binding *pb);
 195 static void     pmc_select_cpu(int cpu);
 196 static int      pmc_start(struct pmc *pm);
 197 static int      pmc_stop(struct pmc *pm);
 198 static int      pmc_syscall_handler(struct thread *td, void *syscall_args);
 199 static void     pmc_unlink_target_process(struct pmc *pmc,
 200     struct pmc_process *pp);
 201
 202 /*
 203  * Kernel tunables and sysctl(8) interface.
 204  */
 205
 206 SYSCTL_NODE(_kern, OID_AUTO, hwpmc, CTLFLAG_RW, 0, "HWPMC parameters");
 207
 208 #ifdef  DEBUG
 209 struct pmc_debugflags pmc_debugflags = PMC_DEBUG_DEFAULT_FLAGS;
 210 char    pmc_debugstr[PMC_DEBUG_STRSIZE];
 211 TUNABLE_STR(PMC_SYSCTL_NAME_PREFIX "debugflags", pmc_debugstr,
 212     sizeof(pmc_debugstr));
 213 SYSCTL_PROC(_kern_hwpmc, OID_AUTO, debugflags,
 214     CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_TUN,
 215     0, 0, pmc_debugflags_sysctl_handler, "A", "debug flags");
 216 #endif
 217
 218 /*
 219  * kern.hwpmc.hashrows -- determines the number of rows in the
 220  * of the hash table used to look up threads
 221  */
 222
 223 static int pmc_hashsize = PMC_HASH_SIZE;
 224 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "hashsize", &pmc_hashsize);
 225 SYSCTL_INT(_kern_hwpmc, OID_AUTO, hashsize, CTLFLAG_TUN|CTLFLAG_RD,
 226     &pmc_hashsize, 0, "rows in hash tables");
 227
 228 /*
 229  * kern.hwpmc.nsamples --- number of PC samples per CPU
 230  */
 231
 232 static int pmc_nsamples = PMC_NSAMPLES;
 233 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "nsamples", &pmc_nsamples);
 234 SYSCTL_INT(_kern_hwpmc, OID_AUTO, nsamples, CTLFLAG_TUN|CTLFLAG_RD,
 235     &pmc_nsamples, 0, "number of PC samples per CPU");
 236
 237 /*
 238  * kern.hwpmc.mtxpoolsize -- number of mutexes in the mutex pool.
 239  */
 240
 241 static int pmc_mtxpool_size = PMC_MTXPOOL_SIZE;
 242 TUNABLE_INT(PMC_SYSCTL_NAME_PREFIX "mtxpoolsize", &pmc_mtxpool_size);
 243 SYSCTL_INT(_kern_hwpmc, OID_AUTO, mtxpoolsize, CTLFLAG_TUN|CTLFLAG_RD,
 244     &pmc_mtxpool_size, 0, "size of spin mutex pool");
 245
 246
 247 /*
 248  * security.bsd.unprivileged_syspmcs -- allow non-root processes to
 249  * allocate system-wide PMCs.
 250  *
 251  * Allowing unprivileged processes to allocate system PMCs is convenient
 252  * if system-wide measurements need to be taken concurrently with other
 253  * per-process measurements.  This feature is turned off by default.
 254  */
 255
 256 static int pmc_unprivileged_syspmcs = 0;
 257 TUNABLE_INT("security.bsd.unprivileged_syspmcs", &pmc_unprivileged_syspmcs);
 258 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_syspmcs, CTLFLAG_RW,
 259     &pmc_unprivileged_syspmcs, 0,
 260     "allow unprivileged process to allocate system PMCs");
 261
 262 /*
 263  * Hash function.  Discard the lower 2 bits of the pointer since
 264  * these are always zero for our uses.  The hash multiplier is
 265  * round((2^LONG_BIT) * ((sqrt(5)-1)/2)).
 266  */
 267
 268 #if     LONG_BIT == 64
 269 #define _PMC_HM         11400714819323198486u
 270 #elif   LONG_BIT == 32
 271 #define _PMC_HM         2654435769u
 272 #else
 273 #error  Must know the size of 'long' to compile
 274 #endif
 275
 276 #define PMC_HASH_PTR(P,M)       ((((unsigned long) (P) >> 2) * _PMC_HM) & (M))
 277
 278 /*
 279  * Syscall structures
 280  */
 281
 282 /* The `sysent' for the new syscall */
 283 static struct sysent pmc_sysent = {
 284         2,                      /* sy_narg */
 285         pmc_syscall_handler     /* sy_call */
 286 };
 287
 288 static struct syscall_module_data pmc_syscall_mod = {
 289         load,
 290         NULL,
 291         &pmc_syscall_num,
 292         &pmc_sysent,
 293         { 0, NULL }
 294 };
 295
 296 static moduledata_t pmc_mod = {
 297         PMC_MODULE_NAME,
 298         syscall_module_handler,
 299         &pmc_syscall_mod
 300 };
 301
 302 DECLARE_MODULE(pmc, pmc_mod, SI_SUB_SMP, SI_ORDER_ANY);
 303 MODULE_VERSION(pmc, PMC_VERSION);
 304
 305 #ifdef  DEBUG
 306 enum pmc_dbgparse_state {
 307         PMCDS_WS,               /* in whitespace */
 308         PMCDS_MAJOR,            /* seen a major keyword */
 309         PMCDS_MINOR
 310 };
 311
 312 static int
 313 pmc_debugflags_parse(char *newstr, char *fence)
 314 {
 315         char c, *p, *q;
 316         struct pmc_debugflags *tmpflags;
 317         int error, found, *newbits, tmp;
 318         size_t kwlen;
 319
 320         MALLOC(tmpflags, struct pmc_debugflags *, sizeof(*tmpflags),
 321             M_PMC, M_WAITOK|M_ZERO);
 322
 323         p = newstr;
 324         error = 0;
 325
 326         for (; p < fence && (c = *p); p++) {
 327
 328                 /* skip white space */
 329                 if (c == ' ' || c == '\t')
 330                         continue;
 331
 332                 /* look for a keyword followed by "=" */
 333                 for (q = p; p < fence && (c = *p) && c != '='; p++)
 334                         ;
 335                 if (c != '=') {
 336                         error = EINVAL;
 337                         goto done;
 338                 }
 339
 340                 kwlen = p - q;
 341                 newbits = NULL;
 342
 343                 /* lookup flag group name */
 344 #define DBG_SET_FLAG_MAJ(S,F)                                           \
 345                 if (kwlen == sizeof(S)-1 && strncmp(q, S, kwlen) == 0)  \
 346                         newbits = &tmpflags->pdb_ ## F;
 347
 348                 DBG_SET_FLAG_MAJ("cpu",         CPU);
 349                 DBG_SET_FLAG_MAJ("csw",         CSW);
 350                 DBG_SET_FLAG_MAJ("logging",     LOG);
 351                 DBG_SET_FLAG_MAJ("module",      MOD);
 352                 DBG_SET_FLAG_MAJ("md",          MDP);
 353                 DBG_SET_FLAG_MAJ("owner",       OWN);
 354                 DBG_SET_FLAG_MAJ("pmc",         PMC);
 355                 DBG_SET_FLAG_MAJ("process",     PRC);
 356                 DBG_SET_FLAG_MAJ("sampling",    SAM);
 357
 358                 if (newbits == NULL) {
 359                         error = EINVAL;
 360                         goto done;
 361                 }
 362
 363                 p++;            /* skip the '=' */
 364
 365                 /* Now parse the individual flags */
 366                 tmp = 0;
 367         newflag:
 368                 for (q = p; p < fence && (c = *p); p++)
 369                         if (c == ' ' || c == '\t' || c == ',')
 370                                 break;
 371
 372                 /* p == fence or c == ws or c == "," or c == 0 */
 373
 374                 if ((kwlen = p - q) == 0) {
 375                         *newbits = tmp;
 376                         continue;
 377                 }
 378
 379                 found = 0;
 380 #define DBG_SET_FLAG_MIN(S,F)                                           \
 381                 if (kwlen == sizeof(S)-1 && strncmp(q, S, kwlen) == 0)  \
 382                         tmp |= found = (1 << PMC_DEBUG_MIN_ ## F)
 383
 384                 /* a '*' denotes all possible flags in the group */
 385                 if (kwlen == 1 && *q == '*')
 386                         tmp = found = ~0;
 387                 /* look for individual flag names */
 388                 DBG_SET_FLAG_MIN("allocaterow", ALR);
 389                 DBG_SET_FLAG_MIN("allocate",    ALL);
 390                 DBG_SET_FLAG_MIN("attach",      ATT);
 391                 DBG_SET_FLAG_MIN("bind",        BND);
 392                 DBG_SET_FLAG_MIN("config",      CFG);
 393                 DBG_SET_FLAG_MIN("exec",        EXC);
 394                 DBG_SET_FLAG_MIN("exit",        EXT);
 395                 DBG_SET_FLAG_MIN("find",        FND);
 396                 DBG_SET_FLAG_MIN("flush",       FLS);
 397                 DBG_SET_FLAG_MIN("fork",        FRK);
 398                 DBG_SET_FLAG_MIN("getbuf",      GTB);
 399                 DBG_SET_FLAG_MIN("hook",        PMH);
 400                 DBG_SET_FLAG_MIN("init",        INI);
 401                 DBG_SET_FLAG_MIN("intr",        INT);
 402                 DBG_SET_FLAG_MIN("linktarget",  TLK);
 403                 DBG_SET_FLAG_MIN("mayberemove", OMR);
 404                 DBG_SET_FLAG_MIN("ops",         OPS);
 405                 DBG_SET_FLAG_MIN("read",        REA);
 406                 DBG_SET_FLAG_MIN("register",    REG);
 407                 DBG_SET_FLAG_MIN("release",     REL);
 408                 DBG_SET_FLAG_MIN("remove",      ORM);
 409                 DBG_SET_FLAG_MIN("sample",      SAM);
 410                 DBG_SET_FLAG_MIN("scheduleio",  SIO);
 411                 DBG_SET_FLAG_MIN("select",      SEL);
 412                 DBG_SET_FLAG_MIN("signal",      SIG);
 413                 DBG_SET_FLAG_MIN("swi",         SWI);
 414                 DBG_SET_FLAG_MIN("swo",         SWO);
 415                 DBG_SET_FLAG_MIN("start",       STA);
 416                 DBG_SET_FLAG_MIN("stop",        STO);
 417                 DBG_SET_FLAG_MIN("syscall",     PMS);
 418                 DBG_SET_FLAG_MIN("unlinktarget", TUL);
 419                 DBG_SET_FLAG_MIN("write",       WRI);
 420                 if (found == 0) {
 421                         /* unrecognized flag name */
 422                         error = EINVAL;
 423                         goto done;
 424                 }
 425
 426                 if (c == 0 || c == ' ' || c == '\t') {  /* end of flag group */
 427                         *newbits = tmp;
 428                         continue;
 429                 }
 430
 431                 p++;
 432                 goto newflag;
 433         }
 434
 435         /* save the new flag set */
 436         bcopy(tmpflags, &pmc_debugflags, sizeof(pmc_debugflags));
 437
 438  done:
 439         FREE(tmpflags, M_PMC);
 440         return error;
 441 }
 442
 443 static int
 444 pmc_debugflags_sysctl_handler(SYSCTL_HANDLER_ARGS)
 445 {
 446         char *fence, *newstr;
 447         int error;
 448         unsigned int n;
 449
 450         (void) arg1; (void) arg2; /* unused parameters */
 451
 452         n = sizeof(pmc_debugstr);
 453         MALLOC(newstr, char *, n, M_PMC, M_ZERO|M_WAITOK);
 454         (void) strlcpy(newstr, pmc_debugstr, n);
 455
 456         error = sysctl_handle_string(oidp, newstr, n, req);
 457
 458         /* if there is a new string, parse and copy it */
 459         if (error == 0 && req->newptr != NULL) {
 460                 fence = newstr + (n < req->newlen ? n : req->newlen + 1);
 461                 if ((error = pmc_debugflags_parse(newstr, fence)) == 0)
 462                         (void) strlcpy(pmc_debugstr, newstr,
 463                             sizeof(pmc_debugstr));
 464         }
 465
 466         FREE(newstr, M_PMC);
 467
 468         return error;
 469 }
 470 #endif
 471
 472 /*
 473  * Concurrency Control
 474  *
 475  * The driver manages the following data structures:
 476  *
 477  *   - target process descriptors, one per target process
 478  *   - owner process descriptors (and attached lists), one per owner process
 479  *   - lookup hash tables for owner and target processes
 480  *   - PMC descriptors (and attached lists)
 481  *   - per-cpu hardware state
 482  *   - the 'hook' variable through which the kernel calls into
 483  *     this module
 484  *   - the machine hardware state (managed by the MD layer)
 485  *
 486  * These data structures are accessed from:
 487  *
 488  * - thread context-switch code
 489  * - interrupt handlers (possibly on multiple cpus)
 490  * - kernel threads on multiple cpus running on behalf of user
 491  *   processes doing system calls
 492  * - this driver's private kernel threads
 493  *
 494  * = Locks and Locking strategy =
 495  *
 496  * The driver uses four locking strategies for its operation:
 497  *
 498  * - The global SX lock "pmc_sx" is used to protect internal
 499  *   data structures.
 500  *
 501  *   Calls into the module by syscall() start with this lock being
 502  *   held in exclusive mode.  Depending on the requested operation,
 503  *   the lock may be downgraded to 'shared' mode to allow more
 504  *   concurrent readers into the module.  Calls into the module from
 505  *   other parts of the kernel acquire the lock in shared mode.
 506  *
 507  *   This SX lock is held in exclusive mode for any operations that
 508  *   modify the linkages between the driver's internal data structures.
 509  *
 510  *   The 'pmc_hook' function pointer is also protected by this lock.
 511  *   It is only examined with the sx lock held in exclusive mode.  The
 512  *   kernel module is allowed to be unloaded only with the sx lock held
 513  *   in exclusive mode.  In normal syscall handling, after acquiring the
 514  *   pmc_sx lock we first check that 'pmc_hook' is non-null before
 515  *   proceeding.  This prevents races between the thread unloading the module
 516  *   and other threads seeking to use the module.
 517  *
 518  * - Lookups of target process structures and owner process structures
 519  *   cannot use the global "pmc_sx" SX lock because these lookups need
 520  *   to happen during context switches and in other critical sections
 521  *   where sleeping is not allowed.  We protect these lookup tables
 522  *   with their own private spin-mutexes, "pmc_processhash_mtx" and
 523  *   "pmc_ownerhash_mtx".
 524  *
 525  * - Interrupt handlers work in a lock free manner.  At interrupt
 526  *   time, handlers look at the PMC pointer (phw->phw_pmc) configured
 527  *   when the PMC was started.  If this pointer is NULL, the interrupt
 528  *   is ignored after updating driver statistics.  We ensure that this
 529  *   pointer is set (using an atomic operation if necessary) before the
 530  *   PMC hardware is started.  Conversely, this pointer is unset atomically
 531  *   only after the PMC hardware is stopped.
 532  *
 533  *   We ensure that everything needed for the operation of an
 534  *   interrupt handler is available without it needing to acquire any
 535  *   locks.  We also ensure that a PMC's software state is destroyed only
 536  *   after the PMC is taken off hardware (on all CPUs).
 537  *
 538  * - Context-switch handling with process-private PMCs needs more
 539  *   care.
 540  *
 541  *   A given process may be the target of multiple PMCs.  For example,
 542  *   PMCATTACH and PMCDETACH may be requested by a process on one CPU
 543  *   while the target process is running on another.  A PMC could also
 544  *   be getting released because its owner is exiting.  We tackle
 545  *   these situations in the following manner:
 546  *
 547  *   - each target process structure 'pmc_process' has an array
 548  *     of 'struct pmc *' pointers, one for each hardware PMC.
 549  *
 550  *   - At context switch IN time, each "target" PMC in RUNNING state
 551  *     gets started on hardware and a pointer to each PMC is copied into
 552  *     the per-cpu phw array.  The 'runcount' for the PMC is
 553  *     incremented.
 554  *
 555  *   - At context switch OUT time, all process-virtual PMCs are stopped
 556  *     on hardware.  The saved value is added to the PMCs value field
 557  *     only if the PMC is in a non-deleted state (the PMCs state could
 558  *     have changed during the current time slice).
 559  *
 560  *     Note that since in-between a switch IN on a processor and a switch
 561  *     OUT, the PMC could have been released on another CPU.  Therefore
 562  *     context switch OUT always looks at the hardware state to turn
 563  *     OFF PMCs and will update a PMC's saved value only if reachable
 564  *     from the target process record.
 565  *
 566  *   - OP PMCRELEASE could be called on a PMC at any time (the PMC could
 567  *     be attached to many processes at the time of the call and could
 568  *     be active on multiple CPUs).
 569  *
 570  *     We prevent further scheduling of the PMC by marking it as in
 571  *     state 'DELETED'.  If the runcount of the PMC is non-zero then
 572  *     this PMC is currently running on a CPU somewhere.  The thread
 573  *     doing the PMCRELEASE operation waits by repeatedly doing a
 574  *     pause() till the runcount comes to zero.
 575  *
 576  * The contents of a PMC descriptor (struct pmc) are protected using
 577  * a spin-mutex.  In order to save space, we use a mutex pool.
 578  *
 579  * In terms of lock types used by witness(4), we use:
 580  * - Type "pmc-sx", used by the global SX lock.
 581  * - Type "pmc-sleep", for sleep mutexes used by logger threads.
 582  * - Type "pmc-per-proc", for protecting PMC owner descriptors.
 583  * - Type "pmc-leaf", used for all other spin mutexes.
 584  */
 585
 586 /*
 587  * save the cpu binding of the current kthread
 588  */
 589
 590 static void
 591 pmc_save_cpu_binding(struct pmc_binding *pb)
 592 {
 593         PMCDBG(CPU,BND,2, "%s", "save-cpu");
 594         thread_lock(curthread);
 595         pb->pb_bound = sched_is_bound(curthread);
 596         pb->pb_cpu   = curthread->td_oncpu;
 597         thread_unlock(curthread);
 598         PMCDBG(CPU,BND,2, "save-cpu cpu=%d", pb->pb_cpu);
 599 }
 600
 601 /*
 602  * restore the cpu binding of the current thread
 603  */
 604
 605 static void
 606 pmc_restore_cpu_binding(struct pmc_binding *pb)
 607 {
 608         PMCDBG(CPU,BND,2, "restore-cpu curcpu=%d restore=%d",
 609             curthread->td_oncpu, pb->pb_cpu);
 610         thread_lock(curthread);
 611         if (pb->pb_bound)
 612                 sched_bind(curthread, pb->pb_cpu);
 613         else
 614                 sched_unbind(curthread);
 615         thread_unlock(curthread);
 616         PMCDBG(CPU,BND,2, "%s", "restore-cpu done");
 617 }
 618
 619 /*
 620  * move execution over the specified cpu and bind it there.
 621  */
 622
 623 static void
 624 pmc_select_cpu(int cpu)
 625 {
 626         KASSERT(cpu >= 0 && cpu < mp_ncpus,
 627             ("[pmc,%d] bad cpu number %d", __LINE__, cpu));
 628
 629         /* never move to a disabled CPU */
 630         KASSERT(pmc_cpu_is_disabled(cpu) == 0, ("[pmc,%d] selecting "
 631             "disabled CPU %d", __LINE__, cpu));
 632
 633         PMCDBG(CPU,SEL,2, "select-cpu cpu=%d", cpu);
 634         thread_lock(curthread);
 635         sched_bind(curthread, cpu);
 636         thread_unlock(curthread);
 637
 638         KASSERT(curthread->td_oncpu == cpu,
 639             ("[pmc,%d] CPU not bound [cpu=%d, curr=%d]", __LINE__,
 640                 cpu, curthread->td_oncpu));
 641
 642         PMCDBG(CPU,SEL,2, "select-cpu cpu=%d ok", cpu);
 643 }
 644
 645 /*
 646  * Force a context switch.
 647  *
 648  * We do this by pause'ing for 1 tick -- invoking mi_switch() is not
 649  * guaranteed to force a context switch.
 650  */
 651
 652 static void
 653 pmc_force_context_switch(void)
 654 {
 655
 656         pause("pmcctx", 1);
 657 }
 658
 659 /*
 660  * Get the file name for an executable.  This is a simple wrapper
 661  * around vn_fullpath(9).
 662  */
 663
 664 static void
 665 pmc_getfilename(struct vnode *v, char **fullpath, char **freepath)
 666 {
 667         struct thread *td;
 668
 669         td = curthread;
 670         *fullpath = "unknown";
 671         *freepath = NULL;
 672         vn_lock(v, LK_CANRECURSE | LK_EXCLUSIVE | LK_RETRY, td);
 673         vn_fullpath(td, v, fullpath, freepath);
 674         VOP_UNLOCK(v, 0, td);
 675 }
 676
 677 /*
 678  * remove an process owning PMCs
 679  */
 680
 681 void
 682 pmc_remove_owner(struct pmc_owner *po)
 683 {
 684         struct pmc *pm, *tmp;
 685
 686         sx_assert(&pmc_sx, SX_XLOCKED);
 687
 688         PMCDBG(OWN,ORM,1, "remove-owner po=%p", po);
 689
 690         /* Remove descriptor from the owner hash table */
 691         LIST_REMOVE(po, po_next);
 692
 693         /* release all owned PMC descriptors */
 694         LIST_FOREACH_SAFE(pm, &po->po_pmcs, pm_next, tmp) {
 695                 PMCDBG(OWN,ORM,2, "pmc=%p", pm);
 696                 KASSERT(pm->pm_owner == po,
 697                     ("[pmc,%d] owner %p != po %p", __LINE__, pm->pm_owner, po));
 698
 699                 pmc_release_pmc_descriptor(pm); /* will unlink from the list */
 700         }
 701
 702         KASSERT(po->po_sscount == 0,
 703             ("[pmc,%d] SS count not zero", __LINE__));
 704         KASSERT(LIST_EMPTY(&po->po_pmcs),
 705             ("[pmc,%d] PMC list not empty", __LINE__));
 706
 707         /* de-configure the log file if present */
 708         if (po->po_flags & PMC_PO_OWNS_LOGFILE)
 709                 pmclog_deconfigure_log(po);
 710 }
 711
 712 /*
 713  * remove an owner process record if all conditions are met.
 714  */
 715
 716 static void
 717 pmc_maybe_remove_owner(struct pmc_owner *po)
 718 {
 719
 720         PMCDBG(OWN,OMR,1, "maybe-remove-owner po=%p", po);
 721
 722         /*
 723          * Remove owner record if
 724          * - this process does not own any PMCs
 725          * - this process has not allocated a system-wide sampling buffer
 726          */
 727
 728         if (LIST_EMPTY(&po->po_pmcs) &&
 729             ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)) {
 730                 pmc_remove_owner(po);
 731                 pmc_destroy_owner_descriptor(po);
 732         }
 733 }
 734
 735 /*
 736  * Add an association between a target process and a PMC.
 737  */
 738
 739 static void
 740 pmc_link_target_process(struct pmc *pm, struct pmc_process *pp)
 741 {
 742         int ri;
 743         struct pmc_target *pt;
 744
 745         sx_assert(&pmc_sx, SX_XLOCKED);
 746
 747         KASSERT(pm != NULL && pp != NULL,
 748             ("[pmc,%d] Null pm %p or pp %p", __LINE__, pm, pp));
 749         KASSERT(PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)),
 750             ("[pmc,%d] Attaching a non-process-virtual pmc=%p to pid=%d",
 751                 __LINE__, pm, pp->pp_proc->p_pid));
 752         KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt < ((int) md->pmd_npmc - 1),
 753             ("[pmc,%d] Illegal reference count %d for process record %p",
 754                 __LINE__, pp->pp_refcnt, (void *) pp));
 755
 756         ri = PMC_TO_ROWINDEX(pm);
 757
 758         PMCDBG(PRC,TLK,1, "link-target pmc=%p ri=%d pmc-process=%p",
 759             pm, ri, pp);
 760
 761 #ifdef  DEBUG
 762         LIST_FOREACH(pt, &pm->pm_targets, pt_next)
 763             if (pt->pt_process == pp)
 764                     KASSERT(0, ("[pmc,%d] pp %p already in pmc %p targets",
 765                                 __LINE__, pp, pm));
 766 #endif
 767
 768         MALLOC(pt, struct pmc_target *, sizeof(struct pmc_target),
 769             M_PMC, M_ZERO|M_WAITOK);
 770
 771         pt->pt_process = pp;
 772
 773         LIST_INSERT_HEAD(&pm->pm_targets, pt, pt_next);
 774
 775         atomic_store_rel_ptr((uintptr_t *)&pp->pp_pmcs[ri].pp_pmc,
 776             (uintptr_t)pm);
 777
 778         if (pm->pm_owner->po_owner == pp->pp_proc)
 779                 pm->pm_flags |= PMC_F_ATTACHED_TO_OWNER;
 780
 781         /*
 782          * Initialize the per-process values at this row index.
 783          */
 784         pp->pp_pmcs[ri].pp_pmcval = PMC_TO_MODE(pm) == PMC_MODE_TS ?
 785             pm->pm_sc.pm_reloadcount : 0;
 786
 787         pp->pp_refcnt++;
 788
 789 }
 790
 791 /*
 792  * Removes the association between a target process and a PMC.
 793  */
 794
 795 static void
 796 pmc_unlink_target_process(struct pmc *pm, struct pmc_process *pp)
 797 {
 798         int ri;
 799         struct proc *p;
 800         struct pmc_target *ptgt;
 801
 802         sx_assert(&pmc_sx, SX_XLOCKED);
 803
 804         KASSERT(pm != NULL && pp != NULL,
 805             ("[pmc,%d] Null pm %p or pp %p", __LINE__, pm, pp));
 806
 807         KASSERT(pp->pp_refcnt >= 1 && pp->pp_refcnt < (int) md->pmd_npmc,
 808             ("[pmc,%d] Illegal ref count %d on process record %p",
 809                 __LINE__, pp->pp_refcnt, (void *) pp));
 810
 811         ri = PMC_TO_ROWINDEX(pm);
 812
 813         PMCDBG(PRC,TUL,1, "unlink-target pmc=%p ri=%d pmc-process=%p",
 814             pm, ri, pp);
 815
 816         KASSERT(pp->pp_pmcs[ri].pp_pmc == pm,
 817             ("[pmc,%d] PMC ri %d mismatch pmc %p pp->[ri] %p", __LINE__,
 818                 ri, pm, pp->pp_pmcs[ri].pp_pmc));
 819
 820         pp->pp_pmcs[ri].pp_pmc = NULL;
 821         pp->pp_pmcs[ri].pp_pmcval = (pmc_value_t) 0;
 822
 823         /* Remove owner-specific flags */
 824         if (pm->pm_owner->po_owner == pp->pp_proc) {
 825                 pp->pp_flags &= ~PMC_PP_ENABLE_MSR_ACCESS;
 826                 pm->pm_flags &= ~PMC_F_ATTACHED_TO_OWNER;
 827         }
 828
 829         pp->pp_refcnt--;
 830
 831         /* Remove the target process from the PMC structure */
 832         LIST_FOREACH(ptgt, &pm->pm_targets, pt_next)
 833                 if (ptgt->pt_process == pp)
 834                         break;
 835
 836         KASSERT(ptgt != NULL, ("[pmc,%d] process %p (pp: %p) not found "
 837                     "in pmc %p", __LINE__, pp->pp_proc, pp, pm));
 838
 839         LIST_REMOVE(ptgt, pt_next);
 840         FREE(ptgt, M_PMC);
 841
 842         /* if the PMC now lacks targets, send the owner a SIGIO */
 843         if (LIST_EMPTY(&pm->pm_targets)) {
 844                 p = pm->pm_owner->po_owner;
 845                 PROC_LOCK(p);
 846                 psignal(p, SIGIO);
 847                 PROC_UNLOCK(p);
 848
 849                 PMCDBG(PRC,SIG,2, "signalling proc=%p signal=%d", p,
 850                     SIGIO);
 851         }
 852 }
 853
 854 /*
 855  * Check if PMC 'pm' may be attached to target process 't'.
 856  */
 857
 858 static int
 859 pmc_can_attach(struct pmc *pm, struct proc *t)
 860 {
 861         struct proc *o;         /* pmc owner */
 862         struct ucred *oc, *tc;  /* owner, target credentials */
 863         int decline_attach, i;
 864
 865         /*
 866          * A PMC's owner can always attach that PMC to itself.
 867          */
 868
 869         if ((o = pm->pm_owner->po_owner) == t)
 870                 return 0;
 871
 872         PROC_LOCK(o);
 873         oc = o->p_ucred;
 874         crhold(oc);
 875         PROC_UNLOCK(o);
 876
 877         PROC_LOCK(t);
 878         tc = t->p_ucred;
 879         crhold(tc);
 880         PROC_UNLOCK(t);
 881
 882         /*
 883          * The effective uid of the PMC owner should match at least one
 884          * of the {effective,real,saved} uids of the target process.
 885          */
 886
 887         decline_attach = oc->cr_uid != tc->cr_uid &&
 888             oc->cr_uid != tc->cr_svuid &&
 889             oc->cr_uid != tc->cr_ruid;
 890
 891         /*
 892          * Every one of the target's group ids, must be in the owner's
 893          * group list.
 894          */
 895         for (i = 0; !decline_attach && i < tc->cr_ngroups; i++)
 896                 decline_attach = !groupmember(tc->cr_groups[i], oc);
 897
 898         /* check the read and saved gids too */
 899         if (decline_attach == 0)
 900                 decline_attach = !groupmember(tc->cr_rgid, oc) ||
 901                     !groupmember(tc->cr_svgid, oc);
 902
 903         crfree(tc);
 904         crfree(oc);
 905
 906         return !decline_attach;
 907 }
 908
 909 /*
 910  * Attach a process to a PMC.
 911  */
 912
 913 static int
 914 pmc_attach_one_process(struct proc *p, struct pmc *pm)
 915 {
 916         int ri;
 917         char *fullpath, *freepath;
 918         struct pmc_process      *pp;
 919
 920         sx_assert(&pmc_sx, SX_XLOCKED);
 921
 922         PMCDBG(PRC,ATT,2, "attach-one pm=%p ri=%d proc=%p (%d, %s)", pm,
 923             PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
 924
 925         /*
 926          * Locate the process descriptor corresponding to process 'p',
 927          * allocating space as needed.
 928          *
 929          * Verify that rowindex 'pm_rowindex' is free in the process
 930          * descriptor.
 931          *
 932          * If not, allocate space for a descriptor and link the
 933          * process descriptor and PMC.
 934          */
 935         ri = PMC_TO_ROWINDEX(pm);
 936
 937         if ((pp = pmc_find_process_descriptor(p, PMC_FLAG_ALLOCATE)) == NULL)
 938                 return ENOMEM;
 939
 940         if (pp->pp_pmcs[ri].pp_pmc == pm) /* already present at slot [ri] */
 941                 return EEXIST;
 942
 943         if (pp->pp_pmcs[ri].pp_pmc != NULL)
 944                 return EBUSY;
 945
 946         pmc_link_target_process(pm, pp);
 947
 948         if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)) &&
 949             (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) == 0)
 950                 pm->pm_flags |= PMC_F_NEEDS_LOGFILE;
 951
 952         pm->pm_flags |= PMC_F_ATTACH_DONE; /* mark as attached */
 953
 954         /* issue an attach event to a configured log file */
 955         if (pm->pm_owner->po_flags & PMC_PO_OWNS_LOGFILE) {
 956                 pmc_getfilename(p->p_textvp, &fullpath, &freepath);
 957                 pmclog_process_pmcattach(pm, p->p_pid, fullpath);
 958                 if (freepath)
 959                         FREE(freepath, M_TEMP);
 960         }
 961         /* mark process as using HWPMCs */
 962         PROC_LOCK(p);
 963         p->p_flag |= P_HWPMC;
 964         PROC_UNLOCK(p);
 965
 966         return 0;
 967 }
 968
 969 /*
 970  * Attach a process and optionally its children
 971  */
 972
 973 static int
 974 pmc_attach_process(struct proc *p, struct pmc *pm)
 975 {
 976         int error;
 977         struct proc *top;
 978
 979         sx_assert(&pmc_sx, SX_XLOCKED);
 980
 981         PMCDBG(PRC,ATT,1, "attach pm=%p ri=%d proc=%p (%d, %s)", pm,
 982             PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
 983
 984
 985         /*
 986          * If this PMC successfully allowed a GETMSR operation
 987          * in the past, disallow further ATTACHes.
 988          */
 989
 990         if ((pm->pm_flags & PMC_PP_ENABLE_MSR_ACCESS) != 0)
 991                 return EPERM;
 992
 993         if ((pm->pm_flags & PMC_F_DESCENDANTS) == 0)
 994                 return pmc_attach_one_process(p, pm);
 995
 996         /*
 997          * Traverse all child processes, attaching them to
 998          * this PMC.
 999          */
1000
1001         sx_slock(&proctree_lock);
1002
1003         top = p;
1004
1005         for (;;) {
1006                 if ((error = pmc_attach_one_process(p, pm)) != 0)
1007                         break;
1008                 if (!LIST_EMPTY(&p->p_children))
1009                         p = LIST_FIRST(&p->p_children);
1010                 else for (;;) {
1011                         if (p == top)
1012                                 goto done;
1013                         if (LIST_NEXT(p, p_sibling)) {
1014                                 p = LIST_NEXT(p, p_sibling);
1015                                 break;
1016                         }
1017                         p = p->p_pptr;
1018                 }
1019         }
1020
1021         if (error)
1022                 (void) pmc_detach_process(top, pm);
1023
1024  done:
1025         sx_sunlock(&proctree_lock);
1026         return error;
1027 }
1028
1029 /*
1030  * Detach a process from a PMC.  If there are no other PMCs tracking
1031  * this process, remove the process structure from its hash table.  If
1032  * 'flags' contains PMC_FLAG_REMOVE, then free the process structure.
1033  */
1034
1035 static int
1036 pmc_detach_one_process(struct proc *p, struct pmc *pm, int flags)
1037 {
1038         int ri;
1039         struct pmc_process *pp;
1040
1041         sx_assert(&pmc_sx, SX_XLOCKED);
1042
1043         KASSERT(pm != NULL,
1044             ("[pmc,%d] null pm pointer", __LINE__));
1045
1046         ri = PMC_TO_ROWINDEX(pm);
1047
1048         PMCDBG(PRC,ATT,2, "detach-one pm=%p ri=%d proc=%p (%d, %s) flags=0x%x",
1049             pm, ri, p, p->p_pid, p->p_comm, flags);
1050
1051         if ((pp = pmc_find_process_descriptor(p, 0)) == NULL)
1052                 return ESRCH;
1053
1054         if (pp->pp_pmcs[ri].pp_pmc != pm)
1055                 return EINVAL;
1056
1057         pmc_unlink_target_process(pm, pp);
1058
1059         /* Issue a detach entry if a log file is configured */
1060         if (pm->pm_owner->po_flags & PMC_PO_OWNS_LOGFILE)
1061                 pmclog_process_pmcdetach(pm, p->p_pid);
1062
1063         /*
1064          * If there are no PMCs targetting this process, we remove its
1065          * descriptor from the target hash table and unset the P_HWPMC
1066          * flag in the struct proc.
1067          */
1068         KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt < (int) md->pmd_npmc,
1069             ("[pmc,%d] Illegal refcnt %d for process struct %p",
1070                 __LINE__, pp->pp_refcnt, pp));
1071
1072         if (pp->pp_refcnt != 0) /* still a target of some PMC */
1073                 return 0;
1074
1075         pmc_remove_process_descriptor(pp);
1076
1077         if (flags & PMC_FLAG_REMOVE)
1078                 FREE(pp, M_PMC);
1079
1080         PROC_LOCK(p);
1081         p->p_flag &= ~P_HWPMC;
1082         PROC_UNLOCK(p);
1083
1084         return 0;
1085 }
1086
1087 /*
1088  * Detach a process and optionally its descendants from a PMC.
1089  */
1090
1091 static int
1092 pmc_detach_process(struct proc *p, struct pmc *pm)
1093 {
1094         struct proc *top;
1095
1096         sx_assert(&pmc_sx, SX_XLOCKED);
1097
1098         PMCDBG(PRC,ATT,1, "detach pm=%p ri=%d proc=%p (%d, %s)", pm,
1099             PMC_TO_ROWINDEX(pm), p, p->p_pid, p->p_comm);
1100
1101         if ((pm->pm_flags & PMC_F_DESCENDANTS) == 0)
1102                 return pmc_detach_one_process(p, pm, PMC_FLAG_REMOVE);
1103
1104         /*
1105          * Traverse all children, detaching them from this PMC.  We
1106          * ignore errors since we could be detaching a PMC from a
1107          * partially attached proc tree.
1108          */
1109
1110         sx_slock(&proctree_lock);
1111
1112         top = p;
1113
1114         for (;;) {
1115                 (void) pmc_detach_one_process(p, pm, PMC_FLAG_REMOVE);
1116
1117                 if (!LIST_EMPTY(&p->p_children))
1118                         p = LIST_FIRST(&p->p_children);
1119                 else for (;;) {
1120                         if (p == top)
1121                                 goto done;
1122                         if (LIST_NEXT(p, p_sibling)) {
1123                                 p = LIST_NEXT(p, p_sibling);
1124                                 break;
1125                         }
1126                         p = p->p_pptr;
1127                 }
1128         }
1129
1130  done:
1131         sx_sunlock(&proctree_lock);
1132
1133         if (LIST_EMPTY(&pm->pm_targets))
1134                 pm->pm_flags &= ~PMC_F_ATTACH_DONE;
1135
1136         return 0;
1137 }
1138
1139
1140 /*
1141  * Thread context switch IN
1142  */
1143
1144 static void
1145 pmc_process_csw_in(struct thread *td)
1146 {
1147         int cpu;
1148         unsigned int ri;
1149         struct pmc *pm;
1150         struct proc *p;
1151         struct pmc_cpu *pc;
1152         struct pmc_hw *phw;
1153         struct pmc_process *pp;
1154         pmc_value_t newvalue;
1155
1156         p = td->td_proc;
1157
1158         if ((pp = pmc_find_process_descriptor(p, PMC_FLAG_NONE)) == NULL)
1159                 return;
1160
1161         KASSERT(pp->pp_proc == td->td_proc,
1162             ("[pmc,%d] not my thread state", __LINE__));
1163
1164         critical_enter(); /* no preemption from this point */
1165
1166         cpu = PCPU_GET(cpuid); /* td->td_oncpu is invalid */
1167
1168         PMCDBG(CSW,SWI,1, "cpu=%d proc=%p (%d, %s) pp=%p", cpu, p,
1169             p->p_pid, p->p_comm, pp);
1170
1171         KASSERT(cpu >= 0 && cpu < mp_ncpus,
1172             ("[pmc,%d] wierd CPU id %d", __LINE__, cpu));
1173
1174         pc = pmc_pcpu[cpu];
1175
1176         for (ri = 0; ri < md->pmd_npmc; ri++) {
1177
1178                 if ((pm = pp->pp_pmcs[ri].pp_pmc) == NULL)
1179                         continue;
1180
1181                 KASSERT(PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)),
1182                     ("[pmc,%d] Target PMC in non-virtual mode (%d)",
1183                         __LINE__, PMC_TO_MODE(pm)));
1184
1185                 KASSERT(PMC_TO_ROWINDEX(pm) == ri,
1186                     ("[pmc,%d] Row index mismatch pmc %d != ri %d",
1187                         __LINE__, PMC_TO_ROWINDEX(pm), ri));
1188
1189                 /*
1190                  * Only PMCs that are marked as 'RUNNING' need
1191                  * be placed on hardware.
1192                  */
1193
1194                 if (pm->pm_state != PMC_STATE_RUNNING)
1195                         continue;
1196
1197                 /* increment PMC runcount */
1198                 atomic_add_rel_32(&pm->pm_runcount, 1);
1199
1200                 /* configure the HWPMC we are going to use. */
1201                 md->pmd_config_pmc(cpu, ri, pm);
1202
1203                 phw = pc->pc_hwpmcs[ri];
1204
1205                 KASSERT(phw != NULL,
1206                     ("[pmc,%d] null hw pointer", __LINE__));
1207
1208                 KASSERT(phw->phw_pmc == pm,
1209                     ("[pmc,%d] hw->pmc %p != pmc %p", __LINE__,
1210                         phw->phw_pmc, pm));
1211
1212                 /*
1213                  * Write out saved value and start the PMC.
1214                  *
1215                  * Sampling PMCs use a per-process value, while
1216                  * counting mode PMCs use a per-pmc value that is
1217                  * inherited across descendants.
1218                  */
1219                 if (PMC_TO_MODE(pm) == PMC_MODE_TS) {
1220                         mtx_pool_lock_spin(pmc_mtxpool, pm);
1221                         newvalue = PMC_PCPU_SAVED(cpu,ri) =
1222                             pp->pp_pmcs[ri].pp_pmcval;
1223                         mtx_pool_unlock_spin(pmc_mtxpool, pm);
1224                 } else {
1225                         KASSERT(PMC_TO_MODE(pm) == PMC_MODE_TC,
1226                             ("[pmc,%d] illegal mode=%d", __LINE__,
1227                             PMC_TO_MODE(pm)));
1228                         mtx_pool_lock_spin(pmc_mtxpool, pm);
1229                         newvalue = PMC_PCPU_SAVED(cpu, ri) =
1230                             pm->pm_gv.pm_savedvalue;
1231                         mtx_pool_unlock_spin(pmc_mtxpool, pm);
1232                 }
1233
1234                 PMCDBG(CSW,SWI,1,"cpu=%d ri=%d new=%jd", cpu, ri, newvalue);
1235
1236                 md->pmd_write_pmc(cpu, ri, newvalue);
1237                 md->pmd_start_pmc(cpu, ri);
1238         }
1239
1240         /*
1241          * perform any other architecture/cpu dependent thread
1242          * switch-in actions.
1243          */
1244
1245         (void) (*md->pmd_switch_in)(pc, pp);
1246
1247         critical_exit();
1248
1249 }
1250
1251 /*
1252  * Thread context switch OUT.
1253  */
1254
1255 static void
1256 pmc_process_csw_out(struct thread *td)
1257 {
1258         int cpu;
1259         enum pmc_mode mode;
1260         unsigned int ri;
1261         struct pmc *pm;
1262         struct proc *p;
1263         struct pmc_cpu *pc;
1264         struct pmc_process *pp;
1265         int64_t tmp;
1266         pmc_value_t newvalue;
1267
1268         /*
1269          * Locate our process descriptor; this may be NULL if
1270          * this process is exiting and we have already removed
1271          * the process from the target process table.
1272          *
1273          * Note that due to kernel preemption, multiple
1274          * context switches may happen while the process is
1275          * exiting.
1276          *
1277          * Note also that if the target process cannot be
1278          * found we still need to deconfigure any PMCs that
1279          * are currently running on hardware.
1280          */
1281
1282         p = td->td_proc;
1283         pp = pmc_find_process_descriptor(p, PMC_FLAG_NONE);
1284
1285         /*
1286          * save PMCs
1287          */
1288
1289         critical_enter();
1290
1291         cpu = PCPU_GET(cpuid); /* td->td_oncpu is invalid */
1292
1293         PMCDBG(CSW,SWO,1, "cpu=%d proc=%p (%d, %s) pp=%p", cpu, p,
1294             p->p_pid, p->p_comm, pp);
1295
1296         KASSERT(cpu >= 0 && cpu < mp_ncpus,
1297             ("[pmc,%d wierd CPU id %d", __LINE__, cpu));
1298
1299         pc = pmc_pcpu[cpu];
1300
1301         /*
1302          * When a PMC gets unlinked from a target PMC, it will
1303          * be removed from the target's pp_pmc[] array.
1304          *
1305          * However, on a MP system, the target could have been
1306          * executing on another CPU at the time of the unlink.
1307          * So, at context switch OUT time, we need to look at
1308          * the hardware to determine if a PMC is scheduled on
1309          * it.
1310          */
1311
1312         for (ri = 0; ri < md->pmd_npmc; ri++) {
1313
1314                 pm = NULL;
1315                 (void) (*md->pmd_get_config)(cpu, ri, &pm);
1316
1317                 if (pm == NULL) /* nothing at this row index */
1318                         continue;
1319
1320                 mode = PMC_TO_MODE(pm);
1321                 if (!PMC_IS_VIRTUAL_MODE(mode))
1322                         continue; /* not a process virtual PMC */
1323
1324                 KASSERT(PMC_TO_ROWINDEX(pm) == ri,
1325                     ("[pmc,%d] ri mismatch pmc(%d) ri(%d)",
1326                         __LINE__, PMC_TO_ROWINDEX(pm), ri));
1327
1328                 /* Stop hardware if not already stopped */
1329                 if (pm->pm_stalled == 0)
1330                         md->pmd_stop_pmc(cpu, ri);
1331
1332                 /* reduce this PMC's runcount */
1333                 atomic_subtract_rel_32(&pm->pm_runcount, 1);
1334
1335                 /*
1336                  * If this PMC is associated with this process,
1337                  * save the reading.
1338                  */
1339
1340                 if (pp != NULL && pp->pp_pmcs[ri].pp_pmc != NULL) {
1341
1342                         KASSERT(pm == pp->pp_pmcs[ri].pp_pmc,
1343                             ("[pmc,%d] pm %p != pp_pmcs[%d] %p", __LINE__,
1344                                 pm, ri, pp->pp_pmcs[ri].pp_pmc));
1345
1346                         KASSERT(pp->pp_refcnt > 0,
1347                             ("[pmc,%d] pp refcnt = %d", __LINE__,
1348                                 pp->pp_refcnt));
1349
1350                         md->pmd_read_pmc(cpu, ri, &newvalue);
1351
1352                         tmp = newvalue - PMC_PCPU_SAVED(cpu,ri);
1353
1354                         PMCDBG(CSW,SWI,1,"cpu=%d ri=%d tmp=%jd", cpu, ri,
1355                             tmp);
1356
1357                         if (mode == PMC_MODE_TS) {
1358
1359                                 /*
1360                                  * For sampling process-virtual PMCs,
1361                                  * we expect the count to be
1362                                  * decreasing as the 'value'
1363                                  * programmed into the PMC is the
1364                                  * number of events to be seen till
1365                                  * the next sampling interrupt.
1366                                  */
1367                                 if (tmp < 0)
1368                                         tmp += pm->pm_sc.pm_reloadcount;
1369                                 mtx_pool_lock_spin(pmc_mtxpool, pm);
1370                                 pp->pp_pmcs[ri].pp_pmcval -= tmp;
1371                                 if ((int64_t) pp->pp_pmcs[ri].pp_pmcval < 0)
1372                                         pp->pp_pmcs[ri].pp_pmcval +=
1373                                             pm->pm_sc.pm_reloadcount;
1374                                 mtx_pool_unlock_spin(pmc_mtxpool, pm);
1375
1376                         } else {
1377
1378                                 /*
1379                                  * For counting process-virtual PMCs,
1380                                  * we expect the count to be
1381                                  * increasing monotonically, modulo a 64
1382                                  * bit wraparound.
1383                                  */
1384                                 KASSERT((int64_t) tmp >= 0,
1385                                     ("[pmc,%d] negative increment cpu=%d "
1386                                      "ri=%d newvalue=%jx saved=%jx "
1387                                      "incr=%jx", __LINE__, cpu, ri,
1388                                      newvalue, PMC_PCPU_SAVED(cpu,ri), tmp));
1389
1390                                 mtx_pool_lock_spin(pmc_mtxpool, pm);
1391                                 pm->pm_gv.pm_savedvalue += tmp;
1392                                 pp->pp_pmcs[ri].pp_pmcval += tmp;
1393                                 mtx_pool_unlock_spin(pmc_mtxpool, pm);
1394
1395                                 if (pm->pm_flags & PMC_F_LOG_PROCCSW)
1396                                         pmclog_process_proccsw(pm, pp, tmp);
1397                         }
1398                 }
1399
1400                 /* mark hardware as free */
1401                 md->pmd_config_pmc(cpu, ri, NULL);
1402         }
1403
1404         /*
1405          * perform any other architecture/cpu dependent thread
1406          * switch out functions.
1407          */
1408
1409         (void) (*md->pmd_switch_out)(pc, pp);
1410
1411         critical_exit();
1412 }
1413
1414 /*
1415  * Log a KLD operation.
1416  */
1417
1418 static void
1419 pmc_process_kld_load(struct pmckern_map_in *pkm)
1420 {
1421         struct pmc_owner *po;
1422
1423         sx_assert(&pmc_sx, SX_LOCKED);
1424
1425         /*
1426          * Notify owners of system sampling PMCs about KLD operations.
1427          */
1428
1429         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1430             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1431                 pmclog_process_map_in(po, (pid_t) -1, pkm->pm_address,
1432                     (char *) pkm->pm_file);
1433
1434         /*
1435          * TODO: Notify owners of (all) process-sampling PMCs too.
1436          */
1437
1438         return;
1439 }
1440
1441 static void
1442 pmc_process_kld_unload(struct pmckern_map_out *pkm)
1443 {
1444         struct pmc_owner *po;
1445
1446         sx_assert(&pmc_sx, SX_LOCKED);
1447
1448         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1449             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1450                 pmclog_process_map_out(po, (pid_t) -1,
1451                     pkm->pm_address, pkm->pm_address + pkm->pm_size);
1452
1453         /*
1454          * TODO: Notify owners of process-sampling PMCs.
1455          */
1456 }
1457
1458 /*
1459  * A mapping change for a process.
1460  */
1461
1462 static void
1463 pmc_process_mmap(struct thread *td, struct pmckern_map_in *pkm)
1464 {
1465         int ri;
1466         pid_t pid;
1467         char *fullpath, *freepath;
1468         const struct pmc *pm;
1469         struct pmc_owner *po;
1470         const struct pmc_process *pp;
1471
1472         freepath = fullpath = NULL;
1473         pmc_getfilename((struct vnode *) pkm->pm_file, &fullpath, &freepath);
1474
1475         pid = td->td_proc->p_pid;
1476
1477         /* Inform owners of all system-wide sampling PMCs. */
1478         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1479             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1480                 pmclog_process_map_in(po, pid, pkm->pm_address, fullpath);
1481
1482         if ((pp = pmc_find_process_descriptor(td->td_proc, 0)) == NULL)
1483                 goto done;
1484
1485         /*
1486          * Inform sampling PMC owners tracking this process.
1487          */
1488         for (ri = 0; ri < md->pmd_npmc; ri++)
1489                 if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL &&
1490                     PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
1491                         pmclog_process_map_in(pm->pm_owner,
1492                             pid, pkm->pm_address, fullpath);
1493
1494   done:
1495         if (freepath)
1496                 FREE(freepath, M_TEMP);
1497 }
1498
1499
1500 /*
1501  * Log an munmap request.
1502  */
1503
1504 static void
1505 pmc_process_munmap(struct thread *td, struct pmckern_map_out *pkm)
1506 {
1507         int ri;
1508         pid_t pid;
1509         struct pmc_owner *po;
1510         const struct pmc *pm;
1511         const struct pmc_process *pp;
1512
1513         pid = td->td_proc->p_pid;
1514
1515         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1516             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1517                 pmclog_process_map_out(po, pid, pkm->pm_address,
1518                     pkm->pm_address + pkm->pm_size);
1519
1520         if ((pp = pmc_find_process_descriptor(td->td_proc, 0)) == NULL)
1521                 return;
1522
1523         for (ri = 0; ri < md->pmd_npmc; ri++)
1524                 if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL &&
1525                     PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
1526                         pmclog_process_map_out(pm->pm_owner, pid,
1527                             pkm->pm_address, pkm->pm_address + pkm->pm_size);
1528 }
1529
1530 /*
1531  * The 'hook' invoked from the kernel proper
1532  */
1533
1534
1535 #ifdef  DEBUG
1536 const char *pmc_hooknames[] = {
1537         /* these strings correspond to PMC_FN_* in <sys/pmckern.h> */
1538         "",
1539         "EXEC",
1540         "CSW-IN",
1541         "CSW-OUT",
1542         "SAMPLE",
1543         "KLDLOAD",
1544         "KLDUNLOAD",
1545         "MMAP",
1546         "MUNMAP"
1547 };
1548 #endif
1549
1550 static int
1551 pmc_hook_handler(struct thread *td, int function, void *arg)
1552 {
1553
1554         PMCDBG(MOD,PMH,1, "hook td=%p func=%d \"%s\" arg=%p", td, function,
1555             pmc_hooknames[function], arg);
1556
1557         switch (function)
1558         {
1559
1560         /*
1561          * Process exec()
1562          */
1563
1564         case PMC_FN_PROCESS_EXEC:
1565         {
1566                 char *fullpath, *freepath;
1567                 unsigned int ri;
1568                 int is_using_hwpmcs;
1569                 struct pmc *pm;
1570                 struct proc *p;
1571                 struct pmc_owner *po;
1572                 struct pmc_process *pp;
1573                 struct pmckern_procexec *pk;
1574
1575                 sx_assert(&pmc_sx, SX_XLOCKED);
1576
1577                 p = td->td_proc;
1578                 pmc_getfilename(p->p_textvp, &fullpath, &freepath);
1579
1580                 pk = (struct pmckern_procexec *) arg;
1581
1582                 /* Inform owners of SS mode PMCs of the exec event. */
1583                 LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
1584                     if (po->po_flags & PMC_PO_OWNS_LOGFILE)
1585                             pmclog_process_procexec(po, PMC_ID_INVALID,
1586                                 p->p_pid, pk->pm_entryaddr, fullpath);
1587
1588                 PROC_LOCK(p);
1589                 is_using_hwpmcs = p->p_flag & P_HWPMC;
1590                 PROC_UNLOCK(p);
1591
1592                 if (!is_using_hwpmcs) {
1593                         if (freepath)
1594                                 FREE(freepath, M_TEMP);
1595                         break;
1596                 }
1597
1598                 /*
1599                  * PMCs are not inherited across an exec():  remove any
1600                  * PMCs that this process is the owner of.
1601                  */
1602
1603                 if ((po = pmc_find_owner_descriptor(p)) != NULL) {
1604                         pmc_remove_owner(po);
1605                         pmc_destroy_owner_descriptor(po);
1606                 }
1607
1608                 /*
1609                  * If the process being exec'ed is not the target of any
1610                  * PMC, we are done.
1611                  */
1612                 if ((pp = pmc_find_process_descriptor(p, 0)) == NULL) {
1613                         if (freepath)
1614                                 FREE(freepath, M_TEMP);
1615                         break;
1616                 }
1617
1618                 /*
1619                  * Log the exec event to all monitoring owners.  Skip
1620                  * owners who have already recieved the event because
1621                  * they had system sampling PMCs active.
1622                  */
1623                 for (ri = 0; ri < md->pmd_npmc; ri++)
1624                         if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL) {
1625                                 po = pm->pm_owner;
1626                                 if (po->po_sscount == 0 &&
1627                                     po->po_flags & PMC_PO_OWNS_LOGFILE)
1628                                         pmclog_process_procexec(po, pm->pm_id,
1629                                             p->p_pid, pk->pm_entryaddr,
1630                                             fullpath);
1631                         }
1632
1633                 if (freepath)
1634                         FREE(freepath, M_TEMP);
1635
1636
1637                 PMCDBG(PRC,EXC,1, "exec proc=%p (%d, %s) cred-changed=%d",
1638                     p, p->p_pid, p->p_comm, pk->pm_credentialschanged);
1639
1640                 if (pk->pm_credentialschanged == 0) /* no change */
1641                         break;
1642
1643                 /*
1644                  * If the newly exec()'ed process has a different credential
1645                  * than before, allow it to be the target of a PMC only if
1646                  * the PMC's owner has sufficient priviledge.
1647                  */
1648
1649                 for (ri = 0; ri < md->pmd_npmc; ri++)
1650                         if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL)
1651                                 if (pmc_can_attach(pm, td->td_proc) != 0)
1652                                         pmc_detach_one_process(td->td_proc,
1653                                             pm, PMC_FLAG_NONE);
1654
1655                 KASSERT(pp->pp_refcnt >= 0 && pp->pp_refcnt < (int) md->pmd_npmc,
1656                     ("[pmc,%d] Illegal ref count %d on pp %p", __LINE__,
1657                         pp->pp_refcnt, pp));
1658
1659                 /*
1660                  * If this process is no longer the target of any
1661                  * PMCs, we can remove the process entry and free
1662                  * up space.
1663                  */
1664
1665                 if (pp->pp_refcnt == 0) {
1666                         pmc_remove_process_descriptor(pp);
1667                         FREE(pp, M_PMC);
1668                         break;
1669                 }
1670
1671         }
1672         break;
1673
1674         case PMC_FN_CSW_IN:
1675                 pmc_process_csw_in(td);
1676                 break;
1677
1678         case PMC_FN_CSW_OUT:
1679                 pmc_process_csw_out(td);
1680                 break;
1681
1682         /*
1683          * Process accumulated PC samples.
1684          *
1685          * This function is expected to be called by hardclock() for
1686          * each CPU that has accumulated PC samples.
1687          *
1688          * This function is to be executed on the CPU whose samples
1689          * are being processed.
1690          */
1691         case PMC_FN_DO_SAMPLES:
1692
1693                 /*
1694                  * Clear the cpu specific bit in the CPU mask before
1695                  * do the rest of the processing.  If the NMI handler
1696                  * gets invoked after the "atomic_clear_int()" call
1697                  * below but before "pmc_process_samples()" gets
1698                  * around to processing the interrupt, then we will
1699                  * come back here at the next hardclock() tick (and
1700                  * may find nothing to do if "pmc_process_samples()"
1701                  * had already processed the interrupt).  We don't
1702                  * lose the interrupt sample.
1703                  */
1704                 atomic_clear_int(&pmc_cpumask, (1 << PCPU_GET(cpuid)));
1705                 pmc_process_samples(PCPU_GET(cpuid));
1706                 break;
1707
1708
1709         case PMC_FN_KLD_LOAD:
1710                 sx_assert(&pmc_sx, SX_LOCKED);
1711                 pmc_process_kld_load((struct pmckern_map_in *) arg);
1712                 break;
1713
1714         case PMC_FN_KLD_UNLOAD:
1715                 sx_assert(&pmc_sx, SX_LOCKED);
1716                 pmc_process_kld_unload((struct pmckern_map_out *) arg);
1717                 break;
1718
1719         case PMC_FN_MMAP:
1720                 sx_assert(&pmc_sx, SX_LOCKED);
1721                 pmc_process_mmap(td, (struct pmckern_map_in *) arg);
1722                 break;
1723
1724         case PMC_FN_MUNMAP:
1725                 sx_assert(&pmc_sx, SX_LOCKED);
1726                 pmc_process_munmap(td, (struct pmckern_map_out *) arg);
1727                 break;
1728
1729         default:
1730 #ifdef  DEBUG
1731                 KASSERT(0, ("[pmc,%d] unknown hook %d\n", __LINE__, function));
1732 #endif
1733                 break;
1734
1735         }
1736
1737         return 0;
1738 }
1739
1740 /*
1741  * allocate a 'struct pmc_owner' descriptor in the owner hash table.
1742  */
1743
1744 static struct pmc_owner *
1745 pmc_allocate_owner_descriptor(struct proc *p)
1746 {
1747         uint32_t hindex;
1748         struct pmc_owner *po;
1749         struct pmc_ownerhash *poh;
1750
1751         hindex = PMC_HASH_PTR(p, pmc_ownerhashmask);
1752         poh = &pmc_ownerhash[hindex];
1753
1754         /* allocate space for N pointers and one descriptor struct */
1755         MALLOC(po, struct pmc_owner *, sizeof(struct pmc_owner),
1756             M_PMC, M_ZERO|M_WAITOK);
1757
1758         po->po_sscount = po->po_error = po->po_flags = 0;
1759         po->po_file  = NULL;
1760         po->po_owner = p;
1761         po->po_kthread = NULL;
1762         LIST_INIT(&po->po_pmcs);
1763         LIST_INSERT_HEAD(poh, po, po_next); /* insert into hash table */
1764
1765         TAILQ_INIT(&po->po_logbuffers);
1766         mtx_init(&po->po_mtx, "pmc-owner-mtx", "pmc-per-proc", MTX_SPIN);
1767
1768         PMCDBG(OWN,ALL,1, "allocate-owner proc=%p (%d, %s) pmc-owner=%p",
1769             p, p->p_pid, p->p_comm, po);
1770
1771         return po;
1772 }
1773
1774 static void
1775 pmc_destroy_owner_descriptor(struct pmc_owner *po)
1776 {
1777
1778         PMCDBG(OWN,REL,1, "destroy-owner po=%p proc=%p (%d, %s)",
1779             po, po->po_owner, po->po_owner->p_pid, po->po_owner->p_comm);
1780
1781         mtx_destroy(&po->po_mtx);
1782         FREE(po, M_PMC);
1783 }
1784
1785 /*
1786  * find the descriptor corresponding to process 'p', adding or removing it
1787  * as specified by 'mode'.
1788  */
1789
1790 static struct pmc_process *
1791 pmc_find_process_descriptor(struct proc *p, uint32_t mode)
1792 {
1793         uint32_t hindex;
1794         struct pmc_process *pp, *ppnew;
1795         struct pmc_processhash *pph;
1796
1797         hindex = PMC_HASH_PTR(p, pmc_processhashmask);
1798         pph = &pmc_processhash[hindex];
1799
1800         ppnew = NULL;
1801
1802         /*
1803          * Pre-allocate memory in the FIND_ALLOCATE case since we
1804          * cannot call malloc(9) once we hold a spin lock.
1805          */
1806
1807         if (mode & PMC_FLAG_ALLOCATE) {
1808                 /* allocate additional space for 'n' pmc pointers */
1809                 MALLOC(ppnew, struct pmc_process *,
1810                     sizeof(struct pmc_process) + md->pmd_npmc *
1811                     sizeof(struct pmc_targetstate), M_PMC, M_ZERO|M_WAITOK);
1812         }
1813
1814         mtx_lock_spin(&pmc_processhash_mtx);
1815         LIST_FOREACH(pp, pph, pp_next)
1816             if (pp->pp_proc == p)
1817                     break;
1818
1819         if ((mode & PMC_FLAG_REMOVE) && pp != NULL)
1820                 LIST_REMOVE(pp, pp_next);
1821
1822         if ((mode & PMC_FLAG_ALLOCATE) && pp == NULL &&
1823             ppnew != NULL) {
1824                 ppnew->pp_proc = p;
1825                 LIST_INSERT_HEAD(pph, ppnew, pp_next);
1826                 pp = ppnew;
1827                 ppnew = NULL;
1828         }
1829         mtx_unlock_spin(&pmc_processhash_mtx);
1830
1831         if (pp != NULL && ppnew != NULL)
1832                 FREE(ppnew, M_PMC);
1833
1834         return pp;
1835 }
1836
1837 /*
1838  * remove a process descriptor from the process hash table.
1839  */
1840
1841 static void
1842 pmc_remove_process_descriptor(struct pmc_process *pp)
1843 {
1844         KASSERT(pp->pp_refcnt == 0,
1845             ("[pmc,%d] Removing process descriptor %p with count %d",
1846                 __LINE__, pp, pp->pp_refcnt));
1847
1848         mtx_lock_spin(&pmc_processhash_mtx);
1849         LIST_REMOVE(pp, pp_next);
1850         mtx_unlock_spin(&pmc_processhash_mtx);
1851 }
1852
1853
1854 /*
1855  * find an owner descriptor corresponding to proc 'p'
1856  */
1857
1858 static struct pmc_owner *
1859 pmc_find_owner_descriptor(struct proc *p)
1860 {
1861         uint32_t hindex;
1862         struct pmc_owner *po;
1863         struct pmc_ownerhash *poh;
1864
1865         hindex = PMC_HASH_PTR(p, pmc_ownerhashmask);
1866         poh = &pmc_ownerhash[hindex];
1867
1868         po = NULL;
1869         LIST_FOREACH(po, poh, po_next)
1870             if (po->po_owner == p)
1871                     break;
1872
1873         PMCDBG(OWN,FND,1, "find-owner proc=%p (%d, %s) hindex=0x%x -> "
1874             "pmc-owner=%p", p, p->p_pid, p->p_comm, hindex, po);
1875
1876         return po;
1877 }
1878
1879 /*
1880  * pmc_allocate_pmc_descriptor
1881  *
1882  * Allocate a pmc descriptor and initialize its
1883  * fields.
1884  */
1885
1886 static struct pmc *
1887 pmc_allocate_pmc_descriptor(void)
1888 {
1889         struct pmc *pmc;
1890
1891         MALLOC(pmc, struct pmc *, sizeof(struct pmc), M_PMC, M_ZERO|M_WAITOK);
1892
1893         if (pmc != NULL) {
1894                 pmc->pm_owner = NULL;
1895                 LIST_INIT(&pmc->pm_targets);
1896         }
1897
1898         PMCDBG(PMC,ALL,1, "allocate-pmc -> pmc=%p", pmc);
1899
1900         return pmc;
1901 }
1902
1903 /*
1904  * Destroy a pmc descriptor.
1905  */
1906
1907 static void
1908 pmc_destroy_pmc_descriptor(struct pmc *pm)
1909 {
1910         (void) pm;
1911
1912 #ifdef  DEBUG
1913         KASSERT(pm->pm_state == PMC_STATE_DELETED ||
1914             pm->pm_state == PMC_STATE_FREE,
1915             ("[pmc,%d] destroying non-deleted PMC", __LINE__));
1916         KASSERT(LIST_EMPTY(&pm->pm_targets),
1917             ("[pmc,%d] destroying pmc with targets", __LINE__));
1918         KASSERT(pm->pm_owner == NULL,
1919             ("[pmc,%d] destroying pmc attached to an owner", __LINE__));
1920         KASSERT(pm->pm_runcount == 0,
1921             ("[pmc,%d] pmc has non-zero run count %d", __LINE__,
1922                 pm->pm_runcount));
1923 #endif
1924 }
1925
1926 static void
1927 pmc_wait_for_pmc_idle(struct pmc *pm)
1928 {
1929 #ifdef  DEBUG
1930         volatile int maxloop;
1931
1932         maxloop = 100 * mp_ncpus;
1933 #endif
1934
1935         /*
1936          * Loop (with a forced context switch) till the PMC's runcount
1937          * comes down to zero.
1938          */
1939         while (atomic_load_acq_32(&pm->pm_runcount) > 0) {
1940 #ifdef  DEBUG
1941                 maxloop--;
1942                 KASSERT(maxloop > 0,
1943                     ("[pmc,%d] (ri%d, rc%d) waiting too long for "
1944                         "pmc to be free", __LINE__,
1945                         PMC_TO_ROWINDEX(pm), pm->pm_runcount));
1946 #endif
1947                 pmc_force_context_switch();
1948         }
1949 }
1950
1951 /*
1952  * This function does the following things:
1953  *
1954  *  - detaches the PMC from hardware
1955  *  - unlinks all target threads that were attached to it
1956  *  - removes the PMC from its owner's list
1957  *  - destroy's the PMC private mutex
1958  *
1959  * Once this function completes, the given pmc pointer can be safely
1960  * FREE'd by the caller.
1961  */
1962
1963 static void
1964 pmc_release_pmc_descriptor(struct pmc *pm)
1965 {
1966         u_int ri, cpu;
1967         enum pmc_mode mode;
1968         struct pmc_hw *phw;
1969         struct pmc_owner *po;
1970         struct pmc_process *pp;
1971         struct pmc_target *ptgt, *tmp;
1972         struct pmc_binding pb;
1973
1974         sx_assert(&pmc_sx, SX_XLOCKED);
1975
1976         KASSERT(pm, ("[pmc,%d] null pmc", __LINE__));
1977
1978         ri   = PMC_TO_ROWINDEX(pm);
1979         mode = PMC_TO_MODE(pm);
1980
1981         PMCDBG(PMC,REL,1, "release-pmc pmc=%p ri=%d mode=%d", pm, ri,
1982             mode);
1983
1984         /*
1985          * First, we take the PMC off hardware.
1986          */
1987         cpu = 0;
1988         if (PMC_IS_SYSTEM_MODE(mode)) {
1989
1990                 /*
1991                  * A system mode PMC runs on a specific CPU.  Switch
1992                  * to this CPU and turn hardware off.
1993                  */
1994                 pmc_save_cpu_binding(&pb);
1995
1996                 cpu = PMC_TO_CPU(pm);
1997
1998                 pmc_select_cpu(cpu);
1999
2000                 /* switch off non-stalled CPUs */
2001                 if (pm->pm_state == PMC_STATE_RUNNING &&
2002                     pm->pm_stalled == 0) {
2003
2004                         phw = pmc_pcpu[cpu]->pc_hwpmcs[ri];
2005
2006                         KASSERT(phw->phw_pmc == pm,
2007                             ("[pmc, %d] pmc ptr ri(%d) hw(%p) pm(%p)",
2008                                 __LINE__, ri, phw->phw_pmc, pm));
2009                         PMCDBG(PMC,REL,2, "stopping cpu=%d ri=%d", cpu, ri);
2010
2011                         critical_enter();
2012                         md->pmd_stop_pmc(cpu, ri);
2013                         critical_exit();
2014                 }
2015
2016                 PMCDBG(PMC,REL,2, "decfg cpu=%d ri=%d", cpu, ri);
2017
2018                 critical_enter();
2019                 md->pmd_config_pmc(cpu, ri, NULL);
2020                 critical_exit();
2021
2022                 /* adjust the global and process count of SS mode PMCs */
2023                 if (mode == PMC_MODE_SS && pm->pm_state == PMC_STATE_RUNNING) {
2024                         po = pm->pm_owner;
2025                         po->po_sscount--;
2026                         if (po->po_sscount == 0) {
2027                                 atomic_subtract_rel_int(&pmc_ss_count, 1);
2028                                 LIST_REMOVE(po, po_ssnext);
2029                         }
2030                 }
2031
2032                 pm->pm_state = PMC_STATE_DELETED;
2033
2034                 pmc_restore_cpu_binding(&pb);
2035
2036                 /*
2037                  * We could have references to this PMC structure in
2038                  * the per-cpu sample queues.  Wait for the queue to
2039                  * drain.
2040                  */
2041                 pmc_wait_for_pmc_idle(pm);
2042
2043         } else if (PMC_IS_VIRTUAL_MODE(mode)) {
2044
2045                 /*
2046                  * A virtual PMC could be running on multiple CPUs at
2047                  * a given instant.
2048                  *
2049                  * By marking its state as DELETED, we ensure that
2050                  * this PMC is never further scheduled on hardware.
2051                  *
2052                  * Then we wait till all CPUs are done with this PMC.
2053                  */
2054                 pm->pm_state = PMC_STATE_DELETED;
2055
2056
2057                 /* Wait for the PMCs runcount to come to zero. */
2058                 pmc_wait_for_pmc_idle(pm);
2059
2060                 /*
2061                  * At this point the PMC is off all CPUs and cannot be
2062                  * freshly scheduled onto a CPU.  It is now safe to
2063                  * unlink all targets from this PMC.  If a
2064                  * process-record's refcount falls to zero, we remove
2065                  * it from the hash table.  The module-wide SX lock
2066                  * protects us from races.
2067                  */
2068                 LIST_FOREACH_SAFE(ptgt, &pm->pm_targets, pt_next, tmp) {
2069                         pp = ptgt->pt_process;
2070                         pmc_unlink_target_process(pm, pp); /* frees 'ptgt' */
2071
2072                         PMCDBG(PMC,REL,3, "pp->refcnt=%d", pp->pp_refcnt);
2073
2074                         /*
2075                          * If the target process record shows that no
2076                          * PMCs are attached to it, reclaim its space.
2077                          */
2078
2079                         if (pp->pp_refcnt == 0) {
2080                                 pmc_remove_process_descriptor(pp);
2081                                 FREE(pp, M_PMC);
2082                         }
2083                 }
2084
2085                 cpu = curthread->td_oncpu; /* setup cpu for pmd_release() */
2086
2087         }
2088
2089         /*
2090          * Release any MD resources
2091          */
2092
2093         (void) md->pmd_release_pmc(cpu, ri, pm);
2094
2095         /*
2096          * Update row disposition
2097          */
2098
2099         if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm)))
2100                 PMC_UNMARK_ROW_STANDALONE(ri);
2101         else
2102                 PMC_UNMARK_ROW_THREAD(ri);
2103
2104         /* unlink from the owner's list */
2105         if (pm->pm_owner) {
2106                 LIST_REMOVE(pm, pm_next);
2107                 pm->pm_owner = NULL;
2108         }
2109
2110         pmc_destroy_pmc_descriptor(pm);
2111 }
2112
2113 /*
2114  * Register an owner and a pmc.
2115  */
2116
2117 static int
2118 pmc_register_owner(struct proc *p, struct pmc *pmc)
2119 {
2120         struct pmc_owner *po;
2121
2122         sx_assert(&pmc_sx, SX_XLOCKED);
2123
2124         if ((po = pmc_find_owner_descriptor(p)) == NULL)
2125                 if ((po = pmc_allocate_owner_descriptor(p)) == NULL)
2126                         return ENOMEM;
2127
2128         KASSERT(pmc->pm_owner == NULL,
2129             ("[pmc,%d] attempting to own an initialized PMC", __LINE__));
2130         pmc->pm_owner  = po;
2131
2132         LIST_INSERT_HEAD(&po->po_pmcs, pmc, pm_next);
2133
2134         PROC_LOCK(p);
2135         p->p_flag |= P_HWPMC;
2136         PROC_UNLOCK(p);
2137
2138         if (po->po_flags & PMC_PO_OWNS_LOGFILE)
2139                 pmclog_process_pmcallocate(pmc);
2140
2141         PMCDBG(PMC,REG,1, "register-owner pmc-owner=%p pmc=%p",
2142             po, pmc);
2143
2144         return 0;
2145 }
2146
2147 /*
2148  * Return the current row disposition:
2149  * == 0 => FREE
2150  *  > 0 => PROCESS MODE
2151  *  < 0 => SYSTEM MODE
2152  */
2153
2154 int
2155 pmc_getrowdisp(int ri)
2156 {
2157         return pmc_pmcdisp[ri];
2158 }
2159
2160 /*
2161  * Check if a PMC at row index 'ri' can be allocated to the current
2162  * process.
2163  *
2164  * Allocation can fail if:
2165  *   - the current process is already being profiled by a PMC at index 'ri',
2166  *     attached to it via OP_PMCATTACH.
2167  *   - the current process has already allocated a PMC at index 'ri'
2168  *     via OP_ALLOCATE.
2169  */
2170
2171 static int
2172 pmc_can_allocate_rowindex(struct proc *p, unsigned int ri, int cpu)
2173 {
2174         enum pmc_mode mode;
2175         struct pmc *pm;
2176         struct pmc_owner *po;
2177         struct pmc_process *pp;
2178
2179         PMCDBG(PMC,ALR,1, "can-allocate-rowindex proc=%p (%d, %s) ri=%d "
2180             "cpu=%d", p, p->p_pid, p->p_comm, ri, cpu);
2181
2182         /*
2183          * We shouldn't have already allocated a process-mode PMC at
2184          * row index 'ri'.
2185          *
2186          * We shouldn't have allocated a system-wide PMC on the same
2187          * CPU and same RI.
2188          */
2189         if ((po = pmc_find_owner_descriptor(p)) != NULL)
2190                 LIST_FOREACH(pm, &po->po_pmcs, pm_next) {
2191                     if (PMC_TO_ROWINDEX(pm) == ri) {
2192                             mode = PMC_TO_MODE(pm);
2193                             if (PMC_IS_VIRTUAL_MODE(mode))
2194                                     return EEXIST;
2195                             if (PMC_IS_SYSTEM_MODE(mode) &&
2196                                 (int) PMC_TO_CPU(pm) == cpu)
2197                                     return EEXIST;
2198                     }
2199                 }
2200
2201         /*
2202          * We also shouldn't be the target of any PMC at this index
2203          * since otherwise a PMC_ATTACH to ourselves will fail.
2204          */
2205         if ((pp = pmc_find_process_descriptor(p, 0)) != NULL)
2206                 if (pp->pp_pmcs[ri].pp_pmc)
2207                         return EEXIST;
2208
2209         PMCDBG(PMC,ALR,2, "can-allocate-rowindex proc=%p (%d, %s) ri=%d ok",
2210             p, p->p_pid, p->p_comm, ri);
2211
2212         return 0;
2213 }
2214
2215 /*
2216  * Check if a given PMC at row index 'ri' can be currently used in
2217  * mode 'mode'.
2218  */
2219
2220 static int
2221 pmc_can_allocate_row(int ri, enum pmc_mode mode)
2222 {
2223         enum pmc_disp   disp;
2224
2225         sx_assert(&pmc_sx, SX_XLOCKED);
2226
2227         PMCDBG(PMC,ALR,1, "can-allocate-row ri=%d mode=%d", ri, mode);
2228
2229         if (PMC_IS_SYSTEM_MODE(mode))
2230                 disp = PMC_DISP_STANDALONE;
2231         else
2232                 disp = PMC_DISP_THREAD;
2233
2234         /*
2235          * check disposition for PMC row 'ri':
2236          *
2237          * Expected disposition         Row-disposition         Result
2238          *
2239          * STANDALONE                   STANDALONE or FREE      proceed
2240          * STANDALONE                   THREAD                  fail
2241          * THREAD                       THREAD or FREE          proceed
2242          * THREAD                       STANDALONE              fail
2243          */
2244
2245         if (!PMC_ROW_DISP_IS_FREE(ri) &&
2246             !(disp == PMC_DISP_THREAD && PMC_ROW_DISP_IS_THREAD(ri)) &&
2247             !(disp == PMC_DISP_STANDALONE && PMC_ROW_DISP_IS_STANDALONE(ri)))
2248                 return EBUSY;
2249
2250         /*
2251          * All OK
2252          */
2253
2254         PMCDBG(PMC,ALR,2, "can-allocate-row ri=%d mode=%d ok", ri, mode);
2255
2256         return 0;
2257
2258 }
2259
2260 /*
2261  * Find a PMC descriptor with user handle 'pmcid' for thread 'td'.
2262  */
2263
2264 static struct pmc *
2265 pmc_find_pmc_descriptor_in_process(struct pmc_owner *po, pmc_id_t pmcid)
2266 {
2267         struct pmc *pm;
2268
2269         KASSERT(PMC_ID_TO_ROWINDEX(pmcid) < md->pmd_npmc,
2270             ("[pmc,%d] Illegal pmc index %d (max %d)", __LINE__,
2271                 PMC_ID_TO_ROWINDEX(pmcid), md->pmd_npmc));
2272
2273         LIST_FOREACH(pm, &po->po_pmcs, pm_next)
2274             if (pm->pm_id == pmcid)
2275                     return pm;
2276
2277         return NULL;
2278 }
2279
2280 static int
2281 pmc_find_pmc(pmc_id_t pmcid, struct pmc **pmc)
2282 {
2283
2284         struct pmc *pm;
2285         struct pmc_owner *po;
2286
2287         PMCDBG(PMC,FND,1, "find-pmc id=%d", pmcid);
2288
2289         if ((po = pmc_find_owner_descriptor(curthread->td_proc)) == NULL)
2290                 return ESRCH;
2291
2292         if ((pm = pmc_find_pmc_descriptor_in_process(po, pmcid)) == NULL)
2293                 return EINVAL;
2294
2295         PMCDBG(PMC,FND,2, "find-pmc id=%d -> pmc=%p", pmcid, pm);
2296
2297         *pmc = pm;
2298         return 0;
2299 }
2300
2301 /*
2302  * Start a PMC.
2303  */
2304
2305 static int
2306 pmc_start(struct pmc *pm)
2307 {
2308         int error, cpu, ri;
2309         enum pmc_mode mode;
2310         struct pmc_owner *po;
2311         struct pmc_binding pb;
2312
2313         KASSERT(pm != NULL,
2314             ("[pmc,%d] null pm", __LINE__));
2315
2316         mode = PMC_TO_MODE(pm);
2317         ri   = PMC_TO_ROWINDEX(pm);
2318         error = 0;
2319
2320         PMCDBG(PMC,OPS,1, "start pmc=%p mode=%d ri=%d", pm, mode, ri);
2321
2322         po = pm->pm_owner;
2323
2324         if (PMC_IS_VIRTUAL_MODE(mode)) {
2325
2326                 /*
2327                  * If a PMCATTACH has never been done on this PMC,
2328                  * attach it to its owner process.
2329                  */
2330
2331                 if (LIST_EMPTY(&pm->pm_targets))
2332                         error = (pm->pm_flags & PMC_F_ATTACH_DONE) ? ESRCH :
2333                             pmc_attach_process(po->po_owner, pm);
2334
2335                 /*
2336                  * Disallow PMCSTART if a logfile is required but has not
2337                  * been configured yet.
2338                  */
2339
2340                 if (error == 0 && (pm->pm_flags & PMC_F_NEEDS_LOGFILE) &&
2341                     (po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)
2342                         error = EDOOFUS;
2343
2344                 /*
2345                  * If the PMC is attached to its owner, then force a context
2346                  * switch to ensure that the MD state gets set correctly.
2347                  */
2348
2349                 if (error == 0) {
2350                         pm->pm_state = PMC_STATE_RUNNING;
2351                         if (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER)
2352                                 pmc_force_context_switch();
2353                 }
2354
2355                 return error;
2356         }
2357
2358
2359         /*
2360          * A system-wide PMC.
2361          */
2362
2363         if ((pm->pm_flags & PMC_F_NEEDS_LOGFILE) &&
2364             (po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)
2365                 return EDOOFUS; /* programming error */
2366
2367         /*
2368          * Add the owner to the global list if this is a system-wide
2369          * sampling PMC.
2370          */
2371
2372         if (mode == PMC_MODE_SS) {
2373                 if (po->po_sscount == 0) {
2374                         LIST_INSERT_HEAD(&pmc_ss_owners, po, po_ssnext);
2375                         atomic_add_rel_int(&pmc_ss_count, 1);
2376                         PMCDBG(PMC,OPS,1, "po=%p in global list", po);
2377                 }
2378                 po->po_sscount++;
2379         }
2380
2381         /* TODO: dump system wide process mappings to the log? */
2382
2383         /*
2384          * Move to the CPU associated with this
2385          * PMC, and start the hardware.
2386          */
2387
2388         pmc_save_cpu_binding(&pb);
2389
2390         cpu = PMC_TO_CPU(pm);
2391
2392         if (pmc_cpu_is_disabled(cpu))
2393                 return ENXIO;
2394
2395         pmc_select_cpu(cpu);
2396
2397         /*
2398          * global PMCs are configured at allocation time
2399          * so write out the initial value and start the PMC.
2400          */
2401
2402         pm->pm_state = PMC_STATE_RUNNING;
2403
2404         critical_enter();
2405         if ((error = md->pmd_write_pmc(cpu, ri,
2406                  PMC_IS_SAMPLING_MODE(mode) ?
2407                  pm->pm_sc.pm_reloadcount :
2408                  pm->pm_sc.pm_initial)) == 0)
2409                 error = md->pmd_start_pmc(cpu, ri);
2410         critical_exit();
2411
2412         pmc_restore_cpu_binding(&pb);
2413
2414         return error;
2415 }
2416
2417 /*
2418  * Stop a PMC.
2419  */
2420
2421 static int
2422 pmc_stop(struct pmc *pm)
2423 {
2424         int cpu, error, ri;
2425         struct pmc_owner *po;
2426         struct pmc_binding pb;
2427
2428         KASSERT(pm != NULL, ("[pmc,%d] null pmc", __LINE__));
2429
2430         PMCDBG(PMC,OPS,1, "stop pmc=%p mode=%d ri=%d", pm,
2431             PMC_TO_MODE(pm), PMC_TO_ROWINDEX(pm));
2432
2433         pm->pm_state = PMC_STATE_STOPPED;
2434
2435         /*
2436          * If the PMC is a virtual mode one, changing the state to
2437          * non-RUNNING is enough to ensure that the PMC never gets
2438          * scheduled.
2439          *
2440          * If this PMC is current running on a CPU, then it will
2441          * handled correctly at the time its target process is context
2442          * switched out.
2443          */
2444
2445         if (PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)))
2446                 return 0;
2447
2448         /*
2449          * A system-mode PMC.  Move to the CPU associated with
2450          * this PMC, and stop the hardware.  We update the
2451          * 'initial count' so that a subsequent PMCSTART will
2452          * resume counting from the current hardware count.
2453          */
2454
2455         pmc_save_cpu_binding(&pb);
2456
2457         cpu = PMC_TO_CPU(pm);
2458
2459         KASSERT(cpu >= 0 && cpu < mp_ncpus,
2460             ("[pmc,%d] illegal cpu=%d", __LINE__, cpu));
2461
2462         if (pmc_cpu_is_disabled(cpu))
2463                 return ENXIO;
2464
2465         pmc_select_cpu(cpu);
2466
2467         ri = PMC_TO_ROWINDEX(pm);
2468
2469         critical_enter();
2470         if ((error = md->pmd_stop_pmc(cpu, ri)) == 0)
2471                 error = md->pmd_read_pmc(cpu, ri, &pm->pm_sc.pm_initial);
2472         critical_exit();
2473
2474         pmc_restore_cpu_binding(&pb);
2475
2476         po = pm->pm_owner;
2477
2478         /* remove this owner from the global list of SS PMC owners */
2479         if (PMC_TO_MODE(pm) == PMC_MODE_SS) {
2480                 po->po_sscount--;
2481                 if (po->po_sscount == 0) {
2482                         atomic_subtract_rel_int(&pmc_ss_count, 1);
2483                         LIST_REMOVE(po, po_ssnext);
2484                         PMCDBG(PMC,OPS,2,"po=%p removed from global list", po);
2485                 }
2486         }
2487
2488         return error;
2489 }
2490
2491
2492 #ifdef  DEBUG
2493 static const char *pmc_op_to_name[] = {
2494 #undef  __PMC_OP
2495 #define __PMC_OP(N, D)  #N ,
2496         __PMC_OPS()
2497         NULL
2498 };
2499 #endif
2500
2501 /*
2502  * The syscall interface
2503  */
2504
2505 #define PMC_GET_SX_XLOCK(...) do {              \
2506         sx_xlock(&pmc_sx);                      \
2507         if (pmc_hook == NULL) {                 \
2508                 sx_xunlock(&pmc_sx);            \
2509                 return __VA_ARGS__;             \
2510         }                                       \
2511 } while (0)
2512
2513 #define PMC_DOWNGRADE_SX() do {                 \
2514         sx_downgrade(&pmc_sx);                  \
2515         is_sx_downgraded = 1;                   \
2516 } while (0)
2517
2518 static int
2519 pmc_syscall_handler(struct thread *td, void *syscall_args)
2520 {
2521         int error, is_sx_downgraded, op;
2522         struct pmc_syscall_args *c;
2523         void *arg;
2524
2525         PMC_GET_SX_XLOCK(ENOSYS);
2526
2527         DROP_GIANT();
2528
2529         is_sx_downgraded = 0;
2530
2531         c = (struct pmc_syscall_args *) syscall_args;
2532
2533         op = c->pmop_code;
2534         arg = c->pmop_data;
2535
2536         PMCDBG(MOD,PMS,1, "syscall op=%d \"%s\" arg=%p", op,
2537             pmc_op_to_name[op], arg);
2538
2539         error = 0;
2540         atomic_add_int(&pmc_stats.pm_syscalls, 1);
2541
2542         switch(op)
2543         {
2544
2545
2546         /*
2547          * Configure a log file.
2548          *
2549          * XXX This OP will be reworked.
2550          */
2551
2552         case PMC_OP_CONFIGURELOG:
2553         {
2554                 struct proc *p;
2555                 struct pmc *pm;
2556                 struct pmc_owner *po;
2557                 struct pmckern_map_in *km, *kmbase;
2558                 struct pmc_op_configurelog cl;
2559
2560                 sx_assert(&pmc_sx, SX_XLOCKED);
2561
2562                 if ((error = copyin(arg, &cl, sizeof(cl))) != 0)
2563                         break;
2564
2565                 /* mark this process as owning a log file */
2566                 p = td->td_proc;
2567                 if ((po = pmc_find_owner_descriptor(p)) == NULL)
2568                         if ((po = pmc_allocate_owner_descriptor(p)) == NULL) {
2569                                 error = ENOMEM;
2570                                 break;
2571                         }
2572
2573                 /*
2574                  * If a valid fd was passed in, try to configure that,
2575                  * otherwise if 'fd' was less than zero and there was
2576                  * a log file configured, flush its buffers and
2577                  * de-configure it.
2578                  */
2579                 if (cl.pm_logfd >= 0)
2580                         error = pmclog_configure_log(po, cl.pm_logfd);
2581                 else if (po->po_flags & PMC_PO_OWNS_LOGFILE) {
2582                         pmclog_process_closelog(po);
2583                         error = pmclog_flush(po);
2584                         if (error == 0) {
2585                                 LIST_FOREACH(pm, &po->po_pmcs, pm_next)
2586                                     if (pm->pm_flags & PMC_F_NEEDS_LOGFILE &&
2587                                         pm->pm_state == PMC_STATE_RUNNING)
2588                                             pmc_stop(pm);
2589                                 error = pmclog_deconfigure_log(po);
2590                         }
2591                 } else
2592                         error = EINVAL;
2593
2594                 if (error)
2595                         break;
2596
2597                 /*
2598                  * Log the current set of kernel modules.
2599                  */
2600                 kmbase = linker_hwpmc_list_objects();
2601                 for (km = kmbase; km->pm_file != NULL; km++) {
2602                         PMCDBG(LOG,REG,1,"%s %p", (char *) km->pm_file,
2603                             (void *) km->pm_address);
2604                         pmclog_process_map_in(po, (pid_t) -1, km->pm_address,
2605                             km->pm_file);
2606                 }
2607                 FREE(kmbase, M_LINKER);
2608         }
2609         break;
2610
2611
2612         /*
2613          * Flush a log file.
2614          */
2615
2616         case PMC_OP_FLUSHLOG:
2617         {
2618                 struct pmc_owner *po;
2619
2620                 sx_assert(&pmc_sx, SX_XLOCKED);
2621
2622                 if ((po = pmc_find_owner_descriptor(td->td_proc)) == NULL) {
2623                         error = EINVAL;
2624                         break;
2625                 }
2626
2627                 error = pmclog_flush(po);
2628         }
2629         break;
2630
2631         /*
2632          * Retrieve hardware configuration.
2633          */
2634
2635         case PMC_OP_GETCPUINFO: /* CPU information */
2636         {
2637                 struct pmc_op_getcpuinfo gci;
2638
2639                 gci.pm_cputype = md->pmd_cputype;
2640                 gci.pm_ncpu    = mp_ncpus;
2641                 gci.pm_npmc    = md->pmd_npmc;
2642                 gci.pm_nclass  = md->pmd_nclass;
2643                 bcopy(md->pmd_classes, &gci.pm_classes,
2644                     sizeof(gci.pm_classes));
2645                 error = copyout(&gci, arg, sizeof(gci));
2646         }
2647         break;
2648
2649
2650         /*
2651          * Get module statistics
2652          */
2653
2654         case PMC_OP_GETDRIVERSTATS:
2655         {
2656                 struct pmc_op_getdriverstats gms;
2657
2658                 bcopy(&pmc_stats, &gms, sizeof(gms));
2659                 error = copyout(&gms, arg, sizeof(gms));
2660         }
2661         break;
2662
2663
2664         /*
2665          * Retrieve module version number
2666          */
2667
2668         case PMC_OP_GETMODULEVERSION:
2669         {
2670                 uint32_t cv, modv;
2671
2672                 /* retrieve the client's idea of the ABI version */
2673                 if ((error = copyin(arg, &cv, sizeof(uint32_t))) != 0)
2674                         break;
2675                 /* don't service clients newer than our driver */
2676                 modv = PMC_VERSION;
2677                 if ((cv & 0xFFFF0000) > (modv & 0xFFFF0000)) {
2678                         error = EPROGMISMATCH;
2679                         break;
2680                 }
2681                 error = copyout(&modv, arg, sizeof(int));
2682         }
2683         break;
2684
2685
2686         /*
2687          * Retrieve the state of all the PMCs on a given
2688          * CPU.
2689          */
2690
2691         case PMC_OP_GETPMCINFO:
2692         {
2693                 uint32_t cpu, n, npmc;
2694                 size_t pmcinfo_size;
2695                 struct pmc *pm;
2696                 struct pmc_info *p, *pmcinfo;
2697                 struct pmc_op_getpmcinfo *gpi;
2698                 struct pmc_owner *po;
2699                 struct pmc_binding pb;
2700
2701                 PMC_DOWNGRADE_SX();
2702
2703                 gpi = (struct pmc_op_getpmcinfo *) arg;
2704
2705                 if ((error = copyin(&gpi->pm_cpu, &cpu, sizeof(cpu))) != 0)
2706                         break;
2707
2708                 if (cpu >= (unsigned int) mp_ncpus) {
2709                         error = EINVAL;
2710                         break;
2711                 }
2712
2713                 if (pmc_cpu_is_disabled(cpu)) {
2714                         error = ENXIO;
2715                         break;
2716                 }
2717
2718                 /* switch to CPU 'cpu' */
2719                 pmc_save_cpu_binding(&pb);
2720                 pmc_select_cpu(cpu);
2721
2722                 npmc = md->pmd_npmc;
2723
2724                 pmcinfo_size = npmc * sizeof(struct pmc_info);
2725                 MALLOC(pmcinfo, struct pmc_info *, pmcinfo_size, M_PMC,
2726                     M_WAITOK);
2727
2728                 p = pmcinfo;
2729
2730                 for (n = 0; n < md->pmd_npmc; n++, p++) {
2731
2732                         if ((error = md->pmd_describe(cpu, n, p, &pm)) != 0)
2733                                 break;
2734
2735                         if (PMC_ROW_DISP_IS_STANDALONE(n))
2736                                 p->pm_rowdisp = PMC_DISP_STANDALONE;
2737                         else if (PMC_ROW_DISP_IS_THREAD(n))
2738                                 p->pm_rowdisp = PMC_DISP_THREAD;
2739                         else
2740                                 p->pm_rowdisp = PMC_DISP_FREE;
2741
2742                         p->pm_ownerpid = -1;
2743
2744                         if (pm == NULL) /* no PMC associated */
2745                                 continue;
2746
2747                         po = pm->pm_owner;
2748
2749                         KASSERT(po->po_owner != NULL,
2750                             ("[pmc,%d] pmc_owner had a null proc pointer",
2751                                 __LINE__));
2752
2753                         p->pm_ownerpid = po->po_owner->p_pid;
2754                         p->pm_mode     = PMC_TO_MODE(pm);
2755                         p->pm_event    = pm->pm_event;
2756                         p->pm_flags    = pm->pm_flags;
2757
2758                         if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
2759                                 p->pm_reloadcount =
2760                                     pm->pm_sc.pm_reloadcount;
2761                 }
2762
2763                 pmc_restore_cpu_binding(&pb);
2764
2765                 /* now copy out the PMC info collected */
2766                 if (error == 0)
2767                         error = copyout(pmcinfo, &gpi->pm_pmcs, pmcinfo_size);
2768
2769                 FREE(pmcinfo, M_PMC);
2770         }
2771         break;
2772
2773
2774         /*
2775          * Set the administrative state of a PMC.  I.e. whether
2776          * the PMC is to be used or not.
2777          */
2778
2779         case PMC_OP_PMCADMIN:
2780         {
2781                 int cpu, ri;
2782                 enum pmc_state request;
2783                 struct pmc_cpu *pc;
2784                 struct pmc_hw *phw;
2785                 struct pmc_op_pmcadmin pma;
2786                 struct pmc_binding pb;
2787
2788                 sx_assert(&pmc_sx, SX_XLOCKED);
2789
2790                 KASSERT(td == curthread,
2791                     ("[pmc,%d] td != curthread", __LINE__));
2792
2793                 error = priv_check(td, PRIV_PMC_MANAGE);
2794                 if (error)
2795                         break;
2796
2797                 if ((error = copyin(arg, &pma, sizeof(pma))) != 0)
2798                         break;
2799
2800                 cpu = pma.pm_cpu;
2801
2802                 if (cpu < 0 || cpu >= mp_ncpus) {
2803                         error = EINVAL;
2804                         break;
2805                 }
2806
2807                 if (pmc_cpu_is_disabled(cpu)) {
2808                         error = ENXIO;
2809                         break;
2810                 }
2811
2812                 request = pma.pm_state;
2813
2814                 if (request != PMC_STATE_DISABLED &&
2815                     request != PMC_STATE_FREE) {
2816                         error = EINVAL;
2817                         break;
2818                 }
2819
2820                 ri = pma.pm_pmc; /* pmc id == row index */
2821                 if (ri < 0 || ri >= (int) md->pmd_npmc) {
2822                         error = EINVAL;
2823                         break;
2824                 }
2825
2826                 /*
2827                  * We can't disable a PMC with a row-index allocated
2828                  * for process virtual PMCs.
2829                  */
2830
2831                 if (PMC_ROW_DISP_IS_THREAD(ri) &&
2832                     request == PMC_STATE_DISABLED) {
2833                         error = EBUSY;
2834                         break;
2835                 }
2836
2837                 /*
2838                  * otherwise, this PMC on this CPU is either free or
2839                  * in system-wide mode.
2840                  */
2841
2842                 pmc_save_cpu_binding(&pb);
2843                 pmc_select_cpu(cpu);
2844
2845                 pc  = pmc_pcpu[cpu];
2846                 phw = pc->pc_hwpmcs[ri];
2847
2848                 /*
2849                  * XXX do we need some kind of 'forced' disable?
2850                  */
2851
2852                 if (phw->phw_pmc == NULL) {
2853                         if (request == PMC_STATE_DISABLED &&
2854                             (phw->phw_state & PMC_PHW_FLAG_IS_ENABLED)) {
2855                                 phw->phw_state &= ~PMC_PHW_FLAG_IS_ENABLED;
2856                                 PMC_MARK_ROW_STANDALONE(ri);
2857                         } else if (request == PMC_STATE_FREE &&
2858                             (phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) == 0) {
2859                                 phw->phw_state |=  PMC_PHW_FLAG_IS_ENABLED;
2860                                 PMC_UNMARK_ROW_STANDALONE(ri);
2861                         }
2862                         /* other cases are a no-op */
2863                 } else
2864                         error = EBUSY;
2865
2866                 pmc_restore_cpu_binding(&pb);
2867         }
2868         break;
2869
2870
2871         /*
2872          * Allocate a PMC.
2873          */
2874
2875         case PMC_OP_PMCALLOCATE:
2876         {
2877                 uint32_t caps;
2878                 u_int cpu;
2879                 int n;
2880                 enum pmc_mode mode;
2881                 struct pmc *pmc;
2882                 struct pmc_hw *phw;
2883                 struct pmc_op_pmcallocate pa;
2884                 struct pmc_binding pb;
2885
2886                 if ((error = copyin(arg, &pa, sizeof(pa))) != 0)
2887                         break;
2888
2889                 caps = pa.pm_caps;
2890                 mode = pa.pm_mode;
2891                 cpu  = pa.pm_cpu;
2892
2893                 if ((mode != PMC_MODE_SS  &&  mode != PMC_MODE_SC  &&
2894                      mode != PMC_MODE_TS  &&  mode != PMC_MODE_TC) ||
2895                     (cpu != (u_int) PMC_CPU_ANY && cpu >= (u_int) mp_ncpus)) {
2896                         error = EINVAL;
2897                         break;
2898                 }
2899
2900                 /*
2901                  * Virtual PMCs should only ask for a default CPU.
2902                  * System mode PMCs need to specify a non-default CPU.
2903                  */
2904
2905                 if ((PMC_IS_VIRTUAL_MODE(mode) && cpu != (u_int) PMC_CPU_ANY) ||
2906                     (PMC_IS_SYSTEM_MODE(mode) && cpu == (u_int) PMC_CPU_ANY)) {
2907                         error = EINVAL;
2908                         break;
2909                 }
2910
2911                 /*
2912                  * Check that a disabled CPU is not being asked for.
2913                  */
2914
2915                 if (PMC_IS_SYSTEM_MODE(mode) && pmc_cpu_is_disabled(cpu)) {
2916                         error = ENXIO;
2917                         break;
2918                 }
2919
2920                 /*
2921                  * Refuse an allocation for a system-wide PMC if this
2922                  * process has been jailed, or if this process lacks
2923                  * super-user credentials and the sysctl tunable
2924                  * 'security.bsd.unprivileged_syspmcs' is zero.
2925                  */
2926
2927                 if (PMC_IS_SYSTEM_MODE(mode)) {
2928                         if (jailed(curthread->td_ucred)) {
2929                                 error = EPERM;
2930                                 break;
2931                         }
2932                         if (!pmc_unprivileged_syspmcs) {
2933                                 error = priv_check(curthread,
2934                                     PRIV_PMC_SYSTEM);
2935                                 if (error)
2936                                         break;
2937                         }
2938                 }
2939
2940                 if (error)
2941                         break;
2942
2943                 /*
2944                  * Look for valid values for 'pm_flags'
2945                  */
2946
2947                 if ((pa.pm_flags & ~(PMC_F_DESCENDANTS | PMC_F_LOG_PROCCSW |
2948                     PMC_F_LOG_PROCEXIT)) != 0) {
2949                         error = EINVAL;
2950                         break;
2951                 }
2952
2953                 /* process logging options are not allowed for system PMCs */
2954                 if (PMC_IS_SYSTEM_MODE(mode) && (pa.pm_flags &
2955                     (PMC_F_LOG_PROCCSW | PMC_F_LOG_PROCEXIT))) {
2956                         error = EINVAL;
2957                         break;
2958                 }
2959
2960                 /*
2961                  * All sampling mode PMCs need to be able to interrupt the
2962                  * CPU.
2963                  */
2964                 if (PMC_IS_SAMPLING_MODE(mode))
2965                         caps |= PMC_CAP_INTERRUPT;
2966
2967                 /* A valid class specifier should have been passed in. */
2968                 for (n = 0; n < md->pmd_nclass; n++)
2969                         if (md->pmd_classes[n].pm_class == pa.pm_class)
2970                                 break;
2971                 if (n == md->pmd_nclass) {
2972                         error = EINVAL;
2973                         break;
2974                 }
2975
2976                 /* The requested PMC capabilities should be feasible. */
2977                 if ((md->pmd_classes[n].pm_caps & caps) != caps) {
2978                         error = EOPNOTSUPP;
2979                         break;
2980                 }
2981
2982                 PMCDBG(PMC,ALL,2, "event=%d caps=0x%x mode=%d cpu=%d",
2983                     pa.pm_ev, caps, mode, cpu);
2984
2985                 pmc = pmc_allocate_pmc_descriptor();
2986                 pmc->pm_id    = PMC_ID_MAKE_ID(cpu,pa.pm_mode,pa.pm_class,
2987                     PMC_ID_INVALID);
2988                 pmc->pm_event = pa.pm_ev;
2989                 pmc->pm_state = PMC_STATE_FREE;
2990                 pmc->pm_caps  = caps;
2991                 pmc->pm_flags = pa.pm_flags;
2992
2993                 /* switch thread to CPU 'cpu' */
2994                 pmc_save_cpu_binding(&pb);
2995
2996 #define PMC_IS_SHAREABLE_PMC(cpu, n)                            \
2997         (pmc_pcpu[(cpu)]->pc_hwpmcs[(n)]->phw_state &           \
2998          PMC_PHW_FLAG_IS_SHAREABLE)
2999 #define PMC_IS_UNALLOCATED(cpu, n)                              \
3000         (pmc_pcpu[(cpu)]->pc_hwpmcs[(n)]->phw_pmc == NULL)
3001
3002                 if (PMC_IS_SYSTEM_MODE(mode)) {
3003                         pmc_select_cpu(cpu);
3004                         for (n = 0; n < (int) md->pmd_npmc; n++)
3005                                 if (pmc_can_allocate_row(n, mode) == 0 &&
3006                                     pmc_can_allocate_rowindex(
3007                                             curthread->td_proc, n, cpu) == 0 &&
3008                                     (PMC_IS_UNALLOCATED(cpu, n) ||
3009                                      PMC_IS_SHAREABLE_PMC(cpu, n)) &&
3010                                     md->pmd_allocate_pmc(cpu, n, pmc,
3011                                         &pa) == 0)
3012                                         break;
3013                 } else {
3014                         /* Process virtual mode */
3015                         for (n = 0; n < (int) md->pmd_npmc; n++) {
3016                                 if (pmc_can_allocate_row(n, mode) == 0 &&
3017                                     pmc_can_allocate_rowindex(
3018                                             curthread->td_proc, n,
3019                                             PMC_CPU_ANY) == 0 &&
3020                                     md->pmd_allocate_pmc(curthread->td_oncpu,
3021                                         n, pmc, &pa) == 0)
3022                                         break;
3023                         }
3024                 }
3025
3026 #undef  PMC_IS_UNALLOCATED
3027 #undef  PMC_IS_SHAREABLE_PMC
3028
3029                 pmc_restore_cpu_binding(&pb);
3030
3031                 if (n == (int) md->pmd_npmc) {
3032                         pmc_destroy_pmc_descriptor(pmc);
3033                         FREE(pmc, M_PMC);
3034                         pmc = NULL;
3035                         error = EINVAL;
3036                         break;
3037                 }
3038
3039                 /* Fill in the correct value in the ID field */
3040                 pmc->pm_id = PMC_ID_MAKE_ID(cpu,mode,pa.pm_class,n);
3041
3042                 PMCDBG(PMC,ALL,2, "ev=%d class=%d mode=%d n=%d -> pmcid=%x",
3043                     pmc->pm_event, pa.pm_class, mode, n, pmc->pm_id);
3044
3045                 /* Process mode PMCs with logging enabled need log files */
3046                 if (pmc->pm_flags & (PMC_F_LOG_PROCEXIT | PMC_F_LOG_PROCCSW))
3047                         pmc->pm_flags |= PMC_F_NEEDS_LOGFILE;
3048
3049                 /* All system mode sampling PMCs require a log file */
3050                 if (PMC_IS_SAMPLING_MODE(mode) && PMC_IS_SYSTEM_MODE(mode))
3051                         pmc->pm_flags |= PMC_F_NEEDS_LOGFILE;
3052
3053                 /*
3054                  * Configure global pmc's immediately
3055                  */
3056
3057                 if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pmc))) {
3058
3059                         pmc_save_cpu_binding(&pb);
3060                         pmc_select_cpu(cpu);
3061
3062                         phw = pmc_pcpu[cpu]->pc_hwpmcs[n];
3063
3064                         if ((phw->phw_state & PMC_PHW_FLAG_IS_ENABLED) == 0 ||
3065                             (error = md->pmd_config_pmc(cpu, n, pmc)) != 0) {
3066                                 (void) md->pmd_release_pmc(cpu, n, pmc);
3067                                 pmc_destroy_pmc_descriptor(pmc);
3068                                 FREE(pmc, M_PMC);
3069                                 pmc = NULL;
3070                                 pmc_restore_cpu_binding(&pb);
3071                                 error = EPERM;
3072                                 break;
3073                         }
3074
3075                         pmc_restore_cpu_binding(&pb);
3076                 }
3077
3078                 pmc->pm_state    = PMC_STATE_ALLOCATED;
3079
3080                 /*
3081                  * mark row disposition
3082                  */
3083
3084                 if (PMC_IS_SYSTEM_MODE(mode))
3085                         PMC_MARK_ROW_STANDALONE(n);
3086                 else
3087                         PMC_MARK_ROW_THREAD(n);
3088
3089                 /*
3090                  * Register this PMC with the current thread as its owner.
3091                  */
3092
3093                 if ((error =
3094                     pmc_register_owner(curthread->td_proc, pmc)) != 0) {
3095                         pmc_release_pmc_descriptor(pmc);
3096                         FREE(pmc, M_PMC);
3097                         pmc = NULL;
3098                         break;
3099                 }
3100
3101                 /*
3102                  * Return the allocated index.
3103                  */
3104
3105                 pa.pm_pmcid = pmc->pm_id;
3106
3107                 error = copyout(&pa, arg, sizeof(pa));
3108         }
3109         break;
3110
3111
3112         /*
3113          * Attach a PMC to a process.
3114          */
3115
3116         case PMC_OP_PMCATTACH:
3117         {
3118                 struct pmc *pm;
3119                 struct proc *p;
3120                 struct pmc_op_pmcattach a;
3121
3122                 sx_assert(&pmc_sx, SX_XLOCKED);
3123
3124                 if ((error = copyin(arg, &a, sizeof(a))) != 0)
3125                         break;
3126
3127                 if (a.pm_pid < 0) {
3128                         error = EINVAL;
3129                         break;
3130                 } else if (a.pm_pid == 0)
3131                         a.pm_pid = td->td_proc->p_pid;
3132
3133                 if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
3134                         break;
3135
3136                 if (PMC_IS_SYSTEM_MODE(PMC_TO_MODE(pm))) {
3137                         error = EINVAL;
3138                         break;
3139                 }
3140
3141                 /* PMCs may be (re)attached only when allocated or stopped */
3142                 if (pm->pm_state == PMC_STATE_RUNNING) {
3143                         error = EBUSY;
3144                         break;
3145                 } else if (pm->pm_state != PMC_STATE_ALLOCATED &&
3146                     pm->pm_state != PMC_STATE_STOPPED) {
3147                         error = EINVAL;
3148                         break;
3149                 }
3150
3151                 /* lookup pid */
3152                 if ((p = pfind(a.pm_pid)) == NULL) {
3153                         error = ESRCH;
3154                         break;
3155                 }
3156
3157                 /*
3158                  * Ignore processes that are working on exiting.
3159                  */
3160                 if (p->p_flag & P_WEXIT) {
3161                         error = ESRCH;
3162                         PROC_UNLOCK(p); /* pfind() returns a locked process */
3163                         break;
3164                 }
3165
3166                 /*
3167                  * we are allowed to attach a PMC to a process if
3168                  * we can debug it.
3169                  */
3170                 error = p_candebug(curthread, p);
3171
3172                 PROC_UNLOCK(p);
3173
3174                 if (error == 0)
3175                         error = pmc_attach_process(p, pm);
3176         }
3177         break;
3178
3179
3180         /*
3181          * Detach an attached PMC from a process.
3182          */
3183
3184         case PMC_OP_PMCDETACH:
3185         {
3186                 struct pmc *pm;
3187                 struct proc *p;
3188                 struct pmc_op_pmcattach a;
3189
3190                 if ((error = copyin(arg, &a, sizeof(a))) != 0)
3191                         break;
3192
3193                 if (a.pm_pid < 0) {
3194                         error = EINVAL;
3195                         break;
3196                 } else if (a.pm_pid == 0)
3197                         a.pm_pid = td->td_proc->p_pid;
3198
3199                 if ((error = pmc_find_pmc(a.pm_pmc, &pm)) != 0)
3200                         break;
3201
3202                 if ((p = pfind(a.pm_pid)) == NULL) {
3203                         error = ESRCH;
3204                         break;
3205                 }
3206
3207                 /*
3208                  * Treat processes that are in the process of exiting
3209                  * as if they were not present.
3210                  */
3211
3212                 if (p->p_flag & P_WEXIT)
3213                         error = ESRCH;
3214
3215                 PROC_UNLOCK(p); /* pfind() returns a locked process */
3216
3217                 if (error == 0)
3218                         error = pmc_detach_process(p, pm);
3219         }
3220         break;
3221
3222
3223         /*
3224          * Retrieve the MSR number associated with the counter
3225          * 'pmc_id'.  This allows processes to directly use RDPMC
3226          * instructions to read their PMCs, without the overhead of a
3227          * system call.
3228          */
3229
3230         case PMC_OP_PMCGETMSR:
3231         {
3232                 int ri;
3233                 struct pmc      *pm;
3234                 struct pmc_target *pt;
3235                 struct pmc_op_getmsr gm;
3236
3237                 PMC_DOWNGRADE_SX();
3238
3239                 /* CPU has no 'GETMSR' support */
3240                 if (md->pmd_get_msr == NULL) {
3241                         error = ENOSYS;
3242                         break;
3243                 }
3244
3245                 if ((error = copyin(arg, &gm, sizeof(gm))) != 0)
3246                         break;
3247
3248                 if ((error = pmc_find_pmc(gm.pm_pmcid, &pm)) != 0)
3249                         break;
3250
3251                 /*
3252                  * The allocated PMC has to be a process virtual PMC,
3253                  * i.e., of type MODE_T[CS].  Global PMCs can only be
3254                  * read using the PMCREAD operation since they may be
3255                  * allocated on a different CPU than the one we could
3256                  * be running on at the time of the RDPMC instruction.
3257                  *
3258                  * The GETMSR operation is not allowed for PMCs that
3259                  * are inherited across processes.
3260                  */
3261
3262                 if (!PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)) ||
3263                     (pm->pm_flags & PMC_F_DESCENDANTS)) {
3264                         error = EINVAL;
3265                         break;
3266                 }
3267
3268                 /*
3269                  * It only makes sense to use a RDPMC (or its
3270                  * equivalent instruction on non-x86 architectures) on
3271                  * a process that has allocated and attached a PMC to
3272                  * itself.  Conversely the PMC is only allowed to have
3273                  * one process attached to it -- its owner.
3274                  */
3275
3276                 if ((pt = LIST_FIRST(&pm->pm_targets)) == NULL ||
3277                     LIST_NEXT(pt, pt_next) != NULL ||
3278                     pt->pt_process->pp_proc != pm->pm_owner->po_owner) {
3279                         error = EINVAL;
3280                         break;
3281                 }
3282
3283                 ri = PMC_TO_ROWINDEX(pm);
3284
3285                 if ((error = (*md->pmd_get_msr)(ri, &gm.pm_msr)) < 0)
3286                         break;
3287
3288                 if ((error = copyout(&gm, arg, sizeof(gm))) < 0)
3289                         break;
3290
3291                 /*
3292                  * Mark our process as using MSRs.  Update machine
3293                  * state using a forced context switch.
3294                  */
3295
3296                 pt->pt_process->pp_flags |= PMC_PP_ENABLE_MSR_ACCESS;
3297                 pmc_force_context_switch();
3298
3299         }
3300         break;
3301
3302         /*
3303          * Release an allocated PMC
3304          */
3305
3306         case PMC_OP_PMCRELEASE:
3307         {
3308                 pmc_id_t pmcid;
3309                 struct pmc *pm;
3310                 struct pmc_owner *po;
3311                 struct pmc_op_simple sp;
3312
3313                 /*
3314                  * Find PMC pointer for the named PMC.
3315                  *
3316                  * Use pmc_release_pmc_descriptor() to switch off the
3317                  * PMC, remove all its target threads, and remove the
3318                  * PMC from its owner's list.
3319                  *
3320                  * Remove the owner record if this is the last PMC
3321                  * owned.
3322                  *
3323                  * Free up space.
3324                  */
3325
3326                 if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
3327                         break;
3328
3329                 pmcid = sp.pm_pmcid;
3330
3331                 if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
3332                         break;
3333
3334                 po = pm->pm_owner;
3335                 pmc_release_pmc_descriptor(pm);
3336                 pmc_maybe_remove_owner(po);
3337
3338                 FREE(pm, M_PMC);
3339         }
3340         break;
3341
3342
3343         /*
3344          * Read and/or write a PMC.
3345          */
3346
3347         case PMC_OP_PMCRW:
3348         {
3349                 uint32_t cpu, ri;
3350                 struct pmc *pm;
3351                 struct pmc_op_pmcrw *pprw;
3352                 struct pmc_op_pmcrw prw;
3353                 struct pmc_binding pb;
3354                 pmc_value_t oldvalue;
3355
3356                 PMC_DOWNGRADE_SX();
3357
3358                 if ((error = copyin(arg, &prw, sizeof(prw))) != 0)
3359                         break;
3360
3361                 ri = 0;
3362                 PMCDBG(PMC,OPS,1, "rw id=%d flags=0x%x", prw.pm_pmcid,
3363                     prw.pm_flags);
3364
3365                 /* must have at least one flag set */
3366                 if ((prw.pm_flags & (PMC_F_OLDVALUE|PMC_F_NEWVALUE)) == 0) {
3367                         error = EINVAL;
3368                         break;
3369                 }
3370
3371                 /* locate pmc descriptor */
3372                 if ((error = pmc_find_pmc(prw.pm_pmcid, &pm)) != 0)
3373                         break;
3374
3375                 /* Can't read a PMC that hasn't been started. */
3376                 if (pm->pm_state != PMC_STATE_ALLOCATED &&
3377                     pm->pm_state != PMC_STATE_STOPPED &&
3378                     pm->pm_state != PMC_STATE_RUNNING) {
3379                         error = EINVAL;
3380                         break;
3381                 }
3382
3383                 /* writing a new value is allowed only for 'STOPPED' pmcs */
3384                 if (pm->pm_state == PMC_STATE_RUNNING &&
3385                     (prw.pm_flags & PMC_F_NEWVALUE)) {
3386                         error = EBUSY;
3387                         break;
3388                 }
3389
3390                 if (PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm))) {
3391
3392                         /*
3393                          * If this PMC is attached to its owner (i.e.,
3394                          * the process requesting this operation) and
3395                          * is running, then attempt to get an
3396                          * upto-date reading from hardware for a READ.
3397                          * Writes are only allowed when the PMC is
3398                          * stopped, so only update the saved value
3399                          * field.
3400                          *
3401                          * If the PMC is not running, or is not
3402                          * attached to its owner, read/write to the
3403                          * savedvalue field.
3404                          */
3405
3406                         ri = PMC_TO_ROWINDEX(pm);
3407
3408                         mtx_pool_lock_spin(pmc_mtxpool, pm);
3409                         cpu = curthread->td_oncpu;
3410
3411                         if (prw.pm_flags & PMC_F_OLDVALUE) {
3412                                 if ((pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) &&
3413                                     (pm->pm_state == PMC_STATE_RUNNING))
3414                                         error = (*md->pmd_read_pmc)(cpu, ri,
3415                                             &oldvalue);
3416                                 else
3417                                         oldvalue = pm->pm_gv.pm_savedvalue;
3418                         }
3419                         if (prw.pm_flags & PMC_F_NEWVALUE)
3420                                 pm->pm_gv.pm_savedvalue = prw.pm_value;
3421
3422                         mtx_pool_unlock_spin(pmc_mtxpool, pm);
3423
3424                 } else { /* System mode PMCs */
3425                         cpu = PMC_TO_CPU(pm);
3426                         ri  = PMC_TO_ROWINDEX(pm);
3427
3428                         if (pmc_cpu_is_disabled(cpu)) {
3429                                 error = ENXIO;
3430                                 break;
3431                         }
3432
3433                         /* move this thread to CPU 'cpu' */
3434                         pmc_save_cpu_binding(&pb);
3435                         pmc_select_cpu(cpu);
3436
3437                         critical_enter();
3438                         /* save old value */
3439                         if (prw.pm_flags & PMC_F_OLDVALUE)
3440                                 if ((error = (*md->pmd_read_pmc)(cpu, ri,
3441                                          &oldvalue)))
3442                                         goto error;
3443                         /* write out new value */
3444                         if (prw.pm_flags & PMC_F_NEWVALUE)
3445                                 error = (*md->pmd_write_pmc)(cpu, ri,
3446                                     prw.pm_value);
3447                 error:
3448                         critical_exit();
3449                         pmc_restore_cpu_binding(&pb);
3450                         if (error)
3451                                 break;
3452                 }
3453
3454                 pprw = (struct pmc_op_pmcrw *) arg;
3455
3456 #ifdef  DEBUG
3457                 if (prw.pm_flags & PMC_F_NEWVALUE)
3458                         PMCDBG(PMC,OPS,2, "rw id=%d new %jx -> old %jx",
3459                             ri, prw.pm_value, oldvalue);
3460                 else if (prw.pm_flags & PMC_F_OLDVALUE)
3461                         PMCDBG(PMC,OPS,2, "rw id=%d -> old %jx", ri, oldvalue);
3462 #endif
3463
3464                 /* return old value if requested */
3465                 if (prw.pm_flags & PMC_F_OLDVALUE)
3466                         if ((error = copyout(&oldvalue, &pprw->pm_value,
3467                                  sizeof(prw.pm_value))))
3468                                 break;
3469
3470         }
3471         break;
3472
3473
3474         /*
3475          * Set the sampling rate for a sampling mode PMC and the
3476          * initial count for a counting mode PMC.
3477          */
3478
3479         case PMC_OP_PMCSETCOUNT:
3480         {
3481                 struct pmc *pm;
3482                 struct pmc_op_pmcsetcount sc;
3483
3484                 PMC_DOWNGRADE_SX();
3485
3486                 if ((error = copyin(arg, &sc, sizeof(sc))) != 0)
3487                         break;
3488
3489                 if ((error = pmc_find_pmc(sc.pm_pmcid, &pm)) != 0)
3490                         break;
3491
3492                 if (pm->pm_state == PMC_STATE_RUNNING) {
3493                         error = EBUSY;
3494                         break;
3495                 }
3496
3497                 if (PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)))
3498                         pm->pm_sc.pm_reloadcount = sc.pm_count;
3499                 else
3500                         pm->pm_sc.pm_initial = sc.pm_count;
3501         }
3502         break;
3503
3504
3505         /*
3506          * Start a PMC.
3507          */
3508
3509         case PMC_OP_PMCSTART:
3510         {
3511                 pmc_id_t pmcid;
3512                 struct pmc *pm;
3513                 struct pmc_op_simple sp;
3514
3515                 sx_assert(&pmc_sx, SX_XLOCKED);
3516
3517                 if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
3518                         break;
3519
3520                 pmcid = sp.pm_pmcid;
3521
3522                 if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
3523                         break;
3524
3525                 KASSERT(pmcid == pm->pm_id,
3526                     ("[pmc,%d] pmcid %x != id %x", __LINE__,
3527                         pm->pm_id, pmcid));
3528
3529                 if (pm->pm_state == PMC_STATE_RUNNING) /* already running */
3530                         break;
3531                 else if (pm->pm_state != PMC_STATE_STOPPED &&
3532                     pm->pm_state != PMC_STATE_ALLOCATED) {
3533                         error = EINVAL;
3534                         break;
3535                 }
3536
3537                 error = pmc_start(pm);
3538         }
3539         break;
3540
3541
3542         /*
3543          * Stop a PMC.
3544          */
3545
3546         case PMC_OP_PMCSTOP:
3547         {
3548                 pmc_id_t pmcid;
3549                 struct pmc *pm;
3550                 struct pmc_op_simple sp;
3551
3552                 PMC_DOWNGRADE_SX();
3553
3554                 if ((error = copyin(arg, &sp, sizeof(sp))) != 0)
3555                         break;
3556
3557                 pmcid = sp.pm_pmcid;
3558
3559                 /*
3560                  * Mark the PMC as inactive and invoke the MD stop
3561                  * routines if needed.
3562                  */
3563
3564                 if ((error = pmc_find_pmc(pmcid, &pm)) != 0)
3565                         break;
3566
3567                 KASSERT(pmcid == pm->pm_id,
3568                     ("[pmc,%d] pmc id %x != pmcid %x", __LINE__,
3569                         pm->pm_id, pmcid));
3570
3571                 if (pm->pm_state == PMC_STATE_STOPPED) /* already stopped */
3572                         break;
3573                 else if (pm->pm_state != PMC_STATE_RUNNING) {
3574                         error = EINVAL;
3575                         break;
3576                 }
3577
3578                 error = pmc_stop(pm);
3579         }
3580         break;
3581
3582
3583         /*
3584          * Write a user supplied value to the log file.
3585          */
3586
3587         case PMC_OP_WRITELOG:
3588         {
3589                 struct pmc_op_writelog wl;
3590                 struct pmc_owner *po;
3591
3592                 PMC_DOWNGRADE_SX();
3593
3594                 if ((error = copyin(arg, &wl, sizeof(wl))) != 0)
3595                         break;
3596
3597                 if ((po = pmc_find_owner_descriptor(td->td_proc)) == NULL) {
3598                         error = EINVAL;
3599                         break;
3600                 }
3601
3602                 if ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0) {
3603                         error = EINVAL;
3604                         break;
3605                 }
3606
3607                 error = pmclog_process_userlog(po, &wl);
3608         }
3609         break;
3610
3611
3612         default:
3613                 error = EINVAL;
3614                 break;
3615         }
3616
3617         if (is_sx_downgraded)
3618                 sx_sunlock(&pmc_sx);
3619         else
3620                 sx_xunlock(&pmc_sx);
3621
3622         if (error)
3623                 atomic_add_int(&pmc_stats.pm_syscall_errors, 1);
3624
3625         PICKUP_GIANT();
3626
3627         return error;
3628 }
3629
3630 /*
3631  * Helper functions
3632  */
3633
3634
3635 /*
3636  * Interrupt processing.
3637  *
3638  * Find a free slot in the per-cpu array of PC samples and write the
3639  * current (PMC,PID,PC) triple to it.  If an event was successfully
3640  * added, a bit is set in mask 'pmc_cpumask' denoting that the
3641  * DO_SAMPLES hook needs to be invoked from the clock handler.
3642  *
3643  * This function is meant to be called from an NMI handler.  It cannot
3644  * use any of the locking primitives supplied by the OS.
3645  */
3646
3647 int
3648 pmc_process_interrupt(int cpu, struct pmc *pm, uintfptr_t pc, int usermode)
3649 {
3650         int error, ri;
3651         struct thread *td;
3652         struct pmc_sample *ps;
3653         struct pmc_samplebuffer *psb;
3654
3655         error = 0;
3656         ri = PMC_TO_ROWINDEX(pm);
3657
3658         psb = pmc_pcpu[cpu]->pc_sb;
3659
3660         ps = psb->ps_write;
3661         if (ps->ps_pc) {        /* in use, reader hasn't caught up */
3662                 pm->pm_stalled = 1;
3663                 atomic_add_int(&pmc_stats.pm_intr_bufferfull, 1);
3664                 PMCDBG(SAM,INT,1,"(spc) cpu=%d pm=%p pc=%jx um=%d wr=%d rd=%d",
3665                     cpu, pm, (uint64_t) pc, usermode,
3666                     (int) (psb->ps_write - psb->ps_samples),
3667                     (int) (psb->ps_read - psb->ps_samples));
3668                 error = ENOMEM;
3669                 goto done;
3670         }
3671
3672         /* fill in entry */
3673         PMCDBG(SAM,INT,1,"cpu=%d pm=%p pc=%jx um=%d wr=%d rd=%d", cpu, pm,
3674             (uint64_t) pc, usermode,
3675             (int) (psb->ps_write - psb->ps_samples),
3676             (int) (psb->ps_read - psb->ps_samples));
3677
3678         atomic_add_rel_32(&pm->pm_runcount, 1);         /* hold onto PMC */
3679         ps->ps_pmc = pm;
3680         if ((td = curthread) && td->td_proc)
3681                 ps->ps_pid = td->td_proc->p_pid;
3682         else
3683                 ps->ps_pid = -1;
3684         ps->ps_usermode = usermode;
3685         ps->ps_pc = pc;         /* mark entry as in use */
3686
3687         /* increment write pointer, modulo ring buffer size */
3688         ps++;
3689         if (ps == psb->ps_fence)
3690                 psb->ps_write = psb->ps_samples;
3691         else
3692                 psb->ps_write = ps;
3693
3694  done:
3695         /* mark CPU as needing processing */
3696         atomic_set_rel_int(&pmc_cpumask, (1 << cpu));
3697
3698         return error;
3699 }
3700
3701
3702 /*
3703  * Process saved PC samples.
3704  */
3705
3706 static void
3707 pmc_process_samples(int cpu)
3708 {
3709         int n, ri;
3710         struct pmc *pm;
3711         struct thread *td;
3712         struct pmc_owner *po;
3713         struct pmc_sample *ps;
3714         struct pmc_samplebuffer *psb;
3715
3716         KASSERT(PCPU_GET(cpuid) == cpu,
3717             ("[pmc,%d] not on the correct CPU pcpu=%d cpu=%d", __LINE__,
3718                 PCPU_GET(cpuid), cpu));
3719
3720         psb = pmc_pcpu[cpu]->pc_sb;
3721
3722         for (n = 0; n < pmc_nsamples; n++) { /* bound on #iterations */
3723
3724                 ps = psb->ps_read;
3725                 if (ps->ps_pc == (uintfptr_t) 0)        /* no data */
3726                         break;
3727
3728                 pm = ps->ps_pmc;
3729                 po = pm->pm_owner;
3730
3731                 KASSERT(PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)),
3732                     ("[pmc,%d] pmc=%p non-sampling mode=%d", __LINE__,
3733                         pm, PMC_TO_MODE(pm)));
3734
3735                 /* Ignore PMCs that have been switched off */
3736                 if (pm->pm_state != PMC_STATE_RUNNING)
3737                         goto entrydone;
3738
3739                 PMCDBG(SAM,OPS,1,"cpu=%d pm=%p pc=%jx um=%d wr=%d rd=%d", cpu,
3740                     pm, (uint64_t) ps->ps_pc, ps->ps_usermode,
3741                     (int) (psb->ps_write - psb->ps_samples),
3742                     (int) (psb->ps_read - psb->ps_samples));
3743
3744                 /*
3745                  * If this is a process-mode PMC that is attached to
3746                  * its owner, and if the PC is in user mode, update
3747                  * profiling statistics like timer-based profiling
3748                  * would have done.
3749                  */
3750                 if (pm->pm_flags & PMC_F_ATTACHED_TO_OWNER) {
3751                         if (ps->ps_usermode) {
3752                                 td = FIRST_THREAD_IN_PROC(po->po_owner);
3753                                 addupc_intr(td, ps->ps_pc, 1);
3754                         }
3755                         goto entrydone;
3756                 }
3757
3758                 /*
3759                  * Otherwise, this is either a sampling mode PMC that
3760                  * is attached to a different process than its owner,
3761                  * or a system-wide sampling PMC.  Dispatch a log
3762                  * entry to the PMC's owner process.
3763                  */
3764
3765                 pmclog_process_pcsample(pm, ps);
3766
3767         entrydone:
3768                 ps->ps_pc = (uintfptr_t) 0;     /* mark entry as free */
3769                 atomic_subtract_rel_32(&pm->pm_runcount, 1);
3770
3771                 /* increment read pointer, modulo sample size */
3772                 if (++ps == psb->ps_fence)
3773                         psb->ps_read = psb->ps_samples;
3774                 else
3775                         psb->ps_read = ps;
3776         }
3777
3778         atomic_add_int(&pmc_stats.pm_log_sweeps, 1);
3779
3780         /* Do not re-enable stalled PMCs if we failed to process any samples */
3781         if (n == 0)
3782                 return;
3783
3784         /*
3785          * Restart any stalled sampling PMCs on this CPU.
3786          *
3787          * If the NMI handler sets the pm_stalled field of a PMC after
3788          * the check below, we'll end up processing the stalled PMC at
3789          * the next hardclock tick.
3790          */
3791         for (n = 0; n < md->pmd_npmc; n++) {
3792                 (void) (*md->pmd_get_config)(cpu,n,&pm);
3793                 if (pm == NULL ||                        /* !cfg'ed */
3794                     pm->pm_state != PMC_STATE_RUNNING || /* !active */
3795                     !PMC_IS_SAMPLING_MODE(PMC_TO_MODE(pm)) || /* !sampling */
3796                     pm->pm_stalled == 0) /* !stalled */
3797                         continue;
3798
3799                 pm->pm_stalled = 0;
3800                 ri = PMC_TO_ROWINDEX(pm);
3801                 (*md->pmd_start_pmc)(cpu, ri);
3802         }
3803 }
3804
3805 /*
3806  * Event handlers.
3807  */
3808
3809 /*
3810  * Handle a process exit.
3811  *
3812  * Remove this process from all hash tables.  If this process
3813  * owned any PMCs, turn off those PMCs and deallocate them,
3814  * removing any associations with target processes.
3815  *
3816  * This function will be called by the last 'thread' of a
3817  * process.
3818  *
3819  * XXX This eventhandler gets called early in the exit process.
3820  * Consider using a 'hook' invocation from thread_exit() or equivalent
3821  * spot.  Another negative is that kse_exit doesn't seem to call
3822  * exit1() [??].
3823  *
3824  */
3825
3826 static void
3827 pmc_process_exit(void *arg __unused, struct proc *p)
3828 {
3829         int is_using_hwpmcs;
3830         int cpu;
3831         unsigned int ri;
3832         struct pmc *pm;
3833         struct pmc_process *pp;
3834         struct pmc_owner *po;
3835         pmc_value_t newvalue, tmp;
3836
3837         PROC_LOCK(p);
3838         is_using_hwpmcs = p->p_flag & P_HWPMC;
3839         PROC_UNLOCK(p);
3840
3841         /*
3842          * Log a sysexit event to all SS PMC owners.
3843          */
3844         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
3845             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
3846                     pmclog_process_sysexit(po, p->p_pid);
3847
3848         if (!is_using_hwpmcs)
3849                 return;
3850
3851         PMC_GET_SX_XLOCK();
3852         PMCDBG(PRC,EXT,1,"process-exit proc=%p (%d, %s)", p, p->p_pid,
3853             p->p_comm);
3854
3855         /*
3856          * Since this code is invoked by the last thread in an exiting
3857          * process, we would have context switched IN at some prior
3858          * point.  However, with PREEMPTION, kernel mode context
3859          * switches may happen any time, so we want to disable a
3860          * context switch OUT till we get any PMCs targetting this
3861          * process off the hardware.
3862          *
3863          * We also need to atomically remove this process'
3864          * entry from our target process hash table, using
3865          * PMC_FLAG_REMOVE.
3866          */
3867         PMCDBG(PRC,EXT,1, "process-exit proc=%p (%d, %s)", p, p->p_pid,
3868             p->p_comm);
3869
3870         critical_enter(); /* no preemption */
3871
3872         cpu = curthread->td_oncpu;
3873
3874         if ((pp = pmc_find_process_descriptor(p,
3875                  PMC_FLAG_REMOVE)) != NULL) {
3876
3877                 PMCDBG(PRC,EXT,2,
3878                     "process-exit proc=%p pmc-process=%p", p, pp);
3879
3880                 /*
3881                  * The exiting process could the target of
3882                  * some PMCs which will be running on
3883                  * currently executing CPU.
3884                  *
3885                  * We need to turn these PMCs off like we
3886                  * would do at context switch OUT time.
3887                  */
3888                 for (ri = 0; ri < md->pmd_npmc; ri++) {
3889
3890                         /*
3891                          * Pick up the pmc pointer from hardware
3892                          * state similar to the CSW_OUT code.
3893                          */
3894                         pm = NULL;
3895                         (void) (*md->pmd_get_config)(cpu, ri, &pm);
3896
3897                         PMCDBG(PRC,EXT,2, "ri=%d pm=%p", ri, pm);
3898
3899                         if (pm == NULL ||
3900                             !PMC_IS_VIRTUAL_MODE(PMC_TO_MODE(pm)))
3901                                 continue;
3902
3903                         PMCDBG(PRC,EXT,2, "ppmcs[%d]=%p pm=%p "
3904                             "state=%d", ri, pp->pp_pmcs[ri].pp_pmc,
3905                             pm, pm->pm_state);
3906
3907                         KASSERT(PMC_TO_ROWINDEX(pm) == ri,
3908                             ("[pmc,%d] ri mismatch pmc(%d) ri(%d)",
3909                                 __LINE__, PMC_TO_ROWINDEX(pm), ri));
3910
3911                         KASSERT(pm == pp->pp_pmcs[ri].pp_pmc,
3912                             ("[pmc,%d] pm %p != pp_pmcs[%d] %p",
3913                                 __LINE__, pm, ri, pp->pp_pmcs[ri].pp_pmc));
3914
3915                         (void) md->pmd_stop_pmc(cpu, ri);
3916
3917                         KASSERT(pm->pm_runcount > 0,
3918                             ("[pmc,%d] bad runcount ri %d rc %d",
3919                                 __LINE__, ri, pm->pm_runcount));
3920
3921                         /* Stop hardware only if it is actually running */
3922                         if (pm->pm_state == PMC_STATE_RUNNING &&
3923                             pm->pm_stalled == 0) {
3924                                 md->pmd_read_pmc(cpu, ri, &newvalue);
3925                                 tmp = newvalue -
3926                                     PMC_PCPU_SAVED(cpu,ri);
3927
3928                                 mtx_pool_lock_spin(pmc_mtxpool, pm);
3929                                 pm->pm_gv.pm_savedvalue += tmp;
3930                                 pp->pp_pmcs[ri].pp_pmcval += tmp;
3931                                 mtx_pool_unlock_spin(pmc_mtxpool, pm);
3932                         }
3933
3934                         atomic_subtract_rel_32(&pm->pm_runcount,1);
3935
3936                         KASSERT((int) pm->pm_runcount >= 0,
3937                             ("[pmc,%d] runcount is %d", __LINE__, ri));
3938
3939                         (void) md->pmd_config_pmc(cpu, ri, NULL);
3940                 }
3941
3942                 /*
3943                  * Inform the MD layer of this pseudo "context switch
3944                  * out"
3945                  */
3946                 (void) md->pmd_switch_out(pmc_pcpu[cpu], pp);
3947
3948                 critical_exit(); /* ok to be pre-empted now */
3949
3950                 /*
3951                  * Unlink this process from the PMCs that are
3952                  * targetting it.  This will send a signal to
3953                  * all PMC owner's whose PMCs are orphaned.
3954                  *
3955                  * Log PMC value at exit time if requested.
3956                  */
3957                 for (ri = 0; ri < md->pmd_npmc; ri++)
3958                         if ((pm = pp->pp_pmcs[ri].pp_pmc) != NULL) {
3959                                 if (pm->pm_flags & PMC_F_NEEDS_LOGFILE &&
3960                                     PMC_IS_COUNTING_MODE(PMC_TO_MODE(pm)))
3961                                         pmclog_process_procexit(pm, pp);
3962                                 pmc_unlink_target_process(pm, pp);
3963                         }
3964                 FREE(pp, M_PMC);
3965
3966         } else
3967                 critical_exit(); /* pp == NULL */
3968
3969
3970         /*
3971          * If the process owned PMCs, free them up and free up
3972          * memory.
3973          */
3974         if ((po = pmc_find_owner_descriptor(p)) != NULL) {
3975                 pmc_remove_owner(po);
3976                 pmc_destroy_owner_descriptor(po);
3977         }
3978
3979         sx_xunlock(&pmc_sx);
3980 }
3981
3982 /*
3983  * Handle a process fork.
3984  *
3985  * If the parent process 'p1' is under HWPMC monitoring, then copy
3986  * over any attached PMCs that have 'do_descendants' semantics.
3987  */
3988
3989 static void
3990 pmc_process_fork(void *arg __unused, struct proc *p1, struct proc *newproc,
3991     int flags)
3992 {
3993         int is_using_hwpmcs;
3994         unsigned int ri;
3995         uint32_t do_descendants;
3996         struct pmc *pm;
3997         struct pmc_owner *po;
3998         struct pmc_process *ppnew, *ppold;
3999
4000         (void) flags;           /* unused parameter */
4001
4002         PROC_LOCK(p1);
4003         is_using_hwpmcs = p1->p_flag & P_HWPMC;
4004         PROC_UNLOCK(p1);
4005
4006         /*
4007          * If there are system-wide sampling PMCs active, we need to
4008          * log all fork events to their owner's logs.
4009          */
4010
4011         LIST_FOREACH(po, &pmc_ss_owners, po_ssnext)
4012             if (po->po_flags & PMC_PO_OWNS_LOGFILE)
4013                     pmclog_process_procfork(po, p1->p_pid, newproc->p_pid);
4014
4015         if (!is_using_hwpmcs)
4016                 return;
4017
4018         PMC_GET_SX_XLOCK();
4019         PMCDBG(PMC,FRK,1, "process-fork proc=%p (%d, %s) -> %p", p1,
4020             p1->p_pid, p1->p_comm, newproc);
4021
4022         /*
4023          * If the parent process (curthread->td_proc) is a
4024          * target of any PMCs, look for PMCs that are to be
4025          * inherited, and link these into the new process
4026          * descriptor.
4027          */
4028         if ((ppold = pmc_find_process_descriptor(curthread->td_proc,
4029                  PMC_FLAG_NONE)) == NULL)
4030                 goto done;              /* nothing to do */
4031
4032         do_descendants = 0;
4033         for (ri = 0; ri < md->pmd_npmc; ri++)
4034                 if ((pm = ppold->pp_pmcs[ri].pp_pmc) != NULL)
4035                         do_descendants |= pm->pm_flags & PMC_F_DESCENDANTS;
4036         if (do_descendants == 0) /* nothing to do */
4037                 goto done;
4038
4039         /* allocate a descriptor for the new process  */
4040         if ((ppnew = pmc_find_process_descriptor(newproc,
4041                  PMC_FLAG_ALLOCATE)) == NULL)
4042                 goto done;
4043
4044         /*
4045          * Run through all PMCs that were targeting the old process
4046          * and which specified F_DESCENDANTS and attach them to the
4047          * new process.
4048          *
4049          * Log the fork event to all owners of PMCs attached to this
4050          * process, if not already logged.
4051          */
4052         for (ri = 0; ri < md->pmd_npmc; ri++)
4053                 if ((pm = ppold->pp_pmcs[ri].pp_pmc) != NULL &&
4054                     (pm->pm_flags & PMC_F_DESCENDANTS)) {
4055                         pmc_link_target_process(pm, ppnew);
4056                         po = pm->pm_owner;
4057                         if (po->po_sscount == 0 &&
4058                             po->po_flags & PMC_PO_OWNS_LOGFILE)
4059                                 pmclog_process_procfork(po, p1->p_pid,
4060                                     newproc->p_pid);
4061                 }
4062
4063         /*
4064          * Now mark the new process as being tracked by this driver.
4065          */
4066         PROC_LOCK(newproc);
4067         newproc->p_flag |= P_HWPMC;
4068         PROC_UNLOCK(newproc);
4069
4070  done:
4071         sx_xunlock(&pmc_sx);
4072 }
4073
4074
4075 /*
4076  * initialization
4077  */
4078
4079 static const char *pmc_name_of_pmcclass[] = {
4080 #undef  __PMC_CLASS
4081 #define __PMC_CLASS(N) #N ,
4082         __PMC_CLASSES()
4083 };
4084
4085 static int
4086 pmc_initialize(void)
4087 {
4088         int cpu, error, n;
4089         struct pmc_binding pb;
4090         struct pmc_samplebuffer *sb;
4091
4092         md = NULL;
4093         error = 0;
4094
4095 #ifdef  DEBUG
4096         /* parse debug flags first */
4097         if (TUNABLE_STR_FETCH(PMC_SYSCTL_NAME_PREFIX "debugflags",
4098                 pmc_debugstr, sizeof(pmc_debugstr)))
4099                 pmc_debugflags_parse(pmc_debugstr,
4100                     pmc_debugstr+strlen(pmc_debugstr));
4101 #endif
4102
4103         PMCDBG(MOD,INI,0, "PMC Initialize (version %x)", PMC_VERSION);
4104
4105         /* check kernel version */
4106         if (pmc_kernel_version != PMC_VERSION) {
4107                 if (pmc_kernel_version == 0)
4108                         printf("hwpmc: this kernel has not been compiled with "
4109                             "'options HWPMC_HOOKS'.\n");
4110                 else
4111                         printf("hwpmc: kernel version (0x%x) does not match "
4112                             "module version (0x%x).\n", pmc_kernel_version,
4113                             PMC_VERSION);
4114                 return EPROGMISMATCH;
4115         }
4116
4117         /*
4118          * check sysctl parameters
4119          */
4120
4121         if (pmc_hashsize <= 0) {
4122                 (void) printf("hwpmc: tunable hashsize=%d must be greater "
4123                     "than zero.\n", pmc_hashsize);
4124                 pmc_hashsize = PMC_HASH_SIZE;
4125         }
4126
4127         if (pmc_nsamples <= 0 || pmc_nsamples > 65535) {
4128                 (void) printf("hwpmc: tunable nsamples=%d out of range.\n",
4129                     pmc_nsamples);
4130                 pmc_nsamples = PMC_NSAMPLES;
4131         }
4132
4133         md = pmc_md_initialize();
4134
4135         if (md == NULL || md->pmd_init == NULL)
4136                 return ENOSYS;
4137
4138         /* allocate space for the per-cpu array */
4139         MALLOC(pmc_pcpu, struct pmc_cpu **, mp_ncpus * sizeof(struct pmc_cpu *),
4140             M_PMC, M_WAITOK|M_ZERO);
4141
4142         /* per-cpu 'saved values' for managing process-mode PMCs */
4143         MALLOC(pmc_pcpu_saved, pmc_value_t *,
4144             sizeof(pmc_value_t) * mp_ncpus * md->pmd_npmc, M_PMC, M_WAITOK);
4145
4146         /* perform cpu dependent initialization */
4147         pmc_save_cpu_binding(&pb);
4148         for (cpu = 0; cpu < mp_ncpus; cpu++) {
4149                 if (pmc_cpu_is_disabled(cpu))
4150                         continue;
4151                 pmc_select_cpu(cpu);
4152                 if ((error = md->pmd_init(cpu)) != 0)
4153                         break;
4154         }
4155         pmc_restore_cpu_binding(&pb);
4156
4157         if (error != 0)
4158                 return error;
4159
4160         /* allocate space for the sample array */
4161         for (cpu = 0; cpu < mp_ncpus; cpu++) {
4162                 if (pmc_cpu_is_disabled(cpu))
4163                         continue;
4164                 MALLOC(sb, struct pmc_samplebuffer *,
4165                     sizeof(struct pmc_samplebuffer) +
4166                     pmc_nsamples * sizeof(struct pmc_sample), M_PMC,
4167                     M_WAITOK|M_ZERO);
4168
4169                 sb->ps_read = sb->ps_write = sb->ps_samples;
4170                 sb->ps_fence = sb->ps_samples + pmc_nsamples;
4171                 KASSERT(pmc_pcpu[cpu] != NULL,
4172                     ("[pmc,%d] cpu=%d Null per-cpu data", __LINE__, cpu));
4173
4174                 pmc_pcpu[cpu]->pc_sb = sb;
4175         }
4176
4177         /* allocate space for the row disposition array */
4178         pmc_pmcdisp = malloc(sizeof(enum pmc_mode) * md->pmd_npmc,
4179             M_PMC, M_WAITOK|M_ZERO);
4180
4181         KASSERT(pmc_pmcdisp != NULL,
4182             ("[pmc,%d] pmcdisp allocation returned NULL", __LINE__));
4183
4184         /* mark all PMCs as available */
4185         for (n = 0; n < (int) md->pmd_npmc; n++)
4186                 PMC_MARK_ROW_FREE(n);
4187
4188         /* allocate thread hash tables */
4189         pmc_ownerhash = hashinit(pmc_hashsize, M_PMC,
4190             &pmc_ownerhashmask);
4191
4192         pmc_processhash = hashinit(pmc_hashsize, M_PMC,
4193             &pmc_processhashmask);
4194         mtx_init(&pmc_processhash_mtx, "pmc-process-hash", "pmc-leaf",
4195             MTX_SPIN);
4196
4197         LIST_INIT(&pmc_ss_owners);
4198         pmc_ss_count = 0;
4199
4200         /* allocate a pool of spin mutexes */
4201         pmc_mtxpool = mtx_pool_create("pmc-leaf", pmc_mtxpool_size,
4202             MTX_SPIN);
4203
4204         PMCDBG(MOD,INI,1, "pmc_ownerhash=%p, mask=0x%lx "
4205             "targethash=%p mask=0x%lx", pmc_ownerhash, pmc_ownerhashmask,
4206             pmc_processhash, pmc_processhashmask);
4207
4208         /* register process {exit,fork,exec} handlers */
4209         pmc_exit_tag = EVENTHANDLER_REGISTER(process_exit,
4210             pmc_process_exit, NULL, EVENTHANDLER_PRI_ANY);
4211         pmc_fork_tag = EVENTHANDLER_REGISTER(process_fork,
4212             pmc_process_fork, NULL, EVENTHANDLER_PRI_ANY);
4213
4214         /* initialize logging */
4215         pmclog_initialize();
4216
4217         /* set hook functions */
4218         pmc_intr = md->pmd_intr;
4219         pmc_hook = pmc_hook_handler;
4220
4221         if (error == 0) {
4222                 printf(PMC_MODULE_NAME ":");
4223                 for (n = 0; n < (int) md->pmd_nclass; n++) {
4224                         printf(" %s/%d/0x%b",
4225                             pmc_name_of_pmcclass[md->pmd_classes[n].pm_class],
4226                             md->pmd_nclasspmcs[n],
4227                             md->pmd_classes[n].pm_caps,
4228                             "\20"
4229                             "\1INT\2USR\3SYS\4EDG\5THR"
4230                             "\6REA\7WRI\10INV\11QUA\12PRC"
4231                             "\13TAG\14CSC");
4232                 }
4233                 printf("\n");
4234         }
4235
4236         return error;
4237 }
4238
4239 /* prepare to be unloaded */
4240 static void
4241 pmc_cleanup(void)
4242 {
4243         int cpu;
4244         struct pmc_ownerhash *ph;
4245         struct pmc_owner *po, *tmp;
4246         struct pmc_binding pb;
4247 #ifdef  DEBUG
4248         struct pmc_processhash *prh;
4249 #endif
4250
4251         PMCDBG(MOD,INI,0, "%s", "cleanup");
4252
4253         /* switch off sampling */
4254         atomic_store_rel_int(&pmc_cpumask, 0);
4255         pmc_intr = NULL;
4256
4257         sx_xlock(&pmc_sx);
4258         if (pmc_hook == NULL) { /* being unloaded already */
4259                 sx_xunlock(&pmc_sx);
4260                 return;
4261         }
4262
4263         pmc_hook = NULL; /* prevent new threads from entering module */
4264
4265         /* deregister event handlers */
4266         EVENTHANDLER_DEREGISTER(process_fork, pmc_fork_tag);
4267         EVENTHANDLER_DEREGISTER(process_exit, pmc_exit_tag);
4268
4269         /* send SIGBUS to all owner threads, free up allocations */
4270         if (pmc_ownerhash)
4271                 for (ph = pmc_ownerhash;
4272                      ph <= &pmc_ownerhash[pmc_ownerhashmask];
4273                      ph++) {
4274                         LIST_FOREACH_SAFE(po, ph, po_next, tmp) {
4275                                 pmc_remove_owner(po);
4276
4277                                 /* send SIGBUS to owner processes */
4278                                 PMCDBG(MOD,INI,2, "cleanup signal proc=%p "
4279                                     "(%d, %s)", po->po_owner,
4280                                     po->po_owner->p_pid,
4281                                     po->po_owner->p_comm);
4282
4283                                 PROC_LOCK(po->po_owner);
4284                                 psignal(po->po_owner, SIGBUS);
4285                                 PROC_UNLOCK(po->po_owner);
4286
4287                                 pmc_destroy_owner_descriptor(po);
4288                         }
4289                 }
4290
4291         /* reclaim allocated data structures */
4292         if (pmc_mtxpool)
4293                 mtx_pool_destroy(&pmc_mtxpool);
4294
4295         mtx_destroy(&pmc_processhash_mtx);
4296         if (pmc_processhash) {
4297 #ifdef  DEBUG
4298                 struct pmc_process *pp;
4299
4300                 PMCDBG(MOD,INI,3, "%s", "destroy process hash");
4301                 for (prh = pmc_processhash;
4302                      prh <= &pmc_processhash[pmc_processhashmask];
4303                      prh++)
4304                         LIST_FOREACH(pp, prh, pp_next)
4305                             PMCDBG(MOD,INI,3, "pid=%d", pp->pp_proc->p_pid);
4306 #endif
4307
4308                 hashdestroy(pmc_processhash, M_PMC, pmc_processhashmask);
4309                 pmc_processhash = NULL;
4310         }
4311
4312         if (pmc_ownerhash) {
4313                 PMCDBG(MOD,INI,3, "%s", "destroy owner hash");
4314                 hashdestroy(pmc_ownerhash, M_PMC, pmc_ownerhashmask);
4315                 pmc_ownerhash = NULL;
4316         }
4317
4318         KASSERT(LIST_EMPTY(&pmc_ss_owners),
4319             ("[pmc,%d] Global SS owner list not empty", __LINE__));
4320         KASSERT(pmc_ss_count == 0,
4321             ("[pmc,%d] Global SS count not empty", __LINE__));
4322
4323         /* free the per-cpu sample buffers */
4324         for (cpu = 0; cpu < mp_ncpus; cpu++) {
4325                 if (pmc_cpu_is_disabled(cpu))
4326                         continue;
4327                 KASSERT(pmc_pcpu[cpu]->pc_sb != NULL,
4328                     ("[pmc,%d] Null cpu sample buffer cpu=%d", __LINE__,
4329                         cpu));
4330                 FREE(pmc_pcpu[cpu]->pc_sb, M_PMC);
4331                 pmc_pcpu[cpu]->pc_sb = NULL;
4332         }
4333
4334         /* do processor dependent cleanup */
4335         PMCDBG(MOD,INI,3, "%s", "md cleanup");
4336         if (md) {
4337                 pmc_save_cpu_binding(&pb);
4338                 for (cpu = 0; cpu < mp_ncpus; cpu++) {
4339                         PMCDBG(MOD,INI,1,"pmc-cleanup cpu=%d pcs=%p",
4340                             cpu, pmc_pcpu[cpu]);
4341                         if (pmc_cpu_is_disabled(cpu))
4342                                 continue;
4343                         pmc_select_cpu(cpu);
4344                         if (pmc_pcpu[cpu])
4345                                 (void) md->pmd_cleanup(cpu);
4346                 }
4347                 FREE(md, M_PMC);
4348                 md = NULL;
4349                 pmc_restore_cpu_binding(&pb);
4350         }
4351
4352         /* deallocate per-cpu structures */
4353         FREE(pmc_pcpu, M_PMC);
4354         pmc_pcpu = NULL;
4355
4356         FREE(pmc_pcpu_saved, M_PMC);
4357         pmc_pcpu_saved = NULL;
4358
4359         if (pmc_pmcdisp) {
4360                 FREE(pmc_pmcdisp, M_PMC);
4361                 pmc_pmcdisp = NULL;
4362         }
4363
4364         pmclog_shutdown();
4365
4366         sx_xunlock(&pmc_sx);    /* we are done */
4367 }
4368
4369 /*
4370  * The function called at load/unload.
4371  */
4372
4373 static int
4374 load (struct module *module __unused, int cmd, void *arg __unused)
4375 {
4376         int error;
4377
4378         error = 0;
4379
4380         switch (cmd) {
4381         case MOD_LOAD :
4382                 /* initialize the subsystem */
4383                 error = pmc_initialize();
4384                 if (error != 0)
4385                         break;
4386                 PMCDBG(MOD,INI,1, "syscall=%d ncpus=%d",
4387                     pmc_syscall_num, mp_ncpus);
4388                 break;
4389
4390
4391         case MOD_UNLOAD :
4392         case MOD_SHUTDOWN:
4393                 pmc_cleanup();
4394                 PMCDBG(MOD,INI,1, "%s", "unloaded");
4395                 break;
4396
4397         default :
4398                 error = EINVAL; /* XXX should panic(9) */
4399                 break;
4400         }
4401
4402         return error;
4403 }
4404
4405 /* memory pool */
4406 MALLOC_DEFINE(M_PMC, "pmc", "Memory space for the PMC module");