bsd/dev/dtrace/lockstat.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /* #pragma ident        "@(#)lockstat.c 1.12    08/01/16 SMI" */
  27
  28
  29 #ifdef KERNEL
  30 #ifndef _KERNEL
  31 #define _KERNEL /* Solaris vs. Darwin */
  32 #endif
  33 #endif
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/errno.h>
  38 #include <sys/stat.h>
  39 #include <sys/ioctl.h>
  40 #include <sys/conf.h>
  41 #include <sys/fcntl.h>
  42 #include <miscfs/devfs/devfs.h>
  43
  44 #include <sys/dtrace.h>
  45 #include <sys/dtrace_impl.h>
  46
  47 #include <sys/dtrace_glue.h>
  48
  49 #include <sys/lockstat.h>
  50
  51 #include <kern/processor.h>
  52
  53 #define membar_producer dtrace_membar_producer
  54
  55 #define PROBE_ARGS0(a, b, c, d, e) "\000"
  56 #define PROBE_ARGS1(a, b, c, d, e) a "\000"
  57 #define PROBE_ARGS2(a, b, c, d, e) a "\000" b "\000"
  58 #define PROBE_ARGS3(a, b, c, d, e) a "\000" b "\000" c "\000"
  59 #define PROBE_ARGS4(a, b, c, d, e) a "\000" b "\000" c "\000" d "\000"
  60 #define PROBE_ARGS5(a, b, c, d, e) a "\000" b "\000" c "\000" d "\000" e "\000"
  61 #define PROBE_ARGS_(a, b, c, d, e, n, ...) PROBE_ARGS##n(a, b, c, d, e)
  62 #define PROBE_ARGS(...) PROBE_ARGS_(__VA_ARGS__, 5, 4, 3, 2, 1, 0)
  63
  64 #define LOCKSTAT_PROBE(func, name, probe, ...) \
  65         {func, name, probe, DTRACE_IDNONE, PROBE_ARGS(__VA_ARGS__)}
  66
  67 /*
  68  * Hot patch values, x86
  69  */
  70 #if defined(__x86_64__)
  71 #define NOP     0x90
  72 #define RET     0xc3
  73 #define LOCKSTAT_AFRAMES 1
  74 #elif   defined(__arm__)
  75 #define NOP     0xE1A00000
  76 #define BXLR    0xE12FFF1E
  77 #define LOCKSTAT_AFRAMES 2
  78 #elif   defined(__arm64__)
  79 #define NOP     0xD503201F
  80 #define RET     0xD65f03c0
  81 #define LOCKSTAT_AFRAMES 2
  82 #else
  83 #error "not ported to this architecture"
  84 #endif
  85
  86 typedef struct lockstat_probe {
  87         const char      *lsp_func;
  88         const char      *lsp_name;
  89         int             lsp_probe;
  90         dtrace_id_t     lsp_id;
  91         const char      *lsp_args;
  92 } lockstat_probe_t;
  93
  94 lockstat_probe_t lockstat_probes[] =
  95 {
  96 #if defined(__x86_64__)
  97         /* Only provide implemented probes for each architecture  */
  98         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_ACQUIRE, LS_LCK_MTX_LOCK_ACQUIRE, "lck_mtx_t"),
  99         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_SPIN, LS_LCK_MTX_LOCK_SPIN, "lck_mtx_t", "uint64_t"),
 100         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_BLOCK, LS_LCK_MTX_LOCK_BLOCK, "lck_mtx_t", "uint64_t"),
 101         LOCKSTAT_PROBE(LS_LCK_MTX_TRY_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_LOCK_ACQUIRE, "lck_mtx_t"),
 102         LOCKSTAT_PROBE(LS_LCK_MTX_TRY_SPIN_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_SPIN_LOCK_ACQUIRE, "lck_mtx_t"),
 103         LOCKSTAT_PROBE(LS_LCK_MTX_UNLOCK, LSA_RELEASE, LS_LCK_MTX_UNLOCK_RELEASE, "lck_mtx_t"),
 104         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_ACQUIRE, LS_LCK_MTX_EXT_LOCK_ACQUIRE, "lck_mtx_t"),
 105         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_SPIN, LS_LCK_MTX_EXT_LOCK_SPIN, "lck_mtx_t", "uint64_t"),
 106         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_BLOCK, LS_LCK_MTX_EXT_LOCK_BLOCK, "lck_mtx_t", "uint64_t"),
 107 //      LOCKSTAT_PROBE(LS_LCK_MTX_EXT_TRY_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_EXT_LOCK_ACQUIRE)
 108         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_UNLOCK, LSA_RELEASE, LS_LCK_MTX_EXT_UNLOCK_RELEASE, "lck_mtx_t"),
 109         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK_SPIN_LOCK, LSA_ACQUIRE, LS_LCK_MTX_LOCK_SPIN_ACQUIRE, "lck_mtx_t"),
 110         // TODO: This should not be a uint64_t !
 111         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_ACQUIRE, LS_LCK_RW_LOCK_SHARED_ACQUIRE, "lck_rw_t", "uint64_t"),
 112         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_BLOCK, LS_LCK_RW_LOCK_SHARED_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 113         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_SPIN, LS_LCK_RW_LOCK_SHARED_SPIN, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 114         // TODO: This should NOT be a uint64_t
 115         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_ACQUIRE, LS_LCK_RW_LOCK_EXCL_ACQUIRE, "lck_rw_t", "uint64_t"),
 116         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_BLOCK, LS_LCK_RW_LOCK_EXCL_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 117         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_SPIN, LS_LCK_RW_LOCK_EXCL_SPIN, "lck_rw_t", "uint64_t", "int"),
 118         LOCKSTAT_PROBE(LS_LCK_RW_DONE, LSR_RELEASE, LS_LCK_RW_DONE_RELEASE, "lck_rw_t", "_Bool"),
 119         // TODO : This should NOT be a uint64_t
 120         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_SHARED, LSR_ACQUIRE, LS_LCK_RW_TRY_LOCK_SHARED_ACQUIRE, "lck_rw_t", "uint64_t"),
 121         // See above
 122         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_EXCL, LSR_ACQUIRE, LS_LCK_RW_TRY_LOCK_EXCL_ACQUIRE, "lck_rw_t", "uint64_t"),
 123         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_UPGRADE, LS_LCK_RW_LOCK_SHARED_TO_EXCL_UPGRADE, "lck_rw_t", "_Bool"),
 124         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_SPIN, LS_LCK_RW_LOCK_SHARED_TO_EXCL_SPIN, "lck_rw_t", "uint64_t"),
 125         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_BLOCK, LS_LCK_RW_LOCK_SHARED_TO_EXCL_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 126         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL_TO_SHARED, LSR_DOWNGRADE, LS_LCK_RW_LOCK_EXCL_TO_SHARED_DOWNGRADE, "lck_rw_t"),
 127         //TODO : Separate the probes for the hw_bit from the probe for the normal hw locks
 128         LOCKSTAT_PROBE(LS_LCK_SPIN_LOCK, LSS_ACQUIRE, LS_LCK_SPIN_LOCK_ACQUIRE, "hw_lock_t"),
 129         LOCKSTAT_PROBE(LS_LCK_SPIN_LOCK, LSS_SPIN, LS_LCK_SPIN_LOCK_SPIN, "hw_lock_t", "uint64_t", "uint64_t"),
 130         LOCKSTAT_PROBE(LS_LCK_SPIN_UNLOCK, LSS_RELEASE, LS_LCK_SPIN_UNLOCK_RELEASE, "hw_lock_t"),
 131 #elif defined(__arm__) || defined(__arm64__)
 132         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_ACQUIRE, LS_LCK_MTX_LOCK_ACQUIRE, "lck_mtx_t"),
 133 //      LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_SPIN, LS_LCK_MTX_LOCK_SPIN, "lck_mtx_t", "uint64_t"),
 134         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_BLOCK, LS_LCK_MTX_LOCK_BLOCK, "lck_mtx_t", "uint64_t"),
 135         LOCKSTAT_PROBE(LS_LCK_MTX_TRY_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_LOCK_ACQUIRE, "lck_mtx_t"),
 136 //      LOCKSTAT_PROBE(LS_LCK_MTX_TRY_SPIN_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_SPIN_LOCK_ACQUIRE, "lck_mtx_t"),
 137         LOCKSTAT_PROBE(LS_LCK_MTX_UNLOCK, LSA_RELEASE, LS_LCK_MTX_UNLOCK_RELEASE, "lck_mtx_t"),
 138         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_ACQUIRE, LS_LCK_MTX_EXT_LOCK_ACQUIRE, "lck_mtx_t"),
 139 //      LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_SPIN, LS_LCK_MTX_EXT_LOCK_SPIN, "lck_mtx_t", "uint64_t"),
 140         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_BLOCK, LS_LCK_MTX_EXT_LOCK_BLOCK, "lck_mtx_t", "uint64_t"),
 141 //      LOCKSTAT_PROBE(LS_LCK_MTX_EXT_TRY_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_EXT_LOCK_ACQUIRE)
 142 //      LOCKSTAT_PROBE(LS_LCK_MTX_EXT_UNLOCK, LSA_RELEASE, LS_LCK_MTX_EXT_UNLOCK_RELEASE, "lck_mtx_t"),
 143 //      LOCKSTAT_PROBE(LS_LCK_MTX_LOCK_SPIN_LOCK, LSA_ACQUIRE, LS_LCK_MTX_LOCK_SPIN_ACQUIRE, "lck_mtx_t"),
 144         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_ACQUIRE, LS_LCK_RW_LOCK_SHARED_ACQUIRE, "lck_rw_t", "uint64_t"),
 145         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_BLOCK, LS_LCK_RW_LOCK_SHARED_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 146         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_SPIN, LS_LCK_RW_LOCK_SHARED_SPIN, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 147         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_ACQUIRE, LS_LCK_RW_LOCK_EXCL_ACQUIRE, "lck_rw_t", "uint64_t"),
 148         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_BLOCK, LS_LCK_RW_LOCK_EXCL_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 149         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_SPIN, LS_LCK_RW_LOCK_EXCL_SPIN, "lck_rw_t", "uint64_t", "int"),
 150         LOCKSTAT_PROBE(LS_LCK_RW_DONE, LSR_RELEASE, LS_LCK_RW_DONE_RELEASE, "lck_rw_t", "_Bool"),
 151         // TODO : This should NOT be a uint64_t
 152         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_SHARED, LSR_ACQUIRE, LS_LCK_RW_TRY_LOCK_SHARED_ACQUIRE, "lck_rw_t", "uint64_t"),
 153         // See above
 154         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_EXCL, LSR_ACQUIRE, LS_LCK_RW_TRY_LOCK_EXCL_ACQUIRE, "lck_rw_t", "uint64_t"),
 155         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_UPGRADE, LS_LCK_RW_LOCK_SHARED_TO_EXCL_UPGRADE, "lck_rw_t", "_Bool"),
 156         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_SPIN, LS_LCK_RW_LOCK_SHARED_TO_EXCL_SPIN, "lck_rw_t", "uint64_t"),
 157         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_BLOCK, LS_LCK_RW_LOCK_SHARED_TO_EXCL_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 158         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL_TO_SHARED, LSR_DOWNGRADE, LS_LCK_RW_LOCK_EXCL_TO_SHARED_DOWNGRADE, "lck_rw_t"),
 159         //TODO : Separate the probes for the hw_bit from the probe for the normal hw locks
 160         LOCKSTAT_PROBE(LS_LCK_SPIN_LOCK, LSS_ACQUIRE, LS_LCK_SPIN_LOCK_ACQUIRE, "hw_lock_t"),
 161         LOCKSTAT_PROBE(LS_LCK_SPIN_LOCK, LSS_SPIN, LS_LCK_SPIN_LOCK_SPIN, "hw_lock_t", "uint64_t", "uint64_t"),
 162         LOCKSTAT_PROBE(LS_LCK_SPIN_UNLOCK, LSS_RELEASE, LS_LCK_SPIN_UNLOCK_RELEASE, "hw_lock_t"),
 163 #endif
 164         /* Interlock measurements would be nice, but later */
 165
 166 #ifdef  LATER
 167         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL_TO_SHARED, LSA_ILK_SPIN, LS_LCK_RW_LOCK_EXCL_TO_SHARED_ILK_SPIN),
 168         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_ILK_SPIN, LS_LCK_MTX_LOCK_ILK_SPIN),
 169         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_ILK_SPIN, LS_LCK_MTX_EXT_LOCK_ILK_SPIN),
 170         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_EXCL, LSA_ILK_SPIN, LS_LCK_RW_TRY_LOCK_EXCL_ILK_SPIN),
 171         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_SHARED, LSA_SPIN, LS_LCK_RW_TRY_LOCK_SHARED_SPIN)
 172 #endif
 173
 174         { NULL, NULL, 0, 0, NULL}
 175 };
 176
 177 dtrace_id_t lockstat_probemap[LS_NPROBES];
 178
 179 typedef struct lockstat_assembly_probe {
 180         int lsap_probe;
 181         vm_offset_t * lsap_patch_point;
 182 } lockstat_assembly_probe_t;
 183
 184
 185         lockstat_assembly_probe_t assembly_probes[] =
 186         {
 187                 { LS_LCK_INVALID, NULL }
 188         };
 189
 190
 191 /*
 192  * APPLE NOTE:
 193  * Hot patch is used to manipulate probe points by swapping between
 194  * no-op and return instructions.
 195  * The active flag indicates whether the probe point will turn on or off.
 196  *      on == plant a NOP and thus fall through to the probe call
 197  *     off == plant a RET and thus avoid the probe call completely
 198  * The ls_probe identifies which probe we will patch.
 199  */
 200 static
 201 void lockstat_hot_patch(boolean_t active, int ls_probe)
 202 {
 203 #pragma unused(active)
 204         int i;
 205
 206         /*
 207          * Loop through entire table, in case there are
 208          * multiple patch points per probe.
 209          */
 210         for (i = 0; assembly_probes[i].lsap_patch_point; i++) {
 211                 if (ls_probe == assembly_probes[i].lsap_probe)
 212 #if defined(__x86_64__)
 213                 {
 214                         uint8_t instr;
 215                         instr = (active ? NOP : RET );
 216                         (void) ml_nofault_copy( (vm_offset_t)&instr, *(assembly_probes[i].lsap_patch_point),
 217                                                                 sizeof(instr));
 218                 }
 219 #elif defined (__arm__)
 220                 {
 221                         uint32_t instr;
 222                         instr = (active ? NOP : BXLR );
 223                         (void) ml_nofault_copy( (vm_offset_t)&instr, *(assembly_probes[i].lsap_patch_point),
 224                                                                 sizeof(instr));
 225                 }
 226 #elif defined (__arm64__)
 227                 {
 228                         uint32_t instr;
 229                         instr = (active ? NOP : RET );
 230                         (void) ml_nofault_copy( (vm_offset_t)&instr, *(assembly_probes[i].lsap_patch_point),
 231                                                                 sizeof(instr));
 232                 }
 233 #endif
 234         } /* for */
 235 }
 236
 237 void (*lockstat_probe)(dtrace_id_t, uint64_t, uint64_t,
 238                                     uint64_t, uint64_t, uint64_t);
 239
 240
 241 /*
 242  * APPLE NOTE:
 243  * This wrapper is used only by assembler hot patched probes.
 244  */
 245 void
 246 lockstat_probe_wrapper(int probe, uintptr_t lp, int rwflag)
 247 {
 248         dtrace_id_t id;
 249         id = lockstat_probemap[probe];
 250         if (id != 0)
 251         {
 252                 (*lockstat_probe)(id, (uintptr_t)lp, (uint64_t)rwflag, 0,0,0);
 253         }
 254 }
 255
 256 static dtrace_provider_id_t lockstat_id;
 257
 258 /*ARGSUSED*/
 259 static int
 260 lockstat_enable(void *arg, dtrace_id_t id, void *parg)
 261 {
 262 #pragma unused(arg) /* __APPLE__ */
 263
 264         lockstat_probe_t *probe = parg;
 265
 266         ASSERT(!lockstat_probemap[probe->lsp_probe]);
 267
 268         lockstat_probemap[probe->lsp_probe] = id;
 269         membar_producer();
 270
 271         lockstat_hot_patch(TRUE, probe->lsp_probe);
 272         membar_producer();
 273         return(0);
 274
 275 }
 276
 277 /*ARGSUSED*/
 278 static void
 279 lockstat_disable(void *arg, dtrace_id_t id, void *parg)
 280 {
 281 #pragma unused(arg, id) /* __APPLE__ */
 282
 283         lockstat_probe_t *probe = parg;
 284         int i;
 285
 286         ASSERT(lockstat_probemap[probe->lsp_probe]);
 287
 288         lockstat_probemap[probe->lsp_probe] = 0;
 289         lockstat_hot_patch(FALSE, probe->lsp_probe);
 290         membar_producer();
 291
 292         /*
 293          * See if we have any probes left enabled.
 294          */
 295         for (i = 0; i < LS_NPROBES; i++) {
 296                 if (lockstat_probemap[i]) {
 297                         /*
 298                          * This probe is still enabled.  We don't need to deal
 299                          * with waiting for all threads to be out of the
 300                          * lockstat critical sections; just return.
 301                          */
 302                         return;
 303                 }
 304         }
 305
 306 }
 307
 308 /*ARGSUSED*/
 309 static void
 310 lockstat_provide(void *arg, const dtrace_probedesc_t *desc)
 311 {
 312 #pragma unused(arg, desc) /* __APPLE__ */
 313
 314         int i = 0;
 315
 316         for (i = 0; lockstat_probes[i].lsp_func != NULL; i++) {
 317                 lockstat_probe_t *probe = &lockstat_probes[i];
 318
 319                 if (dtrace_probe_lookup(lockstat_id, "mach_kernel",
 320                     probe->lsp_func, probe->lsp_name) != 0)
 321                         continue;
 322
 323                 ASSERT(!probe->lsp_id);
 324                 probe->lsp_id = dtrace_probe_create(lockstat_id,
 325                     "mach_kernel", probe->lsp_func, probe->lsp_name,
 326                     LOCKSTAT_AFRAMES, probe);
 327         }
 328 }
 329
 330
 331 /*ARGSUSED*/
 332 static void
 333 lockstat_destroy(void *arg, dtrace_id_t id, void *parg)
 334 {
 335 #pragma unused(arg, id) /* __APPLE__ */
 336
 337         lockstat_probe_t *probe = parg;
 338
 339         ASSERT(!lockstat_probemap[probe->lsp_probe]);
 340         probe->lsp_id = 0;
 341 }
 342
 343 static void
 344 lockstat_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
 345 {
 346 #pragma unused(arg, id)
 347         lockstat_probe_t *probe = parg;
 348         const char* argdesc = probe->lsp_args;
 349         int narg = 0;
 350
 351         desc->dtargd_native[0] = '\0';
 352         desc->dtargd_xlate[0] = '\0';
 353
 354         while(argdesc[0] != '\0') {
 355                 if (narg == desc->dtargd_ndx) {
 356                         strlcpy(desc->dtargd_native, argdesc, DTRACE_ARGTYPELEN);
 357                         return;
 358                 }
 359                 argdesc += strlen(argdesc) + 1;
 360                 narg++;
 361         }
 362
 363         desc->dtargd_ndx = DTRACE_ARGNONE;
 364 }
 365
 366 static dtrace_pattr_t lockstat_attr = {
 367 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 368 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
 369 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
 370 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 371 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 372 };
 373
 374 static dtrace_pops_t lockstat_pops = {
 375         .dtps_provide =         lockstat_provide,
 376         .dtps_provide_module =  NULL,
 377         .dtps_enable =          lockstat_enable,
 378         .dtps_disable =         lockstat_disable,
 379         .dtps_suspend =         NULL,
 380         .dtps_resume =          NULL,
 381         .dtps_getargdesc =      lockstat_getargdesc,
 382         .dtps_getargval =       NULL,
 383         .dtps_usermode =        NULL,
 384         .dtps_destroy =         lockstat_destroy
 385 };
 386
 387 static int
 388 lockstat_attach(dev_info_t *devi)
 389 {
 390         if (ddi_create_minor_node(devi, "lockstat", S_IFCHR, 0,
 391             DDI_PSEUDO, 0) == DDI_FAILURE ||
 392             dtrace_register("lockstat", &lockstat_attr, DTRACE_PRIV_KERNEL,
 393             NULL, &lockstat_pops, NULL, &lockstat_id) != 0) {
 394                 ddi_remove_minor_node(devi, NULL);
 395                 return (DDI_FAILURE);
 396         }
 397
 398         lockstat_probe = dtrace_probe;
 399         membar_producer();
 400
 401         return (DDI_SUCCESS);
 402 }
 403
 404 d_open_t _lockstat_open;
 405
 406 int _lockstat_open(dev_t dev, int flags, int devtype, struct proc *p)
 407 {
 408 #pragma unused(dev,flags,devtype,p)
 409         return 0;
 410 }
 411
 412 #define LOCKSTAT_MAJOR  -24 /* let the kernel pick the device number */
 413
 414 /*
 415  * A struct describing which functions will get invoked for certain
 416  * actions.
 417  */
 418 static struct cdevsw lockstat_cdevsw =
 419 {
 420         _lockstat_open,         /* open */
 421         eno_opcl,                       /* close */
 422         eno_rdwrt,                      /* read */
 423         eno_rdwrt,                      /* write */
 424         eno_ioctl,                      /* ioctl */
 425         (stop_fcn_t *)nulldev, /* stop */
 426         (reset_fcn_t *)nulldev, /* reset */
 427         NULL,                           /* tty's */
 428         eno_select,                     /* select */
 429         eno_mmap,                       /* mmap */
 430         eno_strat,                      /* strategy */
 431         eno_getc,                       /* getc */
 432         eno_putc,                       /* putc */
 433         0                                       /* type */
 434 };
 435
 436 void lockstat_init( void );
 437
 438 void lockstat_init( void )
 439 {
 440         int majdevno = cdevsw_add(LOCKSTAT_MAJOR, &lockstat_cdevsw);
 441
 442         if (majdevno < 0) {
 443                 printf("lockstat_init: failed to allocate a major number!\n");
 444                 return;
 445         }
 446
 447         lockstat_attach((dev_info_t*)(uintptr_t)majdevno);
 448 }
 449 #undef LOCKSTAT_MAJOR