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/lock_stat.h>
  52
  53 #include <kern/processor.h>
  54
  55 #define membar_producer dtrace_membar_producer
  56
  57 #define PROBE_ARGS0(a, b, c, d, e) "\000"
  58 #define PROBE_ARGS1(a, b, c, d, e) a "\000"
  59 #define PROBE_ARGS2(a, b, c, d, e) a "\000" b "\000"
  60 #define PROBE_ARGS3(a, b, c, d, e) a "\000" b "\000" c "\000"
  61 #define PROBE_ARGS4(a, b, c, d, e) a "\000" b "\000" c "\000" d "\000"
  62 #define PROBE_ARGS5(a, b, c, d, e) a "\000" b "\000" c "\000" d "\000" e "\000"
  63 #define PROBE_ARGS_(a, b, c, d, e, n, ...) PROBE_ARGS##n(a, b, c, d, e)
  64 #define PROBE_ARGS(...) PROBE_ARGS_(__VA_ARGS__, 5, 4, 3, 2, 1, 0)
  65
  66 #define LOCKSTAT_PROBE(func, name, probe, ...) \
  67         {func, name, probe, DTRACE_IDNONE, PROBE_ARGS(__VA_ARGS__)}
  68
  69 /*
  70  * Hot patch values, x86
  71  */
  72 #if defined(__x86_64__)
  73 #define NOP     0x90
  74 #define RET     0xc3
  75 #define LOCKSTAT_AFRAMES 1
  76 #elif   defined(__arm__)
  77 #define NOP     0xE1A00000
  78 #define BXLR    0xE12FFF1E
  79 #define LOCKSTAT_AFRAMES 2
  80 #elif   defined(__arm64__)
  81 #define NOP     0xD503201F
  82 #define RET     0xD65f03c0
  83 #define LOCKSTAT_AFRAMES 2
  84 #else
  85 #error "not ported to this architecture"
  86 #endif
  87
  88 typedef struct lockstat_probe {
  89         const char      *lsp_func;
  90         const char      *lsp_name;
  91         int             lsp_probe;
  92         dtrace_id_t     lsp_id;
  93         const char      *lsp_args;
  94 } lockstat_probe_t;
  95
  96 lockstat_probe_t lockstat_probes[] =
  97 {
  98 #if defined(__x86_64__)
  99         /* Only provide implemented probes for each architecture  */
 100         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_ACQUIRE, LS_LCK_MTX_LOCK_ACQUIRE, "lck_mtx_t"),
 101         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_SPIN, LS_LCK_MTX_LOCK_SPIN, "lck_mtx_t", "uint64_t"),
 102         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_BLOCK, LS_LCK_MTX_LOCK_BLOCK, "lck_mtx_t", "uint64_t"),
 103         LOCKSTAT_PROBE(LS_LCK_MTX_TRY_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_LOCK_ACQUIRE, "lck_mtx_t"),
 104         LOCKSTAT_PROBE(LS_LCK_MTX_TRY_SPIN_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_SPIN_LOCK_ACQUIRE, "lck_mtx_t"),
 105         LOCKSTAT_PROBE(LS_LCK_MTX_UNLOCK, LSA_RELEASE, LS_LCK_MTX_UNLOCK_RELEASE, "lck_mtx_t"),
 106         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_ACQUIRE, LS_LCK_MTX_EXT_LOCK_ACQUIRE, "lck_mtx_t"),
 107         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_SPIN, LS_LCK_MTX_EXT_LOCK_SPIN, "lck_mtx_t", "uint64_t"),
 108         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_BLOCK, LS_LCK_MTX_EXT_LOCK_BLOCK, "lck_mtx_t", "uint64_t"),
 109 //      LOCKSTAT_PROBE(LS_LCK_MTX_EXT_TRY_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_EXT_LOCK_ACQUIRE)
 110         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_UNLOCK, LSA_RELEASE, LS_LCK_MTX_EXT_UNLOCK_RELEASE, "lck_mtx_t"),
 111         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK_SPIN_LOCK, LSA_ACQUIRE, LS_LCK_MTX_LOCK_SPIN_ACQUIRE, "lck_mtx_t"),
 112         // TODO: This should not be a uint64_t !
 113         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_ACQUIRE, LS_LCK_RW_LOCK_SHARED_ACQUIRE, "lck_rw_t", "uint64_t"),
 114         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_BLOCK, LS_LCK_RW_LOCK_SHARED_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 115         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_SPIN, LS_LCK_RW_LOCK_SHARED_SPIN, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 116         // TODO: This should NOT be a uint64_t
 117         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_ACQUIRE, LS_LCK_RW_LOCK_EXCL_ACQUIRE, "lck_rw_t", "uint64_t"),
 118         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_BLOCK, LS_LCK_RW_LOCK_EXCL_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 119         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_SPIN, LS_LCK_RW_LOCK_EXCL_SPIN, "lck_rw_t", "uint64_t", "int"),
 120         LOCKSTAT_PROBE(LS_LCK_RW_DONE, LSR_RELEASE, LS_LCK_RW_DONE_RELEASE, "lck_rw_t", "_Bool"),
 121         // TODO : This should NOT be a uint64_t
 122         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_SHARED, LSR_ACQUIRE, LS_LCK_RW_TRY_LOCK_SHARED_ACQUIRE, "lck_rw_t", "uint64_t"),
 123         // See above
 124         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_EXCL, LSR_ACQUIRE, LS_LCK_RW_TRY_LOCK_EXCL_ACQUIRE, "lck_rw_t", "uint64_t"),
 125         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_UPGRADE, LS_LCK_RW_LOCK_SHARED_TO_EXCL_UPGRADE, "lck_rw_t", "_Bool"),
 126         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_SPIN, LS_LCK_RW_LOCK_SHARED_TO_EXCL_SPIN, "lck_rw_t", "uint64_t"),
 127         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"),
 128         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL_TO_SHARED, LSR_DOWNGRADE, LS_LCK_RW_LOCK_EXCL_TO_SHARED_DOWNGRADE, "lck_rw_t"),
 129         //TODO : Separate the probes for the hw_bit from the probe for the normal hw locks
 130         LOCKSTAT_PROBE(LS_LCK_SPIN_LOCK, LSS_ACQUIRE, LS_LCK_SPIN_LOCK_ACQUIRE, "hw_lock_t"),
 131         LOCKSTAT_PROBE(LS_LCK_SPIN_LOCK, LSS_SPIN, LS_LCK_SPIN_LOCK_SPIN, "hw_lock_t", "uint64_t", "uint64_t"),
 132         LOCKSTAT_PROBE(LS_LCK_SPIN_UNLOCK, LSS_RELEASE, LS_LCK_SPIN_UNLOCK_RELEASE, "hw_lock_t"),
 133 #elif defined(__arm__) || defined(__arm64__)
 134         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_ACQUIRE, LS_LCK_MTX_LOCK_ACQUIRE, "lck_mtx_t"),
 135 //      LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_SPIN, LS_LCK_MTX_LOCK_SPIN, "lck_mtx_t", "uint64_t"),
 136         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_BLOCK, LS_LCK_MTX_LOCK_BLOCK, "lck_mtx_t", "uint64_t"),
 137         LOCKSTAT_PROBE(LS_LCK_MTX_TRY_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_LOCK_ACQUIRE, "lck_mtx_t"),
 138 //      LOCKSTAT_PROBE(LS_LCK_MTX_TRY_SPIN_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_SPIN_LOCK_ACQUIRE, "lck_mtx_t"),
 139         LOCKSTAT_PROBE(LS_LCK_MTX_UNLOCK, LSA_RELEASE, LS_LCK_MTX_UNLOCK_RELEASE, "lck_mtx_t"),
 140         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_ACQUIRE, LS_LCK_MTX_EXT_LOCK_ACQUIRE, "lck_mtx_t"),
 141 //      LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_SPIN, LS_LCK_MTX_EXT_LOCK_SPIN, "lck_mtx_t", "uint64_t"),
 142         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_BLOCK, LS_LCK_MTX_EXT_LOCK_BLOCK, "lck_mtx_t", "uint64_t"),
 143 //      LOCKSTAT_PROBE(LS_LCK_MTX_EXT_TRY_LOCK, LSA_ACQUIRE, LS_LCK_MTX_TRY_EXT_LOCK_ACQUIRE)
 144 //      LOCKSTAT_PROBE(LS_LCK_MTX_EXT_UNLOCK, LSA_RELEASE, LS_LCK_MTX_EXT_UNLOCK_RELEASE, "lck_mtx_t"),
 145 //      LOCKSTAT_PROBE(LS_LCK_MTX_LOCK_SPIN_LOCK, LSA_ACQUIRE, LS_LCK_MTX_LOCK_SPIN_ACQUIRE, "lck_mtx_t"),
 146         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_ACQUIRE, LS_LCK_RW_LOCK_SHARED_ACQUIRE, "lck_rw_t", "uint64_t"),
 147         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_BLOCK, LS_LCK_RW_LOCK_SHARED_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 148         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED, LSR_SPIN, LS_LCK_RW_LOCK_SHARED_SPIN, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 149         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_ACQUIRE, LS_LCK_RW_LOCK_EXCL_ACQUIRE, "lck_rw_t", "uint64_t"),
 150         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_BLOCK, LS_LCK_RW_LOCK_EXCL_BLOCK, "lck_rw_t", "uint64_t", "_Bool", "_Bool", "int"),
 151         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL, LSR_SPIN, LS_LCK_RW_LOCK_EXCL_SPIN, "lck_rw_t", "uint64_t", "int"),
 152         LOCKSTAT_PROBE(LS_LCK_RW_DONE, LSR_RELEASE, LS_LCK_RW_DONE_RELEASE, "lck_rw_t", "_Bool"),
 153         // TODO : This should NOT be a uint64_t
 154         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_SHARED, LSR_ACQUIRE, LS_LCK_RW_TRY_LOCK_SHARED_ACQUIRE, "lck_rw_t", "uint64_t"),
 155         // See above
 156         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_EXCL, LSR_ACQUIRE, LS_LCK_RW_TRY_LOCK_EXCL_ACQUIRE, "lck_rw_t", "uint64_t"),
 157         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_UPGRADE, LS_LCK_RW_LOCK_SHARED_TO_EXCL_UPGRADE, "lck_rw_t", "_Bool"),
 158         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_SHARED_TO_EXCL, LSR_SPIN, LS_LCK_RW_LOCK_SHARED_TO_EXCL_SPIN, "lck_rw_t", "uint64_t"),
 159         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"),
 160         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL_TO_SHARED, LSR_DOWNGRADE, LS_LCK_RW_LOCK_EXCL_TO_SHARED_DOWNGRADE, "lck_rw_t"),
 161         //TODO : Separate the probes for the hw_bit from the probe for the normal hw locks
 162         LOCKSTAT_PROBE(LS_LCK_SPIN_LOCK, LSS_ACQUIRE, LS_LCK_SPIN_LOCK_ACQUIRE, "hw_lock_t"),
 163         LOCKSTAT_PROBE(LS_LCK_SPIN_LOCK, LSS_SPIN, LS_LCK_SPIN_LOCK_SPIN, "hw_lock_t", "uint64_t", "uint64_t"),
 164         LOCKSTAT_PROBE(LS_LCK_SPIN_UNLOCK, LSS_RELEASE, LS_LCK_SPIN_UNLOCK_RELEASE, "hw_lock_t"),
 165 #endif
 166         /* Interlock measurements would be nice, but later */
 167
 168 #ifdef  LATER
 169         LOCKSTAT_PROBE(LS_LCK_RW_LOCK_EXCL_TO_SHARED, LSA_ILK_SPIN, LS_LCK_RW_LOCK_EXCL_TO_SHARED_ILK_SPIN),
 170         LOCKSTAT_PROBE(LS_LCK_MTX_LOCK, LSA_ILK_SPIN, LS_LCK_MTX_LOCK_ILK_SPIN),
 171         LOCKSTAT_PROBE(LS_LCK_MTX_EXT_LOCK, LSA_ILK_SPIN, LS_LCK_MTX_EXT_LOCK_ILK_SPIN),
 172         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_EXCL, LSA_ILK_SPIN, LS_LCK_RW_TRY_LOCK_EXCL_ILK_SPIN),
 173         LOCKSTAT_PROBE(LS_LCK_RW_TRY_LOCK_SHARED, LSA_SPIN, LS_LCK_RW_TRY_LOCK_SHARED_SPIN)
 174 #endif
 175
 176         {
 177                 NULL, NULL, 0, 0, NULL
 178         }
 179 };
 180
 181 dtrace_id_t lockstat_probemap[LS_NPROBES];
 182 void (*lockstat_probe)(dtrace_id_t, uint64_t, uint64_t,
 183     uint64_t, uint64_t, uint64_t);
 184
 185 static dtrace_provider_id_t lockstat_id;
 186
 187 /*ARGSUSED*/
 188 static int
 189 lockstat_enable(void *arg, dtrace_id_t id, void *parg)
 190 {
 191 #pragma unused(arg) /* __APPLE__ */
 192
 193         lockstat_probe_t *probe = parg;
 194
 195         ASSERT(!lockstat_probemap[probe->lsp_probe]);
 196
 197         lockstat_probemap[probe->lsp_probe] = id;
 198         membar_producer();
 199
 200         membar_producer();
 201         return 0;
 202 }
 203
 204 /*ARGSUSED*/
 205 static void
 206 lockstat_disable(void *arg, dtrace_id_t id, void *parg)
 207 {
 208 #pragma unused(arg, id) /* __APPLE__ */
 209
 210         lockstat_probe_t *probe = parg;
 211         int i;
 212
 213         ASSERT(lockstat_probemap[probe->lsp_probe]);
 214
 215         lockstat_probemap[probe->lsp_probe] = 0;
 216         membar_producer();
 217
 218         /*
 219          * See if we have any probes left enabled.
 220          */
 221         for (i = 0; i < LS_NPROBES; i++) {
 222                 if (lockstat_probemap[i]) {
 223                         /*
 224                          * This probe is still enabled.  We don't need to deal
 225                          * with waiting for all threads to be out of the
 226                          * lockstat critical sections; just return.
 227                          */
 228                         return;
 229                 }
 230         }
 231 }
 232
 233 /*ARGSUSED*/
 234 static void
 235 lockstat_provide(void *arg, const dtrace_probedesc_t *desc)
 236 {
 237 #pragma unused(arg, desc) /* __APPLE__ */
 238
 239         int i = 0;
 240
 241         for (i = 0; lockstat_probes[i].lsp_func != NULL; i++) {
 242                 lockstat_probe_t *probe = &lockstat_probes[i];
 243
 244                 if (dtrace_probe_lookup(lockstat_id, "mach_kernel",
 245                     probe->lsp_func, probe->lsp_name) != 0) {
 246                         continue;
 247                 }
 248
 249                 ASSERT(!probe->lsp_id);
 250                 probe->lsp_id = dtrace_probe_create(lockstat_id,
 251                     "mach_kernel", probe->lsp_func, probe->lsp_name,
 252                     LOCKSTAT_AFRAMES, probe);
 253         }
 254 }
 255
 256
 257 /*ARGSUSED*/
 258 static void
 259 lockstat_destroy(void *arg, dtrace_id_t id, void *parg)
 260 {
 261 #pragma unused(arg, id) /* __APPLE__ */
 262
 263         lockstat_probe_t *probe = parg;
 264
 265         ASSERT(!lockstat_probemap[probe->lsp_probe]);
 266         probe->lsp_id = 0;
 267 }
 268
 269 static void
 270 lockstat_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
 271 {
 272 #pragma unused(arg, id)
 273         lockstat_probe_t *probe = parg;
 274         const char* argdesc = probe->lsp_args;
 275         int narg = 0;
 276
 277         desc->dtargd_native[0] = '\0';
 278         desc->dtargd_xlate[0] = '\0';
 279
 280         while (argdesc[0] != '\0') {
 281                 if (narg == desc->dtargd_ndx) {
 282                         strlcpy(desc->dtargd_native, argdesc, DTRACE_ARGTYPELEN);
 283                         return;
 284                 }
 285                 argdesc += strlen(argdesc) + 1;
 286                 narg++;
 287         }
 288
 289         desc->dtargd_ndx = DTRACE_ARGNONE;
 290 }
 291
 292 static dtrace_pattr_t lockstat_attr = {
 293         { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 294         { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
 295         { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
 296         { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 297         { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 298 };
 299
 300 static dtrace_pops_t lockstat_pops = {
 301         .dtps_provide =         lockstat_provide,
 302         .dtps_provide_module =  NULL,
 303         .dtps_enable =          lockstat_enable,
 304         .dtps_disable =         lockstat_disable,
 305         .dtps_suspend =         NULL,
 306         .dtps_resume =          NULL,
 307         .dtps_getargdesc =      lockstat_getargdesc,
 308         .dtps_getargval =       NULL,
 309         .dtps_usermode =        NULL,
 310         .dtps_destroy =         lockstat_destroy
 311 };
 312
 313 static int
 314 lockstat_attach(dev_info_t *devi)
 315 {
 316         if (ddi_create_minor_node(devi, "lockstat", S_IFCHR, 0,
 317             DDI_PSEUDO, 0) == DDI_FAILURE ||
 318             dtrace_register("lockstat", &lockstat_attr, DTRACE_PRIV_KERNEL,
 319             NULL, &lockstat_pops, NULL, &lockstat_id) != 0) {
 320                 ddi_remove_minor_node(devi, NULL);
 321                 return DDI_FAILURE;
 322         }
 323
 324         lockstat_probe = dtrace_probe;
 325         membar_producer();
 326
 327         return DDI_SUCCESS;
 328 }
 329
 330 d_open_t _lockstat_open;
 331
 332 int
 333 _lockstat_open(dev_t dev, int flags, int devtype, struct proc *p)
 334 {
 335 #pragma unused(dev,flags,devtype,p)
 336         return 0;
 337 }
 338
 339 #define LOCKSTAT_MAJOR  -24 /* let the kernel pick the device number */
 340
 341 /*
 342  * A struct describing which functions will get invoked for certain
 343  * actions.
 344  */
 345 static struct cdevsw lockstat_cdevsw =
 346 {
 347         _lockstat_open,         /* open */
 348         eno_opcl,                       /* close */
 349         eno_rdwrt,                      /* read */
 350         eno_rdwrt,                      /* write */
 351         eno_ioctl,                      /* ioctl */
 352         (stop_fcn_t *)nulldev, /* stop */
 353         (reset_fcn_t *)nulldev, /* reset */
 354         NULL,                           /* tty's */
 355         eno_select,                     /* select */
 356         eno_mmap,                       /* mmap */
 357         eno_strat,                      /* strategy */
 358         eno_getc,                       /* getc */
 359         eno_putc,                       /* putc */
 360         0                                       /* type */
 361 };
 362
 363 void lockstat_init( void );
 364
 365 void
 366 lockstat_init( void )
 367 {
 368         int majdevno = cdevsw_add(LOCKSTAT_MAJOR, &lockstat_cdevsw);
 369
 370         if (majdevno < 0) {
 371                 printf("lockstat_init: failed to allocate a major number!\n");
 372                 return;
 373         }
 374
 375         lockstat_attach((dev_info_t*)(uintptr_t)majdevno);
 376 }
 377 #undef LOCKSTAT_MAJOR