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 2008 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 #include <sys/modctl.h> 29 #include <sys/sunddi.h> 30 #include <sys/dtrace.h> 31 #include <sys/kobj.h> 32 #include <sys/stat.h> 33 #include <sys/conf.h> 34 #include <vm/seg_kmem.h> 35 #include <sys/stack.h> 36 #include <sys/frame.h> 37 #include <sys/dtrace_impl.h> 38 #include <sys/cmn_err.h> 39 #include <sys/sysmacros.h> 40 #include <sys/privregs.h> 41 #include <sys/sdt_impl.h> 42 43 #define SDT_PATCHVAL 0xf0 44 #define SDT_ADDR2NDX(addr) ((((uintptr_t)(addr)) >> 4) & sdt_probetab_mask) 45 #define SDT_PROBETAB_SIZE 0x1000 /* 4k entries -- 16K total */ 46 47 static dev_info_t *sdt_devi; 48 static int sdt_verbose = 0; 49 static sdt_probe_t **sdt_probetab; 50 static int sdt_probetab_size; 51 static int sdt_probetab_mask; 52 53 /*ARGSUSED*/ 54 static int 55 sdt_invop(uintptr_t addr, uintptr_t *stack, uintptr_t eax) 56 { 57 uintptr_t stack0, stack1, stack2, stack3, stack4; 58 int i = 0; 59 sdt_probe_t *sdt = sdt_probetab[SDT_ADDR2NDX(addr)]; 60 61 #ifdef __amd64 62 /* 63 * On amd64, stack[0] contains the dereferenced stack pointer, 64 * stack[1] contains savfp, stack[2] contains savpc. We want 65 * to step over these entries. 66 */ 67 i += 3; 68 #endif 69 70 for (; sdt != NULL; sdt = sdt->sdp_hashnext) { 71 if ((uintptr_t)sdt->sdp_patchpoint == addr) { 72 /* 73 * When accessing the arguments on the stack, we must 74 * protect against accessing beyond the stack. We can 75 * safely set NOFAULT here -- we know that interrupts 76 * are already disabled. 77 */ 78 DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); 79 stack0 = stack[i++]; 80 stack1 = stack[i++]; 81 stack2 = stack[i++]; 82 stack3 = stack[i++]; 83 stack4 = stack[i++]; 84 DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT | 85 CPU_DTRACE_BADADDR); 86 87 dtrace_probe(sdt->sdp_id, stack0, stack1, 88 stack2, stack3, stack4); 89 90 return (DTRACE_INVOP_NOP); 91 } 92 } 93 94 return (0); 95 } 96 97 /*ARGSUSED*/ 98 static void 99 sdt_provide_module(void *arg, struct modctl *ctl) 100 { 101 struct module *mp = ctl->mod_mp; 102 char *modname = ctl->mod_modname; 103 sdt_probedesc_t *sdpd; 104 sdt_probe_t *sdp, *old; 105 sdt_provider_t *prov; 106 int len; 107 108 /* 109 * One for all, and all for one: if we haven't yet registered all of 110 * our providers, we'll refuse to provide anything. 111 */ 112 for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) { 113 if (prov->sdtp_id == DTRACE_PROVNONE) 114 return; 115 } 116 117 if (mp->sdt_nprobes != 0 || (sdpd = mp->sdt_probes) == NULL) 118 return; 119 120 for (sdpd = mp->sdt_probes; sdpd != NULL; sdpd = sdpd->sdpd_next) { 121 char *name = sdpd->sdpd_name, *func, *nname; 122 int i, j; 123 sdt_provider_t *prov; 124 ulong_t offs; 125 dtrace_id_t id; 126 127 for (prov = sdt_providers; prov->sdtp_prefix != NULL; prov++) { 128 char *prefix = prov->sdtp_prefix; 129 130 if (strncmp(name, prefix, strlen(prefix)) == 0) { 131 name += strlen(prefix); 132 break; 133 } 134 } 135 136 nname = kmem_alloc(len = strlen(name) + 1, KM_SLEEP); 137 138 for (i = 0, j = 0; name[j] != '\0'; i++) { 139 if (name[j] == '_' && name[j + 1] == '_') { 140 nname[i] = '-'; 141 j += 2; 142 } else { 143 nname[i] = name[j++]; 144 } 145 } 146 147 nname[i] = '\0'; 148 149 sdp = kmem_zalloc(sizeof (sdt_probe_t), KM_SLEEP); 150 sdp->sdp_loadcnt = ctl->mod_loadcnt; 151 sdp->sdp_ctl = ctl; 152 sdp->sdp_name = nname; 153 sdp->sdp_namelen = len; 154 sdp->sdp_provider = prov; 155 156 func = kobj_searchsym(mp, sdpd->sdpd_offset, &offs); 157 158 if (func == NULL) 159 func = "<unknown>"; 160 161 /* 162 * We have our provider. Now create the probe. 163 */ 164 if ((id = dtrace_probe_lookup(prov->sdtp_id, modname, 165 func, nname)) != DTRACE_IDNONE) { 166 old = dtrace_probe_arg(prov->sdtp_id, id); 167 ASSERT(old != NULL); 168 169 sdp->sdp_next = old->sdp_next; 170 sdp->sdp_id = id; 171 old->sdp_next = sdp; 172 } else { 173 sdp->sdp_id = dtrace_probe_create(prov->sdtp_id, 174 modname, func, nname, 3, sdp); 175 176 mp->sdt_nprobes++; 177 } 178 179 sdp->sdp_hashnext = 180 sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)]; 181 sdt_probetab[SDT_ADDR2NDX(sdpd->sdpd_offset)] = sdp; 182 183 sdp->sdp_patchval = SDT_PATCHVAL; 184 sdp->sdp_patchpoint = (uint8_t *)sdpd->sdpd_offset; 185 sdp->sdp_savedval = *sdp->sdp_patchpoint; 186 } 187 } 188 189 /*ARGSUSED*/ 190 static void 191 sdt_destroy(void *arg, dtrace_id_t id, void *parg) 192 { 193 sdt_probe_t *sdp = parg, *old, *last, *hash; 194 struct modctl *ctl = sdp->sdp_ctl; 195 int ndx; 196 197 if (ctl != NULL && ctl->mod_loadcnt == sdp->sdp_loadcnt) { 198 if ((ctl->mod_loadcnt == sdp->sdp_loadcnt && 199 ctl->mod_loaded)) { 200 ((struct module *)(ctl->mod_mp))->sdt_nprobes--; 201 } 202 } 203 204 while (sdp != NULL) { 205 old = sdp; 206 207 /* 208 * Now we need to remove this probe from the sdt_probetab. 209 */ 210 ndx = SDT_ADDR2NDX(sdp->sdp_patchpoint); 211 last = NULL; 212 hash = sdt_probetab[ndx]; 213 214 while (hash != sdp) { 215 ASSERT(hash != NULL); 216 last = hash; 217 hash = hash->sdp_hashnext; 218 } 219 220 if (last != NULL) { 221 last->sdp_hashnext = sdp->sdp_hashnext; 222 } else { 223 sdt_probetab[ndx] = sdp->sdp_hashnext; 224 } 225 226 kmem_free(sdp->sdp_name, sdp->sdp_namelen); 227 sdp = sdp->sdp_next; 228 kmem_free(old, sizeof (sdt_probe_t)); 229 } 230 } 231 232 /*ARGSUSED*/ 233 static void 234 sdt_enable(void *arg, dtrace_id_t id, void *parg) 235 { 236 sdt_probe_t *sdp = parg; 237 struct modctl *ctl = sdp->sdp_ctl; 238 239 ctl->mod_nenabled++; 240 241 /* 242 * If this module has disappeared since we discovered its probes, 243 * refuse to enable it. 244 */ 245 if (!ctl->mod_loaded) { 246 if (sdt_verbose) { 247 cmn_err(CE_NOTE, "sdt is failing for probe %s " 248 "(module %s unloaded)", 249 sdp->sdp_name, ctl->mod_modname); 250 } 251 goto err; 252 } 253 254 /* 255 * Now check that our modctl has the expected load count. If it 256 * doesn't, this module must have been unloaded and reloaded -- and 257 * we're not going to touch it. 258 */ 259 if (ctl->mod_loadcnt != sdp->sdp_loadcnt) { 260 if (sdt_verbose) { 261 cmn_err(CE_NOTE, "sdt is failing for probe %s " 262 "(module %s reloaded)", 263 sdp->sdp_name, ctl->mod_modname); 264 } 265 goto err; 266 } 267 268 while (sdp != NULL) { 269 *sdp->sdp_patchpoint = sdp->sdp_patchval; 270 sdp = sdp->sdp_next; 271 } 272 err: 273 ; 274 } 275 276 /*ARGSUSED*/ 277 static void 278 sdt_disable(void *arg, dtrace_id_t id, void *parg) 279 { 280 sdt_probe_t *sdp = parg; 281 struct modctl *ctl = sdp->sdp_ctl; 282 283 ctl->mod_nenabled--; 284 285 if (!ctl->mod_loaded || ctl->mod_loadcnt != sdp->sdp_loadcnt) 286 goto err; 287 288 while (sdp != NULL) { 289 *sdp->sdp_patchpoint = sdp->sdp_savedval; 290 sdp = sdp->sdp_next; 291 } 292 293 err: 294 ; 295 } 296 297 /*ARGSUSED*/ 298 uint64_t 299 sdt_getarg(void *arg, dtrace_id_t id, void *parg, int argno, int aframes) 300 { 301 uintptr_t val; 302 struct frame *fp = (struct frame *)dtrace_getfp(); 303 uintptr_t *stack; 304 int i; 305 #if defined(__amd64) 306 /* 307 * A total of 6 arguments are passed via registers; any argument with 308 * index of 5 or lower is therefore in a register. 309 */ 310 int inreg = 5; 311 #endif 312 313 for (i = 1; i <= aframes; i++) { 314 fp = (struct frame *)(fp->fr_savfp); 315 316 if (fp->fr_savpc == (pc_t)dtrace_invop_callsite) { 317 #if !defined(__amd64) 318 /* 319 * If we pass through the invalid op handler, we will 320 * use the pointer that it passed to the stack as the 321 * second argument to dtrace_invop() as the pointer to 322 * the stack. When using this stack, we must step 323 * beyond the EIP/RIP that was pushed when the trap was 324 * taken -- hence the "+ 1" below. 325 */ 326 stack = ((uintptr_t **)&fp[1])[1]; 327 #else 328 /* 329 * In the case of amd64, we will use the pointer to the 330 * regs structure that was pushed when we took the 331 * trap. To get this structure, we must increment 332 * beyond the frame structure, and then again beyond 333 * the calling RIP stored in dtrace_invop(). If the 334 * argument that we're seeking is passed on the stack, 335 * we'll pull the true stack pointer out of the saved 336 * registers and decrement our argument by the number 337 * of arguments passed in registers; if the argument 338 * we're seeking is passed in regsiters, we can just 339 * load it directly. 340 */ 341 struct regs *rp = (struct regs *)((uintptr_t)&fp[1] + 342 sizeof (uintptr_t)); 343 344 if (argno <= inreg) { 345 stack = (uintptr_t *)&rp->r_rdi; 346 } else { 347 stack = (uintptr_t *)(rp->r_rsp); 348 argno -= inreg; 349 } 350 #endif 351 goto load; 352 } 353 } 354 355 load: 356 DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT); 357 val = stack[argno]; 358 DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT); 359 360 return (val); 361 } 362 363 static dtrace_pops_t sdt_pops = { 364 NULL, 365 sdt_provide_module, 366 sdt_enable, 367 sdt_disable, 368 NULL, 369 NULL, 370 sdt_getargdesc, 371 sdt_getarg, 372 NULL, 373 sdt_destroy 374 }; 375 376 /*ARGSUSED*/ 377 static int 378 sdt_attach(dev_info_t *devi, ddi_attach_cmd_t cmd) 379 { 380 sdt_provider_t *prov; 381 382 if (ddi_create_minor_node(devi, "sdt", S_IFCHR, 383 0, DDI_PSEUDO, NULL) == DDI_FAILURE) { 384 cmn_err(CE_NOTE, "/dev/sdt couldn't create minor node"); 385 ddi_remove_minor_node(devi, NULL); 386 return (DDI_FAILURE); 387 } 388 389 ddi_report_dev(devi); 390 sdt_devi = devi; 391 392 if (sdt_probetab_size == 0) 393 sdt_probetab_size = SDT_PROBETAB_SIZE; 394 395 sdt_probetab_mask = sdt_probetab_size - 1; 396 sdt_probetab = 397 kmem_zalloc(sdt_probetab_size * sizeof (sdt_probe_t *), KM_SLEEP); 398 dtrace_invop_add(sdt_invop); 399 400 for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) { 401 if (dtrace_register(prov->sdtp_name, prov->sdtp_attr, 402 DTRACE_PRIV_KERNEL, NULL, 403 &sdt_pops, prov, &prov->sdtp_id) != 0) { 404 cmn_err(CE_WARN, "failed to register sdt provider %s", 405 prov->sdtp_name); 406 } 407 } 408 409 return (DDI_SUCCESS); 410 } 411 412 /*ARGSUSED*/ 413 static int 414 sdt_detach(dev_info_t *dip, ddi_detach_cmd_t cmd) 415 { 416 sdt_provider_t *prov; 417 418 switch (cmd) { 419 case DDI_DETACH: 420 break; 421 422 case DDI_SUSPEND: 423 return (DDI_SUCCESS); 424 425 default: 426 return (DDI_FAILURE); 427 } 428 429 for (prov = sdt_providers; prov->sdtp_name != NULL; prov++) { 430 if (prov->sdtp_id != DTRACE_PROVNONE) { 431 if (dtrace_unregister(prov->sdtp_id) != 0) 432 return (DDI_FAILURE); 433 434 prov->sdtp_id = DTRACE_PROVNONE; 435 } 436 } 437 438 dtrace_invop_remove(sdt_invop); 439 kmem_free(sdt_probetab, sdt_probetab_size * sizeof (sdt_probe_t *)); 440 441 return (DDI_SUCCESS); 442 } 443 444 /*ARGSUSED*/ 445 static int 446 sdt_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result) 447 { 448 int error; 449 450 switch (infocmd) { 451 case DDI_INFO_DEVT2DEVINFO: 452 *result = (void *)sdt_devi; 453 error = DDI_SUCCESS; 454 break; 455 case DDI_INFO_DEVT2INSTANCE: 456 *result = (void *)0; 457 error = DDI_SUCCESS; 458 break; 459 default: 460 error = DDI_FAILURE; 461 } 462 return (error); 463 } 464 465 /*ARGSUSED*/ 466 static int 467 sdt_open(dev_t *devp, int flag, int otyp, cred_t *cred_p) 468 { 469 return (0); 470 } 471 472 static struct cb_ops sdt_cb_ops = { 473 sdt_open, /* open */ 474 nodev, /* close */ 475 nulldev, /* strategy */ 476 nulldev, /* print */ 477 nodev, /* dump */ 478 nodev, /* read */ 479 nodev, /* write */ 480 nodev, /* ioctl */ 481 nodev, /* devmap */ 482 nodev, /* mmap */ 483 nodev, /* segmap */ 484 nochpoll, /* poll */ 485 ddi_prop_op, /* cb_prop_op */ 486 0, /* streamtab */ 487 D_NEW | D_MP /* Driver compatibility flag */ 488 }; 489 490 static struct dev_ops sdt_ops = { 491 DEVO_REV, /* devo_rev, */ 492 0, /* refcnt */ 493 sdt_info, /* get_dev_info */ 494 nulldev, /* identify */ 495 nulldev, /* probe */ 496 sdt_attach, /* attach */ 497 sdt_detach, /* detach */ 498 nodev, /* reset */ 499 &sdt_cb_ops, /* driver operations */ 500 NULL, /* bus operations */ 501 nodev /* dev power */ 502 }; 503 504 /* 505 * Module linkage information for the kernel. 506 */ 507 static struct modldrv modldrv = { 508 &mod_driverops, /* module type (this is a pseudo driver) */ 509 "Statically Defined Tracing", /* name of module */ 510 &sdt_ops, /* driver ops */ 511 }; 512 513 static struct modlinkage modlinkage = { 514 MODREV_1, 515 (void *)&modldrv, 516 NULL 517 }; 518 519 int 520 _init(void) 521 { 522 return (mod_install(&modlinkage)); 523 } 524 525 int 526 _info(struct modinfo *modinfop) 527 { 528 return (mod_info(&modlinkage, modinfop)); 529 } 530 531 int 532 _fini(void) 533 { 534 return (mod_remove(&modlinkage)); 535 } 536