1179237Sjb/* 2179237Sjb * CDDL HEADER START 3179237Sjb * 4179237Sjb * The contents of this file are subject to the terms of the 5179237Sjb * Common Development and Distribution License (the "License"). 6179237Sjb * You may not use this file except in compliance with the License. 7179237Sjb * 8179237Sjb * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9179237Sjb * or http://www.opensolaris.org/os/licensing. 10179237Sjb * See the License for the specific language governing permissions 11179237Sjb * and limitations under the License. 12179237Sjb * 13179237Sjb * When distributing Covered Code, include this CDDL HEADER in each 14179237Sjb * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15179237Sjb * If applicable, add the following below this CDDL HEADER, with the 16179237Sjb * fields enclosed by brackets "[]" replaced with your own identifying 17179237Sjb * information: Portions Copyright [yyyy] [name of copyright owner] 18179237Sjb * 19179237Sjb * CDDL HEADER END 20179237Sjb * 21179237Sjb * Portions Copyright 2006-2008 John Birrell jb@freebsd.org 22179237Sjb * 23179237Sjb * $FreeBSD$ 24179237Sjb * 25179237Sjb */ 26179237Sjb 27262041Savg/* 28262041Savg * This file contains a reimplementation of the statically-defined tracing (SDT) 29262041Savg * framework for DTrace. Probes and SDT providers are defined using the macros 30262041Savg * in sys/sdt.h, which append all the needed structures to linker sets. When 31262041Savg * this module is loaded, it iterates over all of the loaded modules and 32262041Savg * registers probes and providers with the DTrace framework based on the 33262041Savg * contents of these linker sets. 34262041Savg * 35262041Savg * A list of SDT providers is maintained here since a provider may span multiple 36262041Savg * modules. When a kernel module is unloaded, a provider defined in that module 37262041Savg * is unregistered only if no other modules refer to it. The DTrace framework is 38262041Savg * responsible for destroying individual probes when a kernel module is 39262041Savg * unloaded; in particular, probes may not span multiple kernel modules. 40262041Savg */ 41262041Savg 42255763Smarkj#include "opt_kdtrace.h" 43179237Sjb 44179237Sjb#include <sys/cdefs.h> 45179237Sjb#include <sys/param.h> 46179237Sjb#include <sys/systm.h> 47255763Smarkj 48179237Sjb#include <sys/conf.h> 49255763Smarkj#include <sys/eventhandler.h> 50179237Sjb#include <sys/kernel.h> 51179237Sjb#include <sys/limits.h> 52255763Smarkj#include <sys/linker.h> 53255763Smarkj#include <sys/linker_set.h> 54179237Sjb#include <sys/lock.h> 55255763Smarkj#include <sys/malloc.h> 56179237Sjb#include <sys/module.h> 57179237Sjb#include <sys/mutex.h> 58255763Smarkj#include <sys/queue.h> 59255763Smarkj#include <sys/sdt.h> 60179237Sjb 61179237Sjb#include <sys/dtrace.h> 62255763Smarkj#include <sys/dtrace_bsd.h> 63179237Sjb 64255763Smarkj/* DTrace methods. */ 65179237Sjbstatic void sdt_getargdesc(void *, dtrace_id_t, void *, dtrace_argdesc_t *); 66179237Sjbstatic void sdt_provide_probes(void *, dtrace_probedesc_t *); 67179237Sjbstatic void sdt_destroy(void *, dtrace_id_t, void *); 68179237Sjbstatic void sdt_enable(void *, dtrace_id_t, void *); 69179237Sjbstatic void sdt_disable(void *, dtrace_id_t, void *); 70255763Smarkj 71262041Savgstatic void sdt_load(void); 72262041Savgstatic int sdt_unload(void); 73255763Smarkjstatic void sdt_create_provider(struct sdt_provider *); 74255763Smarkjstatic void sdt_create_probe(struct sdt_probe *); 75255763Smarkjstatic void sdt_kld_load(void *, struct linker_file *); 76262038Savgstatic void sdt_kld_unload_try(void *, struct linker_file *, int *); 77179237Sjb 78255763Smarkjstatic MALLOC_DEFINE(M_SDT, "SDT", "DTrace SDT providers"); 79255763Smarkj 80179237Sjbstatic dtrace_pattr_t sdt_attr = { 81179237Sjb{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, 82179237Sjb{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, 83179237Sjb{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA }, 84179237Sjb{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON }, 85179237Sjb{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA }, 86179237Sjb}; 87179237Sjb 88179237Sjbstatic dtrace_pops_t sdt_pops = { 89179237Sjb sdt_provide_probes, 90179237Sjb NULL, 91179237Sjb sdt_enable, 92179237Sjb sdt_disable, 93179237Sjb NULL, 94179237Sjb NULL, 95179237Sjb sdt_getargdesc, 96179237Sjb NULL, 97179237Sjb NULL, 98255763Smarkj sdt_destroy, 99179237Sjb}; 100179237Sjb 101255763Smarkjstatic TAILQ_HEAD(, sdt_provider) sdt_prov_list; 102255763Smarkj 103255763Smarkjeventhandler_tag sdt_kld_load_tag; 104262038Savgeventhandler_tag sdt_kld_unload_try_tag; 105255763Smarkj 106255763Smarkjstatic void 107255763Smarkjsdt_create_provider(struct sdt_provider *prov) 108179237Sjb{ 109255763Smarkj struct sdt_provider *curr, *newprov; 110179237Sjb 111255763Smarkj TAILQ_FOREACH(curr, &sdt_prov_list, prov_entry) 112255763Smarkj if (strcmp(prov->name, curr->name) == 0) { 113255763Smarkj /* The provider has already been defined. */ 114255763Smarkj curr->sdt_refs++; 115255763Smarkj return; 116255763Smarkj } 117179237Sjb 118255763Smarkj /* 119255763Smarkj * Make a copy of prov so that we don't lose fields if its module is 120255763Smarkj * unloaded but the provider isn't destroyed. This could happen with 121255763Smarkj * a provider that spans multiple modules. 122255763Smarkj */ 123255763Smarkj newprov = malloc(sizeof(*newprov), M_SDT, M_WAITOK | M_ZERO); 124255763Smarkj newprov->name = strdup(prov->name, M_SDT); 125255763Smarkj prov->sdt_refs = newprov->sdt_refs = 1; 126255763Smarkj 127255763Smarkj TAILQ_INSERT_TAIL(&sdt_prov_list, newprov, prov_entry); 128255763Smarkj 129255763Smarkj (void)dtrace_register(newprov->name, &sdt_attr, DTRACE_PRIV_USER, NULL, 130255763Smarkj &sdt_pops, NULL, (dtrace_provider_id_t *)&newprov->id); 131255763Smarkj prov->id = newprov->id; 132179237Sjb} 133179237Sjb 134179237Sjbstatic void 135255763Smarkjsdt_create_probe(struct sdt_probe *probe) 136179237Sjb{ 137255763Smarkj struct sdt_provider *prov; 138255763Smarkj char mod[DTRACE_MODNAMELEN]; 139255763Smarkj char func[DTRACE_FUNCNAMELEN]; 140255763Smarkj char name[DTRACE_NAMELEN]; 141262057Savg const char *from; 142262057Savg char *to; 143255763Smarkj size_t len; 144179237Sjb 145255763Smarkj TAILQ_FOREACH(prov, &sdt_prov_list, prov_entry) 146255763Smarkj if (strcmp(prov->name, probe->prov->name) == 0) 147255763Smarkj break; 148179237Sjb 149255763Smarkj KASSERT(prov != NULL, ("probe defined without a provider")); 150179237Sjb 151255763Smarkj /* If no module name was specified, use the module filename. */ 152255763Smarkj if (*probe->mod == 0) { 153255763Smarkj len = strlcpy(mod, probe->sdtp_lf->filename, sizeof(mod)); 154255763Smarkj if (len > 3 && strcmp(mod + len - 3, ".ko") == 0) 155255763Smarkj mod[len - 3] = '\0'; 156255763Smarkj } else 157255763Smarkj strlcpy(mod, probe->mod, sizeof(mod)); 158179237Sjb 159179237Sjb /* 160179237Sjb * Unfortunately this is necessary because the Solaris DTrace 161179237Sjb * code mixes consts and non-consts with casts to override 162179237Sjb * the incompatibilies. On FreeBSD, we use strict warnings 163255763Smarkj * in the C compiler, so we have to respect const vs non-const. 164179237Sjb */ 165179237Sjb strlcpy(func, probe->func, sizeof(func)); 166179237Sjb 167262057Savg from = probe->name; 168262057Savg to = name; 169262057Savg for (len = 0; len < (sizeof(name) - 1) && *from != '\0'; 170262057Savg len++, from++, to++) { 171262057Savg if (from[0] == '_' && from[1] == '_') { 172262057Savg *to = '-'; 173262057Savg from++; 174262057Savg } else 175262057Savg *to = *from; 176262057Savg } 177262057Savg *to = '\0'; 178262057Savg 179255763Smarkj if (dtrace_probe_lookup(prov->id, mod, func, name) != DTRACE_IDNONE) 180255763Smarkj return; 181179237Sjb 182255763Smarkj (void)dtrace_probe_create(prov->id, mod, func, name, 1, probe); 183179237Sjb} 184179237Sjb 185262041Savg/* 186262041Savg * Probes are created through the SDT module load/unload hook, so this function 187262041Savg * has nothing to do. It only exists because the DTrace provider framework 188262041Savg * requires one of provide_probes and provide_module to be defined. 189262041Savg */ 190255763Smarkjstatic void 191255763Smarkjsdt_provide_probes(void *arg, dtrace_probedesc_t *desc) 192179237Sjb{ 193179237Sjb} 194179237Sjb 195179237Sjbstatic void 196255763Smarkjsdt_enable(void *arg __unused, dtrace_id_t id, void *parg) 197179237Sjb{ 198255763Smarkj struct sdt_probe *probe = parg; 199179237Sjb 200255763Smarkj probe->id = id; 201255763Smarkj probe->sdtp_lf->nenabled++; 202179237Sjb} 203179237Sjb 204179237Sjbstatic void 205255763Smarkjsdt_disable(void *arg __unused, dtrace_id_t id, void *parg) 206179237Sjb{ 207255763Smarkj struct sdt_probe *probe = parg; 208255763Smarkj 209255763Smarkj KASSERT(probe->sdtp_lf->nenabled > 0, ("no probes enabled")); 210255763Smarkj 211255763Smarkj probe->id = 0; 212255763Smarkj probe->sdtp_lf->nenabled--; 213179237Sjb} 214179237Sjb 215179237Sjbstatic void 216255763Smarkjsdt_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc) 217179237Sjb{ 218255763Smarkj struct sdt_argtype *argtype; 219179237Sjb struct sdt_probe *probe = parg; 220179237Sjb 221262041Savg if (desc->dtargd_ndx >= probe->n_args) { 222262041Savg desc->dtargd_ndx = DTRACE_ARGNONE; 223262041Savg return; 224262041Savg } 225262041Savg 226262041Savg TAILQ_FOREACH(argtype, &probe->argtype_list, argtype_entry) { 227262041Savg if (desc->dtargd_ndx == argtype->ndx) { 228262041Savg desc->dtargd_mapping = desc->dtargd_ndx; 229262041Savg if (argtype->type == NULL) { 230262041Savg desc->dtargd_native[0] = '\0'; 231262041Savg desc->dtargd_xlate[0] = '\0'; 232262041Savg continue; 233255763Smarkj } 234262041Savg strlcpy(desc->dtargd_native, argtype->type, 235262041Savg sizeof(desc->dtargd_native)); 236262041Savg if (argtype->xtype != NULL) 237262041Savg strlcpy(desc->dtargd_xlate, argtype->xtype, 238262041Savg sizeof(desc->dtargd_xlate)); 239255763Smarkj } 240262041Savg } 241179237Sjb} 242179237Sjb 243179237Sjbstatic void 244255763Smarkjsdt_destroy(void *arg, dtrace_id_t id, void *parg) 245179237Sjb{ 246179237Sjb} 247179237Sjb 248255763Smarkj/* 249255763Smarkj * Called from the kernel linker when a module is loaded, before 250255763Smarkj * dtrace_module_loaded() is called. This is done so that it's possible to 251262041Savg * register new providers when modules are loaded. The DTrace framework 252262041Savg * explicitly disallows calling into the framework from the provide_module 253262041Savg * provider method, so we cannot do this there. 254255763Smarkj */ 255255763Smarkjstatic void 256255763Smarkjsdt_kld_load(void *arg __unused, struct linker_file *lf) 257255763Smarkj{ 258255763Smarkj struct sdt_provider **prov, **begin, **end; 259255763Smarkj struct sdt_probe **probe, **p_begin, **p_end; 260255763Smarkj struct sdt_argtype **argtype, **a_begin, **a_end; 261255763Smarkj 262255763Smarkj if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end, NULL)) 263255763Smarkj return; 264255763Smarkj for (prov = begin; prov < end; prov++) 265255763Smarkj sdt_create_provider(*prov); 266255763Smarkj 267255763Smarkj if (linker_file_lookup_set(lf, "sdt_probes_set", &p_begin, &p_end, 268255763Smarkj NULL)) 269255763Smarkj return; 270255763Smarkj for (probe = p_begin; probe < p_end; probe++) { 271255763Smarkj (*probe)->sdtp_lf = lf; 272255763Smarkj sdt_create_probe(*probe); 273255763Smarkj TAILQ_INIT(&(*probe)->argtype_list); 274255763Smarkj } 275255763Smarkj 276255763Smarkj if (linker_file_lookup_set(lf, "sdt_argtypes_set", &a_begin, &a_end, 277255763Smarkj NULL)) 278255763Smarkj return; 279255763Smarkj for (argtype = a_begin; argtype < a_end; argtype++) { 280255763Smarkj (*argtype)->probe->n_args++; 281255763Smarkj TAILQ_INSERT_TAIL(&(*argtype)->probe->argtype_list, *argtype, 282255763Smarkj argtype_entry); 283255763Smarkj } 284255763Smarkj} 285255763Smarkj 286255763Smarkjstatic void 287262041Savgsdt_kld_unload_try(void *arg __unused, struct linker_file *lf, int *error) 288255763Smarkj{ 289255763Smarkj struct sdt_provider *prov, **curr, **begin, **end, *tmp; 290255763Smarkj 291255763Smarkj if (*error != 0) 292255763Smarkj /* We already have an error, so don't do anything. */ 293255763Smarkj return; 294262041Savg else if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end, 295262041Savg NULL)) 296255763Smarkj /* No DTrace providers are declared in this file. */ 297255763Smarkj return; 298255763Smarkj 299255763Smarkj /* 300255763Smarkj * Go through all the providers declared in this linker file and 301255763Smarkj * unregister any that aren't declared in another loaded file. 302255763Smarkj */ 303255763Smarkj for (curr = begin; curr < end; curr++) { 304255763Smarkj TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) { 305262041Savg if (strcmp(prov->name, (*curr)->name) != 0) 306262041Savg continue; 307262041Savg 308262041Savg if (prov->sdt_refs == 1) { 309262041Savg if (dtrace_unregister(prov->id) != 0) { 310262041Savg *error = 1; 311262041Savg return; 312262041Savg } 313262041Savg TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry); 314262041Savg free(prov->name, M_SDT); 315262041Savg free(prov, M_SDT); 316262041Savg } else 317262041Savg prov->sdt_refs--; 318262041Savg break; 319255763Smarkj } 320255763Smarkj } 321255763Smarkj} 322255763Smarkj 323179237Sjbstatic int 324255763Smarkjsdt_linker_file_cb(linker_file_t lf, void *arg __unused) 325179237Sjb{ 326255763Smarkj 327255763Smarkj sdt_kld_load(NULL, lf); 328255763Smarkj 329255763Smarkj return (0); 330179237Sjb} 331179237Sjb 332179237Sjbstatic void 333262041Savgsdt_load() 334179237Sjb{ 335255763Smarkj 336255763Smarkj TAILQ_INIT(&sdt_prov_list); 337255763Smarkj 338179237Sjb sdt_probe_func = dtrace_probe; 339179237Sjb 340255763Smarkj sdt_kld_load_tag = EVENTHANDLER_REGISTER(kld_load, sdt_kld_load, NULL, 341255763Smarkj EVENTHANDLER_PRI_ANY); 342262038Savg sdt_kld_unload_try_tag = EVENTHANDLER_REGISTER(kld_unload_try, 343262038Savg sdt_kld_unload_try, NULL, EVENTHANDLER_PRI_ANY); 344179237Sjb 345255763Smarkj /* Pick up probes from the kernel and already-loaded linker files. */ 346255763Smarkj linker_file_foreach(sdt_linker_file_cb, NULL); 347179237Sjb} 348179237Sjb 349179237Sjbstatic int 350262041Savgsdt_unload() 351179237Sjb{ 352255763Smarkj struct sdt_provider *prov, *tmp; 353262041Savg int ret; 354179237Sjb 355255763Smarkj EVENTHANDLER_DEREGISTER(kld_load, sdt_kld_load_tag); 356262038Savg EVENTHANDLER_DEREGISTER(kld_unload_try, sdt_kld_unload_try_tag); 357255763Smarkj 358179237Sjb sdt_probe_func = sdt_probe_stub; 359179237Sjb 360255763Smarkj TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) { 361262041Savg ret = dtrace_unregister(prov->id); 362262041Savg if (ret != 0) 363262041Savg return (ret); 364255763Smarkj TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry); 365255763Smarkj free(prov->name, M_SDT); 366255763Smarkj free(prov, M_SDT); 367255763Smarkj } 368255763Smarkj 369255763Smarkj return (0); 370179237Sjb} 371179237Sjb 372179237Sjbstatic int 373179237Sjbsdt_modevent(module_t mod __unused, int type, void *data __unused) 374179237Sjb{ 375179237Sjb int error = 0; 376179237Sjb 377179237Sjb switch (type) { 378179237Sjb case MOD_LOAD: 379262041Savg sdt_load(); 380179237Sjb break; 381179237Sjb 382179237Sjb case MOD_UNLOAD: 383262041Savg error = sdt_unload(); 384179237Sjb break; 385179237Sjb 386179237Sjb case MOD_SHUTDOWN: 387179237Sjb break; 388179237Sjb 389179237Sjb default: 390179237Sjb error = EOPNOTSUPP; 391179237Sjb break; 392179237Sjb } 393179237Sjb 394179237Sjb return (error); 395179237Sjb} 396179237Sjb 397179237SjbDEV_MODULE(sdt, sdt_modevent, NULL); 398179237SjbMODULE_VERSION(sdt, 1); 399179237SjbMODULE_DEPEND(sdt, dtrace, 1, 1, 1); 400179237SjbMODULE_DEPEND(sdt, opensolaris, 1, 1, 1); 401