/*- * Copyright 2006-2008 John Birrell * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ * * Backend for the Statically Defined Tracing (SDT) kernel support. This is * required to allow a module to load even though DTrace kernel support may * not be present. A module may be built with SDT probes in it which are * registered and deregistered via SYSINIT/SYSUNINIT. * */ #include "opt_kdtrace.h" #include #include #include #include #include #include #include #include #include /* * This is the list of statically defined tracing providers. */ static TAILQ_HEAD(sdt_provider_list_head, sdt_provider) sdt_provider_list; /* * Mutex to serialise access to the SDT provider list. */ static struct sx sdt_sx; /* * Hook for the DTrace probe function. The 'sdt' provider will set this * to dtrace_probe when it loads. */ sdt_probe_func_t sdt_probe_func = sdt_probe_stub; /* * This is a stub for probe calls in case kernel DTrace support isn't * compiled in. It should never get called because there is no DTrace * support to enable it. */ void sdt_probe_stub(uint32_t id, uintptr_t arg0, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, uintptr_t arg4) { printf("sdt_probe_stub: Why did this get called?\n"); } /* * Called from SYSINIT to register a provider. */ void sdt_provider_register(void *arg) { struct sdt_provider *prov = arg; sx_xlock(&sdt_sx); TAILQ_INSERT_TAIL(&sdt_provider_list, prov, prov_entry); TAILQ_INIT(&prov->probe_list); sx_xunlock(&sdt_sx); } /* * Called from SYSUNINIT to de-register a provider. */ void sdt_provider_deregister(void *arg) { struct sdt_provider *prov = arg; sx_xlock(&sdt_sx); TAILQ_REMOVE(&sdt_provider_list, prov, prov_entry); sx_xunlock(&sdt_sx); } /* * Called from SYSINIT to register a statically defined trace probe. */ void sdt_probe_register(void *arg) { struct sdt_probe *probe = arg; /* * Check the reference structure version. Only version 1 is * supported at the moment. */ if (probe->version != sizeof(struct sdt_probe)) { printf("%s:%s:%s has version %d when %d required\n", probe->mod, probe->func, probe->name, probe->version, (int) sizeof(struct sdt_probe)); return; } sx_xlock(&sdt_sx); TAILQ_INSERT_TAIL(&probe->prov->probe_list, probe, probe_entry); TAILQ_INIT(&probe->argtype_list); probe->state = SDT_INIT; sx_xunlock(&sdt_sx); } /* * Called from SYSUNINIT to de-register a statically defined trace probe. */ void sdt_probe_deregister(void *arg) { struct sdt_probe *probe = arg; sx_xlock(&sdt_sx); if (probe->state == SDT_INIT) { TAILQ_REMOVE(&probe->prov->probe_list, probe, probe_entry); probe->state = SDT_UNINIT; } sx_xunlock(&sdt_sx); } /* * Called from SYSINIT to register a statically defined trace probe argument. */ void sdt_argtype_register(void *arg) { struct sdt_argtype *argtype = arg; sx_xlock(&sdt_sx); TAILQ_INSERT_TAIL(&argtype->probe->argtype_list, argtype, argtype_entry); argtype->probe->n_args++; sx_xunlock(&sdt_sx); } /* * Called from SYSUNINIT to de-register a statically defined trace probe argument. */ void sdt_argtype_deregister(void *arg) { struct sdt_argtype *argtype = arg; sx_xlock(&sdt_sx); TAILQ_REMOVE(&argtype->probe->argtype_list, argtype, argtype_entry); sx_xunlock(&sdt_sx); } static void sdt_init(void *arg) { sx_init_flags(&sdt_sx, "Statically Defined Tracing", SX_NOWITNESS); TAILQ_INIT(&sdt_provider_list); } SYSINIT(sdt, SI_SUB_KDTRACE, SI_ORDER_FIRST, sdt_init, NULL); static void sdt_uninit(void *arg) { sx_destroy(&sdt_sx); } SYSUNINIT(sdt, SI_SUB_KDTRACE, SI_ORDER_FIRST, sdt_uninit, NULL); /* * List statically defined tracing providers. */ int sdt_provider_listall(sdt_provider_listall_func_t callback_func,void *arg) { int error = 0; struct sdt_provider *prov; sx_xlock(&sdt_sx); TAILQ_FOREACH(prov, &sdt_provider_list, prov_entry) { if ((error = callback_func(prov, arg)) != 0) break; } sx_xunlock(&sdt_sx); return (error); } /* * List statically defined tracing probes. */ int sdt_probe_listall(struct sdt_provider *prov, sdt_probe_listall_func_t callback_func,void *arg) { int error = 0; int locked; struct sdt_probe *probe; locked = sx_xlocked(&sdt_sx); if (!locked) sx_xlock(&sdt_sx); TAILQ_FOREACH(probe, &prov->probe_list, probe_entry) { if ((error = callback_func(probe, arg)) != 0) break; } if (!locked) sx_xunlock(&sdt_sx); return (error); } /* * List statically defined tracing probe arguments. */ int sdt_argtype_listall(struct sdt_probe *probe, sdt_argtype_listall_func_t callback_func,void *arg) { int error = 0; int locked; struct sdt_argtype *argtype; locked = sx_xlocked(&sdt_sx); if (!locked) sx_xlock(&sdt_sx); TAILQ_FOREACH(argtype, &probe->argtype_list, argtype_entry) { if ((error = callback_func(argtype, arg)) != 0) break; } if (!locked) sx_xunlock(&sdt_sx); return (error); }