diff options
Diffstat (limited to 'sys/kern/kern_sdt.c')
| -rw-r--r-- | sys/kern/kern_sdt.c | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/sys/kern/kern_sdt.c b/sys/kern/kern_sdt.c new file mode 100644 index 0000000..ee4adde --- /dev/null +++ b/sys/kern/kern_sdt.c @@ -0,0 +1,339 @@ +/*- + * Copyright 2006-2008 John Birrell <jb@FreeBSD.org> + * + * 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 <sys/cdefs.h> +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/kernel.h> +#include <sys/linker.h> +#include <sys/lock.h> +#include <sys/proc.h> +#include <sys/sx.h> +#include <sys/sdt.h> + +/* + * 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; + +static sdt_provider_listall_func_t sdt_provider_register_func = NULL; +static sdt_provider_listall_func_t sdt_provider_deregister_func = NULL; +static sdt_probe_listall_func_t sdt_probe_register_func = NULL; + +static void *sdt_provider_register_arg; +static void *sdt_provider_deregister_arg; +static void *sdt_probe_register_arg; + +static int sdt_provider_listall_locked(sdt_provider_listall_func_t, void *); + +/* + * 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); + + if (sdt_provider_register_func != NULL) + sdt_provider_register_func(prov, sdt_provider_register_arg); + + 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); + + if (sdt_provider_deregister_func != NULL) + sdt_provider_deregister_func(prov, sdt_provider_deregister_arg); + + 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; + + if (sdt_probe_register_func != NULL) + sdt_probe_register_func(probe, sdt_provider_register_arg); + + 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; + + sx_xlock(&sdt_sx); + error = sdt_provider_listall_locked(callback_func, arg); + sx_xunlock(&sdt_sx); + + return (error); +} + +static int +sdt_provider_listall_locked(sdt_provider_listall_func_t callback_func, + void *arg) +{ + int error = 0; + struct sdt_provider *prov; + + sx_assert(&sdt_sx, SX_XLOCKED); + + TAILQ_FOREACH(prov, &sdt_provider_list, prov_entry) { + if ((error = callback_func(prov, arg)) != 0) + break; + } + + 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); +} + +void sdt_register_callbacks(sdt_provider_listall_func_t register_prov, + void *reg_prov_arg, sdt_provider_listall_func_t deregister_prov, + void *dereg_prov_arg, sdt_probe_listall_func_t register_probe, + void * reg_probe_arg) +{ + + sx_xlock(&sdt_sx); + sdt_provider_register_func = register_prov; + sdt_provider_deregister_func = deregister_prov; + sdt_probe_register_func = register_probe; + + sdt_provider_register_arg = reg_prov_arg; + sdt_provider_deregister_arg = dereg_prov_arg; + sdt_probe_register_arg = reg_probe_arg; + + sdt_provider_listall_locked(register_prov, reg_prov_arg); + sx_xunlock(&sdt_sx); +} + +void sdt_deregister_callbacks(void) +{ + + sx_xlock(&sdt_sx); + sdt_provider_listall_locked(sdt_provider_deregister_func, + sdt_provider_deregister_arg); + + sdt_provider_register_func = NULL; + sdt_provider_deregister_func = NULL; + sdt_probe_register_func = NULL; + + sdt_provider_register_arg = NULL; + sdt_provider_deregister_arg = NULL; + sdt_probe_register_arg = NULL; + sx_xunlock(&sdt_sx); +} |
