diff options
Diffstat (limited to 'src/VBox/ExtPacks/VBoxDTrace/onnv/uts/common/dtrace/fasttrap.c')
| -rw-r--r-- | src/VBox/ExtPacks/VBoxDTrace/onnv/uts/common/dtrace/fasttrap.c | 2378 |
1 files changed, 2378 insertions, 0 deletions
diff --git a/src/VBox/ExtPacks/VBoxDTrace/onnv/uts/common/dtrace/fasttrap.c b/src/VBox/ExtPacks/VBoxDTrace/onnv/uts/common/dtrace/fasttrap.c new file mode 100644 index 00000000..42263e4e --- /dev/null +++ b/src/VBox/ExtPacks/VBoxDTrace/onnv/uts/common/dtrace/fasttrap.c @@ -0,0 +1,2378 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ + +/* + * Copyright 2009 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + + +#include <sys/atomic.h> +#include <sys/errno.h> +#include <sys/stat.h> +#include <sys/modctl.h> +#include <sys/conf.h> +#include <sys/systm.h> +#include <sys/ddi.h> +#include <sys/sunddi.h> +#include <sys/cpuvar.h> +#include <sys/kmem.h> +#include <sys/strsubr.h> +#include <sys/fasttrap.h> +#include <sys/fasttrap_impl.h> +#include <sys/fasttrap_isa.h> +#include <sys/dtrace.h> +#include <sys/dtrace_impl.h> +#include <sys/sysmacros.h> +#include <sys/proc.h> +#include <sys/priv.h> +#include <sys/policy.h> +#include <util/qsort.h> + +/* + * User-Land Trap-Based Tracing + * ---------------------------- + * + * The fasttrap provider allows DTrace consumers to instrument any user-level + * instruction to gather data; this includes probes with semantic + * signifigance like entry and return as well as simple offsets into the + * function. While the specific techniques used are very ISA specific, the + * methodology is generalizable to any architecture. + * + * + * The General Methodology + * ----------------------- + * + * With the primary goal of tracing every user-land instruction and the + * limitation that we can't trust user space so don't want to rely on much + * information there, we begin by replacing the instructions we want to trace + * with trap instructions. Each instruction we overwrite is saved into a hash + * table keyed by process ID and pc address. When we enter the kernel due to + * this trap instruction, we need the effects of the replaced instruction to + * appear to have occurred before we proceed with the user thread's + * execution. + * + * Each user level thread is represented by a ulwp_t structure which is + * always easily accessible through a register. The most basic way to produce + * the effects of the instruction we replaced is to copy that instruction out + * to a bit of scratch space reserved in the user thread's ulwp_t structure + * (a sort of kernel-private thread local storage), set the PC to that + * scratch space and single step. When we reenter the kernel after single + * stepping the instruction we must then adjust the PC to point to what would + * normally be the next instruction. Of course, special care must be taken + * for branches and jumps, but these represent such a small fraction of any + * instruction set that writing the code to emulate these in the kernel is + * not too difficult. + * + * Return probes may require several tracepoints to trace every return site, + * and, conversely, each tracepoint may activate several probes (the entry + * and offset 0 probes, for example). To solve this muliplexing problem, + * tracepoints contain lists of probes to activate and probes contain lists + * of tracepoints to enable. If a probe is activated, it adds its ID to + * existing tracepoints or creates new ones as necessary. + * + * Most probes are activated _before_ the instruction is executed, but return + * probes are activated _after_ the effects of the last instruction of the + * function are visible. Return probes must be fired _after_ we have + * single-stepped the instruction whereas all other probes are fired + * beforehand. + * + * + * Lock Ordering + * ------------- + * + * The lock ordering below -- both internally and with respect to the DTrace + * framework -- is a little tricky and bears some explanation. Each provider + * has a lock (ftp_mtx) that protects its members including reference counts + * for enabled probes (ftp_rcount), consumers actively creating probes + * (ftp_ccount) and USDT consumers (ftp_mcount); all three prevent a provider + * from being freed. A provider is looked up by taking the bucket lock for the + * provider hash table, and is returned with its lock held. The provider lock + * may be taken in functions invoked by the DTrace framework, but may not be + * held while calling functions in the DTrace framework. + * + * To ensure consistency over multiple calls to the DTrace framework, the + * creation lock (ftp_cmtx) should be held. Naturally, the creation lock may + * not be taken when holding the provider lock as that would create a cyclic + * lock ordering. In situations where one would naturally take the provider + * lock and then the creation lock, we instead up a reference count to prevent + * the provider from disappearing, drop the provider lock, and acquire the + * creation lock. + * + * Briefly: + * bucket lock before provider lock + * DTrace before provider lock + * creation lock before DTrace + * never hold the provider lock and creation lock simultaneously + */ + +static dev_info_t *fasttrap_devi; +static dtrace_meta_provider_id_t fasttrap_meta_id; + +static timeout_id_t fasttrap_timeout; +static kmutex_t fasttrap_cleanup_mtx; +static uint_t fasttrap_cleanup_work; + +/* + * Generation count on modifications to the global tracepoint lookup table. + */ +static volatile uint64_t fasttrap_mod_gen; + +/* + * When the fasttrap provider is loaded, fasttrap_max is set to either + * FASTTRAP_MAX_DEFAULT or the value for fasttrap-max-probes in the + * fasttrap.conf file. Each time a probe is created, fasttrap_total is + * incremented by the number of tracepoints that may be associated with that + * probe; fasttrap_total is capped at fasttrap_max. + */ +#define FASTTRAP_MAX_DEFAULT 250000 +static uint32_t fasttrap_max; +static uint32_t fasttrap_total; + + +#define FASTTRAP_TPOINTS_DEFAULT_SIZE 0x4000 +#define FASTTRAP_PROVIDERS_DEFAULT_SIZE 0x100 +#define FASTTRAP_PROCS_DEFAULT_SIZE 0x100 + +#define FASTTRAP_PID_NAME "pid" + +fasttrap_hash_t fasttrap_tpoints; +static fasttrap_hash_t fasttrap_provs; +static fasttrap_hash_t fasttrap_procs; + +static uint64_t fasttrap_pid_count; /* pid ref count */ +static kmutex_t fasttrap_count_mtx; /* lock on ref count */ + +#define FASTTRAP_ENABLE_FAIL 1 +#define FASTTRAP_ENABLE_PARTIAL 2 + +static int fasttrap_tracepoint_enable(proc_t *, fasttrap_probe_t *, uint_t); +static void fasttrap_tracepoint_disable(proc_t *, fasttrap_probe_t *, uint_t); + +static fasttrap_provider_t *fasttrap_provider_lookup(pid_t, const char *, + const dtrace_pattr_t *); +static void fasttrap_provider_retire(pid_t, const char *, int); +static void fasttrap_provider_free(fasttrap_provider_t *); + +static fasttrap_proc_t *fasttrap_proc_lookup(pid_t); +static void fasttrap_proc_release(fasttrap_proc_t *); + +#define FASTTRAP_PROVS_INDEX(pid, name) \ + ((fasttrap_hash_str(name) + (pid)) & fasttrap_provs.fth_mask) + +#define FASTTRAP_PROCS_INDEX(pid) ((pid) & fasttrap_procs.fth_mask) + +static int +fasttrap_highbit(ulong_t i) +{ + int h = 1; + + if (i == 0) + return (0); +#ifdef _LP64 + if (i & 0xffffffff00000000ul) { + h += 32; i >>= 32; + } +#endif + if (i & 0xffff0000) { + h += 16; i >>= 16; + } + if (i & 0xff00) { + h += 8; i >>= 8; + } + if (i & 0xf0) { + h += 4; i >>= 4; + } + if (i & 0xc) { + h += 2; i >>= 2; + } + if (i & 0x2) { + h += 1; + } + return (h); +} + +static uint_t +fasttrap_hash_str(const char *p) +{ + unsigned int g; + uint_t hval = 0; + + while (*p) { + hval = (hval << 4) + *p++; + if ((g = (hval & 0xf0000000)) != 0) + hval ^= g >> 24; + hval &= ~g; + } + return (hval); +} + +void +fasttrap_sigtrap(proc_t *p, kthread_t *t, uintptr_t pc) +{ + sigqueue_t *sqp = kmem_zalloc(sizeof (sigqueue_t), KM_SLEEP); + + sqp->sq_info.si_signo = SIGTRAP; + sqp->sq_info.si_code = TRAP_DTRACE; + sqp->sq_info.si_addr = (caddr_t)pc; + + mutex_enter(&p->p_lock); + sigaddqa(p, t, sqp); + mutex_exit(&p->p_lock); + + if (t != NULL) + aston(t); +} + +/* + * This function ensures that no threads are actively using the memory + * associated with probes that were formerly live. + */ +static void +fasttrap_mod_barrier(uint64_t gen) +{ + int i; + + if (gen < fasttrap_mod_gen) + return; + + fasttrap_mod_gen++; + + for (i = 0; i < NCPU; i++) { + mutex_enter(&cpu_core[i].cpuc_pid_lock); + mutex_exit(&cpu_core[i].cpuc_pid_lock); + } +} + +/* + * This is the timeout's callback for cleaning up the providers and their + * probes. + */ +/*ARGSUSED*/ +static void +fasttrap_pid_cleanup_cb(void *data) +{ + fasttrap_provider_t **fpp, *fp; + fasttrap_bucket_t *bucket; + dtrace_provider_id_t provid; + int i, later; + + static volatile int in = 0; + ASSERT(in == 0); + in = 1; + + mutex_enter(&fasttrap_cleanup_mtx); + while (fasttrap_cleanup_work) { + fasttrap_cleanup_work = 0; + mutex_exit(&fasttrap_cleanup_mtx); + + later = 0; + + /* + * Iterate over all the providers trying to remove the marked + * ones. If a provider is marked but not retired, we just + * have to take a crack at removing it -- it's no big deal if + * we can't. + */ + for (i = 0; i < fasttrap_provs.fth_nent; i++) { + bucket = &fasttrap_provs.fth_table[i]; + mutex_enter(&bucket->ftb_mtx); + fpp = (fasttrap_provider_t **)&bucket->ftb_data; + + while ((fp = *fpp) != NULL) { + if (!fp->ftp_marked) { + fpp = &fp->ftp_next; + continue; + } + + mutex_enter(&fp->ftp_mtx); + + /* + * If this provider has consumers actively + * creating probes (ftp_ccount) or is a USDT + * provider (ftp_mcount), we can't unregister + * or even condense. + */ + if (fp->ftp_ccount != 0 || + fp->ftp_mcount != 0) { + mutex_exit(&fp->ftp_mtx); + fp->ftp_marked = 0; + continue; + } + + if (!fp->ftp_retired || fp->ftp_rcount != 0) + fp->ftp_marked = 0; + + mutex_exit(&fp->ftp_mtx); + + /* + * If we successfully unregister this + * provider we can remove it from the hash + * chain and free the memory. If our attempt + * to unregister fails and this is a retired + * provider, increment our flag to try again + * pretty soon. If we've consumed more than + * half of our total permitted number of + * probes call dtrace_condense() to try to + * clean out the unenabled probes. + */ + provid = fp->ftp_provid; + if (dtrace_unregister(provid) != 0) { + if (fasttrap_total > fasttrap_max / 2) + (void) dtrace_condense(provid); + later += fp->ftp_marked; + fpp = &fp->ftp_next; + } else { + *fpp = fp->ftp_next; + fasttrap_provider_free(fp); + } + } + mutex_exit(&bucket->ftb_mtx); + } + + mutex_enter(&fasttrap_cleanup_mtx); + } + + ASSERT(fasttrap_timeout != 0); + + /* + * If we were unable to remove a retired provider, try again after + * a second. This situation can occur in certain circumstances where + * providers cannot be unregistered even though they have no probes + * enabled because of an execution of dtrace -l or something similar. + * If the timeout has been disabled (set to 1 because we're trying + * to detach), we set fasttrap_cleanup_work to ensure that we'll + * get a chance to do that work if and when the timeout is reenabled + * (if detach fails). + */ + if (later > 0 && fasttrap_timeout != (timeout_id_t)1) + fasttrap_timeout = timeout(&fasttrap_pid_cleanup_cb, NULL, hz); + else if (later > 0) + fasttrap_cleanup_work = 1; + else + fasttrap_timeout = 0; + + mutex_exit(&fasttrap_cleanup_mtx); + in = 0; +} + +/* + * Activates the asynchronous cleanup mechanism. + */ +static void +fasttrap_pid_cleanup(void) +{ + mutex_enter(&fasttrap_cleanup_mtx); + fasttrap_cleanup_work = 1; + if (fasttrap_timeout == 0) + fasttrap_timeout = timeout(&fasttrap_pid_cleanup_cb, NULL, 1); + mutex_exit(&fasttrap_cleanup_mtx); +} + +/* + * This is called from cfork() via dtrace_fasttrap_fork(). The child + * process's address space is (roughly) a copy of the parent process's so + * we have to remove all the instrumentation we had previously enabled in the + * parent. + */ +static void +fasttrap_fork(proc_t *p, proc_t *cp) +{ + pid_t ppid = p->p_pid; + int i; + + ASSERT(curproc == p); + ASSERT(p->p_proc_flag & P_PR_LOCK); + ASSERT(p->p_dtrace_count > 0); + ASSERT(cp->p_dtrace_count == 0); + + /* + * This would be simpler and faster if we maintained per-process + * hash tables of enabled tracepoints. It could, however, potentially + * slow down execution of a tracepoint since we'd need to go + * through two levels of indirection. In the future, we should + * consider either maintaining per-process ancillary lists of + * enabled tracepoints or hanging a pointer to a per-process hash + * table of enabled tracepoints off the proc structure. + */ + + /* + * We don't have to worry about the child process disappearing + * because we're in fork(). + */ + mutex_enter(&cp->p_lock); + sprlock_proc(cp); + mutex_exit(&cp->p_lock); + + /* + * Iterate over every tracepoint looking for ones that belong to the + * parent process, and remove each from the child process. + */ + for (i = 0; i < fasttrap_tpoints.fth_nent; i++) { + fasttrap_tracepoint_t *tp; + fasttrap_bucket_t *bucket = &fasttrap_tpoints.fth_table[i]; + + mutex_enter(&bucket->ftb_mtx); + for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) { + if (tp->ftt_pid == ppid && + tp->ftt_proc->ftpc_acount != 0) { + int ret = fasttrap_tracepoint_remove(cp, tp); + ASSERT(ret == 0); + + /* + * The count of active providers can only be + * decremented (i.e. to zero) during exec, + * exit, and removal of a meta provider so it + * should be impossible to drop the count + * mid-fork. + */ + ASSERT(tp->ftt_proc->ftpc_acount != 0); + } + } + mutex_exit(&bucket->ftb_mtx); + } + + mutex_enter(&cp->p_lock); + sprunlock(cp); +} + +/* + * This is called from proc_exit() or from exec_common() if p_dtrace_probes + * is set on the proc structure to indicate that there is a pid provider + * associated with this process. + */ +static void +fasttrap_exec_exit(proc_t *p) +{ + ASSERT(p == curproc); + ASSERT(MUTEX_HELD(&p->p_lock)); + + mutex_exit(&p->p_lock); + + /* + * We clean up the pid provider for this process here; user-land + * static probes are handled by the meta-provider remove entry point. + */ + fasttrap_provider_retire(p->p_pid, FASTTRAP_PID_NAME, 0); + + mutex_enter(&p->p_lock); +} + + +/*ARGSUSED*/ +static void +fasttrap_pid_provide(void *arg, const dtrace_probedesc_t *desc) +{ + /* + * There are no "default" pid probes. + */ +} + +static int +fasttrap_tracepoint_enable(proc_t *p, fasttrap_probe_t *probe, uint_t index) +{ + fasttrap_tracepoint_t *tp, *new_tp = NULL; + fasttrap_bucket_t *bucket; + fasttrap_id_t *id; + pid_t pid; + uintptr_t pc; + + ASSERT(index < probe->ftp_ntps); + + pid = probe->ftp_pid; + pc = probe->ftp_tps[index].fit_tp->ftt_pc; + id = &probe->ftp_tps[index].fit_id; + + ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid); + + ASSERT(!(p->p_flag & SVFORK)); + + /* + * Before we make any modifications, make sure we've imposed a barrier + * on the generation in which this probe was last modified. + */ + fasttrap_mod_barrier(probe->ftp_gen); + + bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)]; + + /* + * If the tracepoint has already been enabled, just add our id to the + * list of interested probes. This may be our second time through + * this path in which case we'll have constructed the tracepoint we'd + * like to install. If we can't find a match, and have an allocated + * tracepoint ready to go, enable that one now. + * + * A tracepoint whose process is defunct is also considered defunct. + */ +again: + mutex_enter(&bucket->ftb_mtx); + for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) { + /* + * Note that it's safe to access the active count on the + * associated proc structure because we know that at least one + * provider (this one) will still be around throughout this + * operation. + */ + if (tp->ftt_pid != pid || tp->ftt_pc != pc || + tp->ftt_proc->ftpc_acount == 0) + continue; + + /* + * Now that we've found a matching tracepoint, it would be + * a decent idea to confirm that the tracepoint is still + * enabled and the trap instruction hasn't been overwritten. + * Since this is a little hairy, we'll punt for now. + */ + + /* + * This can't be the first interested probe. We don't have + * to worry about another thread being in the midst of + * deleting this tracepoint (which would be the only valid + * reason for a tracepoint to have no interested probes) + * since we're holding P_PR_LOCK for this process. + */ + ASSERT(tp->ftt_ids != NULL || tp->ftt_retids != NULL); + + switch (id->fti_ptype) { + case DTFTP_ENTRY: + case DTFTP_OFFSETS: + case DTFTP_IS_ENABLED: + id->fti_next = tp->ftt_ids; + membar_producer(); + tp->ftt_ids = id; + membar_producer(); + break; + + case DTFTP_RETURN: + case DTFTP_POST_OFFSETS: + id->fti_next = tp->ftt_retids; + membar_producer(); + tp->ftt_retids = id; + membar_producer(); + break; + + default: + ASSERT(0); + } + + mutex_exit(&bucket->ftb_mtx); + + if (new_tp != NULL) { + new_tp->ftt_ids = NULL; + new_tp->ftt_retids = NULL; + } + + return (0); + } + + /* + * If we have a good tracepoint ready to go, install it now while + * we have the lock held and no one can screw with us. + */ + if (new_tp != NULL) { + int rc = 0; + + new_tp->ftt_next = bucket->ftb_data; + membar_producer(); + bucket->ftb_data = new_tp; + membar_producer(); + mutex_exit(&bucket->ftb_mtx); + + /* + * Activate the tracepoint in the ISA-specific manner. + * If this fails, we need to report the failure, but + * indicate that this tracepoint must still be disabled + * by calling fasttrap_tracepoint_disable(). + */ + if (fasttrap_tracepoint_install(p, new_tp) != 0) + rc = FASTTRAP_ENABLE_PARTIAL; + + /* + * Increment the count of the number of tracepoints active in + * the victim process. + */ + ASSERT(p->p_proc_flag & P_PR_LOCK); + p->p_dtrace_count++; + + return (rc); + } + + mutex_exit(&bucket->ftb_mtx); + + /* + * Initialize the tracepoint that's been preallocated with the probe. + */ + new_tp = probe->ftp_tps[index].fit_tp; + + ASSERT(new_tp->ftt_pid == pid); + ASSERT(new_tp->ftt_pc == pc); + ASSERT(new_tp->ftt_proc == probe->ftp_prov->ftp_proc); + ASSERT(new_tp->ftt_ids == NULL); + ASSERT(new_tp->ftt_retids == NULL); + + switch (id->fti_ptype) { + case DTFTP_ENTRY: + case DTFTP_OFFSETS: + case DTFTP_IS_ENABLED: + id->fti_next = NULL; + new_tp->ftt_ids = id; + break; + + case DTFTP_RETURN: + case DTFTP_POST_OFFSETS: + id->fti_next = NULL; + new_tp->ftt_retids = id; + break; + + default: + ASSERT(0); + } + + /* + * If the ISA-dependent initialization goes to plan, go back to the + * beginning and try to install this freshly made tracepoint. + */ + if (fasttrap_tracepoint_init(p, new_tp, pc, id->fti_ptype) == 0) + goto again; + + new_tp->ftt_ids = NULL; + new_tp->ftt_retids = NULL; + + return (FASTTRAP_ENABLE_FAIL); +} + +static void +fasttrap_tracepoint_disable(proc_t *p, fasttrap_probe_t *probe, uint_t index) +{ + fasttrap_bucket_t *bucket; + fasttrap_provider_t *provider = probe->ftp_prov; + fasttrap_tracepoint_t **pp, *tp; + fasttrap_id_t *id, **idp; + pid_t pid; + uintptr_t pc; + + ASSERT(index < probe->ftp_ntps); + + pid = probe->ftp_pid; + pc = probe->ftp_tps[index].fit_tp->ftt_pc; + id = &probe->ftp_tps[index].fit_id; + + ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid); + + /* + * Find the tracepoint and make sure that our id is one of the + * ones registered with it. + */ + bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)]; + mutex_enter(&bucket->ftb_mtx); + for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) { + if (tp->ftt_pid == pid && tp->ftt_pc == pc && + tp->ftt_proc == provider->ftp_proc) + break; + } + + /* + * If we somehow lost this tracepoint, we're in a world of hurt. + */ + ASSERT(tp != NULL); + + switch (id->fti_ptype) { + case DTFTP_ENTRY: + case DTFTP_OFFSETS: + case DTFTP_IS_ENABLED: + ASSERT(tp->ftt_ids != NULL); + idp = &tp->ftt_ids; + break; + + case DTFTP_RETURN: + case DTFTP_POST_OFFSETS: + ASSERT(tp->ftt_retids != NULL); + idp = &tp->ftt_retids; + break; + + default: + ASSERT(0); + } + + while ((*idp)->fti_probe != probe) { + idp = &(*idp)->fti_next; + ASSERT(*idp != NULL); + } + + id = *idp; + *idp = id->fti_next; + membar_producer(); + + ASSERT(id->fti_probe == probe); + + /* + * If there are other registered enablings of this tracepoint, we're + * all done, but if this was the last probe assocated with this + * this tracepoint, we need to remove and free it. + */ + if (tp->ftt_ids != NULL || tp->ftt_retids != NULL) { + + /* + * If the current probe's tracepoint is in use, swap it + * for an unused tracepoint. + */ + if (tp == probe->ftp_tps[index].fit_tp) { + fasttrap_probe_t *tmp_probe; + fasttrap_tracepoint_t **tmp_tp; + uint_t tmp_index; + + if (tp->ftt_ids != NULL) { + tmp_probe = tp->ftt_ids->fti_probe; + /* LINTED - alignment */ + tmp_index = FASTTRAP_ID_INDEX(tp->ftt_ids); + tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp; + } else { + tmp_probe = tp->ftt_retids->fti_probe; + /* LINTED - alignment */ + tmp_index = FASTTRAP_ID_INDEX(tp->ftt_retids); + tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp; + } + + ASSERT(*tmp_tp != NULL); + ASSERT(*tmp_tp != probe->ftp_tps[index].fit_tp); + ASSERT((*tmp_tp)->ftt_ids == NULL); + ASSERT((*tmp_tp)->ftt_retids == NULL); + + probe->ftp_tps[index].fit_tp = *tmp_tp; + *tmp_tp = tp; + } + + mutex_exit(&bucket->ftb_mtx); + + /* + * Tag the modified probe with the generation in which it was + * changed. + */ + probe->ftp_gen = fasttrap_mod_gen; + return; + } + + mutex_exit(&bucket->ftb_mtx); + + /* + * We can't safely remove the tracepoint from the set of active + * tracepoints until we've actually removed the fasttrap instruction + * from the process's text. We can, however, operate on this + * tracepoint secure in the knowledge that no other thread is going to + * be looking at it since we hold P_PR_LOCK on the process if it's + * live or we hold the provider lock on the process if it's dead and + * gone. + */ + + /* + * We only need to remove the actual instruction if we're looking + * at an existing process + */ + if (p != NULL) { + /* + * If we fail to restore the instruction we need to kill + * this process since it's in a completely unrecoverable + * state. + */ + if (fasttrap_tracepoint_remove(p, tp) != 0) + fasttrap_sigtrap(p, NULL, pc); + + /* + * Decrement the count of the number of tracepoints active + * in the victim process. + */ + ASSERT(p->p_proc_flag & P_PR_LOCK); + p->p_dtrace_count--; + } + + /* + * Remove the probe from the hash table of active tracepoints. + */ + mutex_enter(&bucket->ftb_mtx); + pp = (fasttrap_tracepoint_t **)&bucket->ftb_data; + ASSERT(*pp != NULL); + while (*pp != tp) { + pp = &(*pp)->ftt_next; + ASSERT(*pp != NULL); + } + + *pp = tp->ftt_next; + membar_producer(); + + mutex_exit(&bucket->ftb_mtx); + + /* + * Tag the modified probe with the generation in which it was changed. + */ + probe->ftp_gen = fasttrap_mod_gen; +} + +static void +fasttrap_enable_callbacks(void) +{ + /* + * We don't have to play the rw lock game here because we're + * providing something rather than taking something away -- + * we can be sure that no threads have tried to follow this + * function pointer yet. + */ + mutex_enter(&fasttrap_count_mtx); + if (fasttrap_pid_count == 0) { + ASSERT(dtrace_pid_probe_ptr == NULL); + ASSERT(dtrace_return_probe_ptr == NULL); + dtrace_pid_probe_ptr = &fasttrap_pid_probe; + dtrace_return_probe_ptr = &fasttrap_return_probe; + } + ASSERT(dtrace_pid_probe_ptr == &fasttrap_pid_probe); + ASSERT(dtrace_return_probe_ptr == &fasttrap_return_probe); + fasttrap_pid_count++; + mutex_exit(&fasttrap_count_mtx); +} + +static void +fasttrap_disable_callbacks(void) +{ + ASSERT(MUTEX_HELD(&cpu_lock)); + + mutex_enter(&fasttrap_count_mtx); + ASSERT(fasttrap_pid_count > 0); + fasttrap_pid_count--; + if (fasttrap_pid_count == 0) { + cpu_t *cur, *cpu = CPU; + + for (cur = cpu->cpu_next_onln; cur != cpu; + cur = cur->cpu_next_onln) { + rw_enter(&cur->cpu_ft_lock, RW_WRITER); + } + + dtrace_pid_probe_ptr = NULL; + dtrace_return_probe_ptr = NULL; + + for (cur = cpu->cpu_next_onln; cur != cpu; + cur = cur->cpu_next_onln) { + rw_exit(&cur->cpu_ft_lock); + } + } + mutex_exit(&fasttrap_count_mtx); +} + +/*ARGSUSED*/ +static int +fasttrap_pid_enable(void *arg, dtrace_id_t id, void *parg) +{ + fasttrap_probe_t *probe = parg; + proc_t *p; + int i, rc; + + ASSERT(probe != NULL); + ASSERT(!probe->ftp_enabled); + ASSERT(id == probe->ftp_id); + ASSERT(MUTEX_HELD(&cpu_lock)); + + /* + * Increment the count of enabled probes on this probe's provider; + * the provider can't go away while the probe still exists. We + * must increment this even if we aren't able to properly enable + * this probe. + */ + mutex_enter(&probe->ftp_prov->ftp_mtx); + probe->ftp_prov->ftp_rcount++; + mutex_exit(&probe->ftp_prov->ftp_mtx); + + /* + * If this probe's provider is retired (meaning it was valid in a + * previously exec'ed incarnation of this address space), bail out. The + * provider can't go away while we're in this code path. + */ + if (probe->ftp_prov->ftp_retired) + return (0); + + /* + * If we can't find the process, it may be that we're in the context of + * a fork in which the traced process is being born and we're copying + * USDT probes. Otherwise, the process is gone so bail. + */ + if ((p = sprlock(probe->ftp_pid)) == NULL) { + if ((curproc->p_flag & SFORKING) == 0) + return (0); + + mutex_enter(&pidlock); + p = prfind(probe->ftp_pid); + + /* + * Confirm that curproc is indeed forking the process in which + * we're trying to enable probes. + */ + ASSERT(p != NULL); + ASSERT(p->p_parent == curproc); + ASSERT(p->p_stat == SIDL); + + mutex_enter(&p->p_lock); + mutex_exit(&pidlock); + + sprlock_proc(p); + } + + ASSERT(!(p->p_flag & SVFORK)); + mutex_exit(&p->p_lock); + + /* + * We have to enable the trap entry point before any user threads have + * the chance to execute the trap instruction we're about to place + * in their process's text. + */ + fasttrap_enable_callbacks(); + + /* + * Enable all the tracepoints and add this probe's id to each + * tracepoint's list of active probes. + */ + for (i = 0; i < probe->ftp_ntps; i++) { + if ((rc = fasttrap_tracepoint_enable(p, probe, i)) != 0) { + /* + * If enabling the tracepoint failed completely, + * we don't have to disable it; if the failure + * was only partial we must disable it. + */ + if (rc == FASTTRAP_ENABLE_FAIL) + i--; + else + ASSERT(rc == FASTTRAP_ENABLE_PARTIAL); + + /* + * Back up and pull out all the tracepoints we've + * created so far for this probe. + */ + while (i >= 0) { + fasttrap_tracepoint_disable(p, probe, i); + i--; + } + + mutex_enter(&p->p_lock); + sprunlock(p); + + /* + * Since we're not actually enabling this probe, + * drop our reference on the trap table entry. + */ + fasttrap_disable_callbacks(); + return (0); + } + } + + mutex_enter(&p->p_lock); + sprunlock(p); + + probe->ftp_enabled = 1; + return (0); +} + +/*ARGSUSED*/ +static void +fasttrap_pid_disable(void *arg, dtrace_id_t id, void *parg) +{ + fasttrap_probe_t *probe = parg; + fasttrap_provider_t *provider = probe->ftp_prov; + proc_t *p; + int i, whack = 0; + + ASSERT(id == probe->ftp_id); + + /* + * We won't be able to acquire a /proc-esque lock on the process + * iff the process is dead and gone. In this case, we rely on the + * provider lock as a point of mutual exclusion to prevent other + * DTrace consumers from disabling this probe. + */ + if ((p = sprlock(probe->ftp_pid)) != NULL) { + ASSERT(!(p->p_flag & SVFORK)); + mutex_exit(&p->p_lock); + } + + mutex_enter(&provider->ftp_mtx); + + /* + * Disable all the associated tracepoints (for fully enabled probes). + */ + if (probe->ftp_enabled) { + for (i = 0; i < probe->ftp_ntps; i++) { + fasttrap_tracepoint_disable(p, probe, i); + } + } + + ASSERT(provider->ftp_rcount > 0); + provider->ftp_rcount--; + + if (p != NULL) { + /* + * Even though we may not be able to remove it entirely, we + * mark this retired provider to get a chance to remove some + * of the associated probes. + */ + if (provider->ftp_retired && !provider->ftp_marked) + whack = provider->ftp_marked = 1; + mutex_exit(&provider->ftp_mtx); + + mutex_enter(&p->p_lock); + sprunlock(p); + } else { + /* + * If the process is dead, we're just waiting for the + * last probe to be disabled to be able to free it. + */ + if (provider->ftp_rcount == 0 && !provider->ftp_marked) + whack = provider->ftp_marked = 1; + mutex_exit(&provider->ftp_mtx); + } + + if (whack) + fasttrap_pid_cleanup(); + + if (!probe->ftp_enabled) + return; + + probe->ftp_enabled = 0; + + ASSERT(MUTEX_HELD(&cpu_lock)); + fasttrap_disable_callbacks(); +} + +/*ARGSUSED*/ +static void +fasttrap_pid_getargdesc(void *arg, dtrace_id_t id, void *parg, + dtrace_argdesc_t *desc) +{ + fasttrap_probe_t *probe = parg; + char *str; + int i, ndx; + + desc->dtargd_native[0] = '\0'; + desc->dtargd_xlate[0] = '\0'; + + if (probe->ftp_prov->ftp_retired != 0 || + desc->dtargd_ndx >= probe->ftp_nargs) { + desc->dtargd_ndx = DTRACE_ARGNONE; + return; + } + + ndx = (probe->ftp_argmap != NULL) ? + probe->ftp_argmap[desc->dtargd_ndx] : desc->dtargd_ndx; + + str = probe->ftp_ntypes; + for (i = 0; i < ndx; i++) { + str += strlen(str) + 1; + } + + ASSERT(strlen(str + 1) < sizeof (desc->dtargd_native)); + (void) strcpy(desc->dtargd_native, str); + + if (probe->ftp_xtypes == NULL) + return; + + str = probe->ftp_xtypes; + for (i = 0; i < desc->dtargd_ndx; i++) { + str += strlen(str) + 1; + } + + ASSERT(strlen(str + 1) < sizeof (desc->dtargd_xlate)); + (void) strcpy(desc->dtargd_xlate, str); +} + +/*ARGSUSED*/ +static void +fasttrap_pid_destroy(void *arg, dtrace_id_t id, void *parg) +{ + fasttrap_probe_t *probe = parg; + int i; + size_t size; + + ASSERT(probe != NULL); + ASSERT(!probe->ftp_enabled); + ASSERT(fasttrap_total >= probe->ftp_ntps); + + atomic_add_32(&fasttrap_total, -probe->ftp_ntps); + size = offsetof(fasttrap_probe_t, ftp_tps[probe->ftp_ntps]); + + if (probe->ftp_gen + 1 >= fasttrap_mod_gen) + fasttrap_mod_barrier(probe->ftp_gen); + + for (i = 0; i < probe->ftp_ntps; i++) { + kmem_free(probe->ftp_tps[i].fit_tp, + sizeof (fasttrap_tracepoint_t)); + } + + kmem_free(probe, size); +} + + +static const dtrace_pattr_t pid_attr = { +{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA }, +{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, +{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, +{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA }, +{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN }, +}; + +static dtrace_pops_t pid_pops = { + fasttrap_pid_provide, + NULL, + fasttrap_pid_enable, + fasttrap_pid_disable, + NULL, + NULL, + fasttrap_pid_getargdesc, + fasttrap_pid_getarg, + NULL, + fasttrap_pid_destroy +}; + +static dtrace_pops_t usdt_pops = { + fasttrap_pid_provide, + NULL, + fasttrap_pid_enable, + fasttrap_pid_disable, + NULL, + NULL, + fasttrap_pid_getargdesc, + fasttrap_usdt_getarg, + NULL, + fasttrap_pid_destroy +}; + +static fasttrap_proc_t * +fasttrap_proc_lookup(pid_t pid) +{ + fasttrap_bucket_t *bucket; + fasttrap_proc_t *fprc, *new_fprc; + + bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)]; + mutex_enter(&bucket->ftb_mtx); + + for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) { + if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) { + mutex_enter(&fprc->ftpc_mtx); + mutex_exit(&bucket->ftb_mtx); + fprc->ftpc_rcount++; + atomic_add_64(&fprc->ftpc_acount, 1); + ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount); + mutex_exit(&fprc->ftpc_mtx); + + return (fprc); + } + } + + /* + * Drop the bucket lock so we don't try to perform a sleeping + * allocation under it. + */ + mutex_exit(&bucket->ftb_mtx); + + new_fprc = kmem_zalloc(sizeof (fasttrap_proc_t), KM_SLEEP); + new_fprc->ftpc_pid = pid; + new_fprc->ftpc_rcount = 1; + new_fprc->ftpc_acount = 1; + + mutex_enter(&bucket->ftb_mtx); + + /* + * Take another lap through the list to make sure a proc hasn't + * been created for this pid while we weren't under the bucket lock. + */ + for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) { + if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) { + mutex_enter(&fprc->ftpc_mtx); + mutex_exit(&bucket->ftb_mtx); + fprc->ftpc_rcount++; + atomic_add_64(&fprc->ftpc_acount, 1); + ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount); + mutex_exit(&fprc->ftpc_mtx); + + kmem_free(new_fprc, sizeof (fasttrap_proc_t)); + + return (fprc); + } + } + + new_fprc->ftpc_next = bucket->ftb_data; + bucket->ftb_data = new_fprc; + + mutex_exit(&bucket->ftb_mtx); + + return (new_fprc); +} + +static void +fasttrap_proc_release(fasttrap_proc_t *proc) +{ + fasttrap_bucket_t *bucket; + fasttrap_proc_t *fprc, **fprcp; + pid_t pid = proc->ftpc_pid; + + mutex_enter(&proc->ftpc_mtx); + + ASSERT(proc->ftpc_rcount != 0); + ASSERT(proc->ftpc_acount <= proc->ftpc_rcount); + + if (--proc->ftpc_rcount != 0) { + mutex_exit(&proc->ftpc_mtx); + return; + } + + mutex_exit(&proc->ftpc_mtx); + + /* + * There should definitely be no live providers associated with this + * process at this point. + */ + ASSERT(proc->ftpc_acount == 0); + + bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)]; + mutex_enter(&bucket->ftb_mtx); + + fprcp = (fasttrap_proc_t **)&bucket->ftb_data; + while ((fprc = *fprcp) != NULL) { + if (fprc == proc) + break; + + fprcp = &fprc->ftpc_next; + } + + /* + * Something strange has happened if we can't find the proc. + */ + ASSERT(fprc != NULL); + + *fprcp = fprc->ftpc_next; + + mutex_exit(&bucket->ftb_mtx); + + kmem_free(fprc, sizeof (fasttrap_proc_t)); +} + +/* + * Lookup a fasttrap-managed provider based on its name and associated pid. + * If the pattr argument is non-NULL, this function instantiates the provider + * if it doesn't exist otherwise it returns NULL. The provider is returned + * with its lock held. + */ +static fasttrap_provider_t * +fasttrap_provider_lookup(pid_t pid, const char *name, + const dtrace_pattr_t *pattr) +{ + fasttrap_provider_t *fp, *new_fp = NULL; + fasttrap_bucket_t *bucket; + char provname[DTRACE_PROVNAMELEN]; + proc_t *p; + cred_t *cred; + + ASSERT(strlen(name) < sizeof (fp->ftp_name)); + ASSERT(pattr != NULL); + + bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)]; + mutex_enter(&bucket->ftb_mtx); + + /* + * Take a lap through the list and return the match if we find it. + */ + for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) { + if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 && + !fp->ftp_retired) { + mutex_enter(&fp->ftp_mtx); + mutex_exit(&bucket->ftb_mtx); + return (fp); + } + } + + /* + * Drop the bucket lock so we don't try to perform a sleeping + * allocation under it. + */ + mutex_exit(&bucket->ftb_mtx); + + /* + * Make sure the process exists, isn't a child created as the result + * of a vfork(2), and isn't a zombie (but may be in fork). + */ + mutex_enter(&pidlock); + if ((p = prfind(pid)) == NULL) { + mutex_exit(&pidlock); + return (NULL); + } + mutex_enter(&p->p_lock); + mutex_exit(&pidlock); + if (p->p_flag & (SVFORK | SEXITING)) { + mutex_exit(&p->p_lock); + return (NULL); + } + + /* + * Increment p_dtrace_probes so that the process knows to inform us + * when it exits or execs. fasttrap_provider_free() decrements this + * when we're done with this provider. + */ + p->p_dtrace_probes++; + + /* + * Grab the credentials for this process so we have + * something to pass to dtrace_register(). + */ + mutex_enter(&p->p_crlock); + crhold(p->p_cred); + cred = p->p_cred; + mutex_exit(&p->p_crlock); + mutex_exit(&p->p_lock); + + new_fp = kmem_zalloc(sizeof (fasttrap_provider_t), KM_SLEEP); + new_fp->ftp_pid = pid; + new_fp->ftp_proc = fasttrap_proc_lookup(pid); + + ASSERT(new_fp->ftp_proc != NULL); + + mutex_enter(&bucket->ftb_mtx); + + /* + * Take another lap through the list to make sure a provider hasn't + * been created for this pid while we weren't under the bucket lock. + */ + for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) { + if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 && + !fp->ftp_retired) { + mutex_enter(&fp->ftp_mtx); + mutex_exit(&bucket->ftb_mtx); + fasttrap_provider_free(new_fp); + crfree(cred); + return (fp); + } + } + + (void) strcpy(new_fp->ftp_name, name); + + /* + * Fail and return NULL if either the provider name is too long + * or we fail to register this new provider with the DTrace + * framework. Note that this is the only place we ever construct + * the full provider name -- we keep it in pieces in the provider + * structure. + */ + if (snprintf(provname, sizeof (provname), "%s%u", name, (uint_t)pid) >= + sizeof (provname) || + dtrace_register(provname, pattr, + DTRACE_PRIV_PROC | DTRACE_PRIV_OWNER | DTRACE_PRIV_ZONEOWNER, cred, + pattr == &pid_attr ? &pid_pops : &usdt_pops, new_fp, + &new_fp->ftp_provid) != 0) { + mutex_exit(&bucket->ftb_mtx); + fasttrap_provider_free(new_fp); + crfree(cred); + return (NULL); + } + + new_fp->ftp_next = bucket->ftb_data; + bucket->ftb_data = new_fp; + + mutex_enter(&new_fp->ftp_mtx); + mutex_exit(&bucket->ftb_mtx); + + crfree(cred); + return (new_fp); +} + +static void +fasttrap_provider_free(fasttrap_provider_t *provider) +{ + pid_t pid = provider->ftp_pid; + proc_t *p; + + /* + * There need to be no associated enabled probes, no consumers + * creating probes, and no meta providers referencing this provider. + */ + ASSERT(provider->ftp_rcount == 0); + ASSERT(provider->ftp_ccount == 0); + ASSERT(provider->ftp_mcount == 0); + + /* + * If this provider hasn't been retired, we need to explicitly drop the + * count of active providers on the associated process structure. + */ + if (!provider->ftp_retired) { + atomic_add_64(&provider->ftp_proc->ftpc_acount, -1); + ASSERT(provider->ftp_proc->ftpc_acount < + provider->ftp_proc->ftpc_rcount); + } + + fasttrap_proc_release(provider->ftp_proc); + + kmem_free(provider, sizeof (fasttrap_provider_t)); + + /* + * Decrement p_dtrace_probes on the process whose provider we're + * freeing. We don't have to worry about clobbering somone else's + * modifications to it because we have locked the bucket that + * corresponds to this process's hash chain in the provider hash + * table. Don't sweat it if we can't find the process. + */ + mutex_enter(&pidlock); + if ((p = prfind(pid)) == NULL) { + mutex_exit(&pidlock); + return; + } + + mutex_enter(&p->p_lock); + mutex_exit(&pidlock); + + p->p_dtrace_probes--; + mutex_exit(&p->p_lock); +} + +static void +fasttrap_provider_retire(pid_t pid, const char *name, int mprov) +{ + fasttrap_provider_t *fp; + fasttrap_bucket_t *bucket; + dtrace_provider_id_t provid; + + ASSERT(strlen(name) < sizeof (fp->ftp_name)); + + bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)]; + mutex_enter(&bucket->ftb_mtx); + + for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) { + if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 && + !fp->ftp_retired) + break; + } + + if (fp == NULL) { + mutex_exit(&bucket->ftb_mtx); + return; + } + + mutex_enter(&fp->ftp_mtx); + ASSERT(!mprov || fp->ftp_mcount > 0); + if (mprov && --fp->ftp_mcount != 0) { + mutex_exit(&fp->ftp_mtx); + mutex_exit(&bucket->ftb_mtx); + return; + } + + /* + * Mark the provider to be removed in our post-processing step, mark it + * retired, and drop the active count on its proc. Marking it indicates + * that we should try to remove it; setting the retired flag indicates + * that we're done with this provider; dropping the active the proc + * releases our hold, and when this reaches zero (as it will during + * exit or exec) the proc and associated providers become defunct. + * + * We obviously need to take the bucket lock before the provider lock + * to perform the lookup, but we need to drop the provider lock + * before calling into the DTrace framework since we acquire the + * provider lock in callbacks invoked from the DTrace framework. The + * bucket lock therefore protects the integrity of the provider hash + * table. + */ + atomic_add_64(&fp->ftp_proc->ftpc_acount, -1); + ASSERT(fp->ftp_proc->ftpc_acount < fp->ftp_proc->ftpc_rcount); + + fp->ftp_retired = 1; + fp->ftp_marked = 1; + provid = fp->ftp_provid; + mutex_exit(&fp->ftp_mtx); + + /* + * We don't have to worry about invalidating the same provider twice + * since fasttrap_provider_lookup() will ignore provider that have + * been marked as retired. + */ + dtrace_invalidate(provid); + + mutex_exit(&bucket->ftb_mtx); + + fasttrap_pid_cleanup(); +} + +static int +fasttrap_uint32_cmp(const void *ap, const void *bp) +{ + return (*(const uint32_t *)ap - *(const uint32_t *)bp); +} + +static int +fasttrap_uint64_cmp(const void *ap, const void *bp) +{ + return (*(const uint64_t *)ap - *(const uint64_t *)bp); +} + +static int +fasttrap_add_probe(fasttrap_probe_spec_t *pdata) +{ + fasttrap_provider_t *provider; + fasttrap_probe_t *pp; + fasttrap_tracepoint_t *tp; + char *name; + int i, aframes, whack; + + /* + * There needs to be at least one desired trace point. + */ + if (pdata->ftps_noffs == 0) + return (EINVAL); + + switch (pdata->ftps_type) { + case DTFTP_ENTRY: + name = "entry"; + aframes = FASTTRAP_ENTRY_AFRAMES; + break; + case DTFTP_RETURN: + name = "return"; + aframes = FASTTRAP_RETURN_AFRAMES; + break; + case DTFTP_OFFSETS: + name = NULL; + break; + default: + return (EINVAL); + } + + if ((provider = fasttrap_provider_lookup(pdata->ftps_pid, + FASTTRAP_PID_NAME, &pid_attr)) == NULL) + return (ESRCH); + + /* + * Increment this reference count to indicate that a consumer is + * actively adding a new probe associated with this provider. This + * prevents the provider from being deleted -- we'll need to check + * for pending deletions when we drop this reference count. + */ + provider->ftp_ccount++; + mutex_exit(&provider->ftp_mtx); + + /* + * Grab the creation lock to ensure consistency between calls to + * dtrace_probe_lookup() and dtrace_probe_create() in the face of + * other threads creating probes. We must drop the provider lock + * before taking this lock to avoid a three-way deadlock with the + * DTrace framework. + */ + mutex_enter(&provider->ftp_cmtx); + + if (name == NULL) { + for (i = 0; i < pdata->ftps_noffs; i++) { + char name_str[17]; + + (void) sprintf(name_str, "%llx", + (unsigned long long)pdata->ftps_offs[i]); + + if (dtrace_probe_lookup(provider->ftp_provid, + pdata->ftps_mod, pdata->ftps_func, name_str) != 0) + continue; + + atomic_add_32(&fasttrap_total, 1); + + if (fasttrap_total > fasttrap_max) { + atomic_add_32(&fasttrap_total, -1); + goto no_mem; + } + + pp = kmem_zalloc(sizeof (fasttrap_probe_t), KM_SLEEP); + + pp->ftp_prov = provider; + pp->ftp_faddr = pdata->ftps_pc; + pp->ftp_fsize = pdata->ftps_size; + pp->ftp_pid = pdata->ftps_pid; + pp->ftp_ntps = 1; + + tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), + KM_SLEEP); + + tp->ftt_proc = provider->ftp_proc; + tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc; + tp->ftt_pid = pdata->ftps_pid; + + pp->ftp_tps[0].fit_tp = tp; + pp->ftp_tps[0].fit_id.fti_probe = pp; + pp->ftp_tps[0].fit_id.fti_ptype = pdata->ftps_type; + + pp->ftp_id = dtrace_probe_create(provider->ftp_provid, + pdata->ftps_mod, pdata->ftps_func, name_str, + FASTTRAP_OFFSET_AFRAMES, pp); + } + + } else if (dtrace_probe_lookup(provider->ftp_provid, pdata->ftps_mod, + pdata->ftps_func, name) == 0) { + atomic_add_32(&fasttrap_total, pdata->ftps_noffs); + + if (fasttrap_total > fasttrap_max) { + atomic_add_32(&fasttrap_total, -pdata->ftps_noffs); + goto no_mem; + } + + /* + * Make sure all tracepoint program counter values are unique. + * We later assume that each probe has exactly one tracepoint + * for a given pc. + */ + qsort(pdata->ftps_offs, pdata->ftps_noffs, + sizeof (uint64_t), fasttrap_uint64_cmp); + for (i = 1; i < pdata->ftps_noffs; i++) { + if (pdata->ftps_offs[i] > pdata->ftps_offs[i - 1]) + continue; + + atomic_add_32(&fasttrap_total, -pdata->ftps_noffs); + goto no_mem; + } + + ASSERT(pdata->ftps_noffs > 0); + pp = kmem_zalloc(offsetof(fasttrap_probe_t, + ftp_tps[pdata->ftps_noffs]), KM_SLEEP); + + pp->ftp_prov = provider; + pp->ftp_faddr = pdata->ftps_pc; + pp->ftp_fsize = pdata->ftps_size; + pp->ftp_pid = pdata->ftps_pid; + pp->ftp_ntps = pdata->ftps_noffs; + + for (i = 0; i < pdata->ftps_noffs; i++) { + tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), + KM_SLEEP); + + tp->ftt_proc = provider->ftp_proc; + tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc; + tp->ftt_pid = pdata->ftps_pid; + + pp->ftp_tps[i].fit_tp = tp; + pp->ftp_tps[i].fit_id.fti_probe = pp; + pp->ftp_tps[i].fit_id.fti_ptype = pdata->ftps_type; + } + + pp->ftp_id = dtrace_probe_create(provider->ftp_provid, + pdata->ftps_mod, pdata->ftps_func, name, aframes, pp); + } + + mutex_exit(&provider->ftp_cmtx); + + /* + * We know that the provider is still valid since we incremented the + * creation reference count. If someone tried to clean up this provider + * while we were using it (e.g. because the process called exec(2) or + * exit(2)), take note of that and try to clean it up now. + */ + mutex_enter(&provider->ftp_mtx); + provider->ftp_ccount--; + whack = provider->ftp_retired; + mutex_exit(&provider->ftp_mtx); + + if (whack) + fasttrap_pid_cleanup(); + + return (0); + +no_mem: + /* + * If we've exhausted the allowable resources, we'll try to remove + * this provider to free some up. This is to cover the case where + * the user has accidentally created many more probes than was + * intended (e.g. pid123:::). + */ + mutex_exit(&provider->ftp_cmtx); + mutex_enter(&provider->ftp_mtx); + provider->ftp_ccount--; + provider->ftp_marked = 1; + mutex_exit(&provider->ftp_mtx); + + fasttrap_pid_cleanup(); + + return (ENOMEM); +} + +/*ARGSUSED*/ +static void * +fasttrap_meta_provide(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid) +{ + fasttrap_provider_t *provider; + + /* + * A 32-bit unsigned integer (like a pid for example) can be + * expressed in 10 or fewer decimal digits. Make sure that we'll + * have enough space for the provider name. + */ + if (strlen(dhpv->dthpv_provname) + 10 >= + sizeof (provider->ftp_name)) { + cmn_err(CE_WARN, "failed to instantiate provider %s: " + "name too long to accomodate pid", dhpv->dthpv_provname); + return (NULL); + } + + /* + * Don't let folks spoof the true pid provider. + */ + if (strcmp(dhpv->dthpv_provname, FASTTRAP_PID_NAME) == 0) { + cmn_err(CE_WARN, "failed to instantiate provider %s: " + "%s is an invalid name", dhpv->dthpv_provname, + FASTTRAP_PID_NAME); + return (NULL); + } + + /* + * The highest stability class that fasttrap supports is ISA; cap + * the stability of the new provider accordingly. + */ + if (dhpv->dthpv_pattr.dtpa_provider.dtat_class > DTRACE_CLASS_ISA) + dhpv->dthpv_pattr.dtpa_provider.dtat_class = DTRACE_CLASS_ISA; + if (dhpv->dthpv_pattr.dtpa_mod.dtat_class > DTRACE_CLASS_ISA) + dhpv->dthpv_pattr.dtpa_mod.dtat_class = DTRACE_CLASS_ISA; + if (dhpv->dthpv_pattr.dtpa_func.dtat_class > DTRACE_CLASS_ISA) + dhpv->dthpv_pattr.dtpa_func.dtat_class = DTRACE_CLASS_ISA; + if (dhpv->dthpv_pattr.dtpa_name.dtat_class > DTRACE_CLASS_ISA) + dhpv->dthpv_pattr.dtpa_name.dtat_class = DTRACE_CLASS_ISA; + if (dhpv->dthpv_pattr.dtpa_args.dtat_class > DTRACE_CLASS_ISA) + dhpv->dthpv_pattr.dtpa_args.dtat_class = DTRACE_CLASS_ISA; + + if ((provider = fasttrap_provider_lookup(pid, dhpv->dthpv_provname, + &dhpv->dthpv_pattr)) == NULL) { + cmn_err(CE_WARN, "failed to instantiate provider %s for " + "process %u", dhpv->dthpv_provname, (uint_t)pid); + return (NULL); + } + + /* + * Up the meta provider count so this provider isn't removed until + * the meta provider has been told to remove it. + */ + provider->ftp_mcount++; + + mutex_exit(&provider->ftp_mtx); + + return (provider); +} + +/*ARGSUSED*/ +static void +fasttrap_meta_create_probe(void *arg, void *parg, + dtrace_helper_probedesc_t *dhpb) +{ + fasttrap_provider_t *provider = parg; + fasttrap_probe_t *pp; + fasttrap_tracepoint_t *tp; + int i, j; + uint32_t ntps; + + /* + * Since the meta provider count is non-zero we don't have to worry + * about this provider disappearing. + */ + ASSERT(provider->ftp_mcount > 0); + + /* + * The offsets must be unique. + */ + qsort(dhpb->dthpb_offs, dhpb->dthpb_noffs, sizeof (uint32_t), + fasttrap_uint32_cmp); + for (i = 1; i < dhpb->dthpb_noffs; i++) { + if (dhpb->dthpb_base + dhpb->dthpb_offs[i] <= + dhpb->dthpb_base + dhpb->dthpb_offs[i - 1]) + return; + } + + qsort(dhpb->dthpb_enoffs, dhpb->dthpb_nenoffs, sizeof (uint32_t), + fasttrap_uint32_cmp); + for (i = 1; i < dhpb->dthpb_nenoffs; i++) { + if (dhpb->dthpb_base + dhpb->dthpb_enoffs[i] <= + dhpb->dthpb_base + dhpb->dthpb_enoffs[i - 1]) + return; + } + + /* + * Grab the creation lock to ensure consistency between calls to + * dtrace_probe_lookup() and dtrace_probe_create() in the face of + * other threads creating probes. + */ + mutex_enter(&provider->ftp_cmtx); + + if (dtrace_probe_lookup(provider->ftp_provid, dhpb->dthpb_mod, + dhpb->dthpb_func, dhpb->dthpb_name) != 0) { + mutex_exit(&provider->ftp_cmtx); + return; + } + + ntps = dhpb->dthpb_noffs + dhpb->dthpb_nenoffs; + ASSERT(ntps > 0); + + atomic_add_32(&fasttrap_total, ntps); + + if (fasttrap_total > fasttrap_max) { + atomic_add_32(&fasttrap_total, -ntps); + mutex_exit(&provider->ftp_cmtx); + return; + } + + pp = kmem_zalloc(offsetof(fasttrap_probe_t, ftp_tps[ntps]), KM_SLEEP); + + pp->ftp_prov = provider; + pp->ftp_pid = provider->ftp_pid; + pp->ftp_ntps = ntps; + pp->ftp_nargs = dhpb->dthpb_xargc; + pp->ftp_xtypes = dhpb->dthpb_xtypes; + pp->ftp_ntypes = dhpb->dthpb_ntypes; + + /* + * First create a tracepoint for each actual point of interest. + */ + for (i = 0; i < dhpb->dthpb_noffs; i++) { + tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP); + + tp->ftt_proc = provider->ftp_proc; + tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_offs[i]; + tp->ftt_pid = provider->ftp_pid; + + pp->ftp_tps[i].fit_tp = tp; + pp->ftp_tps[i].fit_id.fti_probe = pp; +#ifdef __sparc + pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_POST_OFFSETS; +#else + pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_OFFSETS; +#endif + } + + /* + * Then create a tracepoint for each is-enabled point. + */ + for (j = 0; i < ntps; i++, j++) { + tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP); + + tp->ftt_proc = provider->ftp_proc; + tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_enoffs[j]; + tp->ftt_pid = provider->ftp_pid; + + pp->ftp_tps[i].fit_tp = tp; + pp->ftp_tps[i].fit_id.fti_probe = pp; + pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_IS_ENABLED; + } + + /* + * If the arguments are shuffled around we set the argument remapping + * table. Later, when the probe fires, we only remap the arguments + * if the table is non-NULL. + */ + for (i = 0; i < dhpb->dthpb_xargc; i++) { + if (dhpb->dthpb_args[i] != i) { + pp->ftp_argmap = dhpb->dthpb_args; + break; + } + } + + /* + * The probe is fully constructed -- register it with DTrace. + */ + pp->ftp_id = dtrace_probe_create(provider->ftp_provid, dhpb->dthpb_mod, + dhpb->dthpb_func, dhpb->dthpb_name, FASTTRAP_OFFSET_AFRAMES, pp); + + mutex_exit(&provider->ftp_cmtx); +} + +/*ARGSUSED*/ +static void +fasttrap_meta_remove(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid) +{ + /* + * Clean up the USDT provider. There may be active consumers of the + * provider busy adding probes, no damage will actually befall the + * provider until that count has dropped to zero. This just puts + * the provider on death row. + */ + fasttrap_provider_retire(pid, dhpv->dthpv_provname, 1); +} + +static dtrace_mops_t fasttrap_mops = { + fasttrap_meta_create_probe, + fasttrap_meta_provide, + fasttrap_meta_remove +}; + +/*ARGSUSED*/ +static int +fasttrap_open(dev_t *devp, int flag, int otyp, cred_t *cred_p) +{ + return (0); +} + +/*ARGSUSED*/ +static int +fasttrap_ioctl(dev_t dev, int cmd, intptr_t arg, int md, cred_t *cr, int *rv) +{ + if (!dtrace_attached()) + return (EAGAIN); + + if (cmd == FASTTRAPIOC_MAKEPROBE) { + fasttrap_probe_spec_t *uprobe = (void *)arg; + fasttrap_probe_spec_t *probe; + uint64_t noffs; + size_t size; + int ret; + char *c; + + if (copyin(&uprobe->ftps_noffs, &noffs, + sizeof (uprobe->ftps_noffs))) + return (EFAULT); + + /* + * Probes must have at least one tracepoint. + */ + if (noffs == 0) + return (EINVAL); + + size = sizeof (fasttrap_probe_spec_t) + + sizeof (probe->ftps_offs[0]) * (noffs - 1); + + if (size > 1024 * 1024) + return (ENOMEM); + + probe = kmem_alloc(size, KM_SLEEP); + + if (copyin(uprobe, probe, size) != 0 || + probe->ftps_noffs != noffs) { + kmem_free(probe, size); + return (EFAULT); + } + + /* + * Verify that the function and module strings contain no + * funny characters. + */ + for (c = &probe->ftps_func[0]; *c != '\0'; c++) { + if (*c < 0x20 || 0x7f <= *c) { + ret = EINVAL; + goto err; + } + } + + for (c = &probe->ftps_mod[0]; *c != '\0'; c++) { + if (*c < 0x20 || 0x7f <= *c) { + ret = EINVAL; + goto err; + } + } + + if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) { + proc_t *p; + pid_t pid = probe->ftps_pid; + + mutex_enter(&pidlock); + /* + * Report an error if the process doesn't exist + * or is actively being birthed. + */ + if ((p = prfind(pid)) == NULL || p->p_stat == SIDL) { + mutex_exit(&pidlock); + return (ESRCH); + } + mutex_enter(&p->p_lock); + mutex_exit(&pidlock); + + if ((ret = priv_proc_cred_perm(cr, p, NULL, + VREAD | VWRITE)) != 0) { + mutex_exit(&p->p_lock); + return (ret); + } + + mutex_exit(&p->p_lock); + } + + ret = fasttrap_add_probe(probe); +err: + kmem_free(probe, size); + + return (ret); + + } else if (cmd == FASTTRAPIOC_GETINSTR) { + fasttrap_instr_query_t instr; + fasttrap_tracepoint_t *tp; + uint_t index; + int ret; + + if (copyin((void *)arg, &instr, sizeof (instr)) != 0) + return (EFAULT); + + if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) { + proc_t *p; + pid_t pid = instr.ftiq_pid; + + mutex_enter(&pidlock); + /* + * Report an error if the process doesn't exist + * or is actively being birthed. + */ + if ((p = prfind(pid)) == NULL || p->p_stat == SIDL) { + mutex_exit(&pidlock); + return (ESRCH); + } + mutex_enter(&p->p_lock); + mutex_exit(&pidlock); + + if ((ret = priv_proc_cred_perm(cr, p, NULL, + VREAD)) != 0) { + mutex_exit(&p->p_lock); + return (ret); + } + + mutex_exit(&p->p_lock); + } + + index = FASTTRAP_TPOINTS_INDEX(instr.ftiq_pid, instr.ftiq_pc); + + mutex_enter(&fasttrap_tpoints.fth_table[index].ftb_mtx); + tp = fasttrap_tpoints.fth_table[index].ftb_data; + while (tp != NULL) { + if (instr.ftiq_pid == tp->ftt_pid && + instr.ftiq_pc == tp->ftt_pc && + tp->ftt_proc->ftpc_acount != 0) + break; + + tp = tp->ftt_next; + } + + if (tp == NULL) { + mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx); + return (ENOENT); + } + + bcopy(&tp->ftt_instr, &instr.ftiq_instr, + sizeof (instr.ftiq_instr)); + mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx); + + if (copyout(&instr, (void *)arg, sizeof (instr)) != 0) + return (EFAULT); + + return (0); + } + + return (EINVAL); +} + +static struct cb_ops fasttrap_cb_ops = { + fasttrap_open, /* open */ + nodev, /* close */ + nulldev, /* strategy */ + nulldev, /* print */ + nodev, /* dump */ + nodev, /* read */ + nodev, /* write */ + fasttrap_ioctl, /* ioctl */ + nodev, /* devmap */ + nodev, /* mmap */ + nodev, /* segmap */ + nochpoll, /* poll */ + ddi_prop_op, /* cb_prop_op */ + 0, /* streamtab */ + D_NEW | D_MP /* Driver compatibility flag */ +}; + +/*ARGSUSED*/ +static int +fasttrap_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result) +{ + int error; + + switch (infocmd) { + case DDI_INFO_DEVT2DEVINFO: + *result = (void *)fasttrap_devi; + error = DDI_SUCCESS; + break; + case DDI_INFO_DEVT2INSTANCE: + *result = (void *)0; + error = DDI_SUCCESS; + break; + default: + error = DDI_FAILURE; + } + return (error); +} + +static int +fasttrap_attach(dev_info_t *devi, ddi_attach_cmd_t cmd) +{ + ulong_t nent; + + switch (cmd) { + case DDI_ATTACH: + break; + case DDI_RESUME: + return (DDI_SUCCESS); + default: + return (DDI_FAILURE); + } + + if (ddi_create_minor_node(devi, "fasttrap", S_IFCHR, 0, + DDI_PSEUDO, NULL) == DDI_FAILURE) { + ddi_remove_minor_node(devi, NULL); + return (DDI_FAILURE); + } + + ddi_report_dev(devi); + fasttrap_devi = devi; + + /* + * Install our hooks into fork(2), exec(2), and exit(2). + */ + dtrace_fasttrap_fork_ptr = &fasttrap_fork; + dtrace_fasttrap_exit_ptr = &fasttrap_exec_exit; + dtrace_fasttrap_exec_ptr = &fasttrap_exec_exit; + + fasttrap_max = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS, + "fasttrap-max-probes", FASTTRAP_MAX_DEFAULT); + fasttrap_total = 0; + + /* + * Conjure up the tracepoints hashtable... + */ + nent = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS, + "fasttrap-hash-size", FASTTRAP_TPOINTS_DEFAULT_SIZE); + + if (nent == 0 || nent > 0x1000000) + nent = FASTTRAP_TPOINTS_DEFAULT_SIZE; + + if ((nent & (nent - 1)) == 0) + fasttrap_tpoints.fth_nent = nent; + else + fasttrap_tpoints.fth_nent = 1 << fasttrap_highbit(nent); + ASSERT(fasttrap_tpoints.fth_nent > 0); + fasttrap_tpoints.fth_mask = fasttrap_tpoints.fth_nent - 1; + fasttrap_tpoints.fth_table = kmem_zalloc(fasttrap_tpoints.fth_nent * + sizeof (fasttrap_bucket_t), KM_SLEEP); + + /* + * ... and the providers hash table... + */ + nent = FASTTRAP_PROVIDERS_DEFAULT_SIZE; + if ((nent & (nent - 1)) == 0) + fasttrap_provs.fth_nent = nent; + else + fasttrap_provs.fth_nent = 1 << fasttrap_highbit(nent); + ASSERT(fasttrap_provs.fth_nent > 0); + fasttrap_provs.fth_mask = fasttrap_provs.fth_nent - 1; + fasttrap_provs.fth_table = kmem_zalloc(fasttrap_provs.fth_nent * + sizeof (fasttrap_bucket_t), KM_SLEEP); + + /* + * ... and the procs hash table. + */ + nent = FASTTRAP_PROCS_DEFAULT_SIZE; + if ((nent & (nent - 1)) == 0) + fasttrap_procs.fth_nent = nent; + else + fasttrap_procs.fth_nent = 1 << fasttrap_highbit(nent); + ASSERT(fasttrap_procs.fth_nent > 0); + fasttrap_procs.fth_mask = fasttrap_procs.fth_nent - 1; + fasttrap_procs.fth_table = kmem_zalloc(fasttrap_procs.fth_nent * + sizeof (fasttrap_bucket_t), KM_SLEEP); + + (void) dtrace_meta_register("fasttrap", &fasttrap_mops, NULL, + &fasttrap_meta_id); + + return (DDI_SUCCESS); +} + +static int +fasttrap_detach(dev_info_t *devi, ddi_detach_cmd_t cmd) +{ + int i, fail = 0; + timeout_id_t tmp; + + switch (cmd) { + case DDI_DETACH: + break; + case DDI_SUSPEND: + return (DDI_SUCCESS); + default: + return (DDI_FAILURE); + } + + /* + * Unregister the meta-provider to make sure no new fasttrap- + * managed providers come along while we're trying to close up + * shop. If we fail to detach, we'll need to re-register as a + * meta-provider. We can fail to unregister as a meta-provider + * if providers we manage still exist. + */ + if (fasttrap_meta_id != DTRACE_METAPROVNONE && + dtrace_meta_unregister(fasttrap_meta_id) != 0) + return (DDI_FAILURE); + + /* + * Prevent any new timeouts from running by setting fasttrap_timeout + * to a non-zero value, and wait for the current timeout to complete. + */ + mutex_enter(&fasttrap_cleanup_mtx); + fasttrap_cleanup_work = 0; + + while (fasttrap_timeout != (timeout_id_t)1) { + tmp = fasttrap_timeout; + fasttrap_timeout = (timeout_id_t)1; + + if (tmp != 0) { + mutex_exit(&fasttrap_cleanup_mtx); + (void) untimeout(tmp); + mutex_enter(&fasttrap_cleanup_mtx); + } + } + + fasttrap_cleanup_work = 0; + mutex_exit(&fasttrap_cleanup_mtx); + + /* + * Iterate over all of our providers. If there's still a process + * that corresponds to that pid, fail to detach. + */ + for (i = 0; i < fasttrap_provs.fth_nent; i++) { + fasttrap_provider_t **fpp, *fp; + fasttrap_bucket_t *bucket = &fasttrap_provs.fth_table[i]; + + mutex_enter(&bucket->ftb_mtx); + fpp = (fasttrap_provider_t **)&bucket->ftb_data; + while ((fp = *fpp) != NULL) { + /* + * Acquire and release the lock as a simple way of + * waiting for any other consumer to finish with + * this provider. A thread must first acquire the + * bucket lock so there's no chance of another thread + * blocking on the provider's lock. + */ + mutex_enter(&fp->ftp_mtx); + mutex_exit(&fp->ftp_mtx); + + if (dtrace_unregister(fp->ftp_provid) != 0) { + fail = 1; + fpp = &fp->ftp_next; + } else { + *fpp = fp->ftp_next; + fasttrap_provider_free(fp); + } + } + + mutex_exit(&bucket->ftb_mtx); + } + + if (fail) { + uint_t work; + /* + * If we're failing to detach, we need to unblock timeouts + * and start a new timeout if any work has accumulated while + * we've been unsuccessfully trying to detach. + */ + mutex_enter(&fasttrap_cleanup_mtx); + fasttrap_timeout = 0; + work = fasttrap_cleanup_work; + mutex_exit(&fasttrap_cleanup_mtx); + + if (work) + fasttrap_pid_cleanup(); + + (void) dtrace_meta_register("fasttrap", &fasttrap_mops, NULL, + &fasttrap_meta_id); + + return (DDI_FAILURE); + } + +#ifdef DEBUG + mutex_enter(&fasttrap_count_mtx); + ASSERT(fasttrap_pid_count == 0); + mutex_exit(&fasttrap_count_mtx); +#endif + + kmem_free(fasttrap_tpoints.fth_table, + fasttrap_tpoints.fth_nent * sizeof (fasttrap_bucket_t)); + fasttrap_tpoints.fth_nent = 0; + + kmem_free(fasttrap_provs.fth_table, + fasttrap_provs.fth_nent * sizeof (fasttrap_bucket_t)); + fasttrap_provs.fth_nent = 0; + + kmem_free(fasttrap_procs.fth_table, + fasttrap_procs.fth_nent * sizeof (fasttrap_bucket_t)); + fasttrap_procs.fth_nent = 0; + + /* + * We know there are no tracepoints in any process anywhere in + * the system so there is no process which has its p_dtrace_count + * greater than zero, therefore we know that no thread can actively + * be executing code in fasttrap_fork(). Similarly for p_dtrace_probes + * and fasttrap_exec() and fasttrap_exit(). + */ + ASSERT(dtrace_fasttrap_fork_ptr == &fasttrap_fork); + dtrace_fasttrap_fork_ptr = NULL; + + ASSERT(dtrace_fasttrap_exec_ptr == &fasttrap_exec_exit); + dtrace_fasttrap_exec_ptr = NULL; + + ASSERT(dtrace_fasttrap_exit_ptr == &fasttrap_exec_exit); + dtrace_fasttrap_exit_ptr = NULL; + + ddi_remove_minor_node(devi, NULL); + + return (DDI_SUCCESS); +} + +static struct dev_ops fasttrap_ops = { + DEVO_REV, /* devo_rev */ + 0, /* refcnt */ + fasttrap_info, /* get_dev_info */ + nulldev, /* identify */ + nulldev, /* probe */ + fasttrap_attach, /* attach */ + fasttrap_detach, /* detach */ + nodev, /* reset */ + &fasttrap_cb_ops, /* driver operations */ + NULL, /* bus operations */ + nodev, /* dev power */ + ddi_quiesce_not_needed, /* quiesce */ +}; + +/* + * Module linkage information for the kernel. + */ +static struct modldrv modldrv = { + &mod_driverops, /* module type (this is a pseudo driver) */ + "Fasttrap Tracing", /* name of module */ + &fasttrap_ops, /* driver ops */ +}; + +static struct modlinkage modlinkage = { + MODREV_1, + (void *)&modldrv, + NULL +}; + +int +_init(void) +{ + return (mod_install(&modlinkage)); +} + +int +_info(struct modinfo *modinfop) +{ + return (mod_info(&modlinkage, modinfop)); +} + +int +_fini(void) +{ + return (mod_remove(&modlinkage)); +} |