X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/378393581903b274cb7a4d18e0d978071a6b592d..5ba3f43ea354af8ad55bea84372a2bc834d8757c:/osfmk/kern/sync_sema.c diff --git a/osfmk/kern/sync_sema.c b/osfmk/kern/sync_sema.c index dc22aaa4e..0a6f7b33d 100644 --- a/osfmk/kern/sync_sema.c +++ b/osfmk/kern/sync_sema.c @@ -1,23 +1,29 @@ /* - * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2000-2009 Apple Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * - * The contents of this file constitute Original Code as defined in and - * are subject to the Apple Public Source License Version 1.1 (the - * "License"). You may not use this file except in compliance with the - * License. Please obtain a copy of the License at - * http://www.apple.com/publicsource and read it before using this file. + * This file contains Original Code and/or Modifications of Original Code + * as defined in and that are subject to the Apple Public Source License + * Version 2.0 (the 'License'). You may not use this file except in + * compliance with the License. The rights granted to you under the License + * may not be used to create, or enable the creation or redistribution of, + * unlawful or unlicensed copies of an Apple operating system, or to + * circumvent, violate, or enable the circumvention or violation of, any + * terms of an Apple operating system software license agreement. * - * This Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the - * License for the specific language governing rights and limitations - * under the License. + * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * Please see the License for the specific language governing rights and + * limitations under the License. * - * @APPLE_LICENSE_HEADER_END@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ @@ -48,15 +54,17 @@ #include #include #include -#include +#include #include #include +#include + static unsigned int semaphore_event; -#define SEMAPHORE_EVENT ((event64_t)&semaphore_event) +#define SEMAPHORE_EVENT CAST_EVENT64_T(&semaphore_event) zone_t semaphore_zone; -unsigned int semaphore_max = SEMAPHORE_MAX; +unsigned int semaphore_max; /* Forward declarations */ @@ -87,6 +95,8 @@ semaphore_timedwait_signal_trap_internal( clock_res_t nsec, void (*caller_cont)(kern_return_t)); +kern_return_t +semaphore_signal_internal_trap(mach_port_name_t sema_name); kern_return_t semaphore_signal_internal( @@ -101,13 +111,27 @@ semaphore_convert_wait_result( void semaphore_wait_continue(void); -kern_return_t +static kern_return_t semaphore_wait_internal( semaphore_t wait_semaphore, semaphore_t signal_semaphore, - mach_timespec_t *wait_timep, + uint64_t deadline, + int option, void (*caller_cont)(kern_return_t)); +static __inline__ uint64_t +semaphore_deadline( + unsigned int sec, + clock_res_t nsec) +{ + uint64_t abstime; + + nanoseconds_to_absolutetime((uint64_t)sec * NSEC_PER_SEC + nsec, &abstime); + clock_absolutetime_interval_to_deadline(abstime, &abstime); + + return (abstime); +} + /* * ROUTINE: semaphore_init [private] * @@ -121,6 +145,7 @@ semaphore_init(void) semaphore_max * sizeof(struct semaphore), sizeof(struct semaphore), "semaphores"); + zone_change(semaphore_zone, Z_NOENCRYPT, TRUE); } /* @@ -137,50 +162,40 @@ semaphore_create( int value) { semaphore_t s = SEMAPHORE_NULL; + kern_return_t kret; - - if (task == TASK_NULL || value < 0 || policy > SYNC_POLICY_MAX) { - *new_semaphore = SEMAPHORE_NULL; + *new_semaphore = SEMAPHORE_NULL; + if (task == TASK_NULL || value < 0 || policy > SYNC_POLICY_MAX) return KERN_INVALID_ARGUMENT; - } s = (semaphore_t) zalloc (semaphore_zone); - if (s == SEMAPHORE_NULL) { - *new_semaphore = SEMAPHORE_NULL; + if (s == SEMAPHORE_NULL) return KERN_RESOURCE_SHORTAGE; - } - wait_queue_init(&s->wait_queue, policy); /* also inits lock */ - s->count = value; - s->ref_count = 1; + kret = waitq_init(&s->waitq, policy | SYNC_POLICY_DISABLE_IRQ); /* also inits lock */ + if (kret != KERN_SUCCESS) { + zfree(semaphore_zone, s); + return kret; + } /* - * Create and initialize the semaphore port + * Initialize the semaphore values. */ - s->port = ipc_port_alloc_kernel(); - if (s->port == IP_NULL) { - /* This will deallocate the semaphore */ - semaphore_dereference(s); - *new_semaphore = SEMAPHORE_NULL; - return KERN_RESOURCE_SHORTAGE; - } - - ipc_kobject_set (s->port, (ipc_kobject_t) s, IKOT_SEMAPHORE); + s->port = IP_NULL; + s->ref_count = 1; + s->count = value; + s->active = TRUE; + s->owner = task; /* * Associate the new semaphore with the task by adding * the new semaphore to the task's semaphore list. - * - * Associate the task with the new semaphore by having the - * semaphores task pointer point to the owning task's structure. */ task_lock(task); enqueue_head(&task->semaphore_list, (queue_entry_t) s); task->semaphores_owned++; - s->owner = task; - s->active = TRUE; task_unlock(task); *new_semaphore = s; @@ -189,42 +204,30 @@ semaphore_create( } /* - * Routine: semaphore_destroy + * Routine: semaphore_destroy_internal * - * Destroys a semaphore. This call will only succeed if the - * specified task is the SAME task name specified at the semaphore's - * creation. + * Disassociate a semaphore from its owning task, mark it inactive, + * and set any waiting threads running with THREAD_RESTART. * - * All threads currently blocked on the semaphore are awoken. These - * threads will return with the KERN_TERMINATED error. + * Conditions: + * task is locked + * semaphore is locked + * semaphore is owned by the specified task + * Returns: + * with semaphore unlocked */ -kern_return_t -semaphore_destroy( +static void +semaphore_destroy_internal( task_t task, semaphore_t semaphore) { - int old_count; - spl_t spl_level; - - - if (task == TASK_NULL || semaphore == SEMAPHORE_NULL) - return KERN_INVALID_ARGUMENT; + int old_count; - /* - * Disown semaphore - */ - task_lock(task); - if (semaphore->owner != task) { - task_unlock(task); - return KERN_INVALID_ARGUMENT; - } - remqueue(&task->semaphore_list, (queue_entry_t) semaphore); + /* unlink semaphore from owning task */ + assert(semaphore->owner == task); + remqueue((queue_entry_t) semaphore); semaphore->owner = TASK_NULL; task->semaphores_owned--; - task_unlock(task); - - spl_level = splsched(); - semaphore_lock(semaphore); /* * Deactivate semaphore @@ -239,26 +242,99 @@ semaphore_destroy( semaphore->count = 0; if (old_count < 0) { - wait_queue_wakeup64_all_locked(&semaphore->wait_queue, - SEMAPHORE_EVENT, - THREAD_RESTART, - TRUE); /* unlock? */ + waitq_wakeup64_all_locked(&semaphore->waitq, + SEMAPHORE_EVENT, + THREAD_RESTART, NULL, + WAITQ_ALL_PRIORITIES, + WAITQ_UNLOCK); + /* waitq/semaphore is unlocked */ } else { semaphore_unlock(semaphore); } +} + +/* + * Routine: semaphore_destroy + * + * Destroys a semaphore and consume the caller's reference on the + * semaphore. + */ +kern_return_t +semaphore_destroy( + task_t task, + semaphore_t semaphore) +{ + spl_t spl_level; + + if (semaphore == SEMAPHORE_NULL) + return KERN_INVALID_ARGUMENT; + + if (task == TASK_NULL) { + semaphore_dereference(semaphore); + return KERN_INVALID_ARGUMENT; + } + + task_lock(task); + spl_level = splsched(); + semaphore_lock(semaphore); + + if (semaphore->owner != task) { + semaphore_unlock(semaphore); + splx(spl_level); + task_unlock(task); + return KERN_INVALID_ARGUMENT; + } + + semaphore_destroy_internal(task, semaphore); + /* semaphore unlocked */ + splx(spl_level); + task_unlock(task); - /* - * Deallocate - * - * Drop the semaphore reference, which in turn deallocates the - * semaphore structure if the reference count goes to zero. - */ - ipc_port_dealloc_kernel(semaphore->port); semaphore_dereference(semaphore); return KERN_SUCCESS; } +/* + * Routine: semaphore_destroy_all + * + * Destroy all the semaphores associated with a given task. + */ +#define SEMASPERSPL 20 /* max number of semaphores to destroy per spl hold */ + +void +semaphore_destroy_all( + task_t task) +{ + uint32_t count; + spl_t spl_level; + + count = 0; + task_lock(task); + while (!queue_empty(&task->semaphore_list)) { + semaphore_t semaphore; + + semaphore = (semaphore_t) queue_first(&task->semaphore_list); + + if (count == 0) + spl_level = splsched(); + semaphore_lock(semaphore); + + semaphore_destroy_internal(task, semaphore); + /* semaphore unlocked */ + + /* throttle number of semaphores per interrupt disablement */ + if (++count == SEMASPERSPL) { + count = 0; + splx(spl_level); + } + } + if (count != 0) + splx(spl_level); + + task_unlock(task); +} + /* * Routine: semaphore_signal_internal * @@ -286,15 +362,16 @@ semaphore_signal_internal( if (thread != THREAD_NULL) { if (semaphore->count < 0) { - kr = wait_queue_wakeup64_thread_locked( - &semaphore->wait_queue, + kr = waitq_wakeup64_thread_locked( + &semaphore->waitq, SEMAPHORE_EVENT, thread, THREAD_AWAKENED, - TRUE); /* unlock? */ + WAITQ_UNLOCK); + /* waitq/semaphore is unlocked */ } else { - semaphore_unlock(semaphore); kr = KERN_NOT_WAITING; + semaphore_unlock(semaphore); } splx(spl_level); return kr; @@ -303,34 +380,40 @@ semaphore_signal_internal( if (options & SEMAPHORE_SIGNAL_ALL) { int old_count = semaphore->count; + kr = KERN_NOT_WAITING; if (old_count < 0) { semaphore->count = 0; /* always reset */ - kr = wait_queue_wakeup64_all_locked( - &semaphore->wait_queue, + kr = waitq_wakeup64_all_locked( + &semaphore->waitq, SEMAPHORE_EVENT, - THREAD_AWAKENED, - TRUE); /* unlock? */ + THREAD_AWAKENED, NULL, + WAITQ_ALL_PRIORITIES, + WAITQ_UNLOCK); + /* waitq / semaphore is unlocked */ } else { if (options & SEMAPHORE_SIGNAL_PREPOST) semaphore->count++; - semaphore_unlock(semaphore); kr = KERN_SUCCESS; + semaphore_unlock(semaphore); } splx(spl_level); return kr; } if (semaphore->count < 0) { - if (wait_queue_wakeup64_one_locked( - &semaphore->wait_queue, + kr = waitq_wakeup64_one_locked( + &semaphore->waitq, SEMAPHORE_EVENT, - THREAD_AWAKENED, - FALSE) == KERN_SUCCESS) { + THREAD_AWAKENED, NULL, + WAITQ_ALL_PRIORITIES, + WAITQ_KEEP_LOCKED); + if (kr == KERN_SUCCESS) { semaphore_unlock(semaphore); splx(spl_level); return KERN_SUCCESS; - } else + } else { semaphore->count = 0; /* all waiters gone */ + } } if (options & SEMAPHORE_SIGNAL_PREPOST) { @@ -446,6 +529,13 @@ semaphore_signal_trap( struct semaphore_signal_trap_args *args) { mach_port_name_t sema_name = args->signal_name; + + return (semaphore_signal_internal_trap(sema_name)); +} + +kern_return_t +semaphore_signal_internal_trap(mach_port_name_t sema_name) +{ semaphore_t semaphore; kern_return_t kr; @@ -571,14 +661,14 @@ semaphore_wait_continue(void) * The reference * A reference is held on the signal semaphore. */ -kern_return_t +static kern_return_t semaphore_wait_internal( semaphore_t wait_semaphore, semaphore_t signal_semaphore, - mach_timespec_t *wait_timep, + uint64_t deadline, + int option, void (*caller_cont)(kern_return_t)) { - boolean_t nonblocking; int wait_result; spl_t spl_level; kern_return_t kr = KERN_ALREADY_WAITING; @@ -586,44 +676,26 @@ semaphore_wait_internal( spl_level = splsched(); semaphore_lock(wait_semaphore); - /* - * Decide if we really have to wait. - */ - nonblocking = (wait_timep != (mach_timespec_t *)0) ? - (wait_timep->tv_sec == 0 && wait_timep->tv_nsec == 0) : - FALSE; - if (!wait_semaphore->active) { kr = KERN_TERMINATED; } else if (wait_semaphore->count > 0) { wait_semaphore->count--; kr = KERN_SUCCESS; - } else if (nonblocking) { + } else if (option & SEMAPHORE_TIMEOUT_NOBLOCK) { kr = KERN_OPERATION_TIMED_OUT; } else { - uint64_t abstime; thread_t self = current_thread(); wait_semaphore->count = -1; /* we don't keep an actual count */ - thread_lock(self); - - /* - * If it is a timed wait, calculate the wake up deadline. - */ - if (wait_timep != (mach_timespec_t *)0) { - nanoseconds_to_absolutetime((uint64_t)wait_timep->tv_sec * - NSEC_PER_SEC + wait_timep->tv_nsec, &abstime); - clock_absolutetime_interval_to_deadline(abstime, &abstime); - } - else - abstime = 0; - (void)wait_queue_assert_wait64_locked( - &wait_semaphore->wait_queue, + thread_set_pending_block_hint(self, kThreadWaitSemaphore); + (void)waitq_assert_wait64_locked( + &wait_semaphore->waitq, SEMAPHORE_EVENT, - THREAD_ABORTSAFE, abstime, + THREAD_ABORTSAFE, + TIMEOUT_URGENCY_USER_NORMAL, + deadline, TIMEOUT_NO_LEEWAY, self); - thread_unlock(self); } semaphore_unlock(wait_semaphore); splx(spl_level); @@ -714,8 +786,37 @@ semaphore_wait( return KERN_INVALID_ARGUMENT; return(semaphore_wait_internal(semaphore, - SEMAPHORE_NULL, - (mach_timespec_t *)0, + SEMAPHORE_NULL, + 0ULL, SEMAPHORE_OPTION_NONE, + (void (*)(kern_return_t))0)); +} + +kern_return_t +semaphore_wait_noblock( + semaphore_t semaphore) +{ + + if (semaphore == SEMAPHORE_NULL) + return KERN_INVALID_ARGUMENT; + + return(semaphore_wait_internal(semaphore, + SEMAPHORE_NULL, + 0ULL, SEMAPHORE_TIMEOUT_NOBLOCK, + (void (*)(kern_return_t))0)); +} + +kern_return_t +semaphore_wait_deadline( + semaphore_t semaphore, + uint64_t deadline) +{ + + if (semaphore == SEMAPHORE_NULL) + return KERN_INVALID_ARGUMENT; + + return(semaphore_wait_internal(semaphore, + SEMAPHORE_NULL, + deadline, SEMAPHORE_OPTION_NONE, (void (*)(kern_return_t))0)); } @@ -747,7 +848,7 @@ semaphore_wait_trap_internal( if (kr == KERN_SUCCESS) { kr = semaphore_wait_internal(semaphore, SEMAPHORE_NULL, - (mach_timespec_t *)0, + 0ULL, SEMAPHORE_OPTION_NONE, caller_cont); semaphore_dereference(semaphore); } @@ -766,16 +867,24 @@ kern_return_t semaphore_timedwait( semaphore_t semaphore, mach_timespec_t wait_time) -{ +{ + int option = SEMAPHORE_OPTION_NONE; + uint64_t deadline = 0; + if (semaphore == SEMAPHORE_NULL) return KERN_INVALID_ARGUMENT; if(BAD_MACH_TIMESPEC(&wait_time)) return KERN_INVALID_VALUE; + + if (wait_time.tv_sec == 0 && wait_time.tv_nsec == 0) + option = SEMAPHORE_TIMEOUT_NOBLOCK; + else + deadline = semaphore_deadline(wait_time.tv_sec, wait_time.tv_nsec); return (semaphore_wait_internal(semaphore, SEMAPHORE_NULL, - &wait_time, + deadline, option, (void(*)(kern_return_t))0)); } @@ -807,7 +916,6 @@ semaphore_timedwait_trap_internal( clock_res_t nsec, void (*caller_cont)(kern_return_t)) { - semaphore_t semaphore; mach_timespec_t wait_time; kern_return_t kr; @@ -819,9 +927,17 @@ semaphore_timedwait_trap_internal( kr = port_name_to_semaphore(name, &semaphore); if (kr == KERN_SUCCESS) { + int option = SEMAPHORE_OPTION_NONE; + uint64_t deadline = 0; + + if (sec == 0 && nsec == 0) + option = SEMAPHORE_TIMEOUT_NOBLOCK; + else + deadline = semaphore_deadline(sec, nsec); + kr = semaphore_wait_internal(semaphore, SEMAPHORE_NULL, - &wait_time, + deadline, option, caller_cont); semaphore_dereference(semaphore); } @@ -846,7 +962,7 @@ semaphore_wait_signal( return(semaphore_wait_internal(wait_semaphore, signal_semaphore, - (mach_timespec_t *)0, + 0ULL, SEMAPHORE_OPTION_NONE, (void(*)(kern_return_t))0)); } @@ -879,7 +995,7 @@ semaphore_wait_signal_trap_internal( if (kr == KERN_SUCCESS) { kr = semaphore_wait_internal(wait_semaphore, signal_semaphore, - (mach_timespec_t *)0, + 0ULL, SEMAPHORE_OPTION_NONE, caller_cont); semaphore_dereference(wait_semaphore); } @@ -904,15 +1020,23 @@ semaphore_timedwait_signal( semaphore_t signal_semaphore, mach_timespec_t wait_time) { + int option = SEMAPHORE_OPTION_NONE; + uint64_t deadline = 0; + if (wait_semaphore == SEMAPHORE_NULL) return KERN_INVALID_ARGUMENT; if(BAD_MACH_TIMESPEC(&wait_time)) return KERN_INVALID_VALUE; + + if (wait_time.tv_sec == 0 && wait_time.tv_nsec == 0) + option = SEMAPHORE_TIMEOUT_NOBLOCK; + else + deadline = semaphore_deadline(wait_time.tv_sec, wait_time.tv_nsec); return(semaphore_wait_internal(wait_semaphore, signal_semaphore, - &wait_time, + deadline, option, (void(*)(kern_return_t))0)); } @@ -951,9 +1075,17 @@ semaphore_timedwait_signal_trap_internal( if (kr == KERN_SUCCESS) { kr = port_name_to_semaphore(wait_name, &wait_semaphore); if (kr == KERN_SUCCESS) { + int option = SEMAPHORE_OPTION_NONE; + uint64_t deadline = 0; + + if (sec == 0 && nsec == 0) + option = SEMAPHORE_TIMEOUT_NOBLOCK; + else + deadline = semaphore_deadline(sec, nsec); + kr = semaphore_wait_internal(wait_semaphore, signal_semaphore, - &wait_time, + deadline, option, caller_cont); semaphore_dereference(wait_semaphore); } @@ -973,15 +1105,7 @@ void semaphore_reference( semaphore_t semaphore) { - spl_t spl_level; - - spl_level = splsched(); - semaphore_lock(semaphore); - - semaphore->ref_count++; - - semaphore_unlock(semaphore); - splx(spl_level); + (void)hw_atomic_add(&semaphore->ref_count, 1); } /* @@ -994,21 +1118,70 @@ void semaphore_dereference( semaphore_t semaphore) { - int ref_count; - spl_t spl_level; + uint32_t collisions; + spl_t spl_level; - if (semaphore != NULL) { - spl_level = splsched(); - semaphore_lock(semaphore); + if (semaphore == NULL) + return; - ref_count = --(semaphore->ref_count); + if (hw_atomic_sub(&semaphore->ref_count, 1) != 0) + return; - semaphore_unlock(semaphore); - splx(spl_level); + /* + * Last ref, clean up the port [if any] + * associated with the semaphore, destroy + * it (if still active) and then free + * the semaphore. + */ + ipc_port_t port = semaphore->port; + + if (IP_VALID(port)) { + assert(!port->ip_srights); + ipc_port_dealloc_kernel(port); + } - if (ref_count == 0) { - assert(wait_queue_empty(&semaphore->wait_queue)); - zfree(semaphore_zone, semaphore); - } + /* + * Lock the semaphore to lock in the owner task reference. + * Then continue to try to lock the task (inverse order). + */ + spl_level = splsched(); + semaphore_lock(semaphore); + for (collisions = 0; semaphore->active; collisions++) { + task_t task = semaphore->owner; + + assert(task != TASK_NULL); + + if (task_lock_try(task)) { + semaphore_destroy_internal(task, semaphore); + /* semaphore unlocked */ + splx(spl_level); + task_unlock(task); + goto out; + } + + /* failed to get out-of-order locks */ + semaphore_unlock(semaphore); + splx(spl_level); + mutex_pause(collisions); + spl_level = splsched(); + semaphore_lock(semaphore); } + semaphore_unlock(semaphore); + splx(spl_level); + + out: + zfree(semaphore_zone, semaphore); +} + +#define WAITQ_TO_SEMA(wq) ((semaphore_t) ((uintptr_t)(wq) - offsetof(struct semaphore, waitq))) +void +kdp_sema_find_owner(struct waitq * waitq, __assert_only event64_t event, thread_waitinfo_t * waitinfo) +{ + semaphore_t sem = WAITQ_TO_SEMA(waitq); + assert(event == SEMAPHORE_EVENT); + assert(kdp_is_in_zone(sem, "semaphores")); + + waitinfo->context = VM_KERNEL_UNSLIDE_OR_PERM(sem->port); + if (sem->owner) + waitinfo->owner = pid_from_task(sem->owner); }