X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/6601e61aa18bf4f09af135ff61fc7f4771d23b06..HEAD:/osfmk/kern/sync_sema.c diff --git a/osfmk/kern/sync_sema.c b/osfmk/kern/sync_sema.c index dc22aaa4e..dfa8d1153 100644 --- a/osfmk/kern/sync_sema.c +++ b/osfmk/kern/sync_sema.c @@ -1,27 +1,33 @@ /* - * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved. - * - * @APPLE_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 Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * Copyright (c) 2000-2020 Apple Inc. All rights reserved. + * + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ + * + * 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. + * + * 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. - * - * @APPLE_LICENSE_HEADER_END@ + * 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_OSREFERENCE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ - * + * */ /* * File: kern/sync_sema.c @@ -48,79 +54,83 @@ #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_DECLARE(semaphore_zone, "semaphores", sizeof(struct semaphore), ZC_NONE); -zone_t semaphore_zone; -unsigned int semaphore_max = SEMAPHORE_MAX; +os_refgrp_decl(static, sema_refgrp, "semaphore", NULL); /* Forward declarations */ -kern_return_t +kern_return_t semaphore_wait_trap_internal( - mach_port_name_t name, - void (*caller_cont)(kern_return_t)); + mach_port_name_t name, + void (*caller_cont)(kern_return_t)); -kern_return_t +kern_return_t semaphore_wait_signal_trap_internal( - mach_port_name_t wait_name, - mach_port_name_t signal_name, - void (*caller_cont)(kern_return_t)); + mach_port_name_t wait_name, + mach_port_name_t signal_name, + void (*caller_cont)(kern_return_t)); -kern_return_t +kern_return_t semaphore_timedwait_trap_internal( - mach_port_name_t name, - unsigned int sec, - clock_res_t nsec, - void (*caller_cont)(kern_return_t)); + mach_port_name_t name, + unsigned int sec, + clock_res_t nsec, + void (*caller_cont)(kern_return_t)); -kern_return_t +kern_return_t semaphore_timedwait_signal_trap_internal( - mach_port_name_t wait_name, - mach_port_name_t signal_name, - unsigned int sec, - clock_res_t nsec, - void (*caller_cont)(kern_return_t)); + mach_port_name_t wait_name, + mach_port_name_t signal_name, + unsigned int sec, + 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( - semaphore_t semaphore, - thread_t thread, - int options); + semaphore_t semaphore, + thread_t thread, + int options); kern_return_t semaphore_convert_wait_result( - int wait_result); + int wait_result); void -semaphore_wait_continue(void); +semaphore_wait_continue(void *arg __unused, wait_result_t wr); -kern_return_t +static kern_return_t semaphore_wait_internal( - semaphore_t wait_semaphore, - semaphore_t signal_semaphore, - mach_timespec_t *wait_timep, - void (*caller_cont)(kern_return_t)); - -/* - * ROUTINE: semaphore_init [private] - * - * Initialize the semaphore mechanisms. - * Right now, we only need to initialize the semaphore zone. - */ -void -semaphore_init(void) + semaphore_t wait_semaphore, + semaphore_t signal_semaphore, + uint64_t deadline, + int option, + void (*caller_cont)(kern_return_t)); + +static __inline__ uint64_t +semaphore_deadline( + unsigned int sec, + clock_res_t nsec) { - semaphore_zone = zinit(sizeof(struct semaphore), - semaphore_max * sizeof(struct semaphore), - sizeof(struct semaphore), - "semaphores"); + uint64_t abstime; + + nanoseconds_to_absolutetime((uint64_t)sec * NSEC_PER_SEC + nsec, &abstime); + clock_absolutetime_interval_to_deadline(abstime, &abstime); + + return abstime; } /* @@ -131,100 +141,85 @@ semaphore_init(void) */ kern_return_t semaphore_create( - task_t task, - semaphore_t *new_semaphore, - int policy, - int value) + task_t task, + semaphore_t *new_semaphore, + int policy, + int value) { - semaphore_t s = SEMAPHORE_NULL; - + 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 || policy < 0) { return KERN_INVALID_ARGUMENT; } - s = (semaphore_t) zalloc (semaphore_zone); + s = (semaphore_t) zalloc(semaphore_zone); if (s == SEMAPHORE_NULL) { - *new_semaphore = SEMAPHORE_NULL; - return KERN_RESOURCE_SHORTAGE; + 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; + os_ref_init(&s->ref_count, &sema_refgrp); + 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); + /* Check for race with task_terminate */ + if (!task->active) { + task_unlock(task); + zfree(semaphore_zone, s); + return KERN_INVALID_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; return KERN_SUCCESS; -} +} /* - * 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( - task_t task, - semaphore_t semaphore) +static void +semaphore_destroy_internal( + task_t task, + semaphore_t semaphore) { - int old_count; - spl_t spl_level; + int old_count; - - if (task == TASK_NULL || semaphore == SEMAPHORE_NULL) - return KERN_INVALID_ARGUMENT; - - /* - * 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 @@ -233,44 +228,121 @@ semaphore_destroy( semaphore->active = FALSE; /* - * Wakeup blocked threads + * Wakeup blocked threads */ old_count = semaphore->count; 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); + semaphore_dereference(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 * - * Signals the semaphore as direct. + * Signals the semaphore as direct. * Assumptions: * Semaphore is locked. */ kern_return_t semaphore_signal_internal( - semaphore_t semaphore, - thread_t thread, - int options) + semaphore_t semaphore, + thread_t thread, + int options) { kern_return_t kr; spl_t spl_level; @@ -286,51 +358,62 @@ semaphore_signal_internal( if (thread != THREAD_NULL) { if (semaphore->count < 0) { - kr = wait_queue_wakeup64_thread_locked( - &semaphore->wait_queue, - SEMAPHORE_EVENT, - thread, - THREAD_AWAKENED, - TRUE); /* unlock? */ + kr = waitq_wakeup64_thread_locked( + &semaphore->waitq, + SEMAPHORE_EVENT, + thread, + THREAD_AWAKENED, + WAITQ_UNLOCK); + /* waitq/semaphore is unlocked */ } else { - semaphore_unlock(semaphore); kr = KERN_NOT_WAITING; + semaphore_unlock(semaphore); } splx(spl_level); return kr; - } + } 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, - SEMAPHORE_EVENT, - THREAD_AWAKENED, - TRUE); /* unlock? */ + kr = waitq_wakeup64_all_locked( + &semaphore->waitq, + SEMAPHORE_EVENT, + THREAD_AWAKENED, NULL, + WAITQ_ALL_PRIORITIES, + WAITQ_UNLOCK); + /* waitq / semaphore is unlocked */ } else { - if (options & SEMAPHORE_SIGNAL_PREPOST) + 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, - SEMAPHORE_EVENT, - THREAD_AWAKENED, - FALSE) == KERN_SUCCESS) { + waitq_options_t wq_option = (options & SEMAPHORE_THREAD_HANDOFF) ? + WQ_OPTION_HANDOFF : WQ_OPTION_NONE; + kr = waitq_wakeup64_one_locked( + &semaphore->waitq, + SEMAPHORE_EVENT, + THREAD_AWAKENED, NULL, + WAITQ_ALL_PRIORITIES, + WAITQ_KEEP_LOCKED, + wq_option); + 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) { @@ -352,19 +435,20 @@ semaphore_signal_internal( */ kern_return_t semaphore_signal_thread( - semaphore_t semaphore, - thread_t thread) + semaphore_t semaphore, + thread_t thread) { - kern_return_t ret; + kern_return_t ret; - if (semaphore == SEMAPHORE_NULL) + if (semaphore == SEMAPHORE_NULL) { return KERN_INVALID_ARGUMENT; + } ret = semaphore_signal_internal(semaphore, - thread, - SEMAPHORE_OPTION_NONE); + thread, + SEMAPHORE_OPTION_NONE); return ret; -} +} /* * Routine: semaphore_signal_thread_trap @@ -377,27 +461,29 @@ semaphore_signal_thread_trap( { mach_port_name_t sema_name = args->signal_name; mach_port_name_t thread_name = args->thread_name; - semaphore_t semaphore; - thread_t thread; - kern_return_t kr; + semaphore_t semaphore; + thread_t thread; + kern_return_t kr; - /* + /* * MACH_PORT_NULL is not an error. It means that we want to * select any one thread that is already waiting, but not to * pre-post the semaphore. */ if (thread_name != MACH_PORT_NULL) { - thread = port_name_to_thread(thread_name); - if (thread == THREAD_NULL) + thread = port_name_to_thread(thread_name, PORT_TO_THREAD_NONE); + if (thread == THREAD_NULL) { return KERN_INVALID_ARGUMENT; - } else + } + } else { thread = THREAD_NULL; + } kr = port_name_to_semaphore(sema_name, &semaphore); if (kr == KERN_SUCCESS) { kr = semaphore_signal_internal(semaphore, - thread, - SEMAPHORE_OPTION_NONE); + thread, + SEMAPHORE_OPTION_NONE); semaphore_dereference(semaphore); } if (thread != THREAD_NULL) { @@ -421,18 +507,20 @@ semaphore_signal_thread_trap( */ kern_return_t semaphore_signal( - semaphore_t semaphore) + semaphore_t semaphore) { - kern_return_t kr; + kern_return_t kr; - if (semaphore == SEMAPHORE_NULL) + if (semaphore == SEMAPHORE_NULL) { return KERN_INVALID_ARGUMENT; + } kr = semaphore_signal_internal(semaphore, - THREAD_NULL, - SEMAPHORE_SIGNAL_PREPOST); - if (kr == KERN_NOT_WAITING) + THREAD_NULL, + SEMAPHORE_SIGNAL_PREPOST); + if (kr == KERN_NOT_WAITING) { return KERN_SUCCESS; + } return kr; } @@ -446,17 +534,25 @@ semaphore_signal_trap( struct semaphore_signal_trap_args *args) { mach_port_name_t sema_name = args->signal_name; - semaphore_t semaphore; + + 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; kr = port_name_to_semaphore(sema_name, &semaphore); if (kr == KERN_SUCCESS) { - kr = semaphore_signal_internal(semaphore, - THREAD_NULL, - SEMAPHORE_SIGNAL_PREPOST); + kr = semaphore_signal_internal(semaphore, + THREAD_NULL, + SEMAPHORE_SIGNAL_PREPOST); semaphore_dereference(semaphore); - if (kr == KERN_NOT_WAITING) + if (kr == KERN_NOT_WAITING) { kr = KERN_SUCCESS; + } } return kr; } @@ -469,18 +565,20 @@ semaphore_signal_trap( */ kern_return_t semaphore_signal_all( - semaphore_t semaphore) + semaphore_t semaphore) { kern_return_t kr; - if (semaphore == SEMAPHORE_NULL) + if (semaphore == SEMAPHORE_NULL) { return KERN_INVALID_ARGUMENT; + } kr = semaphore_signal_internal(semaphore, - THREAD_NULL, - SEMAPHORE_SIGNAL_ALL); - if (kr == KERN_NOT_WAITING) + THREAD_NULL, + SEMAPHORE_SIGNAL_ALL); + if (kr == KERN_NOT_WAITING) { return KERN_SUCCESS; + } return kr; } @@ -494,17 +592,18 @@ semaphore_signal_all_trap( struct semaphore_signal_all_trap_args *args) { mach_port_name_t sema_name = args->signal_name; - semaphore_t semaphore; + semaphore_t semaphore; kern_return_t kr; kr = port_name_to_semaphore(sema_name, &semaphore); if (kr == KERN_SUCCESS) { kr = semaphore_signal_internal(semaphore, - THREAD_NULL, - SEMAPHORE_SIGNAL_ALL); + THREAD_NULL, + SEMAPHORE_SIGNAL_ALL); semaphore_dereference(semaphore); - if (kr == KERN_NOT_WAITING) + if (kr == KERN_NOT_WAITING) { kr = KERN_SUCCESS; + } } return kr; } @@ -525,7 +624,7 @@ semaphore_convert_wait_result(int wait_result) case THREAD_TIMED_OUT: return KERN_OPERATION_TIMED_OUT; - + case THREAD_INTERRUPTED: return KERN_ABORTED; @@ -545,19 +644,20 @@ semaphore_convert_wait_result(int wait_result) * It returns directly to user space. */ void -semaphore_wait_continue(void) +semaphore_wait_continue(void *arg __unused, wait_result_t wr) { thread_t self = current_thread(); - int wait_result = self->wait_result; void (*caller_cont)(kern_return_t) = self->sth_continuation; assert(self->sth_waitsemaphore != SEMAPHORE_NULL); semaphore_dereference(self->sth_waitsemaphore); - if (self->sth_signalsemaphore != SEMAPHORE_NULL) + if (self->sth_signalsemaphore != SEMAPHORE_NULL) { semaphore_dereference(self->sth_signalsemaphore); + } + assert(self->handoff_thread == THREAD_NULL); assert(caller_cont != (void (*)(kern_return_t))0); - (*caller_cont)(semaphore_convert_wait_result(wait_result)); + (*caller_cont)(semaphore_convert_wait_result(wr)); } /* @@ -571,59 +671,45 @@ 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, - void (*caller_cont)(kern_return_t)) + semaphore_t wait_semaphore, + semaphore_t signal_semaphore, + 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; + int wait_result; + spl_t spl_level; + kern_return_t kr = KERN_ALREADY_WAITING; 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; + thread_t self = current_thread(); + thread_t handoff_thread = THREAD_NULL; + thread_handoff_option_t handoff_option = THREAD_HANDOFF_NONE; + int semaphore_signal_options = SEMAPHORE_SIGNAL_PREPOST; 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, - SEMAPHORE_EVENT, - THREAD_ABORTSAFE, abstime, - self); - thread_unlock(self); + thread_set_pending_block_hint(self, kThreadWaitSemaphore); + (void)waitq_assert_wait64_locked( + &wait_semaphore->waitq, + SEMAPHORE_EVENT, + THREAD_ABORTSAFE, + TIMEOUT_URGENCY_USER_NORMAL, + deadline, TIMEOUT_NO_LEEWAY, + self); + + semaphore_signal_options |= SEMAPHORE_THREAD_HANDOFF; } semaphore_unlock(wait_semaphore); splx(spl_level); @@ -641,13 +727,13 @@ semaphore_wait_internal( * our intention to wait above). */ signal_kr = semaphore_signal_internal(signal_semaphore, - THREAD_NULL, - SEMAPHORE_SIGNAL_PREPOST); + THREAD_NULL, semaphore_signal_options); - if (signal_kr == KERN_NOT_WAITING) + if (signal_kr == KERN_NOT_WAITING) { + assert(self->handoff_thread == THREAD_NULL); signal_kr = KERN_SUCCESS; - else if (signal_kr == KERN_TERMINATED) { - /* + } else if (signal_kr == KERN_TERMINATED) { + /* * Uh!Oh! The semaphore we were to signal died. * We have to get ourselves out of the wait in * case we get stuck here forever (it is assumed @@ -660,42 +746,49 @@ semaphore_wait_internal( * (most important) result. Otherwise, * return the KERN_TERMINATED status. */ - thread_t self = current_thread(); - + assert(self->handoff_thread == THREAD_NULL); clear_wait(self, THREAD_INTERRUPTED); kr = semaphore_convert_wait_result(self->wait_result); - if (kr == KERN_ABORTED) + if (kr == KERN_ABORTED) { kr = KERN_TERMINATED; + } } } - + /* * If we had an error, or we didn't really need to wait we can * return now that we have signalled the signal semaphore. */ - if (kr != KERN_ALREADY_WAITING) + if (kr != KERN_ALREADY_WAITING) { + assert(self->handoff_thread == THREAD_NULL); return kr; + } + if (self->handoff_thread) { + handoff_thread = self->handoff_thread; + self->handoff_thread = THREAD_NULL; + handoff_option = THREAD_HANDOFF_SETRUN_NEEDED; + } /* * Now, we can block. If the caller supplied a continuation * pointer of his own for after the block, block with the - * appropriate semaphore continuation. Thiswill gather the + * appropriate semaphore continuation. This will gather the * semaphore results, release references on the semaphore(s), * and then call the caller's continuation. */ if (caller_cont) { - thread_t self = current_thread(); - self->sth_continuation = caller_cont; self->sth_waitsemaphore = wait_semaphore; self->sth_signalsemaphore = signal_semaphore; - wait_result = thread_block((thread_continue_t)semaphore_wait_continue); - } - else { - wait_result = thread_block(THREAD_CONTINUE_NULL); + + thread_handoff_parameter(handoff_thread, semaphore_wait_continue, + NULL, handoff_option); + } else { + wait_result = thread_handoff_deallocate(handoff_thread, handoff_option); } - return (semaphore_convert_wait_result(wait_result)); + assert(self->handoff_thread == THREAD_NULL); + return semaphore_convert_wait_result(wait_result); } @@ -703,20 +796,49 @@ semaphore_wait_internal( * Routine: semaphore_wait * * Traditional (non-continuation) interface presented to - * in-kernel clients to wait on a semaphore. + * in-kernel clients to wait on a semaphore. */ kern_return_t semaphore_wait( - semaphore_t semaphore) -{ + semaphore_t semaphore) +{ + if (semaphore == SEMAPHORE_NULL) { + return KERN_INVALID_ARGUMENT; + } + + return semaphore_wait_internal(semaphore, + SEMAPHORE_NULL, + 0ULL, SEMAPHORE_OPTION_NONE, + (void (*)(kern_return_t))0); +} - if (semaphore == SEMAPHORE_NULL) +kern_return_t +semaphore_wait_noblock( + semaphore_t semaphore) +{ + if (semaphore == SEMAPHORE_NULL) { return KERN_INVALID_ARGUMENT; + } - return(semaphore_wait_internal(semaphore, - SEMAPHORE_NULL, - (mach_timespec_t *)0, - (void (*)(kern_return_t))0)); + 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); } /* @@ -730,25 +852,25 @@ kern_return_t semaphore_wait_trap( struct semaphore_wait_trap_args *args) { - return(semaphore_wait_trap_internal(args->wait_name, thread_syscall_return)); + return semaphore_wait_trap_internal(args->wait_name, thread_syscall_return); } kern_return_t semaphore_wait_trap_internal( - mach_port_name_t name, + mach_port_name_t name, void (*caller_cont)(kern_return_t)) -{ - semaphore_t semaphore; +{ + semaphore_t semaphore; kern_return_t kr; kr = port_name_to_semaphore(name, &semaphore); if (kr == KERN_SUCCESS) { kr = semaphore_wait_internal(semaphore, - SEMAPHORE_NULL, - (mach_timespec_t *)0, - caller_cont); + SEMAPHORE_NULL, + 0ULL, SEMAPHORE_OPTION_NONE, + caller_cont); semaphore_dereference(semaphore); } return kr; @@ -758,26 +880,36 @@ semaphore_wait_trap_internal( * Routine: semaphore_timedwait * * Traditional (non-continuation) interface presented to - * in-kernel clients to wait on a semaphore with a timeout. + * in-kernel clients to wait on a semaphore with a timeout. * * A timeout of {0,0} is considered non-blocking. */ kern_return_t semaphore_timedwait( - semaphore_t semaphore, - mach_timespec_t wait_time) -{ - if (semaphore == SEMAPHORE_NULL) + 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)) + } + + if (BAD_MACH_TIMESPEC(&wait_time)) { return KERN_INVALID_VALUE; - - return (semaphore_wait_internal(semaphore, - SEMAPHORE_NULL, - &wait_time, - (void(*)(kern_return_t))0)); - + } + + 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, + deadline, option, + (void (*)(kern_return_t))0); } /* @@ -794,9 +926,8 @@ semaphore_timedwait( kern_return_t semaphore_timedwait_trap( struct semaphore_timedwait_trap_args *args) -{ - - return(semaphore_timedwait_trap_internal(args->wait_name, args->sec, args->nsec, thread_syscall_return)); +{ + return semaphore_timedwait_trap_internal(args->wait_name, args->sec, args->nsec, thread_syscall_return); } @@ -807,22 +938,31 @@ 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; wait_time.tv_sec = sec; wait_time.tv_nsec = nsec; - if(BAD_MACH_TIMESPEC(&wait_time)) + if (BAD_MACH_TIMESPEC(&wait_time)) { return KERN_INVALID_VALUE; - + } + 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, - caller_cont); + SEMAPHORE_NULL, + deadline, option, + caller_cont); semaphore_dereference(semaphore); } return kr; @@ -838,29 +978,30 @@ semaphore_timedwait_trap_internal( */ kern_return_t semaphore_wait_signal( - semaphore_t wait_semaphore, - semaphore_t signal_semaphore) + semaphore_t wait_semaphore, + semaphore_t signal_semaphore) { - if (wait_semaphore == SEMAPHORE_NULL) + if (wait_semaphore == SEMAPHORE_NULL) { return KERN_INVALID_ARGUMENT; - - return(semaphore_wait_internal(wait_semaphore, - signal_semaphore, - (mach_timespec_t *)0, - (void(*)(kern_return_t))0)); + } + + return semaphore_wait_internal(wait_semaphore, + signal_semaphore, + 0ULL, SEMAPHORE_OPTION_NONE, + (void (*)(kern_return_t))0); } /* * Trap: semaphore_wait_signal_trap * * Atomically register a wait on a semaphore and THEN signal - * another. This is the trap version from user space. + * another. This is the trap version from user space. */ kern_return_t semaphore_wait_signal_trap( struct semaphore_wait_signal_trap_args *args) { - return(semaphore_wait_signal_trap_internal(args->wait_name, args->signal_name, thread_syscall_return)); + return semaphore_wait_signal_trap_internal(args->wait_name, args->signal_name, thread_syscall_return); } kern_return_t @@ -878,9 +1019,9 @@ semaphore_wait_signal_trap_internal( kr = port_name_to_semaphore(wait_name, &wait_semaphore); if (kr == KERN_SUCCESS) { kr = semaphore_wait_internal(wait_semaphore, - signal_semaphore, - (mach_timespec_t *)0, - caller_cont); + signal_semaphore, + 0ULL, SEMAPHORE_OPTION_NONE, + caller_cont); semaphore_dereference(wait_semaphore); } semaphore_dereference(signal_semaphore); @@ -900,33 +1041,44 @@ semaphore_wait_signal_trap_internal( */ kern_return_t semaphore_timedwait_signal( - semaphore_t wait_semaphore, - semaphore_t signal_semaphore, - mach_timespec_t wait_time) + semaphore_t wait_semaphore, + semaphore_t signal_semaphore, + mach_timespec_t wait_time) { - if (wait_semaphore == SEMAPHORE_NULL) + int option = SEMAPHORE_OPTION_NONE; + uint64_t deadline = 0; + + if (wait_semaphore == SEMAPHORE_NULL) { return KERN_INVALID_ARGUMENT; - - if(BAD_MACH_TIMESPEC(&wait_time)) + } + + if (BAD_MACH_TIMESPEC(&wait_time)) { return KERN_INVALID_VALUE; - - return(semaphore_wait_internal(wait_semaphore, - signal_semaphore, - &wait_time, - (void(*)(kern_return_t))0)); + } + + 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, + deadline, option, + (void (*)(kern_return_t))0); } /* * Trap: semaphore_timedwait_signal_trap * * Atomically register a timed wait on a semaphore and THEN signal - * another. This is the trap version from user space. + * another. This is the trap version from user space. */ kern_return_t semaphore_timedwait_signal_trap( struct semaphore_timedwait_signal_trap_args *args) { - return(semaphore_timedwait_signal_trap_internal(args->wait_name, args->signal_name, args->sec, args->nsec, thread_syscall_return)); + return semaphore_timedwait_signal_trap_internal(args->wait_name, args->signal_name, args->sec, args->nsec, thread_syscall_return); } kern_return_t @@ -944,17 +1096,27 @@ semaphore_timedwait_signal_trap_internal( wait_time.tv_sec = sec; wait_time.tv_nsec = nsec; - if(BAD_MACH_TIMESPEC(&wait_time)) + if (BAD_MACH_TIMESPEC(&wait_time)) { return KERN_INVALID_VALUE; - + } + kr = port_name_to_semaphore(signal_name, &signal_semaphore); 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, - caller_cont); + signal_semaphore, + deadline, option, + caller_cont); semaphore_dereference(wait_semaphore); } semaphore_dereference(signal_semaphore); @@ -971,17 +1133,9 @@ semaphore_timedwait_signal_trap_internal( */ void semaphore_reference( - semaphore_t semaphore) + semaphore_t semaphore) { - spl_t spl_level; - - spl_level = splsched(); - semaphore_lock(semaphore); - - semaphore->ref_count++; - - semaphore_unlock(semaphore); - splx(spl_level); + os_ref_retain(&semaphore->ref_count); } /* @@ -992,23 +1146,76 @@ semaphore_reference( */ void semaphore_dereference( - semaphore_t semaphore) + semaphore_t semaphore) { - int ref_count; - spl_t spl_level; + uint32_t collisions; + spl_t spl_level; + + if (semaphore == NULL) { + return; + } + + if (os_ref_release(&semaphore->ref_count) > 0) { + return; + } - if (semaphore != NULL) { - spl_level = splsched(); - semaphore_lock(semaphore); + /* + * 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); + } - ref_count = --(semaphore->ref_count); + /* + * 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); - semaphore_unlock(semaphore); - splx(spl_level); + zone_require(semaphore_zone, sem); - if (ref_count == 0) { - assert(wait_queue_empty(&semaphore->wait_queue)); - zfree(semaphore_zone, semaphore); - } + waitinfo->context = VM_KERNEL_UNSLIDE_OR_PERM(sem->port); + if (sem->owner) { + waitinfo->owner = pid_from_task(sem->owner); } }