/*
- * 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@
#include <ipc/ipc_port.h>
#include <ipc/ipc_space.h>
#include <kern/host.h>
-#include <kern/wait_queue.h>
+#include <kern/waitq.h>
#include <kern/zalloc.h>
#include <kern/mach_param.h>
+#include <libkern/OSAtomic.h>
+
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 */
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(
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));
+void
+kdp_sema_find_owner(
+ struct waitq * waitq,
+ event64_t event,
+ thread_waitinfo_t * waitinfo);
+
+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]
*
semaphore_max * sizeof(struct semaphore),
sizeof(struct semaphore),
"semaphores");
+ zone_change(semaphore_zone, Z_NOENCRYPT, TRUE);
}
/*
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;
}
/*
- * 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;
-
+ 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
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
*
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;
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) {
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;
* 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;
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);
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));
}
if (kr == KERN_SUCCESS) {
kr = semaphore_wait_internal(semaphore,
SEMAPHORE_NULL,
- (mach_timespec_t *)0,
+ 0ULL, SEMAPHORE_OPTION_NONE,
caller_cont);
semaphore_dereference(semaphore);
}
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));
}
clock_res_t nsec,
void (*caller_cont)(kern_return_t))
{
-
semaphore_t semaphore;
mach_timespec_t wait_time;
kern_return_t kr;
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);
}
return(semaphore_wait_internal(wait_semaphore,
signal_semaphore,
- (mach_timespec_t *)0,
+ 0ULL, SEMAPHORE_OPTION_NONE,
(void(*)(kern_return_t))0));
}
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);
}
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));
}
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);
}
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);
}
/*
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);
}
projects / apple / xnu.git / blobdiff