/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2020 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
- * @APPLE_LICENSE_HEADER_START@
- *
- * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
- *
* 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. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- *
+ * 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,
* 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@
- *
+ *
*/
/*
* File: kern/sync_sema.c
*/
#include <mach/mach_types.h>
+#include <mach/mach_traps.h>
#include <mach/kern_return.h>
#include <mach/semaphore.h>
#include <mach/sync_policy.h>
+#include <mach/task.h>
#include <kern/misc_protos.h>
#include <kern/sync_sema.h>
#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;
+ZONE_DECLARE(semaphore_zone, "semaphores", sizeof(struct semaphore), ZC_NONE);
+
+os_refgrp_decl(static, sema_refgrp, "semaphore", NULL);
+
+/* Forward declarations */
+
+
+kern_return_t
+semaphore_wait_trap_internal(
+ mach_port_name_t name,
+ void (*caller_cont)(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));
+
+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));
+
+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));
+
+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);
+
+kern_return_t
+semaphore_convert_wait_result(
+ int wait_result);
-/*
- * ROUTINE: semaphore_init [private]
- *
- * Initialize the semaphore mechanisms.
- * Right now, we only need to initialize the semaphore zone.
- */
void
-semaphore_init(void)
+semaphore_wait_continue(void *arg __unused, wait_result_t wr);
+
+static kern_return_t
+semaphore_wait_internal(
+ 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;
}
/*
*/
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;
- thread_t thread;
- 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->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_act_t thread_act,
- int options)
+ semaphore_t semaphore,
+ thread_t thread,
+ int options)
{
kern_return_t kr;
spl_t spl_level;
return KERN_TERMINATED;
}
- if (thread_act != THR_ACT_NULL) {
+ if (thread != THREAD_NULL) {
if (semaphore->count < 0) {
- kr = wait_queue_wakeup64_thread_locked(
- &semaphore->wait_queue,
- SEMAPHORE_EVENT,
- thread_act->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) {
/*
* Routine: semaphore_signal_thread
*
- * If the specified thread_act is blocked on the semaphore, it is
- * woken up. If a NULL thread_act was supplied, then any one
+ * If the specified thread is blocked on the semaphore, it is
+ * woken up. If a NULL thread was supplied, then any one
* thread is woken up. Otherwise the caller gets KERN_NOT_WAITING
* and the semaphore is unchanged.
*/
kern_return_t
semaphore_signal_thread(
- semaphore_t semaphore,
- thread_act_t thread_act)
+ 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_act,
- SEMAPHORE_OPTION_NONE);
+ thread,
+ SEMAPHORE_OPTION_NONE);
return ret;
-}
+}
/*
* Routine: semaphore_signal_thread_trap
*/
kern_return_t
semaphore_signal_thread_trap(
- mach_port_name_t sema_name,
- mach_port_name_t thread_name)
+ struct semaphore_signal_thread_trap_args *args)
{
-
- semaphore_t semaphore;
- thread_act_t thread_act;
- kern_return_t kr;
+ 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;
- /*
+ /*
* 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_act = port_name_to_act(thread_name);
- if (thread_act == THR_ACT_NULL)
+ thread = port_name_to_thread(thread_name, PORT_TO_THREAD_NONE);
+ if (thread == THREAD_NULL) {
return KERN_INVALID_ARGUMENT;
- } else
- thread_act = THR_ACT_NULL;
+ }
+ } else {
+ thread = THREAD_NULL;
+ }
kr = port_name_to_semaphore(sema_name, &semaphore);
- if (kr != KERN_SUCCESS) {
- act_deallocate(thread_act);
- return kr;
+ if (kr == KERN_SUCCESS) {
+ kr = semaphore_signal_internal(semaphore,
+ thread,
+ SEMAPHORE_OPTION_NONE);
+ semaphore_dereference(semaphore);
+ }
+ if (thread != THREAD_NULL) {
+ thread_deallocate(thread);
}
- kr = semaphore_signal_internal(semaphore,
- thread_act,
- SEMAPHORE_OPTION_NONE);
- semaphore_dereference(semaphore);
- act_deallocate(thread_act);
return kr;
}
*/
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,
- THR_ACT_NULL,
- SEMAPHORE_SIGNAL_PREPOST);
- if (kr == KERN_NOT_WAITING)
+ THREAD_NULL,
+ SEMAPHORE_SIGNAL_PREPOST);
+ if (kr == KERN_NOT_WAITING) {
return KERN_SUCCESS;
+ }
return kr;
}
*/
kern_return_t
semaphore_signal_trap(
- mach_port_name_t sema_name)
+ 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;
+ semaphore_t semaphore;
kern_return_t kr;
kr = port_name_to_semaphore(sema_name, &semaphore);
- if (kr != KERN_SUCCESS) {
- return kr;
+ if (kr == KERN_SUCCESS) {
+ kr = semaphore_signal_internal(semaphore,
+ THREAD_NULL,
+ SEMAPHORE_SIGNAL_PREPOST);
+ semaphore_dereference(semaphore);
+ if (kr == KERN_NOT_WAITING) {
+ kr = KERN_SUCCESS;
+ }
}
- kr = semaphore_signal_internal(semaphore,
- THR_ACT_NULL,
- SEMAPHORE_SIGNAL_PREPOST);
- semaphore_dereference(semaphore);
- if (kr == KERN_NOT_WAITING)
- return KERN_SUCCESS;
return kr;
}
*/
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,
- THR_ACT_NULL,
- SEMAPHORE_SIGNAL_ALL);
- if (kr == KERN_NOT_WAITING)
+ THREAD_NULL,
+ SEMAPHORE_SIGNAL_ALL);
+ if (kr == KERN_NOT_WAITING) {
return KERN_SUCCESS;
+ }
return kr;
}
*/
kern_return_t
semaphore_signal_all_trap(
- mach_port_name_t sema_name)
+ struct semaphore_signal_all_trap_args *args)
{
-
- semaphore_t semaphore;
+ mach_port_name_t sema_name = args->signal_name;
+ semaphore_t semaphore;
kern_return_t kr;
kr = port_name_to_semaphore(sema_name, &semaphore);
- if (kr != KERN_SUCCESS) {
- return kr;
+ if (kr == KERN_SUCCESS) {
+ kr = semaphore_signal_internal(semaphore,
+ THREAD_NULL,
+ SEMAPHORE_SIGNAL_ALL);
+ semaphore_dereference(semaphore);
+ if (kr == KERN_NOT_WAITING) {
+ kr = KERN_SUCCESS;
+ }
}
- kr = semaphore_signal_internal(semaphore,
- THR_ACT_NULL,
- SEMAPHORE_SIGNAL_ALL);
- semaphore_dereference(semaphore);
- if (kr == KERN_NOT_WAITING)
- return KERN_SUCCESS;
return kr;
}
case THREAD_TIMED_OUT:
return KERN_OPERATION_TIMED_OUT;
-
+
case THREAD_INTERRUPTED:
return KERN_ABORTED;
* 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)
- semaphore_dereference(self->sth_signalsemaphore);
-
- assert(caller_cont != (void (*)(kern_return_t))0);
- (*caller_cont)(semaphore_convert_wait_result(wait_result));
-}
-
-/*
- * Routine: semaphore_timedwait_continue
- *
- * Common continuation routine after doing a timed wait on a
- * semaphore. It clears the timer before calling the semaphore
- * routine saved in the thread struct.
- */
-void
-semaphore_timedwait_continue(void)
-{
- thread_t self = current_thread();
- int wait_result = self->wait_result;
- void (*caller_cont)(kern_return_t) = self->sth_continuation;
-
- if (wait_result != THREAD_TIMED_OUT)
- thread_cancel_timer();
-
- 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));
}
-
/*
* Routine: semaphore_wait_internal
*
* 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))
-{
- void (*continuation)(void);
- uint64_t abstime, nsinterval;
- boolean_t nonblocking;
- int wait_result;
- spl_t spl_level;
- kern_return_t kr = KERN_ALREADY_WAITING;
+ semaphore_t wait_semaphore,
+ semaphore_t signal_semaphore,
+ uint64_t deadline,
+ int option,
+ void (*caller_cont)(kern_return_t))
+{
+ 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 {
+ } else {
wait_semaphore->count = -1; /* we don't keep an actual count */
- (void)wait_queue_assert_wait64_locked(
- &wait_semaphore->wait_queue,
- SEMAPHORE_EVENT,
- THREAD_ABORTSAFE,
- FALSE); /* unlock? */
+
+ 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);
* our intention to wait above).
*/
signal_kr = semaphore_signal_internal(signal_semaphore,
- THR_ACT_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
* (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 it is a timed wait, go ahead and set up the timer.
- */
- if (wait_timep != (mach_timespec_t *)0) {
- clock_interval_to_absolutetime_interval(wait_timep->tv_sec,
- NSEC_PER_SEC,
- &abstime);
- clock_interval_to_absolutetime_interval(wait_timep->tv_nsec,
- 1,
- &nsinterval);
- abstime += nsinterval;
- clock_absolutetime_interval_to_deadline(abstime, &abstime);
- thread_set_timer_deadline(abstime);
- continuation = semaphore_timedwait_continue;
- } else {
- continuation = semaphore_wait_continue;
}
+ 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(continuation);
+
+ thread_handoff_parameter(handoff_thread, semaphore_wait_continue,
+ NULL, handoff_option);
} else {
- wait_result = thread_block(THREAD_CONTINUE_NULL);
+ wait_result = thread_handoff_deallocate(handoff_thread, handoff_option);
}
- /*
- * If we came back here (not continuation case) cancel
- * any pending timers, convert the wait result to an
- * appropriate semaphore return value, and then return
- * that.
- */
- if (wait_timep && (wait_result != THREAD_TIMED_OUT))
- thread_cancel_timer();
-
- return (semaphore_convert_wait_result(wait_result));
+ assert(self->handoff_thread == THREAD_NULL);
+ return semaphore_convert_wait_result(wait_result);
}
* 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);
}
/*
* Trap version of semaphore wait. Called on behalf of user-level
* clients.
*/
+
kern_return_t
semaphore_wait_trap(
- mach_port_name_t name)
-{
- semaphore_t semaphore;
+ struct semaphore_wait_trap_args *args)
+{
+ return semaphore_wait_trap_internal(args->wait_name, thread_syscall_return);
+}
+
+
+
+kern_return_t
+semaphore_wait_trap_internal(
+ mach_port_name_t name,
+ void (*caller_cont)(kern_return_t))
+{
+ semaphore_t semaphore;
kern_return_t kr;
kr = port_name_to_semaphore(name, &semaphore);
- if (kr != KERN_SUCCESS)
- return kr;
-
- kr = semaphore_wait_internal(semaphore,
- SEMAPHORE_NULL,
- (mach_timespec_t *)0,
- thread_syscall_return);
- semaphore_dereference(semaphore);
+ if (kr == KERN_SUCCESS) {
+ kr = semaphore_wait_internal(semaphore,
+ SEMAPHORE_NULL,
+ 0ULL, SEMAPHORE_OPTION_NONE,
+ caller_cont);
+ semaphore_dereference(semaphore);
+ }
return kr;
}
* 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);
}
/*
*/
kern_return_t
semaphore_timedwait_trap(
- mach_port_name_t name,
- unsigned int sec,
- clock_res_t nsec)
-{
+ struct semaphore_timedwait_trap_args *args)
+{
+ return semaphore_timedwait_trap_internal(args->wait_name, args->sec, args->nsec, thread_syscall_return);
+}
+
+
+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))
+{
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)
- return kr;
+ if (kr == KERN_SUCCESS) {
+ int option = SEMAPHORE_OPTION_NONE;
+ uint64_t deadline = 0;
- kr = semaphore_wait_internal(semaphore,
- SEMAPHORE_NULL,
- &wait_time,
- thread_syscall_return);
- semaphore_dereference(semaphore);
+ if (sec == 0 && nsec == 0) {
+ option = SEMAPHORE_TIMEOUT_NOBLOCK;
+ } else {
+ deadline = semaphore_deadline(sec, nsec);
+ }
+
+ kr = semaphore_wait_internal(semaphore,
+ SEMAPHORE_NULL,
+ deadline, option,
+ caller_cont);
+ semaphore_dereference(semaphore);
+ }
return kr;
}
*/
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(
- mach_port_name_t wait_name,
- mach_port_name_t signal_name)
+ struct semaphore_wait_signal_trap_args *args)
+{
+ return semaphore_wait_signal_trap_internal(args->wait_name, args->signal_name, thread_syscall_return);
+}
+
+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))
{
semaphore_t wait_semaphore;
semaphore_t signal_semaphore;
kern_return_t kr;
kr = port_name_to_semaphore(signal_name, &signal_semaphore);
- if (kr != KERN_SUCCESS)
- return kr;
-
- kr = port_name_to_semaphore(wait_name, &wait_semaphore);
- if (kr != KERN_SUCCESS) {
+ if (kr == KERN_SUCCESS) {
+ kr = port_name_to_semaphore(wait_name, &wait_semaphore);
+ if (kr == KERN_SUCCESS) {
+ kr = semaphore_wait_internal(wait_semaphore,
+ signal_semaphore,
+ 0ULL, SEMAPHORE_OPTION_NONE,
+ caller_cont);
+ semaphore_dereference(wait_semaphore);
+ }
semaphore_dereference(signal_semaphore);
- return kr;
}
-
- kr = semaphore_wait_internal(wait_semaphore,
- signal_semaphore,
- (mach_timespec_t *)0,
- thread_syscall_return);
-
- semaphore_dereference(wait_semaphore);
- semaphore_dereference(signal_semaphore);
return kr;
}
*/
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(
- mach_port_name_t wait_name,
- mach_port_name_t signal_name,
- unsigned int sec,
- clock_res_t nsec)
+ 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);
+}
+
+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))
{
semaphore_t wait_semaphore;
semaphore_t signal_semaphore;
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)
- return kr;
+ }
- kr = port_name_to_semaphore(wait_name, &wait_semaphore);
- if (kr != KERN_SUCCESS) {
+ 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,
+ deadline, option,
+ caller_cont);
+ semaphore_dereference(wait_semaphore);
+ }
semaphore_dereference(signal_semaphore);
- return kr;
}
-
- kr = semaphore_wait_internal(wait_semaphore,
- signal_semaphore,
- &wait_time,
- thread_syscall_return);
-
- semaphore_dereference(wait_semaphore);
- semaphore_dereference(signal_semaphore);
return kr;
}
*/
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);
}
/*
*/
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;
+ }
+
+ /*
+ * 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);
+ }
+
+ /*
+ * 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;
- if (semaphore != NULL) {
- spl_level = splsched();
- semaphore_lock(semaphore);
+ assert(task != TASK_NULL);
- ref_count = --(semaphore->ref_count);
+ 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, (vm_offset_t)semaphore);
- }
+ waitinfo->context = VM_KERNEL_UNSLIDE_OR_PERM(sem->port);
+ if (sem->owner) {
+ waitinfo->owner = pid_from_task(sem->owner);
}
}
projects / apple / xnu.git / blobdiff