[apple/libpthread.git] / src / pthread_dependency.c

/*
 * Copyright (c) 2018 Apple Inc. All rights reserved.
 *
 * @APPLE_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. 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_LICENSE_HEADER_END@
 */

#include "resolver.h"
#include "internal.h"

#define PREREQUISITE_FULFILLED  (~0u)

#if !VARIANT_DYLD
void
pthread_dependency_init_np(pthread_dependency_t *pr, pthread_t pth,
		pthread_dependency_attr_t *attrs)
{
	if (attrs) *(volatile char *)attrs;
	*pr = (pthread_dependency_t)PTHREAD_DEPENDENCY_INITIALIZER_NP(pth);
}

OS_NOINLINE
void
_pthread_dependency_fulfill_slow(pthread_dependency_t *pr, uint32_t old)
{
	if (old == PREREQUISITE_FULFILLED) {
		PTHREAD_CLIENT_CRASH(0, "Fufilling pthread_dependency_t twice");
	}
	if (os_unlikely(old != _pthread_mach_thread_self_direct())) {
		PTHREAD_CLIENT_CRASH(old, "Fulfilled a dependency "
				"not owned by current thread");
	}

	int ret = __ulock_wake(UL_UNFAIR_LOCK | ULF_NO_ERRNO, &pr->__pdep_opaque1, 0);
	switch (-ret) {
	case 0:
	case ENOENT:
		return;
	default:
		PTHREAD_INTERNAL_CRASH(-ret, "__ulock_wake() failed");
	}
}


PTHREAD_NOEXPORT_VARIANT
void
pthread_dependency_fulfill_np(pthread_dependency_t *pr, void *value)
{
	uint32_t old;

	pr->__pdep_opaque2 = (uint64_t)(uintptr_t)value;
	old = os_atomic_xchg(&pr->__pdep_opaque1, PREREQUISITE_FULFILLED, release);

	if (old != 0) _pthread_dependency_fulfill_slow(pr, old);
}

PTHREAD_NOEXPORT_VARIANT
void *
pthread_dependency_wait_np(pthread_dependency_t *pr)
{
	if (os_atomic_cmpxchg(&pr->__pdep_opaque1, 0, pr->__pdep_owner, relaxed)) {
		int ret;
	again:
		ret = __ulock_wait(UL_UNFAIR_LOCK | ULF_NO_ERRNO, &pr->__pdep_opaque1,
				pr->__pdep_owner, 0);
		switch (-ret) {
		case EFAULT:
		case EINTR:
		case 0:
			if (pr->__pdep_opaque1 == pr->__pdep_owner) goto again;
			break;
		case EOWNERDEAD:
			PTHREAD_CLIENT_CRASH(pr->__pdep_owner, "Waiting on orphaned dependency");
		default:
			PTHREAD_CLIENT_CRASH(-ret, "__ulock_wait() failed");
		}
	}

	uint32_t cur = os_atomic_load(&pr->__pdep_opaque1, acquire);
	if (cur == PREREQUISITE_FULFILLED) {
		return (void *)(uintptr_t)pr->__pdep_opaque2;
	}
	PTHREAD_CLIENT_CRASH(cur, "Corrupted pthread_dependency_t");
}

PTHREAD_NOEXPORT_VARIANT void*
_pthread_atomic_xchg_ptr(void **p, void *v)
{
	return os_atomic_xchg(p, v, seq_cst);
}

PTHREAD_NOEXPORT_VARIANT uint32_t
_pthread_atomic_xchg_uint32_relaxed(uint32_t *p, uint32_t v)
{
	return os_atomic_xchg(p, v, relaxed);
}

#endif // !VARIANT_DYLD
Commit	Line	Data
214d78a2 A	1	/*
	2	* Copyright (c) 2018 Apple Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. Please obtain a copy of the License at
	10	* http://www.opensource.apple.com/apsl/ and read it before using this
	11	* file.
	12	*
	13	* The Original Code and all software distributed under the License are
	14	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	15	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	16	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	17	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	18	* Please see the License for the specific language governing rights and
	19	* limitations under the License.
	20	*
	21	* @APPLE_LICENSE_HEADER_END@
	22	*/
	23
	24	#include "resolver.h"
	25	#include "internal.h"
214d78a2 A	26
	27	#define PREREQUISITE_FULFILLED (~0u)
	28
c1f56ec9	29	#if !VARIANT_DYLD
214d78a2 A	30	void
	31	pthread_dependency_init_np(pthread_dependency_t *pr, pthread_t pth,
	32	pthread_dependency_attr_t *attrs)
	33	{
	34	if (attrs) (volatile char )attrs;
	35	*pr = (pthread_dependency_t)PTHREAD_DEPENDENCY_INITIALIZER_NP(pth);
	36	}
	37
	38	OS_NOINLINE
	39	void
	40	_pthread_dependency_fulfill_slow(pthread_dependency_t *pr, uint32_t old)
	41	{
	42	if (old == PREREQUISITE_FULFILLED) {
	43	PTHREAD_CLIENT_CRASH(0, "Fufilling pthread_dependency_t twice");
	44	}
c1f56ec9	45	if (os_unlikely(old != _pthread_mach_thread_self_direct())) {
214d78a2 A	46	PTHREAD_CLIENT_CRASH(old, "Fulfilled a dependency "
	47	"not owned by current thread");
	48	}
	49
	50	int ret = __ulock_wake(UL_UNFAIR_LOCK \| ULF_NO_ERRNO, &pr->__pdep_opaque1, 0);
	51	switch (-ret) {
	52	case 0:
	53	case ENOENT:
	54	return;
	55	default:
	56	PTHREAD_INTERNAL_CRASH(-ret, "__ulock_wake() failed");
	57	}
	58	}
	59
	60
c1f56ec9	61	PTHREAD_NOEXPORT_VARIANT
214d78a2 A	62	void
	63	pthread_dependency_fulfill_np(pthread_dependency_t pr, void value)
	64	{
	65	uint32_t old;
	66
	67	pr->__pdep_opaque2 = (uint64_t)(uintptr_t)value;
	68	old = os_atomic_xchg(&pr->__pdep_opaque1, PREREQUISITE_FULFILLED, release);
	69
	70	if (old != 0) _pthread_dependency_fulfill_slow(pr, old);
	71	}
	72
c1f56ec9	73	PTHREAD_NOEXPORT_VARIANT
214d78a2 A	74	void *
	75	pthread_dependency_wait_np(pthread_dependency_t *pr)
	76	{
	77	if (os_atomic_cmpxchg(&pr->__pdep_opaque1, 0, pr->__pdep_owner, relaxed)) {
	78	int ret;
	79	again:
	80	ret = __ulock_wait(UL_UNFAIR_LOCK \| ULF_NO_ERRNO, &pr->__pdep_opaque1,
	81	pr->__pdep_owner, 0);
	82	switch (-ret) {
	83	case EFAULT:
c6e5f90c	84	case EINTR:
214d78a2	85	case 0:
c6e5f90c	86	if (pr->__pdep_opaque1 == pr->__pdep_owner) goto again;
214d78a2 A	87	break;
	88	case EOWNERDEAD:
	89	PTHREAD_CLIENT_CRASH(pr->__pdep_owner, "Waiting on orphaned dependency");
	90	default:
	91	PTHREAD_CLIENT_CRASH(-ret, "__ulock_wait() failed");
	92	}
	93	}
	94
	95	uint32_t cur = os_atomic_load(&pr->__pdep_opaque1, acquire);
	96	if (cur == PREREQUISITE_FULFILLED) {
	97	return (void *)(uintptr_t)pr->__pdep_opaque2;
	98	}
	99	PTHREAD_CLIENT_CRASH(cur, "Corrupted pthread_dependency_t");
	100	}
	101
c1f56ec9 A	102	PTHREAD_NOEXPORT_VARIANT void*
	103	_pthread_atomic_xchg_ptr(void *p, void v)
	104	{
	105	return os_atomic_xchg(p, v, seq_cst);
	106	}
	107
	108	PTHREAD_NOEXPORT_VARIANT uint32_t
	109	_pthread_atomic_xchg_uint32_relaxed(uint32_t *p, uint32_t v)
	110	{
	111	return os_atomic_xchg(p, v, relaxed);
	112	}
	113
	114	#endif // !VARIANT_DYLD