[thirdparty/glibc.git] / sysdeps / unix / sysv / linux / x86_64 / pthread_rwlock_rdlock.S

/* Copyright (C) 2002-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>
#include <lowlevellock.h>
#include <lowlevelrwlock.h>
#include <pthread-errnos.h>
#include <kernel-features.h>
#include <stap-probe.h>

	.text

	.globl	__pthread_rwlock_rdlock
	.type	__pthread_rwlock_rdlock,@function
	.align	16
__pthread_rwlock_rdlock:
	cfi_startproc

	LIBC_PROBE (rdlock_entry, 1, %rdi)

	xorq	%r10, %r10

	/* Get the lock.  */
	movl	$1, %esi
	xorl	%eax, %eax
	LOCK
#if MUTEX == 0
	cmpxchgl %esi, (%rdi)
#else
	cmpxchgl %esi, MUTEX(%rdi)
#endif
	jnz	1f

2:	movl	WRITER(%rdi), %eax
	testl	%eax, %eax
	jne	14f
	cmpl	$0, WRITERS_QUEUED(%rdi)
	je	5f
	cmpl	$0, FLAGS(%rdi)
	je	5f

3:	incl	READERS_QUEUED(%rdi)
	je	4f

	movl	READERS_WAKEUP(%rdi), %edx

	LOCK
#if MUTEX == 0
	decl	(%rdi)
#else
	decl	MUTEX(%rdi)
#endif
	jne	10f

11:
#ifdef __ASSUME_PRIVATE_FUTEX
	movl	$FUTEX_PRIVATE_FLAG|FUTEX_WAIT, %esi
	xorl	PSHARED(%rdi), %esi
#else
# if FUTEX_WAIT == 0
	movl	PSHARED(%rdi), %esi
# else
	movl	$FUTEX_WAIT, %esi
	orl	PSHARED(%rdi), %esi
# endif
	xorl	%fs:PRIVATE_FUTEX, %esi
#endif
	addq	$READERS_WAKEUP, %rdi
	movl	$SYS_futex, %eax
	syscall

	subq	$READERS_WAKEUP, %rdi

	/* Reget the lock.  */
	movl	$1, %esi
	xorl	%eax, %eax
	LOCK
#if MUTEX == 0
	cmpxchgl %esi, (%rdi)
#else
	cmpxchgl %esi, MUTEX(%rdi)
#endif
	jnz	12f

13:	decl	READERS_QUEUED(%rdi)
	jmp	2b

5:	xorl	%edx, %edx
	incl	NR_READERS(%rdi)
	je	8f
9:	LOCK
#if MUTEX == 0
	decl	(%rdi)
#else
	decl	MUTEX(%rdi)
#endif
	jne	6f
7:

	movq	%rdx, %rax
	retq

1:	movl	PSHARED(%rdi), %esi
#if MUTEX != 0
	addq	$MUTEX, %rdi
#endif
	callq	__lll_lock_wait
#if MUTEX != 0
	subq	$MUTEX, %rdi
#endif
	jmp	2b

14:	cmpl	%fs:TID, %eax
	jne	3b
	/* Deadlock detected.  */
	movl	$EDEADLK, %edx
	jmp	9b

6:	movl	PSHARED(%rdi), %esi
#if MUTEX != 0
	addq	$MUTEX, %rdi
#endif
	callq	__lll_unlock_wake
#if MUTEX != 0
	subq	$MUTEX, %rdi
#endif
	jmp	7b

	/* Overflow.  */
8:	decl	NR_READERS(%rdi)
	movl	$EAGAIN, %edx
	jmp	9b

	/* Overflow.  */
4:	decl	READERS_QUEUED(%rdi)
	movl	$EAGAIN, %edx
	jmp	9b

10:	movl	PSHARED(%rdi), %esi
#if MUTEX != 0
	addq	$MUTEX, %rdi
#endif
	callq	__lll_unlock_wake
#if MUTEX != 0
	subq	$MUTEX, %rdi
#endif
	jmp	11b

12:	movl	PSHARED(%rdi), %esi
#if MUTEX == 0
	addq	$MUTEX, %rdi
#endif
	callq	__lll_lock_wait
#if MUTEX != 0
	subq	$MUTEX, %rdi
#endif
	jmp	13b
	cfi_endproc
	.size	__pthread_rwlock_rdlock,.-__pthread_rwlock_rdlock

strong_alias (__pthread_rwlock_rdlock, pthread_rwlock_rdlock)
hidden_def (__pthread_rwlock_rdlock)
Commit	Line	Data
d4697bc9	1	/* Copyright (C) 2002-2014 Free Software Foundation, Inc.
da49194d UD	2	This file is part of the GNU C Library.
	3	Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
	4
	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	16	License along with the GNU C Library; if not, see
59ba27a6 PE	17	<http://www.gnu.org/licenses/>. */
da49194d UD	18
da49194d UD	19	#include <sysdep.h>
e51deae7	20	#include <lowlevellock.h>
da49194d	21	#include <lowlevelrwlock.h>
326132db	22	#include <pthread-errnos.h>
50f1dec5	23	#include <kernel-features.h>
5acf7263	24	#include <stap-probe.h>
da49194d	25
da49194d UD	26	.text
	27
	28	.globl __pthread_rwlock_rdlock
	29	.type __pthread_rwlock_rdlock,@function
	30	.align 16
	31	__pthread_rwlock_rdlock:
1bc2b97e	32	cfi_startproc
5acf7263 RM	33
	34	LIBC_PROBE (rdlock_entry, 1, %rdi)
	35
da49194d UD	36	xorq %r10, %r10
	37
	38	/* Get the lock. */
	39	movl $1, %esi
3a226d33	40	xorl %eax, %eax
da49194d UD	41	LOCK
da49194d UD	42	#if MUTEX == 0
3a226d33	43	cmpxchgl %esi, (%rdi)
da49194d	44	#else
3a226d33	45	cmpxchgl %esi, MUTEX(%rdi)
da49194d	46	#endif
3a226d33	47	jnz 1f
da49194d	48
4ad0bbf4 UD	49	2: movl WRITER(%rdi), %eax
4ad0bbf4 UD	50	testl %eax, %eax
da49194d UD	51	jne 14f
	52	cmpl $0, WRITERS_QUEUED(%rdi)
	53	je 5f
	54	cmpl $0, FLAGS(%rdi)
	55	je 5f
	56
	57	3: incl READERS_QUEUED(%rdi)
	58	je 4f
	59
	60	movl READERS_WAKEUP(%rdi), %edx
	61
	62	LOCK
	63	#if MUTEX == 0
46a32546	64	decl (%rdi)
da49194d	65	#else
46a32546	66	decl MUTEX(%rdi)
da49194d UD	67	#endif
	68	jne 10f
	69
50f1dec5	70	11:
28635aca	71	#ifdef __ASSUME_PRIVATE_FUTEX
50f1dec5 UD	72	movl $FUTEX_PRIVATE_FLAG\|FUTEX_WAIT, %esi
50f1dec5 UD	73	xorl PSHARED(%rdi), %esi
ee618985	74	#else
50f1dec5 UD	75	# if FUTEX_WAIT == 0
	76	movl PSHARED(%rdi), %esi
	77	# else
ee618985	78	movl $FUTEX_WAIT, %esi
50f1dec5 UD	79	orl PSHARED(%rdi), %esi
	80	# endif
	81	xorl %fs:PRIVATE_FUTEX, %esi
ee618985	82	#endif
50f1dec5	83	addq $READERS_WAKEUP, %rdi
ee618985	84	movl $SYS_futex, %eax
da49194d UD	85	syscall
da49194d UD	86
46a32546	87	subq $READERS_WAKEUP, %rdi
da49194d UD	88
	89	/* Reget the lock. */
	90	movl $1, %esi
3a226d33	91	xorl %eax, %eax
da49194d UD	92	LOCK
da49194d UD	93	#if MUTEX == 0
3a226d33	94	cmpxchgl %esi, (%rdi)
da49194d	95	#else
3a226d33	96	cmpxchgl %esi, MUTEX(%rdi)
da49194d	97	#endif
3a226d33	98	jnz 12f
da49194d UD	99
	100	13: decl READERS_QUEUED(%rdi)
	101	jmp 2b
	102
ee618985	103	5: xorl %edx, %edx
da49194d UD	104	incl NR_READERS(%rdi)
	105	je 8f
	106	9: LOCK
	107	#if MUTEX == 0
	108	decl (%rdi)
	109	#else
	110	decl MUTEX(%rdi)
	111	#endif
	112	jne 6f
	113	7:
	114
92ed3daf	115	movq %rdx, %rax
da49194d UD	116	retq
da49194d UD	117
e51deae7	118	1: movl PSHARED(%rdi), %esi
da49194d UD	119	#if MUTEX != 0
	120	addq $MUTEX, %rdi
	121	#endif
e51deae7	122	callq __lll_lock_wait
da49194d UD	123	#if MUTEX != 0
	124	subq $MUTEX, %rdi
	125	#endif
	126	jmp 2b
	127
4ad0bbf4	128	14: cmpl %fs:TID, %eax
da49194d UD	129	jne 3b
da49194d UD	130	/* Deadlock detected. */
ee618985	131	movl $EDEADLK, %edx
da49194d UD	132	jmp 9b
da49194d UD	133
e51deae7	134	6: movl PSHARED(%rdi), %esi
da49194d UD	135	#if MUTEX != 0
	136	addq $MUTEX, %rdi
	137	#endif
e51deae7	138	callq __lll_unlock_wake
da49194d UD	139	#if MUTEX != 0
	140	subq $MUTEX, %rdi
	141	#endif
	142	jmp 7b
	143
	144	/* Overflow. */
	145	8: decl NR_READERS(%rdi)
ee618985	146	movl $EAGAIN, %edx
da49194d UD	147	jmp 9b
	148
	149	/* Overflow. */
	150	4: decl READERS_QUEUED(%rdi)
ee618985	151	movl $EAGAIN, %edx
da49194d UD	152	jmp 9b
da49194d UD	153
e51deae7	154	10: movl PSHARED(%rdi), %esi
da49194d UD	155	#if MUTEX != 0
	156	addq $MUTEX, %rdi
	157	#endif
e51deae7	158	callq __lll_unlock_wake
da49194d UD	159	#if MUTEX != 0
	160	subq $MUTEX, %rdi
	161	#endif
	162	jmp 11b
	163
e51deae7	164	12: movl PSHARED(%rdi), %esi
da49194d UD	165	#if MUTEX == 0
	166	addq $MUTEX, %rdi
	167	#endif
e51deae7	168	callq __lll_lock_wait
da49194d UD	169	#if MUTEX != 0
	170	subq $MUTEX, %rdi
	171	#endif
	172	jmp 13b
1bc2b97e	173	cfi_endproc
da49194d UD	174	.size __pthread_rwlock_rdlock,.-__pthread_rwlock_rdlock
da49194d UD	175
4d17e683 AS	176	strong_alias (__pthread_rwlock_rdlock, pthread_rwlock_rdlock)
4d17e683 AS	177	hidden_def (__pthread_rwlock_rdlock)