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/* Copyright (C) 2002-2013 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 <unwindbuf.h>
#include <sysdep.h>
#include <kernel-features.h>
#include <lowlevellock.h>
.comm __fork_generation, 4, 4
.text
.globl __pthread_once
.type __pthread_once,@function
.align 16
cfi_startproc
__pthread_once:
movl 4(%esp), %ecx
testl $2, (%ecx)
jz 1f
xorl %eax, %eax
ret
1: pushl %ebx
cfi_adjust_cfa_offset (4)
cfi_rel_offset (3, 0)
pushl %esi
cfi_adjust_cfa_offset (4)
cfi_rel_offset (6, 0)
movl %ecx, %ebx
xorl %esi, %esi
/* Not yet initialized or initialization in progress.
Get the fork generation counter now. */
6: movl (%ebx), %eax
#ifdef PIC
LOAD_PIC_REG(cx)
#endif
5: movl %eax, %edx
testl $2, %eax
jnz 4f
andl $3, %edx
#ifdef PIC
orl __fork_generation@GOTOFF(%ecx), %edx
#else
orl __fork_generation, %edx
#endif
orl $1, %edx
LOCK
cmpxchgl %edx, (%ebx)
jnz 5b
/* Check whether another thread already runs the initializer. */
testl $1, %eax
jz 3f /* No -> do it. */
/* Check whether the initializer execution was interrupted
by a fork. */
xorl %edx, %eax
testl $0xfffffffc, %eax
jnz 3f /* Different for generation -> run initializer. */
/* Somebody else got here first. Wait. */
#ifdef __ASSUME_PRIVATE_FUTEX
movl $FUTEX_WAIT|FUTEX_PRIVATE_FLAG, %ecx
#else
# if FUTEX_WAIT == 0
movl %gs:PRIVATE_FUTEX, %ecx
# else
movl $FUTEX_WAIT, %ecx
orl %gs:PRIVATE_FUTEX, %ecx
# endif
#endif
movl $SYS_futex, %eax
ENTER_KERNEL
jmp 6b
3: /* Call the initializer function after setting up the
cancellation handler. Note that it is not possible here
to use the unwind-based cleanup handling. This would require
that the user-provided function and all the code it calls
is compiled with exceptions. Unfortunately this cannot be
guaranteed. */
subl $UNWINDBUFSIZE+8, %esp
cfi_adjust_cfa_offset (UNWINDBUFSIZE+8)
movl %ecx, %ebx /* PIC register value. */
leal 8+UWJMPBUF(%esp), %eax
movl $0, 4(%esp)
movl %eax, (%esp)
call __sigsetjmp@PLT
testl %eax, %eax
jne 7f
leal 8(%esp), %eax
call HIDDEN_JUMPTARGET(__pthread_register_cancel)
/* Call the user-provided initialization function. */
call *24+UNWINDBUFSIZE(%esp)
/* Pop the cleanup handler. */
leal 8(%esp), %eax
call HIDDEN_JUMPTARGET(__pthread_unregister_cancel)
addl $UNWINDBUFSIZE+8, %esp
cfi_adjust_cfa_offset (-UNWINDBUFSIZE-8)
/* Sucessful run of the initializer. Signal that we are done. */
movl 12(%esp), %ebx
LOCK
addl $1, (%ebx)
/* Wake up all other threads. */
movl $0x7fffffff, %edx
#ifdef __ASSUME_PRIVATE_FUTEX
movl $FUTEX_WAKE|FUTEX_PRIVATE_FLAG, %ecx
#else
movl $FUTEX_WAKE, %ecx
orl %gs:PRIVATE_FUTEX, %ecx
#endif
movl $SYS_futex, %eax
ENTER_KERNEL
4: popl %esi
cfi_adjust_cfa_offset (-4)
cfi_restore (6)
popl %ebx
cfi_adjust_cfa_offset (-4)
cfi_restore (3)
xorl %eax, %eax
ret
7: /* __sigsetjmp returned for the second time. */
movl 20+UNWINDBUFSIZE(%esp), %ebx
cfi_adjust_cfa_offset (UNWINDBUFSIZE+16)
cfi_offset (3, -8)
cfi_offset (6, -12)
movl $0, (%ebx)
movl $0x7fffffff, %edx
#ifdef __ASSUME_PRIVATE_FUTEX
movl $FUTEX_WAKE|FUTEX_PRIVATE_FLAG, %ecx
#else
movl $FUTEX_WAKE, %ecx
orl %gs:PRIVATE_FUTEX, %ecx
#endif
movl $SYS_futex, %eax
ENTER_KERNEL
leal 8(%esp), %eax
call HIDDEN_JUMPTARGET (__pthread_unwind_next)
/* NOTREACHED */
hlt
cfi_endproc
.size __pthread_once,.-__pthread_once
hidden_def (__pthread_once)
strong_alias (__pthread_once, pthread_once)
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