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/* 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 <kernel-features.h>
#include <tcb-offsets.h>
#include <lowlevellock.h>
.comm __fork_generation, 4, 4
.text
.globl __pthread_once
.type __pthread_once,@function
.align 16
__pthread_once:
.LSTARTCODE:
cfi_startproc
#ifdef SHARED
cfi_personality(DW_EH_PE_pcrel | DW_EH_PE_sdata4 | DW_EH_PE_indirect,
DW.ref.__gcc_personality_v0)
cfi_lsda(DW_EH_PE_pcrel | DW_EH_PE_sdata4, .LexceptSTART)
#else
cfi_personality(DW_EH_PE_udata4, __gcc_personality_v0)
cfi_lsda(DW_EH_PE_udata4, .LexceptSTART)
#endif
testl $2, (%rdi)
jz 1f
xorl %eax, %eax
retq
/* Preserve the function pointer. */
1: pushq %rsi
cfi_adjust_cfa_offset(8)
xorq %r10, %r10
/* Not yet initialized or initialization in progress.
Get the fork generation counter now. */
6: movl (%rdi), %eax
5: movl %eax, %edx
testl $2, %eax
jnz 4f
andl $3, %edx
orl __fork_generation(%rip), %edx
orl $1, %edx
LOCK
cmpxchgl %edx, (%rdi)
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, %esi
#else
# if FUTEX_WAIT == 0
movl %fs:PRIVATE_FUTEX, %esi
# else
movl $FUTEX_WAIT, %esi
orl %fs:PRIVATE_FUTEX, %esi
# endif
#endif
movl $SYS_futex, %eax
syscall
jmp 6b
/* Preserve the pointer to the control variable. */
3: pushq %rdi
cfi_adjust_cfa_offset(8)
pushq %rdi
cfi_adjust_cfa_offset(8)
.LcleanupSTART:
callq *16(%rsp)
.LcleanupEND:
/* Get the control variable address back. */
popq %rdi
cfi_adjust_cfa_offset(-8)
/* Sucessful run of the initializer. Signal that we are done. */
LOCK
incl (%rdi)
addq $8, %rsp
cfi_adjust_cfa_offset(-8)
/* Wake up all other threads. */
movl $0x7fffffff, %edx
#ifdef __ASSUME_PRIVATE_FUTEX
movl $FUTEX_WAKE|FUTEX_PRIVATE_FLAG, %esi
#else
movl $FUTEX_WAKE, %esi
orl %fs:PRIVATE_FUTEX, %esi
#endif
movl $SYS_futex, %eax
syscall
4: addq $8, %rsp
cfi_adjust_cfa_offset(-8)
xorl %eax, %eax
retq
.size __pthread_once,.-__pthread_once
hidden_def (__pthread_once)
strong_alias (__pthread_once, pthread_once)
.type clear_once_control,@function
.align 16
clear_once_control:
cfi_adjust_cfa_offset(3 * 8)
movq (%rsp), %rdi
movq %rax, %r8
movl $0, (%rdi)
movl $0x7fffffff, %edx
#ifdef __ASSUME_PRIVATE_FUTEX
movl $FUTEX_WAKE|FUTEX_PRIVATE_FLAG, %esi
#else
movl $FUTEX_WAKE, %esi
orl %fs:PRIVATE_FUTEX, %esi
#endif
movl $SYS_futex, %eax
syscall
movq %r8, %rdi
.LcallUR:
call _Unwind_Resume@PLT
hlt
.LENDCODE:
cfi_endproc
.size clear_once_control,.-clear_once_control
.section .gcc_except_table,"a",@progbits
.LexceptSTART:
.byte DW_EH_PE_omit # @LPStart format
.byte DW_EH_PE_omit # @TType format
.byte DW_EH_PE_uleb128 # call-site format
.uleb128 .Lcstend-.Lcstbegin
.Lcstbegin:
.uleb128 .LcleanupSTART-.LSTARTCODE
.uleb128 .LcleanupEND-.LcleanupSTART
.uleb128 clear_once_control-.LSTARTCODE
.uleb128 0
.uleb128 .LcallUR-.LSTARTCODE
.uleb128 .LENDCODE-.LcallUR
.uleb128 0
.uleb128 0
.Lcstend:
#ifdef SHARED
.hidden DW.ref.__gcc_personality_v0
.weak DW.ref.__gcc_personality_v0
.section .gnu.linkonce.d.DW.ref.__gcc_personality_v0,"aw",@progbits
.align LP_SIZE
.type DW.ref.__gcc_personality_v0, @object
.size DW.ref.__gcc_personality_v0, LP_SIZE
DW.ref.__gcc_personality_v0:
ASM_ADDR __gcc_personality_v0
#endif
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