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glibc/nptl/sysdeps/unix/sysv/linux/i386/pthread_once.S
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/* Copyright (C) 2002, 2003 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, write to the Free | |
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
02111-1307 USA. */ | |
#include <unwindbuf.h> | |
#include <sysdep.h> | |
#ifndef UP | |
# define LOCK lock | |
#else | |
# define LOCK | |
#endif | |
#define SYS_futex 240 | |
#define FUTEX_WAKE 1 | |
.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 | |
call __i686.get_pc_thunk.cx | |
addl $_GLOBAL_OFFSET_TABLE_, %ecx | |
#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. */ | |
movl %esi, %ecx /* movl $FUTEX_WAIT, %ecx */ | |
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 | |
jne 7f | |
leal 8(%esp), %eax | |
call __pthread_register_cancel | |
/* Call the user-provided initialization function. */ | |
call *24+UNWINDBUFSIZE(%esp) | |
/* Pop the cleanup handler. */ | |
leal 8(%esp), %eax | |
call __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 | |
movl $FUTEX_WAKE, %ecx | |
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 | |
movl $FUTEX_WAKE, %ecx | |
movl $SYS_futex, %eax | |
ENTER_KERNEL | |
leal 8(%esp), %eax | |
call __pthread_unwind_next /* Note: no @PLT. */ | |
/* NOTREACHED */ | |
hlt | |
cfi_endproc | |
.size __pthread_once,.-__pthread_once | |
.globl __pthread_once_internal | |
__pthread_once_internal = __pthread_once | |
.globl pthread_once | |
pthread_once = __pthread_once | |
#ifdef PIC | |
.section .gnu.linkonce.t.__i686.get_pc_thunk.cx,"ax",@progbits | |
.globl __i686.get_pc_thunk.cx | |
.hidden __i686.get_pc_thunk.cx | |
.type __i686.get_pc_thunk.cx,@function | |
__i686.get_pc_thunk.cx: | |
movl (%esp), %ecx; | |
ret | |
.size __i686.get_pc_thunk.cx,.-__i686.get_pc_thunk.cx | |
#endif |