| /* 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 <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) |
