diff options
Diffstat (limited to 'libpthread/nptl/sysdeps/unix/sysv/linux/i386/pthread_once.S')
| -rw-r--r-- | libpthread/nptl/sysdeps/unix/sysv/linux/i386/pthread_once.S | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/libpthread/nptl/sysdeps/unix/sysv/linux/i386/pthread_once.S b/libpthread/nptl/sysdeps/unix/sysv/linux/i386/pthread_once.S new file mode 100644 index 000000000..409df15f8 --- /dev/null +++ b/libpthread/nptl/sysdeps/unix/sysv/linux/i386/pthread_once.S @@ -0,0 +1,196 @@ +/* Copyright (C) 2002, 2003, 2007 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> +#include <bits/kernel-features.h> +#include <lowlevellock.h> +#include <tls.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__ + call __x86.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. */ +#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 + + .globl __pthread_once_internal +__pthread_once_internal = __pthread_once + + .globl pthread_once +pthread_once = __pthread_once + + +#ifdef __PIC__ + .section .gnu.linkonce.t.__x86.get_pc_thunk.cx,"ax",@progbits + .globl __x86.get_pc_thunk.cx + .hidden __x86.get_pc_thunk.cx + .type __x86.get_pc_thunk.cx,@function +__x86.get_pc_thunk.cx: + movl (%esp), %ecx; + ret + .size __x86.get_pc_thunk.cx,.-__x86.get_pc_thunk.cx +#endif |