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glibc/sysdeps/unix/sysv/linux/x86_64/cancellation.S
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/* Copyright (C) 2009-2016 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Ulrich Drepper <drepper@redhat.com>, 2009. | |
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 <tcb-offsets.h> | |
#include <kernel-features.h> | |
#include "lowlevellock.h" | |
#if IS_IN (libpthread) | |
# if defined SHARED && !defined NO_HIDDEN | |
# define __pthread_unwind __GI___pthread_unwind | |
# endif | |
#else | |
# ifndef SHARED | |
.weak __pthread_unwind | |
# endif | |
#endif | |
#ifdef __ASSUME_PRIVATE_FUTEX | |
# define LOAD_PRIVATE_FUTEX_WAIT(reg) \ | |
movl $(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg | |
#else | |
# if FUTEX_WAIT == 0 | |
# define LOAD_PRIVATE_FUTEX_WAIT(reg) \ | |
movl %fs:PRIVATE_FUTEX, reg | |
# else | |
# define LOAD_PRIVATE_FUTEX_WAIT(reg) \ | |
movl %fs:PRIVATE_FUTEX, reg ; \ | |
orl $FUTEX_WAIT, reg | |
# endif | |
#endif | |
/* It is crucial that the functions in this file don't modify registers | |
other than %rax and %r11. The syscall wrapper code depends on this | |
because it doesn't explicitly save the other registers which hold | |
relevant values. */ | |
.text | |
.hidden __pthread_enable_asynccancel | |
ENTRY(__pthread_enable_asynccancel) | |
movl %fs:CANCELHANDLING, %eax | |
2: movl %eax, %r11d | |
orl $TCB_CANCELTYPE_BITMASK, %r11d | |
cmpl %eax, %r11d | |
je 1f | |
lock | |
cmpxchgl %r11d, %fs:CANCELHANDLING | |
jnz 2b | |
andl $(TCB_CANCELSTATE_BITMASK|TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK|TCB_EXITING_BITMASK|TCB_CANCEL_RESTMASK|TCB_TERMINATED_BITMASK), %r11d | |
cmpl $(TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK), %r11d | |
je 3f | |
1: ret | |
3: subq $8, %rsp | |
cfi_adjust_cfa_offset(8) | |
LP_OP(mov) $TCB_PTHREAD_CANCELED, %fs:RESULT | |
lock | |
orl $TCB_EXITING_BITMASK, %fs:CANCELHANDLING | |
mov %fs:CLEANUP_JMP_BUF, %RDI_LP | |
call JUMPTARGET(__pthread_unwind) | |
hlt | |
END(__pthread_enable_asynccancel) | |
.hidden __pthread_disable_asynccancel | |
ENTRY(__pthread_disable_asynccancel) | |
testl $TCB_CANCELTYPE_BITMASK, %edi | |
jnz 1f | |
movl %fs:CANCELHANDLING, %eax | |
2: movl %eax, %r11d | |
andl $~TCB_CANCELTYPE_BITMASK, %r11d | |
lock | |
cmpxchgl %r11d, %fs:CANCELHANDLING | |
jnz 2b | |
movl %r11d, %eax | |
3: andl $(TCB_CANCELING_BITMASK|TCB_CANCELED_BITMASK), %eax | |
cmpl $TCB_CANCELING_BITMASK, %eax | |
je 4f | |
1: ret | |
/* Performance doesn't matter in this loop. We will | |
delay until the thread is canceled. And we will unlikely | |
enter the loop twice. */ | |
4: mov %fs:0, %RDI_LP | |
movl $__NR_futex, %eax | |
xorq %r10, %r10 | |
addq $CANCELHANDLING, %rdi | |
LOAD_PRIVATE_FUTEX_WAIT (%esi) | |
syscall | |
movl %fs:CANCELHANDLING, %eax | |
jmp 3b | |
END(__pthread_disable_asynccancel) |