glibc/sysdeps/unix/sysv/linux/x86_64/setcontext.S

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/* Install given context.
Copyright (C) 2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Andreas Jaeger <aj@suse.de>, 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 <sysdep.h>
#include "ucontext_i.h"
/* int __setcontext (const ucontext_t *ucp)
Restores the machine context in UCP and thereby resumes execution
in that context.
This implementation is intended to be used for *synchronous* context
switches only. Therefore, it does not have to restore anything
other than the PRESERVED state. */
ENTRY(__setcontext)
/* Save argument since syscall will destroy it. */
pushq %rdi
/* Set the signal mask with
rt_sigprocmask (SIG_SETMASK, mask, NULL, _NSIG/8). */
leaq oSIGMASK(%rdi), %rsi
xorq %rdx, %rdx
movq $SIG_SETMASK, %rdi
movq $_NSIG8,%r10
movq $__NR_rt_sigprocmask, %rax
syscall
popq %rdi /* Reload %rdi, adjust stack. */
cmpq $-4095, %rax /* Check %rax for error. */
jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */
/* Restore the floating-point context. Not the registers, only the
rest. */
movq oFPREGS(%rdi), %rcx
fldenv (%rcx)
ldmxcsr oMXCSR(%rdi)
/* Load the new stack pointer and the preserved registers. */
movq oRSP(%rdi), %rsp
movq oRBX(%rdi), %rbx
movq oRBP(%rdi), %rbp
movq oR12(%rdi), %r12
movq oR13(%rdi), %r13
movq oR14(%rdi), %r14
movq oR15(%rdi), %r15
/* The following ret should return to the address set with
getcontext. Therefore push the address on the stack. */
movq oRIP(%rdi), %rcx
pushq %rcx
/* Clear rax to indicate success. */
xorq %rax, %rax
L(pseudo_end):
ret
PSEUDO_END(__setcontext)
weak_alias(__setcontext, setcontext)