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/* Install given context.
Copyright (C) 2002-2018 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, see
<http://www.gnu.org/licenses/>. */
#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
cfi_adjust_cfa_offset(8)
/* Set the signal mask with
rt_sigprocmask (SIG_SETMASK, mask, NULL, _NSIG/8). */
leaq oSIGMASK(%rdi), %rsi
xorl %edx, %edx
movl $SIG_SETMASK, %edi
movl $_NSIG8,%r10d
movl $__NR_rt_sigprocmask, %eax
syscall
/* Pop the pointer into RDX. The choice is arbitrary, but
leaving RDI and RSI available for use later can avoid
shuffling values. */
popq %rdx
cfi_adjust_cfa_offset(-8)
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(%rdx), %rcx
fldenv (%rcx)
ldmxcsr oMXCSR(%rdx)
/* Load the new stack pointer, the preserved registers and
registers used for passing args. */
cfi_def_cfa(%rdx, 0)
cfi_offset(%rbx,oRBX)
cfi_offset(%rbp,oRBP)
cfi_offset(%r12,oR12)
cfi_offset(%r13,oR13)
cfi_offset(%r14,oR14)
cfi_offset(%r15,oR15)
cfi_offset(%rsp,oRSP)
cfi_offset(%rip,oRIP)
movq oRSP(%rdx), %rsp
movq oRBX(%rdx), %rbx
movq oRBP(%rdx), %rbp
movq oR12(%rdx), %r12
movq oR13(%rdx), %r13
movq oR14(%rdx), %r14
movq oR15(%rdx), %r15
/* The following ret should return to the address set with
getcontext. Therefore push the address on the stack. */
movq oRIP(%rdx), %rcx
pushq %rcx
movq oRSI(%rdx), %rsi
movq oRDI(%rdx), %rdi
movq oRCX(%rdx), %rcx
movq oR8(%rdx), %r8
movq oR9(%rdx), %r9
/* Setup finally %rdx. */
movq oRDX(%rdx), %rdx
/* End FDE here, we fall into another context. */
cfi_endproc
cfi_startproc
/* Clear rax to indicate success. */
xorl %eax, %eax
ret
PSEUDO_END(__setcontext)
weak_alias (__setcontext, setcontext)
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