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/* Install given context.
Copyright (C) 2001-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2001.
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
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include "ucontext_i.h"
ENTRY(__setcontext)
/* Load address of the context data structure. */
movl 4(%esp), %eax
/* Get the current signal mask. Note that we preserve EBX in case
the system call fails and we return from the function with an
error. */
pushl %ebx
cfi_adjust_cfa_offset (4)
xorl %edx, %edx
leal oSIGMASK(%eax), %ecx
movl $SIG_SETMASK, %ebx
cfi_rel_offset (ebx, 0)
movl $__NR_sigprocmask, %eax
ENTER_KERNEL
popl %ebx
cfi_adjust_cfa_offset (-4)
cfi_restore (ebx)
cmpl $-4095, %eax /* Check %eax for error. */
jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */
/* EAX was modified, reload it. */
movl 4(%esp), %eax
/* Restore the floating-point context. Not the registers, only the
rest. */
movl oFPREGS(%eax), %ecx
fldenv (%ecx)
/* Restore the FS segment register. We don't touch the GS register
since it is used for threads. */
movl oFS(%eax), %ecx
movw %cx, %fs
/* Fetch the address to return to. */
movl oEIP(%eax), %ecx
/* Load the new stack pointer. */
cfi_def_cfa (eax, 0)
cfi_offset (edi, oEDI)
cfi_offset (esi, oESI)
cfi_offset (ebp, oEBP)
cfi_offset (ebx, oEBX)
cfi_offset (edx, oEDX)
cfi_offset (ecx, oECX)
movl oESP(%eax), %esp
/* Push the return address on the new stack so we can return there. */
pushl %ecx
/* Load the values of all the 32-bit registers (except ESP).
Since we are loading from EAX, it must be last. */
movl oEDI(%eax), %edi
movl oESI(%eax), %esi
movl oEBP(%eax), %ebp
movl oEBX(%eax), %ebx
movl oEDX(%eax), %edx
movl oECX(%eax), %ecx
movl oEAX(%eax), %eax
/* End FDE here, we fall into another context. */
cfi_endproc
cfi_startproc
/* The following 'ret' will pop the address of the code and jump
to it. */
ret
PSEUDO_END(__setcontext)
libc_hidden_def (__setcontext)
weak_alias (__setcontext, setcontext)
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