glibc/sysdeps/mach/hurd/i386/getcontext.S
Thomas Schwinge a678c13b8f hurd: Add getcontext, makecontext, setcontext, swapcontext
Adapted from the Linux x86 functions.

Not thoroughly tested, but manual testing as well as glibc tests look fine, and
manual -lpthread testing also looks fine (within the given bounds for a new
stack to be used with makecontext).

This has also been in use in Debian since 2013.
2019-12-29 16:54:08 +01:00

75 lines
2.2 KiB
ArmAsm

/* Save current context.
Copyright (C) 2001-2019 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(__getcontext)
/* Load address of the context data structure. */
movl 4(%esp), %eax
/* Return value of getcontext. EAX is the only register whose
value is not preserved. */
movl $0, oEAX(%eax)
/* Save the 32-bit register values and the return address. */
movl %ecx, oECX(%eax)
movl %edx, oEDX(%eax)
movl %edi, oEDI(%eax)
movl %esi, oESI(%eax)
movl %ebp, oEBP(%eax)
movl (%esp), %ecx
movl %ecx, oEIP(%eax)
leal 4(%esp), %ecx /* Exclude the return address. */
movl %ecx, oESP(%eax)
movl %ebx, oEBX(%eax)
/* Save the FS segment register. We don't touch the GS register
since it is used for threads. */
xorl %edx, %edx
movw %fs, %dx
movl %edx, oFS(%eax)
leal oFPREGS(%eax), %ecx
/* Save the floating-point context. */
fnstenv (%ecx)
/* And load it right back since the processor changes the mask.
Intel thought this opcode to be used in interrupt handlers which
would block all exceptions. */
fldenv (%ecx)
/* Save the current signal mask. */
subl $12, %esp
cfi_adjust_cfa_offset (12)
leal oSIGMASK(%eax), %eax
movl %eax, 8(%esp)
movl $0, 4(%esp)
movl $SIG_BLOCK, (%esp)
call HIDDEN_JUMPTARGET (__sigprocmask)
addl $12, %esp
cfi_adjust_cfa_offset (-12)
/* Propagate %eax (and errno, in case). */
ret
PSEUDO_END(__getcontext)
weak_alias (__getcontext, getcontext)