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authorFlorian Fainelli <florian@openwrt.org>2013-01-09 16:17:21 +0100
committerBernhard Reutner-Fischer <rep.dot.nop@gmail.com>2013-01-10 10:56:19 +0100
commita8dc90eaaa5e6474beac828558d969b1aafee4af (patch)
treeed22c27193dcc91697f6b8782da9a9abd08d42b1 /libc/sysdeps/linux/i386/getcontext.S
parentdf3a5fcc8d1c3402289375c92df705e978fab58d (diff)
libc: add {get,set,swap,make}context user context manipulation functions
Add the obsolescent SUSv3 family of user context manipulating functions for arm, i386, mips, x86_64. Signed-off-by: Timon ter Braak <timonterbraak@gmail.com> Signed-off-by: Florian Fainelli <florian@openwrt.org> Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com> Signed-off-by: Natanael Copa <ncopa@alpinelinux.org> Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Diffstat (limited to 'libc/sysdeps/linux/i386/getcontext.S')
-rw-r--r--libc/sysdeps/linux/i386/getcontext.S84
1 files changed, 84 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/i386/getcontext.S b/libc/sysdeps/linux/i386/getcontext.S
new file mode 100644
index 000000000..3221b597c
--- /dev/null
+++ b/libc/sysdeps/linux/i386/getcontext.S
@@ -0,0 +1,84 @@
+/* Save current context.
+ Copyright (C) 2001-2012 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
+ <http://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)
+
+ /* We have separate floating-point register content memory on the
+ stack. We use the __fpregs_mem block in the context. Set the
+ links up correctly. */
+ leal oFPREGSMEM(%eax), %ecx
+ movl %ecx, oFPREGS(%eax)
+ /* 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. */
+ pushl %ebx
+ cfi_adjust_cfa_offset (4)
+ cfi_rel_offset (ebx, 0)
+ leal oSIGMASK(%eax), %edx
+ xorl %ecx, %ecx
+ movl $SIG_BLOCK, %ebx
+ 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. */
+
+ /* All done, return 0 for success. */
+ xorl %eax, %eax
+L(pseudo_end):
+ ret
+PSEUDO_END(__getcontext)
+
+weak_alias (__getcontext, getcontext)