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Apply same basic fix for getcontext(2) as for i386. Store the return

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value for getcontext() in a preserved register rather than on the stack.
The second time around, the stack value would likely have changed so we
can't depend on it for the return value.
This commit is contained in:
Peter Wemm 2003-09-04 00:29:12 +00:00
parent c95f58c2f1
commit 294b146f2a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=119726
2 changed files with 56 additions and 2 deletions
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4
lib/libc/amd64/sys/Makefile.inc
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@ -1,8 +1,8 @@
# from: Makefile.inc,v 1.1 1993/09/03 19:04:23 jtc Exp
# $FreeBSD$
MDASM= vfork.S brk.S cerror.S exect.S pipe.S ptrace.S reboot.S sbrk.S \
setlogin.S sigreturn.S
MDASM= vfork.S brk.S cerror.S exect.S getcontext.S pipe.S ptrace.S \
reboot.S sbrk.S setlogin.S sigreturn.S
# Don't generate default code for these syscalls:
NOASM= break.o exit.o ftruncate.o getdomainname.o getlogin.o \

54
lib/libc/amd64/sys/getcontext.S Normal file
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@ -0,0 +1,54 @@
/*-
* Copyright (c) 2003 Peter Wemm <peter@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
#include <SYS.h>
/*
* This has to be magic to handle the multiple returns.
* Otherwise, the setcontext() syscall will return here and we'll
* pop off the return address and go to the *setcontext* call.
*/
.weak _getcontext
.set _getcontext,__sys_getcontext
.weak getcontext
.set getcontext,__sys_getcontext
ENTRY(__sys_getcontext)
movq (%rsp),%rsi /* save getcontext return address */
mov $SYS_getcontext,%rax
KERNCALL
jb 1f
addl $8,%rsp /* remove stale (setcontext) return address */
jmp *%rsi /* restore return address */
1:
#ifdef PIC
movq PIC_GOT(HIDENAME(cerror)),%rdx
jmp *%rdx
#else
jmp HIDENAME(cerror)
#endif