xref: /freebsd/lib/libsys/amd64/getcontext.S (revision 8269e7673cf033aba67dab8264fe719920c70f87)
1*8269e767SBrooks Davis/*-
2*8269e767SBrooks Davis * Copyright (c) 2003 Peter Wemm <peter@FreeBSD.org>
3*8269e767SBrooks Davis * All rights reserved.
4*8269e767SBrooks Davis *
5*8269e767SBrooks Davis * Redistribution and use in source and binary forms, with or without
6*8269e767SBrooks Davis * modification, are permitted provided that the following conditions
7*8269e767SBrooks Davis * are met:
8*8269e767SBrooks Davis * 1. Redistributions of source code must retain the above copyright
9*8269e767SBrooks Davis *    notice, this list of conditions and the following disclaimer.
10*8269e767SBrooks Davis * 2. Redistributions in binary form must reproduce the above copyright
11*8269e767SBrooks Davis *    notice, this list of conditions and the following disclaimer in the
12*8269e767SBrooks Davis *    documentation and/or other materials provided with the distribution.
13*8269e767SBrooks Davis *
14*8269e767SBrooks Davis * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15*8269e767SBrooks Davis * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16*8269e767SBrooks Davis * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17*8269e767SBrooks Davis * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18*8269e767SBrooks Davis * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19*8269e767SBrooks Davis * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20*8269e767SBrooks Davis * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21*8269e767SBrooks Davis * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22*8269e767SBrooks Davis * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23*8269e767SBrooks Davis * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24*8269e767SBrooks Davis * SUCH DAMAGE.
25*8269e767SBrooks Davis */
26*8269e767SBrooks Davis
27*8269e767SBrooks Davis#include <machine/asm.h>
28*8269e767SBrooks Davis#include <SYS.h>
29*8269e767SBrooks Davis
30*8269e767SBrooks Davis/*
31*8269e767SBrooks Davis * This has to be magic to handle the multiple returns.
32*8269e767SBrooks Davis * Otherwise, the setcontext() syscall will return here and we'll
33*8269e767SBrooks Davis * pop off the return address and go to the *setcontext* call.
34*8269e767SBrooks Davis */
35*8269e767SBrooks Davis	WEAK_REFERENCE(__sys_getcontext, _getcontext)
36*8269e767SBrooks Davis	WEAK_REFERENCE(__sys_getcontext, getcontext)
37*8269e767SBrooks DavisENTRY(__sys_getcontext)
38*8269e767SBrooks Davis	movq	(%rsp),%rsi	/* save getcontext return address */
39*8269e767SBrooks Davis	_SYSCALL(getcontext)
40*8269e767SBrooks Davis	jb	HIDENAME(cerror)
41*8269e767SBrooks Davis	addq	$8,%rsp		/* remove stale (setcontext) return address */
42*8269e767SBrooks Davis	jmp	*%rsi		/* restore return address */
43*8269e767SBrooks DavisEND(__sys_getcontext)
44*8269e767SBrooks Davis
45*8269e767SBrooks Davis	.section .note.GNU-stack,"",%progbits
46