getcontext.S revision 258447 
1280182Sjfv/*-
2280182Sjfv * Copyright (c) 2003 Peter Wemm <peter@FreeBSD.org>
3319182Sngie * All rights reserved.
4280182Sjfv *
5280182Sjfv * Redistribution and use in source and binary forms, with or without
6294444Sbdrewery * modification, are permitted provided that the following conditions
7280182Sjfv * are met:
8320897Serj * 1. Redistributions of source code must retain the above copyright
9320897Serj *    notice, this list of conditions and the following disclaimer.
10280182Sjfv * 2. Redistributions in binary form must reproduce the above copyright
11280182Sjfv *    notice, this list of conditions and the following disclaimer in the
12280182Sjfv *    documentation and/or other materials provided with the distribution.
13282290Serj *
14319182Sngie * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15280182Sjfv * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16280182Sjfv * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <machine/asm.h>
28__FBSDID("$FreeBSD: head/lib/libc/amd64/sys/getcontext.S 258447 2013-11-21 21:25:58Z andreast $");
29
30#include <SYS.h>
31
32/*
33 * This has to be magic to handle the multiple returns.
34 * Otherwise, the setcontext() syscall will return here and we'll
35 * pop off the return address and go to the *setcontext* call.
36 */
37	WEAK_REFERENCE(__sys_getcontext, _getcontext)
38	WEAK_REFERENCE(__sys_getcontext, getcontext)
39ENTRY(__sys_getcontext)
40	movq	(%rsp),%rsi	/* save getcontext return address */
41	mov	$SYS_getcontext,%rax
42	KERNCALL
43	jb	HIDENAME(cerror)
44	addq	$8,%rsp		/* remove stale (setcontext) return address */
45	jmp	*%rsi		/* restore return address */
46END(__sys_getcontext)
47
48	.section .note.GNU-stack,"",%progbits
49