add header glue
[dragonfly.git] / lib / libc / amd64 / sys / getcontext.S
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1/*-
2 * Copyright (c) 2003 Peter Wemm <peter@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * 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 * $FreeBSD: src/lib/libc/amd64/sys/getcontext.S,v 1.2 2003/09/04 00:31:45 peter Exp $
27 * $DragonFly: src/lib/libc/amd64/sys/Attic/getcontext.S,v 1.1 2004/02/02 05:43:14 dillon Exp $
28 */
29
30#include <machine/asm.h>
31#include <SYS.h>
32
33/*
34 * This has to be magic to handle the multiple returns.
35 * Otherwise, the setcontext() syscall will return here and we'll
36 * pop off the return address and go to the *setcontext* call.
37 */
38 .weak _getcontext
39 .set _getcontext,__sys_getcontext
40 .weak getcontext
41 .set getcontext,__sys_getcontext
42ENTRY(__sys_getcontext)
43 movq (%rsp),%rsi /* save getcontext return address */
44 mov $SYS_getcontext,%rax
45 KERNCALL
46 jb 1f
47 addq $8,%rsp /* remove stale (setcontext) return address */
48 jmp *%rsi /* restore return address */
491:
50#ifdef PIC
51 movq PIC_GOT(HIDENAME(cerror)),%rdx
52 jmp *%rdx
53#else
54 jmp HIDENAME(cerror)
55#endif