Bring in FreeBSD 1.2.2.2. Properly unwind the stack when certain
[dragonfly.git] / lib / libc / i386 / gen / rfork_thread.S
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1/*-
2 * Copyright (c) 2000 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/i386/gen/rfork_thread.S,v 1.2.2.1 2001/02/07 00:12:45 peter Exp $
02b6afea 27 * $DragonFly: src/lib/libc/i386/gen/rfork_thread.S,v 1.3 2004/04/05 05:31:58 dillon Exp $
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28 */
29
30/*
31 * With thanks to John Dyson for the original version of this.
32 */
33
34#include <SYS.h>
35
36/*
37 * 8 12 16 20
38 * rfork_thread(flags, stack_addr, start_fnc, start_arg);
39 *
40 * flags: Flags to rfork system call. See rfork(2).
41 * stack_addr: Top of stack for thread.
42 * start_fnc: Address of thread function to call in child.
43 * start_arg: Argument to pass to the thread function in child.
44 */
45
46ENTRY(rfork_thread)
47 pushl %ebp
48 movl %esp, %ebp
49 pushl %esi
50
51 /*
52 * Push thread info onto the new thread's stack
53 */
54 movl 12(%ebp), %esi # get stack addr
55
56 subl $4, %esi
57 movl 20(%ebp), %eax # get start argument
58 movl %eax, (%esi)
59
60 subl $4, %esi
61 movl 16(%ebp), %eax # get start thread address
62 movl %eax, (%esi)
63
64 /*
65 * Prepare and execute the thread creation syscall
66 */
67 pushl 8(%ebp)
68 pushl $0
69 leal SYS_rfork, %eax
70 KERNCALL
71 jb 2f
72
73 /*
74 * Check to see if we are in the parent or child
75 */
76 cmpl $0, %edx
77 jnz 1f
78 addl $8, %esp
79 popl %esi
80 movl %ebp, %esp
81 popl %ebp
82 ret
83 .p2align 2
84
85 /*
86 * If we are in the child (new thread), then
87 * set-up the call to the internal subroutine. If it
88 * returns, then call __exit.
89 */
901:
91 movl %esi,%esp
92 popl %eax
93 call *%eax
94 addl $4, %esp
95
96 /*
97 * Exit system call
98 */
99 pushl %eax
100 pushl $0
101#ifdef SYS_exit
102 leal SYS_exit, %eax
103#else
104 leal SYS_sys_exit, %eax
105#endif
106 KERNCALL
107
108 /*
109 * Branch here if the thread creation fails:
110 */
1112:
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112 addl $8,%esp
113 popl %esi
114 movl %ebp,%esp
115 popl %ebp
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116 PIC_PROLOGUE
117 jmp PIC_PLT(HIDENAME(cerror))