xref: /dragonfly/lib/libc/x86_64/gen/rfork_thread.S (revision 8b927cb7b72266b97393ee565d882d7fddfa4375) 
1/*-
2 * Copyright (c) 2000 Peter Wemm <peter@FreeBSD.org>
3 * Copyright (c) 2003 Alan L. Cox <alc@cs.rice.edu>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD: src/lib/libc/amd64/gen/rfork_thread.S,v 1.2 2008/11/02 01:10:54 peter Exp $
28 */
29
30#include <machine/asm.h>
31
32/*
33 * With thanks to John Dyson for the original version of this.
34 */
35
36#include <SYS.h>
37
38/*
39 *              %edi   %rsi        %rdx       %rcx
40 * rfork_thread(flags, stack_addr, start_fnc, start_arg);
41 *
42 * flags:           Flags to rfork system call.  See rfork(2).
43 * stack_addr:                Top of stack for thread.
44 * start_fnc:                 Address of thread function to call in child.
45 * start_arg:                 Argument to pass to the thread function in child.
46 */
47
48ENTRY(rfork_thread)
49          pushq     %rbx
50          pushq     %r12
51          movq      %rdx, %rbx
52          movq      %rcx, %r12
53
54          /*
55           * Prepare and execute the thread creation syscall
56           */
57          movq      $SYS_rfork, %rax
58          KERNCALL
59          jb        2f
60
61          /*
62           * Check to see if we are in the parent or child
63           */
64          cmpl      $0, %edx
65          jnz       1f
66          popq      %r12
67          popq      %rbx
68          ret
69
70          /*
71           * If we are in the child (new thread), then
72           * set-up the call to the internal subroutine.  If it
73           * returns, then call __exit.
74           */
751:
76          movq      %rsi, %rsp
77          movq      %r12, %rdi
78          call      *%rbx
79          movl      %eax, %edi
80
81          /*
82           * Exit system call
83           */
84#ifdef SYS_exit
85          movq      $SYS_exit, %rax
86#else
87          movq      $SYS_sys_exit, %rax
88#endif
89          KERNCALL
90
91          /*
92           * Branch here if the thread creation fails:
93           */
942:
95          popq      %r12
96          popq      %rbx
97#ifdef PIC
98          movq      PIC_GOT(HIDENAME(cerror)), %rdx
99          jmp       *%rdx
100#else
101          jmp       HIDENAME(cerror)
102#endif
103END(rfork_thread)
104
105          .section .note.GNU-stack,"",%progbits
106