1/*
2 * Copyright (C) 2015 The Android Open Source Project
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 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <platform/bionic/tls_defines.h>
30#include <private/bionic_asm.h>
31
32ENTRY(vfork)
33__BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(vfork)
34    // r3 = &__get_tls()[TLS_SLOT_THREAD_ID]
35    mrc     p15, 0, r3, c13, c0, 3
36    ldr     r3, [r3, #(TLS_SLOT_THREAD_ID * 4)]
37
38    // Set cached_pid_ to 0, vforked_ to 1, and stash the previous value.
39    mov     r0, #0x80000000
40    ldr     r1, [r3, #12]
41    str     r0, [r3, #12]
42
43    mov     ip, r7
44    ldr     r7, =__NR_vfork
45    swi     #0
46    mov     r7, ip
47
48    teq     r0, #0
49    bxeq    lr
50
51    // rc != 0: reset cached_pid_ and vforked_.
52    str     r1, [r3, #12]
53    cmn     r0, #(MAX_ERRNO + 1)
54
55    bxls    lr
56    neg     r0, r0
57    b       __set_errno_internal
58END(vfork)
59