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Serban Constantinescue2104882013-09-26 11:37:10 +01001/*
Dan Albert6a918872014-08-05 20:53:31 +00002 * Copyright (C) 2013 The Android Open Source Project
Elliott Hughes54a74942014-01-03 16:40:37 -08003 * All rights reserved.
Serban Constantinescue2104882013-09-26 11:37:10 +01004 *
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
Christopher Ferrisc5d3a432019-09-25 17:50:36 -070029#include <platform/bionic/tls_defines.h>
Dan Albert6a918872014-08-05 20:53:31 +000030#include <private/bionic_asm.h>
Serban Constantinescue2104882013-09-26 11:37:10 +010031
Dan Albert6a918872014-08-05 20:53:31 +000032// This custom code preserves the return address across the system call.
33
34ENTRY(vfork)
dimitryfa432522017-10-25 13:07:45 +020035__BIONIC_WEAK_ASM_FOR_NATIVE_BRIDGE(vfork)
Dan Albert6a918872014-08-05 20:53:31 +000036 popq %rdi // Grab the return address.
Elliott Hughes5891abd2015-08-07 18:27:47 -070037
Josh Gao23032832020-05-07 17:02:19 -070038 // Set cached_pid_ to 0, vforked_ to 1, and stash the previous value.
39 mov %fs:0, %r8
40 mov (TLS_SLOT_THREAD_ID * 8)(%r8), %r8
41 movl 20(%r8), %r9d
42 movl $0x80000000, 20(%r8)
Elliott Hughes5891abd2015-08-07 18:27:47 -070043
Dan Albert6a918872014-08-05 20:53:31 +000044 movl $__NR_vfork, %eax
45 syscall
46 pushq %rdi // Restore the return address.
Josh Gao23032832020-05-07 17:02:19 -070047
48 test %eax, %eax
49 jz 1f
50
51 // rc != 0: restore the previous cached_pid_/vforked_ values.
52 movl %r9d, 20(%r8)
53
Dan Albert6a918872014-08-05 20:53:31 +000054 cmpq $-MAX_ERRNO, %rax
55 jb 1f
56 negl %eax
57 movl %eax, %edi
Elliott Hughes011e1112014-09-08 15:25:01 -070058 call __set_errno_internal
Dan Albert6a918872014-08-05 20:53:31 +0000591:
60 ret
61END(vfork)