platform_bionic/libc/arch-x86_64/bionic/vfork.S
Elliott Hughes d7831208b2 Fix assembler warnings.
clang complains if you define a symbol and _then_ make it weak, rather
than the other way round:

  /tmp/setjmp-c3c977.s:90:1: warning: sigsetjmp changed binding to STB_WEAK
  .weak sigsetjmp;
  ^

Test: treehugger
Change-Id: Iee6b0ea456bb2e92aea810ce45f171caabaa89d2
2024-01-23 22:06:19 +00:00

60 lines
2.1 KiB
ArmAsm

/*
* Copyright (C) 2013 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <platform/bionic/tls_defines.h>
#include <private/bionic_asm.h>
// This custom code preserves the return address across the system call.
ENTRY_WEAK_FOR_NATIVE_BRIDGE(vfork)
popq %rdi // Grab the return address.
// Set cached_pid_ to 0, vforked_ to 1, and stash the previous value.
mov %fs:0, %r8
mov (TLS_SLOT_THREAD_ID * 8)(%r8), %r8
movl 20(%r8), %r9d
movl $0x80000000, 20(%r8)
movl $__NR_vfork, %eax
syscall
pushq %rdi // Restore the return address.
test %eax, %eax
jz 1f
// rc != 0: restore the previous cached_pid_/vforked_ values.
movl %r9d, 20(%r8)
cmpq $-MAX_ERRNO, %rax
jb 1f
negl %eax
movl %eax, %edi
call __set_errno_internal
1:
ret
END(vfork)