platform_bionic/libc/arch-x86/bionic/__bionic_clone.S
Elliott Hughes 011e111d29 Ensure __set_errno is still visible on LP32.
The use of the .hidden directive to avoid going via the PLT for
__set_errno had the side-effect of actually making __set_errno
hidden (which is odd because assembler directives don't usually
affect symbols defined in a different file --- you can't even
create a weak reference to a symbol that's defined in a different
file).

This change switches the system call stubs over to a new always-hidden
__set_errno_internal and has a visible __set_errno on LP32 just for
binary compatibility with old NDK apps.

(cherry-pick of 7efad83d430f4d824f2aaa75edea5106f6ff8aae.)

Bug: 17423135
Change-Id: I6b6d7a05dda85f923d22e5ffd169a91e23499b7b
2014-09-08 16:46:50 -07:00

53 lines
1.5 KiB
ArmAsm

#include <private/bionic_asm.h>
// pid_t __bionic_clone(int flags, void* child_stack, pid_t* parent_tid, void* tls, pid_t* child_tid, int (*fn)(void*), void* arg);
ENTRY(__bionic_clone)
pushl %ebx
pushl %esi
pushl %edi
# Load system call arguments into registers.
movl 16(%esp), %ebx # flags
movl 20(%esp), %ecx # child_stack
movl 24(%esp), %edx # parent_tid
movl 28(%esp), %esi # tls
movl 32(%esp), %edi # child_tid
# Copy 'fn' and 'arg' onto the child stack
movl 36(%esp), %eax # Read 'fn'.
movl %eax, -16(%ecx) # Write 'fn'.
movl 40(%esp), %eax # Read 'arg'.
movl %eax, -12(%ecx) # Write 'arg'.
subl $16, %ecx
# Make the system call.
movl $__NR_clone, %eax
int $0x80
# Check result.
testl %eax, %eax
jz .L_bc_child
jg .L_bc_parent
# An error occurred, so set errno and return -1.
negl %eax
pushl %eax
call __set_errno_internal
addl $4, %esp
jmp .L_bc_return
.L_bc_child:
# We don't want anyone to unwind past this point.
.cfi_undefined %eip
call __start_thread
hlt
.L_bc_parent:
# We're the parent; nothing to do.
.L_bc_return:
popl %edi
popl %esi
popl %ebx
ret
END(__bionic_clone)
.hidden __bionic_clone