glibc/sysdeps/unix/sysv/linux/aarch64/clone.S
Marcus Shawcroft 75eff3fe90 Relocate AArch64 from ports to libc.
This patch moves the AArch64 port to the main sysdeps hierarchy.  The
move is essentially:

  git mv ports/sysdeps/aarch64 sysdeps/aarch64
  git mv ports/sysdeps/unix/sysv/linux/aarch64 sysdeps/unix/sysv/linux/aarch64

The README is updated and I've updated ChangeLog.aarch64 along the
lines of the ARM move.  The AArch64 build has been tested to confirm
that there were no changes in objdump -dr output or the shared
objects.
2014-02-11 11:36:00 +00:00

105 lines
2.7 KiB
ArmAsm

/* Copyright (C) 1996-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* clone() is even more special than fork() as it mucks with stacks
and invokes a function in the right context after its all over. */
#include <sysdep.h>
#define _ERRNO_H 1
#include <bits/errno.h>
#define CLONE_VM_BIT 8
#define CLONE_VM (1 << CLONE_VM_BIT)
#define CLONE_THREAD_BIT 16
#define CLONE_THREAD (1 << CLONE_THREAD_BIT)
/* int clone(int (*fn)(void *arg), x0
void *child_stack, x1
int flags, x2
void *arg, x3
pid_t *ptid, x4
struct user_desc *tls, x5
pid_t *ctid); x6
*/
.text
ENTRY(__clone)
/* Sanity check args. */
cbz x0, 1f
cbz x1, 1f
/* Insert the args onto the new stack. */
stp x0, x3, [x1, #-16]! /* Fn, arg. */
/* Do the system call. */
mov x0, x2 /* flags */
/* New sp is already in x1. */
mov x2, x4 /* ptid */
mov x3, x5 /* tls */
mov x4, x6 /* ctid */
#ifdef RESET_PID
/* We rely on the kernel preserving the argument regsiters across a
each system call so that we can inspect the flags against after
the clone call. */
mov x5, x0
#endif
mov x8, #SYS_ify(clone)
/* X0:flags, x1:newsp, x2:parenttidptr, x3:newtls, x4:childtid. */
svc 0x0
cfi_endproc
cmp x0, #0
beq 2f
blt 3f
RET
1: mov x0, #-EINVAL
3:
b syscall_error
2:
cfi_startproc
cfi_undefined (x30)
mov x29, 0
#ifdef RESET_PID
tbnz x5, #CLONE_THREAD_BIT, 3f
mov x0, #-1
tbnz x5, #CLONE_VM_BIT, 2f
mov x8, #SYS_ify(getpid)
svc 0x0
2:
mrs x1, tpidr_el0
sub x1, x1, #PTHREAD_SIZEOF
str w0, [x1, #PTHREAD_PID_OFFSET]
str w0, [x1, #PTHREAD_TID_OFFSET]
3:
#endif
/* Pick the function arg and call address from the stack and
execute. */
ldp x1, x0, [sp], #16
blr x1
/* We are done, pass the return value through x0. */
b HIDDEN_JUMPTARGET(_exit)
cfi_endproc
cfi_startproc
PSEUDO_END (__clone)
weak_alias (__clone, clone)