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/* 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)
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