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/* Copyright (C) 2001, 2005 Free Software Foundation, Inc.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. 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 <features.h>
#include <sysdep.h>
#define _ERRNO_H 1
#include <bits/errno.h>
#define __ASSEMBLY__
#include <linux/sched.h>
/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
a2 a3 a4 a5
pid_t *ptid, struct user_desc *tls, pid_t *ctid)
a6 a7 16(sp)
*/
.text
ENTRY (__clone)
/* Sanity check arguments. */
beqz a2, .Leinval /* no NULL function pointers */
beqz a3, .Leinval /* no NULL stack pointers */
/* a2 and a3 are candidates for destruction by system-call return
parameters. We don't need the stack pointer after the system
call. We trust that the kernel will preserve a6, a7 and a9. */
mov a9, a5 /* save function argument */
mov a5, a7
mov a7, a2 /* save function pointer */
mov a8, a6 /* use a8 as a temp */
mov a6, a4
mov a4, a8
l32i a8, a1, FRAMESIZE /* child_tid */
movi a2, SYS_ify(clone)
/* syscall(NR_clone,clone_flags, usp, parent_tid, child_tls, child_tid)
a2 a6 a3 a4 a5 a8
*/
syscall
bltz a2, SYSCALL_ERROR_LABEL
beqz a2, .Lthread_start
/* fall through for parent */
.Lpseudo_end:
abi_ret
.Leinval:
movi a2, -EINVAL
j SYSCALL_ERROR_LABEL
.Lthread_start:
#if CLONE_THREAD != 0x00010000 || CLONE_VM != 0x00000100
# error invalid values for CLONE_THREAD or CLONE_VM
#endif
/* start child thread */
movi a0, 0 /* terminate the stack frame */
#if defined(__XTENSA_WINDOWED_ABI__)
mov a6, a9 /* load up the 'arg' parameter */
callx4 a7 /* call the user's function */
/* Call _exit. Note that any return parameter from the user's
function in a6 is seen as inputs to _exit. */
movi a2, JUMPTARGET(_exit)
callx4 a2
#elif defined(__XTENSA_CALL0_ABI__)
mov a2, a9 /* load up the 'arg' parameter */
callx0 a7 /* call the user's function */
/* Call _exit. Note that any return parameter from the user's
function in a2 is seen as inputs to _exit. */
movi a0, JUMPTARGET(_exit)
callx0 a0
#else
#error Unsupported Xtensa ABI
#endif
PSEUDO_END (__clone)
weak_alias (__clone, clone)
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