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/* Copyright (C) 2001, 2005, 2007 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 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 it's all over. */
#include "sysdep.h"
#include <sys/syscall.h>
#define _ERRNO_H 1
#include <bits/errno.h>
/* int clone (a2 = int (*fn)(void *arg),
a3 = void *child_stack,
a4 = int flags,
a5 = void *arg,
a6 = pid_t *ptid,
a7 = struct user_desc *tls,
16(sp) = pid_t *ctid) */
.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 a7, a9, and a6. */
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, 16 /* child_tid */
movi a2, SYS_ify (clone)
/* syscall (a2 = NR_clone,
a6 = clone_flags,
a3 = usp,
a4 = parent_tid,
a5 = child_tls,
a8 = child_tid) */
syscall
bltz a2, SYSCALL_ERROR_LABEL
beqz a2, .Lthread_start
/* Fall through for parent. */
.Lpseudo_end:
retw
.Leinval:
movi a2, -EINVAL
j SYSCALL_ERROR_LABEL
.Lthread_start:
/* Start child thread. */
movi a0, 0 /* terminate the stack frame */
#ifdef RESET_PID
/* Check and see if we need to reset the PID. */
bbsi.l a6, 16, 1f /* CLONE_THREAD = 0x00010000 */
movi a2, -1
bbsi.l a6, 8, 2f /* CLONE_VM = 0x00000100 */
movi a2, SYS_ify (getpid)
syscall
2: rur a3, THREADPTR
movi a4, PID_OFFSET
add a4, a4, a3
s32i a2, a4, 0
movi a4, TID_OFFSET
add a4, a4, a3
s32i a2, a3, 0
1:
#endif /* RESET_PID */
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
PSEUDO_END (__clone)
weak_alias (__clone, clone)
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