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/* Wrapper around clone system call.
Copyright (C) 1997-2016 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/>. */
#include <sysdep.h>
#define _ERRNO_H 1
#include <bits/errno.h>
#define CLONE_VM 0x00000100
#define CLONE_THREAD 0x00010000
/* This is the only really unusual system call in PPC linux, but not
because of any weirdness in the system call itself; because of
all the freaky stuff we have to do to make the call useful. */
/* int [r3] clone(int (*fn)(void *arg) [r3], void *child_stack [r4],
int flags [r5], void *arg [r6], void *parent_tid [r7],
void *tls [r8], void *child_tid [r9]); */
ENTRY (__clone)
/* Check for child_stack == NULL || fn == NULL. */
cmpwi cr0,r4,0
cmpwi cr1,r3,0
cror cr0*4+eq,cr1*4+eq,cr0*4+eq
beq- cr0,L(badargs)
/* Set up stack frame for parent. */
stwu r1,-32(r1)
cfi_adjust_cfa_offset (32)
stmw r28,16(r1)
/* Set up stack frame for child. */
clrrwi r4,r4,4
li r0,0
stwu r0,-16(r4)
/* Save fn, args, stack across syscall. */
mr r30,r3 /* Function in r30. */
mr r28,r5
mr r31,r6 /* Argument in r31. */
/* 'flags' argument is first parameter to clone syscall. (The other
argument is the stack pointer, already in r4.) */
mr r3,r5
/* Move the parent_tid, child_tid and tls arguments. */
mr r5,r7
mr r6,r8
mr r7,r9
/* End FDE now, because in the child the unwind info will be
wrong. */
cfi_endproc
/* Do the call. */
DO_CALL(SYS_ify(clone))
/* Check for child process. */
cmpwi cr1,r3,0
crandc cr1*4+eq,cr1*4+eq,cr0*4+so
bne- cr1,L(parent) /* The '-' is to minimise the race. */
andis. r0,r28,CLONE_THREAD>>16
bne+ r0,L(oldpid)
andi. r0,r28,CLONE_VM
li r3,-1
bne- r0,L(nomoregetpid)
DO_CALL(SYS_ify(getpid))
L(nomoregetpid):
stw r3,TID(r2)
stw r3,PID(r2)
L(oldpid):
/* Call procedure. */
mtctr r30
mr r3,r31
bctrl
/* Call _exit with result from procedure. */
b HIDDEN_JUMPTARGET(_exit)
L(parent):
/* Parent. Restore registers & return. */
lmw r28,16(r1)
addi r1,r1,32
bnslr+
b __syscall_error@local
L(badargs):
li r3,EINVAL
b __syscall_error@local
cfi_startproc
END (__clone)
weak_alias (__clone, clone)
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