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/* Wrapper around clone system call.
Copyright (C) 1997, 1998 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 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,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <sysdep.h>
#define _ERRNO_H 1
#include <bits/errno.h>
/* 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 clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */
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)
stmw %r29,16(%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 %r29,%r3 /* Function in r29. */
mr %r30,%r4 /* Stack pointer in r30. */
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
/* 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. */
/* On at least mklinux DR3a5, clone() doesn't actually change
the stack pointer. I'm pretty sure this is a bug, because
it adds a race condition if a signal is sent to a thread
just after it is created (in the previous three instructions). */
mr %r1,%r30
/* Call procedure. */
mtctr %r29
mr %r3,%r31
bctrl
/* Call _exit with result from procedure. */
b JUMPTARGET(_exit)
L(parent):
/* Parent. Restore registers & return. */
lmw %r29,16(%r1)
addi %r1,%r1,32
bnslr+
b JUMPTARGET(__syscall_error)
L(badargs):
li %r3,EINVAL
b JUMPTARGET(__syscall_error)
END (__clone)
weak_alias (__clone, clone)
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