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- /* Wrapper around clone system call.
- Copyright (C) 1997, 1998, 1999, 2000 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, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
- #include "ppc_asm.h"
- #define _ERRNO_H 1
- #include <bits/errno.h>
- #include <sys/syscall.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 [r3] clone(int (*fn)(void *arg) [r3], void *child_stack [r4],
- int flags [r5], void *arg [r6]); */
- #ifdef __NR_clone
- .globl __clone
- .type __clone,@function
- .align 2
- __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,.Lbadargs
- /* 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. */
- li 0, __NR_clone
- sc
- /* Check for child process. */
- cmpwi cr1,r3,0
- crandc cr1*4+eq,cr1*4+eq,cr0*4+so
- bne- cr1,.Lparent /* 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. */
- #ifdef __PIC__
- b _exit@plt
- #else
- b _exit
- #endif
- .Lparent:
- /* Parent. Restore registers & return. */
- lmw r29,16(r1)
- addi r1,r1,32
- bnslr+
- b __syscall_error
- .Lbadargs:
- li r3,EINVAL
- b __syscall_error
- .size __clone,.-__clone
- .weak clone
- clone=__clone
- #endif
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