/* 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 <features.h> #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. */ b HIDDEN_JUMPTARGET(_exit) .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 #endif