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-rw-r--r--libc/sysdeps/linux/powerpc/clone.S98
1 files changed, 98 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/powerpc/clone.S b/libc/sysdeps/linux/powerpc/clone.S
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+++ b/libc/sysdeps/linux/powerpc/clone.S
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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. */
+ b _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
+.weak clean;
+clone=__clone
+#endif