From 330eb7bad0aeb0f95a12eb77791bdb4b828249d4 Mon Sep 17 00:00:00 2001
From: Eric Andersen <andersen@codepoet.org>
Date: Mon, 4 Feb 2002 12:34:00 +0000
Subject: Rework powerpc to be consistant with the other arches.  -Erik

---
 libc/sysdeps/linux/powerpc/clone.S | 98 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 libc/sysdeps/linux/powerpc/clone.S

(limited to 'libc/sysdeps/linux/powerpc/clone.S')

diff --git a/libc/sysdeps/linux/powerpc/clone.S b/libc/sysdeps/linux/powerpc/clone.S
new file mode 100644
index 000000000..8aeb48262
--- /dev/null
+++ b/libc/sysdeps/linux/powerpc/clone.S
@@ -0,0 +1,98 @@
+/* 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
-- 
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