[PATCH] Powerpc: Use and override SETUP_GOT_ACCESS for ppc476

[Will Schmidt <will_schmidt at vnet dot ibm dot com>]

Hi, 
   This follows changes made in glibc (Subject "simplify code for
accessing the powerpc GOT"), which provides a simplified method
for accessing the powerpc GOT, and a way to override that access for
sub architectures.  This code provides a version of SETUP_GOT_ACCESS
that is suitable for the ppc476 architecture, and overrides the
ppc_got() function to match that instruction sequence.

2011-11-21  Will Schmidt  <will_schmidt@vnet.ibm.com>

	* sysdeps/powerpc/powerpc32/476/dl-machine.h: New file.  Add a
	ppc_got_476 function.
	* sysdeps/powerpc/powerpc32/476/sysdep.h: New file.  Define the
	SETUP_GOT_ACCESS macro for the 476 architecture.

diff --git a/sysdeps/powerpc/powerpc32/476/dl-machine.h b/sysdeps/powerpc/powerpc32/476/dl-machine.h
new file mode 100644
index 0000000..5470bae
--- /dev/null
+++ b/sysdeps/powerpc/powerpc32/476/dl-machine.h
@@ -0,0 +1,45 @@
+/* Machine-dependent ELF dynamic relocation inline functions.  PowerPC version.
+   Copyright (C) 1995-2002, 2003, 2005, 2006, 2011
+	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 <sysdeps/powerpc/powerpc32/dl-machine.h>
+
+#ifndef PPC_GOT_476_OVERRIDE
+#define PPC_GOT_476_OVERRIDE
+
+/* Return the value of the GOT pointer. */
+static inline Elf32_Addr * __attribute__ ((const))
+ppc_got_476 (void)
+{
+  Elf32_Addr *got;
+
+  asm ("	bl	$+8		\n"
+       "1:				\n"
+       "	b	$+8		\n"
+       "	blr			\n"
+       "	mflr %0			\n"
+       "	addis %0,%0,_GLOBAL_OFFSET_TABLE_-1b@ha\n"
+       "	addi %0,%0,_GLOBAL_OFFSET_TABLE_-1b@l\n"
+       : "=b" (got) : : "lr");
+
+  return got;
+}
+#define ppc_got() ppc_got_476()
+
+#endif /* PPC_GOT_476_OVERRIDE */
diff --git a/sysdeps/powerpc/powerpc32/476/sysdep.h b/sysdeps/powerpc/powerpc32/476/sysdep.h
new file mode 100644
index 0000000..2240207
--- /dev/null
+++ b/sysdeps/powerpc/powerpc32/476/sysdep.h
@@ -0,0 +1,45 @@
+/* Assembly macros for 32-bit PowerPC.
+   Copyright (C) 1999, 2001, 2002, 2003, 2006, 2011
+	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., 51 Franklin Street, Fifth Floor, Boston MA
+   02110-1301 USA.  */
+
+#include <sysdeps/powerpc/powerpc32/sysdep.h>
+#include <sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h>
+
+#ifdef __ASSEMBLER__
+
+#ifdef __ELF__
+
+/* helper macro for accessing the 32-bit powerpc GOT.  */
+#ifndef ACCESS_GOT_476
+#define ACCESS_GOT_476
+
+#undef SETUP_GOT_ACCESS
+
+#define	SETUP_GOT_ACCESS(regname)				\
+	bl	$+8		;				\
+1:				;				\
+	b	$+8		;				\
+	blr			;				\
+	mflr	(regname)
+
+#endif /* ACCESS_GOT_476 */
+
+#endif /* __ELF__ */
+
+#endif	/* __ASSEMBLER__ */