[CVE-2009-0029] powerpc: Enable syscall wrappers for 64-bit

This enables the use of syscall wrappers to do proper sign extension
for 64-bit programs.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

arch/powerpc/Kconfig

@@ -123,6 +123,7 @@ config PPC
 	select HAVE_DMA_ATTRS if PPC64
 	select USE_GENERIC_SMP_HELPERS if SMP
 	select HAVE_OPROFILE
+	select HAVE_SYSCALL_WRAPPERS if PPC64
 
 config EARLY_PRINTK
 	bool

include/linux/syscalls.h

@@ -103,8 +103,14 @@ struct old_linux_dirent;
 #define SYSCALL_DEFINE5(...)    SYSCALL_DEFINEx(5, __VA_ARGS__)
 #define SYSCALL_DEFINE6(...)    SYSCALL_DEFINEx(6, __VA_ARGS__)
 
+#ifdef CONFIG_PPC64
+#define SYSCALL_ALIAS(alias, name)					\
+	asm ("\t.globl " #alias "\n\t.set " #alias ", " #name "\n"	\
+	     "\t.globl ." #alias "\n\t.set ." #alias ", ." #name)
+#else
 #define SYSCALL_ALIAS(alias, name)					\
 	asm ("\t.globl " #alias "\n\t.set " #alias ", " #name)
+#endif
 
 #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS