diff --git a/[refs] b/[refs]
index 1291930c4ba8..07ff2b6b3976 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2dadb987e09995b2910c419cdfe2307e66537649
+refs/heads/master: d839088caec6891a5070f0b1ce61031e458533a9
diff --git a/trunk/arch/powerpc/include/asm/system.h b/trunk/arch/powerpc/include/asm/system.h
index 2a4be19a92c4..f612798e1c93 100644
--- a/trunk/arch/powerpc/include/asm/system.h
+++ b/trunk/arch/powerpc/include/asm/system.h
@@ -531,7 +531,7 @@ __cmpxchg_local(volatile void *ptr, unsigned long old, unsigned long new,
 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 #endif
 
-#define arch_align_stack(x) (x)
+extern unsigned long arch_align_stack(unsigned long sp);
 
 /* Used in very early kernel initialization. */
 extern unsigned long reloc_offset(void);
diff --git a/trunk/arch/powerpc/kernel/process.c b/trunk/arch/powerpc/kernel/process.c
index 8ede428e76c0..69b9d2d3cb84 100644
--- a/trunk/arch/powerpc/kernel/process.c
+++ b/trunk/arch/powerpc/kernel/process.c
@@ -35,6 +35,8 @@
 #include <linux/utsname.h>
 #include <linux/ftrace.h>
 #include <linux/kernel_stat.h>
+#include <linux/personality.h>
+#include <linux/random.h>
 
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
@@ -1138,3 +1140,10 @@ void thread_info_cache_init(void)
 }
 
 #endif /* THREAD_SHIFT < PAGE_SHIFT */
+
+unsigned long arch_align_stack(unsigned long sp)
+{
+	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
+		sp -= get_random_int() & ~PAGE_MASK;
+	return sp & ~0xf;
+}