diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index a4b1d8d6b793319ea062e74a2bdcbd3b434405ab..a2123f291ab0c5c8dc13cc9364c3a12848a4bb2c 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -151,8 +151,13 @@ void release_thread(struct task_struct *);
 
 #ifdef __powerpc64__
 
+#ifdef CONFIG_PPC_BOOK3S_64
 /* Limit stack to 128TB */
 #define STACK_TOP_USER64 TASK_SIZE_128TB
+#else
+#define STACK_TOP_USER64 TASK_SIZE_USER64
+#endif
+
 #define STACK_TOP_USER32 TASK_SIZE_USER32
 
 #define STACK_TOP (is_32bit_task() ? \