[PATCH] Allow architecture to overwrite stack flags

This is a bit neater.

include/linux/mm.h

@@ -111,10 +111,14 @@ struct vm_area_struct {
 #define VM_ACCOUNT	0x00100000	/* Is a VM accounted object */
 #define VM_HUGETLB	0x00400000	/* Huge TLB Page VM */
 
+#ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
+#define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
+#endif
+
 #ifdef CONFIG_STACK_GROWSUP
-#define VM_STACK_FLAGS	(VM_GROWSUP | VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT)
+#define VM_STACK_FLAGS	(VM_GROWSUP | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
 #else
-#define VM_STACK_FLAGS	(VM_GROWSDOWN | VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT)
+#define VM_STACK_FLAGS	(VM_GROWSDOWN | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
 #endif
 
 #define VM_READHINTMASK			(VM_SEQ_READ | VM_RAND_READ)