uml: stop specially protecting kernel stacks

Map all of physical memory as executable to avoid having to change stack
protections during fork and exit.

unprotect_stack is now called only from MODE_TT code, so it is marked as such.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/kernel/init_task.c b/arch/um/kernel/init_task.c
index cba516e..fa90db9 100644
--- a/arch/um/kernel/init_task.c
+++ b/arch/um/kernel/init_task.c
@@ -47,7 +47,9 @@
 	__attribute__((__section__(".data.init_irqstack"))) =
 		{ INIT_THREAD_INFO(init_task) };
 
+#ifdef CONFIG_MODE_TT
 void unprotect_stack(unsigned long stack)
 {
 	os_protect_memory((void *) stack, THREAD_SIZE, 1, 1, 0);
 }
+#endif