arch: personality independent stack top

New arch macro STACK_TOP_MAX it gives the larges valid stack address for the
architecture in question.

It differs from STACK_TOP in that it will not distinguish between
personalities but will always return the largest possible address.

This is used to create the initial stack on execve, which we will move down to
the proper location once the binfmt code has figured out where that is.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ollie Wild <aaw@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/asm-x86_64/a.out.h b/include/asm-x86_64/a.out.h
index 7255cde06538..e789300e41a5 100644
--- a/include/asm-x86_64/a.out.h
+++ b/include/asm-x86_64/a.out.h
@@ -21,7 +21,8 @@ struct exec
 
 #ifdef __KERNEL__
 #include <linux/thread_info.h>
-#define STACK_TOP TASK_SIZE
+#define STACK_TOP       TASK_SIZE
+#define STACK_TOP_MAX   TASK_SIZE64
 #endif
 
 #endif /* __A_OUT_GNU_H__ */