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, 3 insertions, 0 deletions

diff --git a/include/asm-powerpc/a.out.h b/include/asm-powerpc/a.out.h
index c7393a977364..5c5ea83f9349 100644
--- a/include/asm-powerpc/a.out.h
+++ b/include/asm-powerpc/a.out.h
@@ -26,9 +26,12 @@ struct exec
 #define STACK_TOP (test_thread_flag(TIF_32BIT) ? \
                    STACK_TOP_USER32 : STACK_TOP_USER64)
 
+#define STACK_TOP_MAX STACK_TOP_USER64
+
 #else /* __powerpc64__ */
 
 #define STACK_TOP TASK_SIZE
+#define STACK_TOP_MAX   STACK_TOP
 
 #endif /* __powerpc64__ */
 #endif /* __KERNEL__ */