On Thu, 26 Feb 2015 15:37:37 -0800 Kees Cook [off-list ref] wrote:

Agh, no, please let's avoid the CONFIG addition.

That is precisely how we do this.

Hector mentioned in private mail that he was looking at an alternative
that adds exec_base to struct mm which would avoid all this insanity.

Can't we do something like:

#ifndef mmap_rnd
# define mmap_rnd 0
#endif

Sure, and sprinkle

#define mmap_rnd mmap_rnd

in five arch header files where nobody thinks to look.

For better or for worse, we are consolidating such things into arch/*/Kconfig.