Replace manual casts with a direct `(__tcbhead_t __seg_gs *)0`
dereferences for `stack_guard` and `pointer_guard`. This makes
the macros more straightforward and removes the dependency on
<stdint.h>.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
The pointer guard used for pointer mangling was not initialized for
static applications resulting in the security feature being disabled.
The pointer guard is now correctly initialized to a random value for
static applications. Existing static applications need to be
recompiled to take advantage of the fix.
The test tst-ptrguard1-static and tst-ptrguard1 add regression
coverage to ensure the pointer guards are sufficiently random
and initialized to a default value.
