x86_64: Use __seg_fs qualifiers in {STACK, POINTER}_CHK_GUARD macros

Use the __seg_fs named address space qualifiers to cast reads of
the guard values in the TCB as %fs: prefixed addresses.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: H.J.Lu <hjl.tools@gmail.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

diff --git a/sysdeps/x86_64/stackguard-macros.h b/sysdeps/x86_64/stackguard-macros.h
index 1948800cd0086e292d57aff064a0a4da7c0c945d..1d4c620ff1b86f365e3be60619bd502dee3f95cc 100644 (file)
--- a/sysdeps/x86_64/stackguard-macros.h
+++ b/sysdeps/x86_64/stackguard-macros.h
@@ -1,11 +1,7 @@
 #include <stdint.h>
 
 #define STACK_CHK_GUARD \
-  ({ uintptr_t x;                                              \
-     asm ("mov %%fs:%c1, %0" : "=r" (x)                                \
-         : "i" (offsetof (tcbhead_t, stack_guard))); x; })
+  (*(uintptr_t __seg_fs *) offsetof (tcbhead_t, stack_guard))
 
 #define POINTER_CHK_GUARD \
-  ({ uintptr_t x;                                              \
-     asm ("mov %%fs:%c1, %0" : "=r" (x)                                \
-         : "i" (offsetof (tcbhead_t, pointer_guard))); x; })
+  (*(uintptr_t __seg_fs *) offsetof (tcbhead_t, pointer_guard))