We rely on objtool to verify AC=1 doesn't escape. However there is no
objtool support for x86_32, and thus we cannot guarantee the
correctness of the 32bit code.
Also; if you're running 32bit kernels on hardware with SMAP (which all
should have LM support afaik) you're doing it wrong anyway.
XXX: we could do the PUSHF/POPF thing in __switch_to_asm() on x86_32,
but why bother.
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
arch/x86/Kconfig | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1853,6 +1853,8 @@ config ARCH_RANDOM
config X86_SMAP
def_bool y
+ # Note: we rely on objtool to validate AC=1 doesn't escape
+ depends on HAVE_STACK_VALIDATION
prompt "Supervisor Mode Access Prevention" if EXPERT
---help---
Supervisor Mode Access Prevention (SMAP) is a security
