x86, cpu: Call verify_cpu during 32bit CPU startup

The XD_DISABLE-clearing side-effect needs to happen for both 32bit
and 64bit, but the 32bit init routines were not calling verify_cpu()
yet. This adds that call to gain the side-effect.

The longmode/SSE tests being performed in verify_cpu() need to happen very
early for 64bit but not for 32bit. Instead of including it in two places
for 32bit, we can just include it once in arch/x86/kernel/head_32.S.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
LKML-Reference: <1289414154-7829-4-git-send-email-kees.cook@canonical.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index bcece91dd311..fdaea523ac8f 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -314,6 +314,10 @@ ENTRY(startup_32_smp)
         subl $0x80000001, %eax
         cmpl $(0x8000ffff-0x80000001), %eax
         ja 6f
+
+        /* Clear bogus XD_DISABLE bits */
+        call verify_cpu
+
         mov $0x80000001, %eax
         cpuid
         /* Execute Disable bit supported? */
@@ -609,6 +613,8 @@ ignore_int:
 #endif
         iret
 
+#include "verify_cpu.S"
+
         __REFDATA
 .align 4
 ENTRY(initial_code)