xen: set _PAGE_NX in __supported_pte_mask before pagetable construction

Some 64-bit machines don't support the NX flag in ptes.
Check for NX before constructing the kernel pagetables.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 69de19168a7e..f7d0fd7ff8e1 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -42,6 +42,7 @@
 #include <asm/xen/hypervisor.h>
 #include <asm/fixmap.h>
 #include <asm/processor.h>
+#include <asm/proto.h>
 #include <asm/msr-index.h>
 #include <asm/setup.h>
 #include <asm/desc.h>
@@ -914,7 +915,6 @@ static const struct machine_ops __initdata xen_machine_ops = {
         .emergency_restart = xen_emergency_restart,
 };
 
-
 /* First C function to be called on Xen boot */
 asmlinkage void __init xen_start_kernel(void)
 {
@@ -982,6 +982,11 @@ asmlinkage void __init xen_start_kernel(void)
         if (!xen_initial_domain())
                 __supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
 
+#ifdef CONFIG_X86_64
+        /* Work out if we support NX */
+        check_efer();
+#endif
+
         /* Don't do the full vcpu_info placement stuff until we have a
            possible map and a non-dummy shared_info. */
         per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];