Use symbolic constants rather than hard-coded values when setting
EFER.NX in head_32.S, and do a more rigorous test for the validity of
the response when probing for the extended CPUID range.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <
1258154897-6770-2-git-send-email-hpa@zytor.com>
Acked-by: Kees Cook <kees.cook@canonical.com>
#include <asm/asm-offsets.h>
#include <asm/setup.h>
#include <asm/processor-flags.h>
#include <asm/asm-offsets.h>
#include <asm/setup.h>
#include <asm/processor-flags.h>
+#include <asm/msr-index.h>
+#include <asm/cpufeature.h>
#include <asm/percpu.h>
/* Physical address */
#include <asm/percpu.h>
/* Physical address */
orl %edx,%eax
movl %eax,%cr4
orl %edx,%eax
movl %eax,%cr4
- btl $5, %eax # check if PAE is enabled
- jnc 6f
+ testb $X86_CR4_PAE, %al # check if PAE is enabled
+ jz 6f
/* Check if extended functions are implemented */
movl $0x80000000, %eax
cpuid
/* Check if extended functions are implemented */
movl $0x80000000, %eax
cpuid
- cmpl $0x80000000, %eax
- jbe 6f
+ /* Value must be in the range 0x80000001 to 0x8000ffff */
+ subl $0x80000001, %eax
+ cmpl $(0x8000ffff-0x80000001), %eax
+ ja 6f
mov $0x80000001, %eax
cpuid
/* Execute Disable bit supported? */
mov $0x80000001, %eax
cpuid
/* Execute Disable bit supported? */
+ btl $(X86_FEATURE_NX & 31), %edx
jnc 6f
/* Setup EFER (Extended Feature Enable Register) */
jnc 6f
/* Setup EFER (Extended Feature Enable Register) */
/* Make changes effective */
wrmsr
/* Make changes effective */
wrmsr