From: Vivek Goyal <vgoyal@redhat.com>
Subject: [PATCH][RHEL5 BZ# 215954] x86_64: check and enable NXbit support  during resume
Date: Thu, 30 Nov 2006 17:17:55 -0500
Bugzilla: 215954
Message-Id: <456F5893.30102@redhat.com>
Changelog: x86_64: check and enable NXbit support during resume




o Relocatable patches got rid of the code which checked for NX bit support
  and enabling that bit during resume operation.

o This fails resume operations on the system which support NX bit, I think
  because it treis to load a page table which has got NX bit set as cpu
  supported NX bit.

o Restoring that piece of code back.

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
---

 arch/x86_64/kernel/acpi/wakeup.S |   17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff -puN arch/x86_64/kernel/acpi/wakeup.S~x86_64-check-and-enable-NX-bit-support-during-resume arch/x86_64/kernel/acpi/wakeup.S
--- linux-2.6.18.x86_64-2747/arch/x86_64/kernel/acpi/wakeup.S~x86_64-check-and-enable-NX-bit-support-during-resume	2006-11-20 22:42:05.000000000 -0500
+++ linux-2.6.18.x86_64-2747-root/arch/x86_64/kernel/acpi/wakeup.S	2006-11-20 22:48:16.000000000 -0500
@@ -114,9 +114,22 @@ wakeup_32:
 	leal	(wakeup_level4_pgt - wakeup_code)(%esi), %eax
 	movl	%eax, %cr3
 
+	/* Check if nx is implemented */
+	movl	$0x80000001, %eax
+	cpuid
+	movl	%edx,%edi
+
 	/* Enable Long Mode */
-	movl	$MSR_EFER, %ecx
-	movl	$(1 << _EFER_LME), %eax	# Enable Long Mode
+	xorl	%eax, %eax
+	btsl	$_EFER_LME, %eax
+
+	/* No Execute supported? */
+	btl	$20,%edi
+	jnc	1f
+	btsl	$_EFER_NX, %eax
+
+	/* Make changes effective */
+1:	movl	$MSR_EFER, %ecx
 	xorl	%edx, %edx
 	wrmsr
 
_