[PATCH] x86_64: check if Tom2 is enabled

[Yinghai Lu <Yinghai.Lu@Sun.COM>]

[PATCH] x86_64: check if Tom2 is enabled

need to applied after andi's amd special tom2 wb check patch

in amd_special_default_mtrr need to check if TOM2 is enabled

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 289ba1a..26eed57 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -641,6 +641,7 @@ early_param("disable_mtrr_trim", disable_mtrr_trim_setup);
  * Note this won't check if the MTRRs < 4GB where the magic bit doesn't
  * apply to are wrong, but so far we don't know of any such case in the wild.
  */
+#define Tom2Enabled (1U << 21)
 #define Tom2ForceMemTypeWB (1U << 22)
 
 static __init int amd_special_default_mtrr(void)
@@ -661,7 +662,8 @@ static __init int amd_special_default_mtrr(void)
 	 * Memory between 4GB and top of mem is forced WB by this magic bit.
 	 * Reserved before K8RevF, but should be zero there.
 	 */
-	if (l & Tom2ForceMemTypeWB)
+	if ((l & (Tom2Enabled | Tom2ForceMemTypeWB)) ==
+		 (Tom2Enabled | Tom2ForceMemTypeWB))
 		return 1;
 	return 0;
 }