Revision: 18905
http://sourceforge.net/p/edk2/code/18905
Author: vanjeff
Date: 2015-11-20 01:22:00 +0000 (Fri, 20 Nov 2015)
Log Message:
-----------
UefiCpuPkg: Not touch SmmFeatureControl if Code_Access_Chk not Set
Bit SMM_Code_Access_Chk (SMM-RO) in MSR_SMM_MCA_CAP is defined in SDM.
If set to 1 indicates that the SMM code access restriction is supported and the
MSR_SMM_FEATURE_CONTROL is supported.
If this bit is not set, we needn't to access register SmmFetureControl.
Otherwise, #GP exception may happen.
Cc: Michael Kinney <[email protected]>
Cc: Jiewen Yao <[email protected]>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <[email protected]>
Reviewed-by: Michael Kinney <[email protected]>
Reviewed-by: Jiewen Yao <[email protected]>
Modified Paths:
--------------
trunk/edk2/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
Modified: trunk/edk2/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
===================================================================
--- trunk/edk2/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c 2015-11-19
14:39:48 UTC (rev 18904)
+++ trunk/edk2/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c 2015-11-20
01:22:00 UTC (rev 18905)
@@ -1309,10 +1309,10 @@
NewSmmFeatureControlMsr = SmmFeatureControlMsr;
if (mSmmCodeAccessCheckEnable) {
NewSmmFeatureControlMsr |= SMM_CODE_CHK_EN_BIT;
+ if (FeaturePcdGet (PcdCpuSmmFeatureControlMsrLock)) {
+ NewSmmFeatureControlMsr |= SMM_FEATURE_CONTROL_LOCK_BIT;
+ }
}
- if (FeaturePcdGet (PcdCpuSmmFeatureControlMsrLock)) {
- NewSmmFeatureControlMsr |= SMM_FEATURE_CONTROL_LOCK_BIT;
- }
//
// Only set the SMM Feature Control MSR value if the new value is different
than the current value
@@ -1354,13 +1354,6 @@
//
if ((AsmReadMsr64 (EFI_MSR_SMM_MCA_CAP) & SMM_CODE_ACCESS_CHK_BIT) == 0) {
mSmmCodeAccessCheckEnable = FALSE;
- }
-
- //
- // If the SMM Code Access Check feature is disabled and the Feature Control
MSR
- // is not being locked, then no additional work is required
- //
- if (!mSmmCodeAccessCheckEnable && !FeaturePcdGet
(PcdCpuSmmFeatureControlMsrLock)) {
return;
}
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