MdeModulePkg/PiSmmCore: remove NX attr for SMM RAM

If PcdDxeNxMemoryProtectionPolicy is set to enable protection for memory
of EfiReservedMemoryType, the BIOS will hang at a page fault exception
during starting SMM driver.

The root cause is that SMM RAM is type of EfiReservedMemoryType and
marked as non-executable. The fix is simply removing NX attribute for
those memory.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>

1 files changed, 16 insertions, 2 deletions

diff --git a/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c b/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c
index a7663ca291..94d671bd74 100644
--- a/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c
+++ b/MdeModulePkg/Core/PiSmmCore/PiSmmIpl.c
@@ -1550,6 +1550,7 @@ SmmIplEntry (
   EFI_CPU_ARCH_PROTOCOL           *CpuArch;

   EFI_STATUS                      SetAttrStatus;

   EFI_SMRAM_DESCRIPTOR            *SmramRangeSmmDriver;

+  EFI_GCD_MEMORY_SPACE_DESCRIPTOR MemDesc;

 

   //

   // Fill in the image handle of the SMM IPL so the SMM Core can use this as the 

@@ -1616,7 +1617,8 @@ SmmIplEntry (
 

     GetSmramCacheRange (mCurrentSmramRange, &mSmramCacheBase, &mSmramCacheSize);

     //

-    // If CPU AP is present, attempt to set SMRAM cacheability to WB

+    // If CPU AP is present, attempt to set SMRAM cacheability to WB and clear

+    // XP if it's set.

     // Note that it is expected that cacheability of SMRAM has been set to WB if CPU AP

     // is not available here.

     //

@@ -1630,7 +1632,19 @@ SmmIplEntry (
                       );

       if (EFI_ERROR (Status)) {

         DEBUG ((DEBUG_WARN, "SMM IPL failed to set SMRAM window to EFI_MEMORY_WB\n"));

-      }  

+      }

+

+      Status = gDS->GetMemorySpaceDescriptor(

+                      mCurrentSmramRange->PhysicalStart,

+                      &MemDesc

+                      );

+      if (!EFI_ERROR (Status) && (MemDesc.Attributes & EFI_MEMORY_XP) != 0) {

+        gDS->SetMemorySpaceAttributes (

+               mCurrentSmramRange->PhysicalStart,

+               mCurrentSmramRange->PhysicalSize,

+               MemDesc.Attributes & (~EFI_MEMORY_XP)

+               );

+      }

     }

     //

     // if Loading module at Fixed Address feature is enabled, save the SMRAM base to Load