[PATCH v2] IntelFrameworkModulePkg/Csm: Set CSM memory executable

[Ruiyu Ni <ruiyu.ni@intel.com>]

Commit b22a62be5cdc8fd19d87ec1ecfa5b28fb9be50ad
* IntelFrameworkModule/LegacyBios:Use reserved memory for legacy data
allocates reserved memory for holding legacy code/data.

But with PcdDxeNxMemoryProtectionPolicy set to certain value to
forbid execution when code is in certain type of memory, it's
possible that a platform forbids execution when code is in reserved
memory. The patch calls GCD service to allow such case otherwise
CPU exception may occur.

Code execution in BSCode area should be enabled by platform by
default.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
---
 .../Csm/LegacyBiosDxe/LegacyBios.c                 | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c
index 8f14687b28..f86d00b53f 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c
@@ -64,8 +64,9 @@ AllocateLegacyMemory (
   OUT EFI_PHYSICAL_ADDRESS      *Result
   )
 {
-  EFI_STATUS            Status;
-  EFI_PHYSICAL_ADDRESS  MemPage;
+  EFI_STATUS                      Status;
+  EFI_PHYSICAL_ADDRESS            MemPage;
+  EFI_GCD_MEMORY_SPACE_DESCRIPTOR MemDesc;
 
   //
   // Allocate Pages of memory less <= StartPageAddress
@@ -83,10 +84,21 @@ AllocateLegacyMemory (
   //
   if (!EFI_ERROR (Status)) {
     *Result = (EFI_PHYSICAL_ADDRESS) (UINTN) MemPage;
+    if (MemoryType != EfiBootServicesCode) {
+      //
+      // Make sure that the buffer can be used to store code.
+      //
+      Status = gDS->GetMemorySpaceDescriptor (MemPage, &MemDesc);
+      if (!EFI_ERROR (Status) && (MemDesc.Attributes & EFI_MEMORY_XP) != 0) {
+        Status = gDS->SetMemorySpaceAttributes (
+                        MemPage,
+                        EFI_PAGES_TO_SIZE (Pages),
+                        MemDesc.Attributes & (~EFI_MEMORY_XP)
+                        );
+      }
+    }
   }
-  //
-  // If reach here the status = EFI_SUCCESS
-  //
+
   return Status;
 }
 
-- 
2.16.1.windows.1