[PATCH v3] 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>
Cc: Jian Wang <jian.j.wang@intel.com>
---
 .../Csm/LegacyBiosDxe/LegacyBios.c                 | 28 ++++++++++++++++++----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c
index 8f14687b28..80efe40489 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
@@ -81,12 +82,29 @@ AllocateLegacyMemory (
   // Do not ASSERT on Status error but let caller decide since some cases
   // memory is already taken but that is ok.
   //
+  if (!EFI_ERROR (Status)) {
+    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 (EFI_ERROR (Status)) {
+        gBS->FreePages (MemPage, Pages);
+      }
+    }
+  }
+
   if (!EFI_ERROR (Status)) {
     *Result = (EFI_PHYSICAL_ADDRESS) (UINTN) MemPage;
   }
-  //
-  // If reach here the status = EFI_SUCCESS
-  //
+
   return Status;
 }
 
-- 
2.16.1.windows.1