[PATCH edk2-platforms v3 14/17] ARM/VExpressPkg: Set EFI_MEMORY_XP flag on GOP framebuffer

[Girish Pathak <girish.pathak@arm.com>]

The framebuffer memory is set with flag
EFI_MEMORY_WC (uncached, unbuffered) which causes framebuffer memory
with eXecute bit set. Framebuffer memory having executable bit
set is a security hazard. This fix adds EFI_MEMORY_XP flag to avoid this.
Unfortunately function gDS->SetMemorySpaceAttributes() causes assertion due
to unsupported EFI_MEMORY_XP type. Therefore this fix replaces
gDS->SetMemorySpaceAttributes() with Cpu->SetMemoryAttributes().

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Girish Pathak <girish.pathak@arm.com>
Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>
---
 Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c            | 24 ++++++++++++++------
 Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpressLib.inf       |  1 -
 Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c      | 24 ++++++++++++++------
 Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpressLib.inf |  1 -
 4 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c b/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c
index c0a25a18d3fcfe91a76ee985ee58145b97900fa0..4c114de4062ece7cee1221148afb42e66d04f07e 100644
--- a/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c
+++ b/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpress.c
@@ -17,11 +17,11 @@
 #include <Library/ArmPlatformSysConfigLib.h>
 #include <Library/PcdLib.h>
 #include <Library/DebugLib.h>
-#include <Library/DxeServicesTableLib.h>
 #include <Library/LcdPlatformLib.h>
 #include <Library/MemoryAllocationLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 
+#include <Protocol/Cpu.h>
 #include <Protocol/EdidDiscovered.h>
 #include <Protocol/EdidActive.h>
 
@@ -159,6 +159,7 @@ LcdPlatformGetVram (
 {
   EFI_STATUS              Status;
   EFI_ALLOCATE_TYPE       AllocationType;
+  EFI_CPU_ARCH_PROTOCOL   *Cpu;
 
   ASSERT (VramBaseAddress != NULL);
   ASSERT (VramSize != NULL);
@@ -185,13 +186,22 @@ LcdPlatformGetVram (
     return Status;
   }
 
-  // Mark the VRAM as write-combining.
-  // The VRAM is inside the DRAM, which is cacheable.
-  Status = gDS->SetMemorySpaceAttributes (
-                  *VramBaseAddress,
-                  *VramSize,
-                  EFI_MEMORY_WC
+  // Ensure the Cpu architectural protocol is already installed
+  Status = gBS->LocateProtocol (
+                  &gEfiCpuArchProtocolGuid,
+                  NULL,
+                  (VOID **)&Cpu
                   );
+  if (!EFI_ERROR (Status)) {
+    // The VRAM is inside the DRAM, which is cacheable.
+    // Mark the VRAM as write-combining (uncached) and non-executable.
+    Status = Cpu->SetMemoryAttributes (
+                    Cpu,
+                    *VramBaseAddress,
+                    *VramSize,
+                    EFI_MEMORY_WC | EFI_MEMORY_XP
+                    );
+  }
   if (EFI_ERROR (Status)) {
     ASSERT_EFI_ERROR (Status);
     gBS->FreePages (*VramBaseAddress, EFI_SIZE_TO_PAGES (*VramSize));
diff --git a/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpressLib.inf b/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpressLib.inf
index 9b0d358846bf367d7f9ff6f5d3fdffc204864528..c7b1b7fae77cbbf82b3a0768e7654a96719f5e7a 100644
--- a/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpressLib.inf
+++ b/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExpressLib.inf
@@ -33,7 +33,6 @@ [Packages]
 [LibraryClasses]
   ArmPlatformSysConfigLib
   BaseLib
-  DxeServicesTableLib
 
 [Protocols]
   gEfiEdidDiscoveredProtocolGuid                # Produced
diff --git a/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c b/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c
index 61ddf77e903e6c33a26b2aa8b76121e807195a9a..cae5f3a658efa4cc2be135259b63c860c26c6874 100644
--- a/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c
+++ b/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpress.c
@@ -17,10 +17,10 @@
 #include <Library/IoLib.h>
 #include <Library/PcdLib.h>
 #include <Library/DebugLib.h>
-#include <Library/DxeServicesTableLib.h>
 #include <Library/LcdPlatformLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 
+#include <Protocol/Cpu.h>
 #include <Protocol/EdidDiscovered.h>
 #include <Protocol/EdidActive.h>
 
@@ -212,6 +212,7 @@ LcdPlatformGetVram (
   )
 {
   EFI_STATUS              Status;
+  EFI_CPU_ARCH_PROTOCOL   *Cpu;
 
   ASSERT (VramBaseAddress != NULL);
   ASSERT (VramSize != NULL);
@@ -241,13 +242,22 @@ LcdPlatformGetVram (
       return Status;
     }
 
-    // Mark the VRAM as write-combining.
-    // The VRAM is inside the DRAM, which is cacheable.
-    Status = gDS->SetMemorySpaceAttributes (
-                    *VramBaseAddress,
-                    *VramSize,
-                    EFI_MEMORY_WC
+    // Ensure the Cpu architectural protocol is already installed
+    Status = gBS->LocateProtocol (
+                    &gEfiCpuArchProtocolGuid,
+                    NULL,
+                    (VOID **)&Cpu
                     );
+    if (!EFI_ERROR (Status)) {
+      // The VRAM is inside the DRAM, which is cacheable.
+      // Mark the VRAM as write-combining (uncached) and non-executable.
+      Status = Cpu->SetMemoryAttributes (
+                      Cpu,
+                      *VramBaseAddress,
+                      *VramSize,
+                      EFI_MEMORY_WC | EFI_MEMORY_XP
+                      );
+    }
     if (EFI_ERROR (Status)) {
       ASSERT_EFI_ERROR (Status);
       gBS->FreePages (*VramBaseAddress, EFI_SIZE_TO_PAGES (*VramSize));
diff --git a/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpressLib.inf b/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpressLib.inf
index 2bf14f999e633a55abd572daaac1e80ae2e648eb..b1fa100def0dd774fec50cb04a638a89b95de575 100644
--- a/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpressLib.inf
+++ b/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdArmVExpressLib.inf
@@ -33,7 +33,6 @@ [Packages]
 [LibraryClasses]
   ArmPlatformSysConfigLib
   BaseLib
-  DxeServicesTableLib
 
 [Protocols]
   gEfiEdidDiscoveredProtocolGuid                # Produced
-- 
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'