UefiCpuPkg/MpInitLib: put mReservedApLoopFunc in executable memory

if PcdDxeNxMemoryProtectionPolicy is enabled for EfiReservedMemoryType
of memory, #PF will be triggered for each APs after ExitBootServices
in SCRT test. The root cause is that AP wakeup code executed at that
time is stored in memory of type EfiReservedMemoryType (referenced by
global mReservedApLoopFunc), which is marked as non-executable.

This patch fixes this issue by setting memory of mReservedApLoopFunc to
be executable immediately after allocation.

Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
index fd2317924fd1fd998e0523edcaa14baef35ec3e7..e7ed21c6cd2d68268a6e5912724a2b3a791eaad5 100644 (file)
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
@@ -388,9 +388,9 @@ InitMpGlobalData (
   // Allocating it in advance since memory services are not available in\r
   // Exit Boot Services callback function.\r
   //\r
-  ApSafeBufferSize  = CpuMpData->AddressMap.RelocateApLoopFuncSize;\r
-  ApSafeBufferSize += CpuMpData->CpuCount * AP_SAFE_STACK_SIZE;\r
-\r
+  ApSafeBufferSize  = EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (\r
+                        CpuMpData->AddressMap.RelocateApLoopFuncSize\r
+                        ));\r
   Address = BASE_4GB - 1;\r
   Status  = gBS->AllocatePages (\r
                    AllocateMaxAddress,\r
@@ -399,9 +399,39 @@ InitMpGlobalData (
                    &Address\r
                    );\r
   ASSERT_EFI_ERROR (Status);\r
+\r
   mReservedApLoopFunc = (VOID *) (UINTN) Address;\r
   ASSERT (mReservedApLoopFunc != NULL);\r
-  mReservedTopOfApStack = (UINTN) Address + EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (ApSafeBufferSize));\r
+\r
+  //\r
+  // Make sure that the buffer memory is executable if NX protection is enabled\r
+  // for EfiReservedMemoryType.\r
+  // \r
+  // TODO: Check EFI_MEMORY_XP bit set or not once it's available in DXE GCD\r
+  //       service.\r
+  //\r
+  Status = gDS->GetMemorySpaceDescriptor (Address, &MemDesc);\r
+  if (!EFI_ERROR (Status)) {\r
+    gDS->SetMemorySpaceAttributes (\r
+           Address,\r
+           ApSafeBufferSize,\r
+           MemDesc.Attributes & (~EFI_MEMORY_XP)\r
+           );\r
+  }\r
+\r
+  ApSafeBufferSize = EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (\r
+                       CpuMpData->CpuCount * AP_SAFE_STACK_SIZE\r
+                       ));\r
+  Address = BASE_4GB - 1;\r
+  Status  = gBS->AllocatePages (\r
+                   AllocateMaxAddress,\r
+                   EfiReservedMemoryType,\r
+                   EFI_SIZE_TO_PAGES (ApSafeBufferSize),\r
+                   &Address\r
+                   );\r
+  ASSERT_EFI_ERROR (Status);\r
+\r
+  mReservedTopOfApStack = (UINTN) Address + ApSafeBufferSize;\r
   ASSERT ((mReservedTopOfApStack & (UINTN)(CPU_STACK_ALIGNMENT - 1)) == 0);\r
   CopyMem (\r
     mReservedApLoopFunc,\r