[PATCH v2 4/8] MdeModulePkg/DxeIpl: Enable paging for Stack Guard

[Jian J Wang <jian.j.wang@intel.com>]

Stack guard feature makes use of paging mechanism to monitor if there's a
stack overflow occurred during boot.

This patch will check setting of PCD PcdCpuStackGuard. If it's TRUE, DxeIpl
will setup page table and set the page at which the stack base locates to be
NOT PRESENT. If stack is used up and memory access cross into the last page
of it, #PF exception will be triggered.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
---
 MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf          |  5 ++-
 MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c  |  4 ++
 MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c   |  1 +
 MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 51 ++++++++++++++++++------
 4 files changed, 46 insertions(+), 15 deletions(-)

diff --git a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
index a1b8748432..ba1d9c6b05 100644
--- a/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
+++ b/MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf
@@ -49,7 +49,7 @@
 [Sources.X64]
   X64/VirtualMemory.h
   X64/VirtualMemory.c
-  X64/DxeLoadFunc.c    
+  X64/DxeLoadFunc.c
 
 [Sources.IPF]
   Ipf/DxeLoadFunc.c
@@ -117,6 +117,7 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask    ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdNullPointerDetectionPropertyMask    ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPropertyMask               ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard                       ## CONSUMES
 
 [Pcd.IA32,Pcd.X64,Pcd.ARM,Pcd.AARCH64]
   gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack               ## SOMETIMES_CONSUMES
@@ -132,7 +133,7 @@
 #
 # [Hob]
 # MEMORY_ALLOCATION                 ## SOMETIMES_PRODUCES # MEMORY_ALLOCATION_MODULE for DxeCore
-# MEMORY_ALLOCATION                 ## SOMETIMES_PRODUCES # New Stack HoB   
+# MEMORY_ALLOCATION                 ## SOMETIMES_PRODUCES # New Stack HoB
 # MEMORY_ALLOCATION                 ## SOMETIMES_PRODUCES # Old Stack HOB
 #
 # [Hob.IPF]
diff --git a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
index 5649265367..441096ad0f 100644
--- a/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
+++ b/MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
@@ -235,6 +235,10 @@ ToBuildPageTable (
     return TRUE;
   }
 
+  if (PcdGetBool (PcdCpuStackGuard)) {
+    return TRUE;
+  }
+
   if (PcdGetBool (PcdSetNxForStack) && IsExecuteDisableBitAvailable ()) {
     return TRUE;
   }
diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c b/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c
index f613221b81..b75a4489bf 100644
--- a/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c
+++ b/MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c
@@ -95,6 +95,7 @@ HandOffToDxeCore (
     // for the DxeIpl and the DxeCore are both X64.
     //
     ASSERT (PcdGetBool (PcdSetNxForStack) == FALSE);
+    ASSERT (PcdGetBool (PcdCpuStackGuard) == FALSE);
   }
   
   //
diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
index 29b6205e88..a2466b7766 100644
--- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
+++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
@@ -117,6 +117,39 @@ EnableExecuteDisableBit (
   AsmWriteMsr64 (0xC0000080, MsrRegisters);
 }
 
+/**
+  The function will check if page table entry should be splitted to smaller
+  granularity.
+
+  @retval TRUE      Page table should be created.
+  @retval FALSE     Page table should not be created.
+**/
+BOOLEAN
+ToSplitPageTable (
+  IN EFI_PHYSICAL_ADDRESS               Address,
+  IN UINTN                              Size,
+  IN EFI_PHYSICAL_ADDRESS               StackBase,
+  IN UINTN                              StackSize
+  )
+{
+  if (IsNullDetectionEnabled () && Address == 0) {
+    return TRUE;
+  }
+
+  if (PcdGetBool (PcdCpuStackGuard)) {
+    if (StackBase >= Address && StackBase < (Address + Size)) {
+      return TRUE;
+    }
+  }
+
+  if (PcdGetBool (PcdSetNxForStack)) {
+    if ((Address < StackBase + StackSize) && ((Address + Size) > StackBase)) {
+      return TRUE;
+    }
+  }
+
+  return FALSE;
+}
 /**
   Split 2M page to 4K.
 
@@ -160,7 +193,8 @@ Split2MPageTo4K (
     PageTableEntry->Uint64 = (UINT64) PhysicalAddress4K | AddressEncMask;
     PageTableEntry->Bits.ReadWrite = 1;
 
-    if (IsNullDetectionEnabled () && PhysicalAddress4K == 0) {
+    if ((IsNullDetectionEnabled () && PhysicalAddress4K == 0) ||
+        (PcdGetBool (PcdCpuStackGuard) && PhysicalAddress4K == StackBase)) {
       PageTableEntry->Bits.Present = 0;
     } else {
       PageTableEntry->Bits.Present = 1;
@@ -214,10 +248,7 @@ Split1GPageTo2M (
 
   PhysicalAddress2M = PhysicalAddress;
   for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PhysicalAddress2M += SIZE_2MB) {
-    if ((IsNullDetectionEnabled () && PhysicalAddress2M == 0)
-        || (PcdGetBool (PcdSetNxForStack)
-            && (PhysicalAddress2M < StackBase + StackSize)
-            && ((PhysicalAddress2M + SIZE_2MB) > StackBase))) {
+    if (ToSplitPageTable (PhysicalAddress2M, SIZE_2MB, StackBase, StackSize)) {
       //
       // Need to split this 2M page that covers NULL or stack range.
       //
@@ -359,10 +390,7 @@ CreateIdentityMappingPageTables (
       PageDirectory1GEntry = (VOID *) PageDirectoryPointerEntry;
     
       for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectory1GEntry++, PageAddress += SIZE_1GB) {
-        if ((IsNullDetectionEnabled () && PageAddress == 0)
-            || (PcdGetBool (PcdSetNxForStack)
-                && (PageAddress < StackBase + StackSize)
-                && ((PageAddress + SIZE_1GB) > StackBase))) {
+        if (ToSplitPageTable (PageAddress, SIZE_1GB, StackBase, StackSize)) {
           Split1GPageTo2M (PageAddress, (UINT64 *) PageDirectory1GEntry, StackBase, StackSize);
         } else {
           //
@@ -391,10 +419,7 @@ CreateIdentityMappingPageTables (
         PageDirectoryPointerEntry->Bits.Present = 1;
 
         for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PageAddress += SIZE_2MB) {
-          if ((IsNullDetectionEnabled () && PageAddress == 0)
-              || (PcdGetBool (PcdSetNxForStack)
-                  && (PageAddress < StackBase + StackSize)
-                  && ((PageAddress + SIZE_2MB) > StackBase))) {
+          if (ToSplitPageTable (PageAddress, SIZE_2MB, StackBase, StackSize)) {
             //
             // Need to split this 2M page that covers NULL or stack range.
             //
-- 
2.14.1.windows.1