From: mdkinney <mdkinney@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Tue, 28 Nov 2006 02:42:44 +0000 (+0000)
Subject: Align the top of the stack correctly when the PEI Core calls SwitchStack()
X-Git-Tag: edk2-stable201903~23855
X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=commitdiff_plain;h=62332e5da35ad775d514a5ffad708d49bd1dbbae

Align the top of the stack correctly when the PEI Core calls SwitchStack()


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2022 6f19259b-4bc3-4df7-8a09-765794883524
---

diff --git a/EdkModulePkg/Core/Pei/Dispatcher/Dispatcher.c b/EdkModulePkg/Core/Pei/Dispatcher/Dispatcher.c
index b0de859073..ccd840d376 100644
--- a/EdkModulePkg/Core/Pei/Dispatcher/Dispatcher.c
+++ b/EdkModulePkg/Core/Pei/Dispatcher/Dispatcher.c
@@ -63,6 +63,7 @@ Returns:
   BOOLEAN                           NextFvFound;
   EFI_FIRMWARE_VOLUME_HEADER        *NextFvAddress;
   EFI_FIRMWARE_VOLUME_HEADER        *DefaultFvAddress;
+  VOID                              *TopOfStack;
   //
   // Debug data for uninstalled Peim list
   //
@@ -204,15 +205,16 @@ Returns:
                 PrivateDataInMem = (UINTN) TransferOldDataToNewDataRange (PrivateData);
                 ASSERT (PrivateDataInMem != 0);
                 //
-                //Subtract 0x10 from the 4th parameter indicating the new stack base,
-                //in order to provide buffer protection against possible illegal stack
-                //access that might corrupt the stack.
+                // Adjust the top of stack to be aligned at CPU_STACK_ALIGNMENT
                 //
+                TopOfStack = (VOID *)((UINTN)PrivateData->StackBase + (UINTN)PrivateData->StackSize - CPU_STACK_ALIGNMENT);
+                TopOfStack = ALIGN_POINTER (TopOfStack, CPU_STACK_ALIGNMENT);
+
                 PeiSwitchStacks (
                   (SWITCH_STACK_ENTRY_POINT)(UINTN)TempPtr.Raw,
                   PeiStartupDescriptor,
                   (VOID*)PrivateDataInMem,
-                  (VOID*)((UINTN)PrivateData->StackBase + (UINTN)PrivateData->StackSize),
+                  TopOfStack,
                   (VOID*)(UINTN)PrivateData->StackBase
                   );
               }