IntelFsp2Pkg: FSP should not override IDT

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1265

FSP should not override IDT table when it is initialized
by boot loader. IDT should be re-initialized in FSP only
when it is invalid.
To mitigate temporary memory usage a PCD
PcdFspMaxInterruptSupported created for platform to decide
how many interrupts the FSP IDT table can support.

Test: Verified on internal platform and boots successfully.

Cc: Jiewen Yao <Jiewen.yao@intel.com>
Cc: Desimone Nathaniel L <nathaniel.l.desimone@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Chasel Chiu <chasel.chiu@intel.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>

1 files changed, 19 insertions, 5 deletions

diff --git a/IntelFsp2Pkg/FspSecCore/SecMain.c b/IntelFsp2Pkg/FspSecCore/SecMain.c
index 37fd4dfdeb..ddbfc4fcdf 100644
--- a/IntelFsp2Pkg/FspSecCore/SecMain.c
+++ b/IntelFsp2Pkg/FspSecCore/SecMain.c
@@ -70,6 +70,7 @@ SecStartup (
   UINT32                      Index;

   FSP_GLOBAL_DATA             PeiFspData;

   UINT64                      ExceptionHandler;

+  UINTN                       IdtSize;

 

   //

   // Process all libraries constructor function linked to SecCore.

@@ -98,13 +99,26 @@ SecStartup (
   // |                   |

   // |-------------------|---->  TempRamBase

   IdtTableInStack.PeiService  = NULL;

-  ExceptionHandler = FspGetExceptionHandler(mIdtEntryTemplate);

-  for (Index = 0; Index < SEC_IDT_ENTRY_COUNT; Index ++) {

-    CopyMem ((VOID*)&IdtTableInStack.IdtTable[Index], (VOID*)&ExceptionHandler, sizeof (UINT64));

+  AsmReadIdtr (&IdtDescriptor);

+  if ((IdtDescriptor.Base == 0) && (IdtDescriptor.Limit == 0xFFFF)) {

+    ExceptionHandler = FspGetExceptionHandler(mIdtEntryTemplate);

+    for (Index = 0; Index < FixedPcdGet8(PcdFspMaxInterruptSupported); Index ++) {

+      CopyMem ((VOID*)&IdtTableInStack.IdtTable[Index], (VOID*)&ExceptionHandler, sizeof (UINT64));

+    }

+    IdtSize = sizeof (IdtTableInStack.IdtTable);

+  } else {

+    if (IdtDescriptor.Limit + 1 > sizeof (IdtTableInStack.IdtTable)) {

+      //

+      // ERROR: IDT table size from boot loader is larger than FSP can support, DeadLoop here!

+      //

+      CpuDeadLoop();

+    } else {

+      IdtSize = IdtDescriptor.Limit + 1;

+    }

+    CopyMem ((VOID *) (UINTN) &IdtTableInStack.IdtTable, (VOID *) IdtDescriptor.Base, IdtSize);

   }

-

   IdtDescriptor.Base  = (UINTN) &IdtTableInStack.IdtTable;

-  IdtDescriptor.Limit = (UINT16)(sizeof (IdtTableInStack.IdtTable) - 1);

+  IdtDescriptor.Limit = (UINT16)(IdtSize - 1);

 

   AsmWriteIdtr (&IdtDescriptor);