From d213712d4f858efd5cb43faa39c6d940829c9363 Mon Sep 17 00:00:00 2001
From: AJFISH <AJFISH@6f19259b-4bc3-4df7-8a09-765794883524>
Date: Fri, 8 Jan 2010 23:07:33 +0000
Subject: Fixed a bug in the HardwareInterrupt handler that would blow the
 stack if you reenable interrupts in the TimerHandler. It should be noted this
 happens as the TimerHandler raises and restores TPL for the timer tick used
 by the DXE Core. There was some work around code in the CPU driver to prevent
 interrupts from being enabled while handling exceptions. This has been
 removed.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9701 6f19259b-4bc3-4df7-8a09-765794883524
---
 ArmPkg/Drivers/CpuDxe/CpuDxe.c                  | 9 ++-------
 ArmPkg/Drivers/CpuDxe/Exception.c               | 7 +------
 BeagleBoardPkg/InterruptDxe/HardwareInterrupt.c | 4 ++++
 3 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/ArmPkg/Drivers/CpuDxe/CpuDxe.c b/ArmPkg/Drivers/CpuDxe/CpuDxe.c
index 2b43d2a..d3f0ff5 100644
--- a/ArmPkg/Drivers/CpuDxe/CpuDxe.c
+++ b/ArmPkg/Drivers/CpuDxe/CpuDxe.c
@@ -14,7 +14,6 @@
 
 #include "CpuDxe.h"
 
-BOOLEAN gExceptionContext = FALSE;
 BOOLEAN mInterruptState   = FALSE;
 
 EFI_STATUS
@@ -49,9 +48,7 @@ CpuEnableInterrupt (
   IN EFI_CPU_ARCH_PROTOCOL          *This
   )
 {
-  if (!gExceptionContext) {
-    ArmEnableInterrupts ();
-  }
+  ArmEnableInterrupts ();
 
   mInterruptState  = TRUE;
   return EFI_SUCCESS;
@@ -64,9 +61,7 @@ CpuDisableInterrupt (
   IN EFI_CPU_ARCH_PROTOCOL          *This
   )
 {
-  if (!gExceptionContext) {
-    ArmDisableInterrupts ();
-  }
+  ArmDisableInterrupts ();
 
   mInterruptState = FALSE;
   return EFI_SUCCESS;
diff --git a/ArmPkg/Drivers/CpuDxe/Exception.c b/ArmPkg/Drivers/CpuDxe/Exception.c
index 8859ca8..9910bd2 100644
--- a/ArmPkg/Drivers/CpuDxe/Exception.c
+++ b/ArmPkg/Drivers/CpuDxe/Exception.c
@@ -15,8 +15,6 @@
 #include "CpuDxe.h" 
 #include <Library/CacheMaintenanceLib.h>
 
-extern BOOLEAN gExceptionContext;
-
 VOID
 ExceptionHandlersStart (
   VOID
@@ -142,8 +140,7 @@ CommonCExceptionHandler (
 {
   BOOLEAN Dispatched = FALSE;
  
-  gExceptionContext = TRUE; 
-  
+ 
   if (ExceptionType <= MAX_ARM_EXCEPTION) {
     if (gDebuggerExceptionHandlers[ExceptionType]) {
       //
@@ -162,8 +159,6 @@ CommonCExceptionHandler (
     ASSERT (FALSE);
   }
 
-  gExceptionContext = FALSE; 
-
   if (Dispatched) {
     //
     // We did work so this was an expected ExceptionType
diff --git a/BeagleBoardPkg/InterruptDxe/HardwareInterrupt.c b/BeagleBoardPkg/InterruptDxe/HardwareInterrupt.c
index 3e69515..c87d564 100644
--- a/BeagleBoardPkg/InterruptDxe/HardwareInterrupt.c
+++ b/BeagleBoardPkg/InterruptDxe/HardwareInterrupt.c
@@ -234,12 +234,16 @@ IrqInterruptHandler (
   
   Vector = MmioRead32(INTCPS_SIR_IRQ) & INTCPS_SIR_IRQ_MASK;
 
+  // Needed to prevent infinite nesting if Time Driver lowers TPL
+  MmioWrite32(INTCPS_CONTROL, INTCPS_CONTROL_NEWIRQAGR);
+
   InterruptHandler = gRegisteredInterruptHandlers[Vector];
   if (InterruptHandler != NULL) {
     // Call the registered interrupt handler.
     InterruptHandler(Vector, SystemContext);
   }
   
+  // Needed to clear after running the handler
   MmioWrite32(INTCPS_CONTROL, INTCPS_CONTROL_NEWIRQAGR);
 }
 
-- 
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