Clean up using FIQ as ctrl-c checker so you can break in from the debugger.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10390 6f19259b-4bc3-4df7-8a09-765794883524

4 files changed, 54 insertions, 25 deletions

diff --git a/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.S b/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.S
index bb4d17c5ad..c85dc0b33b 100755
--- a/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.S
+++ b/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.S
@@ -94,7 +94,7 @@ ASM_PFX(Fiq):
 ASM_PFX(UndefinedInstructionEntry):
   sub       LR, LR, #4                @ Only -2 for Thumb, adjust in CommonExceptionEntry
   srsdb     #0x13!                    @ Store return state on SVC stack
-  cps       #0x13                     @ Switch to SVC for common stack
+  cpsid     f,#0x13                   @ Switch to SVC for common stack
   stmfd     SP!,{LR}                  @ Store the link register for the current mode
   sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              @ Store the register state
@@ -106,7 +106,7 @@ ASM_PFX(UndefinedInstructionEntry):
 ASM_PFX(SoftwareInterruptEntry):
   sub       LR, LR, #4                @ Only -2 for Thumb, adjust in CommonExceptionEntry
   srsdb     #0x13!                    @ Store return state on SVC stack
-                                      @ We are already in SVC mode
+  cpsid     f                         @ We are already in SVC mode
   stmfd     SP!,{LR}                  @ Store the link register for the current mode
   sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              @ Store the register state
@@ -118,7 +118,7 @@ ASM_PFX(SoftwareInterruptEntry):
 ASM_PFX(PrefetchAbortEntry):
   sub       LR,LR,#4
   srsdb     #0x13!                    @ Store return state on SVC stack
-  cps       #0x13                     @ Switch to SVC for common stack
+  cpsid     f,#0x13                   @ Switch to SVC for common stack
   stmfd     SP!,{LR}                  @ Store the link register for the current mode
   sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              @ Store the register state
@@ -130,7 +130,7 @@ ASM_PFX(PrefetchAbortEntry):
 ASM_PFX(DataAbortEntry):
   sub       LR,LR,#8
   srsdb     #0x13!                    @ Store return state on SVC stack
-  cps       #0x13                     @ Switch to SVC for common stack
+  cpsid     f,#0x13                   @ Switch to SVC for common stack
   stmfd     SP!,{LR}                  @ Store the link register for the current mode
   sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              @ Store the register state
@@ -141,7 +141,7 @@ ASM_PFX(DataAbortEntry):
 
 ASM_PFX(ReservedExceptionEntry):
   srsdb     #0x13!                    @ Store return state on SVC stack
-  cps       #0x13                     @ Switch to SVC for common stack
+  cpsid     f,#0x13                   @ Switch to SVC for common stack
   stmfd     SP!,{LR}                  @ Store the link register for the current mode
   sub       SP,SP,#0x20               @ Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              @ Store the register state
diff --git a/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.asm b/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.asm
index 3dccf5b077..346867149a 100755
--- a/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.asm
+++ b/EmbeddedPkg/Library/GdbDebugAgent/Arm/ExceptionSupport.ARMv6.asm
@@ -95,7 +95,7 @@ Fiq
 UndefinedInstructionEntry
   sub       LR, LR, #4                ; Only -2 for Thumb, adjust in CommonExceptionEntry
   srsfd     #0x13!                    ; Store return state on SVC stack
-  cps       #0x13                     ; Switch to SVC for common stack
+  cpsid     f, #0x13                  ; Switch to SVC for common stack
   stmfd     SP!,{LR}                  ; Store the link register for the current mode
   sub       SP,SP,#0x20               ; Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              ; Store the register state
@@ -107,7 +107,7 @@ UndefinedInstructionEntry
 SoftwareInterruptEntry
   sub       LR, LR, #4                ; Only -2 for Thumb, adjust in CommonExceptionEntry
   srsfd     #0x13!                    ; Store return state on SVC stack
-                                      ; We are already in SVC mode
+  cpsid     f                         ; We are already in SVC mode
   stmfd     SP!,{LR}                  ; Store the link register for the current mode
   sub       SP,SP,#0x20               ; Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              ; Store the register state
@@ -119,7 +119,7 @@ SoftwareInterruptEntry
 PrefetchAbortEntry
   sub       LR,LR,#4
   srsfd     #0x13!                    ; Store return state on SVC stack
-  cps       #0x13                     ; Switch to SVC for common stack
+  cpsid     f, #0x13                  ; Switch to SVC for common stack
   stmfd     SP!,{LR}                  ; Store the link register for the current mode
   sub       SP,SP,#0x20               ; Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              ; Store the register state
@@ -131,7 +131,7 @@ PrefetchAbortEntry
 DataAbortEntry
   sub       LR,LR,#8
   srsfd     #0x13!                    ; Store return state on SVC stack
-  cps       #0x13                     ; Switch to SVC for common stack
+  cpsid     f, #0x13                  ; Switch to SVC for common stack
   stmfd     SP!,{LR}                  ; Store the link register for the current mode
   sub       SP,SP,#0x20               ; Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              ; Store the register state
@@ -142,7 +142,7 @@ DataAbortEntry
 
 ReservedExceptionEntry
   srsfd     #0x13!                    ; Store return state on SVC stack
-  cps       #0x13                     ; Switch to SVC for common stack
+  cpsid     f, #0x13                  ; Switch to SVC for common stack
   stmfd     SP!,{LR}                  ; Store the link register for the current mode
   sub       SP,SP,#0x20               ; Save space for SP, LR, PC, IFAR - CPSR
   stmfd     SP!,{R0-R12}              ; Store the register state
diff --git a/EmbeddedPkg/Library/GdbDebugAgent/Arm/Processor.c b/EmbeddedPkg/Library/GdbDebugAgent/Arm/Processor.c
index e09e18d6c1..21c868aeb2 100755
--- a/EmbeddedPkg/Library/GdbDebugAgent/Arm/Processor.c
+++ b/EmbeddedPkg/Library/GdbDebugAgent/Arm/Processor.c
@@ -467,6 +467,33 @@ ProcessorSendTSignal (
 }
 

 /**

+ FIQ state is only changed by FIQ exception. We don't want to take FIQ

+ ticks in the GDB stub. The stub disables FIQ on entry, but this is the 

+ third instruction that executes in the execption handler. Thus we have

+ a crack we need to test for.

+

+ @param PC     PC of execption

+

+ @return  TRUE  We are in the GDB stub exception preamble 

+ @return  FALSE We are not in GDB stub code

+ **/
+BOOLEAN
+InFiqCrack (
+  IN UINT32 PC
+  )
+{
+  UINT32 VectorBase = PcdGet32 (PcdCpuVectorBaseAddress);
+  UINT32 Length     = (UINTN)ExceptionHandlersEnd - (UINTN)ExceptionHandlersStart;
+
+  if ((PC >= VectorBase) && (PC <= (VectorBase + Length))) {
+    return TRUE;
+  }
+
+  return FALSE;
+}
+

+

+/**

  Check to see if this exception is related to ctrl-c handling.

 

  In this scheme we dedicate FIQ to the ctrl-c handler so it is 

@@ -486,6 +513,7 @@ ProcessorControlC (
   IN OUT EFI_SYSTEM_CONTEXT     SystemContext 

   )

 {

+  CHAR8     Char;

   BOOLEAN   Return = TRUE;

 

   if (ExceptionType != EXCEPT_ARM_FIQ) {

@@ -493,6 +521,12 @@ ProcessorControlC (
     return FALSE;

   }

 

+  if (InFiqCrack (SystemContext.SystemContextArm->PC)) {

+    // We are in our own interrupt preable, so skip this tick.

+    // We never want to let gdb see the debug stub running if we can help it

+    return FALSE;

+  }

+

   while (TRUE) {
     if (!GdbIsCharAvailable ()) {
       //
@@ -502,7 +536,8 @@ ProcessorControlC (
       break;
     }
     
-    if (GdbGetChar () == 0x03) {
+    Char = GdbGetChar ();
+    if (Char == 0x03) {
       //
       // We have a ctrl-c so exit and process exception for ctrl-c
       //
@@ -527,7 +562,8 @@ ProcessorControlC (
 

   @param[in] EnableStatus    Enable/Disable.

 

-  @return FALSE always.

+  @retval TRUE  Debug timer interrupt were enabled on entry to this call.

+  @retval FALSE Debug timer interrupt were disabled on entry to this call.

 

 **/

 BOOLEAN

@@ -541,7 +577,7 @@ SaveAndSetDebugTimerInterrupt (
   FiqEnabled = ArmGetFiqState ();

 

   if (EnableStatus) {

-    DebugAgentTimerSetPeriod (100);

+    DebugAgentTimerSetPeriod (PcdGet32 (PcdGdbTimerPeriodMilliseconds));

     ArmEnableFiq ();

   } else {

     DebugAgentTimerSetPeriod (0);

@@ -551,6 +587,8 @@ SaveAndSetDebugTimerInterrupt (
   return FiqEnabled;

 }

 

+

+

 VOID

 GdbFPutString (

   IN CHAR8  *String

@@ -575,21 +613,14 @@ InitializeDebugAgent (
   UINTN                Offset;

   UINTN                Length;

   BOOLEAN              IrqEnabled;

-  BOOLEAN              FiqEnabled;

   UINT32               *VectorBase;

 

-    
+
   //

   // Disable interrupts

   //

   IrqEnabled = ArmGetInterruptState ();

   ArmDisableInterrupts ();

-

-  //

-  // EFI does not use the FIQ, but a debugger might so we must disable 

-  // as we take over the exception vectors. 

-  //

-  FiqEnabled = ArmGetFiqState ();

   ArmDisableFiq ();

 

   //

@@ -615,12 +646,9 @@ InitializeDebugAgent (
   // Flush Caches since we updated executable stuff

   InvalidateInstructionCacheRange ((VOID *)PcdGet32(PcdCpuVectorBaseAddress), Length);

 

+  // setup a timer so gdb can break in via ctrl-c

   DebugAgentTimerIntialize ();

 

-  if (FiqEnabled) {

-    ArmEnableFiq ();

-  }

-

   if (IrqEnabled) {

     ArmEnableInterrupts ();

   }

diff --git a/EmbeddedPkg/Library/GdbDebugAgent/GdbDebugAgent.inf b/EmbeddedPkg/Library/GdbDebugAgent/GdbDebugAgent.inf
index 9ccb90bf4b..ed006dcabd 100755
--- a/EmbeddedPkg/Library/GdbDebugAgent/GdbDebugAgent.inf
+++ b/EmbeddedPkg/Library/GdbDebugAgent/GdbDebugAgent.inf
@@ -64,6 +64,7 @@
 

 [FixedPcd.common]

   gEmbeddedTokenSpaceGuid.PcdGdbMaxPacketRetryCount

+  gEmbeddedTokenSpaceGuid.PcdGdbTimerPeriodMilliseconds

 

 [FixedPcd.arm]

   gArmTokenSpaceGuid.PcdCpuVectorBaseAddress