ArmPkg: Introduce the PCD PcdDebuggerExceptionSupport

[mirror_edk2.git] / ArmPkg / Drivers / CpuDxe / Exception.c

/** @file\r
\r
  Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>\r
  \r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "CpuDxe.h" \r
\r
//FIXME: Will not compile on non-ARMv7 builds\r
#include <Chipset/ArmV7.h>\r
\r
VOID\r
ExceptionHandlersStart (\r
  VOID\r
  );\r
\r
VOID\r
ExceptionHandlersEnd (\r
  VOID\r
  );\r
\r
VOID\r
CommonExceptionEntry (\r
  VOID\r
  );\r
\r
VOID\r
AsmCommonExceptionEntry (\r
  VOID\r
  );\r
\r
\r
EFI_EXCEPTION_CALLBACK  gExceptionHandlers[MAX_ARM_EXCEPTION + 1];\r
EFI_EXCEPTION_CALLBACK  gDebuggerExceptionHandlers[MAX_ARM_EXCEPTION + 1];\r
\r
\r
\r
/**\r
  This function registers and enables the handler specified by InterruptHandler for a processor \r
  interrupt or exception type specified by InterruptType. If InterruptHandler is NULL, then the \r
  handler for the processor interrupt or exception type specified by InterruptType is uninstalled. \r
  The installed handler is called once for each processor interrupt or exception.\r
\r
  @param  InterruptType    A pointer to the processor's current interrupt state. Set to TRUE if interrupts\r
                           are enabled and FALSE if interrupts are disabled.\r
  @param  InterruptHandler A pointer to a function of type EFI_CPU_INTERRUPT_HANDLER that is called\r
                           when a processor interrupt occurs. If this parameter is NULL, then the handler\r
                           will be uninstalled.\r
\r
  @retval EFI_SUCCESS           The handler for the processor interrupt was successfully installed or uninstalled.\r
  @retval EFI_ALREADY_STARTED   InterruptHandler is not NULL, and a handler for InterruptType was\r
                                previously installed.\r
  @retval EFI_INVALID_PARAMETER InterruptHandler is NULL, and a handler for InterruptType was not\r
                                previously installed.\r
  @retval EFI_UNSUPPORTED       The interrupt specified by InterruptType is not supported.\r
\r
**/\r
EFI_STATUS\r
RegisterInterruptHandler (\r
  IN EFI_EXCEPTION_TYPE             InterruptType,\r
  IN EFI_CPU_INTERRUPT_HANDLER      InterruptHandler\r
  )\r
{\r
  if (InterruptType > MAX_ARM_EXCEPTION) {\r
    return EFI_UNSUPPORTED;\r
  }\r
\r
  if ((InterruptHandler != NULL) && (gExceptionHandlers[InterruptType] != NULL)) {\r
    return EFI_ALREADY_STARTED;\r
  }\r
\r
  gExceptionHandlers[InterruptType] = InterruptHandler;\r
\r
  return EFI_SUCCESS;\r
}\r
\r
\r
\r
\r
VOID\r
EFIAPI\r
CommonCExceptionHandler (\r
  IN     EFI_EXCEPTION_TYPE           ExceptionType,\r
  IN OUT EFI_SYSTEM_CONTEXT           SystemContext\r
  )\r
{\r
\r
  if (ExceptionType <= MAX_ARM_EXCEPTION) {\r
    if (gExceptionHandlers[ExceptionType]) {\r
      gExceptionHandlers[ExceptionType] (ExceptionType, SystemContext);\r
      return;\r
    }\r
  } else {\r
    DEBUG ((EFI_D_ERROR, "Unknown exception type %d from %08x\n", ExceptionType, SystemContext.SystemContextArm->PC));\r
    ASSERT (FALSE);\r
  }\r
  \r
  if (ExceptionType == EXCEPT_ARM_SOFTWARE_INTERRUPT) {\r
    //\r
    // ARM JTAG debuggers some times use this vector, so it is not an error to get one\r
    //\r
    return;\r
  }\r
\r
  DefaultExceptionHandler (ExceptionType, SystemContext);\r
}\r
\r
\r
\r
EFI_STATUS\r
InitializeExceptions (\r
  IN EFI_CPU_ARCH_PROTOCOL    *Cpu\r
  )\r
{\r
  EFI_STATUS           Status;\r
  UINTN                Offset;\r
  UINTN                Length;\r
  UINTN                Index;\r
  BOOLEAN              IrqEnabled;\r
  BOOLEAN              FiqEnabled;\r
  EFI_PHYSICAL_ADDRESS Base;\r
  UINT32               *VectorBase;\r
\r
  Status = EFI_SUCCESS;\r
  //\r
  // Disable interrupts\r
  //\r
  Cpu->GetInterruptState (Cpu, &IrqEnabled);\r
  Cpu->DisableInterrupt (Cpu);\r
\r
  //\r
  // EFI does not use the FIQ, but a debugger might so we must disable \r
  // as we take over the exception vectors. \r
  //\r
  FiqEnabled = ArmGetFiqState ();\r
  ArmDisableFiq ();\r
\r
  if (FeaturePcdGet(PcdRelocateVectorTable) == TRUE) {\r
      //\r
      // Copy an implementation of the ARM exception vectors to PcdCpuVectorBaseAddress.\r
      //\r
      Length = (UINTN)ExceptionHandlersEnd - (UINTN)ExceptionHandlersStart;\r
    \r
      //\r
      // Reserve space for the exception handlers\r
      //\r
      Base = (EFI_PHYSICAL_ADDRESS)PcdGet32 (PcdCpuVectorBaseAddress);\r
      VectorBase = (UINT32 *)(UINTN)Base;\r
      Status = gBS->AllocatePages (AllocateAddress, EfiBootServicesCode, EFI_SIZE_TO_PAGES (Length), &Base);\r
      // If the request was for memory that's not in the memory map (which is often the case for 0x00000000\r
      // on embedded systems, for example, we don't want to hang up.  So we'll check here for a status of \r
      // EFI_NOT_FOUND, and continue in that case.\r
      if (EFI_ERROR(Status) && (Status != EFI_NOT_FOUND)) {\r
        ASSERT_EFI_ERROR (Status);\r
      }\r
    \r
    if (FeaturePcdGet(PcdDebuggerExceptionSupport) == TRUE) {\r
      // Save existing vector table, in case debugger is already hooked in\r
      CopyMem ((VOID *)gDebuggerExceptionHandlers, (VOID *)VectorBase, sizeof (gDebuggerExceptionHandlers));\r
    }\r
    \r
      // Copy our assembly code into the page that contains the exception vectors. \r
      CopyMem ((VOID *)VectorBase, (VOID *)ExceptionHandlersStart, Length);\r
    \r
      //\r
      // Patch in the common Assembly exception handler\r
      //\r
      Offset = (UINTN)CommonExceptionEntry - (UINTN)ExceptionHandlersStart;\r
      *(UINTN *) ((UINT8 *)(UINTN)PcdGet32 (PcdCpuVectorBaseAddress) + Offset) = (UINTN)AsmCommonExceptionEntry;\r
    \r
      //\r
      // Initialize the C entry points for interrupts\r
      //\r
      for (Index = 0; Index <= MAX_ARM_EXCEPTION; Index++) {\r
      if (!FeaturePcdGet(PcdDebuggerExceptionSupport) ||\r
          (gDebuggerExceptionHandlers[Index] == 0) || (gDebuggerExceptionHandlers[Index] == (VOID *)(UINTN)0xEAFFFFFE)) {\r
          // Exception handler contains branch to vector location (jmp $) so no handler\r
          // NOTE: This code assumes vectors are ARM and not Thumb code\r
          Status = RegisterInterruptHandler (Index, NULL);\r
          ASSERT_EFI_ERROR (Status);\r
        } else {\r
          // If the debugger has alread hooked put its vector back\r
          VectorBase[Index] = (UINT32)(UINTN)gDebuggerExceptionHandlers[Index];\r
        }\r
      }\r
    \r
      // Flush Caches since we updated executable stuff\r
      InvalidateInstructionCacheRange ((VOID *)PcdGet32(PcdCpuVectorBaseAddress), Length);\r
\r
      //Note: On ARM processor with the Security Extension, the Vector Table can be located anywhere in the memory.\r
      //      The Vector Base Address Register defines the location\r
      ArmWriteVBar(PcdGet32(PcdCpuVectorBaseAddress));\r
  } else {\r
    // We do not copy the Exception Table at PcdGet32(PcdCpuVectorBaseAddress). We just set Vector Base Address to point into CpuDxe code.\r
    ArmWriteVBar((UINT32)ExceptionHandlersStart);\r
  }\r
\r
  if (FiqEnabled) {\r
    ArmEnableFiq ();\r
  }\r
\r
  if (IrqEnabled) {\r
    // \r
    // Restore interrupt state\r
    //\r
    Status = Cpu->EnableInterrupt (Cpu);\r
  }\r
\r
  return Status;\r
}\r