ArmPkg: ARM/AArch64 implementation of CpuExceptionHandlerLib

Introduce ARM and AArch64 instances of the CpuExceptionHandlerLib which
provides exception handling and registration of handlers regardless of
execution phase.

Two variants of the ArmExceptionLib are provided: one where exception
handlers reside within the module (meeting appropriate architectural
alignment requirements for the vector table) and another one that will
relocate a copy of thee xception handlers to an address specified by
PcdCpuVectorBaseAddress. The ArmRelocateExceptionLib is intended for use
in cases where ArmExceptionLib is too large for the application
(uncompressed XIP images) as driven by the vector table alignment padding.

The AArch64 build of this library supports execution at EL1, EL2, and EL3
exception levels.

Tested on ARM, and AArch64 with SEC, DXE Core, and CpuDxe modules.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Eugene Cohen <eugene@hp.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

1 files changed, 320 insertions, 0 deletions

diff --git a/ArmPkg/Library/ArmExceptionLib/ArmExceptionLib.c b/ArmPkg/Library/ArmExceptionLib/ArmExceptionLib.c
new file mode 100644
index 0000000..5977a3e
--- /dev/null
+++ b/ArmPkg/Library/ArmExceptionLib/ArmExceptionLib.c
@@ -0,0 +1,320 @@
+/* @file

+*  Main file supporting the SEC Phase for Versatile Express

+*

+*  Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>

+*  Copyright (c) 2011-2014, ARM Limited. All rights reserved.

+*  Copyright (c) 2016 HP Development Company, L.P.

+*

+*  This program and the accompanying materials

+*  are licensed and made available under the terms and conditions of the BSD License

+*  which accompanies this distribution.  The full text of the license may be found at

+*  http://opensource.org/licenses/bsd-license.php

+*

+*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,

+*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

+*

+**/

+

+#include <Uefi.h>

+#include <Library/CpuExceptionHandlerLib.h>

+

+#include <Library/ArmLib.h>

+#include <Library/PcdLib.h>

+#include <Library/CacheMaintenanceLib.h>

+#include <Library/BaseLib.h>

+#include <Library/BaseMemoryLib.h>

+#include <Library/DebugLib.h>

+#include <Library/DefaultExceptionHandlerLib.h>

+

+RETURN_STATUS

+CopyExceptionHandlers(

+  IN  PHYSICAL_ADDRESS        BaseAddress

+  );

+

+EFI_STATUS

+EFIAPI

+RegisterExceptionHandler(

+  IN EFI_EXCEPTION_TYPE            ExceptionType,

+  IN EFI_CPU_INTERRUPT_HANDLER     InterruptHandler

+  );

+

+VOID

+ExceptionHandlersStart(

+  VOID

+  );

+

+VOID

+ExceptionHandlersEnd(

+  VOID

+  );

+

+RETURN_STATUS ArchVectorConfig(

+  IN  UINTN       VectorBaseAddress

+  );

+

+// these globals are provided by the architecture specific source (Arm or AArch64)

+extern UINTN                    gMaxExceptionNumber;

+extern EFI_EXCEPTION_CALLBACK   gExceptionHandlers[];

+extern EFI_EXCEPTION_CALLBACK   gDebuggerExceptionHandlers[];

+extern PHYSICAL_ADDRESS         gExceptionVectorAlignmentMask;

+extern UINTN                    gDebuggerNoHandlerValue;

+

+// A compiler flag adjusts the compilation of this library to a variant where

+// the vectors are relocated (copied) to another location versus using the

+// vectors in-place.  Since this effects an assembly .align directive we must

+// address this at library build time.  Since this affects the build of the

+// library we cannot represent this in a PCD since PCDs are evaluated on

+// a per-module basis.

+#if defined(ARM_RELOCATE_VECTORS)

+BOOLEAN gArmRelocateVectorTable = TRUE;

+#else

+BOOLEAN gArmRelocateVectorTable = FALSE;

+#endif

+

+

+/**

+Initializes all CPU exceptions entries and provides the default exception handlers.

+

+Caller should try to get an array of interrupt and/or exception vectors that are in use and need to

+persist by EFI_VECTOR_HANDOFF_INFO defined in PI 1.3 specification.

+If caller cannot get reserved vector list or it does not exists, set VectorInfo to NULL.

+If VectorInfo is not NULL, the exception vectors will be initialized per vector attribute accordingly.

+

+@param[in]  VectorInfo    Pointer to reserved vector list.

+

+@retval EFI_SUCCESS           CPU Exception Entries have been successfully initialized

+with default exception handlers.

+@retval EFI_INVALID_PARAMETER VectorInfo includes the invalid content if VectorInfo is not NULL.

+@retval EFI_UNSUPPORTED       This function is not supported.

+

+**/

+EFI_STATUS

+EFIAPI

+InitializeCpuExceptionHandlers(

+  IN EFI_VECTOR_HANDOFF_INFO       *VectorInfo OPTIONAL

+  )

+{

+  RETURN_STATUS     Status;

+  UINTN             VectorBase;

+

+  Status = EFI_SUCCESS;

+

+  // if we are requested to copy exceptin handlers to another location

+  if (gArmRelocateVectorTable) {

+

+    VectorBase = PcdGet32(PcdCpuVectorBaseAddress);

+    Status = CopyExceptionHandlers(VectorBase);

+

+  }

+  else { // use VBAR to point to where our exception handlers are

+

+    // The vector table must be aligned for the architecture.  If this

+    // assertion fails ensure the appropriate FFS alignment is in effect,

+    // which can be accomplished by ensuring the proper Align=X statement

+    // in the platform packaging rules.  For ARM Align=32 is required and

+    // for AArch64 Align=4K is required.  Align=Auto can be used but this

+    // is known to cause an issue with populating the reset vector area

+    // for encapsulated FVs.

+    ASSERT(((UINTN)ExceptionHandlersStart & gExceptionVectorAlignmentMask) == 0);

+

+    // We do not copy the Exception Table at PcdGet32(PcdCpuVectorBaseAddress). We just set Vector

+    // Base Address to point into CpuDxe code.

+    VectorBase = (UINTN)ExceptionHandlersStart;

+

+    Status = RETURN_SUCCESS;

+  }

+

+  if (!RETURN_ERROR(Status)) {

+    // call the architecture-specific routine to prepare for the new vector

+    // configuration to take effect

+    ArchVectorConfig(VectorBase);

+

+    ArmWriteVBar(VectorBase);

+  }

+

+  return RETURN_SUCCESS;

+}

+

+/**

+Copies exception handlers to the speciifed address.

+

+Caller should try to get an array of interrupt and/or exception vectors that are in use and need to

+persist by EFI_VECTOR_HANDOFF_INFO defined in PI 1.3 specification.

+If caller cannot get reserved vector list or it does not exists, set VectorInfo to NULL.

+If VectorInfo is not NULL, the exception vectors will be initialized per vector attribute accordingly.

+

+@param[in]  VectorInfo    Pointer to reserved vector list.

+

+@retval EFI_SUCCESS           CPU Exception Entries have been successfully initialized

+with default exception handlers.

+@retval EFI_INVALID_PARAMETER VectorInfo includes the invalid content if VectorInfo is not NULL.

+@retval EFI_UNSUPPORTED       This function is not supported.

+

+**/

+RETURN_STATUS

+CopyExceptionHandlers(

+  IN  PHYSICAL_ADDRESS        BaseAddress

+  )

+{

+  RETURN_STATUS        Status;

+  UINTN                Length;

+  UINTN                Index;

+  UINT32               *VectorBase;

+

+  // ensure that the destination value specifies an address meeting the vector alignment requirements

+  ASSERT ((BaseAddress & gExceptionVectorAlignmentMask) == 0);

+

+  //

+  // Copy an implementation of the exception vectors to PcdCpuVectorBaseAddress.

+  //

+  Length = (UINTN)ExceptionHandlersEnd - (UINTN)ExceptionHandlersStart;

+

+  VectorBase = (UINT32 *)(UINTN)BaseAddress;

+

+  if (FeaturePcdGet(PcdDebuggerExceptionSupport) == TRUE) {

+    // Save existing vector table, in case debugger is already hooked in

+    CopyMem((VOID *)gDebuggerExceptionHandlers, (VOID *)VectorBase, sizeof (EFI_EXCEPTION_CALLBACK)* (gMaxExceptionNumber+1));

+  }

+

+  // Copy our assembly code into the page that contains the exception vectors.

+  CopyMem((VOID *)VectorBase, (VOID *)ExceptionHandlersStart, Length);

+

+  //

+  // Initialize the C entry points for interrupts

+  //

+  for (Index = 0; Index <= gMaxExceptionNumber; Index++) {

+    if (!FeaturePcdGet(PcdDebuggerExceptionSupport) ||

+      (gDebuggerExceptionHandlers[Index] == 0) || (gDebuggerExceptionHandlers[Index] == (VOID *)gDebuggerNoHandlerValue)) {

+

+      Status = RegisterExceptionHandler(Index, NULL);

+      ASSERT_EFI_ERROR(Status);

+    }

+    else {

+      // If the debugger has already hooked put its vector back

+      VectorBase[Index] = (UINT32)(UINTN)gDebuggerExceptionHandlers[Index];

+    }

+  }

+

+  // Flush Caches since we updated executable stuff

+  InvalidateInstructionCacheRange((VOID *)(UINTN)BaseAddress, Length);

+

+  return RETURN_SUCCESS;

+}

+

+

+/**

+Initializes all CPU interrupt/exceptions entries and provides the default interrupt/exception handlers.

+

+Caller should try to get an array of interrupt and/or exception vectors that are in use and need to

+persist by EFI_VECTOR_HANDOFF_INFO defined in PI 1.3 specification.

+If caller cannot get reserved vector list or it does not exists, set VectorInfo to NULL.

+If VectorInfo is not NULL, the exception vectors will be initialized per vector attribute accordingly.

+

+@param[in]  VectorInfo    Pointer to reserved vector list.

+

+@retval EFI_SUCCESS           All CPU interrupt/exception entries have been successfully initialized

+with default interrupt/exception handlers.

+@retval EFI_INVALID_PARAMETER VectorInfo includes the invalid content if VectorInfo is not NULL.

+@retval EFI_UNSUPPORTED       This function is not supported.

+

+**/

+EFI_STATUS

+EFIAPI

+InitializeCpuInterruptHandlers(

+IN EFI_VECTOR_HANDOFF_INFO       *VectorInfo OPTIONAL

+)

+{

+  // not needed, this is what the CPU driver is for

+  return EFI_UNSUPPORTED;

+}

+

+/**

+Registers a function to be called from the processor exception handler. (On ARM/AArch64 this only

+provides exception handlers, not interrupt handling which is provided through the Hardware Interrupt

+Protocol.)

+

+This function registers and enables the handler specified by ExceptionHandler for a processor

+interrupt or exception type specified by ExceptionType. If ExceptionHandler is NULL, then the

+handler for the processor interrupt or exception type specified by ExceptionType is uninstalled.

+The installed handler is called once for each processor interrupt or exception.

+NOTE: This function should be invoked after InitializeCpuExceptionHandlers() or

+InitializeCpuInterruptHandlers() invoked, otherwise EFI_UNSUPPORTED returned.

+

+@param[in]  ExceptionType     Defines which interrupt or exception to hook.

+@param[in]  ExceptionHandler  A pointer to a function of type EFI_CPU_INTERRUPT_HANDLER that is called

+when a processor interrupt occurs. If this parameter is NULL, then the handler

+will be uninstalled.

+

+@retval EFI_SUCCESS           The handler for the processor interrupt was successfully installed or uninstalled.

+@retval EFI_ALREADY_STARTED   ExceptionHandler is not NULL, and a handler for ExceptionType was

+previously installed.

+@retval EFI_INVALID_PARAMETER ExceptionHandler is NULL, and a handler for ExceptionType was not

+previously installed.

+@retval EFI_UNSUPPORTED       The interrupt specified by ExceptionType is not supported,

+or this function is not supported.

+**/

+RETURN_STATUS

+RegisterCpuInterruptHandler(

+  IN EFI_EXCEPTION_TYPE             ExceptionType,

+  IN EFI_CPU_INTERRUPT_HANDLER      ExceptionHandler

+  ) {

+  if (ExceptionType > gMaxExceptionNumber) {

+    return RETURN_UNSUPPORTED;

+  }

+

+  if ((ExceptionHandler != NULL) && (gExceptionHandlers[ExceptionType] != NULL)) {

+    return RETURN_ALREADY_STARTED;

+  }

+

+  gExceptionHandlers[ExceptionType] = ExceptionHandler;

+

+  return RETURN_SUCCESS;

+}

+

+/**

+Register exception handler.

+

+@param  This                  A pointer to the SMM_CPU_SERVICE_PROTOCOL instance.

+@param  ExceptionType         Defines which interrupt or exception to hook. Type EFI_EXCEPTION_TYPE and

+the valid values for this parameter are defined in EFI_DEBUG_SUPPORT_PROTOCOL

+of the UEFI 2.0 specification.

+@param  InterruptHandler      A pointer to a function of type EFI_CPU_INTERRUPT_HANDLER

+that is called when a processor interrupt occurs.

+If this parameter is NULL, then the handler will be uninstalled.

+

+@retval EFI_SUCCESS           The handler for the processor interrupt was successfully installed or uninstalled.

+@retval EFI_ALREADY_STARTED   InterruptHandler is not NULL, and a handler for InterruptType was previously installed.

+@retval EFI_INVALID_PARAMETER InterruptHandler is NULL, and a handler for InterruptType was not previously installed.

+@retval EFI_UNSUPPORTED       The interrupt specified by InterruptType is not supported.

+

+**/

+EFI_STATUS

+EFIAPI

+RegisterExceptionHandler(

+  IN EFI_EXCEPTION_TYPE            ExceptionType,

+  IN EFI_CPU_INTERRUPT_HANDLER     InterruptHandler

+  )

+{

+  return RegisterCpuInterruptHandler(ExceptionType, InterruptHandler);

+}

+

+VOID

+EFIAPI

+CommonCExceptionHandler(

+  IN     EFI_EXCEPTION_TYPE           ExceptionType,

+  IN OUT EFI_SYSTEM_CONTEXT           SystemContext

+  )

+{

+  if (ExceptionType <= gMaxExceptionNumber) {

+    if (gExceptionHandlers[ExceptionType]) {

+      gExceptionHandlers[ExceptionType](ExceptionType, SystemContext);

+      return;

+    }

+  }

+  else {

+    DEBUG((EFI_D_ERROR, "Unknown exception type %d\n", ExceptionType));

+    ASSERT(FALSE);

+  }

+

+  DefaultExceptionHandler(ExceptionType, SystemContext);

+}