system76-edk2/UefiCpuPkg/Library/CpuExceptionHandlerLib/PeiCpuException.c

/** @file
  CPU exception handler library implementation for PEIM module.

Copyright (c) 2016 - 2022, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <PiPei.h>
#include "CpuExceptionCommon.h"
#include <Library/DebugLib.h>
#include <Library/HobLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/PcdLib.h>

CONST UINTN  mDoFarReturnFlag = 0;

typedef struct {
  UINT8                     ExceptionStubHeader[HOOKAFTER_STUB_SIZE];
  EXCEPTION_HANDLER_DATA    *ExceptionHandlerData;
} EXCEPTION0_STUB_HEADER;

/**
  Get exception handler data pointer from IDT[0].

  The exception #0 stub header is duplicated in an allocated pool with extra 4-byte/8-byte to store the
  exception handler data. The new allocated memory layout follows structure EXCEPTION0_STUB_HEADER.
  The code assumes that all processors uses the same exception handler for #0 exception.

  @return  pointer to exception handler data.
**/
EXCEPTION_HANDLER_DATA *
GetExceptionHandlerData (
  VOID
  )
{
  IA32_DESCRIPTOR           IdtDescriptor;
  IA32_IDT_GATE_DESCRIPTOR  *IdtTable;
  EXCEPTION0_STUB_HEADER    *Exception0StubHeader;

  AsmReadIdtr (&IdtDescriptor);
  IdtTable = (IA32_IDT_GATE_DESCRIPTOR *)IdtDescriptor.Base;

  Exception0StubHeader = (EXCEPTION0_STUB_HEADER *)ArchGetIdtHandler (&IdtTable[0]);
  return Exception0StubHeader->ExceptionHandlerData;
}

/**
  Set exception handler data pointer to IDT[0].

  The exception #0 stub header is duplicated in an allocated pool with extra 4-byte/8-byte to store the
  exception handler data. The new allocated memory layout follows structure EXCEPTION0_STUB_HEADER.
  The code assumes that all processors uses the same exception handler for #0 exception.

  @param ExceptionHandlerData  pointer to exception handler data.
**/
VOID
SetExceptionHandlerData (
  IN EXCEPTION_HANDLER_DATA  *ExceptionHandlerData
  )
{
  EXCEPTION0_STUB_HEADER    *Exception0StubHeader;
  IA32_DESCRIPTOR           IdtDescriptor;
  IA32_IDT_GATE_DESCRIPTOR  *IdtTable;

  //
  // Duplicate the exception #0 stub header in pool and cache the ExceptionHandlerData just after the stub header.
  // So AP can get the ExceptionHandlerData by reading the IDT[0].
  //
  AsmReadIdtr (&IdtDescriptor);
  IdtTable = (IA32_IDT_GATE_DESCRIPTOR *)IdtDescriptor.Base;

  Exception0StubHeader = AllocatePool (sizeof (*Exception0StubHeader));
  ASSERT (Exception0StubHeader != NULL);
  CopyMem (
    Exception0StubHeader->ExceptionStubHeader,
    (VOID *)ArchGetIdtHandler (&IdtTable[0]),
    sizeof (Exception0StubHeader->ExceptionStubHeader)
    );
  Exception0StubHeader->ExceptionHandlerData = ExceptionHandlerData;
  ArchUpdateIdtEntry (&IdtTable[0], (UINTN)Exception0StubHeader->ExceptionStubHeader);
}

/**
  Common exception handler.

  @param ExceptionType  Exception type.
  @param SystemContext  Pointer to EFI_SYSTEM_CONTEXT.
**/
VOID
EFIAPI
CommonExceptionHandler (
  IN EFI_EXCEPTION_TYPE  ExceptionType,
  IN EFI_SYSTEM_CONTEXT  SystemContext
  )
{
  EXCEPTION_HANDLER_DATA  *ExceptionHandlerData;

  ExceptionHandlerData = GetExceptionHandlerData ();
  CommonExceptionHandlerWorker (ExceptionType, SystemContext, ExceptionHandlerData);
}

/**
  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.
  Note: Before invoking this API, caller must allocate memory for IDT table and load
        IDTR by AsmWriteIdtr().

  @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
  )
{
  EFI_STATUS              Status;
  EXCEPTION_HANDLER_DATA  *ExceptionHandlerData;
  RESERVED_VECTORS_DATA   *ReservedVectors;

  ReservedVectors = AllocatePool (sizeof (RESERVED_VECTORS_DATA) * CPU_EXCEPTION_NUM);
  ASSERT (ReservedVectors != NULL);

  ExceptionHandlerData = AllocatePool (sizeof (EXCEPTION_HANDLER_DATA));
  ASSERT (ExceptionHandlerData != NULL);
  ExceptionHandlerData->IdtEntryCount            = CPU_EXCEPTION_NUM;
  ExceptionHandlerData->ReservedVectors          = ReservedVectors;
  ExceptionHandlerData->ExternalInterruptHandler = NULL;
  InitializeSpinLock (&ExceptionHandlerData->DisplayMessageSpinLock);

  Status = InitializeCpuExceptionHandlersWorker (VectorInfo, ExceptionHandlerData);
  if (EFI_ERROR (Status)) {
    FreePool (ReservedVectors);
    FreePool (ExceptionHandlerData);
    return Status;
  }

  SetExceptionHandlerData (ExceptionHandlerData);
  return EFI_SUCCESS;
}

/**
  Initializes all CPU exceptions entries with optional extra initializations.

  By default, this method should include all functionalities implemented by
  InitializeCpuExceptionHandlers(), plus extra initialization works, if any.
  This could be done by calling InitializeCpuExceptionHandlers() directly
  in this method besides the extra works.

  InitData is optional and its use and content are processor arch dependent.
  The typical usage of it is to convey resources which have to be reserved
  elsewhere and are necessary for the extra initializations of exception.

  @param[in]  VectorInfo    Pointer to reserved vector list.
  @param[in]  InitData      Pointer to data optional for extra initializations
                            of exception.

  @retval EFI_SUCCESS             The exceptions have been successfully
                                  initialized.
  @retval EFI_INVALID_PARAMETER   VectorInfo or InitData contains invalid
                                  content.

**/
EFI_STATUS
EFIAPI
InitializeCpuExceptionHandlersEx (
  IN EFI_VECTOR_HANDOFF_INFO  *VectorInfo OPTIONAL,
  IN CPU_EXCEPTION_INIT_DATA  *InitData OPTIONAL
  )
{
  EFI_STATUS  Status;

  //
  // To avoid repeat initialization of default handlers, the caller should pass
  // an extended init data with InitDefaultHandlers set to FALSE. There's no
  // need to call this method to just initialize default handlers. Call non-ex
  // version instead; or this method must be implemented as a simple wrapper of
  // non-ex version of it, if this version has to be called.
  //
  if ((InitData == NULL) || InitData->Ia32.InitDefaultHandlers) {
    Status = InitializeCpuExceptionHandlers (VectorInfo);
  } else {
    Status = EFI_SUCCESS;
  }

  if (!EFI_ERROR (Status)) {
    //
    // Initializing stack switch is only necessary for Stack Guard functionality.
    //
    if (PcdGetBool (PcdCpuStackGuard) && (InitData != NULL)) {
      Status = ArchSetupExceptionStack (InitData);
    }
  }

  return Status;
}