UefiCpuPkg/PiSmmCpu: Restrict access per PcdCpuSmmRestrictedMemoryAccess

[mirror_edk2.git] / UefiCpuPkg / PiSmmCpuDxeSmm / Ia32 / PageTbl.c

/** @file\r
Page table manipulation functions for IA-32 processors\r
\r
Copyright (c) 2009 - 2019, Intel Corporation. All rights reserved.<BR>\r
Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>\r
\r
SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include "PiSmmCpuDxeSmm.h"\r
\r
/**\r
  Disable CET.\r
**/\r
VOID\r
EFIAPI\r
DisableCet (\r
  VOID\r
  );\r
\r
/**\r
  Enable CET.\r
**/\r
VOID\r
EFIAPI\r
EnableCet (\r
  VOID\r
  );\r
\r
/**\r
  Create PageTable for SMM use.\r
\r
  @return     PageTable Address\r
\r
**/\r
UINT32\r
SmmInitPageTable (\r
  VOID\r
  )\r
{\r
  UINTN                             PageFaultHandlerHookAddress;\r
  IA32_IDT_GATE_DESCRIPTOR          *IdtEntry;\r
  EFI_STATUS                        Status;\r
\r
  //\r
  // Initialize spin lock\r
  //\r
  InitializeSpinLock (mPFLock);\r
\r
  mPhysicalAddressBits = 32;\r
\r
  if (FeaturePcdGet (PcdCpuSmmProfileEnable) ||\r
      HEAP_GUARD_NONSTOP_MODE ||\r
      NULL_DETECTION_NONSTOP_MODE) {\r
    //\r
    // Set own Page Fault entry instead of the default one, because SMM Profile\r
    // feature depends on IRET instruction to do Single Step\r
    //\r
    PageFaultHandlerHookAddress = (UINTN)PageFaultIdtHandlerSmmProfile;\r
    IdtEntry  = (IA32_IDT_GATE_DESCRIPTOR *) gcSmiIdtr.Base;\r
    IdtEntry += EXCEPT_IA32_PAGE_FAULT;\r
    IdtEntry->Bits.OffsetLow      = (UINT16)PageFaultHandlerHookAddress;\r
    IdtEntry->Bits.Reserved_0     = 0;\r
    IdtEntry->Bits.GateType       = IA32_IDT_GATE_TYPE_INTERRUPT_32;\r
    IdtEntry->Bits.OffsetHigh     = (UINT16)(PageFaultHandlerHookAddress >> 16);\r
  } else {\r
    //\r
    // Register SMM Page Fault Handler\r
    //\r
    Status = SmmRegisterExceptionHandler (&mSmmCpuService, EXCEPT_IA32_PAGE_FAULT, SmiPFHandler);\r
    ASSERT_EFI_ERROR (Status);\r
  }\r
\r
  //\r
  // Additional SMM IDT initialization for SMM stack guard\r
  //\r
  if (FeaturePcdGet (PcdCpuSmmStackGuard)) {\r
    InitializeIDTSmmStackGuard ();\r
  }\r
  return Gen4GPageTable (TRUE);\r
}\r
\r
/**\r
  Page Fault handler for SMM use.\r
\r
**/\r
VOID\r
SmiDefaultPFHandler (\r
  VOID\r
  )\r
{\r
  CpuDeadLoop ();\r
}\r
\r
/**\r
  ThePage Fault handler wrapper for SMM use.\r
\r
  @param  InterruptType    Defines the type of interrupt or exception that\r
                           occurred on the processor.This parameter is processor architecture specific.\r
  @param  SystemContext    A pointer to the processor context when\r
                           the interrupt occurred on the processor.\r
**/\r
VOID\r
EFIAPI\r
SmiPFHandler (\r
  IN EFI_EXCEPTION_TYPE   InterruptType,\r
  IN EFI_SYSTEM_CONTEXT   SystemContext\r
  )\r
{\r
  UINTN             PFAddress;\r
  UINTN             GuardPageAddress;\r
  UINTN             CpuIndex;\r
\r
  ASSERT (InterruptType == EXCEPT_IA32_PAGE_FAULT);\r
\r
  AcquireSpinLock (mPFLock);\r
\r
  PFAddress = AsmReadCr2 ();\r
\r
  //\r
  // If a page fault occurs in SMRAM range, it might be in a SMM stack guard page,\r
  // or SMM page protection violation.\r
  //\r
  if ((PFAddress >= mCpuHotPlugData.SmrrBase) &&\r
      (PFAddress < (mCpuHotPlugData.SmrrBase + mCpuHotPlugData.SmrrSize))) {\r
    DumpCpuContext (InterruptType, SystemContext);\r
    CpuIndex = GetCpuIndex ();\r
    GuardPageAddress = (mSmmStackArrayBase + EFI_PAGE_SIZE + CpuIndex * mSmmStackSize);\r
    if ((FeaturePcdGet (PcdCpuSmmStackGuard)) &&\r
        (PFAddress >= GuardPageAddress) &&\r
        (PFAddress < (GuardPageAddress + EFI_PAGE_SIZE))) {\r
      DEBUG ((DEBUG_ERROR, "SMM stack overflow!\n"));\r
    } else {\r
      if ((SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_ID) != 0) {\r
        DEBUG ((DEBUG_ERROR, "SMM exception at execution (0x%x)\n", PFAddress));\r
        DEBUG_CODE (\r
          DumpModuleInfoByIp (*(UINTN *)(UINTN)SystemContext.SystemContextIa32->Esp);\r
        );\r
      } else {\r
        DEBUG ((DEBUG_ERROR, "SMM exception at access (0x%x)\n", PFAddress));\r
        DEBUG_CODE (\r
          DumpModuleInfoByIp ((UINTN)SystemContext.SystemContextIa32->Eip);\r
        );\r
      }\r
\r
      if (HEAP_GUARD_NONSTOP_MODE) {\r
        GuardPagePFHandler (SystemContext.SystemContextIa32->ExceptionData);\r
        goto Exit;\r
      }\r
    }\r
    CpuDeadLoop ();\r
    goto Exit;\r
  }\r
\r
  //\r
  // If a page fault occurs in non-SMRAM range.\r
  //\r
  if ((PFAddress < mCpuHotPlugData.SmrrBase) ||\r
      (PFAddress >= mCpuHotPlugData.SmrrBase + mCpuHotPlugData.SmrrSize)) {\r
    if ((SystemContext.SystemContextIa32->ExceptionData & IA32_PF_EC_ID) != 0) {\r
      DumpCpuContext (InterruptType, SystemContext);\r
      DEBUG ((DEBUG_ERROR, "Code executed on IP(0x%x) out of SMM range after SMM is locked!\n", PFAddress));\r
      DEBUG_CODE (\r
        DumpModuleInfoByIp (*(UINTN *)(UINTN)SystemContext.SystemContextIa32->Esp);\r
      );\r
      CpuDeadLoop ();\r
      goto Exit;\r
    }\r
\r
    //\r
    // If NULL pointer was just accessed\r
    //\r
    if ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT1) != 0 &&\r
        (PFAddress < EFI_PAGE_SIZE)) {\r
      DumpCpuContext (InterruptType, SystemContext);\r
      DEBUG ((DEBUG_ERROR, "!!! NULL pointer access !!!\n"));\r
      DEBUG_CODE (\r
        DumpModuleInfoByIp ((UINTN)SystemContext.SystemContextIa32->Eip);\r
      );\r
\r
      if (NULL_DETECTION_NONSTOP_MODE) {\r
        GuardPagePFHandler (SystemContext.SystemContextIa32->ExceptionData);\r
        goto Exit;\r
      }\r
\r
      CpuDeadLoop ();\r
      goto Exit;\r
    }\r
\r
    if (IsSmmCommBufferForbiddenAddress (PFAddress)) {\r
      DumpCpuContext (InterruptType, SystemContext);\r
      DEBUG ((DEBUG_ERROR, "Access SMM communication forbidden address (0x%x)!\n", PFAddress));\r
      DEBUG_CODE (\r
        DumpModuleInfoByIp ((UINTN)SystemContext.SystemContextIa32->Eip);\r
      );\r
      CpuDeadLoop ();\r
      goto Exit;\r
    }\r
  }\r
\r
  if (FeaturePcdGet (PcdCpuSmmProfileEnable)) {\r
    SmmProfilePFHandler (\r
      SystemContext.SystemContextIa32->Eip,\r
      SystemContext.SystemContextIa32->ExceptionData\r
      );\r
  } else {\r
    DumpCpuContext (InterruptType, SystemContext);\r
    SmiDefaultPFHandler ();\r
  }\r
\r
Exit:\r
  ReleaseSpinLock (mPFLock);\r
}\r
\r
/**\r
  This function sets memory attribute for page table.\r
**/\r
VOID\r
SetPageTableAttributes (\r
  VOID\r
  )\r
{\r
  UINTN                 Index2;\r
  UINTN                 Index3;\r
  UINT64                *L1PageTable;\r
  UINT64                *L2PageTable;\r
  UINT64                *L3PageTable;\r
  BOOLEAN               IsSplitted;\r
  BOOLEAN               PageTableSplitted;\r
  BOOLEAN               CetEnabled;\r
\r
  //\r
  // Don't mark page table to read-only if heap guard is enabled.\r
  //\r
  //      BIT2: SMM page guard enabled\r
  //      BIT3: SMM pool guard enabled\r
  //\r
  if ((PcdGet8 (PcdHeapGuardPropertyMask) & (BIT3 | BIT2)) != 0) {\r
    DEBUG ((DEBUG_INFO, "Don't mark page table to read-only as heap guard is enabled\n"));\r
    return ;\r
  }\r
\r
  //\r
  // Don't mark page table to read-only if SMM profile is enabled.\r
  //\r
  if (FeaturePcdGet (PcdCpuSmmProfileEnable)) {\r
    DEBUG ((DEBUG_INFO, "Don't mark page table to read-only as SMM profile is enabled\n"));\r
    return ;\r
  }\r
\r
  DEBUG ((DEBUG_INFO, "SetPageTableAttributes\n"));\r
\r
  //\r
  // Disable write protection, because we need mark page table to be write protected.\r
  // We need *write* page table memory, to mark itself to be *read only*.\r
  //\r
  CetEnabled = ((AsmReadCr4() & CR4_CET_ENABLE) != 0) ? TRUE : FALSE;\r
  if (CetEnabled) {\r
    //\r
    // CET must be disabled if WP is disabled.\r
    //\r
    DisableCet();\r
  }\r
  AsmWriteCr0 (AsmReadCr0() & ~CR0_WP);\r
\r
  do {\r
    DEBUG ((DEBUG_INFO, "Start...\n"));\r
    PageTableSplitted = FALSE;\r
\r
    L3PageTable = (UINT64 *)GetPageTableBase ();\r
\r
    SmmSetMemoryAttributesEx ((EFI_PHYSICAL_ADDRESS)(UINTN)L3PageTable, SIZE_4KB, EFI_MEMORY_RO, &IsSplitted);\r
    PageTableSplitted = (PageTableSplitted || IsSplitted);\r
\r
    for (Index3 = 0; Index3 < 4; Index3++) {\r
      L2PageTable = (UINT64 *)(UINTN)(L3PageTable[Index3] & ~mAddressEncMask & PAGING_4K_ADDRESS_MASK_64);\r
      if (L2PageTable == NULL) {\r
        continue;\r
      }\r
\r
      SmmSetMemoryAttributesEx ((EFI_PHYSICAL_ADDRESS)(UINTN)L2PageTable, SIZE_4KB, EFI_MEMORY_RO, &IsSplitted);\r
      PageTableSplitted = (PageTableSplitted || IsSplitted);\r
\r
      for (Index2 = 0; Index2 < SIZE_4KB/sizeof(UINT64); Index2++) {\r
        if ((L2PageTable[Index2] & IA32_PG_PS) != 0) {\r
          // 2M\r
          continue;\r
        }\r
        L1PageTable = (UINT64 *)(UINTN)(L2PageTable[Index2] & ~mAddressEncMask & PAGING_4K_ADDRESS_MASK_64);\r
        if (L1PageTable == NULL) {\r
          continue;\r
        }\r
        SmmSetMemoryAttributesEx ((EFI_PHYSICAL_ADDRESS)(UINTN)L1PageTable, SIZE_4KB, EFI_MEMORY_RO, &IsSplitted);\r
        PageTableSplitted = (PageTableSplitted || IsSplitted);\r
      }\r
    }\r
  } while (PageTableSplitted);\r
\r
  //\r
  // Enable write protection, after page table updated.\r
  //\r
  AsmWriteCr0 (AsmReadCr0() | CR0_WP);\r
  if (CetEnabled) {\r
    //\r
    // re-enable CET.\r
    //\r
    EnableCet();\r
  }\r
\r
  return ;\r
}\r
\r
/**\r
  This function returns with no action for 32 bit.\r
\r
  @param[out]  *Cr2  Pointer to variable to hold CR2 register value.\r
**/\r
VOID\r
SaveCr2 (\r
  OUT UINTN  *Cr2\r
  )\r
{\r
  return ;\r
}\r
\r
/**\r
  This function returns with no action for 32 bit.\r
\r
  @param[in]  Cr2  Value to write into CR2 register.\r
**/\r
VOID\r
RestoreCr2 (\r
  IN UINTN  Cr2\r
  )\r
{\r
  return ;\r
}\r
\r
/**\r
  Return whether access to non-SMRAM is restricted.\r
\r
  @retval TRUE  Access to non-SMRAM is restricted.\r
  @retval FALSE Access to non-SMRAM is not restricted.\r
*/\r
BOOLEAN\r
IsRestrictedMemoryAccess (\r
  VOID\r
  )\r
{\r
  return TRUE;\r
}\r