UefiCpuPkg/Library/SmmCpuFeaturesLib/X64/SmmStmSupport.c

   1 /** @file
   2   SMM STM support functions
   3
   4   Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include <PiSmm.h>
  16 #include <Library/DebugLib.h>
  17
  18 #include "SmmStm.h"
  19
  20 ///
  21 /// Page Table Entry
  22 ///
  23 #define IA32_PG_P                   BIT0
  24 #define IA32_PG_RW                  BIT1
  25 #define IA32_PG_PS                  BIT7
  26
  27 /**
  28
  29   Create 4G page table for STM.
  30   2M PAE page table in X64 version.
  31
  32   @param PageTableBase        The page table base in MSEG
  33
  34 **/
  35 VOID
  36 StmGen4GPageTable (
  37   IN UINTN              PageTableBase
  38   )
  39 {
  40   UINTN                             Index;
  41   UINTN                             SubIndex;
  42   UINT64                            *Pde;
  43   UINT64                            *Pte;
  44   UINT64                            *Pml4;
  45
  46   Pml4 = (UINT64*)(UINTN)PageTableBase;
  47   PageTableBase += SIZE_4KB;
  48   *Pml4 = PageTableBase | IA32_PG_RW | IA32_PG_P;
  49
  50   Pde = (UINT64*)(UINTN)PageTableBase;
  51   PageTableBase += SIZE_4KB;
  52   Pte = (UINT64 *)(UINTN)PageTableBase;
  53
  54   for (Index = 0; Index < 4; Index++) {
  55     *Pde = PageTableBase | IA32_PG_RW | IA32_PG_P;
  56     Pde++;
  57     PageTableBase += SIZE_4KB;
  58
  59     for (SubIndex = 0; SubIndex < SIZE_4KB / sizeof (*Pte); SubIndex++) {
  60       *Pte = (((Index << 9) + SubIndex) << 21) | IA32_PG_PS | IA32_PG_RW | IA32_PG_P;
  61       Pte++;
  62     }
  63   }
  64 }
  65
  66 /**
  67   This is SMM exception handle.
  68   Consumed by STM when exception happen.
  69
  70   @param Context  STM protection exception stack frame
  71
  72   @return the EBX value for STM reference.
  73           EBX = 0: resume SMM guest using register state found on exception stack.
  74           EBX = 1 to 0x0F: EBX contains a BIOS error code which the STM must record in the
  75                            TXT.ERRORCODE register and subsequently reset the system via
  76                            TXT.CMD.SYS_RESET. The value of the TXT.ERRORCODE register is calculated as
  77                            follows: TXT.ERRORCODE = (EBX & 0x0F) | STM_CRASH_BIOS_PANIC
  78           EBX = 0x10 to 0xFFFFFFFF - reserved, do not use.
  79
  80 **/
  81 UINT32
  82 EFIAPI
  83 SmmStmExceptionHandler (
  84   IN OUT STM_PROTECTION_EXCEPTION_STACK_FRAME Context
  85   )
  86 {
  87   // TBD - SmmStmExceptionHandler, record information
  88   DEBUG ((DEBUG_ERROR, "SmmStmExceptionHandler ...\n"));
  89   //
  90   // Skip this instruction and continue;
  91   //
  92   Context.X64StackFrame->Rip += Context.X64StackFrame->VmcsExitInstructionLength;
  93
  94   return 0;
  95 }