[mirror_edk2.git] / UefiCpuPkg / PiSmmCpuDxeSmm / X64 / SmmProfileArch.c

/** @file\r
X64 processor specific functions to enable SMM profile.\r
\r
Copyright (c) 2012 - 2016, Intel Corporation. All rights reserved.<BR>\r
Copyright (c) 2017, AMD Incorporated. 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 "PiSmmCpuDxeSmm.h"\r
#include "SmmProfileInternal.h"\r
\r
//\r
// Current page index.\r
//\r
UINTN                     mPFPageIndex;\r
\r
//\r
// Pool for dynamically creating page table in page fault handler.\r
//\r
UINT64                    mPFPageBuffer;\r
\r
//\r
// Store the uplink information for each page being used.\r
//\r
UINT64                    *mPFPageUplink[MAX_PF_PAGE_COUNT];\r
\r
/**\r
  Create SMM page table for S3 path.\r
\r
**/\r
VOID\r
InitSmmS3Cr3 (\r
  VOID\r
  )\r
{\r
  EFI_PHYSICAL_ADDRESS              Pages;\r
  UINT64                            *PTEntry;\r
\r
  //\r
  // Generate PAE page table for the first 4GB memory space\r
  //\r
  Pages = Gen4GPageTable (FALSE);\r
\r
  //\r
  // Fill Page-Table-Level4 (PML4) entry\r
  //\r
  PTEntry = (UINT64*)AllocatePageTableMemory (1);\r
  ASSERT (PTEntry != NULL);\r
  *PTEntry = Pages | mAddressEncMask | PAGE_ATTRIBUTE_BITS;\r
  ZeroMem (PTEntry + 1, EFI_PAGE_SIZE - sizeof (*PTEntry));\r
\r
  //\r
  // Return the address of PML4 (to set CR3)\r
  //\r
  mSmmS3ResumeState->SmmS3Cr3 = (UINT32)(UINTN)PTEntry;\r
\r
  return ;\r
}\r
\r
/**\r
  Allocate pages for creating 4KB-page based on 2MB-page when page fault happens.\r
\r
**/\r
VOID\r
InitPagesForPFHandler (\r
  VOID\r
  )\r
{\r
  VOID          *Address;\r
\r
  //\r
  // Pre-Allocate memory for page fault handler\r
  //\r
  Address = NULL;\r
  Address = AllocatePages (MAX_PF_PAGE_COUNT);\r
  ASSERT (Address != NULL);\r
\r
  mPFPageBuffer =  (UINT64)(UINTN) Address;\r
  mPFPageIndex = 0;\r
  ZeroMem ((VOID *) (UINTN) mPFPageBuffer, EFI_PAGE_SIZE * MAX_PF_PAGE_COUNT);\r
  ZeroMem (mPFPageUplink, sizeof (mPFPageUplink));\r
\r
  return;\r
}\r
\r
/**\r
  Allocate one page for creating 4KB-page based on 2MB-page.\r
\r
  @param  Uplink   The address of Page-Directory entry.\r
\r
**/\r
VOID\r
AcquirePage (\r
  UINT64          *Uplink\r
  )\r
{\r
  UINT64          Address;\r
\r
  //\r
  // Get the buffer\r
  //\r
  Address = mPFPageBuffer + EFI_PAGES_TO_SIZE (mPFPageIndex);\r
  ZeroMem ((VOID *) (UINTN) Address, EFI_PAGE_SIZE);\r
\r
  //\r
  // Cut the previous uplink if it exists and wasn't overwritten\r
  //\r
  if ((mPFPageUplink[mPFPageIndex] != NULL) && ((*mPFPageUplink[mPFPageIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK) == Address)) {\r
    *mPFPageUplink[mPFPageIndex] = 0;\r
  }\r
\r
  //\r
  // Link & Record the current uplink\r
  //\r
  *Uplink = Address | mAddressEncMask | PAGE_ATTRIBUTE_BITS;\r
  mPFPageUplink[mPFPageIndex] = Uplink;\r
\r
  mPFPageIndex = (mPFPageIndex + 1) % MAX_PF_PAGE_COUNT;\r
}\r
\r
/**\r
  Update page table to map the memory correctly in order to make the instruction\r
  which caused page fault execute successfully. And it also save the original page\r
  table to be restored in single-step exception.\r
\r
  @param  PageTable           PageTable Address.\r
  @param  PFAddress           The memory address which caused page fault exception.\r
  @param  CpuIndex            The index of the processor.\r
  @param  ErrorCode           The Error code of exception.\r
  @param  IsValidPFAddress    The flag indicates if SMM profile data need be added.\r
\r
**/\r
VOID\r
RestorePageTableAbove4G (\r
  UINT64        *PageTable,\r
  UINT64        PFAddress,\r
  UINTN         CpuIndex,\r
  UINTN         ErrorCode,\r
  BOOLEAN       *IsValidPFAddress\r
  )\r
{\r
  UINTN         PTIndex;\r
  UINT64        Address;\r
  BOOLEAN       Nx;\r
  BOOLEAN       Existed;\r
  UINTN         Index;\r
  UINTN         PFIndex;\r
\r
  ASSERT ((PageTable != NULL) && (IsValidPFAddress != NULL));\r
\r
  //\r
  // If page fault address is 4GB above.\r
  //\r
\r
  //\r
  // Check if page fault address has existed in page table.\r
  // If it exists in page table but page fault is generated,\r
  // there are 2 possible reasons: 1. present flag is set to 0; 2. instruction fetch in protected memory range.\r
  //\r
  Existed = FALSE;\r
  PageTable = (UINT64*)(AsmReadCr3 () & PHYSICAL_ADDRESS_MASK);\r
  PTIndex = BitFieldRead64 (PFAddress, 39, 47);\r
  if ((PageTable[PTIndex] & IA32_PG_P) != 0) {\r
    // PML4E\r
    PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
    PTIndex = BitFieldRead64 (PFAddress, 30, 38);\r
    if ((PageTable[PTIndex] & IA32_PG_P) != 0) {\r
      // PDPTE\r
      PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
      PTIndex = BitFieldRead64 (PFAddress, 21, 29);\r
      // PD\r
      if ((PageTable[PTIndex] & IA32_PG_PS) != 0) {\r
        //\r
        // 2MB page\r
        //\r
        Address = (UINT64)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
        if ((Address & ~((1ull << 21) - 1)) == ((PFAddress & PHYSICAL_ADDRESS_MASK & ~((1ull << 21) - 1)))) {\r
          Existed = TRUE;\r
        }\r
      } else {\r
        //\r
        // 4KB page\r
        //\r
        PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask& PHYSICAL_ADDRESS_MASK);\r
        if (PageTable != 0) {\r
          //\r
          // When there is a valid entry to map to 4KB page, need not create a new entry to map 2MB.\r
          //\r
          PTIndex = BitFieldRead64 (PFAddress, 12, 20);\r
          Address = (UINT64)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
          if ((Address & ~((1ull << 12) - 1)) == (PFAddress & PHYSICAL_ADDRESS_MASK & ~((1ull << 12) - 1))) {\r
            Existed = TRUE;\r
          }\r
        }\r
      }\r
    }\r
  }\r
\r
  //\r
  // If page entry does not existed in page table at all, create a new entry.\r
  //\r
  if (!Existed) {\r
\r
    if (IsAddressValid (PFAddress, &Nx)) {\r
      //\r
      // If page fault address above 4GB is in protected range but it causes a page fault exception,\r
      // Will create a page entry for this page fault address, make page table entry as present/rw and execution-disable.\r
      // this access is not saved into SMM profile data.\r
      //\r
      *IsValidPFAddress = TRUE;\r
    }\r
\r
    //\r
    // Create one entry in page table for page fault address.\r
    //\r
    SmiDefaultPFHandler ();\r
    //\r
    // Find the page table entry created just now.\r
    //\r
    PageTable = (UINT64*)(AsmReadCr3 () & PHYSICAL_ADDRESS_MASK);\r
    PFAddress = AsmReadCr2 ();\r
    // PML4E\r
    PTIndex = BitFieldRead64 (PFAddress, 39, 47);\r
    PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
    // PDPTE\r
    PTIndex = BitFieldRead64 (PFAddress, 30, 38);\r
    PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
    // PD\r
    PTIndex = BitFieldRead64 (PFAddress, 21, 29);\r
    Address = PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK;\r
    //\r
    // Check if 2MB-page entry need be changed to 4KB-page entry.\r
    //\r
    if (IsAddressSplit (Address)) {\r
      AcquirePage (&PageTable[PTIndex]);\r
\r
      // PTE\r
      PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
      for (Index = 0; Index < 512; Index++) {\r
        PageTable[Index] = Address | mAddressEncMask | PAGE_ATTRIBUTE_BITS;\r
        if (!IsAddressValid (Address, &Nx)) {\r
          PageTable[Index] = PageTable[Index] & (INTN)(INT32)(~PAGE_ATTRIBUTE_BITS);\r
        }\r
        if (Nx && mXdSupported) {\r
          PageTable[Index] = PageTable[Index] | IA32_PG_NX;\r
        }\r
        if (Address == (PFAddress & PHYSICAL_ADDRESS_MASK & ~((1ull << 12) - 1))) {\r
          PTIndex = Index;\r
        }\r
        Address += SIZE_4KB;\r
      } // end for PT\r
    } else {\r
      //\r
      // Update 2MB page entry.\r
      //\r
      if (!IsAddressValid (Address, &Nx)) {\r
        //\r
        // Patch to remove present flag and rw flag.\r
        //\r
        PageTable[PTIndex] = PageTable[PTIndex] & (INTN)(INT32)(~PAGE_ATTRIBUTE_BITS);\r
      }\r
      //\r
      // Set XD bit to 1\r
      //\r
      if (Nx && mXdSupported) {\r
        PageTable[PTIndex] = PageTable[PTIndex] | IA32_PG_NX;\r
      }\r
    }\r
  }\r
\r
  //\r
  // Record old entries with non-present status\r
  // Old entries include the memory which instruction is at and the memory which instruction access.\r
  //\r
  //\r
  ASSERT (mPFEntryCount[CpuIndex] < MAX_PF_ENTRY_COUNT);\r
  if (mPFEntryCount[CpuIndex] < MAX_PF_ENTRY_COUNT) {\r
    PFIndex = mPFEntryCount[CpuIndex];\r
    mLastPFEntryValue[CpuIndex][PFIndex]   = PageTable[PTIndex];\r
    mLastPFEntryPointer[CpuIndex][PFIndex] = &PageTable[PTIndex];\r
    mPFEntryCount[CpuIndex]++;\r
  }\r
\r
  //\r
  // Add present flag or clear XD flag to make page fault handler succeed.\r
  //\r
  PageTable[PTIndex] |= (UINT64)(PAGE_ATTRIBUTE_BITS);\r
  if ((ErrorCode & IA32_PF_EC_ID) != 0) {\r
    //\r
    // If page fault is caused by instruction fetch, clear XD bit in the entry.\r
    //\r
    PageTable[PTIndex] &= ~IA32_PG_NX;\r
  }\r
\r
  return;\r
}\r
\r
/**\r
  Clear TF in FLAGS.\r
\r
  @param  SystemContext    A pointer to the processor context when\r
                           the interrupt occurred on the processor.\r
\r
**/\r
VOID\r
ClearTrapFlag (\r
  IN OUT EFI_SYSTEM_CONTEXT   SystemContext\r
  )\r
{\r
  SystemContext.SystemContextX64->Rflags &= (UINTN) ~BIT8;\r
}\r
Commit	Line	Data
	1	/** @file\r
	2	X64 processor specific functions to enable SMM profile.\r
	3	\r
	4	Copyright (c) 2012 - 2016, Intel Corporation. All rights reserved.<BR>\r
	5	Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>\r
	6	\r
	7	This program and the accompanying materials\r
	8	are licensed and made available under the terms and conditions of the BSD License\r
	9	which accompanies this distribution. The full text of the license may be found at\r
	10	http://opensource.org/licenses/bsd-license.php\r
	11	\r
	12	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	13	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	14	\r
	15	**/\r
	16	\r
	17	#include "PiSmmCpuDxeSmm.h"\r
	18	#include "SmmProfileInternal.h"\r
	19	\r
	20	//\r
	21	// Current page index.\r
	22	//\r
	23	UINTN mPFPageIndex;\r
	24	\r
	25	//\r
	26	// Pool for dynamically creating page table in page fault handler.\r
	27	//\r
	28	UINT64 mPFPageBuffer;\r
	29	\r
	30	//\r
	31	// Store the uplink information for each page being used.\r
	32	//\r
	33	UINT64 *mPFPageUplink[MAX_PF_PAGE_COUNT];\r
	34	\r
	35	/**\r
	36	Create SMM page table for S3 path.\r
	37	\r
	38	**/\r
	39	VOID\r
	40	InitSmmS3Cr3 (\r
	41	VOID\r
	42	)\r
	43	{\r
	44	EFI_PHYSICAL_ADDRESS Pages;\r
	45	UINT64 *PTEntry;\r
	46	\r
	47	//\r
	48	// Generate PAE page table for the first 4GB memory space\r
	49	//\r
	50	Pages = Gen4GPageTable (FALSE);\r
	51	\r
	52	//\r
	53	// Fill Page-Table-Level4 (PML4) entry\r
	54	//\r
	55	PTEntry = (UINT64*)AllocatePageTableMemory (1);\r
	56	ASSERT (PTEntry != NULL);\r
	57	*PTEntry = Pages \| mAddressEncMask \| PAGE_ATTRIBUTE_BITS;\r
	58	ZeroMem (PTEntry + 1, EFI_PAGE_SIZE - sizeof (*PTEntry));\r
	59	\r
	60	//\r
	61	// Return the address of PML4 (to set CR3)\r
	62	//\r
	63	mSmmS3ResumeState->SmmS3Cr3 = (UINT32)(UINTN)PTEntry;\r
	64	\r
	65	return ;\r
	66	}\r
	67	\r
	68	/**\r
	69	Allocate pages for creating 4KB-page based on 2MB-page when page fault happens.\r
	70	\r
	71	**/\r
	72	VOID\r
	73	InitPagesForPFHandler (\r
	74	VOID\r
	75	)\r
	76	{\r
	77	VOID *Address;\r
	78	\r
	79	//\r
	80	// Pre-Allocate memory for page fault handler\r
	81	//\r
	82	Address = NULL;\r
	83	Address = AllocatePages (MAX_PF_PAGE_COUNT);\r
	84	ASSERT (Address != NULL);\r
	85	\r
	86	mPFPageBuffer = (UINT64)(UINTN) Address;\r
	87	mPFPageIndex = 0;\r
	88	ZeroMem ((VOID ) (UINTN) mPFPageBuffer, EFI_PAGE_SIZE MAX_PF_PAGE_COUNT);\r
	89	ZeroMem (mPFPageUplink, sizeof (mPFPageUplink));\r
	90	\r
	91	return;\r
	92	}\r
	93	\r
	94	/**\r
	95	Allocate one page for creating 4KB-page based on 2MB-page.\r
	96	\r
	97	@param Uplink The address of Page-Directory entry.\r
	98	\r
	99	**/\r
	100	VOID\r
	101	AcquirePage (\r
	102	UINT64 *Uplink\r
	103	)\r
	104	{\r
	105	UINT64 Address;\r
	106	\r
	107	//\r
	108	// Get the buffer\r
	109	//\r
	110	Address = mPFPageBuffer + EFI_PAGES_TO_SIZE (mPFPageIndex);\r
	111	ZeroMem ((VOID *) (UINTN) Address, EFI_PAGE_SIZE);\r
	112	\r
	113	//\r
	114	// Cut the previous uplink if it exists and wasn't overwritten\r
	115	//\r
	116	if ((mPFPageUplink[mPFPageIndex] != NULL) && ((*mPFPageUplink[mPFPageIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK) == Address)) {\r
	117	*mPFPageUplink[mPFPageIndex] = 0;\r
	118	}\r
	119	\r
	120	//\r
	121	// Link & Record the current uplink\r
	122	//\r
	123	*Uplink = Address \| mAddressEncMask \| PAGE_ATTRIBUTE_BITS;\r
	124	mPFPageUplink[mPFPageIndex] = Uplink;\r
	125	\r
	126	mPFPageIndex = (mPFPageIndex + 1) % MAX_PF_PAGE_COUNT;\r
	127	}\r
	128	\r
	129	/**\r
	130	Update page table to map the memory correctly in order to make the instruction\r
	131	which caused page fault execute successfully. And it also save the original page\r
	132	table to be restored in single-step exception.\r
	133	\r
	134	@param PageTable PageTable Address.\r
	135	@param PFAddress The memory address which caused page fault exception.\r
	136	@param CpuIndex The index of the processor.\r
	137	@param ErrorCode The Error code of exception.\r
	138	@param IsValidPFAddress The flag indicates if SMM profile data need be added.\r
	139	\r
	140	**/\r
	141	VOID\r
	142	RestorePageTableAbove4G (\r
	143	UINT64 *PageTable,\r
	144	UINT64 PFAddress,\r
	145	UINTN CpuIndex,\r
	146	UINTN ErrorCode,\r
	147	BOOLEAN *IsValidPFAddress\r
	148	)\r
	149	{\r
	150	UINTN PTIndex;\r
	151	UINT64 Address;\r
	152	BOOLEAN Nx;\r
	153	BOOLEAN Existed;\r
	154	UINTN Index;\r
	155	UINTN PFIndex;\r
	156	\r
	157	ASSERT ((PageTable != NULL) && (IsValidPFAddress != NULL));\r
	158	\r
	159	//\r
	160	// If page fault address is 4GB above.\r
	161	//\r
	162	\r
	163	//\r
	164	// Check if page fault address has existed in page table.\r
	165	// If it exists in page table but page fault is generated,\r
	166	// there are 2 possible reasons: 1. present flag is set to 0; 2. instruction fetch in protected memory range.\r
	167	//\r
	168	Existed = FALSE;\r
	169	PageTable = (UINT64*)(AsmReadCr3 () & PHYSICAL_ADDRESS_MASK);\r
	170	PTIndex = BitFieldRead64 (PFAddress, 39, 47);\r
	171	if ((PageTable[PTIndex] & IA32_PG_P) != 0) {\r
	172	// PML4E\r
	173	PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
	174	PTIndex = BitFieldRead64 (PFAddress, 30, 38);\r
	175	if ((PageTable[PTIndex] & IA32_PG_P) != 0) {\r
	176	// PDPTE\r
	177	PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
	178	PTIndex = BitFieldRead64 (PFAddress, 21, 29);\r
	179	// PD\r
	180	if ((PageTable[PTIndex] & IA32_PG_PS) != 0) {\r
	181	//\r
	182	// 2MB page\r
	183	//\r
	184	Address = (UINT64)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
	185	if ((Address & ~((1ull << 21) - 1)) == ((PFAddress & PHYSICAL_ADDRESS_MASK & ~((1ull << 21) - 1)))) {\r
	186	Existed = TRUE;\r
	187	}\r
	188	} else {\r
	189	//\r
	190	// 4KB page\r
	191	//\r
	192	PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask& PHYSICAL_ADDRESS_MASK);\r
	193	if (PageTable != 0) {\r
	194	//\r
	195	// When there is a valid entry to map to 4KB page, need not create a new entry to map 2MB.\r
	196	//\r
	197	PTIndex = BitFieldRead64 (PFAddress, 12, 20);\r
	198	Address = (UINT64)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
	199	if ((Address & ~((1ull << 12) - 1)) == (PFAddress & PHYSICAL_ADDRESS_MASK & ~((1ull << 12) - 1))) {\r
	200	Existed = TRUE;\r
	201	}\r
	202	}\r
	203	}\r
	204	}\r
	205	}\r
	206	\r
	207	//\r
	208	// If page entry does not existed in page table at all, create a new entry.\r
	209	//\r
	210	if (!Existed) {\r
	211	\r
	212	if (IsAddressValid (PFAddress, &Nx)) {\r
	213	//\r
	214	// If page fault address above 4GB is in protected range but it causes a page fault exception,\r
	215	// Will create a page entry for this page fault address, make page table entry as present/rw and execution-disable.\r
	216	// this access is not saved into SMM profile data.\r
	217	//\r
	218	*IsValidPFAddress = TRUE;\r
	219	}\r
	220	\r
	221	//\r
	222	// Create one entry in page table for page fault address.\r
	223	//\r
	224	SmiDefaultPFHandler ();\r
	225	//\r
	226	// Find the page table entry created just now.\r
	227	//\r
	228	PageTable = (UINT64*)(AsmReadCr3 () & PHYSICAL_ADDRESS_MASK);\r
	229	PFAddress = AsmReadCr2 ();\r
	230	// PML4E\r
	231	PTIndex = BitFieldRead64 (PFAddress, 39, 47);\r
	232	PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
	233	// PDPTE\r
	234	PTIndex = BitFieldRead64 (PFAddress, 30, 38);\r
	235	PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
	236	// PD\r
	237	PTIndex = BitFieldRead64 (PFAddress, 21, 29);\r
	238	Address = PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK;\r
	239	//\r
	240	// Check if 2MB-page entry need be changed to 4KB-page entry.\r
	241	//\r
	242	if (IsAddressSplit (Address)) {\r
	243	AcquirePage (&PageTable[PTIndex]);\r
	244	\r
	245	// PTE\r
	246	PageTable = (UINT64*)(UINTN)(PageTable[PTIndex] & ~mAddressEncMask & PHYSICAL_ADDRESS_MASK);\r
	247	for (Index = 0; Index < 512; Index++) {\r
	248	PageTable[Index] = Address \| mAddressEncMask \| PAGE_ATTRIBUTE_BITS;\r
	249	if (!IsAddressValid (Address, &Nx)) {\r
	250	PageTable[Index] = PageTable[Index] & (INTN)(INT32)(~PAGE_ATTRIBUTE_BITS);\r
	251	}\r
	252	if (Nx && mXdSupported) {\r
	253	PageTable[Index] = PageTable[Index] \| IA32_PG_NX;\r
	254	}\r
	255	if (Address == (PFAddress & PHYSICAL_ADDRESS_MASK & ~((1ull << 12) - 1))) {\r
	256	PTIndex = Index;\r
	257	}\r
	258	Address += SIZE_4KB;\r
	259	} // end for PT\r
	260	} else {\r
	261	//\r
	262	// Update 2MB page entry.\r
	263	//\r
	264	if (!IsAddressValid (Address, &Nx)) {\r
	265	//\r
	266	// Patch to remove present flag and rw flag.\r
	267	//\r
	268	PageTable[PTIndex] = PageTable[PTIndex] & (INTN)(INT32)(~PAGE_ATTRIBUTE_BITS);\r
	269	}\r
	270	//\r
	271	// Set XD bit to 1\r
	272	//\r
	273	if (Nx && mXdSupported) {\r
	274	PageTable[PTIndex] = PageTable[PTIndex] \| IA32_PG_NX;\r
	275	}\r
	276	}\r
	277	}\r
	278	\r
	279	//\r
	280	// Record old entries with non-present status\r
	281	// Old entries include the memory which instruction is at and the memory which instruction access.\r
	282	//\r
	283	//\r
	284	ASSERT (mPFEntryCount[CpuIndex] < MAX_PF_ENTRY_COUNT);\r
	285	if (mPFEntryCount[CpuIndex] < MAX_PF_ENTRY_COUNT) {\r
	286	PFIndex = mPFEntryCount[CpuIndex];\r
	287	mLastPFEntryValue[CpuIndex][PFIndex] = PageTable[PTIndex];\r
	288	mLastPFEntryPointer[CpuIndex][PFIndex] = &PageTable[PTIndex];\r
	289	mPFEntryCount[CpuIndex]++;\r
	290	}\r
	291	\r
	292	//\r
	293	// Add present flag or clear XD flag to make page fault handler succeed.\r
	294	//\r
	295	PageTable[PTIndex] \|= (UINT64)(PAGE_ATTRIBUTE_BITS);\r
	296	if ((ErrorCode & IA32_PF_EC_ID) != 0) {\r
	297	//\r
	298	// If page fault is caused by instruction fetch, clear XD bit in the entry.\r
	299	//\r
	300	PageTable[PTIndex] &= ~IA32_PG_NX;\r
	301	}\r
	302	\r
	303	return;\r
	304	}\r
	305	\r
	306	/**\r
	307	Clear TF in FLAGS.\r
	308	\r
	309	@param SystemContext A pointer to the processor context when\r
	310	the interrupt occurred on the processor.\r
	311	\r
	312	**/\r
	313	VOID\r
	314	ClearTrapFlag (\r
	315	IN OUT EFI_SYSTEM_CONTEXT SystemContext\r
	316	)\r
	317	{\r
	318	SystemContext.SystemContextX64->Rflags &= (UINTN) ~BIT8;\r
	319	}\r