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audk/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c

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/** @file
x64 Virtual Memory Management Services in the form of an IA-32 driver.
Used to establish a 1:1 Virtual to Physical Mapping that is required to
enter Long Mode (x64 64-bit mode).
While we make a 1:1 mapping (identity mapping) for all physical pages
we still need to use the MTRR's to ensure that the cachability attributes
for all memory regions is correct.
The basic idea is to use 2MB page table entries where ever possible. If
more granularity of cachability is required then 4K page tables are used.
References:
1) IA-32 Intel(R) Architecture Software Developer's Manual Volume 1:Basic Architecture, Intel
2) IA-32 Intel(R) Architecture Software Developer's Manual Volume 2:Instruction Set Reference, Intel
3) IA-32 Intel(R) Architecture Software Developer's Manual Volume 3:System Programmer's Guide, Intel
Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
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 "DxeIpl.h"
#include "VirtualMemory.h"
//
// Global variable to keep track current available memory used as page table.
//
PAGE_TABLE_POOL *mPageTablePool = NULL;
/**
Clear legacy memory located at the first 4K-page, if available.
This function traverses the whole HOB list to check if memory from 0 to 4095
exists and has not been allocated, and then clear it if so.
@param HobStart The start of HobList passed to DxeCore.
**/
VOID
ClearFirst4KPage (
IN VOID *HobStart
)
{
EFI_PEI_HOB_POINTERS RscHob;
EFI_PEI_HOB_POINTERS MemHob;
BOOLEAN DoClear;
RscHob.Raw = HobStart;
MemHob.Raw = HobStart;
DoClear = FALSE;
//
// Check if page 0 exists and free
//
while ((RscHob.Raw = GetNextHob (EFI_HOB_TYPE_RESOURCE_DESCRIPTOR,
RscHob.Raw)) != NULL) {
if (RscHob.ResourceDescriptor->ResourceType == EFI_RESOURCE_SYSTEM_MEMORY &&
RscHob.ResourceDescriptor->PhysicalStart == 0) {
DoClear = TRUE;
//
// Make sure memory at 0-4095 has not been allocated.
//
while ((MemHob.Raw = GetNextHob (EFI_HOB_TYPE_MEMORY_ALLOCATION,
MemHob.Raw)) != NULL) {
if (MemHob.MemoryAllocation->AllocDescriptor.MemoryBaseAddress
< EFI_PAGE_SIZE) {
DoClear = FALSE;
break;
}
MemHob.Raw = GET_NEXT_HOB (MemHob);
}
break;
}
RscHob.Raw = GET_NEXT_HOB (RscHob);
}
if (DoClear) {
DEBUG ((DEBUG_INFO, "Clearing first 4K-page!\r\n"));
SetMem (NULL, EFI_PAGE_SIZE, 0);
}
return;
}
/**
Return configure status of NULL pointer detection feature.
@return TRUE NULL pointer detection feature is enabled
@return FALSE NULL pointer detection feature is disabled
**/
BOOLEAN
IsNullDetectionEnabled (
VOID
)
{
return ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) != 0);
}
/**
Enable Execute Disable Bit.
**/
VOID
EnableExecuteDisableBit (
VOID
)
{
UINT64 MsrRegisters;
MsrRegisters = AsmReadMsr64 (0xC0000080);
MsrRegisters |= BIT11;
AsmWriteMsr64 (0xC0000080, MsrRegisters);
}
/**
The function will check if page table entry should be splitted to smaller
granularity.
@param Address Physical memory address.
@param Size Size of the given physical memory.
@param StackBase Base address of stack.
@param StackSize Size of stack.
@retval TRUE Page table should be split.
@retval FALSE Page table should not be split.
**/
BOOLEAN
ToSplitPageTable (
IN EFI_PHYSICAL_ADDRESS Address,
IN UINTN Size,
IN EFI_PHYSICAL_ADDRESS StackBase,
IN UINTN StackSize
)
{
if (IsNullDetectionEnabled () && Address == 0) {
return TRUE;
}
if (PcdGetBool (PcdCpuStackGuard)) {
if (StackBase >= Address && StackBase < (Address + Size)) {
return TRUE;
}
}
if (PcdGetBool (PcdSetNxForStack)) {
if ((Address < StackBase + StackSize) && ((Address + Size) > StackBase)) {
return TRUE;
}
}
return FALSE;
}
/**
Initialize a buffer pool for page table use only.
To reduce the potential split operation on page table, the pages reserved for
page table should be allocated in the times of PAGE_TABLE_POOL_UNIT_PAGES and
at the boundary of PAGE_TABLE_POOL_ALIGNMENT. So the page pool is always
initialized with number of pages greater than or equal to the given PoolPages.
Once the pages in the pool are used up, this method should be called again to
reserve at least another PAGE_TABLE_POOL_UNIT_PAGES. But usually this won't
happen in practice.
@param PoolPages The least page number of the pool to be created.
@retval TRUE The pool is initialized successfully.
@retval FALSE The memory is out of resource.
**/
BOOLEAN
InitializePageTablePool (
IN UINTN PoolPages
)
{
VOID *Buffer;
//
// Always reserve at least PAGE_TABLE_POOL_UNIT_PAGES, including one page for
// header.
//
PoolPages += 1; // Add one page for header.
PoolPages = ((PoolPages - 1) / PAGE_TABLE_POOL_UNIT_PAGES + 1) *
PAGE_TABLE_POOL_UNIT_PAGES;
Buffer = AllocateAlignedPages (PoolPages, PAGE_TABLE_POOL_ALIGNMENT);
if (Buffer == NULL) {
DEBUG ((DEBUG_ERROR, "ERROR: Out of aligned pages\r\n"));
return FALSE;
}
//
// Link all pools into a list for easier track later.
//
if (mPageTablePool == NULL) {
mPageTablePool = Buffer;
mPageTablePool->NextPool = mPageTablePool;
} else {
((PAGE_TABLE_POOL *)Buffer)->NextPool = mPageTablePool->NextPool;
mPageTablePool->NextPool = Buffer;
mPageTablePool = Buffer;
}
//
// Reserve one page for pool header.
//
mPageTablePool->FreePages = PoolPages - 1;
mPageTablePool->Offset = EFI_PAGES_TO_SIZE (1);
return TRUE;
}
/**
This API provides a way to allocate memory for page table.
This API can be called more than once to allocate memory for page tables.
Allocates the number of 4KB pages and returns a pointer to the allocated
buffer. The buffer returned is aligned on a 4KB boundary.
If Pages is 0, then NULL is returned.
If there is not enough memory remaining to satisfy the request, then NULL is
returned.
@param Pages The number of 4 KB pages to allocate.
@return A pointer to the allocated buffer or NULL if allocation fails.
**/
VOID *
AllocatePageTableMemory (
IN UINTN Pages
)
{
VOID *Buffer;
if (Pages == 0) {
return NULL;
}
//
// Renew the pool if necessary.
//
if (mPageTablePool == NULL ||
Pages > mPageTablePool->FreePages) {
if (!InitializePageTablePool (Pages)) {
return NULL;
}
}
Buffer = (UINT8 *)mPageTablePool + mPageTablePool->Offset;
mPageTablePool->Offset += EFI_PAGES_TO_SIZE (Pages);
mPageTablePool->FreePages -= Pages;
return Buffer;
}
/**
Split 2M page to 4K.
@param[in] PhysicalAddress Start physical address the 2M page covered.
@param[in, out] PageEntry2M Pointer to 2M page entry.
@param[in] StackBase Stack base address.
@param[in] StackSize Stack size.
**/
VOID
Split2MPageTo4K (
IN EFI_PHYSICAL_ADDRESS PhysicalAddress,
IN OUT UINT64 *PageEntry2M,
IN EFI_PHYSICAL_ADDRESS StackBase,
IN UINTN StackSize
)
{
EFI_PHYSICAL_ADDRESS PhysicalAddress4K;
UINTN IndexOfPageTableEntries;
PAGE_TABLE_4K_ENTRY *PageTableEntry;
UINT64 AddressEncMask;
//
// Make sure AddressEncMask is contained to smallest supported address field
//
AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) & PAGING_1G_ADDRESS_MASK_64;
PageTableEntry = AllocatePageTableMemory (1);
ASSERT (PageTableEntry != NULL);
//
// Fill in 2M page entry.
//
*PageEntry2M = (UINT64) (UINTN) PageTableEntry | AddressEncMask | IA32_PG_P | IA32_PG_RW;
PhysicalAddress4K = PhysicalAddress;
for (IndexOfPageTableEntries = 0; IndexOfPageTableEntries < 512; IndexOfPageTableEntries++, PageTableEntry++, PhysicalAddress4K += SIZE_4KB) {
//
// Fill in the Page Table entries
//
PageTableEntry->Uint64 = (UINT64) PhysicalAddress4K | AddressEncMask;
PageTableEntry->Bits.ReadWrite = 1;
if ((IsNullDetectionEnabled () && PhysicalAddress4K == 0) ||
(PcdGetBool (PcdCpuStackGuard) && PhysicalAddress4K == StackBase)) {
PageTableEntry->Bits.Present = 0;
} else {
PageTableEntry->Bits.Present = 1;
}
if (PcdGetBool (PcdSetNxForStack)
&& (PhysicalAddress4K >= StackBase)
&& (PhysicalAddress4K < StackBase + StackSize)) {
//
// Set Nx bit for stack.
//
PageTableEntry->Bits.Nx = 1;
}
}
}
/**
Split 1G page to 2M.
@param[in] PhysicalAddress Start physical address the 1G page covered.
@param[in, out] PageEntry1G Pointer to 1G page entry.
@param[in] StackBase Stack base address.
@param[in] StackSize Stack size.
**/
VOID
Split1GPageTo2M (
IN EFI_PHYSICAL_ADDRESS PhysicalAddress,
IN OUT UINT64 *PageEntry1G,
IN EFI_PHYSICAL_ADDRESS StackBase,
IN UINTN StackSize
)
{
EFI_PHYSICAL_ADDRESS PhysicalAddress2M;
UINTN IndexOfPageDirectoryEntries;
PAGE_TABLE_ENTRY *PageDirectoryEntry;
UINT64 AddressEncMask;
//
// Make sure AddressEncMask is contained to smallest supported address field
//
AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) & PAGING_1G_ADDRESS_MASK_64;
PageDirectoryEntry = AllocatePageTableMemory (1);
ASSERT (PageDirectoryEntry != NULL);
//
// Fill in 1G page entry.
//
*PageEntry1G = (UINT64) (UINTN) PageDirectoryEntry | AddressEncMask | IA32_PG_P | IA32_PG_RW;
PhysicalAddress2M = PhysicalAddress;
for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PhysicalAddress2M += SIZE_2MB) {
if (ToSplitPageTable (PhysicalAddress2M, SIZE_2MB, StackBase, StackSize)) {
//
// Need to split this 2M page that covers NULL or stack range.
//
Split2MPageTo4K (PhysicalAddress2M, (UINT64 *) PageDirectoryEntry, StackBase, StackSize);
} else {
//
// Fill in the Page Directory entries
//
PageDirectoryEntry->Uint64 = (UINT64) PhysicalAddress2M | AddressEncMask;
PageDirectoryEntry->Bits.ReadWrite = 1;
PageDirectoryEntry->Bits.Present = 1;
PageDirectoryEntry->Bits.MustBe1 = 1;
}
}
}
/**
Set one page of page table pool memory to be read-only.
@param[in] PageTableBase Base address of page table (CR3).
@param[in] Address Start address of a page to be set as read-only.
@param[in] Level4Paging Level 4 paging flag.
**/
VOID
SetPageTablePoolReadOnly (
IN UINTN PageTableBase,
IN EFI_PHYSICAL_ADDRESS Address,
IN BOOLEAN Level4Paging
)
{
UINTN Index;
UINTN EntryIndex;
UINT64 AddressEncMask;
EFI_PHYSICAL_ADDRESS PhysicalAddress;
UINT64 *PageTable;
UINT64 *NewPageTable;
UINT64 PageAttr;
UINT64 LevelSize[5];
UINT64 LevelMask[5];
UINTN LevelShift[5];
UINTN Level;
UINT64 PoolUnitSize;
ASSERT (PageTableBase != 0);
//
// Since the page table is always from page table pool, which is always
// located at the boundary of PcdPageTablePoolAlignment, we just need to
// set the whole pool unit to be read-only.
//
Address = Address & PAGE_TABLE_POOL_ALIGN_MASK;
LevelShift[1] = PAGING_L1_ADDRESS_SHIFT;
LevelShift[2] = PAGING_L2_ADDRESS_SHIFT;
LevelShift[3] = PAGING_L3_ADDRESS_SHIFT;
LevelShift[4] = PAGING_L4_ADDRESS_SHIFT;
LevelMask[1] = PAGING_4K_ADDRESS_MASK_64;
LevelMask[2] = PAGING_2M_ADDRESS_MASK_64;
LevelMask[3] = PAGING_1G_ADDRESS_MASK_64;
LevelMask[4] = PAGING_1G_ADDRESS_MASK_64;
LevelSize[1] = SIZE_4KB;
LevelSize[2] = SIZE_2MB;
LevelSize[3] = SIZE_1GB;
LevelSize[4] = SIZE_512GB;
AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) &
PAGING_1G_ADDRESS_MASK_64;
PageTable = (UINT64 *)(UINTN)PageTableBase;
PoolUnitSize = PAGE_TABLE_POOL_UNIT_SIZE;
for (Level = (Level4Paging) ? 4 : 3; Level > 0; --Level) {
Index = ((UINTN)RShiftU64 (Address, LevelShift[Level]));
Index &= PAGING_PAE_INDEX_MASK;
PageAttr = PageTable[Index];
if ((PageAttr & IA32_PG_PS) == 0) {
//
// Go to next level of table.
//
PageTable = (UINT64 *)(UINTN)(PageAttr & ~AddressEncMask &
PAGING_4K_ADDRESS_MASK_64);
continue;
}
if (PoolUnitSize >= LevelSize[Level]) {
//
// Clear R/W bit if current page granularity is not larger than pool unit
// size.
//
if ((PageAttr & IA32_PG_RW) != 0) {
while (PoolUnitSize > 0) {
//
// PAGE_TABLE_POOL_UNIT_SIZE and PAGE_TABLE_POOL_ALIGNMENT are fit in
// one page (2MB). Then we don't need to update attributes for pages
// crossing page directory. ASSERT below is for that purpose.
//
ASSERT (Index < EFI_PAGE_SIZE/sizeof (UINT64));
PageTable[Index] &= ~(UINT64)IA32_PG_RW;
PoolUnitSize -= LevelSize[Level];
++Index;
}
}
break;
} else {
//
// The smaller granularity of page must be needed.
//
ASSERT (Level > 1);
NewPageTable = AllocatePageTableMemory (1);
ASSERT (NewPageTable != NULL);
PhysicalAddress = PageAttr & LevelMask[Level];
for (EntryIndex = 0;
EntryIndex < EFI_PAGE_SIZE/sizeof (UINT64);
++EntryIndex) {
NewPageTable[EntryIndex] = PhysicalAddress | AddressEncMask |
IA32_PG_P | IA32_PG_RW;
if (Level > 2) {
NewPageTable[EntryIndex] |= IA32_PG_PS;
}
PhysicalAddress += LevelSize[Level - 1];
}
PageTable[Index] = (UINT64)(UINTN)NewPageTable | AddressEncMask |
IA32_PG_P | IA32_PG_RW;
PageTable = NewPageTable;
}
}
}
/**
Prevent the memory pages used for page table from been overwritten.
@param[in] PageTableBase Base address of page table (CR3).
@param[in] Level4Paging Level 4 paging flag.
**/
VOID
EnablePageTableProtection (
IN UINTN PageTableBase,
IN BOOLEAN Level4Paging
)
{
PAGE_TABLE_POOL *HeadPool;
PAGE_TABLE_POOL *Pool;
UINT64 PoolSize;
EFI_PHYSICAL_ADDRESS Address;
if (mPageTablePool == NULL) {
return;
}
//
// Disable write protection, because we need to mark page table to be write
// protected.
//
AsmWriteCr0 (AsmReadCr0() & ~CR0_WP);
//
// SetPageTablePoolReadOnly might update mPageTablePool. It's safer to
// remember original one in advance.
//
HeadPool = mPageTablePool;
Pool = HeadPool;
do {
Address = (EFI_PHYSICAL_ADDRESS)(UINTN)Pool;
PoolSize = Pool->Offset + EFI_PAGES_TO_SIZE (Pool->FreePages);
//
// The size of one pool must be multiple of PAGE_TABLE_POOL_UNIT_SIZE, which
// is one of page size of the processor (2MB by default). Let's apply the
// protection to them one by one.
//
while (PoolSize > 0) {
SetPageTablePoolReadOnly(PageTableBase, Address, Level4Paging);
Address += PAGE_TABLE_POOL_UNIT_SIZE;
PoolSize -= PAGE_TABLE_POOL_UNIT_SIZE;
}
Pool = Pool->NextPool;
} while (Pool != HeadPool);
//
// Enable write protection, after page table attribute updated.
//
AsmWriteCr0 (AsmReadCr0() | CR0_WP);
}
/**
Allocates and fills in the Page Directory and Page Table Entries to
establish a 1:1 Virtual to Physical mapping.
@param[in] StackBase Stack base address.
@param[in] StackSize Stack size.
@return The address of 4 level page map.
**/
UINTN
CreateIdentityMappingPageTables (
IN EFI_PHYSICAL_ADDRESS StackBase,
IN UINTN StackSize
)
{
UINT32 RegEax;
UINT32 RegEdx;
UINT8 PhysicalAddressBits;
EFI_PHYSICAL_ADDRESS PageAddress;
UINTN IndexOfPml4Entries;
UINTN IndexOfPdpEntries;
UINTN IndexOfPageDirectoryEntries;
UINT32 NumberOfPml4EntriesNeeded;
UINT32 NumberOfPdpEntriesNeeded;
PAGE_MAP_AND_DIRECTORY_POINTER *PageMapLevel4Entry;
PAGE_MAP_AND_DIRECTORY_POINTER *PageMap;
PAGE_MAP_AND_DIRECTORY_POINTER *PageDirectoryPointerEntry;
PAGE_TABLE_ENTRY *PageDirectoryEntry;
UINTN TotalPagesNum;
UINTN BigPageAddress;
VOID *Hob;
BOOLEAN Page1GSupport;
PAGE_TABLE_1G_ENTRY *PageDirectory1GEntry;
UINT64 AddressEncMask;
//
// Make sure AddressEncMask is contained to smallest supported address field
//
AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) & PAGING_1G_ADDRESS_MASK_64;
Page1GSupport = FALSE;
if (PcdGetBool(PcdUse1GPageTable)) {
AsmCpuid (0x80000000, &RegEax, NULL, NULL, NULL);
if (RegEax >= 0x80000001) {
AsmCpuid (0x80000001, NULL, NULL, NULL, &RegEdx);
if ((RegEdx & BIT26) != 0) {
Page1GSupport = TRUE;
}
}
}
//
// Get physical address bits supported.
//
Hob = GetFirstHob (EFI_HOB_TYPE_CPU);
if (Hob != NULL) {
PhysicalAddressBits = ((EFI_HOB_CPU *) Hob)->SizeOfMemorySpace;
} else {
AsmCpuid (0x80000000, &RegEax, NULL, NULL, NULL);
if (RegEax >= 0x80000008) {
AsmCpuid (0x80000008, &RegEax, NULL, NULL, NULL);
PhysicalAddressBits = (UINT8) RegEax;
} else {
PhysicalAddressBits = 36;
}
}
//
// IA-32e paging translates 48-bit linear addresses to 52-bit physical addresses.
//
ASSERT (PhysicalAddressBits <= 52);
if (PhysicalAddressBits > 48) {
PhysicalAddressBits = 48;
}
//
// Calculate the table entries needed.
//
if (PhysicalAddressBits <= 39 ) {
NumberOfPml4EntriesNeeded = 1;
NumberOfPdpEntriesNeeded = (UINT32)LShiftU64 (1, (PhysicalAddressBits - 30));
} else {
NumberOfPml4EntriesNeeded = (UINT32)LShiftU64 (1, (PhysicalAddressBits - 39));
NumberOfPdpEntriesNeeded = 512;
}
//
// Pre-allocate big pages to avoid later allocations.
//
if (!Page1GSupport) {
TotalPagesNum = (NumberOfPdpEntriesNeeded + 1) * NumberOfPml4EntriesNeeded + 1;
} else {
TotalPagesNum = NumberOfPml4EntriesNeeded + 1;
}
BigPageAddress = (UINTN) AllocatePageTableMemory (TotalPagesNum);
ASSERT (BigPageAddress != 0);
//
// By architecture only one PageMapLevel4 exists - so lets allocate storage for it.
//
PageMap = (VOID *) BigPageAddress;
BigPageAddress += SIZE_4KB;
PageMapLevel4Entry = PageMap;
PageAddress = 0;
for (IndexOfPml4Entries = 0; IndexOfPml4Entries < NumberOfPml4EntriesNeeded; IndexOfPml4Entries++, PageMapLevel4Entry++) {
//
// Each PML4 entry points to a page of Page Directory Pointer entires.
// So lets allocate space for them and fill them in in the IndexOfPdpEntries loop.
//
PageDirectoryPointerEntry = (VOID *) BigPageAddress;
BigPageAddress += SIZE_4KB;
//
// Make a PML4 Entry
//
PageMapLevel4Entry->Uint64 = (UINT64)(UINTN)PageDirectoryPointerEntry | AddressEncMask;
PageMapLevel4Entry->Bits.ReadWrite = 1;
PageMapLevel4Entry->Bits.Present = 1;
if (Page1GSupport) {
PageDirectory1GEntry = (VOID *) PageDirectoryPointerEntry;
for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectory1GEntry++, PageAddress += SIZE_1GB) {
if (ToSplitPageTable (PageAddress, SIZE_1GB, StackBase, StackSize)) {
Split1GPageTo2M (PageAddress, (UINT64 *) PageDirectory1GEntry, StackBase, StackSize);
} else {
//
// Fill in the Page Directory entries
//
PageDirectory1GEntry->Uint64 = (UINT64)PageAddress | AddressEncMask;
PageDirectory1GEntry->Bits.ReadWrite = 1;
PageDirectory1GEntry->Bits.Present = 1;
PageDirectory1GEntry->Bits.MustBe1 = 1;
}
}
} else {
for (IndexOfPdpEntries = 0; IndexOfPdpEntries < NumberOfPdpEntriesNeeded; IndexOfPdpEntries++, PageDirectoryPointerEntry++) {
//
// Each Directory Pointer entries points to a page of Page Directory entires.
// So allocate space for them and fill them in in the IndexOfPageDirectoryEntries loop.
//
PageDirectoryEntry = (VOID *) BigPageAddress;
BigPageAddress += SIZE_4KB;
//
// Fill in a Page Directory Pointer Entries
//
PageDirectoryPointerEntry->Uint64 = (UINT64)(UINTN)PageDirectoryEntry | AddressEncMask;
PageDirectoryPointerEntry->Bits.ReadWrite = 1;
PageDirectoryPointerEntry->Bits.Present = 1;
for (IndexOfPageDirectoryEntries = 0; IndexOfPageDirectoryEntries < 512; IndexOfPageDirectoryEntries++, PageDirectoryEntry++, PageAddress += SIZE_2MB) {
if (ToSplitPageTable (PageAddress, SIZE_2MB, StackBase, StackSize)) {
//
// Need to split this 2M page that covers NULL or stack range.
//
Split2MPageTo4K (PageAddress, (UINT64 *) PageDirectoryEntry, StackBase, StackSize);
} else {
//
// Fill in the Page Directory entries
//
PageDirectoryEntry->Uint64 = (UINT64)PageAddress | AddressEncMask;
PageDirectoryEntry->Bits.ReadWrite = 1;
PageDirectoryEntry->Bits.Present = 1;
PageDirectoryEntry->Bits.MustBe1 = 1;
}
}
}
for (; IndexOfPdpEntries < 512; IndexOfPdpEntries++, PageDirectoryPointerEntry++) {
ZeroMem (
PageDirectoryPointerEntry,
sizeof(PAGE_MAP_AND_DIRECTORY_POINTER)
);
}
}
}
//
// For the PML4 entries we are not using fill in a null entry.
//
for (; IndexOfPml4Entries < 512; IndexOfPml4Entries++, PageMapLevel4Entry++) {
ZeroMem (
PageMapLevel4Entry,
sizeof (PAGE_MAP_AND_DIRECTORY_POINTER)
);
}
//
// Protect the page table by marking the memory used for page table to be
// read-only.
//
EnablePageTableProtection ((UINTN)PageMap, TRUE);
if (PcdGetBool (PcdSetNxForStack)) {
EnableExecuteDisableBit ();
}
return (UINTN)PageMap;
}
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