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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"
/**
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 HoStart 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;
}
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);
}
/**
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 = AllocatePages (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) {
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 = AllocatePages (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 ((IsNullDetectionEnabled () && PhysicalAddress2M == 0)
|| (PcdGetBool (PcdSetNxForStack)
&& (PhysicalAddress2M < StackBase + StackSize)
&& ((PhysicalAddress2M + SIZE_2MB) > StackBase))) {
//
// 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;
}
}
}
/**
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) AllocatePages (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 ((IsNullDetectionEnabled () && PageAddress == 0)
|| (PcdGetBool (PcdSetNxForStack)
&& (PageAddress < StackBase + StackSize)
&& ((PageAddress + SIZE_1GB) > StackBase))) {
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 ((IsNullDetectionEnabled () && PageAddress == 0)
|| (PcdGetBool (PcdSetNxForStack)
&& (PageAddress < StackBase + StackSize)
&& ((PageAddress + SIZE_2MB) > StackBase))) {
//
// 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)
);
}
if (PcdGetBool (PcdSetNxForStack)) {
EnableExecuteDisableBit ();
}
return (UINTN)PageMap;
}
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