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audk/UefiCpuPkg/CpuDxe/CpuPageTable.c

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/** @file
Page table management support.
Copyright (c) 2017, 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 <Base.h>
#include <Uefi.h>
#include <Library/PeCoffGetEntryPointLib.h>
#include <Library/SerialPortLib.h>
#include <Library/SynchronizationLib.h>
#include <Library/PrintLib.h>
#include <Protocol/SmmBase2.h>
#include <Register/Cpuid.h>
#include <Register/Msr.h>
#include "CpuDxe.h"
#include "CpuPageTable.h"
///
/// Paging registers
///
#define CR0_WP BIT16
#define CR0_PG BIT31
#define CR4_PSE BIT4
#define CR4_PAE BIT5
///
/// Page Table Entry
///
#define IA32_PG_P BIT0
#define IA32_PG_RW BIT1
#define IA32_PG_U BIT2
#define IA32_PG_WT BIT3
#define IA32_PG_CD BIT4
#define IA32_PG_A BIT5
#define IA32_PG_D BIT6
#define IA32_PG_PS BIT7
#define IA32_PG_PAT_2M BIT12
#define IA32_PG_PAT_4K IA32_PG_PS
#define IA32_PG_PMNT BIT62
#define IA32_PG_NX BIT63
#define PAGE_ATTRIBUTE_BITS (IA32_PG_D | IA32_PG_A | IA32_PG_U | IA32_PG_RW | IA32_PG_P)
//
// Bits 1, 2, 5, 6 are reserved in the IA32 PAE PDPTE
// X64 PAE PDPTE does not have such restriction
//
#define IA32_PAE_PDPTE_ATTRIBUTE_BITS (IA32_PG_P)
#define PAGE_PROGATE_BITS (IA32_PG_NX | PAGE_ATTRIBUTE_BITS)
#define PAGING_4K_MASK 0xFFF
#define PAGING_2M_MASK 0x1FFFFF
#define PAGING_1G_MASK 0x3FFFFFFF
#define PAGING_PAE_INDEX_MASK 0x1FF
#define PAGING_4K_ADDRESS_MASK_64 0x000FFFFFFFFFF000ull
#define PAGING_2M_ADDRESS_MASK_64 0x000FFFFFFFE00000ull
#define PAGING_1G_ADDRESS_MASK_64 0x000FFFFFC0000000ull
#define MAX_PF_ENTRY_COUNT 10
#define MAX_DEBUG_MESSAGE_LENGTH 0x100
#define IA32_PF_EC_ID BIT4
typedef enum {
PageNone,
Page4K,
Page2M,
Page1G,
} PAGE_ATTRIBUTE;
typedef struct {
PAGE_ATTRIBUTE Attribute;
UINT64 Length;
UINT64 AddressMask;
} PAGE_ATTRIBUTE_TABLE;
typedef enum {
PageActionAssign,
PageActionSet,
PageActionClear,
} PAGE_ACTION;
PAGE_ATTRIBUTE_TABLE mPageAttributeTable[] = {
{Page4K, SIZE_4KB, PAGING_4K_ADDRESS_MASK_64},
{Page2M, SIZE_2MB, PAGING_2M_ADDRESS_MASK_64},
{Page1G, SIZE_1GB, PAGING_1G_ADDRESS_MASK_64},
};
PAGE_TABLE_POOL *mPageTablePool = NULL;
PAGE_TABLE_LIB_PAGING_CONTEXT mPagingContext;
EFI_SMM_BASE2_PROTOCOL *mSmmBase2 = NULL;
//
// Record the page fault exception count for one instruction execution.
//
UINTN *mPFEntryCount;
UINT64 *(*mLastPFEntryPointer)[MAX_PF_ENTRY_COUNT];
/**
Check if current execution environment is in SMM mode or not, via
EFI_SMM_BASE2_PROTOCOL.
This is necessary because of the fact that MdePkg\Library\SmmMemoryAllocationLib
supports to free memory outside SMRAM. The library will call gBS->FreePool() or
gBS->FreePages() and then SetMemorySpaceAttributes interface in turn to change
memory paging attributes during free operation, if some memory related features
are enabled (like Heap Guard).
This means that SetMemorySpaceAttributes() has chance to run in SMM mode. This
will cause incorrect result because SMM mode always loads its own page tables,
which are usually different from DXE. This function can be used to detect such
situation and help to avoid further misoperations.
@retval TRUE In SMM mode.
@retval FALSE Not in SMM mode.
**/
BOOLEAN
IsInSmm (
VOID
)
{
BOOLEAN InSmm;
InSmm = FALSE;
if (mSmmBase2 == NULL) {
gBS->LocateProtocol (&gEfiSmmBase2ProtocolGuid, NULL, (VOID **)&mSmmBase2);
}
if (mSmmBase2 != NULL) {
mSmmBase2->InSmm (mSmmBase2, &InSmm);
}
//
// mSmmBase2->InSmm() can only detect if the caller is running in SMRAM
// or from SMM driver. It cannot tell if the caller is running in SMM mode.
// Check page table base address to guarantee that because SMM mode willl
// load its own page table.
//
return (InSmm &&
mPagingContext.ContextData.X64.PageTableBase != (UINT64)AsmReadCr3());
}
/**
Return current paging context.
@param[in,out] PagingContext The paging context.
**/
VOID
GetCurrentPagingContext (
IN OUT PAGE_TABLE_LIB_PAGING_CONTEXT *PagingContext
)
{
UINT32 RegEax;
CPUID_EXTENDED_CPU_SIG_EDX RegEdx;
MSR_IA32_EFER_REGISTER MsrEfer;
//
// Don't retrieve current paging context from processor if in SMM mode.
//
if (!IsInSmm ()) {
ZeroMem (&mPagingContext, sizeof(mPagingContext));
if (sizeof(UINTN) == sizeof(UINT64)) {
mPagingContext.MachineType = IMAGE_FILE_MACHINE_X64;
} else {
mPagingContext.MachineType = IMAGE_FILE_MACHINE_I386;
}
if ((AsmReadCr0 () & CR0_PG) != 0) {
mPagingContext.ContextData.X64.PageTableBase = (AsmReadCr3 () & PAGING_4K_ADDRESS_MASK_64);
} else {
mPagingContext.ContextData.X64.PageTableBase = 0;
}
if ((AsmReadCr4 () & CR4_PSE) != 0) {
mPagingContext.ContextData.Ia32.Attributes |= PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PSE;
}
if ((AsmReadCr4 () & CR4_PAE) != 0) {
mPagingContext.ContextData.Ia32.Attributes |= PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAE;
}
if ((AsmReadCr0 () & CR0_WP) != 0) {
mPagingContext.ContextData.Ia32.Attributes |= PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_WP_ENABLE;
}
AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
if (RegEax >= CPUID_EXTENDED_CPU_SIG) {
AsmCpuid (CPUID_EXTENDED_CPU_SIG, NULL, NULL, NULL, &RegEdx.Uint32);
if (RegEdx.Bits.NX != 0) {
// XD supported
MsrEfer.Uint64 = AsmReadMsr64(MSR_CORE_IA32_EFER);
if (MsrEfer.Bits.NXE != 0) {
// XD activated
mPagingContext.ContextData.Ia32.Attributes |= PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_XD_ACTIVATED;
}
}
if (RegEdx.Bits.Page1GB != 0) {
mPagingContext.ContextData.Ia32.Attributes |= PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAGE_1G_SUPPORT;
}
}
}
//
// This can avoid getting SMM paging context if in SMM mode. We cannot assume
// SMM mode shares the same paging context as DXE.
//
CopyMem (PagingContext, &mPagingContext, sizeof (mPagingContext));
}
/**
Return length according to page attributes.
@param[in] PageAttributes The page attribute of the page entry.
@return The length of page entry.
**/
UINTN
PageAttributeToLength (
IN PAGE_ATTRIBUTE PageAttribute
)
{
UINTN Index;
for (Index = 0; Index < sizeof(mPageAttributeTable)/sizeof(mPageAttributeTable[0]); Index++) {
if (PageAttribute == mPageAttributeTable[Index].Attribute) {
return (UINTN)mPageAttributeTable[Index].Length;
}
}
return 0;
}
/**
Return address mask according to page attributes.
@param[in] PageAttributes The page attribute of the page entry.
@return The address mask of page entry.
**/
UINTN
PageAttributeToMask (
IN PAGE_ATTRIBUTE PageAttribute
)
{
UINTN Index;
for (Index = 0; Index < sizeof(mPageAttributeTable)/sizeof(mPageAttributeTable[0]); Index++) {
if (PageAttribute == mPageAttributeTable[Index].Attribute) {
return (UINTN)mPageAttributeTable[Index].AddressMask;
}
}
return 0;
}
/**
Return page table entry to match the address.
@param[in] PagingContext The paging context.
@param[in] Address The address to be checked.
@param[out] PageAttributes The page attribute of the page entry.
@return The page entry.
**/
VOID *
GetPageTableEntry (
IN PAGE_TABLE_LIB_PAGING_CONTEXT *PagingContext,
IN PHYSICAL_ADDRESS Address,
OUT PAGE_ATTRIBUTE *PageAttribute
)
{
UINTN Index1;
UINTN Index2;
UINTN Index3;
UINTN Index4;
UINT64 *L1PageTable;
UINT64 *L2PageTable;
UINT64 *L3PageTable;
UINT64 *L4PageTable;
UINT64 AddressEncMask;
ASSERT (PagingContext != NULL);
Index4 = ((UINTN)RShiftU64 (Address, 39)) & PAGING_PAE_INDEX_MASK;
Index3 = ((UINTN)Address >> 30) & PAGING_PAE_INDEX_MASK;
Index2 = ((UINTN)Address >> 21) & PAGING_PAE_INDEX_MASK;
Index1 = ((UINTN)Address >> 12) & PAGING_PAE_INDEX_MASK;
// Make sure AddressEncMask is contained to smallest supported address field.
//
AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) & PAGING_1G_ADDRESS_MASK_64;
if (PagingContext->MachineType == IMAGE_FILE_MACHINE_X64) {
L4PageTable = (UINT64 *)(UINTN)PagingContext->ContextData.X64.PageTableBase;
if (L4PageTable[Index4] == 0) {
*PageAttribute = PageNone;
return NULL;
}
L3PageTable = (UINT64 *)(UINTN)(L4PageTable[Index4] & ~AddressEncMask & PAGING_4K_ADDRESS_MASK_64);
} else {
ASSERT((PagingContext->ContextData.Ia32.Attributes & PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAE) != 0);
L3PageTable = (UINT64 *)(UINTN)PagingContext->ContextData.Ia32.PageTableBase;
}
if (L3PageTable[Index3] == 0) {
*PageAttribute = PageNone;
return NULL;
}
if ((L3PageTable[Index3] & IA32_PG_PS) != 0) {
// 1G
*PageAttribute = Page1G;
return &L3PageTable[Index3];
}
L2PageTable = (UINT64 *)(UINTN)(L3PageTable[Index3] & ~AddressEncMask & PAGING_4K_ADDRESS_MASK_64);
if (L2PageTable[Index2] == 0) {
*PageAttribute = PageNone;
return NULL;
}
if ((L2PageTable[Index2] & IA32_PG_PS) != 0) {
// 2M
*PageAttribute = Page2M;
return &L2PageTable[Index2];
}
// 4k
L1PageTable = (UINT64 *)(UINTN)(L2PageTable[Index2] & ~AddressEncMask & PAGING_4K_ADDRESS_MASK_64);
if ((L1PageTable[Index1] == 0) && (Address != 0)) {
*PageAttribute = PageNone;
return NULL;
}
*PageAttribute = Page4K;
return &L1PageTable[Index1];
}
/**
Return memory attributes of page entry.
@param[in] PageEntry The page entry.
@return Memory attributes of page entry.
**/
UINT64
GetAttributesFromPageEntry (
IN UINT64 *PageEntry
)
{
UINT64 Attributes;
Attributes = 0;
if ((*PageEntry & IA32_PG_P) == 0) {
Attributes |= EFI_MEMORY_RP;
}
if ((*PageEntry & IA32_PG_RW) == 0) {
Attributes |= EFI_MEMORY_RO;
}
if ((*PageEntry & IA32_PG_NX) != 0) {
Attributes |= EFI_MEMORY_XP;
}
return Attributes;
}
/**
Modify memory attributes of page entry.
@param[in] PagingContext The paging context.
@param[in] PageEntry The page entry.
@param[in] Attributes The bit mask of attributes to modify for the memory region.
@param[in] PageAction The page action.
@param[out] IsModified TRUE means page table modified. FALSE means page table not modified.
**/
VOID
ConvertPageEntryAttribute (
IN PAGE_TABLE_LIB_PAGING_CONTEXT *PagingContext,
IN UINT64 *PageEntry,
IN UINT64 Attributes,
IN PAGE_ACTION PageAction,
OUT BOOLEAN *IsModified
)
{
UINT64 CurrentPageEntry;
UINT64 NewPageEntry;
CurrentPageEntry = *PageEntry;
NewPageEntry = CurrentPageEntry;
if ((Attributes & EFI_MEMORY_RP) != 0) {
switch (PageAction) {
case PageActionAssign:
case PageActionSet:
NewPageEntry &= ~(UINT64)IA32_PG_P;
break;
case PageActionClear:
NewPageEntry |= IA32_PG_P;
break;
}
} else {
switch (PageAction) {
case PageActionAssign:
NewPageEntry |= IA32_PG_P;
break;
case PageActionSet:
case PageActionClear:
break;
}
}
if ((Attributes & EFI_MEMORY_RO) != 0) {
switch (PageAction) {
case PageActionAssign:
case PageActionSet:
NewPageEntry &= ~(UINT64)IA32_PG_RW;
break;
case PageActionClear:
NewPageEntry |= IA32_PG_RW;
break;
}
} else {
switch (PageAction) {
case PageActionAssign:
NewPageEntry |= IA32_PG_RW;
break;
case PageActionSet:
case PageActionClear:
break;
}
}
if ((PagingContext->ContextData.Ia32.Attributes & PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_XD_ACTIVATED) != 0) {
if ((Attributes & EFI_MEMORY_XP) != 0) {
switch (PageAction) {
case PageActionAssign:
case PageActionSet:
NewPageEntry |= IA32_PG_NX;
break;
case PageActionClear:
NewPageEntry &= ~IA32_PG_NX;
break;
}
} else {
switch (PageAction) {
case PageActionAssign:
NewPageEntry &= ~IA32_PG_NX;
break;
case PageActionSet:
case PageActionClear:
break;
}
}
}
*PageEntry = NewPageEntry;
if (CurrentPageEntry != NewPageEntry) {
*IsModified = TRUE;
DEBUG ((DEBUG_VERBOSE, "ConvertPageEntryAttribute 0x%lx", CurrentPageEntry));
DEBUG ((DEBUG_VERBOSE, "->0x%lx\n", NewPageEntry));
} else {
*IsModified = FALSE;
}
}
/**
This function returns if there is need to split page entry.
@param[in] BaseAddress The base address to be checked.
@param[in] Length The length to be checked.
@param[in] PageEntry The page entry to be checked.
@param[in] PageAttribute The page attribute of the page entry.
@retval SplitAttributes on if there is need to split page entry.
**/
PAGE_ATTRIBUTE
NeedSplitPage (
IN PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length,
IN UINT64 *PageEntry,
IN PAGE_ATTRIBUTE PageAttribute
)
{
UINT64 PageEntryLength;
PageEntryLength = PageAttributeToLength (PageAttribute);
if (((BaseAddress & (PageEntryLength - 1)) == 0) && (Length >= PageEntryLength)) {
return PageNone;
}
if (((BaseAddress & PAGING_2M_MASK) != 0) || (Length < SIZE_2MB)) {
return Page4K;
}
return Page2M;
}
/**
This function splits one page entry to small page entries.
@param[in] PageEntry The page entry to be splitted.
@param[in] PageAttribute The page attribute of the page entry.
@param[in] SplitAttribute How to split the page entry.
@param[in] AllocatePagesFunc If page split is needed, this function is used to allocate more pages.
@retval RETURN_SUCCESS The page entry is splitted.
@retval RETURN_UNSUPPORTED The page entry does not support to be splitted.
@retval RETURN_OUT_OF_RESOURCES No resource to split page entry.
**/
RETURN_STATUS
SplitPage (
IN UINT64 *PageEntry,
IN PAGE_ATTRIBUTE PageAttribute,
IN PAGE_ATTRIBUTE SplitAttribute,
IN PAGE_TABLE_LIB_ALLOCATE_PAGES AllocatePagesFunc
)
{
UINT64 BaseAddress;
UINT64 *NewPageEntry;
UINTN Index;
UINT64 AddressEncMask;
ASSERT (PageAttribute == Page2M || PageAttribute == Page1G);
ASSERT (AllocatePagesFunc != NULL);
// Make sure AddressEncMask is contained to smallest supported address field.
//
AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) & PAGING_1G_ADDRESS_MASK_64;
if (PageAttribute == Page2M) {
//
// Split 2M to 4K
//
ASSERT (SplitAttribute == Page4K);
if (SplitAttribute == Page4K) {
NewPageEntry = AllocatePagesFunc (1);
DEBUG ((DEBUG_VERBOSE, "Split - 0x%x\n", NewPageEntry));
if (NewPageEntry == NULL) {
return RETURN_OUT_OF_RESOURCES;
}
BaseAddress = *PageEntry & ~AddressEncMask & PAGING_2M_ADDRESS_MASK_64;
for (Index = 0; Index < SIZE_4KB / sizeof(UINT64); Index++) {
NewPageEntry[Index] = (BaseAddress + SIZE_4KB * Index) | AddressEncMask | ((*PageEntry) & PAGE_PROGATE_BITS);
}
(*PageEntry) = (UINT64)(UINTN)NewPageEntry | AddressEncMask | ((*PageEntry) & PAGE_ATTRIBUTE_BITS);
return RETURN_SUCCESS;
} else {
return RETURN_UNSUPPORTED;
}
} else if (PageAttribute == Page1G) {
//
// Split 1G to 2M
// No need support 1G->4K directly, we should use 1G->2M, then 2M->4K to get more compact page table.
//
ASSERT (SplitAttribute == Page2M || SplitAttribute == Page4K);
if ((SplitAttribute == Page2M || SplitAttribute == Page4K)) {
NewPageEntry = AllocatePagesFunc (1);
DEBUG ((DEBUG_VERBOSE, "Split - 0x%x\n", NewPageEntry));
if (NewPageEntry == NULL) {
return RETURN_OUT_OF_RESOURCES;
}
BaseAddress = *PageEntry & ~AddressEncMask & PAGING_1G_ADDRESS_MASK_64;
for (Index = 0; Index < SIZE_4KB / sizeof(UINT64); Index++) {
NewPageEntry[Index] = (BaseAddress + SIZE_2MB * Index) | AddressEncMask | IA32_PG_PS | ((*PageEntry) & PAGE_PROGATE_BITS);
}
(*PageEntry) = (UINT64)(UINTN)NewPageEntry | AddressEncMask | ((*PageEntry) & PAGE_ATTRIBUTE_BITS);
return RETURN_SUCCESS;
} else {
return RETURN_UNSUPPORTED;
}
} else {
return RETURN_UNSUPPORTED;
}
}
/**
Check the WP status in CR0 register. This bit is used to lock or unlock write
access to pages marked as read-only.
@retval TRUE Write protection is enabled.
@retval FALSE Write protection is disabled.
**/
BOOLEAN
IsReadOnlyPageWriteProtected (
VOID
)
{
//
// To avoid unforseen consequences, don't touch paging settings in SMM mode
// in this driver.
//
if (!IsInSmm ()) {
return ((AsmReadCr0 () & CR0_WP) != 0);
}
return FALSE;
}
/**
Disable Write Protect on pages marked as read-only.
**/
VOID
DisableReadOnlyPageWriteProtect (
VOID
)
{
//
// To avoid unforseen consequences, don't touch paging settings in SMM mode
// in this driver.
//
if (!IsInSmm ()) {
AsmWriteCr0 (AsmReadCr0 () & ~CR0_WP);
}
}
/**
Enable Write Protect on pages marked as read-only.
**/
VOID
EnableReadOnlyPageWriteProtect (
VOID
)
{
//
// To avoid unforseen consequences, don't touch paging settings in SMM mode
// in this driver.
//
if (!IsInSmm ()) {
AsmWriteCr0 (AsmReadCr0 () | CR0_WP);
}
}
/**
This function modifies the page attributes for the memory region specified by BaseAddress and
Length from their current attributes to the attributes specified by Attributes.
Caller should make sure BaseAddress and Length is at page boundary.
@param[in] PagingContext The paging context. NULL means get page table from current CPU context.
@param[in] BaseAddress The physical address that is the start address of a memory region.
@param[in] Length The size in bytes of the memory region.
@param[in] Attributes The bit mask of attributes to modify for the memory region.
@param[in] PageAction The page action.
@param[in] AllocatePagesFunc If page split is needed, this function is used to allocate more pages.
NULL mean page split is unsupported.
@param[out] IsSplitted TRUE means page table splitted. FALSE means page table not splitted.
@param[out] IsModified TRUE means page table modified. FALSE means page table not modified.
@retval RETURN_SUCCESS The attributes were modified for the memory region.
@retval RETURN_ACCESS_DENIED The attributes for the memory resource range specified by
BaseAddress and Length cannot be modified.
@retval RETURN_INVALID_PARAMETER Length is zero.
Attributes specified an illegal combination of attributes that
cannot be set together.
@retval RETURN_OUT_OF_RESOURCES There are not enough system resources to modify the attributes of
the memory resource range.
@retval RETURN_UNSUPPORTED The processor does not support one or more bytes of the memory
resource range specified by BaseAddress and Length.
The bit mask of attributes is not support for the memory resource
range specified by BaseAddress and Length.
**/
RETURN_STATUS
ConvertMemoryPageAttributes (
IN PAGE_TABLE_LIB_PAGING_CONTEXT *PagingContext OPTIONAL,
IN PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length,
IN UINT64 Attributes,
IN PAGE_ACTION PageAction,
IN PAGE_TABLE_LIB_ALLOCATE_PAGES AllocatePagesFunc OPTIONAL,
OUT BOOLEAN *IsSplitted, OPTIONAL
OUT BOOLEAN *IsModified OPTIONAL
)
{
PAGE_TABLE_LIB_PAGING_CONTEXT CurrentPagingContext;
UINT64 *PageEntry;
PAGE_ATTRIBUTE PageAttribute;
UINTN PageEntryLength;
PAGE_ATTRIBUTE SplitAttribute;
RETURN_STATUS Status;
BOOLEAN IsEntryModified;
BOOLEAN IsWpEnabled;
if ((BaseAddress & (SIZE_4KB - 1)) != 0) {
DEBUG ((DEBUG_ERROR, "BaseAddress(0x%lx) is not aligned!\n", BaseAddress));
return EFI_UNSUPPORTED;
}
if ((Length & (SIZE_4KB - 1)) != 0) {
DEBUG ((DEBUG_ERROR, "Length(0x%lx) is not aligned!\n", Length));
return EFI_UNSUPPORTED;
}
if (Length == 0) {
DEBUG ((DEBUG_ERROR, "Length is 0!\n"));
return RETURN_INVALID_PARAMETER;
}
if ((Attributes & ~(EFI_MEMORY_RP | EFI_MEMORY_RO | EFI_MEMORY_XP)) != 0) {
DEBUG ((DEBUG_ERROR, "Attributes(0x%lx) has unsupported bit\n", Attributes));
return EFI_UNSUPPORTED;
}
if (PagingContext == NULL) {
GetCurrentPagingContext (&CurrentPagingContext);
} else {
CopyMem (&CurrentPagingContext, PagingContext, sizeof(CurrentPagingContext));
}
switch(CurrentPagingContext.MachineType) {
case IMAGE_FILE_MACHINE_I386:
if (CurrentPagingContext.ContextData.Ia32.PageTableBase == 0) {
if (Attributes == 0) {
return EFI_SUCCESS;
} else {
DEBUG ((DEBUG_ERROR, "PageTable is 0!\n"));
return EFI_UNSUPPORTED;
}
}
if ((CurrentPagingContext.ContextData.Ia32.Attributes & PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAE) == 0) {
DEBUG ((DEBUG_ERROR, "Non-PAE Paging!\n"));
return EFI_UNSUPPORTED;
}
if ((BaseAddress + Length) > BASE_4GB) {
DEBUG ((DEBUG_ERROR, "Beyond 4GB memory in 32-bit mode!\n"));
return EFI_UNSUPPORTED;
}
break;
case IMAGE_FILE_MACHINE_X64:
ASSERT (CurrentPagingContext.ContextData.X64.PageTableBase != 0);
break;
default:
ASSERT(FALSE);
return EFI_UNSUPPORTED;
break;
}
// DEBUG ((DEBUG_ERROR, "ConvertMemoryPageAttributes(%x) - %016lx, %016lx, %02lx\n", IsSet, BaseAddress, Length, Attributes));
if (IsSplitted != NULL) {
*IsSplitted = FALSE;
}
if (IsModified != NULL) {
*IsModified = FALSE;
}
if (AllocatePagesFunc == NULL) {
AllocatePagesFunc = AllocatePageTableMemory;
}
//
// Make sure that the page table is changeable.
//
IsWpEnabled = IsReadOnlyPageWriteProtected ();
if (IsWpEnabled) {
DisableReadOnlyPageWriteProtect ();
}
//
// Below logic is to check 2M/4K page to make sure we donot waist memory.
//
Status = EFI_SUCCESS;
while (Length != 0) {
PageEntry = GetPageTableEntry (&CurrentPagingContext, BaseAddress, &PageAttribute);
if (PageEntry == NULL) {
Status = RETURN_UNSUPPORTED;
goto Done;
}
PageEntryLength = PageAttributeToLength (PageAttribute);
SplitAttribute = NeedSplitPage (BaseAddress, Length, PageEntry, PageAttribute);
if (SplitAttribute == PageNone) {
ConvertPageEntryAttribute (&CurrentPagingContext, PageEntry, Attributes, PageAction, &IsEntryModified);
if (IsEntryModified) {
if (IsModified != NULL) {
*IsModified = TRUE;
}
}
//
// Convert success, move to next
//
BaseAddress += PageEntryLength;
Length -= PageEntryLength;
} else {
if (AllocatePagesFunc == NULL) {
Status = RETURN_UNSUPPORTED;
goto Done;
}
Status = SplitPage (PageEntry, PageAttribute, SplitAttribute, AllocatePagesFunc);
if (RETURN_ERROR (Status)) {
Status = RETURN_UNSUPPORTED;
goto Done;
}
if (IsSplitted != NULL) {
*IsSplitted = TRUE;
}
if (IsModified != NULL) {
*IsModified = TRUE;
}
//
// Just split current page
// Convert success in next around
//
}
}
Done:
//
// Restore page table write protection, if any.
//
if (IsWpEnabled) {
EnableReadOnlyPageWriteProtect ();
}
return Status;
}
/**
This function assigns the page attributes for the memory region specified by BaseAddress and
Length from their current attributes to the attributes specified by Attributes.
Caller should make sure BaseAddress and Length is at page boundary.
Caller need guarentee the TPL <= TPL_NOTIFY, if there is split page request.
@param[in] PagingContext The paging context. NULL means get page table from current CPU context.
@param[in] BaseAddress The physical address that is the start address of a memory region.
@param[in] Length The size in bytes of the memory region.
@param[in] Attributes The bit mask of attributes to set for the memory region.
@param[in] AllocatePagesFunc If page split is needed, this function is used to allocate more pages.
NULL mean page split is unsupported.
@retval RETURN_SUCCESS The attributes were cleared for the memory region.
@retval RETURN_ACCESS_DENIED The attributes for the memory resource range specified by
BaseAddress and Length cannot be modified.
@retval RETURN_INVALID_PARAMETER Length is zero.
Attributes specified an illegal combination of attributes that
cannot be set together.
@retval RETURN_OUT_OF_RESOURCES There are not enough system resources to modify the attributes of
the memory resource range.
@retval RETURN_UNSUPPORTED The processor does not support one or more bytes of the memory
resource range specified by BaseAddress and Length.
The bit mask of attributes is not support for the memory resource
range specified by BaseAddress and Length.
**/
RETURN_STATUS
EFIAPI
AssignMemoryPageAttributes (
IN PAGE_TABLE_LIB_PAGING_CONTEXT *PagingContext OPTIONAL,
IN PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length,
IN UINT64 Attributes,
IN PAGE_TABLE_LIB_ALLOCATE_PAGES AllocatePagesFunc OPTIONAL
)
{
RETURN_STATUS Status;
BOOLEAN IsModified;
BOOLEAN IsSplitted;
// DEBUG((DEBUG_INFO, "AssignMemoryPageAttributes: 0x%lx - 0x%lx (0x%lx)\n", BaseAddress, Length, Attributes));
Status = ConvertMemoryPageAttributes (PagingContext, BaseAddress, Length, Attributes, PageActionAssign, AllocatePagesFunc, &IsSplitted, &IsModified);
if (!EFI_ERROR(Status)) {
if ((PagingContext == NULL) && IsModified) {
//
// Flush TLB as last step.
//
// Note: Since APs will always init CR3 register in HLT loop mode or do
// TLB flush in MWAIT loop mode, there's no need to flush TLB for them
// here.
//
CpuFlushTlb();
}
}
return Status;
}
/**
Check if Execute Disable feature is enabled or not.
**/
BOOLEAN
IsExecuteDisableEnabled (
VOID
)
{
MSR_CORE_IA32_EFER_REGISTER MsrEfer;
MsrEfer.Uint64 = AsmReadMsr64 (MSR_IA32_EFER);
return (MsrEfer.Bits.NXE == 1);
}
/**
Update GCD memory space attributes according to current page table setup.
**/
VOID
RefreshGcdMemoryAttributesFromPaging (
VOID
)
{
EFI_STATUS Status;
UINTN NumberOfDescriptors;
EFI_GCD_MEMORY_SPACE_DESCRIPTOR *MemorySpaceMap;
PAGE_TABLE_LIB_PAGING_CONTEXT PagingContext;
PAGE_ATTRIBUTE PageAttribute;
UINT64 *PageEntry;
UINT64 PageLength;
UINT64 MemorySpaceLength;
UINT64 Length;
UINT64 BaseAddress;
UINT64 PageStartAddress;
UINT64 Attributes;
UINT64 Capabilities;
UINT64 NewAttributes;
UINTN Index;
//
// Assuming that memory space map returned is sorted already; otherwise sort
// them in the order of lowest address to highest address.
//
Status = gDS->GetMemorySpaceMap (&NumberOfDescriptors, &MemorySpaceMap);
ASSERT_EFI_ERROR (Status);
GetCurrentPagingContext (&PagingContext);
Attributes = 0;
NewAttributes = 0;
BaseAddress = 0;
PageLength = 0;
if (IsExecuteDisableEnabled ()) {
Capabilities = EFI_MEMORY_RO | EFI_MEMORY_RP | EFI_MEMORY_XP;
} else {
Capabilities = EFI_MEMORY_RO | EFI_MEMORY_RP;
}
for (Index = 0; Index < NumberOfDescriptors; Index++) {
if (MemorySpaceMap[Index].GcdMemoryType == EfiGcdMemoryTypeNonExistent) {
continue;
}
//
// Sync the actual paging related capabilities back to GCD service first.
// As a side effect (good one), this can also help to avoid unnecessary
// memory map entries due to the different capabilities of the same type
// memory, such as multiple RT_CODE and RT_DATA entries in memory map,
// which could cause boot failure of some old Linux distro (before v4.3).
//
Status = gDS->SetMemorySpaceCapabilities (
MemorySpaceMap[Index].BaseAddress,
MemorySpaceMap[Index].Length,
MemorySpaceMap[Index].Capabilities | Capabilities
);
if (EFI_ERROR (Status)) {
//
// If we cannot udpate the capabilities, we cannot update its
// attributes either. So just simply skip current block of memory.
//
DEBUG ((
DEBUG_WARN,
"Failed to update capability: [%lu] %016lx - %016lx (%016lx -> %016lx)\r\n",
(UINT64)Index, MemorySpaceMap[Index].BaseAddress,
MemorySpaceMap[Index].BaseAddress + MemorySpaceMap[Index].Length - 1,
MemorySpaceMap[Index].Capabilities,
MemorySpaceMap[Index].Capabilities | Capabilities
));
continue;
}
if (MemorySpaceMap[Index].BaseAddress >= (BaseAddress + PageLength)) {
//
// Current memory space starts at a new page. Resetting PageLength will
// trigger a retrieval of page attributes at new address.
//
PageLength = 0;
} else {
//
// In case current memory space is not adjacent to last one
//
PageLength -= (MemorySpaceMap[Index].BaseAddress - BaseAddress);
}
//
// Sync actual page attributes to GCD
//
BaseAddress = MemorySpaceMap[Index].BaseAddress;
MemorySpaceLength = MemorySpaceMap[Index].Length;
while (MemorySpaceLength > 0) {
if (PageLength == 0) {
PageEntry = GetPageTableEntry (&PagingContext, BaseAddress, &PageAttribute);
if (PageEntry == NULL) {
break;
}
//
// Note current memory space might start in the middle of a page
//
PageStartAddress = (*PageEntry) & (UINT64)PageAttributeToMask(PageAttribute);
PageLength = PageAttributeToLength (PageAttribute) - (BaseAddress - PageStartAddress);
Attributes = GetAttributesFromPageEntry (PageEntry);
}
Length = MIN (PageLength, MemorySpaceLength);
if (Attributes != (MemorySpaceMap[Index].Attributes &
EFI_MEMORY_PAGETYPE_MASK)) {
NewAttributes = (MemorySpaceMap[Index].Attributes &
~EFI_MEMORY_PAGETYPE_MASK) | Attributes;
Status = gDS->SetMemorySpaceAttributes (
BaseAddress,
Length,
NewAttributes
);
ASSERT_EFI_ERROR (Status);
DEBUG ((
DEBUG_VERBOSE,
"Updated memory space attribute: [%lu] %016lx - %016lx (%016lx -> %016lx)\r\n",
(UINT64)Index, BaseAddress, BaseAddress + Length - 1,
MemorySpaceMap[Index].Attributes,
NewAttributes
));
}
PageLength -= Length;
MemorySpaceLength -= Length;
BaseAddress += Length;
}
}
FreePool (MemorySpaceMap);
}
/**
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. Usually this won't happen
often in practice.
@param[in] 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;
BOOLEAN IsModified;
//
// 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);
//
// Mark the whole pool pages as read-only.
//
ConvertMemoryPageAttributes (
NULL,
(PHYSICAL_ADDRESS)(UINTN)Buffer,
EFI_PAGES_TO_SIZE (PoolPages),
EFI_MEMORY_RO,
PageActionSet,
AllocatePageTableMemory,
NULL,
&IsModified
);
ASSERT (IsModified == TRUE);
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 *
EFIAPI
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;
}
/**
Special handler for #DB exception, which will restore the page attributes
(not-present). It should work with #PF handler which will set pages to
'present'.
@param ExceptionType Exception type.
@param SystemContext Pointer to EFI_SYSTEM_CONTEXT.
**/
VOID
EFIAPI
DebugExceptionHandler (
IN EFI_EXCEPTION_TYPE ExceptionType,
IN EFI_SYSTEM_CONTEXT SystemContext
)
{
UINTN CpuIndex;
UINTN PFEntry;
BOOLEAN IsWpEnabled;
MpInitLibWhoAmI (&CpuIndex);
//
// Clear last PF entries
//
IsWpEnabled = IsReadOnlyPageWriteProtected ();
if (IsWpEnabled) {
DisableReadOnlyPageWriteProtect ();
}
for (PFEntry = 0; PFEntry < mPFEntryCount[CpuIndex]; PFEntry++) {
if (mLastPFEntryPointer[CpuIndex][PFEntry] != NULL) {
*mLastPFEntryPointer[CpuIndex][PFEntry] &= ~(UINT64)IA32_PG_P;
}
}
if (IsWpEnabled) {
EnableReadOnlyPageWriteProtect ();
}
//
// Reset page fault exception count for next page fault.
//
mPFEntryCount[CpuIndex] = 0;
//
// Flush TLB
//
CpuFlushTlb ();
//
// Clear TF in EFLAGS
//
if (mPagingContext.MachineType == IMAGE_FILE_MACHINE_I386) {
SystemContext.SystemContextIa32->Eflags &= (UINT32)~BIT8;
} else {
SystemContext.SystemContextX64->Rflags &= (UINT64)~BIT8;
}
}
/**
Special handler for #PF exception, which will set the pages which caused
#PF to be 'present'. The attribute of those pages should be restored in
the subsequent #DB handler.
@param ExceptionType Exception type.
@param SystemContext Pointer to EFI_SYSTEM_CONTEXT.
**/
VOID
EFIAPI
PageFaultExceptionHandler (
IN EFI_EXCEPTION_TYPE ExceptionType,
IN EFI_SYSTEM_CONTEXT SystemContext
)
{
EFI_STATUS Status;
UINT64 PFAddress;
PAGE_TABLE_LIB_PAGING_CONTEXT PagingContext;
PAGE_ATTRIBUTE PageAttribute;
UINT64 Attributes;
UINT64 *PageEntry;
UINTN Index;
UINTN CpuIndex;
UINTN PageNumber;
BOOLEAN NonStopMode;
PFAddress = AsmReadCr2 () & ~EFI_PAGE_MASK;
if (PFAddress < BASE_4KB) {
NonStopMode = NULL_DETECTION_NONSTOP_MODE ? TRUE : FALSE;
} else {
NonStopMode = HEAP_GUARD_NONSTOP_MODE ? TRUE : FALSE;
}
if (NonStopMode) {
MpInitLibWhoAmI (&CpuIndex);
GetCurrentPagingContext (&PagingContext);
//
// Memory operation cross page boundary, like "rep mov" instruction, will
// cause infinite loop between this and Debug Trap handler. We have to make
// sure that current page and the page followed are both in PRESENT state.
//
PageNumber = 2;
while (PageNumber > 0) {
PageEntry = GetPageTableEntry (&PagingContext, PFAddress, &PageAttribute);
ASSERT(PageEntry != NULL);
if (PageEntry != NULL) {
Attributes = GetAttributesFromPageEntry (PageEntry);
if ((Attributes & EFI_MEMORY_RP) != 0) {
Attributes &= ~EFI_MEMORY_RP;
Status = AssignMemoryPageAttributes (&PagingContext, PFAddress,
EFI_PAGE_SIZE, Attributes, NULL);
if (!EFI_ERROR(Status)) {
Index = mPFEntryCount[CpuIndex];
//
// Re-retrieve page entry because above calling might update page
// table due to table split.
//
PageEntry = GetPageTableEntry (&PagingContext, PFAddress, &PageAttribute);
mLastPFEntryPointer[CpuIndex][Index++] = PageEntry;
mPFEntryCount[CpuIndex] = Index;
}
}
}
PFAddress += EFI_PAGE_SIZE;
--PageNumber;
}
}
//
// Initialize the serial port before dumping.
//
SerialPortInitialize ();
//
// Display ExceptionType, CPU information and Image information
//
DumpCpuContext (ExceptionType, SystemContext);
if (!NonStopMode) {
CpuDeadLoop ();
}
}
/**
Initialize the Page Table lib.
**/
VOID
InitializePageTableLib (
VOID
)
{
PAGE_TABLE_LIB_PAGING_CONTEXT CurrentPagingContext;
GetCurrentPagingContext (&CurrentPagingContext);
//
// Reserve memory of page tables for future uses, if paging is enabled.
//
if (CurrentPagingContext.ContextData.X64.PageTableBase != 0 &&
(CurrentPagingContext.ContextData.Ia32.Attributes &
PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAE) != 0) {
DisableReadOnlyPageWriteProtect ();
InitializePageTablePool (1);
EnableReadOnlyPageWriteProtect ();
}
if (HEAP_GUARD_NONSTOP_MODE || NULL_DETECTION_NONSTOP_MODE) {
mPFEntryCount = (UINTN *)AllocateZeroPool (sizeof (UINTN) * mNumberOfProcessors);
ASSERT (mPFEntryCount != NULL);
mLastPFEntryPointer = (UINT64 *(*)[MAX_PF_ENTRY_COUNT])
AllocateZeroPool (sizeof (mLastPFEntryPointer[0]) * mNumberOfProcessors);
ASSERT (mLastPFEntryPointer != NULL);
}
DEBUG ((DEBUG_INFO, "CurrentPagingContext:\n", CurrentPagingContext.MachineType));
DEBUG ((DEBUG_INFO, " MachineType - 0x%x\n", CurrentPagingContext.MachineType));
DEBUG ((DEBUG_INFO, " PageTableBase - 0x%x\n", CurrentPagingContext.ContextData.X64.PageTableBase));
DEBUG ((DEBUG_INFO, " Attributes - 0x%x\n", CurrentPagingContext.ContextData.X64.Attributes));
return ;
}
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