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audk/UefiCpuPkg/CpuMpPei/CpuPaging.c

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/** @file
Basic paging support for the CPU to enable Stack Guard.
Copyright (c) 2018 - 2019, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Register/Intel/Cpuid.h>
#include <Register/Intel/Msr.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/CpuLib.h>
#include <Library/BaseLib.h>
#include <Guid/MigratedFvInfo.h>
#include "CpuMpPei.h"
#define IA32_PG_P BIT0
#define IA32_PG_RW BIT1
#define IA32_PG_U BIT2
#define IA32_PG_A BIT5
#define IA32_PG_D BIT6
#define IA32_PG_PS BIT7
#define IA32_PG_NX BIT63
#define PAGE_ATTRIBUTE_BITS (IA32_PG_RW | IA32_PG_P)
#define PAGE_PROGATE_BITS (IA32_PG_D | IA32_PG_A | IA32_PG_NX | IA32_PG_U | \
PAGE_ATTRIBUTE_BITS)
#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 PAGING_512G_ADDRESS_MASK_64 0x000FFF8000000000ull
typedef enum {
PageNone = 0,
PageMin = 1,
Page4K = PageMin,
Page2M = 2,
Page1G = 3,
Page512G = 4,
PageMax = Page512G
} PAGE_ATTRIBUTE;
typedef struct {
PAGE_ATTRIBUTE Attribute;
UINT64 Length;
UINT64 AddressMask;
UINTN AddressBitOffset;
UINTN AddressBitLength;
} PAGE_ATTRIBUTE_TABLE;
PAGE_ATTRIBUTE_TABLE mPageAttributeTable[] = {
{ PageNone, 0, 0, 0, 0 },
{ Page4K, SIZE_4KB, PAGING_4K_ADDRESS_MASK_64, 12, 9 },
{ Page2M, SIZE_2MB, PAGING_2M_ADDRESS_MASK_64, 21, 9 },
{ Page1G, SIZE_1GB, PAGING_1G_ADDRESS_MASK_64, 30, 9 },
{ Page512G, SIZE_512GB, PAGING_512G_ADDRESS_MASK_64, 39, 9 },
};
EFI_PEI_NOTIFY_DESCRIPTOR mPostMemNotifyList[] = {
{
(EFI_PEI_PPI_DESCRIPTOR_NOTIFY_CALLBACK | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
&gEfiPeiMemoryDiscoveredPpiGuid,
MemoryDiscoveredPpiNotifyCallback
}
};
/**
The function will check if IA32 PAE is supported.
@retval TRUE IA32 PAE is supported.
@retval FALSE IA32 PAE is not supported.
**/
BOOLEAN
IsIa32PaeSupported (
VOID
)
{
UINT32 RegEax;
CPUID_VERSION_INFO_EDX RegEdx;
AsmCpuid (CPUID_SIGNATURE, &RegEax, NULL, NULL, NULL);
if (RegEax >= CPUID_VERSION_INFO) {
AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, NULL, &RegEdx.Uint32);
if (RegEdx.Bits.PAE != 0) {
return TRUE;
}
}
return FALSE;
}
/**
This API provides a way to allocate memory for page table.
@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 *Address;
Address = AllocatePages (Pages);
if (Address != NULL) {
ZeroMem (Address, EFI_PAGES_TO_SIZE (Pages));
}
return Address;
}
/**
Get the type of top level page table.
@retval Page512G PML4 paging.
@retval Page1G PAE paging.
**/
PAGE_ATTRIBUTE
GetPageTableTopLevelType (
VOID
)
{
MSR_IA32_EFER_REGISTER MsrEfer;
MsrEfer.Uint64 = AsmReadMsr64 (MSR_CORE_IA32_EFER);
return (MsrEfer.Bits.LMA == 1) ? Page512G : Page1G;
}
/**
Return page table entry matching the address.
@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 PHYSICAL_ADDRESS Address,
OUT PAGE_ATTRIBUTE *PageAttribute
)
{
INTN Level;
UINTN Index;
UINT64 *PageTable;
UINT64 AddressEncMask;
AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask);
PageTable = (UINT64 *)(UINTN)(AsmReadCr3 () & PAGING_4K_ADDRESS_MASK_64);
for (Level = (INTN)GetPageTableTopLevelType (); Level > 0; --Level) {
Index = (UINTN)RShiftU64 (Address, mPageAttributeTable[Level].AddressBitOffset);
Index &= PAGING_PAE_INDEX_MASK;
//
// No mapping?
//
if (PageTable[Index] == 0) {
*PageAttribute = PageNone;
return NULL;
}
//
// Page memory?
//
if (((PageTable[Index] & IA32_PG_PS) != 0) || (Level == PageMin)) {
*PageAttribute = (PAGE_ATTRIBUTE)Level;
return &PageTable[Index];
}
//
// Page directory or table
//
PageTable = (UINT64 *)(UINTN)(PageTable[Index] &
~AddressEncMask &
PAGING_4K_ADDRESS_MASK_64);
}
*PageAttribute = PageNone;
return NULL;
}
/**
This function splits one page entry to smaller 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] Recursively Do the split recursively or not.
@retval RETURN_SUCCESS The page entry is splitted.
@retval RETURN_INVALID_PARAMETER If target page attribute is invalid
@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 BOOLEAN Recursively
)
{
UINT64 BaseAddress;
UINT64 *NewPageEntry;
UINTN Index;
UINT64 AddressEncMask;
PAGE_ATTRIBUTE SplitTo;
if ((SplitAttribute == PageNone) || (SplitAttribute >= PageAttribute)) {
ASSERT (SplitAttribute != PageNone);
ASSERT (SplitAttribute < PageAttribute);
return RETURN_INVALID_PARAMETER;
}
NewPageEntry = AllocatePageTableMemory (1);
if (NewPageEntry == NULL) {
ASSERT (NewPageEntry != NULL);
return RETURN_OUT_OF_RESOURCES;
}
//
// One level down each step to achieve more compact page table.
//
SplitTo = PageAttribute - 1;
AddressEncMask = PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) &
mPageAttributeTable[SplitTo].AddressMask;
BaseAddress = *PageEntry &
~PcdGet64 (PcdPteMemoryEncryptionAddressOrMask) &
mPageAttributeTable[PageAttribute].AddressMask;
for (Index = 0; Index < SIZE_4KB / sizeof (UINT64); Index++) {
NewPageEntry[Index] = BaseAddress | AddressEncMask |
((*PageEntry) & PAGE_PROGATE_BITS);
if (SplitTo != PageMin) {
NewPageEntry[Index] |= IA32_PG_PS;
}
if (Recursively && (SplitTo > SplitAttribute)) {
SplitPage (&NewPageEntry[Index], SplitTo, SplitAttribute, Recursively);
}
BaseAddress += mPageAttributeTable[SplitTo].Length;
}
(*PageEntry) = (UINT64)(UINTN)NewPageEntry | AddressEncMask | PAGE_ATTRIBUTE_BITS;
return RETURN_SUCCESS;
}
/**
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] BaseAddress Start address of a memory region.
@param[in] Length Size in bytes of the memory region.
@param[in] Attributes Bit mask of attributes to modify.
@retval RETURN_SUCCESS The attributes were modified for the memory
region.
@retval RETURN_INVALID_PARAMETER Length is zero; or,
Attributes specified an illegal combination
of attributes that cannot be set together; or
Addressis not 4KB aligned.
@retval RETURN_OUT_OF_RESOURCES There are not enough system resources to modify
the attributes.
@retval RETURN_UNSUPPORTED Cannot modify the attributes of given memory.
**/
RETURN_STATUS
EFIAPI
ConvertMemoryPageAttributes (
IN PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length,
IN UINT64 Attributes
)
{
UINT64 *PageEntry;
PAGE_ATTRIBUTE PageAttribute;
RETURN_STATUS Status;
EFI_PHYSICAL_ADDRESS MaximumAddress;
if ((Length == 0) ||
((BaseAddress & (SIZE_4KB - 1)) != 0) ||
((Length & (SIZE_4KB - 1)) != 0))
{
ASSERT (Length > 0);
ASSERT ((BaseAddress & (SIZE_4KB - 1)) == 0);
ASSERT ((Length & (SIZE_4KB - 1)) == 0);
return RETURN_INVALID_PARAMETER;
}
MaximumAddress = (EFI_PHYSICAL_ADDRESS)MAX_UINT32;
if ((BaseAddress > MaximumAddress) ||
(Length > MaximumAddress) ||
(BaseAddress > MaximumAddress - (Length - 1)))
{
return RETURN_UNSUPPORTED;
}
//
// Below logic is to check 2M/4K page to make sure we do not waste memory.
//
while (Length != 0) {
PageEntry = GetPageTableEntry (BaseAddress, &PageAttribute);
if (PageEntry == NULL) {
return RETURN_UNSUPPORTED;
}
if (PageAttribute != Page4K) {
Status = SplitPage (PageEntry, PageAttribute, Page4K, FALSE);
if (RETURN_ERROR (Status)) {
return Status;
}
//
// Do it again until the page is 4K.
//
continue;
}
//
// Just take care of 'present' bit for Stack Guard.
//
if ((Attributes & IA32_PG_P) != 0) {
*PageEntry |= (UINT64)IA32_PG_P;
} else {
*PageEntry &= ~((UINT64)IA32_PG_P);
}
//
// Convert success, move to next
//
BaseAddress += SIZE_4KB;
Length -= SIZE_4KB;
}
return RETURN_SUCCESS;
}
/**
Enable PAE Page Table.
@retval EFI_SUCCESS The PAE Page Table was enabled successfully.
@retval EFI_OUT_OF_RESOURCES The PAE Page Table could not be enabled due to lack of available memory.
**/
EFI_STATUS
EnablePaePageTable (
VOID
)
{
EFI_STATUS Status;
UINTN PageTable;
VOID *Buffer;
UINTN BufferSize;
IA32_MAP_ATTRIBUTE MapAttribute;
IA32_MAP_ATTRIBUTE MapMask;
PageTable = 0;
Buffer = NULL;
BufferSize = 0;
MapAttribute.Uint64 = 0;
MapMask.Uint64 = MAX_UINT64;
MapAttribute.Bits.Present = 1;
MapAttribute.Bits.ReadWrite = 1;
//
// 1:1 map 4GB in 32bit mode
//
Status = PageTableMap (&PageTable, PagingPae, 0, &BufferSize, 0, SIZE_4GB, &MapAttribute, &MapMask, NULL);
ASSERT (Status == EFI_BUFFER_TOO_SMALL);
if (Status != EFI_BUFFER_TOO_SMALL) {
return Status;
}
//
// Allocate required Buffer.
//
Buffer = AllocatePageTableMemory (EFI_SIZE_TO_PAGES (BufferSize));
ASSERT (Buffer != NULL);
if (Buffer == NULL) {
return EFI_OUT_OF_RESOURCES;
}
Status = PageTableMap (&PageTable, PagingPae, Buffer, &BufferSize, 0, SIZE_4GB, &MapAttribute, &MapMask, NULL);
ASSERT_EFI_ERROR (Status);
if (EFI_ERROR (Status) || (PageTable == 0)) {
return EFI_OUT_OF_RESOURCES;
}
//
// Write the Pagetable to CR3.
//
AsmWriteCr3 (PageTable);
//
// Enable CR4.PAE
//
AsmWriteCr4 (AsmReadCr4 () | BIT5);
//
// Enable CR0.PG
//
AsmWriteCr0 (AsmReadCr0 () | BIT31);
DEBUG ((
DEBUG_INFO,
"EnablePaePageTable: Created PageTable = 0x%x, BufferSize = %x\n",
PageTable,
BufferSize
));
return Status;
}
/**
Get the base address of current AP's stack.
This function is called in AP's context and assumes that whole calling stacks
(till this function) consumed by AP's wakeup procedure will not exceed 4KB.
PcdCpuApStackSize must be configured with value taking the Guard page into
account.
@param[in,out] Buffer The pointer to private data buffer.
**/
VOID
EFIAPI
GetStackBase (
IN OUT VOID *Buffer
)
{
EFI_PHYSICAL_ADDRESS StackBase;
StackBase = (EFI_PHYSICAL_ADDRESS)(UINTN)&StackBase;
StackBase += BASE_4KB;
StackBase &= ~((EFI_PHYSICAL_ADDRESS)BASE_4KB - 1);
StackBase -= PcdGet32 (PcdCpuApStackSize);
*(EFI_PHYSICAL_ADDRESS *)Buffer = StackBase;
}
/**
Setup stack Guard page at the stack base of each processor. BSP and APs have
different way to get stack base address.
**/
VOID
SetupStackGuardPage (
VOID
)
{
EFI_PEI_HOB_POINTERS Hob;
EFI_PHYSICAL_ADDRESS StackBase;
UINTN NumberOfProcessors;
UINTN Bsp;
UINTN Index;
EFI_STATUS Status;
//
// One extra page at the bottom of the stack is needed for Guard page.
//
if (PcdGet32 (PcdCpuApStackSize) <= EFI_PAGE_SIZE) {
DEBUG ((DEBUG_ERROR, "PcdCpuApStackSize is not big enough for Stack Guard!\n"));
ASSERT (FALSE);
}
Status = MpInitLibGetNumberOfProcessors (&NumberOfProcessors, NULL);
ASSERT_EFI_ERROR (Status);
if (EFI_ERROR (Status)) {
NumberOfProcessors = 1;
}
MpInitLibWhoAmI (&Bsp);
for (Index = 0; Index < NumberOfProcessors; ++Index) {
StackBase = 0;
if (Index == Bsp) {
Hob.Raw = GetHobList ();
while ((Hob.Raw = GetNextHob (EFI_HOB_TYPE_MEMORY_ALLOCATION, Hob.Raw)) != NULL) {
if (CompareGuid (
&gEfiHobMemoryAllocStackGuid,
&(Hob.MemoryAllocationStack->AllocDescriptor.Name)
))
{
StackBase = Hob.MemoryAllocationStack->AllocDescriptor.MemoryBaseAddress;
break;
}
Hob.Raw = GET_NEXT_HOB (Hob);
}
} else {
//
// Ask AP to return is stack base address.
//
MpInitLibStartupThisAP (GetStackBase, Index, NULL, 0, (VOID *)&StackBase, NULL);
}
ASSERT (StackBase != 0);
//
// Set Guard page at stack base address.
//
ConvertMemoryPageAttributes (StackBase, EFI_PAGE_SIZE, 0);
DEBUG ((
DEBUG_INFO,
"Stack Guard set at %lx [cpu%lu]!\n",
(UINT64)StackBase,
(UINT64)Index
));
}
//
// Publish the changes of page table.
//
CpuFlushTlb ();
}
/**
Enable/setup stack guard for each processor if PcdCpuStackGuard is set to TRUE.
Doing this in the memory-discovered callback is to make sure the Stack Guard
feature to cover as most PEI code as possible.
@param[in] PeiServices General purpose services available to every PEIM.
@param[in] NotifyDescriptor The notification structure this PEIM registered on install.
@param[in] Ppi The memory discovered PPI. Not used.
@retval EFI_SUCCESS The function completed successfully.
@retval others There's error in MP initialization.
**/
EFI_STATUS
EFIAPI
MemoryDiscoveredPpiNotifyCallback (
IN EFI_PEI_SERVICES **PeiServices,
IN EFI_PEI_NOTIFY_DESCRIPTOR *NotifyDescriptor,
IN VOID *Ppi
)
{
EFI_STATUS Status;
BOOLEAN InitStackGuard;
EDKII_MIGRATED_FV_INFO *MigratedFvInfo;
EFI_PEI_HOB_POINTERS Hob;
IA32_CR0 Cr0;
//
// Paging must be setup first. Otherwise the exception TSS setup during MP
// initialization later will not contain paging information and then fail
// the task switch (for the sake of stack switch).
//
InitStackGuard = FALSE;
Hob.Raw = NULL;
if (IsIa32PaeSupported ()) {
Hob.Raw = GetFirstGuidHob (&gEdkiiMigratedFvInfoGuid);
InitStackGuard = PcdGetBool (PcdCpuStackGuard);
}
//
// Some security features depend on the page table enabling. So, here
// is to enable paging if it is not enabled (only in 32bit mode).
//
Cr0.UintN = AsmReadCr0 ();
if ((Cr0.Bits.PG == 0) && (InitStackGuard || (Hob.Raw != NULL))) {
ASSERT (sizeof (UINTN) == sizeof (UINT32));
Status = EnablePaePageTable ();
if (EFI_ERROR (Status)) {
DEBUG ((DEBUG_ERROR, "MemoryDiscoveredPpiNotifyCallback: Failed to enable PAE page table: %r.\n", Status));
CpuDeadLoop ();
}
}
Status = InitializeCpuMpWorker ((CONST EFI_PEI_SERVICES **)PeiServices);
ASSERT_EFI_ERROR (Status);
if (InitStackGuard) {
SetupStackGuardPage ();
}
while (Hob.Raw != NULL) {
MigratedFvInfo = GET_GUID_HOB_DATA (Hob);
//
// Enable #PF exception, so if the code access SPI after disable NEM, it will generate
// the exception to avoid potential vulnerability.
//
ConvertMemoryPageAttributes (MigratedFvInfo->FvOrgBase, MigratedFvInfo->FvLength, 0);
Hob.Raw = GET_NEXT_HOB (Hob);
Hob.Raw = GetNextGuidHob (&gEdkiiMigratedFvInfoGuid, Hob.Raw);
}
CpuFlushTlb ();
return Status;
}
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