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UefiCpuPkg/CpuDxe: implement non-stop mode for uefi

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Same as SMM profile feature, a special #PF is used to set page attribute
to 'present' and a special #DB handler to reset it back to 'not-present',
right after the instruction causing #PF got executed.

Since the new #PF handler won't enter into dead-loop, the instruction
which caused the #PF will get chance to re-execute with accessible pages.

The exception message will still be printed out on debug console so that
the developer/QA can find that there's potential heap overflow or null
pointer access occurred.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
This commit is contained in:
Jian J Wang
2018-08-20 11:31:00 +08:00
parent 16b918bbaf
commit dcc026217f
4 changed files with 237 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

167
UefiCpuPkg/CpuDxe/CpuPageTable.c
View File

@@ -22,6 +22,10 @@
#include <Library/MemoryAllocationLib.h>
#include <Library/DebugLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/PeCoffGetEntryPointLib.h>
#include <Library/SerialPortLib.h>
#include <Library/SynchronizationLib.h>
#include <Library/PrintLib.h>
#include <Protocol/MpService.h>
#include <Protocol/SmmBase2.h>
#include <Register/Cpuid.h>
@@ -73,6 +77,10 @@
#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,
@@ -102,6 +110,12 @@ 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.
@@ -1135,6 +1149,150 @@ AllocatePageTableMemory (
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] &= ~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.
**/
@@ -1158,6 +1316,15 @@ InitializePageTableLib (
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));