2 UEFI Heap Guard functions.
4 Copyright (c) 2017-2018, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
15 #include "HeapGuard.h"
18 // Global to avoid infinite reentrance of memory allocation when updating
19 // page table attributes, which may need allocating pages for new PDE/PTE.
21 GLOBAL_REMOVE_IF_UNREFERENCED BOOLEAN mOnGuarding
= FALSE
;
24 // Pointer to table tracking the Guarded memory with bitmap, in which '1'
25 // is used to indicate memory guarded. '0' might be free memory or Guard
26 // page itself, depending on status of memory adjacent to it.
28 GLOBAL_REMOVE_IF_UNREFERENCED UINT64 mGuardedMemoryMap
= 0;
31 // Current depth level of map table pointed by mGuardedMemoryMap.
32 // mMapLevel must be initialized at least by 1. It will be automatically
33 // updated according to the address of memory just tracked.
35 GLOBAL_REMOVE_IF_UNREFERENCED UINTN mMapLevel
= 1;
38 // Shift and mask for each level of map table
40 GLOBAL_REMOVE_IF_UNREFERENCED UINTN mLevelShift
[GUARDED_HEAP_MAP_TABLE_DEPTH
]
41 = GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS
;
42 GLOBAL_REMOVE_IF_UNREFERENCED UINTN mLevelMask
[GUARDED_HEAP_MAP_TABLE_DEPTH
]
43 = GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS
;
46 // SMM memory attribute protocol
48 EDKII_SMM_MEMORY_ATTRIBUTE_PROTOCOL
*mSmmMemoryAttribute
= NULL
;
51 Set corresponding bits in bitmap table to 1 according to the address.
53 @param[in] Address Start address to set for.
54 @param[in] BitNumber Number of bits to set.
55 @param[in] BitMap Pointer to bitmap which covers the Address.
62 IN EFI_PHYSICAL_ADDRESS Address
,
73 StartBit
= (UINTN
)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
);
74 EndBit
= (StartBit
+ BitNumber
- 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
76 if ((StartBit
+ BitNumber
) >= GUARDED_HEAP_MAP_ENTRY_BITS
) {
77 Msbs
= (GUARDED_HEAP_MAP_ENTRY_BITS
- StartBit
) %
78 GUARDED_HEAP_MAP_ENTRY_BITS
;
79 Lsbs
= (EndBit
+ 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
80 Qwords
= (BitNumber
- Msbs
) / GUARDED_HEAP_MAP_ENTRY_BITS
;
88 *BitMap
|= LShiftU64 (LShiftU64 (1, Msbs
) - 1, StartBit
);
93 SetMem64 ((VOID
*)BitMap
, Qwords
* GUARDED_HEAP_MAP_ENTRY_BYTES
,
99 *BitMap
|= (LShiftU64 (1, Lsbs
) - 1);
104 Set corresponding bits in bitmap table to 0 according to the address.
106 @param[in] Address Start address to set for.
107 @param[in] BitNumber Number of bits to set.
108 @param[in] BitMap Pointer to bitmap which covers the Address.
115 IN EFI_PHYSICAL_ADDRESS Address
,
126 StartBit
= (UINTN
)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
);
127 EndBit
= (StartBit
+ BitNumber
- 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
129 if ((StartBit
+ BitNumber
) >= GUARDED_HEAP_MAP_ENTRY_BITS
) {
130 Msbs
= (GUARDED_HEAP_MAP_ENTRY_BITS
- StartBit
) %
131 GUARDED_HEAP_MAP_ENTRY_BITS
;
132 Lsbs
= (EndBit
+ 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
133 Qwords
= (BitNumber
- Msbs
) / GUARDED_HEAP_MAP_ENTRY_BITS
;
141 *BitMap
&= ~LShiftU64 (LShiftU64 (1, Msbs
) - 1, StartBit
);
146 SetMem64 ((VOID
*)BitMap
, Qwords
* GUARDED_HEAP_MAP_ENTRY_BYTES
, 0);
151 *BitMap
&= ~(LShiftU64 (1, Lsbs
) - 1);
156 Get corresponding bits in bitmap table according to the address.
158 The value of bit 0 corresponds to the status of memory at given Address.
159 No more than 64 bits can be retrieved in one call.
161 @param[in] Address Start address to retrieve bits for.
162 @param[in] BitNumber Number of bits to get.
163 @param[in] BitMap Pointer to bitmap which covers the Address.
165 @return An integer containing the bits information.
170 IN EFI_PHYSICAL_ADDRESS Address
,
181 ASSERT (BitNumber
<= GUARDED_HEAP_MAP_ENTRY_BITS
);
183 StartBit
= (UINTN
)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
);
184 EndBit
= (StartBit
+ BitNumber
- 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
186 if ((StartBit
+ BitNumber
) > GUARDED_HEAP_MAP_ENTRY_BITS
) {
187 Msbs
= GUARDED_HEAP_MAP_ENTRY_BITS
- StartBit
;
188 Lsbs
= (EndBit
+ 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
194 if (StartBit
== 0 && BitNumber
== GUARDED_HEAP_MAP_ENTRY_BITS
) {
197 Result
= RShiftU64((*BitMap
), StartBit
) & (LShiftU64(1, Msbs
) - 1);
200 Result
|= LShiftU64 ((*BitMap
) & (LShiftU64 (1, Lsbs
) - 1), Msbs
);
208 Helper function to allocate pages without Guard for internal uses.
210 @param[in] Pages Page number.
212 @return Address of memory allocated.
220 EFI_PHYSICAL_ADDRESS Memory
;
222 Status
= SmmInternalAllocatePages (AllocateAnyPages
, EfiRuntimeServicesData
,
223 Pages
, &Memory
, FALSE
);
224 if (EFI_ERROR (Status
)) {
228 return (VOID
*)(UINTN
)Memory
;
232 Locate the pointer of bitmap from the guarded memory bitmap tables, which
233 covers the given Address.
235 @param[in] Address Start address to search the bitmap for.
236 @param[in] AllocMapUnit Flag to indicate memory allocation for the table.
237 @param[out] BitMap Pointer to bitmap which covers the Address.
239 @return The bit number from given Address to the end of current map table.
242 FindGuardedMemoryMap (
243 IN EFI_PHYSICAL_ADDRESS Address
,
244 IN BOOLEAN AllocMapUnit
,
256 // Adjust current map table depth according to the address to access
258 while (AllocMapUnit
&&
259 mMapLevel
< GUARDED_HEAP_MAP_TABLE_DEPTH
&&
262 mLevelShift
[GUARDED_HEAP_MAP_TABLE_DEPTH
- mMapLevel
- 1]
265 if (mGuardedMemoryMap
!= 0) {
266 Size
= (mLevelMask
[GUARDED_HEAP_MAP_TABLE_DEPTH
- mMapLevel
- 1] + 1)
267 * GUARDED_HEAP_MAP_ENTRY_BYTES
;
268 MapMemory
= (UINT64
)(UINTN
)PageAlloc (EFI_SIZE_TO_PAGES (Size
));
269 ASSERT (MapMemory
!= 0);
271 SetMem ((VOID
*)(UINTN
)MapMemory
, Size
, 0);
273 *(UINT64
*)(UINTN
)MapMemory
= mGuardedMemoryMap
;
274 mGuardedMemoryMap
= MapMemory
;
281 GuardMap
= &mGuardedMemoryMap
;
282 for (Level
= GUARDED_HEAP_MAP_TABLE_DEPTH
- mMapLevel
;
283 Level
< GUARDED_HEAP_MAP_TABLE_DEPTH
;
286 if (*GuardMap
== 0) {
292 Size
= (mLevelMask
[Level
] + 1) * GUARDED_HEAP_MAP_ENTRY_BYTES
;
293 MapMemory
= (UINT64
)(UINTN
)PageAlloc (EFI_SIZE_TO_PAGES (Size
));
294 ASSERT (MapMemory
!= 0);
296 SetMem ((VOID
*)(UINTN
)MapMemory
, Size
, 0);
297 *GuardMap
= MapMemory
;
300 Index
= (UINTN
)RShiftU64 (Address
, mLevelShift
[Level
]);
301 Index
&= mLevelMask
[Level
];
302 GuardMap
= (UINT64
*)(UINTN
)((*GuardMap
) + Index
* sizeof (UINT64
));
306 BitsToUnitEnd
= GUARDED_HEAP_MAP_BITS
- GUARDED_HEAP_MAP_BIT_INDEX (Address
);
309 return BitsToUnitEnd
;
313 Set corresponding bits in bitmap table to 1 according to given memory range.
315 @param[in] Address Memory address to guard from.
316 @param[in] NumberOfPages Number of pages to guard.
322 SetGuardedMemoryBits (
323 IN EFI_PHYSICAL_ADDRESS Address
,
324 IN UINTN NumberOfPages
331 while (NumberOfPages
> 0) {
332 BitsToUnitEnd
= FindGuardedMemoryMap (Address
, TRUE
, &BitMap
);
333 ASSERT (BitMap
!= NULL
);
335 if (NumberOfPages
> BitsToUnitEnd
) {
337 Bits
= BitsToUnitEnd
;
339 Bits
= NumberOfPages
;
342 SetBits (Address
, Bits
, BitMap
);
344 NumberOfPages
-= Bits
;
345 Address
+= EFI_PAGES_TO_SIZE (Bits
);
350 Clear corresponding bits in bitmap table according to given memory range.
352 @param[in] Address Memory address to unset from.
353 @param[in] NumberOfPages Number of pages to unset guard.
359 ClearGuardedMemoryBits (
360 IN EFI_PHYSICAL_ADDRESS Address
,
361 IN UINTN NumberOfPages
368 while (NumberOfPages
> 0) {
369 BitsToUnitEnd
= FindGuardedMemoryMap (Address
, TRUE
, &BitMap
);
370 ASSERT (BitMap
!= NULL
);
372 if (NumberOfPages
> BitsToUnitEnd
) {
374 Bits
= BitsToUnitEnd
;
376 Bits
= NumberOfPages
;
379 ClearBits (Address
, Bits
, BitMap
);
381 NumberOfPages
-= Bits
;
382 Address
+= EFI_PAGES_TO_SIZE (Bits
);
387 Retrieve corresponding bits in bitmap table according to given memory range.
389 @param[in] Address Memory address to retrieve from.
390 @param[in] NumberOfPages Number of pages to retrieve.
392 @return An integer containing the guarded memory bitmap.
395 GetGuardedMemoryBits (
396 IN EFI_PHYSICAL_ADDRESS Address
,
397 IN UINTN NumberOfPages
406 ASSERT (NumberOfPages
<= GUARDED_HEAP_MAP_ENTRY_BITS
);
410 while (NumberOfPages
> 0) {
411 BitsToUnitEnd
= FindGuardedMemoryMap (Address
, FALSE
, &BitMap
);
413 if (NumberOfPages
> BitsToUnitEnd
) {
415 Bits
= BitsToUnitEnd
;
417 Bits
= NumberOfPages
;
420 if (BitMap
!= NULL
) {
421 Result
|= LShiftU64 (GetBits (Address
, Bits
, BitMap
), Shift
);
425 NumberOfPages
-= Bits
;
426 Address
+= EFI_PAGES_TO_SIZE (Bits
);
433 Get bit value in bitmap table for the given address.
435 @param[in] Address The address to retrieve for.
442 IN EFI_PHYSICAL_ADDRESS Address
447 FindGuardedMemoryMap (Address
, FALSE
, &GuardMap
);
448 if (GuardMap
!= NULL
) {
449 if (RShiftU64 (*GuardMap
,
450 GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
)) & 1) {
459 Set the bit in bitmap table for the given address.
461 @param[in] Address The address to set for.
468 IN EFI_PHYSICAL_ADDRESS Address
474 FindGuardedMemoryMap (Address
, TRUE
, &GuardMap
);
475 if (GuardMap
!= NULL
) {
476 BitMask
= LShiftU64 (1, GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
));
477 *GuardMap
|= BitMask
;
482 Clear the bit in bitmap table for the given address.
484 @param[in] Address The address to clear for.
491 IN EFI_PHYSICAL_ADDRESS Address
497 FindGuardedMemoryMap (Address
, TRUE
, &GuardMap
);
498 if (GuardMap
!= NULL
) {
499 BitMask
= LShiftU64 (1, GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
));
500 *GuardMap
&= ~BitMask
;
505 Check to see if the page at the given address is a Guard page or not.
507 @param[in] Address The address to check for.
509 @return TRUE The page at Address is a Guard page.
510 @return FALSE The page at Address is not a Guard page.
515 IN EFI_PHYSICAL_ADDRESS Address
521 // There must be at least one guarded page before and/or after given
522 // address if it's a Guard page. The bitmap pattern should be one of
525 BitMap
= GetGuardedMemoryBits (Address
- EFI_PAGE_SIZE
, 3);
526 return ((BitMap
== BIT0
) || (BitMap
== BIT2
) || (BitMap
== (BIT2
| BIT0
)));
530 Check to see if the page at the given address is a head Guard page or not.
532 @param[in] Address The address to check for.
534 @return TRUE The page at Address is a head Guard page.
535 @return FALSE The page at Address is not a head Guard page.
540 IN EFI_PHYSICAL_ADDRESS Address
543 return (GetGuardedMemoryBits (Address
, 2) == BIT1
);
547 Check to see if the page at the given address is a tail Guard page or not.
549 @param[in] Address The address to check for.
551 @return TRUE The page at Address is a tail Guard page.
552 @return FALSE The page at Address is not a tail Guard page.
557 IN EFI_PHYSICAL_ADDRESS Address
560 return (GetGuardedMemoryBits (Address
- EFI_PAGE_SIZE
, 2) == BIT0
);
564 Check to see if the page at the given address is guarded or not.
566 @param[in] Address The address to check for.
568 @return TRUE The page at Address is guarded.
569 @return FALSE The page at Address is not guarded.
574 IN EFI_PHYSICAL_ADDRESS Address
577 return (GetGuardMapBit (Address
) == 1);
581 Set the page at the given address to be a Guard page.
583 This is done by changing the page table attribute to be NOT PRSENT.
585 @param[in] BaseAddress Page address to Guard at.
592 IN EFI_PHYSICAL_ADDRESS BaseAddress
595 if (mSmmMemoryAttribute
!= NULL
) {
597 mSmmMemoryAttribute
->SetMemoryAttributes (
608 Unset the Guard page at the given address to the normal memory.
610 This is done by changing the page table attribute to be PRSENT.
612 @param[in] BaseAddress Page address to Guard at.
619 IN EFI_PHYSICAL_ADDRESS BaseAddress
622 if (mSmmMemoryAttribute
!= NULL
) {
624 mSmmMemoryAttribute
->ClearMemoryAttributes (
635 Check to see if the memory at the given address should be guarded or not.
637 @param[in] MemoryType Memory type to check.
638 @param[in] AllocateType Allocation type to check.
639 @param[in] PageOrPool Indicate a page allocation or pool allocation.
642 @return TRUE The given type of memory should be guarded.
643 @return FALSE The given type of memory should not be guarded.
646 IsMemoryTypeToGuard (
647 IN EFI_MEMORY_TYPE MemoryType
,
648 IN EFI_ALLOCATE_TYPE AllocateType
,
655 if ((PcdGet8 (PcdHeapGuardPropertyMask
) & PageOrPool
) == 0
657 || AllocateType
== AllocateAddress
) {
662 if ((PageOrPool
& GUARD_HEAP_TYPE_POOL
) != 0) {
663 ConfigBit
|= PcdGet64 (PcdHeapGuardPoolType
);
666 if ((PageOrPool
& GUARD_HEAP_TYPE_PAGE
) != 0) {
667 ConfigBit
|= PcdGet64 (PcdHeapGuardPageType
);
670 if (MemoryType
== EfiRuntimeServicesData
||
671 MemoryType
== EfiRuntimeServicesCode
) {
672 TestBit
= LShiftU64 (1, MemoryType
);
673 } else if (MemoryType
== EfiMaxMemoryType
) {
674 TestBit
= (UINT64
)-1;
679 return ((ConfigBit
& TestBit
) != 0);
683 Check to see if the pool at the given address should be guarded or not.
685 @param[in] MemoryType Pool type to check.
688 @return TRUE The given type of pool should be guarded.
689 @return FALSE The given type of pool should not be guarded.
693 IN EFI_MEMORY_TYPE MemoryType
696 return IsMemoryTypeToGuard (MemoryType
, AllocateAnyPages
,
697 GUARD_HEAP_TYPE_POOL
);
701 Check to see if the page at the given address should be guarded or not.
703 @param[in] MemoryType Page type to check.
704 @param[in] AllocateType Allocation type to check.
706 @return TRUE The given type of page should be guarded.
707 @return FALSE The given type of page should not be guarded.
711 IN EFI_MEMORY_TYPE MemoryType
,
712 IN EFI_ALLOCATE_TYPE AllocateType
715 return IsMemoryTypeToGuard (MemoryType
, AllocateType
, GUARD_HEAP_TYPE_PAGE
);
719 Check to see if the heap guard is enabled for page and/or pool allocation.
728 return IsMemoryTypeToGuard (EfiMaxMemoryType
, AllocateAnyPages
,
729 GUARD_HEAP_TYPE_POOL
|GUARD_HEAP_TYPE_PAGE
);
733 Set head Guard and tail Guard for the given memory range.
735 @param[in] Memory Base address of memory to set guard for.
736 @param[in] NumberOfPages Memory size in pages.
742 IN EFI_PHYSICAL_ADDRESS Memory
,
743 IN UINTN NumberOfPages
746 EFI_PHYSICAL_ADDRESS GuardPage
;
751 GuardPage
= Memory
+ EFI_PAGES_TO_SIZE (NumberOfPages
);
752 if (!IsGuardPage (GuardPage
)) {
753 SetGuardPage (GuardPage
);
757 GuardPage
= Memory
- EFI_PAGES_TO_SIZE (1);
758 if (!IsGuardPage (GuardPage
)) {
759 SetGuardPage (GuardPage
);
763 // Mark the memory range as Guarded
765 SetGuardedMemoryBits (Memory
, NumberOfPages
);
769 Unset head Guard and tail Guard for the given memory range.
771 @param[in] Memory Base address of memory to unset guard for.
772 @param[in] NumberOfPages Memory size in pages.
777 UnsetGuardForMemory (
778 IN EFI_PHYSICAL_ADDRESS Memory
,
779 IN UINTN NumberOfPages
782 EFI_PHYSICAL_ADDRESS GuardPage
;
785 if (NumberOfPages
== 0) {
790 // Head Guard must be one page before, if any.
793 // -------------------
794 // Head Guard -> 0 1 -> Don't free Head Guard (shared Guard)
795 // Head Guard -> 0 0 -> Free Head Guard either (not shared Guard)
796 // 1 X -> Don't free first page (need a new Guard)
797 // (it'll be turned into a Guard page later)
798 // -------------------
801 GuardPage
= Memory
- EFI_PAGES_TO_SIZE (1);
802 GuardBitmap
= GetGuardedMemoryBits (Memory
- EFI_PAGES_TO_SIZE (2), 2);
803 if ((GuardBitmap
& BIT1
) == 0) {
805 // Head Guard exists.
807 if ((GuardBitmap
& BIT0
) == 0) {
809 // If the head Guard is not a tail Guard of adjacent memory block,
812 UnsetGuardPage (GuardPage
);
816 // Pages before memory to free are still in Guard. It's a partial free
817 // case. Turn first page of memory block to free into a new Guard.
819 SetGuardPage (Memory
);
823 // Tail Guard must be the page after this memory block to free, if any.
826 // --------------------
827 // 1 0 <- Tail Guard -> Don't free Tail Guard (shared Guard)
828 // 0 0 <- Tail Guard -> Free Tail Guard either (not shared Guard)
829 // X 1 -> Don't free last page (need a new Guard)
830 // (it'll be turned into a Guard page later)
831 // --------------------
834 GuardPage
= Memory
+ EFI_PAGES_TO_SIZE (NumberOfPages
);
835 GuardBitmap
= GetGuardedMemoryBits (GuardPage
, 2);
836 if ((GuardBitmap
& BIT0
) == 0) {
838 // Tail Guard exists.
840 if ((GuardBitmap
& BIT1
) == 0) {
842 // If the tail Guard is not a head Guard of adjacent memory block,
843 // free it; otherwise, keep it.
845 UnsetGuardPage (GuardPage
);
849 // Pages after memory to free are still in Guard. It's a partial free
850 // case. We need to keep one page to be a head Guard.
852 SetGuardPage (GuardPage
- EFI_PAGES_TO_SIZE (1));
856 // No matter what, we just clear the mark of the Guarded memory.
858 ClearGuardedMemoryBits(Memory
, NumberOfPages
);
862 Adjust address of free memory according to existing and/or required Guard.
864 This function will check if there're existing Guard pages of adjacent
865 memory blocks, and try to use it as the Guard page of the memory to be
868 @param[in] Start Start address of free memory block.
869 @param[in] Size Size of free memory block.
870 @param[in] SizeRequested Size of memory to allocate.
872 @return The end address of memory block found.
873 @return 0 if no enough space for the required size of memory and its Guard.
879 IN UINT64 SizeRequested
885 // UEFI spec requires that allocated pool must be 8-byte aligned. If it's
886 // indicated to put the pool near the Tail Guard, we need extra bytes to
887 // make sure alignment of the returned pool address.
889 if ((PcdGet8 (PcdHeapGuardPropertyMask
) & BIT7
) == 0) {
890 SizeRequested
= ALIGN_VALUE(SizeRequested
, 8);
893 Target
= Start
+ Size
- SizeRequested
;
894 ASSERT (Target
>= Start
);
899 if (!IsGuardPage (Start
+ Size
)) {
900 // No Guard at tail to share. One more page is needed.
901 Target
-= EFI_PAGES_TO_SIZE (1);
905 if (Target
< Start
) {
910 if (Target
== Start
) {
911 if (!IsGuardPage (Target
- EFI_PAGES_TO_SIZE (1))) {
912 // No enough space for a new head Guard if no Guard at head to share.
917 // OK, we have enough pages for memory and its Guards. Return the End of the
919 return Target
+ SizeRequested
- 1;
923 Adjust the start address and number of pages to free according to Guard.
925 The purpose of this function is to keep the shared Guard page with adjacent
926 memory block if it's still in guard, or free it if no more sharing. Another
927 is to reserve pages as Guard pages in partial page free situation.
929 @param[in,out] Memory Base address of memory to free.
930 @param[in,out] NumberOfPages Size of memory to free.
936 IN OUT EFI_PHYSICAL_ADDRESS
*Memory
,
937 IN OUT UINTN
*NumberOfPages
940 EFI_PHYSICAL_ADDRESS Start
;
941 EFI_PHYSICAL_ADDRESS MemoryToTest
;
946 if (Memory
== NULL
|| NumberOfPages
== NULL
|| *NumberOfPages
== 0) {
951 PagesToFree
= *NumberOfPages
;
954 // In case the memory to free is marked as read-only (e.g. EfiRuntimeServicesCode).
956 if (mSmmMemoryAttribute
!= NULL
) {
958 mSmmMemoryAttribute
->GetMemoryAttributes (
961 EFI_PAGES_TO_SIZE (PagesToFree
),
964 if ((Attributes
& EFI_MEMORY_RO
) != 0) {
965 mSmmMemoryAttribute
->ClearMemoryAttributes (
968 EFI_PAGES_TO_SIZE (PagesToFree
),
975 // Head Guard must be one page before, if any.
978 // -------------------
979 // Head Guard -> 0 1 -> Don't free Head Guard (shared Guard)
980 // Head Guard -> 0 0 -> Free Head Guard either (not shared Guard)
981 // 1 X -> Don't free first page (need a new Guard)
982 // (it'll be turned into a Guard page later)
983 // -------------------
986 MemoryToTest
= Start
- EFI_PAGES_TO_SIZE (2);
987 GuardBitmap
= GetGuardedMemoryBits (MemoryToTest
, 2);
988 if ((GuardBitmap
& BIT1
) == 0) {
990 // Head Guard exists.
992 if ((GuardBitmap
& BIT0
) == 0) {
994 // If the head Guard is not a tail Guard of adjacent memory block,
995 // free it; otherwise, keep it.
997 Start
-= EFI_PAGES_TO_SIZE (1);
1002 // No Head Guard, and pages before memory to free are still in Guard. It's a
1003 // partial free case. We need to keep one page to be a tail Guard.
1005 Start
+= EFI_PAGES_TO_SIZE (1);
1010 // Tail Guard must be the page after this memory block to free, if any.
1013 // --------------------
1014 // 1 0 <- Tail Guard -> Don't free Tail Guard (shared Guard)
1015 // 0 0 <- Tail Guard -> Free Tail Guard either (not shared Guard)
1016 // X 1 -> Don't free last page (need a new Guard)
1017 // (it'll be turned into a Guard page later)
1018 // --------------------
1021 MemoryToTest
= Start
+ EFI_PAGES_TO_SIZE (PagesToFree
);
1022 GuardBitmap
= GetGuardedMemoryBits (MemoryToTest
, 2);
1023 if ((GuardBitmap
& BIT0
) == 0) {
1025 // Tail Guard exists.
1027 if ((GuardBitmap
& BIT1
) == 0) {
1029 // If the tail Guard is not a head Guard of adjacent memory block,
1030 // free it; otherwise, keep it.
1034 } else if (PagesToFree
> 0) {
1036 // No Tail Guard, and pages after memory to free are still in Guard. It's a
1037 // partial free case. We need to keep one page to be a head Guard.
1043 *NumberOfPages
= PagesToFree
;
1047 Adjust the base and number of pages to really allocate according to Guard.
1049 @param[in,out] Memory Base address of free memory.
1050 @param[in,out] NumberOfPages Size of memory to allocate.
1056 IN OUT EFI_PHYSICAL_ADDRESS
*Memory
,
1057 IN OUT UINTN
*NumberOfPages
1061 // FindFreePages() has already taken the Guard into account. It's safe to
1062 // adjust the start address and/or number of pages here, to make sure that
1063 // the Guards are also "allocated".
1065 if (!IsGuardPage (*Memory
+ EFI_PAGES_TO_SIZE (*NumberOfPages
))) {
1066 // No tail Guard, add one.
1067 *NumberOfPages
+= 1;
1070 if (!IsGuardPage (*Memory
- EFI_PAGE_SIZE
)) {
1071 // No head Guard, add one.
1072 *Memory
-= EFI_PAGE_SIZE
;
1073 *NumberOfPages
+= 1;
1078 Adjust the pool head position to make sure the Guard page is adjavent to
1079 pool tail or pool head.
1081 @param[in] Memory Base address of memory allocated.
1082 @param[in] NoPages Number of pages actually allocated.
1083 @param[in] Size Size of memory requested.
1084 (plus pool head/tail overhead)
1086 @return Address of pool head
1090 IN EFI_PHYSICAL_ADDRESS Memory
,
1095 if (Memory
== 0 || (PcdGet8 (PcdHeapGuardPropertyMask
) & BIT7
) != 0) {
1097 // Pool head is put near the head Guard
1099 return (VOID
*)(UINTN
)Memory
;
1103 // Pool head is put near the tail Guard
1105 Size
= ALIGN_VALUE (Size
, 8);
1106 return (VOID
*)(UINTN
)(Memory
+ EFI_PAGES_TO_SIZE (NoPages
) - Size
);
1110 Get the page base address according to pool head address.
1112 @param[in] Memory Head address of pool to free.
1114 @return Address of pool head.
1118 IN EFI_PHYSICAL_ADDRESS Memory
1121 if (Memory
== 0 || (PcdGet8 (PcdHeapGuardPropertyMask
) & BIT7
) != 0) {
1123 // Pool head is put near the head Guard
1125 return (VOID
*)(UINTN
)Memory
;
1129 // Pool head is put near the tail Guard
1131 return (VOID
*)(UINTN
)(Memory
& ~EFI_PAGE_MASK
);
1135 Helper function of memory allocation with Guard pages.
1137 @param FreePageList The free page node.
1138 @param NumberOfPages Number of pages to be allocated.
1139 @param MaxAddress Request to allocate memory below this address.
1140 @param MemoryType Type of memory requested.
1142 @return Memory address of allocated pages.
1145 InternalAllocMaxAddressWithGuard (
1146 IN OUT LIST_ENTRY
*FreePageList
,
1147 IN UINTN NumberOfPages
,
1148 IN UINTN MaxAddress
,
1149 IN EFI_MEMORY_TYPE MemoryType
1154 FREE_PAGE_LIST
*Pages
;
1160 for (Node
= FreePageList
->BackLink
; Node
!= FreePageList
;
1161 Node
= Node
->BackLink
) {
1162 Pages
= BASE_CR (Node
, FREE_PAGE_LIST
, Link
);
1163 if (Pages
->NumberOfPages
>= NumberOfPages
&&
1164 (UINTN
)Pages
+ EFI_PAGES_TO_SIZE (NumberOfPages
) - 1 <= MaxAddress
) {
1167 // We may need 1 or 2 more pages for Guard. Check it out.
1169 PagesToAlloc
= NumberOfPages
;
1170 TailGuard
= (UINTN
)Pages
+ EFI_PAGES_TO_SIZE (Pages
->NumberOfPages
);
1171 if (!IsGuardPage (TailGuard
)) {
1173 // Add one if no Guard at the end of current free memory block.
1179 HeadGuard
= (UINTN
)Pages
+
1180 EFI_PAGES_TO_SIZE (Pages
->NumberOfPages
- PagesToAlloc
) -
1182 if (!IsGuardPage (HeadGuard
)) {
1184 // Add one if no Guard at the page before the address to allocate
1190 if (Pages
->NumberOfPages
< PagesToAlloc
) {
1191 // Not enough space to allocate memory with Guards? Try next block.
1195 Address
= InternalAllocPagesOnOneNode (Pages
, PagesToAlloc
, MaxAddress
);
1196 ConvertSmmMemoryMapEntry(MemoryType
, Address
, PagesToAlloc
, FALSE
);
1197 CoreFreeMemoryMapStack();
1198 if (HeadGuard
== 0) {
1199 // Don't pass the Guard page to user.
1200 Address
+= EFI_PAGE_SIZE
;
1202 SetGuardForMemory (Address
, NumberOfPages
);
1211 Helper function of memory free with Guard pages.
1213 @param[in] Memory Base address of memory being freed.
1214 @param[in] NumberOfPages The number of pages to free.
1215 @param[in] AddRegion If this memory is new added region.
1217 @retval EFI_NOT_FOUND Could not find the entry that covers the range.
1218 @retval EFI_INVALID_PARAMETER Address not aligned, Address is zero or NumberOfPages is zero.
1219 @return EFI_SUCCESS Pages successfully freed.
1222 SmmInternalFreePagesExWithGuard (
1223 IN EFI_PHYSICAL_ADDRESS Memory
,
1224 IN UINTN NumberOfPages
,
1225 IN BOOLEAN AddRegion
1228 EFI_PHYSICAL_ADDRESS MemoryToFree
;
1231 if (((Memory
& EFI_PAGE_MASK
) != 0) || (Memory
== 0) || (NumberOfPages
== 0)) {
1232 return EFI_INVALID_PARAMETER
;
1235 MemoryToFree
= Memory
;
1236 PagesToFree
= NumberOfPages
;
1238 AdjustMemoryF (&MemoryToFree
, &PagesToFree
);
1239 UnsetGuardForMemory (Memory
, NumberOfPages
);
1240 if (PagesToFree
== 0) {
1244 return SmmInternalFreePagesEx (MemoryToFree
, PagesToFree
, AddRegion
);
1248 Set all Guard pages which cannot be set during the non-SMM mode time.
1255 UINTN Entries
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1256 UINTN Shifts
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1257 UINTN Indices
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1258 UINT64 Tables
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1259 UINT64 Addresses
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1267 if (mGuardedMemoryMap
== 0 ||
1269 mMapLevel
> GUARDED_HEAP_MAP_TABLE_DEPTH
) {
1273 CopyMem (Entries
, mLevelMask
, sizeof (Entries
));
1274 CopyMem (Shifts
, mLevelShift
, sizeof (Shifts
));
1276 SetMem (Tables
, sizeof(Tables
), 0);
1277 SetMem (Addresses
, sizeof(Addresses
), 0);
1278 SetMem (Indices
, sizeof(Indices
), 0);
1280 Level
= GUARDED_HEAP_MAP_TABLE_DEPTH
- mMapLevel
;
1281 Tables
[Level
] = mGuardedMemoryMap
;
1286 DumpGuardedMemoryBitmap ();
1290 if (Indices
[Level
] > Entries
[Level
]) {
1295 TableEntry
= ((UINT64
*)(UINTN
)(Tables
[Level
]))[Indices
[Level
]];
1296 Address
= Addresses
[Level
];
1298 if (TableEntry
== 0) {
1302 } else if (Level
< GUARDED_HEAP_MAP_TABLE_DEPTH
- 1) {
1305 Tables
[Level
] = TableEntry
;
1306 Addresses
[Level
] = Address
;
1314 while (Index
< GUARDED_HEAP_MAP_ENTRY_BITS
) {
1315 if ((TableEntry
& 1) == 1) {
1319 GuardPage
= Address
- EFI_PAGE_SIZE
;
1324 GuardPage
= Address
;
1331 if (GuardPage
!= 0) {
1332 SetGuardPage (GuardPage
);
1335 if (TableEntry
== 0) {
1339 TableEntry
= RShiftU64 (TableEntry
, 1);
1340 Address
+= EFI_PAGE_SIZE
;
1346 if (Level
< (GUARDED_HEAP_MAP_TABLE_DEPTH
- (INTN
)mMapLevel
)) {
1350 Indices
[Level
] += 1;
1351 Address
= (Level
== 0) ? 0 : Addresses
[Level
- 1];
1352 Addresses
[Level
] = Address
| LShiftU64(Indices
[Level
], Shifts
[Level
]);
1358 Hook function used to set all Guard pages after entering SMM mode.
1361 SmmEntryPointMemoryManagementHook (
1367 if (mSmmMemoryAttribute
== NULL
) {
1368 Status
= SmmLocateProtocol (
1369 &gEdkiiSmmMemoryAttributeProtocolGuid
,
1371 (VOID
**)&mSmmMemoryAttribute
1373 if (!EFI_ERROR(Status
)) {
1374 SetAllGuardPages ();
1380 Helper function to convert a UINT64 value in binary to a string.
1382 @param[in] Value Value of a UINT64 integer.
1383 @param[out] BinString String buffer to contain the conversion result.
1390 OUT CHAR8
*BinString
1395 if (BinString
== NULL
) {
1399 for (Index
= 64; Index
> 0; --Index
) {
1400 BinString
[Index
- 1] = '0' + (Value
& 1);
1401 Value
= RShiftU64 (Value
, 1);
1403 BinString
[64] = '\0';
1407 Dump the guarded memory bit map.
1411 DumpGuardedMemoryBitmap (
1415 UINTN Entries
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1416 UINTN Shifts
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1417 UINTN Indices
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1418 UINT64 Tables
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1419 UINT64 Addresses
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1424 CHAR8 String
[GUARDED_HEAP_MAP_ENTRY_BITS
+ 1];
1428 if (mGuardedMemoryMap
== 0 ||
1430 mMapLevel
> GUARDED_HEAP_MAP_TABLE_DEPTH
) {
1434 Ruler1
= " 3 2 1 0";
1435 Ruler2
= "FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210";
1437 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, "============================="
1438 " Guarded Memory Bitmap "
1439 "==============================\r\n"));
1440 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, " %a\r\n", Ruler1
));
1441 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, " %a\r\n", Ruler2
));
1443 CopyMem (Entries
, mLevelMask
, sizeof (Entries
));
1444 CopyMem (Shifts
, mLevelShift
, sizeof (Shifts
));
1446 SetMem (Indices
, sizeof(Indices
), 0);
1447 SetMem (Tables
, sizeof(Tables
), 0);
1448 SetMem (Addresses
, sizeof(Addresses
), 0);
1450 Level
= GUARDED_HEAP_MAP_TABLE_DEPTH
- mMapLevel
;
1451 Tables
[Level
] = mGuardedMemoryMap
;
1456 if (Indices
[Level
] > Entries
[Level
]) {
1463 HEAP_GUARD_DEBUG_LEVEL
,
1464 "========================================="
1465 "=========================================\r\n"
1470 TableEntry
= ((UINT64
*)(UINTN
)Tables
[Level
])[Indices
[Level
]];
1471 Address
= Addresses
[Level
];
1473 if (TableEntry
== 0) {
1475 if (Level
== GUARDED_HEAP_MAP_TABLE_DEPTH
- 1) {
1476 if (RepeatZero
== 0) {
1477 Uint64ToBinString(TableEntry
, String
);
1478 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, "%016lx: %a\r\n", Address
, String
));
1479 } else if (RepeatZero
== 1) {
1480 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, "... : ...\r\n"));
1485 } else if (Level
< GUARDED_HEAP_MAP_TABLE_DEPTH
- 1) {
1488 Tables
[Level
] = TableEntry
;
1489 Addresses
[Level
] = Address
;
1498 Uint64ToBinString(TableEntry
, String
);
1499 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, "%016lx: %a\r\n", Address
, String
));
1504 if (Level
< (GUARDED_HEAP_MAP_TABLE_DEPTH
- (INTN
)mMapLevel
)) {
1508 Indices
[Level
] += 1;
1509 Address
= (Level
== 0) ? 0 : Addresses
[Level
- 1];
1510 Addresses
[Level
] = Address
| LShiftU64(Indices
[Level
], Shifts
[Level
]);
1516 Debug function used to verify if the Guard page is well set or not.
1518 @param[in] BaseAddress Address of memory to check.
1519 @param[in] NumberOfPages Size of memory in pages.
1521 @return TRUE The head Guard and tail Guard are both well set.
1522 @return FALSE The head Guard and/or tail Guard are not well set.
1526 IN EFI_PHYSICAL_ADDRESS BaseAddress
,
1527 IN UINTN NumberOfPages
1532 EFI_PHYSICAL_ADDRESS Address
;
1534 if (mSmmMemoryAttribute
== NULL
) {
1539 Address
= BaseAddress
- EFI_PAGE_SIZE
;
1540 Status
= mSmmMemoryAttribute
->GetMemoryAttributes (
1541 mSmmMemoryAttribute
,
1546 if (EFI_ERROR (Status
) || (Attribute
& EFI_MEMORY_RP
) == 0) {
1547 DEBUG ((DEBUG_ERROR
, "Head Guard is not set at: %016lx (%016lX)!!!\r\n",
1548 Address
, Attribute
));
1549 DumpGuardedMemoryBitmap ();
1554 Address
= BaseAddress
+ EFI_PAGES_TO_SIZE (NumberOfPages
);
1555 Status
= mSmmMemoryAttribute
->GetMemoryAttributes (
1556 mSmmMemoryAttribute
,
1561 if (EFI_ERROR (Status
) || (Attribute
& EFI_MEMORY_RP
) == 0) {
1562 DEBUG ((DEBUG_ERROR
, "Tail Guard is not set at: %016lx (%016lX)!!!\r\n",
1563 Address
, Attribute
));
1564 DumpGuardedMemoryBitmap ();