2 UEFI Heap Guard functions.
4 Copyright (c) 2017, 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.
17 #include "HeapGuard.h"
20 // Global to avoid infinite reentrance of memory allocation when updating
21 // page table attributes, which may need allocate pages for new PDE/PTE.
23 GLOBAL_REMOVE_IF_UNREFERENCED BOOLEAN mOnGuarding
= FALSE
;
26 // Pointer to table tracking the Guarded memory with bitmap, in which '1'
27 // is used to indicate memory guarded. '0' might be free memory or Guard
28 // page itself, depending on status of memory adjacent to it.
30 GLOBAL_REMOVE_IF_UNREFERENCED UINT64 mGuardedMemoryMap
= 0;
33 // Current depth level of map table pointed by mGuardedMemoryMap.
34 // mMapLevel must be initialized at least by 1. It will be automatically
35 // updated according to the address of memory just tracked.
37 GLOBAL_REMOVE_IF_UNREFERENCED UINTN mMapLevel
= 1;
40 // Shift and mask for each level of map table
42 GLOBAL_REMOVE_IF_UNREFERENCED UINTN mLevelShift
[GUARDED_HEAP_MAP_TABLE_DEPTH
]
43 = GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS
;
44 GLOBAL_REMOVE_IF_UNREFERENCED UINTN mLevelMask
[GUARDED_HEAP_MAP_TABLE_DEPTH
]
45 = GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS
;
48 Set corresponding bits in bitmap table to 1 according to the address.
50 @param[in] Address Start address to set for.
51 @param[in] BitNumber Number of bits to set.
52 @param[in] BitMap Pointer to bitmap which covers the Address.
59 IN EFI_PHYSICAL_ADDRESS Address
,
70 StartBit
= (UINTN
)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
);
71 EndBit
= (StartBit
+ BitNumber
- 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
73 if ((StartBit
+ BitNumber
) > GUARDED_HEAP_MAP_ENTRY_BITS
) {
74 Msbs
= (GUARDED_HEAP_MAP_ENTRY_BITS
- StartBit
) %
75 GUARDED_HEAP_MAP_ENTRY_BITS
;
76 Lsbs
= (EndBit
+ 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
77 Qwords
= (BitNumber
- Msbs
) / GUARDED_HEAP_MAP_ENTRY_BITS
;
85 *BitMap
|= LShiftU64 (LShiftU64 (1, Msbs
) - 1, StartBit
);
90 SetMem64 ((VOID
*)BitMap
, Qwords
* GUARDED_HEAP_MAP_ENTRY_BYTES
,
96 *BitMap
|= (LShiftU64 (1, Lsbs
) - 1);
101 Set corresponding bits in bitmap table to 0 according to the address.
103 @param[in] Address Start address to set for.
104 @param[in] BitNumber Number of bits to set.
105 @param[in] BitMap Pointer to bitmap which covers the Address.
112 IN EFI_PHYSICAL_ADDRESS Address
,
123 StartBit
= (UINTN
)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
);
124 EndBit
= (StartBit
+ BitNumber
- 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
126 if ((StartBit
+ BitNumber
) > GUARDED_HEAP_MAP_ENTRY_BITS
) {
127 Msbs
= (GUARDED_HEAP_MAP_ENTRY_BITS
- StartBit
) %
128 GUARDED_HEAP_MAP_ENTRY_BITS
;
129 Lsbs
= (EndBit
+ 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
130 Qwords
= (BitNumber
- Msbs
) / GUARDED_HEAP_MAP_ENTRY_BITS
;
138 *BitMap
&= ~LShiftU64 (LShiftU64 (1, Msbs
) - 1, StartBit
);
143 SetMem64 ((VOID
*)BitMap
, Qwords
* GUARDED_HEAP_MAP_ENTRY_BYTES
, 0);
148 *BitMap
&= ~(LShiftU64 (1, Lsbs
) - 1);
153 Get corresponding bits in bitmap table according to the address.
155 The value of bit 0 corresponds to the status of memory at given Address.
156 No more than 64 bits can be retrieved in one call.
158 @param[in] Address Start address to retrieve bits for.
159 @param[in] BitNumber Number of bits to get.
160 @param[in] BitMap Pointer to bitmap which covers the Address.
162 @return An integer containing the bits information.
167 IN EFI_PHYSICAL_ADDRESS Address
,
178 ASSERT (BitNumber
<= GUARDED_HEAP_MAP_ENTRY_BITS
);
180 StartBit
= (UINTN
)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
);
181 EndBit
= (StartBit
+ BitNumber
- 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
183 if ((StartBit
+ BitNumber
) > GUARDED_HEAP_MAP_ENTRY_BITS
) {
184 Msbs
= GUARDED_HEAP_MAP_ENTRY_BITS
- StartBit
;
185 Lsbs
= (EndBit
+ 1) % GUARDED_HEAP_MAP_ENTRY_BITS
;
191 Result
= RShiftU64 ((*BitMap
), StartBit
) & (LShiftU64 (1, Msbs
) - 1);
194 Result
|= LShiftU64 ((*BitMap
) & (LShiftU64 (1, Lsbs
) - 1), Msbs
);
201 Locate the pointer of bitmap from the guarded memory bitmap tables, which
202 covers the given Address.
204 @param[in] Address Start address to search the bitmap for.
205 @param[in] AllocMapUnit Flag to indicate memory allocation for the table.
206 @param[out] BitMap Pointer to bitmap which covers the Address.
208 @return The bit number from given Address to the end of current map table.
211 FindGuardedMemoryMap (
212 IN EFI_PHYSICAL_ADDRESS Address
,
213 IN BOOLEAN AllocMapUnit
,
226 // Adjust current map table depth according to the address to access
228 while (mMapLevel
< GUARDED_HEAP_MAP_TABLE_DEPTH
232 mLevelShift
[GUARDED_HEAP_MAP_TABLE_DEPTH
- mMapLevel
- 1]
235 if (mGuardedMemoryMap
!= 0) {
236 Size
= (mLevelMask
[GUARDED_HEAP_MAP_TABLE_DEPTH
- mMapLevel
- 1] + 1)
237 * GUARDED_HEAP_MAP_ENTRY_BYTES
;
238 Status
= CoreInternalAllocatePages (
241 EFI_SIZE_TO_PAGES (Size
),
245 ASSERT_EFI_ERROR (Status
);
246 ASSERT (MapMemory
!= 0);
248 SetMem ((VOID
*)(UINTN
)MapMemory
, Size
, 0);
250 *(UINT64
*)(UINTN
)MapMemory
= mGuardedMemoryMap
;
251 mGuardedMemoryMap
= MapMemory
;
258 GuardMap
= &mGuardedMemoryMap
;
259 for (Level
= GUARDED_HEAP_MAP_TABLE_DEPTH
- mMapLevel
;
260 Level
< GUARDED_HEAP_MAP_TABLE_DEPTH
;
263 if (*GuardMap
== 0) {
269 Size
= (mLevelMask
[Level
] + 1) * GUARDED_HEAP_MAP_ENTRY_BYTES
;
270 Status
= CoreInternalAllocatePages (
273 EFI_SIZE_TO_PAGES (Size
),
277 ASSERT_EFI_ERROR (Status
);
278 ASSERT (MapMemory
!= 0);
280 SetMem ((VOID
*)(UINTN
)MapMemory
, Size
, 0);
281 *GuardMap
= MapMemory
;
284 Index
= (UINTN
)RShiftU64 (Address
, mLevelShift
[Level
]);
285 Index
&= mLevelMask
[Level
];
286 GuardMap
= (UINT64
*)(UINTN
)((*GuardMap
) + Index
* sizeof (UINT64
));
290 BitsToUnitEnd
= GUARDED_HEAP_MAP_BITS
- GUARDED_HEAP_MAP_BIT_INDEX (Address
);
293 return BitsToUnitEnd
;
297 Set corresponding bits in bitmap table to 1 according to given memory range.
299 @param[in] Address Memory address to guard from.
300 @param[in] NumberOfPages Number of pages to guard.
306 SetGuardedMemoryBits (
307 IN EFI_PHYSICAL_ADDRESS Address
,
308 IN UINTN NumberOfPages
315 while (NumberOfPages
> 0) {
316 BitsToUnitEnd
= FindGuardedMemoryMap (Address
, TRUE
, &BitMap
);
317 ASSERT (BitMap
!= NULL
);
319 if (NumberOfPages
> BitsToUnitEnd
) {
321 Bits
= BitsToUnitEnd
;
323 Bits
= NumberOfPages
;
326 SetBits (Address
, Bits
, BitMap
);
328 NumberOfPages
-= Bits
;
329 Address
+= EFI_PAGES_TO_SIZE (Bits
);
334 Clear corresponding bits in bitmap table according to given memory range.
336 @param[in] Address Memory address to unset from.
337 @param[in] NumberOfPages Number of pages to unset guard.
343 ClearGuardedMemoryBits (
344 IN EFI_PHYSICAL_ADDRESS Address
,
345 IN UINTN NumberOfPages
352 while (NumberOfPages
> 0) {
353 BitsToUnitEnd
= FindGuardedMemoryMap (Address
, TRUE
, &BitMap
);
354 ASSERT (BitMap
!= NULL
);
356 if (NumberOfPages
> BitsToUnitEnd
) {
358 Bits
= BitsToUnitEnd
;
360 Bits
= NumberOfPages
;
363 ClearBits (Address
, Bits
, BitMap
);
365 NumberOfPages
-= Bits
;
366 Address
+= EFI_PAGES_TO_SIZE (Bits
);
371 Retrieve corresponding bits in bitmap table according to given memory range.
373 @param[in] Address Memory address to retrieve from.
374 @param[in] NumberOfPages Number of pages to retrieve.
376 @return An integer containing the guarded memory bitmap.
379 GetGuardedMemoryBits (
380 IN EFI_PHYSICAL_ADDRESS Address
,
381 IN UINTN NumberOfPages
390 ASSERT (NumberOfPages
<= GUARDED_HEAP_MAP_ENTRY_BITS
);
394 while (NumberOfPages
> 0) {
395 BitsToUnitEnd
= FindGuardedMemoryMap (Address
, FALSE
, &BitMap
);
397 if (NumberOfPages
> BitsToUnitEnd
) {
399 Bits
= BitsToUnitEnd
;
401 Bits
= NumberOfPages
;
404 if (BitMap
!= NULL
) {
405 Result
|= LShiftU64 (GetBits (Address
, Bits
, BitMap
), Shift
);
409 NumberOfPages
-= Bits
;
410 Address
+= EFI_PAGES_TO_SIZE (Bits
);
417 Get bit value in bitmap table for the given address.
419 @param[in] Address The address to retrieve for.
426 IN EFI_PHYSICAL_ADDRESS Address
431 FindGuardedMemoryMap (Address
, FALSE
, &GuardMap
);
432 if (GuardMap
!= NULL
) {
433 if (RShiftU64 (*GuardMap
,
434 GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
)) & 1) {
443 Set the bit in bitmap table for the given address.
445 @param[in] Address The address to set for.
452 IN EFI_PHYSICAL_ADDRESS Address
458 FindGuardedMemoryMap (Address
, TRUE
, &GuardMap
);
459 if (GuardMap
!= NULL
) {
460 BitMask
= LShiftU64 (1, GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
));
461 *GuardMap
|= BitMask
;
466 Clear the bit in bitmap table for the given address.
468 @param[in] Address The address to clear for.
475 IN EFI_PHYSICAL_ADDRESS Address
481 FindGuardedMemoryMap (Address
, TRUE
, &GuardMap
);
482 if (GuardMap
!= NULL
) {
483 BitMask
= LShiftU64 (1, GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address
));
484 *GuardMap
&= ~BitMask
;
489 Check to see if the page at the given address is a Guard page or not.
491 @param[in] Address The address to check for.
493 @return TRUE The page at Address is a Guard page.
494 @return FALSE The page at Address is not a Guard page.
499 IN EFI_PHYSICAL_ADDRESS Address
505 // There must be at least one guarded page before and/or after given
506 // address if it's a Guard page. The bitmap pattern should be one of
509 BitMap
= GetGuardedMemoryBits (Address
- EFI_PAGE_SIZE
, 3);
510 return ((BitMap
== BIT0
) || (BitMap
== BIT2
) || (BitMap
== (BIT2
| BIT0
)));
514 Check to see if the page at the given address is a head Guard page or not.
516 @param[in] Address The address to check for
518 @return TRUE The page at Address is a head Guard page
519 @return FALSE The page at Address is not a head Guard page
524 IN EFI_PHYSICAL_ADDRESS Address
527 return (GetGuardedMemoryBits (Address
, 2) == BIT1
);
531 Check to see if the page at the given address is a tail Guard page or not.
533 @param[in] Address The address to check for.
535 @return TRUE The page at Address is a tail Guard page.
536 @return FALSE The page at Address is not a tail Guard page.
541 IN EFI_PHYSICAL_ADDRESS Address
544 return (GetGuardedMemoryBits (Address
- EFI_PAGE_SIZE
, 2) == BIT0
);
548 Check to see if the page at the given address is guarded or not.
550 @param[in] Address The address to check for.
552 @return TRUE The page at Address is guarded.
553 @return FALSE The page at Address is not guarded.
558 IN EFI_PHYSICAL_ADDRESS Address
561 return (GetGuardMapBit (Address
) == 1);
565 Set the page at the given address to be a Guard page.
567 This is done by changing the page table attribute to be NOT PRSENT.
569 @param[in] BaseAddress Page address to Guard at
576 IN EFI_PHYSICAL_ADDRESS BaseAddress
580 // Set flag to make sure allocating memory without GUARD for page table
581 // operation; otherwise infinite loops could be caused.
585 // Note: This might overwrite other attributes needed by other features,
586 // such as memory protection (NX). Please make sure they are not enabled
589 gCpu
->SetMemoryAttributes (gCpu
, BaseAddress
, EFI_PAGE_SIZE
, EFI_MEMORY_RP
);
594 Unset the Guard page at the given address to the normal memory.
596 This is done by changing the page table attribute to be PRSENT.
598 @param[in] BaseAddress Page address to Guard at.
605 IN EFI_PHYSICAL_ADDRESS BaseAddress
609 // Set flag to make sure allocating memory without GUARD for page table
610 // operation; otherwise infinite loops could be caused.
614 // Note: This might overwrite other attributes needed by other features,
615 // such as memory protection (NX). Please make sure they are not enabled
618 gCpu
->SetMemoryAttributes (gCpu
, BaseAddress
, EFI_PAGE_SIZE
, 0);
623 Check to see if the memory at the given address should be guarded or not.
625 @param[in] MemoryType Memory type to check.
626 @param[in] AllocateType Allocation type to check.
627 @param[in] PageOrPool Indicate a page allocation or pool allocation.
630 @return TRUE The given type of memory should be guarded.
631 @return FALSE The given type of memory should not be guarded.
634 IsMemoryTypeToGuard (
635 IN EFI_MEMORY_TYPE MemoryType
,
636 IN EFI_ALLOCATE_TYPE AllocateType
,
644 if (gCpu
== NULL
|| AllocateType
== AllocateAddress
) {
649 if (gSmmBase2
!= NULL
) {
650 gSmmBase2
->InSmm (gSmmBase2
, &InSmm
);
657 if ((PcdGet8 (PcdHeapGuardPropertyMask
) & PageOrPool
) == 0) {
661 if (PageOrPool
== GUARD_HEAP_TYPE_POOL
) {
662 ConfigBit
= PcdGet64 (PcdHeapGuardPoolType
);
663 } else if (PageOrPool
== GUARD_HEAP_TYPE_PAGE
) {
664 ConfigBit
= PcdGet64 (PcdHeapGuardPageType
);
666 ConfigBit
= (UINT64
)-1;
669 if ((UINT32
)MemoryType
>= MEMORY_TYPE_OS_RESERVED_MIN
) {
671 } else if ((UINT32
) MemoryType
>= MEMORY_TYPE_OEM_RESERVED_MIN
) {
673 } else if (MemoryType
< EfiMaxMemoryType
) {
674 TestBit
= LShiftU64 (1, MemoryType
);
675 } else if (MemoryType
== EfiMaxMemoryType
) {
676 TestBit
= (UINT64
)-1;
681 return ((ConfigBit
& TestBit
) != 0);
685 Check to see if the pool at the given address should be guarded or not.
687 @param[in] MemoryType Pool type to check.
690 @return TRUE The given type of pool should be guarded.
691 @return FALSE The given type of pool should not be guarded.
695 IN EFI_MEMORY_TYPE MemoryType
698 return IsMemoryTypeToGuard (MemoryType
, AllocateAnyPages
,
699 GUARD_HEAP_TYPE_POOL
);
703 Check to see if the page at the given address should be guarded or not.
705 @param[in] MemoryType Page type to check.
706 @param[in] AllocateType Allocation type to check.
708 @return TRUE The given type of page should be guarded.
709 @return FALSE The given type of page should not be guarded.
713 IN EFI_MEMORY_TYPE MemoryType
,
714 IN EFI_ALLOCATE_TYPE AllocateType
717 return IsMemoryTypeToGuard (MemoryType
, AllocateType
, GUARD_HEAP_TYPE_PAGE
);
721 Set head Guard and tail Guard for the given memory range.
723 @param[in] Memory Base address of memory to set guard for.
724 @param[in] NumberOfPages Memory size in pages.
730 IN EFI_PHYSICAL_ADDRESS Memory
,
731 IN UINTN NumberOfPages
734 EFI_PHYSICAL_ADDRESS GuardPage
;
739 GuardPage
= Memory
+ EFI_PAGES_TO_SIZE (NumberOfPages
);
740 if (!IsGuardPage (GuardPage
)) {
741 SetGuardPage (GuardPage
);
745 GuardPage
= Memory
- EFI_PAGES_TO_SIZE (1);
746 if (!IsGuardPage (GuardPage
)) {
747 SetGuardPage (GuardPage
);
751 // Mark the memory range as Guarded
753 SetGuardedMemoryBits (Memory
, NumberOfPages
);
757 Unset head Guard and tail Guard for the given memory range.
759 @param[in] Memory Base address of memory to unset guard for.
760 @param[in] NumberOfPages Memory size in pages.
765 UnsetGuardForMemory (
766 IN EFI_PHYSICAL_ADDRESS Memory
,
767 IN UINTN NumberOfPages
770 EFI_PHYSICAL_ADDRESS GuardPage
;
773 if (NumberOfPages
== 0) {
778 // Head Guard must be one page before, if any.
781 // -------------------
782 // Head Guard -> 0 1 -> Don't free Head Guard (shared Guard)
783 // Head Guard -> 0 0 -> Free Head Guard either (not shared Guard)
784 // 1 X -> Don't free first page (need a new Guard)
785 // (it'll be turned into a Guard page later)
786 // -------------------
789 GuardPage
= Memory
- EFI_PAGES_TO_SIZE (1);
790 GuardBitmap
= GetGuardedMemoryBits (Memory
- EFI_PAGES_TO_SIZE (2), 2);
791 if ((GuardBitmap
& BIT1
) == 0) {
793 // Head Guard exists.
795 if ((GuardBitmap
& BIT0
) == 0) {
797 // If the head Guard is not a tail Guard of adjacent memory block,
800 UnsetGuardPage (GuardPage
);
804 // Pages before memory to free are still in Guard. It's a partial free
805 // case. Turn first page of memory block to free into a new Guard.
807 SetGuardPage (Memory
);
811 // Tail Guard must be the page after this memory block to free, if any.
814 // --------------------
815 // 1 0 <- Tail Guard -> Don't free Tail Guard (shared Guard)
816 // 0 0 <- Tail Guard -> Free Tail Guard either (not shared Guard)
817 // X 1 -> Don't free last page (need a new Guard)
818 // (it'll be turned into a Guard page later)
819 // --------------------
822 GuardPage
= Memory
+ EFI_PAGES_TO_SIZE (NumberOfPages
);
823 GuardBitmap
= GetGuardedMemoryBits (GuardPage
, 2);
824 if ((GuardBitmap
& BIT0
) == 0) {
826 // Tail Guard exists.
828 if ((GuardBitmap
& BIT1
) == 0) {
830 // If the tail Guard is not a head Guard of adjacent memory block,
831 // free it; otherwise, keep it.
833 UnsetGuardPage (GuardPage
);
837 // Pages after memory to free are still in Guard. It's a partial free
838 // case. We need to keep one page to be a head Guard.
840 SetGuardPage (GuardPage
- EFI_PAGES_TO_SIZE (1));
844 // No matter what, we just clear the mark of the Guarded memory.
846 ClearGuardedMemoryBits(Memory
, NumberOfPages
);
850 Adjust address of free memory according to existing and/or required Guard.
852 This function will check if there're existing Guard pages of adjacent
853 memory blocks, and try to use it as the Guard page of the memory to be
856 @param[in] Start Start address of free memory block.
857 @param[in] Size Size of free memory block.
858 @param[in] SizeRequested Size of memory to allocate.
860 @return The end address of memory block found.
861 @return 0 if no enough space for the required size of memory and its Guard.
867 IN UINT64 SizeRequested
872 Target
= Start
+ Size
- SizeRequested
;
875 // At least one more page needed for Guard page.
877 if (Size
< (SizeRequested
+ EFI_PAGES_TO_SIZE (1))) {
881 if (!IsGuardPage (Start
+ Size
)) {
882 // No Guard at tail to share. One more page is needed.
883 Target
-= EFI_PAGES_TO_SIZE (1);
887 if (Target
< Start
) {
892 if (Target
== Start
) {
893 if (!IsGuardPage (Target
- EFI_PAGES_TO_SIZE (1))) {
894 // No enough space for a new head Guard if no Guard at head to share.
899 // OK, we have enough pages for memory and its Guards. Return the End of the
901 return Target
+ SizeRequested
- 1;
905 Adjust the start address and number of pages to free according to Guard.
907 The purpose of this function is to keep the shared Guard page with adjacent
908 memory block if it's still in guard, or free it if no more sharing. Another
909 is to reserve pages as Guard pages in partial page free situation.
911 @param[in,out] Memory Base address of memory to free.
912 @param[in,out] NumberOfPages Size of memory to free.
918 IN OUT EFI_PHYSICAL_ADDRESS
*Memory
,
919 IN OUT UINTN
*NumberOfPages
922 EFI_PHYSICAL_ADDRESS Start
;
923 EFI_PHYSICAL_ADDRESS MemoryToTest
;
927 if (Memory
== NULL
|| NumberOfPages
== NULL
|| *NumberOfPages
== 0) {
932 PagesToFree
= *NumberOfPages
;
935 // Head Guard must be one page before, if any.
938 // -------------------
939 // Head Guard -> 0 1 -> Don't free Head Guard (shared Guard)
940 // Head Guard -> 0 0 -> Free Head Guard either (not shared Guard)
941 // 1 X -> Don't free first page (need a new Guard)
942 // (it'll be turned into a Guard page later)
943 // -------------------
946 MemoryToTest
= Start
- EFI_PAGES_TO_SIZE (2);
947 GuardBitmap
= GetGuardedMemoryBits (MemoryToTest
, 2);
948 if ((GuardBitmap
& BIT1
) == 0) {
950 // Head Guard exists.
952 if ((GuardBitmap
& BIT0
) == 0) {
954 // If the head Guard is not a tail Guard of adjacent memory block,
955 // free it; otherwise, keep it.
957 Start
-= EFI_PAGES_TO_SIZE (1);
962 // No Head Guard, and pages before memory to free are still in Guard. It's a
963 // partial free case. We need to keep one page to be a tail Guard.
965 Start
+= EFI_PAGES_TO_SIZE (1);
970 // Tail Guard must be the page after this memory block to free, if any.
973 // --------------------
974 // 1 0 <- Tail Guard -> Don't free Tail Guard (shared Guard)
975 // 0 0 <- Tail Guard -> Free Tail Guard either (not shared Guard)
976 // X 1 -> Don't free last page (need a new Guard)
977 // (it'll be turned into a Guard page later)
978 // --------------------
981 MemoryToTest
= Start
+ EFI_PAGES_TO_SIZE (PagesToFree
);
982 GuardBitmap
= GetGuardedMemoryBits (MemoryToTest
, 2);
983 if ((GuardBitmap
& BIT0
) == 0) {
985 // Tail Guard exists.
987 if ((GuardBitmap
& BIT1
) == 0) {
989 // If the tail Guard is not a head Guard of adjacent memory block,
990 // free it; otherwise, keep it.
994 } else if (PagesToFree
> 0) {
996 // No Tail Guard, and pages after memory to free are still in Guard. It's a
997 // partial free case. We need to keep one page to be a head Guard.
1003 *NumberOfPages
= PagesToFree
;
1007 Adjust the base and number of pages to really allocate according to Guard.
1009 @param[in,out] Memory Base address of free memory.
1010 @param[in,out] NumberOfPages Size of memory to allocate.
1016 IN OUT EFI_PHYSICAL_ADDRESS
*Memory
,
1017 IN OUT UINTN
*NumberOfPages
1021 // FindFreePages() has already taken the Guard into account. It's safe to
1022 // adjust the start address and/or number of pages here, to make sure that
1023 // the Guards are also "allocated".
1025 if (!IsGuardPage (*Memory
+ EFI_PAGES_TO_SIZE (*NumberOfPages
))) {
1026 // No tail Guard, add one.
1027 *NumberOfPages
+= 1;
1030 if (!IsGuardPage (*Memory
- EFI_PAGE_SIZE
)) {
1031 // No head Guard, add one.
1032 *Memory
-= EFI_PAGE_SIZE
;
1033 *NumberOfPages
+= 1;
1038 Adjust the pool head position to make sure the Guard page is adjavent to
1039 pool tail or pool head.
1041 @param[in] Memory Base address of memory allocated.
1042 @param[in] NoPages Number of pages actually allocated.
1043 @param[in] Size Size of memory requested.
1044 (plus pool head/tail overhead)
1046 @return Address of pool head.
1050 IN EFI_PHYSICAL_ADDRESS Memory
,
1055 if ((PcdGet8 (PcdHeapGuardPropertyMask
) & BIT7
) != 0) {
1057 // Pool head is put near the head Guard
1059 return (VOID
*)(UINTN
)Memory
;
1063 // Pool head is put near the tail Guard
1065 return (VOID
*)(UINTN
)(Memory
+ EFI_PAGES_TO_SIZE (NoPages
) - Size
);
1069 Get the page base address according to pool head address.
1071 @param[in] Memory Head address of pool to free.
1073 @return Address of pool head.
1077 IN EFI_PHYSICAL_ADDRESS Memory
1080 if ((PcdGet8 (PcdHeapGuardPropertyMask
) & BIT7
) != 0) {
1082 // Pool head is put near the head Guard
1084 return (VOID
*)(UINTN
)Memory
;
1088 // Pool head is put near the tail Guard
1090 return (VOID
*)(UINTN
)(Memory
& ~EFI_PAGE_MASK
);
1094 Allocate or free guarded memory.
1096 @param[in] Start Start address of memory to allocate or free.
1097 @param[in] NumberOfPages Memory size in pages.
1098 @param[in] NewType Memory type to convert to.
1103 CoreConvertPagesWithGuard (
1105 IN UINTN NumberOfPages
,
1106 IN EFI_MEMORY_TYPE NewType
1109 if (NewType
== EfiConventionalMemory
) {
1110 AdjustMemoryF (&Start
, &NumberOfPages
);
1111 if (NumberOfPages
== 0) {
1115 AdjustMemoryA (&Start
, &NumberOfPages
);
1118 return CoreConvertPages (Start
, NumberOfPages
, NewType
);
1122 Helper function to convert a UINT64 value in binary to a string.
1124 @param[in] Value Value of a UINT64 integer.
1125 @param[out] BinString String buffer to contain the conversion result.
1132 OUT CHAR8
*BinString
1137 if (BinString
== NULL
) {
1141 for (Index
= 64; Index
> 0; --Index
) {
1142 BinString
[Index
- 1] = '0' + (Value
& 1);
1143 Value
= RShiftU64 (Value
, 1);
1145 BinString
[64] = '\0';
1149 Dump the guarded memory bit map.
1153 DumpGuardedMemoryBitmap (
1157 UINTN Entries
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1158 UINTN Shifts
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1159 UINTN Indices
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1160 UINT64 Tables
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1161 UINT64 Addresses
[GUARDED_HEAP_MAP_TABLE_DEPTH
];
1166 CHAR8 String
[GUARDED_HEAP_MAP_ENTRY_BITS
+ 1];
1170 if (mGuardedMemoryMap
== 0 ||
1172 mMapLevel
> GUARDED_HEAP_MAP_TABLE_DEPTH
) {
1176 Ruler1
= " 3 2 1 0";
1177 Ruler2
= "FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210";
1179 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, "============================="
1180 " Guarded Memory Bitmap "
1181 "==============================\r\n"));
1182 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, " %a\r\n", Ruler1
));
1183 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, " %a\r\n", Ruler2
));
1185 CopyMem (Entries
, mLevelMask
, sizeof (Entries
));
1186 CopyMem (Shifts
, mLevelShift
, sizeof (Shifts
));
1188 SetMem (Indices
, sizeof(Indices
), 0);
1189 SetMem (Tables
, sizeof(Tables
), 0);
1190 SetMem (Addresses
, sizeof(Addresses
), 0);
1192 Level
= GUARDED_HEAP_MAP_TABLE_DEPTH
- mMapLevel
;
1193 Tables
[Level
] = mGuardedMemoryMap
;
1198 if (Indices
[Level
] > Entries
[Level
]) {
1205 HEAP_GUARD_DEBUG_LEVEL
,
1206 "========================================="
1207 "=========================================\r\n"
1212 TableEntry
= ((UINT64
*)(UINTN
)Tables
[Level
])[Indices
[Level
]];
1213 Address
= Addresses
[Level
];
1215 if (TableEntry
== 0) {
1217 if (Level
== GUARDED_HEAP_MAP_TABLE_DEPTH
- 1) {
1218 if (RepeatZero
== 0) {
1219 Uint64ToBinString(TableEntry
, String
);
1220 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, "%016lx: %a\r\n", Address
, String
));
1221 } else if (RepeatZero
== 1) {
1222 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, "... : ...\r\n"));
1227 } else if (Level
< GUARDED_HEAP_MAP_TABLE_DEPTH
- 1) {
1230 Tables
[Level
] = TableEntry
;
1231 Addresses
[Level
] = Address
;
1240 Uint64ToBinString(TableEntry
, String
);
1241 DEBUG ((HEAP_GUARD_DEBUG_LEVEL
, "%016lx: %a\r\n", Address
, String
));
1246 if (Level
< (GUARDED_HEAP_MAP_TABLE_DEPTH
- (INTN
)mMapLevel
)) {
1250 Indices
[Level
] += 1;
1251 Address
= (Level
== 0) ? 0 : Addresses
[Level
- 1];
1252 Addresses
[Level
] = Address
| LShiftU64(Indices
[Level
], Shifts
[Level
]);