2 Data type, macros and function prototypes of heap guard feature.
4 Copyright (c) 2017-2018, Intel Corporation. All rights reserved.<BR>
5 SPDX-License-Identifier: BSD-2-Clause-Patent
13 // Following macros are used to define and access the guarded memory bitmap
16 // To simplify the access and reduce the memory used for this table, the
17 // table is constructed in the similar way as page table structure but in
18 // reverse direction, i.e. from bottom growing up to top.
20 // - 1-bit tracks 1 page (4KB)
21 // - 1-UINT64 map entry tracks 256KB memory
22 // - 1K-UINT64 map table tracks 256MB memory
23 // - Five levels of tables can track any address of memory of 64-bit
24 // system, like below.
26 // 512 * 512 * 512 * 512 * 1K * 64b * 4K
27 // 111111111 111111111 111111111 111111111 1111111111 111111 111111111111
28 // 63 54 45 36 27 17 11 0
29 // 9b 9b 9b 9b 10b 6b 12b
30 // L0 -> L1 -> L2 -> L3 -> L4 -> bits -> page
31 // 1FF 1FF 1FF 1FF 3FF 3F FFF
33 // L4 table has 1K * sizeof(UINT64) = 8K (2-page), which can track 256MB
34 // memory. Each table of L0-L3 will be allocated when its memory address
35 // range is to be tracked. Only 1-page will be allocated each time. This
36 // can save memories used to establish this map table.
38 // For a normal configuration of system with 4G memory, two levels of tables
39 // can track the whole memory, because two levels (L3+L4) of map tables have
40 // already coverred 37-bit of memory address. And for a normal UEFI BIOS,
41 // less than 128M memory would be consumed during boot. That means we just
44 // 1-page (L3) + 2-page (L4)
46 // memory (3 pages) to track the memory allocation works. In this case,
47 // there's no need to setup L0-L2 tables.
51 // Each entry occupies 8B/64b. 1-page can hold 512 entries, which spans 9
52 // bits in address. (512 = 1 << 9)
54 #define BYTE_LENGTH_SHIFT 3 // (8 = 1 << 3)
56 #define GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT \
57 (EFI_PAGE_SHIFT - BYTE_LENGTH_SHIFT)
59 #define GUARDED_HEAP_MAP_TABLE_DEPTH 5
61 // Use UINT64_index + bit_index_of_UINT64 to locate the bit in may
62 #define GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT 6 // (64 = 1 << 6)
64 #define GUARDED_HEAP_MAP_ENTRY_BITS \
65 (1 << GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)
67 #define GUARDED_HEAP_MAP_ENTRY_BYTES \
68 (GUARDED_HEAP_MAP_ENTRY_BITS / 8)
70 // L4 table address width: 64 - 9 * 4 - 6 - 12 = 10b
71 #define GUARDED_HEAP_MAP_ENTRY_SHIFT \
72 (GUARDED_HEAP_MAP_ENTRY_BITS \
73 - GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 4 \
74 - GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT \
77 // L4 table address mask: (1 << 10 - 1) = 0x3FF
78 #define GUARDED_HEAP_MAP_ENTRY_MASK \
79 ((1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) - 1)
81 // Size of each L4 table: (1 << 10) * 8 = 8KB = 2-page
82 #define GUARDED_HEAP_MAP_SIZE \
83 ((1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) * GUARDED_HEAP_MAP_ENTRY_BYTES)
85 // Memory size tracked by one L4 table: 8KB * 8 * 4KB = 256MB
86 #define GUARDED_HEAP_MAP_UNIT_SIZE \
87 (GUARDED_HEAP_MAP_SIZE * 8 * EFI_PAGE_SIZE)
89 // L4 table entry number: 8KB / 8 = 1024
90 #define GUARDED_HEAP_MAP_ENTRIES_PER_UNIT \
91 (GUARDED_HEAP_MAP_SIZE / GUARDED_HEAP_MAP_ENTRY_BYTES)
93 // L4 table entry indexing
94 #define GUARDED_HEAP_MAP_ENTRY_INDEX(Address) \
95 (RShiftU64 (Address, EFI_PAGE_SHIFT \
96 + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT) \
97 & GUARDED_HEAP_MAP_ENTRY_MASK)
99 // L4 table entry bit indexing
100 #define GUARDED_HEAP_MAP_ENTRY_BIT_INDEX(Address) \
101 (RShiftU64 (Address, EFI_PAGE_SHIFT) \
102 & ((1 << GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT) - 1))
105 // Total bits (pages) tracked by one L4 table (65536-bit)
107 #define GUARDED_HEAP_MAP_BITS \
108 (1 << (GUARDED_HEAP_MAP_ENTRY_SHIFT \
109 + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT))
112 // Bit indexing inside the whole L4 table (0 - 65535)
114 #define GUARDED_HEAP_MAP_BIT_INDEX(Address) \
115 (RShiftU64 (Address, EFI_PAGE_SHIFT) \
116 & ((1 << (GUARDED_HEAP_MAP_ENTRY_SHIFT \
117 + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)) - 1))
120 // Memory address bit width tracked by L4 table: 10 + 6 + 12 = 28
122 #define GUARDED_HEAP_MAP_TABLE_SHIFT \
123 (GUARDED_HEAP_MAP_ENTRY_SHIFT + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT \
127 // Macro used to initialize the local array variable for map table traversing
128 // {55, 46, 37, 28, 18}
130 #define GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS \
132 GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 3, \
133 GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 2, \
134 GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT, \
135 GUARDED_HEAP_MAP_TABLE_SHIFT, \
136 EFI_PAGE_SHIFT + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT \
140 // Masks used to extract address range of each level of table
141 // {0x1FF, 0x1FF, 0x1FF, 0x1FF, 0x3FF}
143 #define GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS \
145 (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1, \
146 (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1, \
147 (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1, \
148 (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1, \
149 (1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) - 1 \
153 // Memory type to guard (matching the related PCD definition)
155 #define GUARD_HEAP_TYPE_PAGE BIT0
156 #define GUARD_HEAP_TYPE_POOL BIT1
157 #define GUARD_HEAP_TYPE_FREED BIT4
158 #define GUARD_HEAP_TYPE_ALL \
159 (GUARD_HEAP_TYPE_PAGE|GUARD_HEAP_TYPE_POOL|GUARD_HEAP_TYPE_FREED)
162 // Debug message level
164 #define HEAP_GUARD_DEBUG_LEVEL (DEBUG_POOL|DEBUG_PAGE)
169 EFI_PHYSICAL_ADDRESS Address
;
174 Internal function. Converts a memory range to the specified type.
175 The range must exist in the memory map.
177 @param Start The first address of the range Must be page
179 @param NumberOfPages The number of pages to convert.
180 @param NewType The new type for the memory range.
182 @retval EFI_INVALID_PARAMETER Invalid parameter.
183 @retval EFI_NOT_FOUND Could not find a descriptor cover the specified
184 range or convertion not allowed.
185 @retval EFI_SUCCESS Successfully converts the memory range to the
192 IN UINT64 NumberOfPages
,
193 IN EFI_MEMORY_TYPE NewType
197 Allocate or free guarded memory.
199 @param[in] Start Start address of memory to allocate or free.
200 @param[in] NumberOfPages Memory size in pages.
201 @param[in] NewType Memory type to convert to.
206 CoreConvertPagesWithGuard (
208 IN UINTN NumberOfPages
,
209 IN EFI_MEMORY_TYPE NewType
213 Set head Guard and tail Guard for the given memory range.
215 @param[in] Memory Base address of memory to set guard for.
216 @param[in] NumberOfPages Memory size in pages.
222 IN EFI_PHYSICAL_ADDRESS Memory
,
223 IN UINTN NumberOfPages
227 Unset head Guard and tail Guard for the given memory range.
229 @param[in] Memory Base address of memory to unset guard for.
230 @param[in] NumberOfPages Memory size in pages.
235 UnsetGuardForMemory (
236 IN EFI_PHYSICAL_ADDRESS Memory
,
237 IN UINTN NumberOfPages
241 Adjust the base and number of pages to really allocate according to Guard.
243 @param[in,out] Memory Base address of free memory.
244 @param[in,out] NumberOfPages Size of memory to allocate.
250 IN OUT EFI_PHYSICAL_ADDRESS
*Memory
,
251 IN OUT UINTN
*NumberOfPages
255 Adjust the start address and number of pages to free according to Guard.
257 The purpose of this function is to keep the shared Guard page with adjacent
258 memory block if it's still in guard, or free it if no more sharing. Another
259 is to reserve pages as Guard pages in partial page free situation.
261 @param[in,out] Memory Base address of memory to free.
262 @param[in,out] NumberOfPages Size of memory to free.
268 IN OUT EFI_PHYSICAL_ADDRESS
*Memory
,
269 IN OUT UINTN
*NumberOfPages
273 Adjust address of free memory according to existing and/or required Guard.
275 This function will check if there're existing Guard pages of adjacent
276 memory blocks, and try to use it as the Guard page of the memory to be
279 @param[in] Start Start address of free memory block.
280 @param[in] Size Size of free memory block.
281 @param[in] SizeRequested Size of memory to allocate.
283 @return The end address of memory block found.
284 @return 0 if no enough space for the required size of memory and its Guard.
290 IN UINT64 SizeRequested
294 Check to see if the pool at the given address should be guarded or not.
296 @param[in] MemoryType Pool type to check.
299 @return TRUE The given type of pool should be guarded.
300 @return FALSE The given type of pool should not be guarded.
304 IN EFI_MEMORY_TYPE MemoryType
308 Check to see if the page at the given address should be guarded or not.
310 @param[in] MemoryType Page type to check.
311 @param[in] AllocateType Allocation type to check.
313 @return TRUE The given type of page should be guarded.
314 @return FALSE The given type of page should not be guarded.
318 IN EFI_MEMORY_TYPE MemoryType
,
319 IN EFI_ALLOCATE_TYPE AllocateType
323 Check to see if the page at the given address is guarded or not.
325 @param[in] Address The address to check for.
327 @return TRUE The page at Address is guarded.
328 @return FALSE The page at Address is not guarded.
333 IN EFI_PHYSICAL_ADDRESS Address
337 Check to see if the page at the given address is a Guard page or not.
339 @param[in] Address The address to check for.
341 @return TRUE The page at Address is a Guard page.
342 @return FALSE The page at Address is not a Guard page.
347 IN EFI_PHYSICAL_ADDRESS Address
351 Dump the guarded memory bit map.
355 DumpGuardedMemoryBitmap (
360 Adjust the pool head position to make sure the Guard page is adjavent to
361 pool tail or pool head.
363 @param[in] Memory Base address of memory allocated.
364 @param[in] NoPages Number of pages actually allocated.
365 @param[in] Size Size of memory requested.
366 (plus pool head/tail overhead)
368 @return Address of pool head.
372 IN EFI_PHYSICAL_ADDRESS Memory
,
378 Get the page base address according to pool head address.
380 @param[in] Memory Head address of pool to free.
382 @return Address of pool head.
386 IN EFI_PHYSICAL_ADDRESS Memory
390 Check to see if the heap guard is enabled for page and/or pool allocation.
392 @param[in] GuardType Specify the sub-type(s) of Heap Guard.
402 Notify function used to set all Guard pages after CPU Arch Protocol installed.
405 HeapGuardCpuArchProtocolNotify (
410 This function checks to see if the given memory map descriptor in a memory map
411 can be merged with any guarded free pages.
413 @param MemoryMapEntry A pointer to a descriptor in MemoryMap.
414 @param MaxAddress Maximum address to stop the merge.
421 IN EFI_MEMORY_DESCRIPTOR
*MemoryMapEntry
,
422 IN EFI_PHYSICAL_ADDRESS MaxAddress
426 Record freed pages as well as mark them as not-present, if enabled.
428 @param[in] BaseAddress Base address of just freed pages.
429 @param[in] Pages Number of freed pages.
435 GuardFreedPagesChecked (
436 IN EFI_PHYSICAL_ADDRESS BaseAddress
,
441 Put part (at most 64 pages a time) guarded free pages back to free page pool.
443 Freed memory guard is used to detect Use-After-Free (UAF) memory issue, which
444 makes use of 'Used then throw away' way to detect any illegal access to freed
445 memory. The thrown-away memory will be marked as not-present so that any access
446 to those memory (after free) will be caught by page-fault exception.
448 The problem is that this will consume lots of memory space. Once no memory
449 left in pool to allocate, we have to restore part of the freed pages to their
450 normal function. Otherwise the whole system will stop functioning.
452 @param StartAddress Start address of promoted memory.
453 @param EndAddress End address of promoted memory.
455 @return TRUE Succeeded to promote memory.
456 @return FALSE No free memory found.
460 PromoteGuardedFreePages (
461 OUT EFI_PHYSICAL_ADDRESS
*StartAddress
,
462 OUT EFI_PHYSICAL_ADDRESS
*EndAddress
465 extern BOOLEAN mOnGuarding
;