1 //===-- asan_mapping.h ------------------------------------------*- C++ -*-===//
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
6 //===----------------------------------------------------------------------===//
8 // This file is a part of AddressSanitizer, an address sanity checker.
10 // Defines ASan memory mapping.
11 //===----------------------------------------------------------------------===//
12 #ifndef ASAN_MAPPING_H
13 #define ASAN_MAPPING_H
15 #include "asan_internal.h"
17 // The full explanation of the memory mapping could be found here:
18 // http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
20 #if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1
21 extern __attribute__((visibility("default"))) uptr __asan_mapping_scale
;
22 extern __attribute__((visibility("default"))) uptr __asan_mapping_offset
;
23 # define SHADOW_SCALE (__asan_mapping_scale)
24 # define SHADOW_OFFSET (__asan_mapping_offset)
27 # define SHADOW_SCALE (3)
28 # define SHADOW_OFFSET (0)
30 # define SHADOW_SCALE (3)
31 # if SANITIZER_WORDSIZE == 32
32 # define SHADOW_OFFSET (1 << 29)
34 # if defined(__powerpc64__)
35 # define SHADOW_OFFSET (1ULL << 41)
37 # define SHADOW_OFFSET (1ULL << 44)
41 #endif // ASAN_FLEXIBLE_MAPPING_AND_OFFSET
43 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
44 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) | (SHADOW_OFFSET))
45 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
47 #if SANITIZER_WORDSIZE == 64
48 # if defined(__powerpc64__)
49 static const uptr kHighMemEnd
= 0x00000fffffffffffUL
;
51 static const uptr kHighMemEnd
= 0x00007fffffffffffUL
;
53 #else // SANITIZER_WORDSIZE == 32
54 static const uptr kHighMemEnd
= 0xffffffff;
55 #endif // SANITIZER_WORDSIZE
59 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
61 #define kLowShadowBeg SHADOW_OFFSET
62 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
64 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
66 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
67 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
69 // With the zero shadow base we can not actually map pages starting from 0.
70 // This constant is somewhat arbitrary.
71 #define kZeroBaseShadowStart (1 << 18)
73 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
74 : kZeroBaseShadowStart)
75 #define kShadowGapEnd (kHighShadowBeg - 1)
77 #define kGlobalAndStackRedzone \
78 (SHADOW_GRANULARITY < 32 ? 32 : SHADOW_GRANULARITY)
82 static inline bool AddrIsInLowMem(uptr a
) {
83 return a
< kLowMemEnd
;
86 static inline bool AddrIsInLowShadow(uptr a
) {
87 return a
>= kLowShadowBeg
&& a
<= kLowShadowEnd
;
90 static inline bool AddrIsInHighMem(uptr a
) {
91 return a
>= kHighMemBeg
&& a
<= kHighMemEnd
;
94 static inline bool AddrIsInMem(uptr a
) {
95 return AddrIsInLowMem(a
) || AddrIsInHighMem(a
);
98 static inline uptr
MemToShadow(uptr p
) {
99 CHECK(AddrIsInMem(p
));
100 return MEM_TO_SHADOW(p
);
103 static inline bool AddrIsInHighShadow(uptr a
) {
104 return a
>= kHighShadowBeg
&& a
<= kHighMemEnd
;
107 static inline bool AddrIsInShadow(uptr a
) {
108 return AddrIsInLowShadow(a
) || AddrIsInHighShadow(a
);
111 static inline bool AddrIsInShadowGap(uptr a
) {
112 return a
>= kShadowGapBeg
&& a
<= kShadowGapEnd
;
115 static inline bool AddrIsAlignedByGranularity(uptr a
) {
116 return (a
& (SHADOW_GRANULARITY
- 1)) == 0;
119 static inline bool AddressIsPoisoned(uptr a
) {
120 const uptr kAccessSize
= 1;
121 u8
*shadow_address
= (u8
*)MemToShadow(a
);
122 s8 shadow_value
= *shadow_address
;
124 u8 last_accessed_byte
= (a
& (SHADOW_GRANULARITY
- 1))
126 return (last_accessed_byte
>= shadow_value
);
131 } // namespace __asan
133 #endif // ASAN_MAPPING_H