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 // Typical shadow mapping on Linux/x86_64 with SHADOW_OFFSET == 0x00007fff8000:
21 // || `[0x10007fff8000, 0x7fffffffffff]` || HighMem ||
22 // || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
23 // || `[0x00008fff7000, 0x02008fff6fff]` || ShadowGap ||
24 // || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow ||
25 // || `[0x000000000000, 0x00007fff7fff]` || LowMem ||
27 // When SHADOW_OFFSET is zero (-pie):
28 // || `[0x100000000000, 0x7fffffffffff]` || HighMem ||
29 // || `[0x020000000000, 0x0fffffffffff]` || HighShadow ||
30 // || `[0x000000040000, 0x01ffffffffff]` || ShadowGap ||
32 // Special case when something is already mapped between
33 // 0x003000000000 and 0x005000000000 (e.g. when prelink is installed):
34 // || `[0x10007fff8000, 0x7fffffffffff]` || HighMem ||
35 // || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
36 // || `[0x005000000000, 0x02008fff6fff]` || ShadowGap3 ||
37 // || `[0x003000000000, 0x004fffffffff]` || MidMem ||
38 // || `[0x000a7fff8000, 0x002fffffffff]` || ShadowGap2 ||
39 // || `[0x00067fff8000, 0x000a7fff7fff]` || MidShadow ||
40 // || `[0x00008fff7000, 0x00067fff7fff]` || ShadowGap ||
41 // || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow ||
42 // || `[0x000000000000, 0x00007fff7fff]` || LowMem ||
44 // Default Linux/i386 mapping:
45 // || `[0x40000000, 0xffffffff]` || HighMem ||
46 // || `[0x28000000, 0x3fffffff]` || HighShadow ||
47 // || `[0x24000000, 0x27ffffff]` || ShadowGap ||
48 // || `[0x20000000, 0x23ffffff]` || LowShadow ||
49 // || `[0x00000000, 0x1fffffff]` || LowMem ||
51 // Default Linux/MIPS mapping:
52 // || `[0x2aaa8000, 0xffffffff]` || HighMem ||
53 // || `[0x0fffd000, 0x2aaa7fff]` || HighShadow ||
54 // || `[0x0bffd000, 0x0fffcfff]` || ShadowGap ||
55 // || `[0x0aaa8000, 0x0bffcfff]` || LowShadow ||
56 // || `[0x00000000, 0x0aaa7fff]` || LowMem ||
58 static const u64 kDefaultShadowScale
= 3;
59 static const u64 kDefaultShadowOffset32
= 1ULL << 29;
60 static const u64 kDefaultShadowOffset64
= 1ULL << 44;
61 static const u64 kDefaultShort64bitShadowOffset
= 0x7FFF8000; // < 2G.
62 static const u64 kPPC64_ShadowOffset64
= 1ULL << 41;
63 static const u64 kMIPS32_ShadowOffset32
= 0x0aaa8000;
65 #if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1
66 extern "C" SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_scale
;
67 extern "C" SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_offset
;
68 # define SHADOW_SCALE (__asan_mapping_scale)
69 # define SHADOW_OFFSET (__asan_mapping_offset)
71 # define SHADOW_SCALE kDefaultShadowScale
72 # if SANITIZER_ANDROID
73 # define SHADOW_OFFSET (0)
75 # if SANITIZER_WORDSIZE == 32
76 # if defined(__mips__)
77 # define SHADOW_OFFSET kMIPS32_ShadowOffset32
79 # define SHADOW_OFFSET kDefaultShadowOffset32
82 # if defined(__powerpc64__)
83 # define SHADOW_OFFSET kPPC64_ShadowOffset64
85 # define SHADOW_OFFSET kDefaultShadowOffset64
87 # define SHADOW_OFFSET kDefaultShort64bitShadowOffset
91 #endif // ASAN_FLEXIBLE_MAPPING_AND_OFFSET
93 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
94 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
95 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
98 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
100 #define kLowShadowBeg SHADOW_OFFSET
101 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
103 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
105 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
106 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
108 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
109 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
111 // With the zero shadow base we can not actually map pages starting from 0.
112 // This constant is somewhat arbitrary.
113 #define kZeroBaseShadowStart (1 << 18)
115 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
116 : kZeroBaseShadowStart)
117 #define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
119 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
120 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
122 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
123 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
125 #define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below.
127 #if DO_ASAN_MAPPING_PROFILE
128 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
130 # define PROFILE_ASAN_MAPPING()
133 // If 1, all shadow boundaries are constants.
134 // Don't set to 1 other than for testing.
135 #define ASAN_FIXED_MAPPING 0
139 extern uptr AsanMappingProfile
[];
141 #if ASAN_FIXED_MAPPING
142 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison
143 // with non-fixed mapping. As of r175253 (Feb 2013) the performance
144 // difference between fixed and non-fixed mapping is below the noise level.
145 static uptr kHighMemEnd
= 0x7fffffffffffULL
;
146 static uptr kMidMemBeg
= 0x3000000000ULL
;
147 static uptr kMidMemEnd
= 0x4fffffffffULL
;
149 extern uptr kHighMemEnd
, kMidMemBeg
, kMidMemEnd
; // Initialized in __asan_init.
152 static inline bool AddrIsInLowMem(uptr a
) {
153 PROFILE_ASAN_MAPPING();
154 return a
< kLowMemEnd
;
157 static inline bool AddrIsInLowShadow(uptr a
) {
158 PROFILE_ASAN_MAPPING();
159 return a
>= kLowShadowBeg
&& a
<= kLowShadowEnd
;
162 static inline bool AddrIsInHighMem(uptr a
) {
163 PROFILE_ASAN_MAPPING();
164 return a
>= kHighMemBeg
&& a
<= kHighMemEnd
;
167 static inline bool AddrIsInMidMem(uptr a
) {
168 PROFILE_ASAN_MAPPING();
169 return kMidMemBeg
&& a
>= kMidMemBeg
&& a
<= kMidMemEnd
;
172 static inline bool AddrIsInMem(uptr a
) {
173 PROFILE_ASAN_MAPPING();
174 return AddrIsInLowMem(a
) || AddrIsInMidMem(a
) || AddrIsInHighMem(a
);
177 static inline uptr
MemToShadow(uptr p
) {
178 PROFILE_ASAN_MAPPING();
179 CHECK(AddrIsInMem(p
));
180 return MEM_TO_SHADOW(p
);
183 static inline bool AddrIsInHighShadow(uptr a
) {
184 PROFILE_ASAN_MAPPING();
185 return a
>= kHighShadowBeg
&& a
<= kHighMemEnd
;
188 static inline bool AddrIsInMidShadow(uptr a
) {
189 PROFILE_ASAN_MAPPING();
190 return kMidMemBeg
&& a
>= kMidShadowBeg
&& a
<= kMidMemEnd
;
193 static inline bool AddrIsInShadow(uptr a
) {
194 PROFILE_ASAN_MAPPING();
195 return AddrIsInLowShadow(a
) || AddrIsInMidShadow(a
) || AddrIsInHighShadow(a
);
198 static inline bool AddrIsInShadowGap(uptr a
) {
199 PROFILE_ASAN_MAPPING();
201 if (a
<= kShadowGapEnd
)
202 return SHADOW_OFFSET
== 0 || a
>= kShadowGapBeg
;
203 return (a
>= kShadowGap2Beg
&& a
<= kShadowGap2End
) ||
204 (a
>= kShadowGap3Beg
&& a
<= kShadowGap3End
);
206 // In zero-based shadow mode we treat addresses near zero as addresses
207 // in shadow gap as well.
208 if (SHADOW_OFFSET
== 0)
209 return a
<= kShadowGapEnd
;
210 return a
>= kShadowGapBeg
&& a
<= kShadowGapEnd
;
213 static inline bool AddrIsAlignedByGranularity(uptr a
) {
214 PROFILE_ASAN_MAPPING();
215 return (a
& (SHADOW_GRANULARITY
- 1)) == 0;
218 static inline bool AddressIsPoisoned(uptr a
) {
219 PROFILE_ASAN_MAPPING();
220 const uptr kAccessSize
= 1;
221 u8
*shadow_address
= (u8
*)MEM_TO_SHADOW(a
);
222 s8 shadow_value
= *shadow_address
;
224 u8 last_accessed_byte
= (a
& (SHADOW_GRANULARITY
- 1))
226 return (last_accessed_byte
>= shadow_value
);
231 // Must be after all calls to PROFILE_ASAN_MAPPING().
232 static const uptr kAsanMappingProfileSize
= __LINE__
;
234 } // namespace __asan
236 #endif // ASAN_MAPPING_H