1 //===-- asan_mapping.h ------------------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file is a part of AddressSanitizer, an address sanity checker.
12 // Defines ASan memory mapping.
13 //===----------------------------------------------------------------------===//
14 #ifndef ASAN_MAPPING_H
15 #define ASAN_MAPPING_H
17 #include "asan_internal.h"
19 // The full explanation of the memory mapping could be found here:
20 // http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
22 // Typical shadow mapping on Linux/x86_64 with SHADOW_OFFSET == 0x00007fff8000:
23 // || `[0x10007fff8000, 0x7fffffffffff]` || HighMem ||
24 // || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
25 // || `[0x00008fff7000, 0x02008fff6fff]` || ShadowGap ||
26 // || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow ||
27 // || `[0x000000000000, 0x00007fff7fff]` || LowMem ||
29 // When SHADOW_OFFSET is zero (-pie):
30 // || `[0x100000000000, 0x7fffffffffff]` || HighMem ||
31 // || `[0x020000000000, 0x0fffffffffff]` || HighShadow ||
32 // || `[0x000000040000, 0x01ffffffffff]` || ShadowGap ||
34 // Special case when something is already mapped between
35 // 0x003000000000 and 0x005000000000 (e.g. when prelink is installed):
36 // || `[0x10007fff8000, 0x7fffffffffff]` || HighMem ||
37 // || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
38 // || `[0x005000000000, 0x02008fff6fff]` || ShadowGap3 ||
39 // || `[0x003000000000, 0x004fffffffff]` || MidMem ||
40 // || `[0x000a7fff8000, 0x002fffffffff]` || ShadowGap2 ||
41 // || `[0x00067fff8000, 0x000a7fff7fff]` || MidShadow ||
42 // || `[0x00008fff7000, 0x00067fff7fff]` || ShadowGap ||
43 // || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow ||
44 // || `[0x000000000000, 0x00007fff7fff]` || LowMem ||
46 // Default Linux/i386 mapping:
47 // || `[0x40000000, 0xffffffff]` || HighMem ||
48 // || `[0x28000000, 0x3fffffff]` || HighShadow ||
49 // || `[0x24000000, 0x27ffffff]` || ShadowGap ||
50 // || `[0x20000000, 0x23ffffff]` || LowShadow ||
51 // || `[0x00000000, 0x1fffffff]` || LowMem ||
53 // Default Linux/MIPS mapping:
54 // || `[0x2aaa8000, 0xffffffff]` || HighMem ||
55 // || `[0x0fffd000, 0x2aaa7fff]` || HighShadow ||
56 // || `[0x0bffd000, 0x0fffcfff]` || ShadowGap ||
57 // || `[0x0aaa8000, 0x0bffcfff]` || LowShadow ||
58 // || `[0x00000000, 0x0aaa7fff]` || LowMem ||
60 static const u64 kDefaultShadowScale
= 3;
61 static const u64 kDefaultShadowOffset32
= 1ULL << 29;
62 static const u64 kDefaultShadowOffset64
= 1ULL << 44;
63 static const u64 kDefaultShort64bitShadowOffset
= 0x7FFF8000; // < 2G.
64 static const u64 kPPC64_ShadowOffset64
= 1ULL << 41;
65 static const u64 kMIPS32_ShadowOffset32
= 0x0aaa8000;
67 #if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1
68 extern "C" SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_scale
;
69 extern "C" SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_offset
;
70 # define SHADOW_SCALE (__asan_mapping_scale)
71 # define SHADOW_OFFSET (__asan_mapping_offset)
73 # define SHADOW_SCALE kDefaultShadowScale
74 # if SANITIZER_ANDROID
75 # define SHADOW_OFFSET (0)
77 # if SANITIZER_WORDSIZE == 32
78 # if defined(__mips__)
79 # define SHADOW_OFFSET kMIPS32_ShadowOffset32
81 # define SHADOW_OFFSET kDefaultShadowOffset32
84 # if defined(__powerpc64__)
85 # define SHADOW_OFFSET kPPC64_ShadowOffset64
87 # define SHADOW_OFFSET kDefaultShadowOffset64
89 # define SHADOW_OFFSET kDefaultShort64bitShadowOffset
93 #endif // ASAN_FLEXIBLE_MAPPING_AND_OFFSET
95 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
96 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
97 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
100 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
102 #define kLowShadowBeg SHADOW_OFFSET
103 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
105 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
107 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
108 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
110 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
111 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
113 // With the zero shadow base we can not actually map pages starting from 0.
114 // This constant is somewhat arbitrary.
115 #define kZeroBaseShadowStart (1 << 18)
117 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
118 : kZeroBaseShadowStart)
119 #define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
121 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
122 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
124 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
125 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
127 #define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below.
129 #if DO_ASAN_MAPPING_PROFILE
130 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
132 # define PROFILE_ASAN_MAPPING()
135 // If 1, all shadow boundaries are constants.
136 // Don't set to 1 other than for testing.
137 #define ASAN_FIXED_MAPPING 0
141 extern uptr AsanMappingProfile
[];
143 #if ASAN_FIXED_MAPPING
144 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison
145 // with non-fixed mapping. As of r175253 (Feb 2013) the performance
146 // difference between fixed and non-fixed mapping is below the noise level.
147 static uptr kHighMemEnd
= 0x7fffffffffffULL
;
148 static uptr kMidMemBeg
= 0x3000000000ULL
;
149 static uptr kMidMemEnd
= 0x4fffffffffULL
;
151 extern uptr kHighMemEnd
, kMidMemBeg
, kMidMemEnd
; // Initialized in __asan_init.
154 static inline bool AddrIsInLowMem(uptr a
) {
155 PROFILE_ASAN_MAPPING();
156 return a
< kLowMemEnd
;
159 static inline bool AddrIsInLowShadow(uptr a
) {
160 PROFILE_ASAN_MAPPING();
161 return a
>= kLowShadowBeg
&& a
<= kLowShadowEnd
;
164 static inline bool AddrIsInHighMem(uptr a
) {
165 PROFILE_ASAN_MAPPING();
166 return a
>= kHighMemBeg
&& a
<= kHighMemEnd
;
169 static inline bool AddrIsInMidMem(uptr a
) {
170 PROFILE_ASAN_MAPPING();
171 return kMidMemBeg
&& a
>= kMidMemBeg
&& a
<= kMidMemEnd
;
174 static inline bool AddrIsInMem(uptr a
) {
175 PROFILE_ASAN_MAPPING();
176 return AddrIsInLowMem(a
) || AddrIsInMidMem(a
) || AddrIsInHighMem(a
);
179 static inline uptr
MemToShadow(uptr p
) {
180 PROFILE_ASAN_MAPPING();
181 CHECK(AddrIsInMem(p
));
182 return MEM_TO_SHADOW(p
);
185 static inline bool AddrIsInHighShadow(uptr a
) {
186 PROFILE_ASAN_MAPPING();
187 return a
>= kHighShadowBeg
&& a
<= kHighMemEnd
;
190 static inline bool AddrIsInMidShadow(uptr a
) {
191 PROFILE_ASAN_MAPPING();
192 return kMidMemBeg
&& a
>= kMidShadowBeg
&& a
<= kMidMemEnd
;
195 static inline bool AddrIsInShadow(uptr a
) {
196 PROFILE_ASAN_MAPPING();
197 return AddrIsInLowShadow(a
) || AddrIsInMidShadow(a
) || AddrIsInHighShadow(a
);
200 static inline bool AddrIsInShadowGap(uptr a
) {
201 PROFILE_ASAN_MAPPING();
203 if (a
<= kShadowGapEnd
)
204 return SHADOW_OFFSET
== 0 || a
>= kShadowGapBeg
;
205 return (a
>= kShadowGap2Beg
&& a
<= kShadowGap2End
) ||
206 (a
>= kShadowGap3Beg
&& a
<= kShadowGap3End
);
208 // In zero-based shadow mode we treat addresses near zero as addresses
209 // in shadow gap as well.
210 if (SHADOW_OFFSET
== 0)
211 return a
<= kShadowGapEnd
;
212 return a
>= kShadowGapBeg
&& a
<= kShadowGapEnd
;
215 static inline bool AddrIsAlignedByGranularity(uptr a
) {
216 PROFILE_ASAN_MAPPING();
217 return (a
& (SHADOW_GRANULARITY
- 1)) == 0;
220 static inline bool AddressIsPoisoned(uptr a
) {
221 PROFILE_ASAN_MAPPING();
222 const uptr kAccessSize
= 1;
223 u8
*shadow_address
= (u8
*)MEM_TO_SHADOW(a
);
224 s8 shadow_value
= *shadow_address
;
226 u8 last_accessed_byte
= (a
& (SHADOW_GRANULARITY
- 1))
228 return (last_accessed_byte
>= shadow_value
);
233 // Must be after all calls to PROFILE_ASAN_MAPPING().
234 static const uptr kAsanMappingProfileSize
= __LINE__
;
236 } // namespace __asan
238 #endif // ASAN_MAPPING_H