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 on x86_64 machine:
47 // || `[0x40000000, 0xffffffff]` || HighMem ||
48 // || `[0x28000000, 0x3fffffff]` || HighShadow ||
49 // || `[0x24000000, 0x27ffffff]` || ShadowGap ||
50 // || `[0x20000000, 0x23ffffff]` || LowShadow ||
51 // || `[0x00000000, 0x1fffffff]` || LowMem ||
53 // Default Linux/i386 mapping on i386 machine
54 // (addresses starting with 0xc0000000 are reserved
55 // for kernel and thus not sanitized):
56 // || `[0x38000000, 0xbfffffff]` || HighMem ||
57 // || `[0x27000000, 0x37ffffff]` || HighShadow ||
58 // || `[0x24000000, 0x26ffffff]` || ShadowGap ||
59 // || `[0x20000000, 0x23ffffff]` || LowShadow ||
60 // || `[0x00000000, 0x1fffffff]` || LowMem ||
62 // Default Linux/MIPS mapping:
63 // || `[0x2aaa0000, 0xffffffff]` || HighMem ||
64 // || `[0x0fff4000, 0x2aa9ffff]` || HighShadow ||
65 // || `[0x0bff4000, 0x0fff3fff]` || ShadowGap ||
66 // || `[0x0aaa0000, 0x0bff3fff]` || LowShadow ||
67 // || `[0x00000000, 0x0aa9ffff]` || LowMem ||
69 // Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
70 // || `[0x500000000000, 0x7fffffffffff]` || HighMem ||
71 // || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow ||
72 // || `[0x480000000000, 0x49ffffffffff]` || ShadowGap ||
73 // || `[0x400000000000, 0x47ffffffffff]` || LowShadow ||
74 // || `[0x000000000000, 0x3fffffffffff]` || LowMem ||
76 // Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000:
77 // || `[0x60000000, 0xffffffff]` || HighMem ||
78 // || `[0x4c000000, 0x5fffffff]` || HighShadow ||
79 // || `[0x48000000, 0x4bffffff]` || ShadowGap ||
80 // || `[0x40000000, 0x47ffffff]` || LowShadow ||
81 // || `[0x00000000, 0x3fffffff]` || LowMem ||
83 static const u64 kDefaultShadowScale = 3;
84 static const u64 kDefaultShadowOffset32 = 1ULL << 29; // 0x20000000
85 static const u64 kIosShadowOffset32 = 1ULL << 30; // 0x40000000
86 static const u64 kDefaultShadowOffset64 = 1ULL << 44;
87 static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G.
88 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
89 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
90 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 36;
91 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
92 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30; // 0x40000000
93 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46; // 0x400000000000
95 #define SHADOW_SCALE kDefaultShadowScale
97 # define SHADOW_OFFSET (0)
99 # if SANITIZER_WORDSIZE == 32
100 # if defined(__mips__)
101 # define SHADOW_OFFSET kMIPS32_ShadowOffset32
102 # elif SANITIZER_FREEBSD
103 # define SHADOW_OFFSET kFreeBSD_ShadowOffset32
106 # define SHADOW_OFFSET kIosShadowOffset32
108 # define SHADOW_OFFSET kDefaultShadowOffset32
112 # if defined(__aarch64__)
113 # define SHADOW_OFFSET kAArch64_ShadowOffset64
114 # elif defined(__powerpc64__)
115 # define SHADOW_OFFSET kPPC64_ShadowOffset64
116 # elif SANITIZER_FREEBSD
117 # define SHADOW_OFFSET kFreeBSD_ShadowOffset64
119 # define SHADOW_OFFSET kDefaultShadowOffset64
120 # elif defined(__mips64)
121 # define SHADOW_OFFSET kMIPS64_ShadowOffset64
123 # define SHADOW_OFFSET kDefaultShort64bitShadowOffset
128 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
129 #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
130 #define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE)
133 #define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
135 #define kLowShadowBeg SHADOW_OFFSET
136 #define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd)
138 #define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1)
140 #define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg)
141 #define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd)
143 # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
144 # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
146 // With the zero shadow base we can not actually map pages starting from 0.
147 // This constant is somewhat arbitrary.
148 #define kZeroBaseShadowStart (1 << 18)
150 #define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \
151 : kZeroBaseShadowStart)
152 #define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
154 #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
155 #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
157 #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
158 #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
160 #define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below.
162 #if DO_ASAN_MAPPING_PROFILE
163 # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
165 # define PROFILE_ASAN_MAPPING()
168 // If 1, all shadow boundaries are constants.
169 // Don't set to 1 other than for testing.
170 #define ASAN_FIXED_MAPPING 0
174 extern uptr AsanMappingProfile[];
176 #if ASAN_FIXED_MAPPING
177 // Fixed mapping for 64-bit Linux. Mostly used for performance comparison
178 // with non-fixed mapping. As of r175253 (Feb 2013) the performance
179 // difference between fixed and non-fixed mapping is below the noise level.
180 static uptr kHighMemEnd = 0x7fffffffffffULL;
181 static uptr kMidMemBeg = 0x3000000000ULL;
182 static uptr kMidMemEnd = 0x4fffffffffULL;
184 extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init.
187 static inline bool AddrIsInLowMem(uptr a) {
188 PROFILE_ASAN_MAPPING();
189 return a < kLowMemEnd;
192 static inline bool AddrIsInLowShadow(uptr a) {
193 PROFILE_ASAN_MAPPING();
194 return a >= kLowShadowBeg && a <= kLowShadowEnd;
197 static inline bool AddrIsInHighMem(uptr a) {
198 PROFILE_ASAN_MAPPING();
199 return a >= kHighMemBeg && a <= kHighMemEnd;
202 static inline bool AddrIsInMidMem(uptr a) {
203 PROFILE_ASAN_MAPPING();
204 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd;
207 static inline bool AddrIsInMem(uptr a) {
208 PROFILE_ASAN_MAPPING();
209 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a);
212 static inline uptr MemToShadow(uptr p) {
213 PROFILE_ASAN_MAPPING();
214 CHECK(AddrIsInMem(p));
215 return MEM_TO_SHADOW(p);
218 static inline bool AddrIsInHighShadow(uptr a) {
219 PROFILE_ASAN_MAPPING();
220 return a >= kHighShadowBeg && a <= kHighMemEnd;
223 static inline bool AddrIsInMidShadow(uptr a) {
224 PROFILE_ASAN_MAPPING();
225 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd;
228 static inline bool AddrIsInShadow(uptr a) {
229 PROFILE_ASAN_MAPPING();
230 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a);
233 static inline bool AddrIsInShadowGap(uptr a) {
234 PROFILE_ASAN_MAPPING();
236 if (a <= kShadowGapEnd)
237 return SHADOW_OFFSET == 0 || a >= kShadowGapBeg;
238 return (a >= kShadowGap2Beg && a <= kShadowGap2End) ||
239 (a >= kShadowGap3Beg && a <= kShadowGap3End);
241 // In zero-based shadow mode we treat addresses near zero as addresses
242 // in shadow gap as well.
243 if (SHADOW_OFFSET == 0)
244 return a <= kShadowGapEnd;
245 return a >= kShadowGapBeg && a <= kShadowGapEnd;
248 static inline bool AddrIsAlignedByGranularity(uptr a) {
249 PROFILE_ASAN_MAPPING();
250 return (a & (SHADOW_GRANULARITY - 1)) == 0;
253 static inline bool AddressIsPoisoned(uptr a) {
254 PROFILE_ASAN_MAPPING();
255 const uptr kAccessSize = 1;
256 u8 *shadow_address = (u8*)MEM_TO_SHADOW(a);
257 s8 shadow_value = *shadow_address;
259 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1))
261 return (last_accessed_byte >= shadow_value);
266 // Must be after all calls to PROFILE_ASAN_MAPPING().
267 static const uptr kAsanMappingProfileSize = __LINE__;
269 } // namespace __asan
271 #endif // ASAN_MAPPING_H