1//===-- asan_mapping.h ------------------------------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file is a part of AddressSanitizer, an address sanity checker. 11// 12// Defines ASan memory mapping. 13//===----------------------------------------------------------------------===// 14#ifndef ASAN_MAPPING_H 15#define ASAN_MAPPING_H 16 17#include "asan_internal.h" 18 19// The full explanation of the memory mapping could be found here: 20// http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm 21// 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 || 28// 29// When SHADOW_OFFSET is zero (-pie): 30// || `[0x100000000000, 0x7fffffffffff]` || HighMem || 31// || `[0x020000000000, 0x0fffffffffff]` || HighShadow || 32// || `[0x000000040000, 0x01ffffffffff]` || ShadowGap || 33// 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 || 45// 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 || 52// 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 || 59 60#if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1 61extern SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_scale; 62extern SANITIZER_INTERFACE_ATTRIBUTE uptr __asan_mapping_offset; 63# define SHADOW_SCALE (__asan_mapping_scale) 64# define SHADOW_OFFSET (__asan_mapping_offset) 65#else 66# if SANITIZER_ANDROID 67# define SHADOW_SCALE (3) 68# define SHADOW_OFFSET (0) 69# else 70# define SHADOW_SCALE (3) 71# if SANITIZER_WORDSIZE == 32 72# if defined(__mips__) 73# define SHADOW_OFFSET 0x0aaa8000 74# else 75# define SHADOW_OFFSET (1 << 29) 76# endif 77# else 78# if defined(__powerpc64__) 79# define SHADOW_OFFSET (1ULL << 41) 80# else 81# if SANITIZER_MAC 82# define SHADOW_OFFSET (1ULL << 44) 83# else 84# define SHADOW_OFFSET 0x7fff8000ULL 85# endif 86# endif 87# endif 88# endif 89#endif // ASAN_FLEXIBLE_MAPPING_AND_OFFSET 90 91#define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE) 92#define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET)) 93#define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE) 94 95#define kLowMemBeg 0 96#define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0) 97 98#define kLowShadowBeg SHADOW_OFFSET 99#define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd) 100 101#define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1) 102 103#define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg) 104#define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd) 105 106# define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg) 107# define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd) 108 109// With the zero shadow base we can not actually map pages starting from 0. 110// This constant is somewhat arbitrary. 111#define kZeroBaseShadowStart (1 << 18) 112 113#define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 \ 114 : kZeroBaseShadowStart) 115#define kShadowGapEnd ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1) 116 117#define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0) 118#define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0) 119 120#define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0) 121#define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0) 122 123#define DO_ASAN_MAPPING_PROFILE 0 // Set to 1 to profile the functions below. 124 125#if DO_ASAN_MAPPING_PROFILE 126# define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++; 127#else 128# define PROFILE_ASAN_MAPPING() 129#endif 130 131// If 1, all shadow boundaries are constants. 132// Don't set to 1 other than for testing. 133#define ASAN_FIXED_MAPPING 0 134 135namespace __asan { 136 137extern uptr AsanMappingProfile[]; 138 139#if ASAN_FIXED_MAPPING 140// Fixed mapping for 64-bit Linux. Mostly used for performance comparison 141// with non-fixed mapping. As of r175253 (Feb 2013) the performance 142// difference between fixed and non-fixed mapping is below the noise level. 143static uptr kHighMemEnd = 0x7fffffffffffULL; 144static uptr kMidMemBeg = 0x3000000000ULL; 145static uptr kMidMemEnd = 0x4fffffffffULL; 146#else 147SANITIZER_INTERFACE_ATTRIBUTE 148extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd; // Initialized in __asan_init. 149#endif 150 151static inline bool AddrIsInLowMem(uptr a) { 152 PROFILE_ASAN_MAPPING(); 153 return a < kLowMemEnd; 154} 155 156static inline bool AddrIsInLowShadow(uptr a) { 157 PROFILE_ASAN_MAPPING(); 158 return a >= kLowShadowBeg && a <= kLowShadowEnd; 159} 160 161static inline bool AddrIsInHighMem(uptr a) { 162 PROFILE_ASAN_MAPPING(); 163 return a >= kHighMemBeg && a <= kHighMemEnd; 164} 165 166static inline bool AddrIsInMidMem(uptr a) { 167 PROFILE_ASAN_MAPPING(); 168 return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd; 169} 170 171static inline bool AddrIsInMem(uptr a) { 172 PROFILE_ASAN_MAPPING(); 173 return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a); 174} 175 176static inline uptr MemToShadow(uptr p) { 177 PROFILE_ASAN_MAPPING(); 178 CHECK(AddrIsInMem(p)); 179 return MEM_TO_SHADOW(p); 180} 181 182static inline bool AddrIsInHighShadow(uptr a) { 183 PROFILE_ASAN_MAPPING(); 184 return a >= kHighShadowBeg && a <= kHighMemEnd; 185} 186 187static inline bool AddrIsInMidShadow(uptr a) { 188 PROFILE_ASAN_MAPPING(); 189 return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd; 190} 191 192static inline bool AddrIsInShadow(uptr a) { 193 PROFILE_ASAN_MAPPING(); 194 return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a); 195} 196 197static inline bool AddrIsInShadowGap(uptr a) { 198 PROFILE_ASAN_MAPPING(); 199 if (kMidMemBeg) { 200 if (a <= kShadowGapEnd) 201 return SHADOW_OFFSET == 0 || a >= kShadowGapBeg; 202 return (a >= kShadowGap2Beg && a <= kShadowGap2End) || 203 (a >= kShadowGap3Beg && a <= kShadowGap3End); 204 } 205 // In zero-based shadow mode we treat addresses near zero as addresses 206 // in shadow gap as well. 207 if (SHADOW_OFFSET == 0) 208 return a <= kShadowGapEnd; 209 return a >= kShadowGapBeg && a <= kShadowGapEnd; 210} 211 212static inline bool AddrIsAlignedByGranularity(uptr a) { 213 PROFILE_ASAN_MAPPING(); 214 return (a & (SHADOW_GRANULARITY - 1)) == 0; 215} 216 217static inline bool AddressIsPoisoned(uptr a) { 218 PROFILE_ASAN_MAPPING(); 219 const uptr kAccessSize = 1; 220 u8 *shadow_address = (u8*)MEM_TO_SHADOW(a); 221 s8 shadow_value = *shadow_address; 222 if (shadow_value) { 223 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1)) 224 + kAccessSize - 1; 225 return (last_accessed_byte >= shadow_value); 226 } 227 return false; 228} 229 230// Must be after all calls to PROFILE_ASAN_MAPPING(). 231static const uptr kAsanMappingProfileSize = __LINE__; 232 233} // namespace __asan 234 235#endif // ASAN_MAPPING_H 236