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#if ASAN_FLEXIBLE_MAPPING_AND_OFFSET == 1 23extern __attribute__((visibility("default"))) uptr __asan_mapping_scale; 24extern __attribute__((visibility("default"))) uptr __asan_mapping_offset; 25# define SHADOW_SCALE (__asan_mapping_scale) 26# define SHADOW_OFFSET (__asan_mapping_offset) 27#else 28# if ASAN_ANDROID 29# define SHADOW_SCALE (3) 30# define SHADOW_OFFSET (0) 31# else 32# define SHADOW_SCALE (3) 33# if __WORDSIZE == 32 34# define SHADOW_OFFSET (1 << 29) 35# else 36# define SHADOW_OFFSET (1ULL << 44) 37# endif 38# endif 39#endif // ASAN_FLEXIBLE_MAPPING_AND_OFFSET 40 41#define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE) 42#define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) | (SHADOW_OFFSET)) 43#define SHADOW_TO_MEM(shadow) (((shadow) - SHADOW_OFFSET) << SHADOW_SCALE) 44 45#if __WORDSIZE == 64 46 static const uptr kHighMemEnd = 0x00007fffffffffffUL; 47#else // __WORDSIZE == 32 48 static const uptr kHighMemEnd = 0xffffffff; 49#endif // __WORDSIZE 50 51 52#define kLowMemBeg 0 53#define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0) 54 55#define kLowShadowBeg SHADOW_OFFSET 56#define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd) 57 58#define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1) 59 60#define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg) 61#define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd) 62 63#define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 : 16 * kPageSize) 64#define kShadowGapEnd (kHighShadowBeg - 1) 65 66#define kGlobalAndStackRedzone \ 67 (SHADOW_GRANULARITY < 32 ? 32 : SHADOW_GRANULARITY) 68 69namespace __asan { 70 71static inline bool AddrIsInLowMem(uptr a) { 72 return a < kLowMemEnd; 73} 74 75static inline bool AddrIsInLowShadow(uptr a) { 76 return a >= kLowShadowBeg && a <= kLowShadowEnd; 77} 78 79static inline bool AddrIsInHighMem(uptr a) { 80 return a >= kHighMemBeg && a <= kHighMemEnd; 81} 82 83static inline bool AddrIsInMem(uptr a) { 84 return AddrIsInLowMem(a) || AddrIsInHighMem(a); 85} 86 87static inline uptr MemToShadow(uptr p) { 88 CHECK(AddrIsInMem(p)); 89 return MEM_TO_SHADOW(p); 90} 91 92static inline bool AddrIsInHighShadow(uptr a) { 93 return a >= kHighShadowBeg && a <= kHighMemEnd; 94} 95 96static inline bool AddrIsInShadow(uptr a) { 97 return AddrIsInLowShadow(a) || AddrIsInHighShadow(a); 98} 99 100static inline bool AddrIsInShadowGap(uptr a) { 101 return a >= kShadowGapBeg && a <= kShadowGapEnd; 102} 103 104static inline bool AddrIsAlignedByGranularity(uptr a) { 105 return (a & (SHADOW_GRANULARITY - 1)) == 0; 106} 107 108static inline bool AddressIsPoisoned(uptr a) { 109 const uptr kAccessSize = 1; 110 u8 *shadow_address = (u8*)MemToShadow(a); 111 s8 shadow_value = *shadow_address; 112 if (shadow_value) { 113 u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1)) 114 + kAccessSize - 1; 115 return (last_accessed_byte >= shadow_value); 116 } 117 return false; 118} 119 120} // namespace __asan 121 122#endif // ASAN_MAPPING_H 123