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"))) uintptr_t __asan_mapping_scale; 24extern __attribute__((visibility("default"))) uintptr_t __asan_mapping_offset; 25# define SHADOW_SCALE (__asan_mapping_scale) 26# define SHADOW_OFFSET (__asan_mapping_offset) 27#else 28# ifdef 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 44#if __WORDSIZE == 64 45 static const size_t kHighMemEnd = 0x00007fffffffffffUL; 46#else // __WORDSIZE == 32 47 static const size_t kHighMemEnd = 0xffffffff; 48#endif // __WORDSIZE 49 50 51#define kLowMemBeg 0 52#define kLowMemEnd (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0) 53 54#define kLowShadowBeg SHADOW_OFFSET 55#define kLowShadowEnd MEM_TO_SHADOW(kLowMemEnd) 56 57#define kHighMemBeg (MEM_TO_SHADOW(kHighMemEnd) + 1) 58 59#define kHighShadowBeg MEM_TO_SHADOW(kHighMemBeg) 60#define kHighShadowEnd MEM_TO_SHADOW(kHighMemEnd) 61 62#define kShadowGapBeg (kLowShadowEnd ? kLowShadowEnd + 1 : 16 * kPageSize) 63#define kShadowGapEnd (kHighShadowBeg - 1) 64 65#define kGlobalAndStackRedzone \ 66 (SHADOW_GRANULARITY < 32 ? 32 : SHADOW_GRANULARITY) 67 68namespace __asan { 69 70static inline bool AddrIsInLowMem(uintptr_t a) { 71 return a < kLowMemEnd; 72} 73 74static inline bool AddrIsInLowShadow(uintptr_t a) { 75 return a >= kLowShadowBeg && a <= kLowShadowEnd; 76} 77 78static inline bool AddrIsInHighMem(uintptr_t a) { 79 return a >= kHighMemBeg && a <= kHighMemEnd; 80} 81 82static inline bool AddrIsInMem(uintptr_t a) { 83 return AddrIsInLowMem(a) || AddrIsInHighMem(a); 84} 85 86static inline uintptr_t MemToShadow(uintptr_t p) { 87 CHECK(AddrIsInMem(p)); 88 return MEM_TO_SHADOW(p); 89} 90 91static inline bool AddrIsInHighShadow(uintptr_t a) { 92 return a >= kHighShadowBeg && a <= kHighMemEnd; 93} 94 95static inline bool AddrIsInShadow(uintptr_t a) { 96 return AddrIsInLowShadow(a) || AddrIsInHighShadow(a); 97} 98 99static inline bool AddrIsAlignedByGranularity(uintptr_t a) { 100 return (a & (SHADOW_GRANULARITY - 1)) == 0; 101} 102 103static inline bool AddressIsPoisoned(uintptr_t a) { 104 const size_t kAccessSize = 1; 105 uint8_t *shadow_address = (uint8_t*)MemToShadow(a); 106 int8_t shadow_value = *shadow_address; 107 if (shadow_value) { 108 uint8_t last_accessed_byte = (a & (SHADOW_GRANULARITY - 1)) 109 + kAccessSize - 1; 110 return (last_accessed_byte >= shadow_value); 111 } 112 return false; 113} 114 115} // namespace __asan 116 117#endif // ASAN_MAPPING_H 118