asan_mapping.h revision 276851 
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 on x86_64 machine:
47// || `[0x40000000, 0xffffffff]` || HighMem    ||
48// || `[0x28000000, 0x3fffffff]` || HighShadow ||
49// || `[0x24000000, 0x27ffffff]` || ShadowGap  ||
50// || `[0x20000000, 0x23ffffff]` || LowShadow  ||
51// || `[0x00000000, 0x1fffffff]` || LowMem     ||
52//
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     ||
61//
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     ||
68//
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     ||
75//
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     ||
82
83static const u64 kDefaultShadowScale = 3;
84static const u64 kDefaultShadowOffset32 = 1ULL << 29;  // 0x20000000
85static const u64 kIosShadowOffset32 = 1ULL << 30;  // 0x40000000
86static const u64 kDefaultShadowOffset64 = 1ULL << 44;
87static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000;  // < 2G.
88static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
89static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
90static const u64 kMIPS64_ShadowOffset64 = 1ULL << 36;
91static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
92static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30;  // 0x40000000
93static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
94
95#define SHADOW_SCALE kDefaultShadowScale
96#if SANITIZER_ANDROID
97# define SHADOW_OFFSET (0)
98#else
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
104#  else
105#    if SANITIZER_IOS
106#      define SHADOW_OFFSET kIosShadowOffset32
107#    else
108#      define SHADOW_OFFSET kDefaultShadowOffset32
109#    endif
110#  endif
111# else
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
118#  elif SANITIZER_MAC
119#   define SHADOW_OFFSET kDefaultShadowOffset64
120#  elif defined(__mips64)
121#   define SHADOW_OFFSET kMIPS64_ShadowOffset64
122#  else
123#   define SHADOW_OFFSET kDefaultShort64bitShadowOffset
124#  endif
125# endif
126#endif
127
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)
131
132#define kLowMemBeg      0
133#define kLowMemEnd      (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
134
135#define kLowShadowBeg   SHADOW_OFFSET
136#define kLowShadowEnd   MEM_TO_SHADOW(kLowMemEnd)
137
138#define kHighMemBeg     (MEM_TO_SHADOW(kHighMemEnd) + 1)
139
140#define kHighShadowBeg  MEM_TO_SHADOW(kHighMemBeg)
141#define kHighShadowEnd  MEM_TO_SHADOW(kHighMemEnd)
142
143# define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
144# define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
145
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)
149
150#define kShadowGapBeg   (kLowShadowEnd ? kLowShadowEnd + 1 \
151                                       : kZeroBaseShadowStart)
152#define kShadowGapEnd   ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
153
154#define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
155#define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
156
157#define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
158#define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
159
160#define DO_ASAN_MAPPING_PROFILE 0  // Set to 1 to profile the functions below.
161
162#if DO_ASAN_MAPPING_PROFILE
163# define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
164#else
165# define PROFILE_ASAN_MAPPING()
166#endif
167
168// If 1, all shadow boundaries are constants.
169// Don't set to 1 other than for testing.
170#define ASAN_FIXED_MAPPING 0
171
172namespace __asan {
173
174extern uptr AsanMappingProfile[];
175
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.
180static uptr kHighMemEnd = 0x7fffffffffffULL;
181static uptr kMidMemBeg =    0x3000000000ULL;
182static uptr kMidMemEnd =    0x4fffffffffULL;
183#else
184extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd;  // Initialized in __asan_init.
185#endif
186
187static inline bool AddrIsInLowMem(uptr a) {
188  PROFILE_ASAN_MAPPING();
189  return a < kLowMemEnd;
190}
191
192static inline bool AddrIsInLowShadow(uptr a) {
193  PROFILE_ASAN_MAPPING();
194  return a >= kLowShadowBeg && a <= kLowShadowEnd;
195}
196
197static inline bool AddrIsInHighMem(uptr a) {
198  PROFILE_ASAN_MAPPING();
199  return a >= kHighMemBeg && a <= kHighMemEnd;
200}
201
202static inline bool AddrIsInMidMem(uptr a) {
203  PROFILE_ASAN_MAPPING();
204  return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd;
205}
206
207static inline bool AddrIsInMem(uptr a) {
208  PROFILE_ASAN_MAPPING();
209  return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a);
210}
211
212static inline uptr MemToShadow(uptr p) {
213  PROFILE_ASAN_MAPPING();
214  CHECK(AddrIsInMem(p));
215  return MEM_TO_SHADOW(p);
216}
217
218static inline bool AddrIsInHighShadow(uptr a) {
219  PROFILE_ASAN_MAPPING();
220  return a >= kHighShadowBeg && a <= kHighMemEnd;
221}
222
223static inline bool AddrIsInMidShadow(uptr a) {
224  PROFILE_ASAN_MAPPING();
225  return kMidMemBeg && a >= kMidShadowBeg && a <= kMidMemEnd;
226}
227
228static inline bool AddrIsInShadow(uptr a) {
229  PROFILE_ASAN_MAPPING();
230  return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a);
231}
232
233static inline bool AddrIsInShadowGap(uptr a) {
234  PROFILE_ASAN_MAPPING();
235  if (kMidMemBeg) {
236    if (a <= kShadowGapEnd)
237      return SHADOW_OFFSET == 0 || a >= kShadowGapBeg;
238    return (a >= kShadowGap2Beg && a <= kShadowGap2End) ||
239           (a >= kShadowGap3Beg && a <= kShadowGap3End);
240  }
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;
246}
247
248static inline bool AddrIsAlignedByGranularity(uptr a) {
249  PROFILE_ASAN_MAPPING();
250  return (a & (SHADOW_GRANULARITY - 1)) == 0;
251}
252
253static 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;
258  if (shadow_value) {
259    u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1))
260                                 + kAccessSize - 1;
261    return (last_accessed_byte >= shadow_value);
262  }
263  return false;
264}
265
266// Must be after all calls to PROFILE_ASAN_MAPPING().
267static const uptr kAsanMappingProfileSize = __LINE__;
268
269}  // namespace __asan
270
271#endif  // ASAN_MAPPING_H
272