1//===-- dfsan_platform.h ----------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file is a part of DataFlowSanitizer.
10//
11// Platform specific information for DFSan.
12//===----------------------------------------------------------------------===//
13
14#ifndef DFSAN_PLATFORM_H
15#define DFSAN_PLATFORM_H
16
17#include "sanitizer_common/sanitizer_common.h"
18#include "sanitizer_common/sanitizer_platform.h"
19
20namespace __dfsan {
21
22using __sanitizer::uptr;
23
24// TODO: The memory mapping code to setup a 1:1 shadow is based on msan.
25// Consider refactoring these into a shared implementation.
26
27struct MappingDesc {
28  uptr start;
29  uptr end;
30  enum Type { INVALID, APP, SHADOW, ORIGIN } type;
31  const char *name;
32};
33
34#if SANITIZER_LINUX && SANITIZER_WORDSIZE == 64
35
36#  if defined(__aarch64__)
37// The mapping assumes 48-bit VMA. AArch64 maps:
38// - 0x0000000000000-0x0100000000000: 39/42/48-bits program own segments
39// - 0x0a00000000000-0x0b00000000000: 48-bits PIE program segments
40//   Ideally, this would extend to 0x0c00000000000 (2^45 bytes - the
41//   maximum ASLR region for 48-bit VMA) but it is too hard to fit in
42//   the larger app/shadow/origin regions.
43// - 0x0e00000000000-0x1000000000000: 48-bits libraries segments
44const MappingDesc kMemoryLayout[] = {
45    {0X0000000000000, 0X0100000000000, MappingDesc::APP, "app-10-13"},
46    {0X0100000000000, 0X0200000000000, MappingDesc::SHADOW, "shadow-14"},
47    {0X0200000000000, 0X0300000000000, MappingDesc::INVALID, "invalid"},
48    {0X0300000000000, 0X0400000000000, MappingDesc::ORIGIN, "origin-14"},
49    {0X0400000000000, 0X0600000000000, MappingDesc::SHADOW, "shadow-15"},
50    {0X0600000000000, 0X0800000000000, MappingDesc::ORIGIN, "origin-15"},
51    {0X0800000000000, 0X0A00000000000, MappingDesc::INVALID, "invalid"},
52    {0X0A00000000000, 0X0B00000000000, MappingDesc::APP, "app-14"},
53    {0X0B00000000000, 0X0C00000000000, MappingDesc::SHADOW, "shadow-10-13"},
54    {0X0C00000000000, 0X0D00000000000, MappingDesc::INVALID, "invalid"},
55    {0X0D00000000000, 0X0E00000000000, MappingDesc::ORIGIN, "origin-10-13"},
56    {0X0E00000000000, 0X1000000000000, MappingDesc::APP, "app-15"},
57};
58#    define MEM_TO_SHADOW(mem) ((uptr)mem ^ 0xB00000000000ULL)
59#    define SHADOW_TO_ORIGIN(shadow) (((uptr)(shadow)) + 0x200000000000ULL)
60
61#  else
62// All of the following configurations are supported.
63// ASLR disabled: main executable and DSOs at 0x555550000000
64// PIE and ASLR: main executable and DSOs at 0x7f0000000000
65// non-PIE: main executable below 0x100000000, DSOs at 0x7f0000000000
66// Heap at 0x700000000000.
67const MappingDesc kMemoryLayout[] = {
68    {0x000000000000ULL, 0x010000000000ULL, MappingDesc::APP, "app-1"},
69    {0x010000000000ULL, 0x100000000000ULL, MappingDesc::SHADOW, "shadow-2"},
70    {0x100000000000ULL, 0x110000000000ULL, MappingDesc::INVALID, "invalid"},
71    {0x110000000000ULL, 0x200000000000ULL, MappingDesc::ORIGIN, "origin-2"},
72    {0x200000000000ULL, 0x300000000000ULL, MappingDesc::SHADOW, "shadow-3"},
73    {0x300000000000ULL, 0x400000000000ULL, MappingDesc::ORIGIN, "origin-3"},
74    {0x400000000000ULL, 0x500000000000ULL, MappingDesc::INVALID, "invalid"},
75    {0x500000000000ULL, 0x510000000000ULL, MappingDesc::SHADOW, "shadow-1"},
76    {0x510000000000ULL, 0x600000000000ULL, MappingDesc::APP, "app-2"},
77    {0x600000000000ULL, 0x610000000000ULL, MappingDesc::ORIGIN, "origin-1"},
78    {0x610000000000ULL, 0x700000000000ULL, MappingDesc::INVALID, "invalid"},
79    {0x700000000000ULL, 0x800000000000ULL, MappingDesc::APP, "app-3"}};
80#    define MEM_TO_SHADOW(mem) (((uptr)(mem)) ^ 0x500000000000ULL)
81#    define SHADOW_TO_ORIGIN(mem) (((uptr)(mem)) + 0x100000000000ULL)
82#  endif
83
84#else
85#  error "Unsupported platform"
86#endif
87
88const uptr kMemoryLayoutSize = sizeof(kMemoryLayout) / sizeof(kMemoryLayout[0]);
89
90#define MEM_TO_ORIGIN(mem) (SHADOW_TO_ORIGIN(MEM_TO_SHADOW((mem))))
91
92#ifndef __clang__
93__attribute__((optimize("unroll-loops")))
94#endif
95inline bool
96addr_is_type(uptr addr, MappingDesc::Type mapping_type) {
97// It is critical for performance that this loop is unrolled (because then it is
98// simplified into just a few constant comparisons).
99#ifdef __clang__
100#  pragma unroll
101#endif
102  for (unsigned i = 0; i < kMemoryLayoutSize; ++i)
103    if (kMemoryLayout[i].type == mapping_type &&
104        addr >= kMemoryLayout[i].start && addr < kMemoryLayout[i].end)
105      return true;
106  return false;
107}
108
109#define MEM_IS_APP(mem) addr_is_type((uptr)(mem), MappingDesc::APP)
110#define MEM_IS_SHADOW(mem) addr_is_type((uptr)(mem), MappingDesc::SHADOW)
111#define MEM_IS_ORIGIN(mem) addr_is_type((uptr)(mem), MappingDesc::ORIGIN)
112
113}  // namespace __dfsan
114
115#endif
116