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 {
31 INVALID = 1,
32 ALLOCATOR = 2,
33 APP = 4,
34 SHADOW = 8,
35 ORIGIN = 16,
36 } type;
37 const char *name;
38};
39
40// Note: MappingDesc::ALLOCATOR entries are only used to check for memory
41// layout compatibility. The actual allocation settings are in
42// dfsan_allocator.cpp, which need to be kept in sync.
43#if SANITIZER_LINUX && SANITIZER_WORDSIZE == 64
44
45# if defined(__aarch64__)
46// The mapping assumes 48-bit VMA. AArch64 maps:
47// - 0x0000000000000-0x0100000000000: 39/42/48-bits program own segments
48// - 0x0a00000000000-0x0b00000000000: 48-bits PIE program segments
49// Ideally, this would extend to 0x0c00000000000 (2^45 bytes - the
50// maximum ASLR region for 48-bit VMA) but it is too hard to fit in
51// the larger app/shadow/origin regions.
52// - 0x0e00000000000-0x1000000000000: 48-bits libraries segments
53const MappingDesc kMemoryLayout[] = {
54 {0X0000000000000, 0X0100000000000, MappingDesc::APP, "app-10-13"},
55 {0X0100000000000, 0X0200000000000, MappingDesc::SHADOW, "shadow-14"},
56 {0X0200000000000, 0X0300000000000, MappingDesc::INVALID, "invalid"},
57 {0X0300000000000, 0X0400000000000, MappingDesc::ORIGIN, "origin-14"},
58 {0X0400000000000, 0X0600000000000, MappingDesc::SHADOW, "shadow-15"},
59 {0X0600000000000, 0X0800000000000, MappingDesc::ORIGIN, "origin-15"},
60 {0X0800000000000, 0X0A00000000000, MappingDesc::INVALID, "invalid"},
61 {0X0A00000000000, 0X0B00000000000, MappingDesc::APP, "app-14"},
62 {0X0B00000000000, 0X0C00000000000, MappingDesc::SHADOW, "shadow-10-13"},
63 {0X0C00000000000, 0X0D00000000000, MappingDesc::INVALID, "invalid"},
64 {0X0D00000000000, 0X0E00000000000, MappingDesc::ORIGIN, "origin-10-13"},
65 {0X0E00000000000, 0X0E40000000000, MappingDesc::ALLOCATOR, "allocator"},
66 {0X0E40000000000, 0X1000000000000, MappingDesc::APP, "app-15"},
67};
68# define MEM_TO_SHADOW(mem) ((uptr)mem ^ 0xB00000000000ULL)
69# define SHADOW_TO_ORIGIN(shadow) (((uptr)(shadow)) + 0x200000000000ULL)
70
71# else
72// All of the following configurations are supported.
73// ASLR disabled: main executable and DSOs at 0x555550000000
74// PIE and ASLR: main executable and DSOs at 0x7f0000000000
75// non-PIE: main executable below 0x100000000, DSOs at 0x7f0000000000
76// Heap at 0x700000000000.
77const MappingDesc kMemoryLayout[] = {
78 {.start: 0x000000000000ULL, .end: 0x010000000000ULL, .type: MappingDesc::APP, .name: "app-1"},
79 {.start: 0x010000000000ULL, .end: 0x100000000000ULL, .type: MappingDesc::SHADOW, .name: "shadow-2"},
80 {.start: 0x100000000000ULL, .end: 0x110000000000ULL, .type: MappingDesc::INVALID, .name: "invalid"},
81 {.start: 0x110000000000ULL, .end: 0x200000000000ULL, .type: MappingDesc::ORIGIN, .name: "origin-2"},
82 {.start: 0x200000000000ULL, .end: 0x300000000000ULL, .type: MappingDesc::SHADOW, .name: "shadow-3"},
83 {.start: 0x300000000000ULL, .end: 0x400000000000ULL, .type: MappingDesc::ORIGIN, .name: "origin-3"},
84 {.start: 0x400000000000ULL, .end: 0x500000000000ULL, .type: MappingDesc::INVALID, .name: "invalid"},
85 {.start: 0x500000000000ULL, .end: 0x510000000000ULL, .type: MappingDesc::SHADOW, .name: "shadow-1"},
86 {.start: 0x510000000000ULL, .end: 0x600000000000ULL, .type: MappingDesc::APP, .name: "app-2"},
87 {.start: 0x600000000000ULL, .end: 0x610000000000ULL, .type: MappingDesc::ORIGIN, .name: "origin-1"},
88 {.start: 0x610000000000ULL, .end: 0x700000000000ULL, .type: MappingDesc::INVALID, .name: "invalid"},
89 {.start: 0x700000000000ULL, .end: 0x740000000000ULL, .type: MappingDesc::ALLOCATOR, .name: "allocator"},
90 {.start: 0x740000000000ULL, .end: 0x800000000000ULL, .type: MappingDesc::APP, .name: "app-3"}};
91# define MEM_TO_SHADOW(mem) (((uptr)(mem)) ^ 0x500000000000ULL)
92# define SHADOW_TO_ORIGIN(mem) (((uptr)(mem)) + 0x100000000000ULL)
93# endif
94
95#else
96# error "Unsupported platform"
97#endif
98
99const uptr kMemoryLayoutSize = sizeof(kMemoryLayout) / sizeof(kMemoryLayout[0]);
100
101#define MEM_TO_ORIGIN(mem) (SHADOW_TO_ORIGIN(MEM_TO_SHADOW((mem))))
102
103#ifndef __clang__
104__attribute__((optimize("unroll-loops")))
105#endif
106inline bool
107addr_is_type(uptr addr, int mapping_types) {
108// It is critical for performance that this loop is unrolled (because then it is
109// simplified into just a few constant comparisons).
110#ifdef __clang__
111# pragma unroll
112#endif
113 for (unsigned i = 0; i < kMemoryLayoutSize; ++i)
114 if ((kMemoryLayout[i].type & mapping_types) &&
115 addr >= kMemoryLayout[i].start && addr < kMemoryLayout[i].end)
116 return true;
117 return false;
118}
119
120#define MEM_IS_APP(mem) \
121 (addr_is_type((uptr)(mem), MappingDesc::APP | MappingDesc::ALLOCATOR))
122#define MEM_IS_SHADOW(mem) addr_is_type((uptr)(mem), MappingDesc::SHADOW)
123#define MEM_IS_ORIGIN(mem) addr_is_type((uptr)(mem), MappingDesc::ORIGIN)
124
125} // namespace __dfsan
126
127#endif
128