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//===-- dfsan_platform.h ----------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of DataFlowSanitizer.
//
// Platform specific information for DFSan.
//===----------------------------------------------------------------------===//
#ifndef DFSAN_PLATFORM_H
#define DFSAN_PLATFORM_H
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_platform.h"
namespace __dfsan {
using __sanitizer::uptr;
// TODO: The memory mapping code to setup a 1:1 shadow is based on msan.
// Consider refactoring these into a shared implementation.
struct MappingDesc {
uptr start;
uptr end;
enum Type { INVALID, APP, SHADOW, ORIGIN } type;
const char *name;
};
#if SANITIZER_LINUX && SANITIZER_WORDSIZE == 64
# if defined(__aarch64__)
// The mapping assumes 48-bit VMA. AArch64 maps:
// - 0x0000000000000-0x0100000000000: 39/42/48-bits program own segments
// - 0x0a00000000000-0x0b00000000000: 48-bits PIE program segments
// Ideally, this would extend to 0x0c00000000000 (2^45 bytes - the
// maximum ASLR region for 48-bit VMA) but it is too hard to fit in
// the larger app/shadow/origin regions.
// - 0x0e00000000000-0x1000000000000: 48-bits libraries segments
const MappingDesc kMemoryLayout[] = {
{0X0000000000000, 0X0100000000000, MappingDesc::APP, "app-10-13"},
{0X0100000000000, 0X0200000000000, MappingDesc::SHADOW, "shadow-14"},
{0X0200000000000, 0X0300000000000, MappingDesc::INVALID, "invalid"},
{0X0300000000000, 0X0400000000000, MappingDesc::ORIGIN, "origin-14"},
{0X0400000000000, 0X0600000000000, MappingDesc::SHADOW, "shadow-15"},
{0X0600000000000, 0X0800000000000, MappingDesc::ORIGIN, "origin-15"},
{0X0800000000000, 0X0A00000000000, MappingDesc::INVALID, "invalid"},
{0X0A00000000000, 0X0B00000000000, MappingDesc::APP, "app-14"},
{0X0B00000000000, 0X0C00000000000, MappingDesc::SHADOW, "shadow-10-13"},
{0X0C00000000000, 0X0D00000000000, MappingDesc::INVALID, "invalid"},
{0X0D00000000000, 0X0E00000000000, MappingDesc::ORIGIN, "origin-10-13"},
{0X0E00000000000, 0X1000000000000, MappingDesc::APP, "app-15"},
};
# define MEM_TO_SHADOW(mem) ((uptr)mem ^ 0xB00000000000ULL)
# define SHADOW_TO_ORIGIN(shadow) (((uptr)(shadow)) + 0x200000000000ULL)
# else
// All of the following configurations are supported.
// ASLR disabled: main executable and DSOs at 0x555550000000
// PIE and ASLR: main executable and DSOs at 0x7f0000000000
// non-PIE: main executable below 0x100000000, DSOs at 0x7f0000000000
// Heap at 0x700000000000.
const MappingDesc kMemoryLayout[] = {
{0x000000000000ULL, 0x010000000000ULL, MappingDesc::APP, "app-1"},
{0x010000000000ULL, 0x100000000000ULL, MappingDesc::SHADOW, "shadow-2"},
{0x100000000000ULL, 0x110000000000ULL, MappingDesc::INVALID, "invalid"},
{0x110000000000ULL, 0x200000000000ULL, MappingDesc::ORIGIN, "origin-2"},
{0x200000000000ULL, 0x300000000000ULL, MappingDesc::SHADOW, "shadow-3"},
{0x300000000000ULL, 0x400000000000ULL, MappingDesc::ORIGIN, "origin-3"},
{0x400000000000ULL, 0x500000000000ULL, MappingDesc::INVALID, "invalid"},
{0x500000000000ULL, 0x510000000000ULL, MappingDesc::SHADOW, "shadow-1"},
{0x510000000000ULL, 0x600000000000ULL, MappingDesc::APP, "app-2"},
{0x600000000000ULL, 0x610000000000ULL, MappingDesc::ORIGIN, "origin-1"},
{0x610000000000ULL, 0x700000000000ULL, MappingDesc::INVALID, "invalid"},
{0x700000000000ULL, 0x800000000000ULL, MappingDesc::APP, "app-3"}};
# define MEM_TO_SHADOW(mem) (((uptr)(mem)) ^ 0x500000000000ULL)
# define SHADOW_TO_ORIGIN(mem) (((uptr)(mem)) + 0x100000000000ULL)
# endif
#else
# error "Unsupported platform"
#endif
const uptr kMemoryLayoutSize = sizeof(kMemoryLayout) / sizeof(kMemoryLayout[0]);
#define MEM_TO_ORIGIN(mem) (SHADOW_TO_ORIGIN(MEM_TO_SHADOW((mem))))
#ifndef __clang__
__attribute__((optimize("unroll-loops")))
#endif
inline bool
addr_is_type(uptr addr, MappingDesc::Type mapping_type) {
// It is critical for performance that this loop is unrolled (because then it is
// simplified into just a few constant comparisons).
#ifdef __clang__
# pragma unroll
#endif
for (unsigned i = 0; i < kMemoryLayoutSize; ++i)
if (kMemoryLayout[i].type == mapping_type &&
addr >= kMemoryLayout[i].start && addr < kMemoryLayout[i].end)
return true;
return false;
}
#define MEM_IS_APP(mem) addr_is_type((uptr)(mem), MappingDesc::APP)
#define MEM_IS_SHADOW(mem) addr_is_type((uptr)(mem), MappingDesc::SHADOW)
#define MEM_IS_ORIGIN(mem) addr_is_type((uptr)(mem), MappingDesc::ORIGIN)
} // namespace __dfsan
#endif
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