text: //===-- asan_mapping.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 AddressSanitizer, an address sanity checker.
  //
  // Defines ASan memory mapping.
  //===----------------------------------------------------------------------===//
  #ifndef ASAN_MAPPING_H
  #define ASAN_MAPPING_H
  
  #include "asan_internal.h"
  
  // The full explanation of the memory mapping could be found here:
  // https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm
  //
  // Typical shadow mapping on Linux/x86_64 with SHADOW_OFFSET == 0x00007fff8000:
  // || `[0x10007fff8000, 0x7fffffffffff]` || HighMem    ||
  // || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
  // || `[0x00008fff7000, 0x02008fff6fff]` || ShadowGap  ||
  // || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow  ||
  // || `[0x000000000000, 0x00007fff7fff]` || LowMem     ||
  //
  // When SHADOW_OFFSET is zero (-pie):
  // || `[0x100000000000, 0x7fffffffffff]` || HighMem    ||
  // || `[0x020000000000, 0x0fffffffffff]` || HighShadow ||
  // || `[0x000000040000, 0x01ffffffffff]` || ShadowGap  ||
  //
  // Special case when something is already mapped between
  // 0x003000000000 and 0x005000000000 (e.g. when prelink is installed):
  // || `[0x10007fff8000, 0x7fffffffffff]` || HighMem    ||
  // || `[0x02008fff7000, 0x10007fff7fff]` || HighShadow ||
  // || `[0x005000000000, 0x02008fff6fff]` || ShadowGap3 ||
  // || `[0x003000000000, 0x004fffffffff]` || MidMem     ||
  // || `[0x000a7fff8000, 0x002fffffffff]` || ShadowGap2 ||
  // || `[0x00067fff8000, 0x000a7fff7fff]` || MidShadow  ||
  // || `[0x00008fff7000, 0x00067fff7fff]` || ShadowGap  ||
  // || `[0x00007fff8000, 0x00008fff6fff]` || LowShadow  ||
  // || `[0x000000000000, 0x00007fff7fff]` || LowMem     ||
  //
  // Default Linux/i386 mapping on x86_64 machine:
  // || `[0x40000000, 0xffffffff]` || HighMem    ||
  // || `[0x28000000, 0x3fffffff]` || HighShadow ||
  // || `[0x24000000, 0x27ffffff]` || ShadowGap  ||
  // || `[0x20000000, 0x23ffffff]` || LowShadow  ||
  // || `[0x00000000, 0x1fffffff]` || LowMem     ||
  //
  // Default Linux/i386 mapping on i386 machine
  // (addresses starting with 0xc0000000 are reserved
  // for kernel and thus not sanitized):
  // || `[0x38000000, 0xbfffffff]` || HighMem    ||
  // || `[0x27000000, 0x37ffffff]` || HighShadow ||
  // || `[0x24000000, 0x26ffffff]` || ShadowGap  ||
  // || `[0x20000000, 0x23ffffff]` || LowShadow  ||
  // || `[0x00000000, 0x1fffffff]` || LowMem     ||
  //
  // Default Linux/MIPS32 mapping:
  // || `[0x2aaa0000, 0xffffffff]` || HighMem    ||
  // || `[0x0fff4000, 0x2aa9ffff]` || HighShadow ||
  // || `[0x0bff4000, 0x0fff3fff]` || ShadowGap  ||
  // || `[0x0aaa0000, 0x0bff3fff]` || LowShadow  ||
  // || `[0x00000000, 0x0aa9ffff]` || LowMem     ||
  //
  // Default Linux/MIPS64 mapping:
  // || `[0x4000000000, 0xffffffffff]` || HighMem    ||
  // || `[0x2800000000, 0x3fffffffff]` || HighShadow ||
  // || `[0x2400000000, 0x27ffffffff]` || ShadowGap  ||
  // || `[0x2000000000, 0x23ffffffff]` || LowShadow  ||
  // || `[0x0000000000, 0x1fffffffff]` || LowMem     ||
  //
  // Default Linux/AArch64 (39-bit VMA) mapping:
  // || `[0x2000000000, 0x7fffffffff]` || highmem    ||
  // || `[0x1400000000, 0x1fffffffff]` || highshadow ||
  // || `[0x1200000000, 0x13ffffffff]` || shadowgap  ||
  // || `[0x1000000000, 0x11ffffffff]` || lowshadow  ||
  // || `[0x0000000000, 0x0fffffffff]` || lowmem     ||
  //
  // Default Linux/AArch64 (42-bit VMA) mapping:
  // || `[0x10000000000, 0x3ffffffffff]` || highmem    ||
  // || `[0x0a000000000, 0x0ffffffffff]` || highshadow ||
  // || `[0x09000000000, 0x09fffffffff]` || shadowgap  ||
  // || `[0x08000000000, 0x08fffffffff]` || lowshadow  ||
  // || `[0x00000000000, 0x07fffffffff]` || lowmem     ||
  //
  // Default Linux/S390 mapping:
  // || `[0x30000000, 0x7fffffff]` || HighMem    ||
  // || `[0x26000000, 0x2fffffff]` || HighShadow ||
  // || `[0x24000000, 0x25ffffff]` || ShadowGap  ||
  // || `[0x20000000, 0x23ffffff]` || LowShadow  ||
  // || `[0x00000000, 0x1fffffff]` || LowMem     ||
  //
  // Default Linux/SystemZ mapping:
  // || `[0x14000000000000, 0x1fffffffffffff]` || HighMem    ||
  // || `[0x12800000000000, 0x13ffffffffffff]` || HighShadow ||
  // || `[0x12000000000000, 0x127fffffffffff]` || ShadowGap  ||
  // || `[0x10000000000000, 0x11ffffffffffff]` || LowShadow  ||
  // || `[0x00000000000000, 0x0fffffffffffff]` || LowMem     ||
  //
  // Default Linux/SPARC64 (52-bit VMA) mapping:
  // || `[0x8000000000000, 0xfffffffffffff]` || HighMem    ||
  // || `[0x1080000000000, 0x207ffffffffff]` || HighShadow ||
  // || `[0x0090000000000, 0x107ffffffffff]` || ShadowGap  ||
  // || `[0x0080000000000, 0x008ffffffffff]` || LowShadow  ||
  // || `[0x0000000000000, 0x007ffffffffff]` || LowMem     ||
  //
  // Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
  // || `[0x500000000000, 0x7fffffffffff]` || HighMem    ||
  // || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow ||
  // || `[0x480000000000, 0x49ffffffffff]` || ShadowGap  ||
  // || `[0x400000000000, 0x47ffffffffff]` || LowShadow  ||
  // || `[0x000000000000, 0x3fffffffffff]` || LowMem     ||
  //
  // Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000:
  // || `[0x60000000, 0xffffffff]` || HighMem    ||
  // || `[0x4c000000, 0x5fffffff]` || HighShadow ||
  // || `[0x48000000, 0x4bffffff]` || ShadowGap  ||
  // || `[0x40000000, 0x47ffffff]` || LowShadow  ||
  // || `[0x00000000, 0x3fffffff]` || LowMem     ||
  //
  // Shadow mapping on NetBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
  // || `[0x4feffffffe01, 0x7f7ffffff000]` || HighMem    ||
  // || `[0x49fdffffffc0, 0x4feffffffe00]` || HighShadow ||
  // || `[0x480000000000, 0x49fdffffffbf]` || ShadowGap  ||
  // || `[0x400000000000, 0x47ffffffffff]` || LowShadow  ||
  // || `[0x000000000000, 0x3fffffffffff]` || LowMem     ||
  //
  // Shadow mapping on NetBSD/i386 with SHADOW_OFFSET == 0x40000000:
  // || `[0x60000000, 0xfffff000]` || HighMem    ||
  // || `[0x4c000000, 0x5fffffff]` || HighShadow ||
  // || `[0x48000000, 0x4bffffff]` || ShadowGap  ||
  // || `[0x40000000, 0x47ffffff]` || LowShadow  ||
  // || `[0x00000000, 0x3fffffff]` || LowMem     ||
  //
  // Default Windows/i386 mapping:
  // (the exact location of HighShadow/HighMem may vary depending
  //  on WoW64, /LARGEADDRESSAWARE, etc).
  // || `[0x50000000, 0xffffffff]` || HighMem    ||
  // || `[0x3a000000, 0x4fffffff]` || HighShadow ||
  // || `[0x36000000, 0x39ffffff]` || ShadowGap  ||
  // || `[0x30000000, 0x35ffffff]` || LowShadow  ||
  // || `[0x00000000, 0x2fffffff]` || LowMem     ||
  //
  // Shadow mapping on Myriad2 (for shadow scale 5):
  // || `[0x9ff80000, 0x9fffffff]` || ShadowGap  ||
  // || `[0x9f000000, 0x9ff7ffff]` || LowShadow  ||
  // || `[0x80000000, 0x9effffff]` || LowMem     ||
  // || `[0x00000000, 0x7fffffff]` || Ignored    ||
  
  #if defined(ASAN_SHADOW_SCALE)
  static const u64 kDefaultShadowScale = ASAN_SHADOW_SCALE;
  #else
  static const u64 kDefaultShadowScale = SANITIZER_MYRIAD2 ? 5 : 3;
  #endif
  static const u64 kDefaultShadowSentinel = ~(uptr)0;
  static const u64 kDefaultShadowOffset32 = 1ULL << 29;  // 0x20000000
  static const u64 kDefaultShadowOffset64 = 1ULL << 44;
  static const u64 kDefaultShort64bitShadowOffset =
      0x7FFFFFFF & (~0xFFFULL << kDefaultShadowScale);  // < 2G.
  static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
  static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
  static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37;
  static const u64 kPPC64_ShadowOffset64 = 1ULL << 44;
  static const u64 kSystemZ_ShadowOffset64 = 1ULL << 52;
  static const u64 kSPARC64_ShadowOffset64 = 1ULL << 43;  // 0x80000000000
  static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30;  // 0x40000000
  static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
  static const u64 kNetBSD_ShadowOffset32 = 1ULL << 30;  // 0x40000000
  static const u64 kNetBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
  static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
  
  static const u64 kMyriadMemoryOffset32 = 0x80000000ULL;
  static const u64 kMyriadMemorySize32 = 0x20000000ULL;
  static const u64 kMyriadMemoryEnd32 =
      kMyriadMemoryOffset32 + kMyriadMemorySize32 - 1;
  static const u64 kMyriadShadowOffset32 =
      (kMyriadMemoryOffset32 + kMyriadMemorySize32 -
       (kMyriadMemorySize32 >> kDefaultShadowScale));
  static const u64 kMyriadCacheBitMask32 = 0x40000000ULL;
  
  #define SHADOW_SCALE kDefaultShadowScale
  
  #if SANITIZER_FUCHSIA
  #  define SHADOW_OFFSET (0)
  #elif SANITIZER_WORDSIZE == 32
  #  if SANITIZER_ANDROID
  #    define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
  #  elif defined(__mips__)
  #    define SHADOW_OFFSET kMIPS32_ShadowOffset32
  #  elif SANITIZER_FREEBSD
  #    define SHADOW_OFFSET kFreeBSD_ShadowOffset32
  #  elif SANITIZER_NETBSD
  #    define SHADOW_OFFSET kNetBSD_ShadowOffset32
  #  elif SANITIZER_WINDOWS
  #    define SHADOW_OFFSET kWindowsShadowOffset32
  #  elif SANITIZER_IOS
  #    define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
  #  elif SANITIZER_MYRIAD2
  #    define SHADOW_OFFSET kMyriadShadowOffset32
  #  else
  #    define SHADOW_OFFSET kDefaultShadowOffset32
  #  endif
  #else
  #  if SANITIZER_IOS
  #    define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
  #  elif defined(__aarch64__)
  #    define SHADOW_OFFSET kAArch64_ShadowOffset64
  #  elif defined(__powerpc64__)
  #    define SHADOW_OFFSET kPPC64_ShadowOffset64
  #  elif defined(__s390x__)
  #    define SHADOW_OFFSET kSystemZ_ShadowOffset64
  #  elif SANITIZER_FREEBSD && !defined(__mips64)
  #    define SHADOW_OFFSET kFreeBSD_ShadowOffset64
  #  elif SANITIZER_NETBSD
  #    define SHADOW_OFFSET kNetBSD_ShadowOffset64
  #  elif SANITIZER_MAC
  #   define SHADOW_OFFSET kDefaultShadowOffset64
  #  elif defined(__mips64)
  #   define SHADOW_OFFSET kMIPS64_ShadowOffset64
  #elif defined(__sparc__)
  #define SHADOW_OFFSET kSPARC64_ShadowOffset64
  #  elif SANITIZER_WINDOWS64
  #   define SHADOW_OFFSET __asan_shadow_memory_dynamic_address
  #  else
  #   define SHADOW_OFFSET kDefaultShort64bitShadowOffset
  #  endif
  #endif
  
  #if SANITIZER_ANDROID && defined(__arm__)
  # define ASAN_PREMAP_SHADOW 1
  #else
  # define ASAN_PREMAP_SHADOW 0
  #endif
  
  #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)
  
  #define DO_ASAN_MAPPING_PROFILE 0  // Set to 1 to profile the functions below.
  
  #if DO_ASAN_MAPPING_PROFILE
  # define PROFILE_ASAN_MAPPING() AsanMappingProfile[__LINE__]++;
  #else
  # define PROFILE_ASAN_MAPPING()
  #endif
  
  // If 1, all shadow boundaries are constants.
  // Don't set to 1 other than for testing.
  #define ASAN_FIXED_MAPPING 0
  
  namespace __asan {
  
  extern uptr AsanMappingProfile[];
  
  #if ASAN_FIXED_MAPPING
  // Fixed mapping for 64-bit Linux. Mostly used for performance comparison
  // with non-fixed mapping. As of r175253 (Feb 2013) the performance
  // difference between fixed and non-fixed mapping is below the noise level.
  static uptr kHighMemEnd = 0x7fffffffffffULL;
  static uptr kMidMemBeg =    0x3000000000ULL;
  static uptr kMidMemEnd =    0x4fffffffffULL;
  #else
  extern uptr kHighMemEnd, kMidMemBeg, kMidMemEnd;  // Initialized in __asan_init.
  #endif
  
  }  // namespace __asan
  
  #if SANITIZER_MYRIAD2
  #include "asan_mapping_myriad.h"
  #elif defined(__sparc__) && SANITIZER_WORDSIZE == 64
  #include "asan_mapping_sparc64.h"
  #else
  #define MEM_TO_SHADOW(mem) (((mem) >> SHADOW_SCALE) + (SHADOW_OFFSET))
  
  #define kLowMemBeg      0
  #define kLowMemEnd      (SHADOW_OFFSET ? SHADOW_OFFSET - 1 : 0)
  
  #define kLowShadowBeg   SHADOW_OFFSET
  #define kLowShadowEnd   MEM_TO_SHADOW(kLowMemEnd)
  
  #define kHighMemBeg     (MEM_TO_SHADOW(kHighMemEnd) + 1)
  
  #define kHighShadowBeg  MEM_TO_SHADOW(kHighMemBeg)
  #define kHighShadowEnd  MEM_TO_SHADOW(kHighMemEnd)
  
  # define kMidShadowBeg MEM_TO_SHADOW(kMidMemBeg)
  # define kMidShadowEnd MEM_TO_SHADOW(kMidMemEnd)
  
  // With the zero shadow base we can not actually map pages starting from 0.
  // This constant is somewhat arbitrary.
  #define kZeroBaseShadowStart 0
  #define kZeroBaseMaxShadowStart (1 << 18)
  
  #define kShadowGapBeg   (kLowShadowEnd ? kLowShadowEnd + 1 \
                                         : kZeroBaseShadowStart)
  #define kShadowGapEnd   ((kMidMemBeg ? kMidShadowBeg : kHighShadowBeg) - 1)
  
  #define kShadowGap2Beg (kMidMemBeg ? kMidShadowEnd + 1 : 0)
  #define kShadowGap2End (kMidMemBeg ? kMidMemBeg - 1 : 0)
  
  #define kShadowGap3Beg (kMidMemBeg ? kMidMemEnd + 1 : 0)
  #define kShadowGap3End (kMidMemBeg ? kHighShadowBeg - 1 : 0)
  
  namespace __asan {
  
  static inline bool AddrIsInLowMem(uptr a) {
    PROFILE_ASAN_MAPPING();
    return a <= kLowMemEnd;
  }
  
  static inline bool AddrIsInLowShadow(uptr a) {
    PROFILE_ASAN_MAPPING();
    return a >= kLowShadowBeg && a <= kLowShadowEnd;
  }
  
  static inline bool AddrIsInMidMem(uptr a) {
    PROFILE_ASAN_MAPPING();
    return kMidMemBeg && a >= kMidMemBeg && a <= kMidMemEnd;
  }
  
  static inline bool AddrIsInMidShadow(uptr a) {
    PROFILE_ASAN_MAPPING();
    return kMidMemBeg && a >= kMidShadowBeg && a <= kMidShadowEnd;
  }
  
  static inline bool AddrIsInHighMem(uptr a) {
    PROFILE_ASAN_MAPPING();
    return kHighMemBeg && a >= kHighMemBeg && a <= kHighMemEnd;
  }
  
  static inline bool AddrIsInHighShadow(uptr a) {
    PROFILE_ASAN_MAPPING();
    return kHighMemBeg && a >= kHighShadowBeg && a <= kHighShadowEnd;
  }
  
  static inline bool AddrIsInShadowGap(uptr a) {
    PROFILE_ASAN_MAPPING();
    if (kMidMemBeg) {
      if (a <= kShadowGapEnd)
        return SHADOW_OFFSET == 0 || a >= kShadowGapBeg;
      return (a >= kShadowGap2Beg && a <= kShadowGap2End) ||
             (a >= kShadowGap3Beg && a <= kShadowGap3End);
    }
    // In zero-based shadow mode we treat addresses near zero as addresses
    // in shadow gap as well.
    if (SHADOW_OFFSET == 0)
      return a <= kShadowGapEnd;
    return a >= kShadowGapBeg && a <= kShadowGapEnd;
  }
  
  }  // namespace __asan
  
  #endif  // SANITIZER_MYRIAD2
  
  namespace __asan {
  
  static inline bool AddrIsInMem(uptr a) {
    PROFILE_ASAN_MAPPING();
    return AddrIsInLowMem(a) || AddrIsInMidMem(a) || AddrIsInHighMem(a) ||
        (flags()->protect_shadow_gap == 0 && AddrIsInShadowGap(a));
  }
  
  static inline uptr MemToShadow(uptr p) {
    PROFILE_ASAN_MAPPING();
    CHECK(AddrIsInMem(p));
    return MEM_TO_SHADOW(p);
  }
  
  static inline bool AddrIsInShadow(uptr a) {
    PROFILE_ASAN_MAPPING();
    return AddrIsInLowShadow(a) || AddrIsInMidShadow(a) || AddrIsInHighShadow(a);
  }
  
  static inline bool AddrIsAlignedByGranularity(uptr a) {
    PROFILE_ASAN_MAPPING();
    return (a & (SHADOW_GRANULARITY - 1)) == 0;
  }
  
  static inline bool AddressIsPoisoned(uptr a) {
    PROFILE_ASAN_MAPPING();
    if (SANITIZER_MYRIAD2 && !AddrIsInMem(a) && !AddrIsInShadow(a))
      return false;
    const uptr kAccessSize = 1;
    u8 *shadow_address = (u8*)MEM_TO_SHADOW(a);
    s8 shadow_value = *shadow_address;
    if (shadow_value) {
      u8 last_accessed_byte = (a & (SHADOW_GRANULARITY - 1))
                                   + kAccessSize - 1;
      return (last_accessed_byte >= shadow_value);
    }
    return false;
  }
  
  // Must be after all calls to PROFILE_ASAN_MAPPING().
  static const uptr kAsanMappingProfileSize = __LINE__;
  
  }  // namespace __asan
  
  #endif  // ASAN_MAPPING_H
  