1    :  // Copyright 2014 Google Inc. All Rights Reserved.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  //
  15    :  // Declares some constants that are used across Asan.
  16    :  
  17    :  #ifndef SYZYGY_AGENT_ASAN_CONSTANTS_H_
  18    :  #define SYZYGY_AGENT_ASAN_CONSTANTS_H_
  19    :  
  20  m :  namespace agent {
  21  m :  namespace asan {
  22    :  
  23    :  // The ratio of shadow memory to actual memory. This governs the behaviour, size
  24    :  // and alignment requirements of many Asan structures.
  25  m :  static const size_t kShadowRatioLog = 3;
  26  m :  static const size_t kShadowRatio = (1 << kShadowRatioLog);
  27    :  
  28    :  // Expected page sizes and allocation granularities. Some usages of these are
  29    :  // at compile time, thus we need accessible constants.
  30  m :  static const size_t kUsualPageSize = 4096;
  31  m :  static const size_t kUsualAllocationGranularity = 64 * 1024;
  32    :  
  33    :  // The default sharding factor of the quarantine. This is used to give us linear
  34    :  // access for random removal and insertion of elements into the quarantine.
  35  m :  static const size_t kQuarantineDefaultShardingFactor = 128;
  36    :  
  37    :  // @returns the size of a page on the OS (usually 4KB).
  38    :  // @note Declaring this as a constant might result in an initialization order
  39    :  //     fiasco.
  40  m :  size_t GetPageSize();
  41    :  
  42    :  // @returns the allocation granularity of the OS (usually 64KB).
  43    :  // @note Declaring this as a constant might result in an initialization order
  44    :  //     fiasco.
  45  m :  size_t GetAllocationGranularity();
  46    :  
  47  m :  }  // namespace asan
  48  m :  }  // namespace agent
  49    :  
  50    :  #endif  // SYZYGY_AGENT_ASAN_CONSTANTS_H_