1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #pragma once 18 19 #define NS_PER_S 1'000'000'000LL 20 21 // Size of the shadow call stack. This can be small because these stacks only 22 // contain return addresses. This must be a power of 2 so the mask trick works. 23 // See the SCS commentary in pthread_internal.h for more detail. 24 // SCS_SIZE must be a multiple of page size. 25 // We used 8KiB until V but switched to 16KiB in V to experiment with 16KiB pages. 26 #define SCS_SIZE (16 * 1024) 27 #define SCS_MASK (SCS_SIZE - 1) 28 29 // The shadow call stack is allocated at an aligned address within a guard region of this size. The 30 // guard region must be large enough that we can allocate an SCS_SIZE-aligned SCS while ensuring 31 // that there is at least one guard page after the SCS so that a stack overflow results in a SIGSEGV 32 // instead of corrupting the allocation that comes after it. 33 #define SCS_GUARD_REGION_SIZE (16 * 1024 * 1024) 34