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