| /* | |
| * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com> | |
| * | |
| * This program is free software; you can redistribute it and/or | |
| * modify it under the terms of the GNU General Public License | |
| * as published by the Free Software Foundation; either version 2 | |
| * of the License, or (at your option) any later version. | |
| * | |
| * This program is distributed in the hope that it will be useful, | |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| * GNU General Public License for more details. | |
| * | |
| * You should have received a copy of the GNU General Public License | |
| * along with this program; if not, see <http://www.gnu.org/licenses/>. | |
| */ | |
| #ifndef _ORC_LOOKUP_H | |
| #define _ORC_LOOKUP_H | |
| /* | |
| * This is a lookup table for speeding up access to the .orc_unwind table. | |
| * Given an input address offset, the corresponding lookup table entry | |
| * specifies a subset of the .orc_unwind table to search. | |
| * | |
| * Each block represents the end of the previous range and the start of the | |
| * next range. An extra block is added to give the last range an end. | |
| * | |
| * The block size should be a power of 2 to avoid a costly 'div' instruction. | |
| * | |
| * A block size of 256 was chosen because it roughly doubles unwinder | |
| * performance while only adding ~5% to the ORC data footprint. | |
| */ | |
| #define LOOKUP_BLOCK_ORDER 8 | |
| #define LOOKUP_BLOCK_SIZE (1 << LOOKUP_BLOCK_ORDER) | |
| #ifndef LINKER_SCRIPT | |
| extern unsigned int orc_lookup[]; | |
| extern unsigned int orc_lookup_end[]; | |
| #define LOOKUP_START_IP (unsigned long)_stext | |
| #define LOOKUP_STOP_IP (unsigned long)_etext | |
| #endif /* LINKER_SCRIPT */ | |
| #endif /* _ORC_LOOKUP_H */ |