1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 #ifndef _ORC_LOOKUP_H 3 #define _ORC_LOOKUP_H 4 5 /* 6 * This is a lookup table for speeding up access to the .orc_unwind table. 7 * Given an input address offset, the corresponding lookup table entry 8 * specifies a subset of the .orc_unwind table to search. 9 * 10 * Each block represents the end of the previous range and the start of the 11 * next range. An extra block is added to give the last range an end. 12 * 13 * The block size should be a power of 2 to avoid a costly 'div' instruction. 14 * 15 * A block size of 256 was chosen because it roughly doubles unwinder 16 * performance while only adding ~5% to the ORC data footprint. 17 */ 18 #define LOOKUP_BLOCK_ORDER 8 19 #define LOOKUP_BLOCK_SIZE (1 << LOOKUP_BLOCK_ORDER) 20 21 #ifndef LINKER_SCRIPT 22 23 extern unsigned int orc_lookup[]; 24 extern unsigned int orc_lookup_end[]; 25 26 #define LOOKUP_START_IP (unsigned long)_stext 27 #define LOOKUP_STOP_IP (unsigned long)_etext 28 29 #endif /* LINKER_SCRIPT */ 30 31 #endif /* _ORC_LOOKUP_H */ 32