1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
4 */
5#ifndef _ORC_LOOKUP_H
6#define _ORC_LOOKUP_H
7
8/*
9 * This is a lookup table for speeding up access to the .orc_unwind table.
10 * Given an input address offset, the corresponding lookup table entry
11 * specifies a subset of the .orc_unwind table to search.
12 *
13 * Each block represents the end of the previous range and the start of the
14 * next range. An extra block is added to give the last range an end.
15 *
16 * The block size should be a power of 2 to avoid a costly 'div' instruction.
17 *
18 * A block size of 256 was chosen because it roughly doubles unwinder
19 * performance while only adding ~5% to the ORC data footprint.
20 */
21#define LOOKUP_BLOCK_ORDER 8
22#define LOOKUP_BLOCK_SIZE (1 << LOOKUP_BLOCK_ORDER)
23
24#ifndef LINKER_SCRIPT
25
26extern unsigned int orc_lookup[];
27extern unsigned int orc_lookup_end[];
28
29#define LOOKUP_START_IP (unsigned long)_stext
30#define LOOKUP_STOP_IP (unsigned long)_etext
31
32#endif /* LINKER_SCRIPT */
33
34#endif /* _ORC_LOOKUP_H */
35