1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
4 * Copyright (C) 2020 Loongson Technology Co., Ltd.
5 */
6#ifndef _ASM_ORC_LOOKUP_H
7#define _ASM_ORC_LOOKUP_H
8
9/*
10 * This is a lookup table for speeding up access to the .orc_unwind table.
11 * Given an input address offset, the corresponding lookup table entry
12 * specifies a subset of the .orc_unwind table to search.
13 *
14 * Each block represents the end of the previous range and the start of the
15 * next range.  An extra block is added to give the last range an end.
16 *
17 * The block size should be a power of 2 to avoid a costly 'div' instruction.
18 *
19 * A block size of 256 was chosen because it roughly doubles unwinder
20 * performance while only adding ~5% to the ORC data footprint.
21 */
22#define LOOKUP_BLOCK_ORDER	8
23#define LOOKUP_BLOCK_SIZE	(1 << LOOKUP_BLOCK_ORDER)
24
25#ifndef LINKER_SCRIPT
26
27extern unsigned int orc_lookup[];
28extern unsigned int orc_lookup_end[];
29
30#define LOOKUP_START_IP		((unsigned long)_stext)
31#define LOOKUP_STOP_IP		((unsigned long)_etext)
32
33#endif /* LINKER_SCRIPT */
34
35#endif /* _ASM_ORC_LOOKUP_H */
36