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1ccea77e | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
ee9f8fce JP |
2 | /* |
3 | * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com> | |
ee9f8fce JP |
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 | ||
26 | extern unsigned int orc_lookup[]; | |
27 | extern 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 */ |