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d2912cb1 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
ea2d9a96 AB |
2 | /* |
3 | * Copyright (C) 2017 Linaro Ltd. <ard.biesheuvel@linaro.org> | |
ea2d9a96 AB |
4 | */ |
5 | ||
6 | #ifndef __ASM_CPUFEATURE_H | |
7 | #define __ASM_CPUFEATURE_H | |
8 | ||
9 | #include <linux/log2.h> | |
10 | #include <asm/hwcap.h> | |
11 | ||
12 | /* | |
13 | * Due to the fact that ELF_HWCAP is a 32-bit type on ARM, and given the number | |
14 | * of optional CPU features it defines, ARM's CPU hardware capability bits have | |
15 | * been distributed over separate elf_hwcap and elf_hwcap2 variables, each of | |
16 | * which covers a subset of the available CPU features. | |
17 | * | |
18 | * Currently, only a few of those are suitable for automatic module loading | |
19 | * (which is the primary use case of this facility) and those happen to be all | |
20 | * covered by HWCAP2. So let's only cover those via the cpu_feature() | |
21 | * convenience macro for now (which is used by module_cpu_feature_match()). | |
22 | * However, all capabilities are exposed via the modalias, and can be matched | |
23 | * using an explicit MODULE_DEVICE_TABLE() that uses __hwcap_feature() directly. | |
24 | */ | |
25 | #define MAX_CPU_FEATURES 64 | |
26 | #define __hwcap_feature(x) ilog2(HWCAP_ ## x) | |
27 | #define __hwcap2_feature(x) (32 + ilog2(HWCAP2_ ## x)) | |
28 | #define cpu_feature(x) __hwcap2_feature(x) | |
29 | ||
30 | static inline bool cpu_have_feature(unsigned int num) | |
31 | { | |
32 | return num < 32 ? elf_hwcap & BIT(num) : elf_hwcap2 & BIT(num - 32); | |
33 | } | |
34 | ||
35 | #endif |