| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 Linaro Ltd. <ard.biesheuvel@linaro.org> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 as |
| 6 | * published by the Free Software Foundation. |
| 7 | */ |
| 8 | |
| 9 | #ifndef __ASM_CPUFEATURE_H |
| 10 | #define __ASM_CPUFEATURE_H |
| 11 | |
| 12 | #include <linux/log2.h> |
| 13 | #include <asm/hwcap.h> |
| 14 | |
| 15 | /* |
| 16 | * Due to the fact that ELF_HWCAP is a 32-bit type on ARM, and given the number |
| 17 | * of optional CPU features it defines, ARM's CPU hardware capability bits have |
| 18 | * been distributed over separate elf_hwcap and elf_hwcap2 variables, each of |
| 19 | * which covers a subset of the available CPU features. |
| 20 | * |
| 21 | * Currently, only a few of those are suitable for automatic module loading |
| 22 | * (which is the primary use case of this facility) and those happen to be all |
| 23 | * covered by HWCAP2. So let's only cover those via the cpu_feature() |
| 24 | * convenience macro for now (which is used by module_cpu_feature_match()). |
| 25 | * However, all capabilities are exposed via the modalias, and can be matched |
| 26 | * using an explicit MODULE_DEVICE_TABLE() that uses __hwcap_feature() directly. |
| 27 | */ |
| 28 | #define MAX_CPU_FEATURES 64 |
| 29 | #define __hwcap_feature(x) ilog2(HWCAP_ ## x) |
| 30 | #define __hwcap2_feature(x) (32 + ilog2(HWCAP2_ ## x)) |
| 31 | #define cpu_feature(x) __hwcap2_feature(x) |
| 32 | |
| 33 | static inline bool cpu_have_feature(unsigned int num) |
| 34 | { |
| 35 | return num < 32 ? elf_hwcap & BIT(num) : elf_hwcap2 & BIT(num - 32); |
| 36 | } |
| 37 | |
| 38 | #endif |