/* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2017 Linaro Ltd. <ard.biesheuvel@linaro.org> */ #ifndef __ASM_CPUFEATURE_H #define __ASM_CPUFEATURE_H #include <linux/log2.h> #include <asm/hwcap.h> /* * Due to the fact that ELF_HWCAP is a 32-bit type on ARM, and given the number * of optional CPU features it defines, ARM's CPU hardware capability bits have * been distributed over separate elf_hwcap and elf_hwcap2 variables, each of * which covers a subset of the available CPU features. * * Currently, only a few of those are suitable for automatic module loading * (which is the primary use case of this facility) and those happen to be all * covered by HWCAP2. So let's only cover those via the cpu_feature() * convenience macro for now (which is used by module_cpu_feature_match()). * However, all capabilities are exposed via the modalias, and can be matched * using an explicit MODULE_DEVICE_TABLE() that uses __hwcap_feature() directly. */ #define MAX_CPU_FEATURES 64 #define __hwcap_feature(x) ilog2(HWCAP_ ## x) #define __hwcap2_feature(x) (32 + ilog2(HWCAP2_ ## x)) #define cpu_feature(x) __hwcap2_feature(x) static inline bool cpu_have_feature(unsigned int num) { return num < 32 ? elf_hwcap & BIT(num) : elf_hwcap2 & BIT(num - 32); } #endif