Current File : //usr/src/linux-headers-5.15.0-125-generic/arch/arm/include/asm/cpufeature.h
/* 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
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