mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-27 01:41:30 +07:00
ea2d9a96b6
Wire up the generic support for exposing CPU feature bits via the modalias in /sys/device/system/cpu. This allows udev to automatically load modules for things like crypto algorithms that are implemented using optional instructions. Since it is non-trivial to transparantly support both HWCAP and HWCAP2 capabilities in the cpu_feature() macro (which allows a module's hwcap dependency and init routine to be declared using a single invocation of module_cpu_feature_match()), support only HWCAP2 for now, which covers the capabilities that are most likely to be useful in this manner. Module dependencies on HWCAP will need to be declared explicitly via a MODULE_DEVICE_TABLE(cpu, ...) declaration. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
39 lines
1.4 KiB
C
39 lines
1.4 KiB
C
/*
|
|
* Copyright (C) 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#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
|