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Commit 3be1a5c4 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Catalin Marinas
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arm64: enable generic CPU feature modalias matching for this architecture 



This enables support for the generic CPU feature modalias implementation that
wires up optional CPU features to udev based module autoprobing.

A file <asm/cpufeature.h> is provided that maps CPU feature numbers to
elf_hwcap bits, which is the standard way on arm64 to advertise optional CPU
features both internally and to user space.

Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
[catalin.marinas@arm.com: removed unnecessary "!!"]
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 7184659b

arch/arm64/Kconfig

+1 −0
Original line number Original line Diff line number Diff line
@@ -16,6 +16,7 @@ config ARM64 
	select DCACHE_WORD_ACCESS

	select DCACHE_WORD_ACCESS

	select GENERIC_CLOCKEVENTS

	select GENERIC_CLOCKEVENTS

	select GENERIC_CLOCKEVENTS_BROADCAST if SMP

	select GENERIC_CLOCKEVENTS_BROADCAST if SMP

	select GENERIC_CPU_AUTOPROBE

	select GENERIC_IOMAP

	select GENERIC_IOMAP

	select GENERIC_IRQ_PROBE

	select GENERIC_IRQ_PROBE

	select GENERIC_IRQ_SHOW

	select GENERIC_IRQ_SHOW

arch/arm64/include/asm/cpufeature.h

0 → 100644
+29 −0
Original line number Original line Diff line number Diff line 
/*

 * Copyright (C) 2014 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 <asm/hwcap.h>



/*

 * In the arm64 world (as in the ARM world), elf_hwcap is used both internally

 * in the kernel and for user space to keep track of which optional features

 * are supported by the current system. So let's map feature 'x' to HWCAP_x.

 * Note that HWCAP_x constants are bit fields so we need to take the log.

 */



#define MAX_CPU_FEATURES	(8 * sizeof(elf_hwcap))

#define cpu_feature(x)		ilog2(HWCAP_ ## x)



static inline bool cpu_have_feature(unsigned int num)

{

	return elf_hwcap & (1UL << num);

}



#endif