Messages in this thread Patch in this message | | | From | Ard Biesheuvel <> | Subject | [PATCH 4/5] arm64: enable generic CPU feature modalias matching for this arch | Date | Wed, 29 Jan 2014 17:50:45 +0100 |
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This enables support for the generic CPU feature modalias implementation that wires up optional CPU features to udev based module autoprobing.
A file <asm/cpufeatures.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: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/cpufeature.h | 30 ++++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) create mode 100644 arch/arm64/include/asm/cpufeature.h
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index dd4327f09ba4..e339099b6fbd 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -16,6 +16,7 @@ config ARM64 select DCACHE_WORD_ACCESS select GENERIC_CLOCKEVENTS select GENERIC_CLOCKEVENTS_BROADCAST if SMP + select GENERIC_CPU_AUTOPROBE select GENERIC_IOMAP select GENERIC_IRQ_PROBE select GENERIC_IRQ_SHOW diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h new file mode 100644 index 000000000000..1d902efa201d --- /dev/null +++ b/arch/arm64/include/asm/cpufeature.h @@ -0,0 +1,30 @@ +/* + * 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/elf.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 sizeof(elf_hwcap) +#define cpu_feature(x) ((unsigned int)ilog2(HWCAP_ ## x)) + +static inline bool cpu_have_feature(unsigned int num) +{ + return !!(elf_hwcap & (1 << num)); +} + +#endif -- 1.8.3.2
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