From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Wed, 29 Jan 2014 17:50:45 +0100 Subject: [PATCH 4/5] arm64: enable generic CPU feature modalias matching for this arch In-Reply-To: <1391014246-9715-1-git-send-email-ard.biesheuvel@linaro.org> References: <1391014246-9715-1-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <1391014246-9715-5-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This enables support for the generic CPU feature modalias implementation that wires up optional CPU features to udev based module autoprobing. A file 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 --- 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. + * + * 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 +#include + +/* + * 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