From 3be1a5c4f75989cf457f13f38ff0913dff6d4996 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 4 Mar 2014 01:10:04 +0000 Subject: [PATCH] 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 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 [catalin.marinas@arm.com: removed unnecessary "!!"] Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/cpufeature.h | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+) create mode 100644 arch/arm64/include/asm/cpufeature.h diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 507ab6e53522..8cabe36e285c 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..cd4ac0516488 --- /dev/null +++ b/arch/arm64/include/asm/cpufeature.h @@ -0,0 +1,29 @@ +/* + * 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 + +/* + * 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 -- 2.20.1