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author | 2014-03-04 01:10:04 +0000 | |
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committer | 2014-03-14 18:01:36 +0000 | |
commit | 3be1a5c4f75989cf457f13f38ff0913dff6d4996 (patch) | |
tree | 312f3bbfa0c6e783ea01078a701ce95667aabcbf /arch/arm64/include | |
parent | arm64: smp: make local symbol static (diff) | |
download | linux-3be1a5c4f75989cf457f13f38ff0913dff6d4996.tar.gz linux-3be1a5c4f75989cf457f13f38ff0913dff6d4996.tar.bz2 linux-3be1a5c4f75989cf457f13f38ff0913dff6d4996.zip |
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: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[catalin.marinas@arm.com: removed unnecessary "!!"]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include')
-rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 29 |
1 files changed, 29 insertions, 0 deletions
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. <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 |