From 930da09f5e50dd22fb0a8600388da8677d62d671 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Fri, 14 Nov 2014 15:54:07 +0000 Subject: [PATCH] arm64: add cpu_capabilities bitmap For taking note if at least one CPU in the system needs a bug workaround or would benefit from a code optimization, we create a new bitmap to hold (artificial) feature bits. Since elf_hwcap is part of the userland ABI, we keep it alone and introduce a new data structure for that (along with some accessors). Signed-off-by: Andre Przywara Signed-off-by: Will Deacon --- arch/arm64/include/asm/cpufeature.h | 20 ++++++++++++++++++++ arch/arm64/kernel/setup.c | 3 +++ 2 files changed, 23 insertions(+) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index cd4ac0516488..20b2b3d6b702 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -21,9 +21,29 @@ #define MAX_CPU_FEATURES (8 * sizeof(elf_hwcap)) #define cpu_feature(x) ilog2(HWCAP_ ## x) +#define NCAPS 0 + +extern DECLARE_BITMAP(cpu_hwcaps, NCAPS); + static inline bool cpu_have_feature(unsigned int num) { return elf_hwcap & (1UL << num); } +static inline bool cpus_have_cap(unsigned int num) +{ + if (num >= NCAPS) + return false; + return test_bit(num, cpu_hwcaps); +} + +static inline void cpus_set_cap(unsigned int num) +{ + if (num >= NCAPS) + pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n", + num, NCAPS); + else + __set_bit(num, cpu_hwcaps); +} + #endif diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 2e17bd3806c8..c8629eb07ba6 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -50,6 +50,7 @@ #include #include #include +#include #include #include #include @@ -79,6 +80,8 @@ unsigned int compat_elf_hwcap __read_mostly = COMPAT_ELF_HWCAP_DEFAULT; unsigned int compat_elf_hwcap2 __read_mostly; #endif +DECLARE_BITMAP(cpu_hwcaps, NCAPS); + static const char *cpu_name; phys_addr_t __fdt_pointer __initdata; -- GitLab