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| author | Andre Przywara <andre.przywara@arm.com> | 2014-11-14 18:54:07 +0300 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2014-11-25 16:22:37 +0300 |
| commit | 930da09f5e50dd22fb0a8600388da8677d62d671 (patch) | |
| tree | c2cfac924f9513700dad6bffdda1b8838b73b145 /arch/arm64 | |
| parent | 909633957d85561dab7655d69a9d17dd16231d92 (diff) | |
| download | linux-930da09f5e50dd22fb0a8600388da8677d62d671.tar.xz | |
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 <andre.przywara@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 20 | ||||
| -rw-r--r-- | arch/arm64/kernel/setup.c | 3 |
2 files changed, 23 insertions, 0 deletions
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 <asm/cputype.h> #include <asm/elf.h> #include <asm/cputable.h> +#include <asm/cpufeature.h> #include <asm/cpu_ops.h> #include <asm/sections.h> #include <asm/setup.h> @@ -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; |