diff options
author | James Morse <james.morse@arm.com> | 2015-07-21 14:23:29 +0200 |
---|---|---|
committer | Will Deacon <will.deacon@arm.com> | 2015-07-27 12:08:41 +0200 |
commit | 18ffa046c509d0cd011eeea2c0418f2d014771fc (patch) | |
tree | f227a03aa45ce8a70c61b54e9bbf691ee5736855 /arch/arm64/kernel/cpufeature.c | |
parent | arm64: kernel: Add cpufeature 'enable' callback (diff) | |
download | linux-18ffa046c509d0cd011eeea2c0418f2d014771fc.tar.xz linux-18ffa046c509d0cd011eeea2c0418f2d014771fc.zip |
arm64: kernel: Add min_field_value and use '>=' for feature detection
When a new cpu feature is available, the cpu feature bits will have some
initial value, which is incremented when the feature is updated.
This patch changes 'register_value' to be 'min_field_value', and checks
the feature bits value (interpreted as a signed int) is greater than this
minimum.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to '')
-rw-r--r-- | arch/arm64/kernel/cpufeature.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 650ffc28bedc..74fd0f74b065 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -23,12 +23,20 @@ #include <asm/cpufeature.h> static bool +feature_matches(u64 reg, const struct arm64_cpu_capabilities *entry) +{ + int val = cpuid_feature_extract_field(reg, entry->field_pos); + + return val >= entry->min_field_value; +} + +static bool has_id_aa64pfr0_feature(const struct arm64_cpu_capabilities *entry) { u64 val; val = read_cpuid(id_aa64pfr0_el1); - return (val & entry->register_mask) == entry->register_value; + return feature_matches(val, entry); } static const struct arm64_cpu_capabilities arm64_features[] = { @@ -36,8 +44,8 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .desc = "GIC system register CPU interface", .capability = ARM64_HAS_SYSREG_GIC_CPUIF, .matches = has_id_aa64pfr0_feature, - .register_mask = (0xf << 24), - .register_value = (1 << 24), + .field_pos = 24, + .min_field_value = 1, }, {}, }; |