diff options
| author | James Morse <james.morse@arm.com> | 2015-07-21 13:23:29 +0100 |
|---|---|---|
| committer | David Brown <david.brown@linaro.org> | 2015-12-03 16:53:51 -0800 |
| commit | 32bb76ad58ad061526a57d10f99912acd67aa894 (patch) | |
| tree | f63ca71eef7d03cec8ed21a7c82e5e4558ef40f0 | |
| parent | 9aaa9a81735a9a324dfd53d68532c9fa89aaf2af (diff) | |
arm64: kernel: Add min_field_value and use '>=' for feature detection
commit 18ffa046c509d0cd011eeea2c0418f2d014771fc upstream.
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>
Signed-off-by: David Brown <david.brown@linaro.org>
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 4 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 14 |
2 files changed, 13 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index c1044218a63a..ad54dbf6b5ea 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -41,8 +41,8 @@ struct arm64_cpu_capabilities { }; struct { /* Feature register checking */ - u64 register_mask; - u64 register_value; + int field_pos; + int min_field_value; }; }; }; diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 5ad86ceac010..7542a07a0a6d 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, }, {}, }; |