[PATCH 09/16] arm64: capabilities: Introduce strict features based on local CPU
From: suzuki.poulose@arm.com (Suzuki K Poulose)
Date: 2018-01-23 12:30:22
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Add type for features that are detected on individual CPUs, rather than on a system wide safe features. This behavior is similar to that of a strict cpu erratum, where a later CPU is not allowed to boot if the system doesn't posses it. Use this for software prefetching capability. Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- arch/arm64/include/asm/cpufeature.h | 7 +++++++ arch/arm64/kernel/cpufeature.c | 2 +- 2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index a621d2184227..4c3d6987acfc 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h@@ -118,6 +118,13 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; */ #define ARM64_CPUCAP_BOOT_SYSTEM_FEATURE \ (ARM64_CPUCAP_SCOPE_SYSTEM | ARM64_CPUCAP_LATE_CPU_SAFE_TO_HAVE) +/* + * CPU feature detected at boot time based on feature of one or more CPUs. + * It is not safe for a late CPU to have this feature, when the system doesn't + * have it. But it is safe to miss the feature if the system has it. + */ +#define ARM64_CPUCAP_STRICT_CPU_LOCAL_FEATURE \ + (ARM64_CPUCAP_SCOPE_LOCAL_CPU | ARM64_CPUCAP_LATE_CPU_SAFE_TO_MISS) struct arm64_cpu_capabilities { const char *desc;
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 7ae5cf9092d0..111f6c4b4cd7 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c@@ -951,7 +951,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "Software prefetching using PRFM", .capability = ARM64_HAS_NO_HW_PREFETCH, - .type = ARM64_CPUCAP_BOOT_SYSTEM_FEATURE, + .type = ARM64_CPUCAP_STRICT_CPU_LOCAL_FEATURE, .matches = has_no_hw_prefetch, }, #ifdef CONFIG_ARM64_UAO
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2.13.6