[PATCH v7 1/4] arm64: cpufeature: Introduce MATCH_ALL_EARLY_CPUS capability type

Suzuki K Poulose suzuki.poulose at arm.com
Tue Jun 17 03:20:32 PDT 2025


On 17/06/2025 10:51, Mikołaj Lenczewski wrote:
> From: Catalin Marinas <catalin.marinas at arm.com>
> 
> For system-wide capabilities, the kernel has the SCOPE_SYSTEM type. Such
> capabilities are checked once the SMP boot has completed using the
> sanitised ID registers. However, there is a need for a new capability
> type similar in scope to the system one but with checking performed
> locally on each CPU during boot (e.g. based on MIDR_EL1 which is not a
> sanitised register).
> 
> Introduce ARM64_CPUCAP_MATCH_ALL_EARLY_CPUS which, together with
> ARM64_CPUCAP_SCOPE_LOCAL_CPU, ensures that such capability is enabled
> only if all early CPUs have it. For ease of use, define
> ARM64_CPUCAP_EARLY_LOCAL_CPU_FEATURE which combines SCOPE_LOCAL_CPU,
> PERMITTED_FOR_LATE_CPUS and MATCH_ALL_EARLY_CPUS.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
> Signed-off-by: Mikołaj Lenczewski <miko.lenczewski at arm.com>
> Cc: Suzuki K Poulose <Suzuki.Poulose at arm.com>
> ---

Reviewed-by: Suzuki K Poulose <suzuki.poulose at arm.com>




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