[PATCH 07/33] arm64: kconfig: Add Kconfig entry for MPAM

[Ben Horgan]

Hi James,

On 8/22/25 16:29, James Morse wrote:
> The bulk of the MPAM driver lives outside the arch code because it
> largely manages MMIO devices that generate interrupts. The driver
> needs a Kconfig symbol to enable it, as MPAM is only found on arm64
> platforms, that is where the Kconfig option makes the most sense.
> 
> This Kconfig option will later be used by the arch code to enable
> or disable the MPAM context-switch code, and registering the CPUs
> properties with the MPAM driver.
> 
> Signed-off-by: James Morse <james.morse at arm.com>
> Reviewed-by: Jonathan Cameron <jonathan.cameron at huawei.com>
> ---
>  arch/arm64/Kconfig | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index e9bbfacc35a6..658e47fc0c5a 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -2060,6 +2060,23 @@ config ARM64_TLB_RANGE
>  	  ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
>  	  range of input addresses.
>  
> +config ARM64_MPAM
> +	bool "Enable support for MPAM"
> +	help
> +	  Memory Partitioning and Monitoring is an optional extension
> +	  that allows the CPUs to mark load and store transactions with
> +	  labels for partition-id and performance-monitoring-group.
> +	  System components, such as the caches, can use the partition-id
> +	  to apply a performance policy. MPAM monitors can use the
> +	  partition-id and performance-monitoring-group to measure the
> +	  cache occupancy or data throughput.
> +
> +	  Use of this extension requires CPU support, support in the
> +	  memory system components (MSC), and a description from firmware
> +	  of where the MSC are in the address space.
> +
> +	  MPAM is exposed to user-space via the resctrl pseudo filesystem.
> +
>  endmenu # "ARMv8.4 architectural features"

Should this be moved to "ARMv8.2 architectural features" rather than the
8.4 menu? In the arm reference manual, version L.b, I see FEAT_MPAM
listed in the section A2.2.3.1 Features added to the Armv8.2 extension
in later releases.

>  
>  menu "ARMv8.5 architectural features"

Thanks,

Ben