linux-kernel - Re: [RFC PATCH 28/38] arm64: mpam: Select ARCH_HAS_CPU

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4e491c89-a63d-4c13-a0f4-9883a6bc6407@arm.com>
Date: Tue, 9 Dec 2025 16:33:11 +0000
From: Ben Horgan <ben.horgan@....com>
To: James Morse <james.morse@....com>, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org
Cc: D Scott Phillips OS <scott@...amperecomputing.com>,
 carl@...amperecomputing.com, lcherian@...vell.com,
 bobo.shaobowang@...wei.com, tan.shaopeng@...itsu.com,
 baolin.wang@...ux.alibaba.com, Jamie Iles <quic_jiles@...cinc.com>,
 Xin Hao <xhao@...ux.alibaba.com>, peternewman@...gle.com,
 dfustini@...libre.com, amitsinght@...vell.com,
 David Hildenbrand <david@...nel.org>, Dave Martin <dave.martin@....com>,
 Koba Ko <kobak@...dia.com>, Shanker Donthineni <sdonthineni@...dia.com>,
 fenghuay@...dia.com, baisheng.gao@...soc.com,
 Jonathan Cameron <jonathan.cameron@...wei.com>, Gavin Shan
 <gshan@...hat.com>, rohit.mathew@....com, reinette.chatre@...el.com,
 Punit Agrawal <punit.agrawal@....qualcomm.com>
Subject: Re: [RFC PATCH 28/38] arm64: mpam: Select ARCH_HAS_CPU_RESCTRL

Hi James,

On 12/5/25 21:58, James Morse wrote:
> Enough MPAM support is present to enable ARCH_HAS_CPU_RESCTRL.
> Let it rip^Wlink!
> 
> ARCH_HAS_CPU_RESCTRL indicates resctrl can be enabled. It is enabled
> by the arch code sipmly because it has 'arch' in its name.
> 
> This removes ARM_CPU_RESCTRL as a mimic of X86_CPU_RESCTRL.
> While here, move the ACPI dependency to the driver's Kconfig file.

Mention we're know longer hiding behind CONFIG_EXPERT.

> 
> Signed-off-by: James Morse <james.morse@....com>
> ---
>  arch/arm64/Kconfig               | 4 ++--
>  arch/arm64/include/asm/resctrl.h | 2 ++
>  drivers/resctrl/Kconfig          | 9 ++++++++-
>  drivers/resctrl/Makefile         | 2 +-
>  4 files changed, 13 insertions(+), 4 deletions(-)
>  create mode 100644 arch/arm64/include/asm/resctrl.h
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 558baa9e7c08..e67885ac7717 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -2025,8 +2025,8 @@ config ARM64_TLB_RANGE
>  
>  config ARM64_MPAM
>  	bool "Enable support for MPAM"
> -	select ARM64_MPAM_DRIVER if EXPERT	# does nothing yet
> -	select ACPI_MPAM if ACPI
> +	select ARM64_MPAM_DRIVER
> +	select ARCH_HAS_CPU_RESCTRL
>  	help
>  	  Memory System Resource Partitioning and Monitoring (MPAM) is an
>  	  optional extension to the Arm architecture that allows each
> diff --git a/arch/arm64/include/asm/resctrl.h b/arch/arm64/include/asm/resctrl.h
> new file mode 100644
> index 000000000000..b506e95cf6e3
> --- /dev/null
> +++ b/arch/arm64/include/asm/resctrl.h
> @@ -0,0 +1,2 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#include <linux/arm_mpam.h>
> diff --git a/drivers/resctrl/Kconfig b/drivers/resctrl/Kconfig
> index c808e0470394..672abea3b03c 100644
> --- a/drivers/resctrl/Kconfig
> +++ b/drivers/resctrl/Kconfig
> @@ -1,6 +1,7 @@
>  menuconfig ARM64_MPAM_DRIVER
>  	bool "MPAM driver"
> -	depends on ARM64 && ARM64_MPAM && EXPERT
> +	depends on ARM64 && ARM64_MPAM
> +	select ACPI_MPAM if ACPI
>  	help
>  	  Memory System Resource Partitioning and Monitoring (MPAM) driver for
>  	  System IP, e.g. caches and memory controllers.
> @@ -22,3 +23,9 @@ config MPAM_KUNIT_TEST
>  	  If unsure, say N.
>  
>  endif
> +
> +config ARM64_MPAM_RESCTRL_FS
> +	bool
> +	default y if ARM64_MPAM_DRIVER && RESCTRL_FS
> +	select RESCTRL_RMID_DEPENDS_ON_CLOSID
> +	select RESCTRL_ASSIGN_FIXED
> diff --git a/drivers/resctrl/Makefile b/drivers/resctrl/Makefile
> index 40beaf999582..4f6d0e81f9b8 100644
> --- a/drivers/resctrl/Makefile
> +++ b/drivers/resctrl/Makefile
> @@ -1,5 +1,5 @@
>  obj-$(CONFIG_ARM64_MPAM_DRIVER)			+= mpam.o
>  mpam-y						+= mpam_devices.o
> -mpam-$(CONFIG_ARM_CPU_RESCTRL)			+= mpam_resctrl.o
> +mpam-$(CONFIG_ARM64_MPAM_RESCTRL_FS)		+= mpam_resctrl.o
>  
>  ccflags-$(CONFIG_ARM64_MPAM_DRIVER_DEBUG)	+= -DDEBUG

Thanks,

Ben