Re: [PATCH v2 10/45] arm64: mpam: Add cpu_pm notifier to restore MPAM sysregs

Jonathan Cameron
2026-01-05T17:10:06Z

On Fri, 19 Dec 2025 18:11:12 +0000
Ben Horgan <ben.horgan@arm.com> wrote:

> From: James Morse <james.morse@arm.com>
>
> The MPAM system registers will be lost if the CPU is reset during PSCI's
> CPU_SUSPEND.
>
> Add a PM notifier to restore them.
>
> mpam_thread_switch(current) can't be used as this won't make any changes if
> the in-memory copy says the register already has the correct value. In
> reality the system register is UNKNOWN out of reset.
>
> Signed-off-by: James Morse <james.morse@arm.com>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>