[PATCH v4 08/41] arm64: mpam: Add cpu_pm notifier to restore MPAM sysregs

Catalin Marinas catalin.marinas at arm.com
Thu Feb 5 08:54:22 PST 2026


On Tue, Feb 03, 2026 at 09:43:09PM +0000, Ben Horgan wrote:
> From: James Morse <james.morse at 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.
> 
> Tested-by: Gavin Shan <gshan at redhat.com>
> Tested-by: Shaopeng Tan <tan.shaopeng at jp.fujitsu.com>
> Tested-by: Peter Newman <peternewman at google.com>
> Reviewed-by: Jonathan Cameron <jonathan.cameron at huawei.com>
> Reviewed-by: Gavin Shan <gshan at redhat.com>
> Signed-off-by: James Morse <james.morse at arm.com>
> Signed-off-by: Ben Horgan <ben.horgan at arm.com>

Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>



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