Re: [PATCH v3 09/47] arm64: mpam: Add cpu_pm notifier to restore MPAM sysregs

From: Gavin Shan

Date: Mon Jan 19 2026 - 01:41:16 EST


On 1/13/26 12:58 AM, Ben Horgan wrote:
From: James Morse <james.morse@xxxxxxx>

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.

Reviewed-by: Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Ben Horgan <ben.horgan@xxxxxxx>
---
arch/arm64/kernel/mpam.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)


Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>