Re: [PATCH v3 5/8] riscv: smp: use NMI for CPU stop

[Radim Krčmář]

2025-11-27T20:53:02+08:00, Yunhui Cui <cuiyunhui@xxxxxxxxxxxxx>:
> Use NMI instead of IPI for CPU stop if RISC-V SSE NMI is supported.
>
> Signed-off-by: Yunhui Cui <cuiyunhui@xxxxxxxxxxxxx>
> ---
> diff --git a/drivers/firmware/riscv/riscv_sse_nmi.c b/drivers/firmware/riscv/riscv_sse_nmi.c
> @@ -58,6 +58,7 @@ static int local_nmi_handler(u32 evt, void *arg, struct pt_regs *regs)
>  	type = atomic_read(this_cpu_ptr(&local_nmi));
>  
>  	NMI_HANDLE(LOCAL_NMI_CRASH, cpu_crash_stop, cpu, regs);
> +	NMI_HANDLE(LOCAL_NMI_STOP, cpu_stop);

Please document the intended preemption design for all SSE events,
because it will be a nightmare if we forget some assumptions in the
coming years.  (That includes the relative priorities of RAS/PMU/...)

Thanks.