Re: [PATCH 5/9] riscv: Fix set up of cpu hotplug callbacks

[Clément Léger]

On 07/02/2025 17:19, Andrew Jones wrote:
> CPU hotplug callbacks should be set up even if we detected all
> current cpus emulate misaligned accesses, since we want to
> ensure our expectations of all cpus emulating is maintained.
> 
> Fixes: 6e5ce7f2eae3 ("riscv: Decouple emulated unaligned accesses from access speed")
> Fixes: e7c9d66e313b ("RISC-V: Report vector unaligned access speed hwprobe")
> Signed-off-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
> ---
>  arch/riscv/kernel/unaligned_access_speed.c | 27 +++++++++++-----------
>  1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c
> index 780f1c5f512a..c9d3237649bb 100644
> --- a/arch/riscv/kernel/unaligned_access_speed.c
> +++ b/arch/riscv/kernel/unaligned_access_speed.c
> @@ -247,13 +247,6 @@ static void __init check_unaligned_access_speed_all_cpus(void)
>  	/* Check core 0. */
>  	smp_call_on_cpu(0, check_unaligned_access, bufs[0], true);
>  
> -	/*
> -	 * Setup hotplug callbacks for any new CPUs that come online or go
> -	 * offline.
> -	 */
> -	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "riscv:online",
> -				  riscv_online_cpu, riscv_offline_cpu);
> -
>  out:
>  	for_each_cpu(cpu, cpu_online_mask) {
>  		if (bufs[cpu])
> @@ -383,13 +376,6 @@ static int __init vec_check_unaligned_access_speed_all_cpus(void *unused __alway
>  {
>  	schedule_on_each_cpu(check_vector_unaligned_access);
>  
> -	/*
> -	 * Setup hotplug callbacks for any new CPUs that come online or go
> -	 * offline.
> -	 */
> -	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "riscv:online",
> -				  riscv_online_cpu_vec, NULL);
> -
>  	return 0;
>  }
>  #else /* CONFIG_RISCV_PROBE_VECTOR_UNALIGNED_ACCESS */
> @@ -415,6 +401,19 @@ static int __init check_unaligned_access_all_cpus(void)
>  			    NULL, "vec_check_unaligned_access_speed_all_cpus");
>  	}
>  
> +	/*
> +	 * Setup hotplug callbacks for any new CPUs that come online or go
> +	 * offline.
> +	 */
> +#ifdef CONFIG_RISCV_PROBE_UNALIGNED_ACCESS
> +	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "riscv:online",
> +				  riscv_online_cpu, riscv_offline_cpu);
> +#endif
> +#ifdef CONFIG_RISCV_PROBE_VECTOR_UNALIGNED_ACCESS
> +	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "riscv:online",
> +				  riscv_online_cpu_vec, NULL);
> +#endif
> +
>  	return 0;
>  }
>  

Hi Andrew,

Reviewed-by: Clément Léger <cleger@xxxxxxxxxxxx>

Thanks,

Clément