Re: [PATCH v6 02/21] arm64: Allow mismatched 32-bit EL0 support

[Catalin Marinas]

On Tue, May 18, 2021 at 10:47:06AM +0100, Will Deacon wrote:
> +static int enable_mismatched_32bit_el0(unsigned int cpu)
> +{
> +	struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
> +	bool cpu_32bit = id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0);
> +
> +	if (cpu_32bit) {
> +		cpumask_set_cpu(cpu, cpu_32bit_el0_mask);
> +		static_branch_enable_cpuslocked(&arm64_mismatched_32bit_el0);

It may be worth only calling static_branch_enable_cpuslocked() if not
already set, in case you try this on a system with lots of CPUs.

-- 
Catalin