Re: [PATCH 2/8] IRQ: generalize [gs]et_irq_regs()

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 11/01/2024 07:32, Jan Beulich wrote:
> Move functions (and their data) to common code, and invoke the functions
> on Arm as well. This is in preparation of dropping the register
> parameters from handler functions.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>

> ---
> To limit visibility of the per-CPU data item, we may want to consider
> making the functions out-of-line ones (in common/irq.c).
>
> --- a/xen/arch/arm/irq.c
> +++ b/xen/arch/arm/irq.c
> @@ -221,6 +221,7 @@ void do_IRQ(struct cpu_user_regs *regs,
>   {
>       struct irq_desc *desc = irq_to_desc(irq);
>       struct irqaction *action;
> +    struct cpu_user_regs *old_regs = set_irq_regs(regs);
>   
>       perfc_incr(irqs);
>   
> @@ -288,6 +289,7 @@ out:
>   out_no_end:
>       spin_unlock(&desc->lock);
>       irq_exit();
> +    set_irq_regs(old_regs);
>   }
[...]

> +/*
> + * Per-cpu interrupted context register state - the top-most interrupt frame
> + * on the stack.
> + */
> +DECLARE_PER_CPU(struct cpu_user_regs *, irq_regs);
> +
> +static inline struct cpu_user_regs *get_irq_regs(void)
> +{
> +       return this_cpu(irq_regs);
> +}
> +
> +static inline struct cpu_user_regs *set_irq_regs(struct cpu_user_regs 
> *new_regs)
> +{
> +       struct cpu_user_regs *old_regs, **pp_regs = &this_cpu(irq_regs);
> +
> +       old_regs = *pp_regs;
> +       *pp_regs = new_regs;
NIT: As you move the code, can you add a newline before the return?

> +       return old_regs;
> +}
> +
>   struct domain;
>   struct vcpu;
Cheers,

--
Julien Grall