Re: [PATCH 06/17] arm64: arch_timer: Get rid of erratum_workaround_set_sne

[Mark Rutland]

On Mon, Mar 06, 2017 at 11:26:11AM +0000, Marc Zyngier wrote:
> Let's move the handling of workarounds affecting set_next_event
> to the affected function, instead of overwriding the pointers

Nit: overriding

> as an afterthough. Yes, this is an extra indirection on the
> erratum handling path, but the HW is busted anyway.

[...]

> +#define erratum_set_next_event_tval_virt(...)		({BUG_ON(1); 0;})
> +#define erratum_set_next_event_tval_phys(...)		({BUG_ON(1); 0;})

Nit: BUG()

[...]

>  {
> +	if (needs_unstable_timer_counter_workaround())
> +		return erratum_set_next_event_tval_virt(evt, clk);
> +
>  	set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
>  	return 0;
>  }
> @@ -487,6 +490,9 @@ static int arch_timer_set_next_event_virt(unsigned long evt,
>  static int arch_timer_set_next_event_phys(unsigned long evt,
>  					  struct clock_event_device *clk)
>  {
> +	if (needs_unstable_timer_counter_workaround())
> +		return erratum_set_next_event_tval_phys(evt, clk);
> +
>  	set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
>  	return 0;
>  }

I take it that the new conditionals are NOPs in the !erratum case, so
this doesn't adversely affect the usual case.

Thanks,
Mark.