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Date: Mon, 20 Mar 2017 14:06:18 +0000
From: Mark Rutland <mark.rutland@arm.com>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Scott Wood <oss@buserror.net>, Will Deacon <will.deacon@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Hanjun Guo <hanjun.guo@linaro.org>,
        Ding Tianhong <dingtianhong@huawei.com>
Subject: Re: [PATCH 06/17] arm64: arch_timer: Get rid of
 erratum_workaround_set_sne
Message-ID: <20170320140618.GF31213@leverpostej>
References: <20170306112622.13853-1-marc.zyngier@arm.com>
 <20170306112622.13853-7-marc.zyngier@arm.com>
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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.