linux-kernel - Re: [PATCH] clocksource: Fix arm_arch_timer clockmode when vDSO disabled

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Date:   Fri, 21 Feb 2020 16:33:03 +0000
From:   Vincenzo Frascino <vincenzo.frascino@....com>
To:     Marc Zyngier <maz@...nel.org>
Cc:     linux-arch@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, catalin.marinas@....com,
        will.deacon@....com, linux@...linux.org.uk, luto@...nel.org,
        tglx@...utronix.de, m.szyprowski@...sung.com, mark.rutland@....com
Subject: Re: [PATCH] clocksource: Fix arm_arch_timer clockmode when vDSO
 disabled

Hi Marc,

On 21/02/2020 16:24, Marc Zyngier wrote:
> On 2020-02-21 15:56, Vincenzo Frascino wrote:

[...]

> 
> Which is exactly the same thing as before. It's not an indirection,
> it is just another overloading of an existing symbol.
>

Yes, sorry, I missed the indirection here. I wanted more to agree on the concept.

>>> Fair enough. But don't override the symbol locally. Create a new one:
>>>
>>
>> I see what you mean now, you mean to not overload the semantical meaning of the
>> symbol. The symbol (VDSO_CLOCKMODE_ARCHTIMER) at this point is never defined
>> when VDSO=n, but I agree with you it can cause confusion.
> 
> Exactly. It breaks the expectation that if VDSO_CLOCKMODE_ARCHTIMER exists,
> it has a unique, known value. Yes, the outcome is the same. That doesn't
> make it acceptable though.
> 
> So building on your above example, here's what I'd like to see:
> 

[...]
All right, I agree, I will post the patches later on today.

-- 
Regards,
Vincenzo

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