linux-kernel - Re: [PATCH v3] arm64/arm: arm_pmuv3: perf: Don't truncate 64-bit registers

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Message-ID: <86jzqy1z1g.wl-maz@kernel.org>
Date:   Fri, 03 Nov 2023 18:18:03 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     Ilkka Koskinen <ilkka@...amperecomputing.com>,
        Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Zaid Al-Bassam <zalbassam@...gle.com>,
        Reiji Watanabe <reijiw@...gle.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Russell King <linux@...linux.org.uk>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] arm64/arm: arm_pmuv3: perf: Don't truncate 64-bit registers

On Fri, 03 Nov 2023 06:09:36 +0000,
Anshuman Khandual <anshuman.khandual@....com> wrote:
> 
> 
> 
> On 11/3/23 00:00, Ilkka Koskinen wrote:
> > The driver used to truncate several 64-bit registers such as PMCEID[n]
> > registers used to describe whether architectural and microarchitectural
> > events in range 0x4000-0x401f exist. Due to discarding the bits, the
> > driver made the events invisible, even if they existed.
> > 
> > Moreover, PMCCFILTR and PMCR registers have additional bits in the upper
> > 32 bits. This patch makes them available although they aren't currently
> > used. Finally, functions handling PMXEVCNTR and PMXEVTYPER registers are
> > removed as they not being used at all.
> > 
> > Fixes: df29ddf4f04b ("arm64: perf: Abstract system register accesses away")
> > Reported-by: Carl Worth <carl@...amperecomputing.com>
> 
> This needs an URL for the original bug report in the following format.
> 
>     Reported-by: Carl Worth <carl@...amperecomputing.com>
>     Closes: https://lore.kernel.org/..

A report is not necessarily done in a public list. And yet there is *a
lot* of value in recognising the reporter of the bug.

> 
> Otherwise, the following checkpatch warning shows up.
> 
> WARNING: Reported-by: should be immediately followed by Closes: with a URL to the report
> #17: 
> Reported-by: Carl Worth <carl@...amperecomputing.com>
> Signed-off-by: Ilkka Koskinen <ilkka@...amperecomputing.com>

Checkpatch can say what it wants, but that doesn't make it true.

	M.

-- 
Without deviation from the norm, progress is not possible.