linux-kernel - Re: [PATCH 1/2] clocksource: arm_arch_timer: Simplify and fix count reader code logic

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Message-ID: <267c5f9151c39fd2dcd0ce0b09d96545@kernel.org>
Date:   Mon, 17 Aug 2020 13:52:11 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Keqian Zhu <zhukeqian1@...wei.com>
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.cs.columbia.edu, kvm@...r.kernel.org,
        Steven Price <steven.price@....com>,
        Andrew Jones <drjones@...hat.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        wanghaibin.wang@...wei.com
Subject: Re: [PATCH 1/2] clocksource: arm_arch_timer: Simplify and fix count
 reader code logic

On 2020-08-17 13:24, Keqian Zhu wrote:
> In commit 0ea415390cd3 (clocksource/arm_arch_timer: Use 
> arch_timer_read_counter
> to access stable counters), we separate stable and normal count reader. 
> Actually
> the stable reader can correctly lead us to normal reader if we has no
> workaround.

Resulting in an unnecessary overhead on non-broken systems that can run
without CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND. Not happening.

> Besides, in erratum_set_next_event_tval_generic(), we use normal 
> reader, it is
> obviously wrong, so just revert this commit to solve this problem by 
> the way.

If you want to fix something, post a patch that does exactly that.

         M.
-- 
Jazz is not dead. It just smells funny...