From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>, Scott Wood <oss@buserror.net>,
Hanjun Guo <hanjun.guo@linaro.org>,
Ding Tianhong <dingtianhong@huawei.com>,
dann frazier <dann.frazier@canonical.com>
Subject: Re: [PATCH v2 06/18] arm64: arch_timer: Add infrastructure for multiple erratum detection methods
Date: Wed, 22 Mar 2017 17:52:45 +0100 [thread overview]
Message-ID: <20170322165245.GG30499@mai> (raw)
In-Reply-To: <a922484a-1bb0-cfd0-1996-fab026a4feae@arm.com>
On Wed, Mar 22, 2017 at 03:59:21PM +0000, Marc Zyngier wrote:
> [Sorry, sent too quickly]
>
[ ... ]
> >> struct arch_timer_erratum_workaround {
> >> - const char *id; /* Indicate the Erratum ID */
> >> + enum arch_timer_erratum_match_type match_type;
> >
> > Putting the match_fn instead will be much more simpler and the code won't
> > have to deal with ate_match_type, no ?
>
> I'm not sure about the "much simpler" aspect. Each function is not
> necessarily standalone (see patches 8 and 13 for example, dealing with
> CPU-local defects).
Why not write always errata on a per cpu basis ? So there is no need to go
through global/local (at the timer level).
You have been probably looking at this much longer than me and perhaps I'm
missing something. However, I think we can find a way to simplify the approach.
Give me one day to see if I'm right.
> Also, given that we have two architectures to cater for, as well as two
> firmware interfaces, it makes more sense (at least to me) to have
> something that doesn't require to define a bunch of empty stubs (we
> already have too many of them) depending on arm vs arm64, DT vs ACPI,
> errata handling enabled vs disabled.
That is a fair point.
> We're sidestepping this at the moment because it all lives under one
> single config option that cannot be enabled from 32bit, but I hope to
> change that.
Ok, that sounds good.
Thanks for proposing something to deal elegantly with the errata.
-- Daniel
> > [ ... ]
> >
> >> +static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type type,
> >> + void *arg)
> >> +{
> >> + const struct arch_timer_erratum_workaround *wa;
> >> + ate_match_fn_t match_fn = NULL;
> >> +
> >> + if (static_branch_unlikely(&arch_timer_read_ool_enabled))
> >> + return;
> >> +
> >
> > Why is this check necessary ?
>
> We don't allow cumulative workarounds at this stage. This restriction
> gets lifted (to some extent) later in the series.
>
> Thanks,
>
> M.
> --
> Jazz is not dead. It just smells funny...
--
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next prev parent reply other threads:[~2017-03-22 17:01 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-20 17:48 [PATCH v2 00/18] clocksource/arch_timer: Errata workaround infrastructure rework Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 01/18] arm64: Allow checking of a CPU-local erratum Marc Zyngier
2017-03-22 9:22 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 02/18] arm64: Add CNTVCT_EL0 trap handler Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 03/18] arm64: Define Cortex-A73 MIDR Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 04/18] arm64: cpu_errata: Allow an erratum to be match for all revisions of a core Marc Zyngier
2017-03-22 14:57 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 05/18] arm64: cpu_errata: Add capability to advertise Cortex-A73 erratum 858921 Marc Zyngier
2017-03-22 15:01 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 06/18] arm64: arch_timer: Add infrastructure for multiple erratum detection methods Marc Zyngier
2017-03-22 15:41 ` Daniel Lezcano
2017-03-22 15:53 ` Marc Zyngier
2017-03-22 15:59 ` Marc Zyngier
2017-03-22 16:52 ` Daniel Lezcano [this message]
2017-03-23 17:30 ` Daniel Lezcano
2017-03-24 13:51 ` Marc Zyngier
2017-03-27 7:56 ` Daniel Lezcano
2017-03-28 13:07 ` Marc Zyngier
2017-03-28 13:34 ` Daniel Lezcano
2017-03-28 14:07 ` Marc Zyngier
2017-03-28 14:36 ` Daniel Lezcano
2017-03-28 14:48 ` Marc Zyngier
2017-03-28 14:55 ` Daniel Lezcano
2017-03-28 15:38 ` Marc Zyngier
2017-03-29 14:27 ` Daniel Lezcano
2017-03-29 14:56 ` Marc Zyngier
2017-03-29 15:12 ` Daniel Lezcano
2017-03-24 17:48 ` dann frazier
2017-03-24 18:00 ` Marc Zyngier
2017-03-30 9:28 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 07/18] arm64: arch_timer: Add erratum handler for globally defined capability Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 08/18] arm64: arch_timer: Add erratum handler for CPU-specific capability Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 09/18] arm64: arch_timer: Move arch_timer_reg_read/write around Marc Zyngier
2017-03-22 15:47 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 10/18] arm64: arch_timer: Get rid of erratum_workaround_set_sne Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 11/18] arm64: arch_timer: Rework the set_next_event workarounds Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 12/18] arm64: arch_timer: Make workaround methods optional Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 13/18] arm64: arch_timer: Allows a CPU-specific erratum to only affect a subset of CPUs Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 14/18] arm64: arch_timer: Move clocksource_counter and co around Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 15/18] arm64: arch_timer: Enable CNTVCT_EL0 trap if workaround is enabled Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 16/18] arm64: arch_timer: Workaround for Cortex-A73 erratum 858921 Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 17/18] arm64: arch_timer: Allow erratum matching with ACPI OEM information Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 18/18] arm64: arch_timer: Add HISILICON_ERRATUM_161010101 ACPI matching data Marc Zyngier
2017-03-22 13:56 ` [PATCH v2 00/18] clocksource/arch_timer: Errata workaround infrastructure rework Ding Tianhong
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