Re: [PATCH] arm64: cpufeature: Enable Qualcomm erratas

From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	stable@vger.kernel.org, Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH] arm64: cpufeature: Enable Qualcomm erratas
Date: Tue, 29 Oct 2019 10:03:57 -0700	[thread overview]
Message-ID: <20191029170357.GW571@minitux> (raw)
In-Reply-To: <20191029113956.GC12103@willie-the-truck>

On Tue 29 Oct 04:39 PDT 2019, Will Deacon wrote:

> On Mon, Oct 28, 2019 at 11:04:32PM -0700, Bjorn Andersson wrote:
> > With the introduction of 'cce360b54ce6 ("arm64: capabilities: Filter the
> > entries based on a given mask")' the Qualcomm erratas are no long
> > applied.
> > 
> > The result of not applying errata 1003 is that MSM8996 runs into various
> > RCU stalls and fails to boot most of the times.
> > 
> > Give both 1003 and 1009 a "type" to ensure they are not filtered out in
> > update_cpu_capabilities().
> 
> Oh nasty. Thanks for debugging and fixing this.
> 
> > Fixes: cce360b54ce6 ("arm64: capabilities: Filter the entries based on a given mask")
> > Cc: stable@vger.kernel.org
> > Reported-by: Mark Brown <broonie@kernel.org>
> > Suggested-by: Will Deacon <will@kernel.org>
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > ---
> >  arch/arm64/kernel/cpu_errata.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
> > index df9465120e2f..cdd8df033536 100644
> > --- a/arch/arm64/kernel/cpu_errata.c
> > +++ b/arch/arm64/kernel/cpu_errata.c
> > @@ -780,6 +780,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
> >  	{
> >  		.desc = "Qualcomm Technologies Falkor/Kryo erratum 1003",
> >  		.capability = ARM64_WORKAROUND_QCOM_FALKOR_E1003,
> > +		.type = ARM64_CPUCAP_SCOPE_LOCAL_CPU,
> >  		.matches = cpucap_multi_entry_cap_matches,
> 
> This should probably be ARM64_CPUCAP_LOCAL_CPU_ERRATUM instead, but I'll
> want Suzuki's ack before I take the change.
> 

Sure thing, will fix!

> >  		.match_list = qcom_erratum_1003_list,
> >  	},
> > @@ -788,6 +789,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
> >  	{
> >  		.desc = "Qualcomm erratum 1009, ARM erratum 1286807",
> >  		.capability = ARM64_WORKAROUND_REPEAT_TLBI,
> > +		.type = ARM64_CPUCAP_SCOPE_LOCAL_CPU,
> >  		ERRATA_MIDR_RANGE_LIST(arm64_repeat_tlbi_cpus),
> 
> ERRATA_MIDR_RANGE_LIST sets the type already, so I think this is redundant.
> 

You're right, I got lost in the macros. Apologies for that.

Will respin the patch.

Thanks,
Bjorn