From: Mark Brown <broonie@kernel.org>
To: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v7 1/4] arm64: Add initial support for E0PD
Date: Thu, 7 Nov 2019 11:55:06 +0000 [thread overview]
Message-ID: <20191107115506.GB6159@sirena.co.uk> (raw)
In-Reply-To: <04d20903-f7f0-18d4-b671-4c382a47c5e2@arm.com>
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On Thu, Nov 07, 2019 at 10:12:30AM +0000, Suzuki K Poulose wrote:
> > +static void cpu_enable_e0pd(struct arm64_cpu_capabilities const *cap)
> > +{
> > + /*
> > + * The cpu_enable() callback gets called even on CPUs that
> > + * don't detect the feature so we need to verify if we can
> > + * enable.
> > + */
> > + if (this_cpu_has_cap(ARM64_HAS_E0PD))
> > + sysreg_clear_set(tcr_el1, 0, TCR_E0PD1);
> > +}
> Given that this is a SYSTEM_FEATURE now, we don't need the extra check.
> All CPUs are guaranteed to have the feature, otherwise they would be
> rejected early.
It's not strictly required but it does no harm, helps people who are
doing CPU local stuff see that this might be an issue if they just look
at other users rather than the header and it means that if someone
changes things (I'm actually been sitting on a patch for that but I want
to postpone any discussion about that until after at least the initial
three patches are merged).
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next prev parent reply other threads:[~2019-11-07 11:55 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-06 13:00 [PATCH v7 0/4] E0PD support Mark Brown
2019-11-06 13:00 ` [PATCH v7 1/4] arm64: Add initial support for E0PD Mark Brown
2019-11-07 10:12 ` Suzuki K Poulose
2019-11-07 11:55 ` Mark Brown [this message]
2019-11-06 13:00 ` [PATCH v7 2/4] arm64: Factor out checks for KASLR in KPTI code into separate function Mark Brown
2019-11-06 13:00 ` [PATCH v7 3/4] arm64: Don't use KPTI where we have E0PD Mark Brown
2019-11-07 12:01 ` Suzuki K Poulose
2019-11-07 14:37 ` Mark Brown
2019-11-07 15:03 ` Suzuki K Poulose
2019-11-08 14:10 ` Mark Brown
2019-11-07 14:48 ` Mark Brown
2019-11-06 13:00 ` [PATCH v7 4/4] arm64: Use a variable to store non-global mappings decision Mark Brown
2019-11-07 11:11 ` Suzuki K Poulose
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