From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v8 3/4] arm64: Don't use KPTI where we have E0PD
Date: Mon, 11 Nov 2019 17:36:19 +0000 [thread overview]
Message-ID: <c5c94d94-d3f0-4444-3a1e-15bfaf912c72@arm.com> (raw)
In-Reply-To: <20191111163630.GB4264@sirena.co.uk>
On 11/11/2019 16:36, Mark Brown wrote:
> On Mon, Nov 11, 2019 at 02:36:34PM +0000, Suzuki K Poulose wrote:
>> On 08/11/2019 17:01, Mark Brown wrote:
>
>>> + /*
>>> + * E0PD does a similar job to KPTI so can be used instead
>>> + * where available. This will only run before the cpufeature
>
>> s/This will only run/This will run/ ?
>
> Both with and without patch 4 we only check this when cpucaps aren't
> ready - with just this patch this is done in arm64_kernel_use_ng_mappings()
I feel the statement
"This will only run before the cpufeature code has usefully run and we
eventually check on all CPUs so we can and must check locally."
is confusing and I don't see how it implies :
"the code is run early enough in the boot *and* also from the cpufeature
framework."
It would be good to rephrase it, if that is not what you mean.
> where it has a check for caps being ready prior to checking if KASLR
> requirs KPTI, or otherwise the checks are from the cpufeature code while
> it's running. With patch 4 it's only called from the cpufeature code or
> from the early init check.
It may be a good idea to reword it.
Cheers
Suzuki
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next prev parent reply other threads:[~2019-11-11 17:36 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-08 17:01 [PATCH v8 0/4] E0PD support Mark Brown
2019-11-08 17:01 ` [PATCH v8 1/4] arm64: Add initial support for E0PD Mark Brown
2019-11-11 14:22 ` Suzuki K Poulose
2019-11-11 17:35 ` Mark Brown
2019-11-08 17:01 ` [PATCH v8 2/4] arm64: Factor out checks for KASLR in KPTI code into separate function Mark Brown
2019-11-11 14:31 ` Suzuki K Poulose
2019-11-08 17:01 ` [PATCH v8 3/4] arm64: Don't use KPTI where we have E0PD Mark Brown
2019-11-11 14:36 ` Suzuki K Poulose
2019-11-11 16:36 ` Mark Brown
2019-11-11 17:36 ` Suzuki K Poulose [this message]
2019-11-08 17:01 ` [PATCH v8 4/4] arm64: Use a variable to store non-global mappings decision Mark Brown
2019-11-11 14:39 ` Suzuki K Poulose
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