From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: cpu_errata: Remove ARM64_MISMATCHED_CACHE_LINE_SIZE
Date: Wed, 19 Sep 2018 11:56:15 +0100 [thread overview]
Message-ID: <20180919105615.GG25094@arm.com> (raw)
In-Reply-To: <233e9a8d-b3ef-9b9c-208b-f0fd9ea4e3fe@arm.com>
On Wed, Sep 19, 2018 at 11:53:43AM +0100, Suzuki K Poulose wrote:
> On 09/19/2018 11:41 AM, Will Deacon wrote:
> >There's no need to treat mismatched cache-line sizes reported by CTR_EL0
> >differently to any other mismatched fields that we treat as "STRICT" in
> >the cpufeature code. In both cases we need to trap and emulate EL0
> >accesses to the register, so drop ARM64_MISMATCHED_CACHE_LINE_SIZE and
> >rely on ARM64_MISMATCHED_CACHE_TYPE instead.
>
> The only reason was to avoid trapping the kernel accesses of CTR_EL0
> for cache line sizes if there were no differences. If we are ok with
> that, I am fine with the patch.
It's not a "trap" as such though, is it? We just load the safe val and
return that. I think that makes more sense, because if somebody uses
read_ctr to try and read something like IDC or DIC, they probably want
a sanitised copy on a mismatch.
Will
next prev parent reply other threads:[~2018-09-19 10:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-19 10:41 [PATCH] arm64: cpu_errata: Remove ARM64_MISMATCHED_CACHE_LINE_SIZE Will Deacon
2018-09-19 10:53 ` Suzuki K Poulose
2018-09-19 10:56 ` Will Deacon [this message]
2018-09-19 10:59 ` Suzuki K Poulose
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