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Date:   Thu, 31 Jan 2019 17:54:36 +0000
From:   Andre Przywara <andre.przywara@arm.com>
To:     Jeremy Linton <jeremy.linton@arm.com>
Cc:     linux-arm-kernel@lists.infradead.org, stefan.wahren@i2se.com,
        mlangsdo@redhat.com, suzuki.poulose@arm.com, marc.zyngier@arm.com,
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        will.deacon@arm.com, linux-kernel@vger.kernel.org,
        steven.price@arm.com, ykaukab@suse.de, dave.martin@arm.com,
        shankerd@codeaurora.org
Subject: Re: [PATCH v4 08/12] arm64: Advertise mitigation of Spectre-v2, or
 lack thereof
Message-ID: <20190131175436.1c24f7b8@donnerap.cambridge.arm.com>
In-Reply-To: <20190125180711.1970973-9-jeremy.linton@arm.com>
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        <20190125180711.1970973-9-jeremy.linton@arm.com>
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On Fri, 25 Jan 2019 12:07:07 -0600
Jeremy Linton <jeremy.linton@arm.com> wrote:

> From: Marc Zyngier <marc.zyngier@arm.com>
> 
> We currently have a list of CPUs affected by Spectre-v2, for which
> we check that the firmware implements ARCH_WORKAROUND_1. It turns
> out that not all firmwares do implement the required mitigation,
> and that we fail to let the user know about it.
> 
> Instead, let's slightly revamp our checks, and rely on a whitelist
> of cores that are known to be non-vulnerable, and let the user know
> the status of the mitigation in the kernel log.

Yeah, this looks better, I was scratching my head about that
blacklist already.

> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> [This makes more sense in front of the sysfs patch]
> [Pick pieces of that patch into this and move it earlier]
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>

Reviewed-by: Andre Przywara <andre.przywara@arm.com>

> ---  arch/arm64/kernel/cpu_errata.c | 104 +++++++++++++++++----------------
> 1 file changed, 54 insertions(+), 50 deletions(-)
> 
....