Re: [PATCH v4 08/12] arm64: Advertise mitigation of Spectre-v2, or lack thereof

From: Andre Przywara
Date: Thu Jan 31 2019 - 12:54:48 EST


On Fri, 25 Jan 2019 12:07:07 -0600
Jeremy Linton <jeremy.linton@xxxxxxx> wrote:

> From: Marc Zyngier <marc.zyngier@xxxxxxx>
>
> 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@xxxxxxx>
> [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@xxxxxxx>

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

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