linux-kernel - Re: [PATCH v4 2/5] arm64: errata: Assume that unknown CPUs _are

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAD=FV=XZnb-c+9LVYWmA0EZPTX0enpZQdwokRanKZ78RRQOAzw@mail.gmail.com>
Date: Wed, 12 Feb 2025 10:05:41 -0800
From: Doug Anderson <dianders@...omium.org>
To: Catalin Marinas <catalin.marinas@....com>
Cc: James Morse <james.morse@....com>, Will Deacon <will@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, Roxana Bradescu <roxabee@...gle.com>, 
	Julius Werner <jwerner@...omium.org>, bjorn.andersson@....qualcomm.com, 
	Trilok Soni <quic_tsoni@...cinc.com>, linux-arm-msm@...r.kernel.org, 
	Florian Fainelli <florian.fainelli@...adcom.com>, linux-arm-kernel@...ts.infradead.org, 
	Jeffrey Hugo <quic_jhugo@...cinc.com>, Scott Bauer <sbauer@...cinc.com>, stable@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/5] arm64: errata: Assume that unknown CPUs _are_
 vulnerable to Spectre BHB

Hi,

On Wed, Feb 12, 2025 at 9:52 AM Catalin Marinas <catalin.marinas@....com> wrote:
>
> On Wed, Jan 29, 2025 at 11:14:20AM -0800, Doug Anderson wrote:
> > On Wed, Jan 29, 2025 at 8:43 AM James Morse <james.morse@....com> wrote:
> > > Arm have recently updated that table of CPUs
> > > with extra entries (thanks for picking those up!) - but now that patch can't be easily
> > > applied to older kernels.
> > > I suspect making the reporting assuming-vulnerable may make other CPUs come out of the
> > > wood work too...
> > >
> > > Could we avoid changing this unless we really need to?
> >
> > Will / Catalin: Do either of you have an opinion here?
>
> Is this about whether to report "vulnerable" for unknown CPUs? I think
> Will suggested this:
>
> https://lore.kernel.org/all/20241219175128.GA25477@willie-the-truck/

Right. The patch in its current form is in direct response to what
Will requested and then subsequent feedback on the mailing lists from
Julius Werner.

> That said, some patch splitting will help to make review easier. Should
> such change be back-portable as well? I think so, it's not only for CPUs
> we'll see in the future.

Personally, I don't think the patch will be terribly hard to backport
as-is. I would expect it to just cherry-pick cleanly since it only
touches spectre code and I'd imagine all that stuff is being
backported verbatim. I did at least confirm that it applies cleanly to
v5.15.178 (I didn't try compiling though). I guess there are conflicts
back to v5.10.234, though...

While I've had plenty of time to work on this patch in the last three
months since I posted the early versions, recently my assignments at
work have changed and I have a lot less time to work on this patch
series. If breaking this up is blocking this patch from landing then
I'll try to find some time in the next month or two to do it. Let me
know.

-Doug