svn commit: r327876 - in head/sys/arm64: arm64 include

[Warner Losh]

On Fri, Jan 12, 2018 at 7:15 AM, Andrew Turner <andrew at freebsd.org> wrote:

>
>
> On 12 Jan 2018, at 14:10, Marcin Wojtas <mw at semihalf.com> wrote:
>
> Hi Andrew,
>
>
>
> 2018-01-12 15:01 GMT+01:00 Andrew Turner <andrew at freebsd.org>:
>
> Author: andrew
> Date: Fri Jan 12 14:01:38 2018
> New Revision: 327876
> URL: https://svnweb.freebsd.org/changeset/base/327876
>
> Log:
>  Workaround Spectre Variant 2 on arm64.
>
>  We need to handle two cases:
>
>  1. One process attacking another process.
>  2. A process attacking the kernel.
>
>  For the first case we clear the branch predictor state on context switch
>  between different processes. For the second we do this when taking an
>  instruction abort on a non-userspace address.
>
>  To clear the branch predictor state a per-CPU function pointer has been
>  added. This is set by the new cpu errata code based on if the CPU is
>  known to be affected.
>
>  On Cortex-A57, A72, A73, and A75 we call into the PSCI firmware as newer
>  versions of this will clear the branch predictor state for us.
>
>  It has been reported the ThunderX is unaffected, however the ThunderX2 is
>  vulnerable. The Qualcomm Falkor core is also affected. As FreeBSD doesn't
>  yet run on the ThunderX2 or Falkor no workaround is included for these
> CPUs.
>
>
> Regardless ThunderX2 / Falkor work-arounds, do I understand correctly
> that pure CA72 machines, such as Marvell Armada 7k/8k are immune to
> Variant 2 now?
>
>
> It is my understanding that the A72 will be immune with this patch and an
> updated Arm Trusted Firmware as documented in [1].
>
> Andrew
>
> [1] https://github.com/ARM-software/arm-trusted-firmware/
> wiki/ARM-Trusted-Firmware-Security-Advisory-TFV-6
>

Are you also working on aarch32 mitigation?

Warner