powerpc/security: Fix spectre_v2 reporting

Michael Ellerman patch-notifications at ellerman.id.au
Fri Mar 22 23:21:41 AEDT 2019

On Thu, 2019-03-21 at 04:24:33 UTC, Michael Ellerman wrote:
> When I updated the spectre_v2 reporting to handle software count cache
> flush I got the logic wrong when there's no software count cache
> enabled at all.
> The result is that on systems with the software count cache flush
> disabled we print:
>   Mitigation: Indirect branch cache disabled, Software count cache flush
> Which correctly indicates that the count cache is disabled, but
> incorrectly says the software count cache flush is enabled.
> The root of the problem is that we are trying to handle all
> combinations of options. But we know now that we only expect to see
> the software count cache flush enabled if the other options are false.
> So split the two cases, which simplifies the logic and fixes the bug.
> We were also missing a space before "(hardware accelerated)".
> The result is we see one of:
>   Mitigation: Indirect branch serialisation (kernel only)
>   Mitigation: Indirect branch cache disabled
>   Mitigation: Software count cache flush
>   Mitigation: Software count cache flush (hardware accelerated)
> Fixes: ee13cb249fab ("powerpc/64s: Add support for software count cache flush")
> Cc: stable at vger.kernel.org # v4.19+
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
> Reviewed-by: Michael Neuling <mikey at neuling.org>
> Reviewed-by: Diana Craciun <diana.craciun at nxp.com>

Applied to powerpc fixes.



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