Hi Mark,
On Thu, Apr 16, 2020 at 2:56 PM Mark Rutland <mark.rutland@xxxxxxx> wrote:
> On Thu, Apr 16, 2020 at 01:56:58PM +0200, Geert Uytterhoeven wrote:
> > Currently the user is asked about enabling support for each and every
> > vendor-specific erratum, even when support for the specific platform is
> > not enabled.
> >
> > Fix this by adding platform dependencies to the config options
> > controlling support for vendor-specific errata.
> >
> > Note that FUJITSU_ERRATUM_010001 is left untouched, as no config symbol
> > exists for the Fujitsu A64FX platform.
> >
> > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
>
> I'm not su1re that it makes sense to do this in general, becaose the
> ARCH_* platform symbols are about plactform/SoC support (e.g. pinctrl
> drivers), and these are (mostly) CPU-local and/or VM-visible.
>
> I think that it makes sense for those to be independent because:
>
> * future SoCs in the same family might not need the same CPU errata
> workarounds, and it's arguably just as confusing to have the option
> there.
True. But at least the dependency restricts the confusion to a smaller
audience.
> * It prevents building a minimal VM image with all (non-virtualized)
> platform support disabled, but all possible (VM-visible) errata
> options enabled. I do that occassionally for testing/analysis, and I
> can imagine this is useful for those building images that are only
> intended to be used in VMs.
Oh, you also want to build a "generic" guest kernel, with all ARCH_*
symbols disabled. Let's hope a maleficent user cannot disable errata
mitigations in the guest kernel and break the host ;-)
And perhaps you do want to enable some platform-specific drivers for
VFIO pass-through? Hence having ARCH_* dependencies on those drivers
means they cannot be enabled :-( Hmm...
> I think the change to SOCIONEXT_SYNQUACER_PREITS makes sense given
> that's a platform-level detail. Arguably that should be moved into
> drivers/irqchip/Kconfig.
OK, makes sense.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
