Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Thu, 16 Apr 2020 17:38:07 +0200 | Subject | Re: [PATCH 2/2] [RFC] arm64: Add dependencies to vendor-specific errata |
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Hi Mark,
On Thu, Apr 16, 2020 at 2:56 PM Mark Rutland <mark.rutland@arm.com> 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@glider.be> > > 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@linux-m68k.org
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
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