Re: [PATCH v3 03/32] irqchip/gic-v3: Workaround Cavium TX1 erratum when reading GICD_TYPER2

Robert Richter
2020-03-10T12:35:32Z

On 10.03.20 11:41:09, Marc Zyngier wrote:
> On 2020-03-09 22:11, Robert Richter wrote:
> > On 24.12.19 11:10:26, Marc Zyngier wrote:

> > > @@ -1502,6 +1512,12 @@ static const struct gic_quirk gic_quirks[] = {
> > > .mask = 0xffffffff,
> > > .init = gic_enable_quirk_hip06_07,
> > > },
> > > + {
> > > + .desc = "GICv3: Cavium TX1 GICD_TYPER2 erratum",
> >
> > There is no errata number yet.
>
> Please let me know when/if you obtain one.

Yes, will do.

>
> >
> > > + .iidr = 0xa100034c,
> > > + .mask = 0xfff00fff,
> > > + .init = gic_enable_quirk_tx1,
> >
> > All TX1 and OcteonTX parts are affected, which is a0-a7 and b0-b7. So
> > the iidr/mask should be:
> >
> > .iidr = 0xa000034c,
> > .mask = 0xe8f00fff,
>
> Thanks, that's pretty helpful. I'll update the patch with these values
> and the corresponding description.

Thanks for the update.

>
> > > + },
> > > {
> > > }
> > > };
> > > @@ -1577,7 +1593,12 @@ static int __init gic_init_bases(void __iomem
> > > *dist_base,
> > > pr_info("%d SPIs implemented\n", GIC_LINE_NR - 32);
> > > pr_info("%d Extended SPIs implemented\n", GIC_ESPI_NR);
> > >
> > > - gic_data.rdists.gicd_typer2 = readl_relaxed(gic_data.dist_base +
> > > GICD_TYPER2);
> > > + /*
> > > + * ThunderX1 explodes on reading GICD_TYPER2, in total violation
> > > + * of the spec (which says that reserved addresses are RES0).
> > > + */
> > > + if (!(gic_data.flags & FLAGS_WORKAROUND_GICD_TYPER2_TX1))
> > > + gic_data.rdists.gicd_typer2 = readl_relaxed(gic_data.dist_base +
> > > GICD_TYPER2);
> >
> > You already said that checking for ArchRev of GICD_PIDR2 isn't an
> > option here. Though, it could...
>
> Once GICv3.2 starts using this register as well (because GICD_TYPER is
> already completely full), we'd have to fix it again. There is also the thing
> you hinted at in the other thread: TX1 will generate a SEA on every reserved
> GICD registers, so we may need to protect more than just this one over time,
> and maybe more than just in the distributor.

I am fine with both. And right, it would be possibly needed for other
ranges too.

Thanks,

-Robert

>
> Thanks,
>
> M.
> --
> Jazz is not dead. It just smells funny...