Messages in this thread | | | Date | Tue, 10 Mar 2020 11:41:09 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH v3 03/32] irqchip/gic-v3: Workaround Cavium TX1 erratum when reading GICD_TYPER2 |
| |
Hi Robert,
On 2020-03-09 22:11, Robert Richter wrote: > On 24.12.19 11:10:26, Marc Zyngier wrote: >> Despite the architecture spec being extremely clear about the fact >> that reserved registers in the GIC distributor memory map are RES0 >> (and thus are not allowed to generate an exception), the Cavium >> ThunderX (aka TX1) SoC explodes as such: >> >> [ 0.000000] GICv3: GIC: Using split EOI/Deactivate mode >> [ 0.000000] GICv3: 128 SPIs implemented >> [ 0.000000] GICv3: 0 Extended SPIs implemented >> [ 0.000000] Internal error: synchronous external abort: 96000210 >> [#1] SMP >> [ 0.000000] Modules linked in: >> [ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted >> 5.4.0-rc4-00035-g3cf6a3d5725f #7956 >> [ 0.000000] Hardware name: cavium,thunder-88xx (DT) >> [ 0.000000] pstate: 60000085 (nZCv daIf -PAN -UAO) >> [ 0.000000] pc : __raw_readl+0x0/0x8 >> [ 0.000000] lr : gic_init_bases+0x110/0x560 >> [ 0.000000] sp : ffff800011243d90 >> [ 0.000000] x29: ffff800011243d90 x28: 0000000000000000 >> [ 0.000000] x27: 0000000000000018 x26: 0000000000000002 >> [ 0.000000] x25: ffff8000116f0000 x24: ffff000fbe6a2c80 >> [ 0.000000] x23: 0000000000000000 x22: ffff010fdc322b68 >> [ 0.000000] x21: ffff800010a7a208 x20: 00000000009b0404 >> [ 0.000000] x19: ffff80001124dad0 x18: 0000000000000010 >> [ 0.000000] x17: 000000004d8d492b x16: 00000000f67eb9af >> [ 0.000000] x15: ffffffffffffffff x14: ffff800011249908 >> [ 0.000000] x13: ffff800091243ae7 x12: ffff800011243af4 >> [ 0.000000] x11: ffff80001126e000 x10: ffff800011243a70 >> [ 0.000000] x9 : 00000000ffffffd0 x8 : ffff80001069c828 >> [ 0.000000] x7 : 0000000000000059 x6 : ffff8000113fb4d1 >> [ 0.000000] x5 : 0000000000000001 x4 : 0000000000000000 >> [ 0.000000] x3 : 0000000000000000 x2 : 0000000000000000 >> [ 0.000000] x1 : 0000000000000000 x0 : ffff8000116f000c >> [ 0.000000] Call trace: >> [ 0.000000] __raw_readl+0x0/0x8 >> [ 0.000000] gic_of_init+0x188/0x224 >> [ 0.000000] of_irq_init+0x200/0x3cc >> [ 0.000000] irqchip_init+0x1c/0x40 >> [ 0.000000] init_IRQ+0x160/0x1d0 >> [ 0.000000] start_kernel+0x2ec/0x4b8 >> [ 0.000000] Code: a8c47bfd d65f03c0 d538d080 d65f03c0 (b9400000) >> >> when reading the GICv4.1 GICD_TYPER2 register, which is unexpected... >> >> Work around it by adding a new quirk flagging all the A1 revisions >> of the distributor, but it remains unknown whether this could affect >> other revisions of this SoC (or even other SoCs from the same silicon >> vendor). >> >> Signed-off-by: Marc Zyngier <maz@kernel.org> >> --- >> drivers/irqchip/irq-gic-v3.c | 23 ++++++++++++++++++++++- >> 1 file changed, 22 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/irqchip/irq-gic-v3.c >> b/drivers/irqchip/irq-gic-v3.c >> index 286f98222878..640d4db65b78 100644 >> --- a/drivers/irqchip/irq-gic-v3.c >> +++ b/drivers/irqchip/irq-gic-v3.c >> @@ -34,6 +34,7 @@ >> #define GICD_INT_NMI_PRI (GICD_INT_DEF_PRI & ~0x80) >> >> #define FLAGS_WORKAROUND_GICR_WAKER_MSM8996 (1ULL << 0) >> +#define FLAGS_WORKAROUND_GICD_TYPER2_TX1 (1ULL << 1) >> >> struct redist_region { >> void __iomem *redist_base; >> @@ -1464,6 +1465,15 @@ static bool gic_enable_quirk_msm8996(void >> *data) >> return true; >> } >> >> +static bool gic_enable_quirk_tx1(void *data) >> +{ >> + struct gic_chip_data *d = data; >> + >> + d->flags |= FLAGS_WORKAROUND_GICD_TYPER2_TX1; >> + >> + return true; >> +} >> + >> static bool gic_enable_quirk_hip06_07(void *data) >> { >> struct gic_chip_data *d = data; >> @@ -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.
> >> + .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.
>> + }, >> { >> } >> }; >> @@ -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.
Thanks,
M. -- Jazz is not dead. It just smells funny...
| |