Messages in this thread | | | Subject | Re: [RFC PATCH] irqchip/gic-v3-its: apply ACPI device based quirks | From | Marc Zyngier <> | Date | Mon, 26 Feb 2018 10:18:20 +0000 |
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Hi Ard,
On 13/02/18 14:11, Ard Biesheuvel wrote: > Reapply the SynQuacer quirk for ITS frames that are matched by 'SCX0005' > based ACPI devices, replacing the dummy fwnode with the one populated by > the ACPI device core. > > This allows the SynQuacer ACPI tables to publish a device node such > as > > Device (ITS0) { > Name (_HID, "SCX0005") > Name (_ADR, 0x30020000) > Name (_DSD, Package () // _DSD: Device-Specific Data > { > ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > Package () { > Package (2) { > "socionext,synquacer-pre-its", > Package () { 0x58000000, 0x200000 } > }, > } > }) > } > > which will trigger the existing quirk that replaces the doorbell > address with the appropriate address in the pre-ITS frame. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > Marc, Lorenzo, > > I am aware that this patch may be seen as controversial, but I would like to > propose it nonetheless. The reason is that this is the only thing standing in > the way of full ACPI support in Socionext SynQuacer based platforms. > > The pre-ITS is a monstrosity, but as it turns out, Socionext had help from > ARM designing it, and the reason we need DT/ACPI based quirks in the first > place is that the IIDR of this GICv3 implementation is simply the ARM Ltd. > one (as they designed the IP)
That's odd. A bit of archaeology shows that ARM indeed designed a pre-ITS, but that one doesn't break isolation at all (it still has a single doorbell). So whatever creative changes Socionext applied to that piece of IP (assuming this is the same IP), they didn't really understand the far reaching impact it has.
> > Please take this into consideration when reviewing this patch, > > Thanks, > Ard. > > drivers/irqchip/irq-gic-v3-its.c | 39 ++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > index 06f025fd5726..a63973baf08a 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -3517,3 +3517,42 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists, > > return 0; > } > + > +#if defined(CONFIG_SOCIONEXT_SYNQUACER_PREITS) && defined(CONFIG_ACPI) > +static acpi_status __init acpi_its_device_probe (acpi_handle handle, > + u32 depth, void *context, > + void **ret) > +{ > + struct acpi_device *adev; > + unsigned long long phys_base; > + struct its_node *its; > + acpi_status status; > + int err; > + > + err = acpi_bus_get_device(handle, &adev); > + if (err) > + return AE_CTRL_TERMINATE; > + > + status = acpi_evaluate_integer(handle, "_ADR", NULL, &phys_base); > + if (ACPI_FAILURE(status)) > + return status; > + > + list_for_each_entry(its, &its_nodes, entry) > + if (its->phys_base == phys_base) { > + irq_domain_free_fwnode(its->fwnode_handle);
That line scares me. What about irq domains that are hold a pointer to this handle? its_init_domain() uses it to construct the LPI domain, and it is now pointing to some free memory.
You'd need to reassign all the domains that match this fwnode before freeing it.
> + its->fwnode_handle = &adev->fwnode; > + its_enable_quirk_socionext_synquacer(its); > + break; > + } > + > + return AE_CTRL_TERMINATE; > +} > + > +static int __init acpi_its_device_probe_init(void) > +{ > + if (!acpi_disabled) > + acpi_get_devices("SCX0005", acpi_its_device_probe, NULL, NULL); > + return 0; > +} > +subsys_initcall_sync(acpi_its_device_probe_init); > +#endif >
Is there any chance that MSIs could be allocated before this kicks in? If that happens, we're in trouble...
Thanks,
M. -- Jazz is not dead. It just smells funny...
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