Hi Lukas, On 11.05.23 16:16, Lukas Wunner wrote: > ATTENTION: This e-mail is from an external sender. Please check attachments and links before opening e.g. with mouseover. > > > On Thu, May 11, 2023 at 01:22:19PM +0200, Lino Sanfilippo wrote: >> Since beside the one reported by Peter Zijlstra >> (https://lore.kernel.org/linux-integrity/CSJ0AD1CFYQP.T6T68M6ZVK49@suppilovahvero/T/#t) >> we have another interrupt storm here, it is probably the best to handle those in general >> and to disable interrupts in this case to fall back to polling (this is also what Jerry >> suggested in the thread above). >> >> I will try to provide a patch for this. > > In tpm_tis_probe_irq_single(), after you've requested the irq, > you could convert it to a struct irq_desc (via irq_to_desc() > from <linux/irqnr.h>) and cache that pointer in priv. > > Then in tis_int_handler(), you could access the irqs_unhandled > member of struct irq_desc (from <linux/irqdesc.h>) and check > if it exceeds, say, 5000. This is the solution I am currently working on, but thanks for confirming that I am on the right track with this :) > > If it does, schedule a work_struct which calls disable_interrupts(). > You can't call that from the IRQ handler because devm_free_irq() > waits for the IRQ handler to finish, so you'd deadlock. You *can* > of course clear the TPM_GLOBAL_INT_ENABLE bit from the IRQ handler, > though it's unclear to me if that's sufficient to quiesce the > interrupt line. > Will try this, thx. > By reusing the genirq subsystem's irqs_unhandled infrastructure, > you avoid having to reimplement all of that. > Agreed. Regards, Lino > Thanks, > > Lukas
