From: Lukas Wunner <lukas@wunner.de>
To: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Cc: "Jarkko Sakkinen" <jarkko@kernel.org>,
oe-lkp@lists.linux.dev, lkp@intel.com,
linux-kernel@vger.kernel.org,
"Michael Niewöhner" <linux@mniewoehner.de>,
linux-integrity@vger.kernel.org,
"Philipp Rosenberger" <p.rosenberger@kunbus.com>,
jsnitsel@redhat.com, peterz@infradead.org
Subject: Re: [linus:master] [tpm, tpm_tis] e644b2f498: RIP:acpi_safe_halt
Date: Thu, 11 May 2023 16:16:07 +0200 [thread overview]
Message-ID: <20230511141607.GA32208@wunner.de> (raw)
In-Reply-To: <42ea93a1-3186-b8ff-c317-d51f3e13856e@kunbus.com>
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.
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.
By reusing the genirq subsystem's irqs_unhandled infrastructure,
you avoid having to reimplement all of that.
Thanks,
Lukas
next prev parent reply other threads:[~2023-05-11 14:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <202305041325.ae8b0c43-yujie.liu@intel.com>
2023-05-10 22:00 ` [linus:master] [tpm, tpm_tis] e644b2f498: RIP:acpi_safe_halt Jarkko Sakkinen
2023-05-11 11:22 ` Lino Sanfilippo
2023-05-11 14:16 ` Lukas Wunner [this message]
2023-05-11 14:22 ` Lino Sanfilippo
2023-05-11 14:59 ` Jerry Snitselaar
2023-05-29 15:07 ` Michael Niewöhner
2023-05-29 20:58 ` Jerry Snitselaar
2023-05-30 14:40 ` Michael Niewöhner
2023-05-30 16:27 ` Jerry Snitselaar
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