On Tue, Dec 01, 2020 at 12:59:23PM -0700, Jerry Snitselaar wrote:
>
> Jerry Snitselaar @ 2020-11-30 20:26 MST:
>
> > Jerry Snitselaar @ 2020-11-30 19:58 MST:
> >
> >> When enabling the interrupt code for the tpm_tis driver we have
> >> noticed some systems have a bios issue causing an interrupt storm to
> >> occur. The issue isn't limited to a single tpm or system manufacturer
> >> so keeping a denylist of systems with the issue isn't optimal. Instead
> >> try to detect the problem occurring, disable interrupts, and revert to
> >> polling when it happens.
> >>
> >> Cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> >> Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> >> Cc: Peter Huewe <peterhuewe@xxxxxx>
> >> Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
> >> Cc: Matthew Garrett <mjg59@xxxxxxxxxx>
> >> Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> >> Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
> >> ---
> >> v2: drop tpm_tis specific workqueue and use just system_wq
> >>
> >> drivers/char/tpm/tpm_tis_core.c | 27 +++++++++++++++++++++++++++
> >> drivers/char/tpm/tpm_tis_core.h | 2 ++
> >> 2 files changed, 29 insertions(+)
> >>
> >> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> >> index 23b60583928b..72cc8a5a152c 100644
> >> --- a/drivers/char/tpm/tpm_tis_core.c
> >> +++ b/drivers/char/tpm/tpm_tis_core.c
> >> @@ -24,6 +24,8 @@
> >> #include <linux/wait.h>
> >> #include <linux/acpi.h>
> >> #include <linux/freezer.h>
> >> +#include <linux/workqueue.h>
> >> +#include <linux/kernel_stat.h>
> >> #include "tpm.h"
> >> #include "tpm_tis_core.h"
> >>
> >> @@ -745,9 +747,23 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
> >> {
> >> struct tpm_chip *chip = dev_id;
> >> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> >> + static bool check_storm = true;
> >> + static unsigned int check_start;
> >> u32 interrupt;
> >> int i, rc;
> >>
> >> + if (unlikely(check_storm)) {
> >> + if (!check_start) {
> >> + check_start = jiffies_to_msecs(jiffies);
> >> + } else if ((kstat_irqs(priv->irq) > 1000) &&
> >> + (jiffies_to_msecs(jiffies) - check_start < 500)) {
> >> + check_storm = false;
> >> + schedule_work(&priv->storm_work);
> >> + } else if (jiffies_to_msecs(jiffies) - check_start >= 500) {
> >> + check_storm = false;
> >> + }
> >> + }
> >> +
> >> rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
> >> if (rc < 0)
> >> return IRQ_NONE;
> >> @@ -987,6 +1003,14 @@ static const struct tpm_class_ops tpm_tis = {
> >> .clk_enable = tpm_tis_clkrun_enable,
> >> };
> >>
> >> +static void tpm_tis_storm_work(struct work_struct *work)
> >> +{
> >> + struct tpm_tis_data *priv = container_of(work, struct tpm_tis_data, storm_work);
> >> +
> >> + disable_interrupts(priv->chip);
> >> + dev_warn(&priv->chip->dev, "Interrupt storm detected, using polling.\n");
> >> +}
> >> +
> >> int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
> >> const struct tpm_tis_phy_ops *phy_ops,
> >> acpi_handle acpi_dev_handle)
> >> @@ -1003,6 +1027,9 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
> >> if (IS_ERR(chip))
> >> return PTR_ERR(chip);
> >>
> >> + priv->chip = chip;
> >> + INIT_WORK(&priv->storm_work, tpm_tis_storm_work);
> >> +
> >> #ifdef CONFIG_ACPI
> >> chip->acpi_dev_handle = acpi_dev_handle;
> >> #endif
> >> diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
> >> index edeb5dc61c95..5630f294dc0c 100644
> >> --- a/drivers/char/tpm/tpm_tis_core.h
> >> +++ b/drivers/char/tpm/tpm_tis_core.h
> >> @@ -95,6 +95,8 @@ struct tpm_tis_data {
> >> u16 clkrun_enabled;
> >> wait_queue_head_t int_queue;
> >> wait_queue_head_t read_queue;
> >> + struct work_struct storm_work;
> >> + struct tpm_chip *chip;
> >> const struct tpm_tis_phy_ops *phy_ops;
> >> unsigned short rng_quality;
> >> };
> >
> > I've tested this with the Intel platform that has an Infineon chip that
> > I found the other week. It works, but isn't the complete fix. With this
> > on top of James' patchset I sometimes see the message "Lost Interrupt
> > waiting for TPM stat", so I guess there needs to be a check in
> > wait_for_tpm_stat and request_locality to see if interrupts were
> > disabled when the wait_event_interruptible_timeout call times out.
>
> As kernel test robot pointed out. kstat_irqs isn't visible when tpm_tis
> builds as a module. It looks like it is only called by kstat_irq_usrs,
> and that is only by the fs/proc code. I have a patch to export it, but
> the i915 driver open codes their own version instead of using it. Is
> there any reason not to export it?
If you add a patch that exports it, then for coherency it'd be better to
also patch i915 driver. Jani?
/Jarkko
