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 <jar...@kernel.org>
> Cc: Jason Gunthorpe <j...@ziepe.ca>
> Cc: Peter Huewe <peterhu...@gmx.de>
> Cc: James Bottomley <james.bottom...@hansenpartnership.com>
> Cc: Matthew Garrett <mj...@google.com>
> Cc: Hans de Goede <hdego...@redhat.com>
> Signed-off-by: Jerry Snitselaar <jsnit...@redhat.com>
> ---
> 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.
