James Bottomley @ 2020-10-01 11:09 MST:
> If a TIS TPM doesn't have legacy cycles, any write to the interrupt
> registers is ignored unless a locality is active. This means even to
> set up the interrupt vectors a locality must first be activated. Fix
> this by activating the 0 locality in the interrupt probe setup.
>
> Since the TPM_EOI signalling also requires an active locality, the
> interrupt routine cannot end an interrupt if the locality is released.
> This can lead to a situation where the TPM goes command ready after
> locality release and since the interrupt cannot be ended it refires
> continuously. Fix this by disabling all interrupts except locality
> change when a locality is released (this only fires when a locality
> becomes active, meaning the TPM_EOI should work).
>
> Finally, since we now disable all status based interrupts in the
> locality release, they must be re-enabled before waiting to check the
> condition, so add interrupt enabling to the status wait.
>
> Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
>
> ---
>
> v2: renamed functions
> ---
> drivers/char/tpm/tpm_tis_core.c | 125 ++++++++++++++++++++++++++------
> 1 file changed, 101 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 431919d5f48a..0c07da8cd680 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -29,6 +29,46 @@
>
> static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value);
>
> +static void tpm_tis_enable_interrupt(struct tpm_chip *chip, u8 mask)
> +{
> + struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> + u32 intmask;
> +
> + /* Take control of the TPM's interrupt hardware and shut it off */
> + tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
> +
> + intmask |= mask | TPM_GLOBAL_INT_ENABLE;
> +
> + tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
> +}
> +
> +static void tpm_tis_disable_interrupt(struct tpm_chip *chip, u8 mask)
> +{
> + struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> + u32 intmask;
> +
> + /* Take control of the TPM's interrupt hardware and shut it off */
> + tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
> +
> + intmask &= ~mask;
> +
> + tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
> +}
> +
> +static void tpm_tis_enable_stat_interrupts(struct tpm_chip *chip, u8 stat)
> +{
> + u32 mask = 0;
> +
> + if (stat & TPM_STS_COMMAND_READY)
> + mask |= TPM_INTF_CMD_READY_INT;
> + if (stat & TPM_STS_VALID)
> + mask |= TPM_INTF_STS_VALID_INT;
> + if (stat & TPM_STS_DATA_AVAIL)
> + mask |= TPM_INTF_DATA_AVAIL_INT;
> +
> + tpm_tis_enable_interrupt(chip, mask);
> +}
> +
> static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
> bool check_cancel, bool *canceled)
> {
> @@ -65,11 +105,14 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
> timeout = stop - jiffies;
> if ((long)timeout <= 0)
> return -ETIME;
> + tpm_tis_enable_stat_interrupts(chip, mask);
> rc = wait_event_interruptible_timeout(*queue,
> wait_for_tpm_stat_cond(chip, mask, check_cancel,
> &canceled),
> timeout);
> if (rc > 0) {
> + if (rc == 1)
> + dev_err(&chip->dev, "Lost Interrupt waiting for TPM stat\n");
With my proposed patch to check for the interrupt storm condition I
sometimes see this message. Do you think it would make sense to have a
check here and in the request_locality location to see that
TPM_CHIP_FLAG is still enabled? It will print a message about the
interrupt storm being detected, and switching to polling, so I don't
know if this will cause confusion for people to have this show up as
well in that case.
> if (canceled)
> return -ECANCELED;
> return 0;
> @@ -138,6 +181,28 @@ static bool check_locality(struct tpm_chip *chip, int l)
> static int release_locality(struct tpm_chip *chip, int l)
> {
> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> + u32 int_status;
> + int rc;
> +
> + /*
> + * Note that once we relinquish the locality, all writes to
> + * the interrupt registers become ineffective meaning we can't
> + * do a TPM_EOI. This means we must disable every interrupt
> + * except the locality change one to avoid interrupt
> + * storms.
> + */
> + tpm_tis_disable_interrupt(chip, TPM_INTF_CMD_READY_INT
> + | TPM_INTF_STS_VALID_INT
> + | TPM_INTF_DATA_AVAIL_INT);
> +
> + rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &int_status);
> + if (rc < 0)
> + return rc;
> +
> + /* Clear all pending */
> + rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), int_status);
> + if (rc < 0)
> + return rc;
>
> tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);
>
> @@ -164,12 +229,17 @@ static int request_locality(struct tpm_chip *chip, int l)
> timeout = stop - jiffies;
> if ((long)timeout <= 0)
> return -1;
> +
> rc = wait_event_interruptible_timeout(priv->int_queue,
> (check_locality
> (chip, l)),
> timeout);
> - if (rc > 0)
> + if (rc > 1)
> + return l;
> + if (rc == 1) {
> + dev_info(&chip->dev, "Lost Interrupt waiting for locality\n");
> return l;
> + }
> if (rc == -ERESTARTSYS && freezing(current)) {
> clear_thread_flag(TIF_SIGPENDING);
> goto again;
> @@ -465,6 +535,10 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
> irq = priv->irq;
> priv->irq = 0;
> chip->flags &= ~TPM_CHIP_FLAG_IRQ;
> + tpm_tis_enable_interrupt(chip, TPM_INTF_CMD_READY_INT
> + | TPM_INTF_LOCALITY_CHANGE_INT
> + | TPM_INTF_DATA_AVAIL_INT
> + | TPM_INTF_STS_VALID_INT);
> rc = tpm_tis_send_main(chip, buf, len);
> priv->irq = irq;
> chip->flags |= TPM_CHIP_FLAG_IRQ;
> @@ -719,7 +793,7 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
> * irq is seen then leave the chip setup for IRQ operation, otherwise reverse
> * everything and leave in polling mode. Returns 0 on success.
> */
> -static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
> +static int tpm_tis_probe_irq_single(struct tpm_chip *chip,
> int flags, int irq)
> {
> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> @@ -753,9 +827,11 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
> if (rc < 0)
> return rc;
>
> - /* Turn on */
> - rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality),
> - intmask | TPM_GLOBAL_INT_ENABLE);
> + /*
> + * Turn on. The locality change interrupt is the only one
> + * always enabled
> + */
> + tpm_tis_enable_interrupt(chip, TPM_INTF_LOCALITY_CHANGE_INT);
> if (rc < 0)
> return rc;
>
> @@ -787,7 +863,7 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
> * do not have ACPI/etc. We typically expect the interrupt to be declared if
> * present.
> */
> -static void tpm_tis_probe_irq(struct tpm_chip *chip, u32 intmask)
> +static void tpm_tis_probe_irq(struct tpm_chip *chip)
> {
> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> u8 original_int_vec;
> @@ -801,11 +877,9 @@ static void tpm_tis_probe_irq(struct tpm_chip *chip, u32 intmask)
> if (!original_int_vec) {
> if (IS_ENABLED(CONFIG_X86))
> for (i = 3; i <= 15; i++)
> - if (!tpm_tis_probe_irq_single(chip, intmask, 0,
> - i))
> + if (!tpm_tis_probe_irq_single(chip, 0, i))
> return;
> - } else if (!tpm_tis_probe_irq_single(chip, intmask, 0,
> - original_int_vec))
> + } else if (!tpm_tis_probe_irq_single(chip, 0, original_int_vec))
> return;
> }
>
> @@ -1030,8 +1104,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
> }
>
> if (irq) {
> - tpm_tis_probe_irq_single(chip, intmask, IRQF_SHARED,
> - irq);
> + tpm_tis_probe_irq_single(chip, IRQF_SHARED, irq);
> if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) {
> dev_err(&chip->dev, FW_BUG
> "TPM interrupt not working, polling instead\n");
> @@ -1039,7 +1112,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
> disable_interrupts(chip);
> }
> } else {
> - tpm_tis_probe_irq(chip, intmask);
> + tpm_tis_probe_irq(chip);
> }
> }
>
> @@ -1065,12 +1138,23 @@ EXPORT_SYMBOL_GPL(tpm_tis_core_init);
> static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
> {
> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> - u32 intmask;
> int rc;
>
> if (chip->ops->clk_enable != NULL)
> chip->ops->clk_enable(chip, true);
>
> + /*
> + * must have the locality before we can enable interrupts, so
> + * poll for the locality being ready
> + */
> + chip->flags &= ~TPM_CHIP_FLAG_IRQ;
> + if (request_locality(chip, 0) != 0) {
> + dev_err(&chip->dev, "Failed to enable interrupts after suspend\n");
> + goto out;
> + }
> + chip->flags |= TPM_CHIP_FLAG_IRQ;
> +
> +
> /* reenable interrupts that device may have lost or
> * BIOS/firmware may have disabled
> */
> @@ -1078,17 +1162,10 @@ static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
> if (rc < 0)
> goto out;
>
> - rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
> - if (rc < 0)
> - goto out;
> -
> - intmask |= TPM_INTF_CMD_READY_INT
> - | TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_DATA_AVAIL_INT
> - | TPM_INTF_STS_VALID_INT | TPM_GLOBAL_INT_ENABLE;
> + tpm_tis_enable_interrupt(chip, TPM_INTF_LOCALITY_CHANGE_INT);
>
> - tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
> -
> -out:
> + out:
> + release_locality(chip, 0);
> if (chip->ops->clk_enable != NULL)
> chip->ops->clk_enable(chip, false);
