Re: [PATCH v4 RESEND] tpm,tpm_tis: Disable interrupts after 1000 unhandled IRQs

[Lino Sanfilippo]

On 14.07.23 05:39, Jarkko Sakkinen wrote:
> On Thu Jul 13, 2023 at 7:01 PM UTC, Lino Sanfilippo wrote:
>> After activation of interrupts for TPM TIS drivers 0-day reports an
>> interrupt storm on an Inspur NF5180M6 server.
>>
>> Fix this by detecting the storm and falling back to polling:
>> Count the number of unhandled interrupts within a 10 ms time interval. In
>> case that more than 1000 were unhandled deactivate interrupts entirely,
>> deregister the handler and use polling instead.
>>
>> Also print a note to point to the tpm_tis_dmi_table.
>>
>> Since the interrupt deregistration function devm_free_irq() waits for all
>> interrupt handlers to finish, only trigger a worker in the interrupt
>> handler and do the unregistration in the worker to avoid a deadlock.
>>
>> Note: the storm detection logic equals the implementation in
>> note_interrupt() which uses timestamps and counters stored in struct
>> irq_desc. Since this structure is private to the generic interrupt core
>> the TPM TIS core uses its own timestamps and counters. Furthermore the TPM
>> interrupt handler always returns IRQ_HANDLED to prevent the generic
>> interrupt core from processing the interrupt storm.
>>
>> Fixes: e644b2f498d2 ("tpm, tpm_tis: Enable interrupt test")
>> Reported-by: kernel test robot <yujie.liu@xxxxxxxxx>
>> Closes: https://lore.kernel.org/oe-lkp/202305041325.ae8b0c43-yujie.liu@xxxxxxxxx/
>> Suggested-by: Lukas Wunner <lukas@xxxxxxxxx>
>> Signed-off-by: Lino Sanfilippo <l.sanfilippo@xxxxxxxxxx>
>> ---
>>  drivers/char/tpm/tpm_tis_core.c | 103 +++++++++++++++++++++++++++-----
>>  drivers/char/tpm/tpm_tis_core.h |   4 ++
>>  2 files changed, 92 insertions(+), 15 deletions(-)
>>
>> Resending the patch due to several bounce messages for the first attempt.
>>
>> Changes to v3 (all requested by Jarko):
>> - remove all inline comments
>> - rename tpm_tis_reenable_polling() to tpm_tis_revert_interrupts()
>> - rename tpm_tis_check_for_interrupt_storm() to tpm_tis_update_unhandled_irqs()
>> - rename label "unhandled" to "err"
>> - add Fixes: tag
>>
>> Changes to v2:
>> - use define for max number of unhandles irqs(requested by Jarko)
>> - rename intmask to int_mask (requested by Jarko)
>> - rephrased short summary (requested by Jarko)
>> - rename disable_interrupts to tpm_tis_disable_interrupts (requested by Jarko)
>> - print info message concerning adding an entry to tpm_tis_dmi_table
>>   (suggested by Jerry)
>> - amended commit message
>> - handle failure of locality request by returning IRQ_NONE
>> - dont take and release locality in __tpm_tis_disable_interrupts but in its
>> caller
>>
>> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
>> index 558144fa707a..88a5384c09c0 100644
>> --- a/drivers/char/tpm/tpm_tis_core.c
>> +++ b/drivers/char/tpm/tpm_tis_core.c
>> @@ -24,9 +24,12 @@
>>  #include <linux/wait.h>
>>  #include <linux/acpi.h>
>>  #include <linux/freezer.h>
>> +#include <linux/dmi.h>
>>  #include "tpm.h"
>>  #include "tpm_tis_core.h"
>>
>> +#define TPM_TIS_MAX_UNHANDLED_IRQS	1000
>> +
>>  static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value);
>>
>>  static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
>> @@ -468,25 +471,29 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
>>  	return rc;
>>  }
>>
>> -static void disable_interrupts(struct tpm_chip *chip)
>> +static void __tpm_tis_disable_interrupts(struct tpm_chip *chip)
>> +{
>> +	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
>> +	u32 int_mask = 0;
>> +
>> +	tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &int_mask);
>> +	int_mask &= ~TPM_GLOBAL_INT_ENABLE;
>> +	tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), int_mask);
>> +
>> +	chip->flags &= ~TPM_CHIP_FLAG_IRQ;
>> +}
>> +
>> +static void tpm_tis_disable_interrupts(struct tpm_chip *chip)
>>  {
>>  	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
>> -	u32 intmask;
>> -	int rc;
>>
>>  	if (priv->irq == 0)
>>  		return;
>>
>> -	rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
>> -	if (rc < 0)
>> -		intmask = 0;
>> -
>> -	intmask &= ~TPM_GLOBAL_INT_ENABLE;
>> -	rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
>> +	__tpm_tis_disable_interrupts(chip);
>>
>>  	devm_free_irq(chip->dev.parent, priv->irq, chip);
>>  	priv->irq = 0;
>> -	chip->flags &= ~TPM_CHIP_FLAG_IRQ;
>>  }
>>
>>  /*
>> @@ -552,7 +559,7 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
>>  	if (!test_bit(TPM_TIS_IRQ_TESTED, &priv->flags))
>>  		tpm_msleep(1);
>>  	if (!test_bit(TPM_TIS_IRQ_TESTED, &priv->flags))
>> -		disable_interrupts(chip);
>> +		tpm_tis_disable_interrupts(chip);
>>  	set_bit(TPM_TIS_IRQ_TESTED, &priv->flags);
>>  	return rc;
>>  }
>> @@ -752,6 +759,57 @@ static bool tpm_tis_req_canceled(struct tpm_chip *chip, u8 status)
>>  	return status == TPM_STS_COMMAND_READY;
>>  }
>>
>> +static irqreturn_t tpm_tis_revert_interrupts(struct tpm_chip *chip)
>> +{
>> +	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
>> +	const char *product;
>> +	const char *vendor;
>> +
>> +	dev_warn(&chip->dev, FW_BUG
>> +		 "TPM interrupt storm detected, polling instead\n");
>> +
>> +	vendor = dmi_get_system_info(DMI_SYS_VENDOR);
>> +	product = dmi_get_system_info(DMI_PRODUCT_VERSION);
>> +
>> +	if (vendor && product) {
>> +		dev_info(&chip->dev,
>> +			"Consider adding the following entry to tpm_tis_dmi_table:\n");
>> +		dev_info(&chip->dev, "\tDMI_SYS_VENDOR: %s\n", vendor);
>> +		dev_info(&chip->dev, "\tDMI_PRODUCT_VERSION: %s\n", product);
>> +	}
>> +
>> +	if (tpm_tis_request_locality(chip, 0) != 0)
>> +		return IRQ_NONE;
>> +
>> +	__tpm_tis_disable_interrupts(chip);
>> +	tpm_tis_relinquish_locality(chip, 0);
>> +
>> +	schedule_work(&priv->free_irq_work);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static irqreturn_t tpm_tis_update_unhandled_irqs(struct tpm_chip *chip)
>> +{
>> +	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
>> +	irqreturn_t irqret = IRQ_HANDLED;
>> +
>> +	if (!(chip->flags & TPM_CHIP_FLAG_IRQ))
>> +		return IRQ_HANDLED;
>> +
>> +	if (time_after(jiffies, priv->last_unhandled_irq + HZ/10))
>> +		priv->unhandled_irqs = 1;
>> +	else
>> +		priv->unhandled_irqs++;
>> +
>> +	priv->last_unhandled_irq = jiffies;
>> +
>> +	if (priv->unhandled_irqs > TPM_TIS_MAX_UNHANDLED_IRQS)
>> +		irqret = tpm_tis_revert_interrupts(chip);
>> +
>> +	return irqret;
>> +}
>> +
>>  static irqreturn_t tis_int_handler(int dummy, void *dev_id)
>>  {
>>  	struct tpm_chip *chip = dev_id;
>> @@ -761,10 +819,10 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
>>
>>  	rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
>>  	if (rc < 0)
>> -		return IRQ_NONE;
>> +		goto err;
>>
>>  	if (interrupt == 0)
>> -		return IRQ_NONE;
>> +		goto err;
>>
>>  	set_bit(TPM_TIS_IRQ_TESTED, &priv->flags);
>>  	if (interrupt & TPM_INTF_DATA_AVAIL_INT)
>> @@ -780,10 +838,13 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
>>  	rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), interrupt);
>>  	tpm_tis_relinquish_locality(chip, 0);
>>  	if (rc < 0)
>> -		return IRQ_NONE;
>> +		goto err;
>>
>>  	tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
>>  	return IRQ_HANDLED;
>> +
>> +err:
>> +	return tpm_tis_update_unhandled_irqs(chip);
>>  }
>>
>>  static void tpm_tis_gen_interrupt(struct tpm_chip *chip)
>> @@ -804,6 +865,15 @@ static void tpm_tis_gen_interrupt(struct tpm_chip *chip)
>>  		chip->flags &= ~TPM_CHIP_FLAG_IRQ;
>>  }
>>
>> +static void tpm_tis_free_irq_func(struct work_struct *work)
>> +{
>> +	struct tpm_tis_data *priv = container_of(work, typeof(*priv), free_irq_work);
>> +	struct tpm_chip *chip = priv->chip;
>> +
>> +	devm_free_irq(chip->dev.parent, priv->irq, chip);
>> +	priv->irq = 0;
>> +}
>> +
>>  /* Register the IRQ and issue a command that will cause an interrupt. If an
>>   * irq is seen then leave the chip setup for IRQ operation, otherwise reverse
>>   * everything and leave in polling mode. Returns 0 on success.
>> @@ -816,6 +886,7 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
>>  	int rc;
>>  	u32 int_status;
>>
>> +	INIT_WORK(&priv->free_irq_work, tpm_tis_free_irq_func);
>>
>>  	rc = devm_request_threaded_irq(chip->dev.parent, irq, NULL,
>>  				       tis_int_handler, IRQF_ONESHOT | flags,
>> @@ -918,6 +989,7 @@ void tpm_tis_remove(struct tpm_chip *chip)
>>  		interrupt = 0;
>>
>>  	tpm_tis_write32(priv, reg, ~TPM_GLOBAL_INT_ENABLE & interrupt);
>> +	flush_work(&priv->free_irq_work);
>>
>>  	tpm_tis_clkrun_enable(chip, false);
>>
>> @@ -1021,6 +1093,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
>>  	chip->timeout_b = msecs_to_jiffies(TIS_TIMEOUT_B_MAX);
>>  	chip->timeout_c = msecs_to_jiffies(TIS_TIMEOUT_C_MAX);
>>  	chip->timeout_d = msecs_to_jiffies(TIS_TIMEOUT_D_MAX);
>> +	priv->chip = chip;
>>  	priv->timeout_min = TPM_TIMEOUT_USECS_MIN;
>>  	priv->timeout_max = TPM_TIMEOUT_USECS_MAX;
>>  	priv->phy_ops = phy_ops;
>> @@ -1179,7 +1252,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
>>  			rc = tpm_tis_request_locality(chip, 0);
>>  			if (rc < 0)
>>  				goto out_err;
>> -			disable_interrupts(chip);
>> +			tpm_tis_disable_interrupts(chip);
>>  			tpm_tis_relinquish_locality(chip, 0);
>>  		}
>>  	}
>> diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
>> index 610bfadb6acf..b1a169d7d1ca 100644
>> --- a/drivers/char/tpm/tpm_tis_core.h
>> +++ b/drivers/char/tpm/tpm_tis_core.h
>> @@ -91,11 +91,15 @@ enum tpm_tis_flags {
>>  };
>>
>>  struct tpm_tis_data {
>> +	struct tpm_chip *chip;
>>  	u16 manufacturer_id;
>>  	struct mutex locality_count_mutex;
>>  	unsigned int locality_count;
>>  	int locality;
>>  	int irq;
>> +	struct work_struct free_irq_work;
>> +	unsigned long last_unhandled_irq;
>> +	unsigned int unhandled_irqs;
>>  	unsigned int int_mask;
>>  	unsigned long flags;
>>  	void __iomem *ilb_base_addr;
>>
>> base-commit: 6995e2de6891c724bfeb2db33d7b87775f913ad1
>> --
>> 2.25.1
>
> Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
>
> Looks very good, thank you.


Great, thanks a lot for the review(s)!

Regards,
Lino