Re: [PATCH 1/2] tpm, tpm_tis: Handle interrupt storm

Jarkko Sakkinen
2023-05-24T15:30:36Z

On Wed May 24, 2023 at 6:58 AM EEST, Jarkko Sakkinen wrote:
> > rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
> > if (rc < 0)
> > - return IRQ_NONE;
> > + goto unhandled;
> >
> > if (interrupt == 0)
> > - return IRQ_NONE;
> > + goto unhandled;
> >
> > set_bit(TPM_TIS_IRQ_TESTED, &priv->flags);
> > if (interrupt & TPM_INTF_DATA_AVAIL_INT)
> > @@ -780,10 +829,14 @@ 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 unhandled;
> >
> > tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
> > return IRQ_HANDLED;
> > +
> > +unhandled:
> > + tpm_tis_process_unhandled_interrupt(chip);
> > + return IRQ_HANDLED;
> > }

Some minor glitches I noticed.

You could simplify the flow by making the helper to return IRQ_NONE.

E.g.

tpm_tis_relinquish_locality(chip, 0);
if (rc < 0)
return tpm_tis_process_unhandled_interrupt(chip);

I'd recommend changing the function name simply tpm_tis_rollback_interrupt().

Also tpm_tis_handle_irq_storm() is a pretty bad function name
because handle also can mean anything. You are resetting to the
polling mode, right?

So perhaps that could be e.g. tpm_tis_reenable_polling? I'm open
for any other name but it really needs to give a hint what the
function does.

BR, Jarkko