On Fri, Mar 07, 2025 at 04:36:12PM +0000, Jonathan McDowell wrote: > On Fri, Mar 07, 2025 at 12:23:11AM +0200, Jarkko Sakkinen wrote: > > On Thu, Mar 06, 2025 at 09:00:56AM +0000, Jonathan McDowell wrote: > > > From: Jonathan McDowell <noodles@xxxxxxxx> > > > > > > Some Infineon devices have a issue where the status register will get > > > stuck with a quick REQUEST_USE / COMMAND_READY sequence. This is not > > > simply a matter of requiring a longer timeout; the work around is to > > > retry the command submission. Add appropriate logic to do this in the > > > send path. > > > > > > This is fixed in later firmware revisions, but those are not always > > > available, and cannot generally be easily updated from outside a > > > firmware environment. > > > > > > Testing has been performed with a simple repeated loop of doing a > > > TPM2_CC_GET_CAPABILITY for TPM_CAP_PROP_MANUFACTURER using the Go code > > > at: > > > > > > https://the.earth.li/~noodles/tpm-stuff/timeout-reproducer-simple.go > > > > > > It can take several hours to reproduce, and millions of operations. > > > > > > Signed-off-by: Jonathan McDowell <noodles@xxxxxxxx> > > > --- > > > drivers/char/tpm/tpm_tis_core.c | 17 ++++++++++++++--- > > > drivers/char/tpm/tpm_tis_core.h | 1 + > > > include/linux/tpm.h | 1 + > > > 3 files changed, 16 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > > > index 167d71747666..e4eae206a353 100644 > > > --- a/drivers/char/tpm/tpm_tis_core.c > > > +++ b/drivers/char/tpm/tpm_tis_core.c > > > @@ -464,7 +464,10 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) > > > > > > if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, > > > &priv->int_queue, false) < 0) { > > > - rc = -ETIME; > > > + if (test_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags)) > > > + rc = -EAGAIN; > > > + else > > > + rc = -ETIME; > > > goto out_err; > > > } > > > status = tpm_tis_status(chip); > > > @@ -481,7 +484,10 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) > > > > > > if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, > > > &priv->int_queue, false) < 0) { > > > - rc = -ETIME; > > > + if (test_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags)) > > > + rc = -EAGAIN; > > > + else > > > + rc = -ETIME; > > > > I'd encapsulate this inside wait_for_tpm_stat(). > > I think that gets a bit more complicated; this is an errata in the send > command path, for a stuck VALID bit, and the fix is to restart the whole > command send (i.e. we need to kick the TPM with tpm_tis_ready() etc). > I'm not sure returning EAGAIN in wait_for_tpm_stat() then makes > tpm_tis_send_data() any simpler. OK, it is a fair argument. Let's keep it as it is. > > > > goto out_err; > > > } > > > status = tpm_tis_status(chip); > > > @@ -546,9 +552,11 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len) > > > if (rc >= 0) > > > /* Data transfer done successfully */ > > > break; > > > - else if (rc != -EIO) > > > + else if (rc != EAGAIN && rc != -EIO) > > > /* Data transfer failed, not recoverable */ > > > return rc; > > > + > > > + usleep_range(priv->timeout_min, priv->timeout_max); > > > } > > > > > > /* go and do it */ > > > @@ -1144,6 +1152,9 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > > > priv->timeout_max = TIS_TIMEOUT_MAX_ATML; > > > } > > > > > > + if (priv->manufacturer_id == TPM_VID_IFX) > > > + set_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags); > > > + > > > if (is_bsw()) { > > > priv->ilb_base_addr = ioremap(INTEL_LEGACY_BLK_BASE_ADDR, > > > ILB_REMAP_SIZE); > > > diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h > > > index 690ad8e9b731..ce97b58dc005 100644 > > > --- a/drivers/char/tpm/tpm_tis_core.h > > > +++ b/drivers/char/tpm/tpm_tis_core.h > > > @@ -89,6 +89,7 @@ enum tpm_tis_flags { > > > TPM_TIS_INVALID_STATUS = 1, > > > TPM_TIS_DEFAULT_CANCELLATION = 2, > > > TPM_TIS_IRQ_TESTED = 3, > > > + TPM_TIS_STATUS_WORKAROUND = 4, > > > > TPM_TIS_TIMEOUT_AGAIN or maybe *_REPEAT? The current name does > > not tell anything. > > Yeah, TPM_TIS_STATUS_VALID_RETRY is perhaps clearer; it's not a timeout, > and we're looking to do a retry based on STS_VALID. WFM > > > > }; > > > > > > struct tpm_tis_data { > > > diff --git a/include/linux/tpm.h b/include/linux/tpm.h > > > index 20a40ade8030..6c3125300c00 100644 > > > --- a/include/linux/tpm.h > > > +++ b/include/linux/tpm.h > > > @@ -335,6 +335,7 @@ enum tpm2_cc_attrs { > > > #define TPM_VID_WINBOND 0x1050 > > > #define TPM_VID_STM 0x104A > > > #define TPM_VID_ATML 0x1114 > > > +#define TPM_VID_IFX 0x15D1 > > > > > > enum tpm_chip_flags { > > > TPM_CHIP_FLAG_BOOTSTRAPPED = BIT(0), > > J. > > -- > ... "What's the philosophical difference between a killfile and the > automoderation?" "A killfile throws away good posts. Automoderation > throws away bad posts." -- Jonathan H N Chin to Calle Dybedahl BR, Jarkko
