Messages in this thread | | | Date | Thu, 28 Jul 2016 15:52:50 -0700 | From | Dmitry Torokhov <> | Subject | Re: [PATCH v3 1/2] tpm_tis_core: add optional max xfer size check |
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On Wed, Jul 27, 2016 at 08:49:56PM -0700, Andrey Pronin wrote: > If tpm reports a bigger burstcnt than allowed by the physical protocol, > set burstcnt to the max allowed value. > > In practice, seen in case of xfer issues (e.g. in spi interface case, > lost header causing flow control issues and wrong values returned on read > from TPM_STS). Without catching, causes the physical layer to reject xfer. > > Signed-off-by: Andrey Pronin <apronin@chromium.org> > --- > drivers/char/tpm/tpm_tis_core.c | 9 ++++++++- > drivers/char/tpm/tpm_tis_core.h | 1 + > 2 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index f22caf8..7c4fa0c 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -168,8 +168,15 @@ static int get_burstcount(struct tpm_chip *chip) > return rc; > > burstcnt = (value >> 8) & 0xFFFF; > - if (burstcnt) > + if (burstcnt) { > + if (priv->phy_ops->max_xfer_size && > + (burstcnt > priv->phy_ops->max_xfer_size)) {
This does not actually need parentheses, otehrwise:
Reviewed-by: Dmitry Torokhov <dtor@chromium.org>
> + dev_warn(&chip->dev, > + "Bad burstcnt read: %d\n", burstcnt); > + burstcnt = priv->phy_ops->max_xfer_size; > + } > return burstcnt; > + } > msleep(TPM_TIMEOUT); > } while (time_before(jiffies, stop)); > return -EBUSY; > diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h > index 9191aab..58e8b14 100644 > --- a/drivers/char/tpm/tpm_tis_core.h > +++ b/drivers/char/tpm/tpm_tis_core.h > @@ -102,6 +102,7 @@ struct tpm_tis_phy_ops { > int (*read16)(struct tpm_tis_data *data, u32 addr, u16 *result); > int (*read32)(struct tpm_tis_data *data, u32 addr, u32 *result); > int (*write32)(struct tpm_tis_data *data, u32 addr, u32 src); > + u16 max_xfer_size; > }; > > static inline int tpm_tis_read_bytes(struct tpm_tis_data *data, u32 addr, > -- > 2.6.6 >
-- Dmitry
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