Do not tear down the system when getting invalid status from a TPM chip. This can happen when panic-on-warn is used.

Instead, introduce TPM_TIS_INVALID_STATUS bitflag and use it to trigger once the error reporting per chip. In addition, print out the value of TPM_STS for improved forensics.

Link: https://lore.kernel.org/keyrings/YKzlTR1AzUigShtZ@kroah.com/ Fixes: 55707d531af6 ("tpm_tis: Add a check for invalid status") Cc: stable@vger.kernel.org Cc: Hans de Goede hdegoede@redhat.com Cc: Greg KH greg@kroah.com Signed-off-by: Jarkko Sakkinen jarkko@kernel.org ---

v3: * torn -> tear * A per chip flag TPM_TIS_INVALID_STATUS.

v2: Dump also stack only once.

drivers/char/tpm/tpm_tis_core.c | 25 ++++++++++++++++++------- drivers/char/tpm/tpm_tis_core.h | 3 ++- 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index 55b9d3965ae1..69579efb247b 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -196,13 +196,24 @@ static u8 tpm_tis_status(struct tpm_chip *chip) return 0;

if (unlikely((status & TPM_STS_READ_ZERO) != 0)) { - /* - * If this trips, the chances are the read is - * returning 0xff because the locality hasn't been - * acquired. Usually because tpm_try_get_ops() hasn't - * been called before doing a TPM operation. - */ - WARN_ONCE(1, "TPM returned invalid status\n"); + if (!test_and_set_bit(TPM_TIS_INVALID_STATUS, &priv->flags)) { + /* + * If this trips, the chances are the read is + * returning 0xff because the locality hasn't been + * acquired. Usually because tpm_try_get_ops() hasn't + * been called before doing a TPM operation. + */ + dev_err(&chip->dev, "invalid TPM_STS.x 0x%02x, dumping stack for forensics\n", + status); + + /* + * Dump stack for forensics, as invalid TPM_STS.x could be + * potentially triggered by impaired tpm_try_get_ops() or + * tpm_find_get_ops(). + */ + dump_stack(); + } + return 0; }

diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h index 9b2d32a59f67..b2a3c6c72882 100644 --- a/drivers/char/tpm/tpm_tis_core.h +++ b/drivers/char/tpm/tpm_tis_core.h @@ -83,6 +83,7 @@ enum tis_defaults {

enum tpm_tis_flags { TPM_TIS_ITPM_WORKAROUND = BIT(0), + TPM_TIS_INVALID_STATUS = BIT(1), };

struct tpm_tis_data { @@ -90,7 +91,7 @@ struct tpm_tis_data { int locality; int irq; bool irq_tested; - unsigned int flags; + unsigned long flags; void __iomem *ilb_base_addr; u16 clkrun_enabled; wait_queue_head_t int_queue;