tpm_tis: Add a check for invalid status (55707d53) · Commits · 戴 / test

Some TIS based TPMs can return 0xff to status reads if the locality hasn't been properly requested. Detect this condition by checking the bits that the TIS spec specifies must return zero are clear and return zero in that case. Also drop a warning so the problem can be identified in the calling path and fixed (usually a missing try_get_ops()). Signed-off-by:

James Bottomley <James.Bottomley@HansenPartnership.com> Reviewed-by:

Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by:

Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

drivers/char/tpm/tpm_tis_core.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -239,6 +239,17 @@ static u8 tpm_tis_status(struct tpm_chip *chip)
		if (rc < 0)
		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");
		return 0;
		}

		return status;
		}

drivers/char/tpm/tpm_tis_core.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -34,6 +34,7 @@ enum tis_status {
		TPM_STS_GO = 0x20,
		TPM_STS_DATA_AVAIL = 0x10,
		TPM_STS_DATA_EXPECT = 0x08,
		TPM_STS_READ_ZERO = 0x23, /* bits that must be zero on read */
		};

		enum tis_int_flags {

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