tpm: Fix TPM 1.2 Shutdown sequence to prevent future TPM operations

TPM 2.0 Shutdown involve sending TPM2_Shutdown to TPM chip and disabling
future TPM operations. TPM 1.2 behavior was different, future TPM
operations weren't disabled, causing rare issues. This patch ensures
that future TPM operations are disabled.

Fixes: d1bd4a792d39 ("tpm: Issue a TPM2_Shutdown for TPM2 devices.")
Cc: stable@vger.kernel.org
Signed-off-by: Vadim Sukhomlinov <sukhomlinov@google.com>
[dianders: resolved merge conflicts with mainline]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 90325e1749fb62f8549947fa9577560ba3676c5a..d47ad10a35fe3362156fbdb15038eb4fda661a97 100644 (file)
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -289,15 +289,15 @@ static int tpm_class_shutdown(struct device *dev)
 {
        struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
 
+       down_write(&chip->ops_sem);
        if (chip->flags & TPM_CHIP_FLAG_TPM2) {
-               down_write(&chip->ops_sem);
                if (!tpm_chip_start(chip)) {
                        tpm2_shutdown(chip, TPM2_SU_CLEAR);
                        tpm_chip_stop(chip);
                }
-               chip->ops = NULL;
-               up_write(&chip->ops_sem);
        }
+       chip->ops = NULL;
+       up_write(&chip->ops_sem);
 
        return 0;
 }