tpm: fix suspend/resume paths for TPM 2.0

Fixed suspend/resume paths for TPM 2.0 and consolidated all the
associated code to the tpm_pm_suspend() and tpm_pm_resume()
functions. Resume path should be handled by the firmware, i.e.
Startup(CLEAR) for hibernate and Startup(STATE) for suspend.

There might be some non-PC embedded devices in the future where
Startup() is not the handled by the FW but fixing the code for
those IMHO should be postponed until there is hardware available
to test the fixes although extra Startup in the driver code is
essentially a NOP.

Added Shutdown(CLEAR) to the remove paths of TIS and CRB drivers.
Changed tpm2_shutdown() to a void function because there isn't
much you can do except print an error message if this fails with
a system error.

Fixes: aec04cbdf723 ("tpm: TPM 2.0 FIFO Interface")
Fixes: 30fc8d138e91 ("tpm: TPM 2.0 CRB Interface")
[phuewe: both did send TPM_Shutdown on resume which 'disables' the TPM
and did not send TPM2_Shutdown on teardown which leads some TPM2.0 to
believe there was an attack (no TPM2_Shutdown = no orderly shutdown =
attack)]

Reported-by: Peter Hüwe <PeterHuewe@gmx.de>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Scot Doyle <lkml14@scotdoyle.com>
Reviewed-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>

1 files changed, 11 insertions, 8 deletions

diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 1abe6502219f..f2f38a5ee632 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -456,20 +456,23 @@ static const struct tpm_input_header tpm2_shutdown_header = {
  * @chip:		TPM chip to use.
  * @shutdown_type	shutdown type. The value is either
  *			TPM_SU_CLEAR or TPM_SU_STATE.
- *
- * 0 is returned when the operation is successful. If a negative number is
- * returned it remarks a POSIX error code. If a positive number is returned
- * it remarks a TPM error.
  */
-int tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
+void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
 {
 	struct tpm2_cmd cmd;
+	int rc;
 
 	cmd.header.in = tpm2_shutdown_header;
-
 	cmd.params.startup_in.startup_type = cpu_to_be16(shutdown_type);
-	return tpm_transmit_cmd(chip, &cmd, sizeof(cmd),
-				"stopping the TPM");
+
+	rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), "stopping the TPM");
+
+	/* In places where shutdown command is sent there's no much we can do
+	 * except print the error code on a system failure.
+	 */
+	if (rc < 0)
+		dev_warn(chip->pdev, "transmit returned %d while stopping the TPM",
+			 rc);
 }
 EXPORT_SYMBOL_GPL(tpm2_shutdown);