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: aec04cbdf7 ("tpm: TPM 2.0 FIFO Interface")
Fixes: 30fc8d138e ("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>

drivers/char/tpm/tpm-interface.c

@@ -901,8 +901,10 @@ int tpm_pm_suspend(struct device *dev)
 	if (chip == NULL)
 		return -ENODEV;
 
-	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		return tpm2_shutdown(chip, TPM2_SU_CLEAR);
+	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+		tpm2_shutdown(chip, TPM2_SU_STATE);
+		return 0;
+	}
 
 	/* for buggy tpm, flush pcrs with extend to selected dummy */
 	if (tpm_suspend_pcr) {

drivers/char/tpm/tpm.h

@@ -432,7 +432,7 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,
 			u32 *value, const char *desc);
 
 extern int tpm2_startup(struct tpm_chip *chip, u16 startup_type);
-extern int tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type);
+extern void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type);
 extern unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *, u32);
 extern int tpm2_do_selftest(struct tpm_chip *chip);
 extern int tpm2_gen_interrupt(struct tpm_chip *chip, bool quiet);

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);
 

drivers/char/tpm/tpm_crb.c

@@ -95,21 +95,7 @@ struct crb_priv {
 	u8 __iomem *rsp;
 };
 
-#ifdef CONFIG_PM_SLEEP
-static int crb_resume(struct device *dev)
-{
-	int rc;
-	struct tpm_chip *chip = dev_get_drvdata(dev);
-
-	rc = tpm2_shutdown(chip, TPM2_SU_STATE);
-	if (!rc)
-		rc = tpm2_do_selftest(chip);
-
-	return rc;
-}
-#endif
-
-static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, crb_resume);
+static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
 
 static u8 crb_status(struct tpm_chip *chip)
 {
@@ -326,6 +312,10 @@ static int crb_acpi_remove(struct acpi_device *device)
 	struct tpm_chip *chip = dev_get_drvdata(dev);
 
 	tpm_chip_unregister(chip);
+
+	if (chip->flags & TPM_CHIP_FLAG_TPM2)
+		tpm2_shutdown(chip, TPM2_SU_CLEAR);
+
 	return 0;
 }
 

drivers/char/tpm/tpm_tis.c

@@ -588,6 +588,9 @@ MODULE_PARM_DESC(interrupts, "Enable interrupts");
 
 static void tpm_tis_remove(struct tpm_chip *chip)
 {
+	if (chip->flags & TPM_CHIP_FLAG_TPM2)
+		tpm2_shutdown(chip, TPM2_SU_CLEAR);
+
 	iowrite32(~TPM_GLOBAL_INT_ENABLE &
 		  ioread32(chip->vendor.iobase +
 			   TPM_INT_ENABLE(chip->vendor.
@@ -865,25 +868,22 @@ static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
 static int tpm_tis_resume(struct device *dev)
 {
 	struct tpm_chip *chip = dev_get_drvdata(dev);
-	int ret = 0;
+	int ret;
 
 	if (chip->vendor.irq)
 		tpm_tis_reenable_interrupts(chip);
 
-	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
-		/* NOP if firmware properly does this. */
-		tpm2_startup(chip, TPM2_SU_STATE);
+	ret = tpm_pm_resume(dev);
+	if (ret)
+		return ret;
 
-		ret = tpm2_shutdown(chip, TPM2_SU_STATE);
-		if (!ret)
-			ret = tpm2_do_selftest(chip);
-	} else {
-		ret = tpm_pm_resume(dev);
-		if (!ret)
-			tpm_do_selftest(chip);
-	}
+	/* TPM 1.2 requires self-test on resume. This function actually returns
+	 * an error code but for unknown reason it isn't handled.
+	 */
+	if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
+		tpm_do_selftest(chip);
 
-	return ret;
+	return 0;
 }
 #endif