linux-kernel - [PATCH] tpm: turn on TPM on suspend for TPM 1.x

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Date:   Fri, 22 Mar 2019 12:51:20 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     linux-integrity@...r.kernel.org
Cc:     linux-security-module@...r.kernel.org, pauldzim@...il.com,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] tpm: turn on TPM on suspend for TPM 1.x

tpm_chip_start/stop() should be also called for TPM 1.x devices on
suspend. Add that functionality back. Do not lock the chip because
it is unnecessary as there are no multiple threads using it when
doing the suspend.

Fixes: a3fbfae82b4c ("tpm: take TPM chip power gating out of tpm_transmit()")
Reported-by: Paul Zimmerman <pauldzim@...il.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
---
 drivers/char/tpm/tpm-interface.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 83ece5639f86..ae1030c9b086 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -402,15 +402,13 @@ int tpm_pm_suspend(struct device *dev)
 	if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
 		return 0;
 
-	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
-		mutex_lock(&chip->tpm_mutex);
-		if (!tpm_chip_start(chip)) {
+	if (!tpm_chip_start(chip)) {
+		if (chip->flags & TPM_CHIP_FLAG_TPM2)
 			tpm2_shutdown(chip, TPM2_SU_STATE);
-			tpm_chip_stop(chip);
-		}
-		mutex_unlock(&chip->tpm_mutex);
-	} else {
-		rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);
+		else
+			rc = tpm1_pm_suspend(chip, tpm_suspend_pcr);
+
+		tpm_chip_stop(chip);
 	}
 
 	return rc;
-- 
2.19.1