From 805fa88e0780b7ce1cc9b649dd91a0a7164c6eb4 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <matthewgarrett@google.com>
Date: Thu, 2 Jan 2020 13:55:18 -0800
Subject: [PATCH] tpm: Don't make log failures fatal
Git-commit: 805fa88e0780b7ce1cc9b649dd91a0a7164c6eb4
Patch-mainline: v5.7-rc1
References: git-fixes

If a TPM is in disabled state, it's reasonable for it to have an empty
log. Bailing out of probe in this case means that the PPI interface
isn't available, so there's no way to then enable the TPM from the OS.
In general it seems reasonable to ignore log errors - they shouldn't
interfere with any other TPM functionality.

Signed-off-by: Matthew Garrett <matthewgarrett@google.com>
Cc: stable@vger.kernel.org # 4.19.x
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/char/tpm/eventlog/common.c | 12 ++++--------
 drivers/char/tpm/tpm-chip.c        |  4 +---
 drivers/char/tpm/tpm.h             |  2 +-
 3 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/char/tpm/eventlog/common.c b/drivers/char/tpm/eventlog/common.c
index 7a0fca659b6a..7460f230bae4 100644
--- a/drivers/char/tpm/eventlog/common.c
+++ b/drivers/char/tpm/eventlog/common.c
@@ -99,11 +99,8 @@ static int tpm_read_log(struct tpm_chip *chip)
  *
  * If an event log is found then the securityfs files are setup to
  * export it to userspace, otherwise nothing is done.
- *
- * Returns -ENODEV if the firmware has no event log or securityfs is not
- * supported.
  */
-int tpm_bios_log_setup(struct tpm_chip *chip)
+void tpm_bios_log_setup(struct tpm_chip *chip)
 {
 	const char *name = dev_name(&chip->dev);
 	unsigned int cnt;
@@ -112,7 +109,7 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
 
 	rc = tpm_read_log(chip);
 	if (rc < 0)
-		return rc;
+		return;
 	log_version = rc;
 
 	cnt = 0;
@@ -158,13 +155,12 @@ int tpm_bios_log_setup(struct tpm_chip *chip)
 		cnt++;
 	}
 
-	return 0;
+	return;
 
 err:
-	rc = PTR_ERR(chip->bios_dir[cnt]);
 	chip->bios_dir[cnt] = NULL;
 	tpm_bios_log_teardown(chip);
-	return rc;
+	return;
 }
 
 void tpm_bios_log_teardown(struct tpm_chip *chip)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 3d6d394a8661..58073836b555 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -596,9 +596,7 @@ int tpm_chip_register(struct tpm_chip *chip)
 
 	tpm_sysfs_add_device(chip);
 
-	rc = tpm_bios_log_setup(chip);
-	if (rc != 0 && rc != -ENODEV)
-		return rc;
+	tpm_bios_log_setup(chip);
 
 	tpm_add_ppi(chip);
 
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 5620747da0cf..2b2c225e1190 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -235,7 +235,7 @@ int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u8 *cmd,
 int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space, void *buf,
 		      size_t *bufsiz);
 
-int tpm_bios_log_setup(struct tpm_chip *chip);
+void tpm_bios_log_setup(struct tpm_chip *chip);
 void tpm_bios_log_teardown(struct tpm_chip *chip);
 int tpm_dev_common_init(void);
 void tpm_dev_common_exit(void);
-- 
2.16.4