[PATCH v3] tpm: fix crash in tpm_tis deinitialization

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

rmmod crashes the driver because tpm_chip_unregister() already sets ops
to NULL. This commit fixes the issue by moving tpm2_shutdown() to
tpm_chip_unregister(). This commit is also cleanup because it removes
duplicate code from tpm_crb and tpm_tis to the core.

v2: make sending shutdown command atomic with nulling ops
v3: forgot to amend updates, sorry :(

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Fixes: 4d3eac5e156a ("tpm: Provide strong locking for device removal")
---
 drivers/char/tpm/tpm-chip.c | 1 +
 drivers/char/tpm/tpm.h      | 2 +-
 drivers/char/tpm/tpm2-cmd.c | 1 -
 drivers/char/tpm/tpm_crb.c  | 3 ---
 drivers/char/tpm/tpm_tis.c  | 3 ---
 5 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index f62c851..5bc530c 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -269,6 +269,7 @@ static void tpm_del_char_device(struct tpm_chip *chip)
 
 	/* Make the driver uncallable. */
 	down_write(&chip->ops_sem);
+	tpm2_shutdown(chip, TPM2_SU_CLEAR);
 	chip->ops = NULL;
 	up_write(&chip->ops_sem);
 }
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 8bc6fb8..1156b34 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -522,7 +522,7 @@ 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 void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type);
+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);
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 9ce8031..a1673dc 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -773,7 +773,6 @@ void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
 		dev_warn(&chip->dev, "transmit returned %d while stopping the TPM",
 			 rc);
 }
-EXPORT_SYMBOL_GPL(tpm2_shutdown);
 
 /*
  * tpm2_calc_ordinal_duration() - maximum duration for a command
diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
index 20155d5..c31b5a7 100644
--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c
@@ -341,9 +341,6 @@ static int crb_acpi_remove(struct acpi_device *device)
 	struct device *dev = &device->dev;
 	struct tpm_chip *chip = dev_get_drvdata(dev);
 
-	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		tpm2_shutdown(chip, TPM2_SU_CLEAR);
-
 	tpm_chip_unregister(chip);
 
 	return 0;
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 1e45e73..a6b2d46 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -681,9 +681,6 @@ static void tpm_tis_remove(struct tpm_chip *chip)
 	struct priv_data *priv = dev_get_drvdata(&chip->dev);
 	void __iomem *reg = priv->iobase + TPM_INT_ENABLE(priv->locality);
 
-	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		tpm2_shutdown(chip, TPM2_SU_CLEAR);
-
 	iowrite32(~TPM_GLOBAL_INT_ENABLE & ioread32(reg), reg);
 	release_locality(chip, priv->locality, 1);
 }
-- 
2.7.4