diff options
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/tpm/tpm-chip.c | 36 | ||||
| -rw-r--r-- | drivers/char/tpm/tpm-sysfs.c | 5 |
2 files changed, 41 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index a017ccd8cc3b..9ff853229957 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -130,6 +130,41 @@ static void tpm_dev_release(struct device *dev) kfree(chip); } + +/** + * tpm_class_shutdown() - prepare the TPM device for loss of power. + * @dev: device to which the chip is associated. + * + * Issues a TPM2_Shutdown command prior to loss of power, as required by the + * TPM 2.0 spec. + * Then, calls bus- and device- specific shutdown code. + * + * XXX: This codepath relies on the fact that sysfs is not enabled for + * TPM2: sysfs uses an implicit lock on chip->ops, so this could race if TPM2 + * has sysfs support enabled before TPM sysfs's implicit locking is fixed. + */ +static int tpm_class_shutdown(struct device *dev) +{ + struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev); + + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + down_write(&chip->ops_sem); + tpm2_shutdown(chip, TPM2_SU_CLEAR); + chip->ops = NULL; + up_write(&chip->ops_sem); + } + /* Allow bus- and device-specific code to run. Note: since chip->ops + * is NULL, more-specific shutdown code will not be able to issue TPM + * commands. + */ + if (dev->bus && dev->bus->shutdown) + dev->bus->shutdown(dev); + else if (dev->driver && dev->driver->shutdown) + dev->driver->shutdown(dev); + return 0; +} + + /** * tpm_chip_alloc() - allocate a new struct tpm_chip instance * @pdev: device to which the chip is associated @@ -168,6 +203,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev, device_initialize(&chip->dev); chip->dev.class = tpm_class; + chip->dev.class->shutdown = tpm_class_shutdown; chip->dev.release = tpm_dev_release; chip->dev.parent = pdev; chip->dev.groups = chip->groups; diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c index 47005840c42c..edf8c59a6ed4 100644 --- a/drivers/char/tpm/tpm-sysfs.c +++ b/drivers/char/tpm/tpm-sysfs.c @@ -285,6 +285,11 @@ static const struct attribute_group tpm_dev_group = { void tpm_sysfs_add_device(struct tpm_chip *chip) { + /* XXX: If you wish to remove this restriction, you must first update + * tpm_sysfs to explicitly lock chip->ops. + */ + if (chip->flags & TPM_CHIP_FLAG_TPM2) + return; /* The sysfs routines rely on an implicit tpm_try_get_ops, device_del * is called before ops is null'd and the sysfs core synchronizes this * removal so that no callbacks are running or can run again |