linux/drivers/char/tpm/tpm-chip.c
Michal Suchanek 7521621e60 Do not disable driver and bus shutdown hook when class shutdown hook is set.
As seen from the implementation of the single class shutdown hook this
is not very sound design.

Rename the class shutdown hook to shutdown_pre to make it clear it runs
before the driver shutdown hook.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-28 18:02:46 +02:00

460 lines
11 KiB
C

/*
* Copyright (C) 2004 IBM Corporation
* Copyright (C) 2014 Intel Corporation
*
* Authors:
* Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
* Leendert van Doorn <leendert@watson.ibm.com>
* Dave Safford <safford@watson.ibm.com>
* Reiner Sailer <sailer@watson.ibm.com>
* Kylene Hall <kjhall@us.ibm.com>
*
* Maintained by: <tpmdd-devel@lists.sourceforge.net>
*
* TPM chip management routines.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
*/
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/freezer.h>
#include <linux/major.h>
#include "tpm.h"
#include "tpm_eventlog.h"
DEFINE_IDR(dev_nums_idr);
static DEFINE_MUTEX(idr_lock);
struct class *tpm_class;
struct class *tpmrm_class;
dev_t tpm_devt;
/**
* tpm_try_get_ops() - Get a ref to the tpm_chip
* @chip: Chip to ref
*
* The caller must already have some kind of locking to ensure that chip is
* valid. This function will lock the chip so that the ops member can be
* accessed safely. The locking prevents tpm_chip_unregister from
* completing, so it should not be held for long periods.
*
* Returns -ERRNO if the chip could not be got.
*/
int tpm_try_get_ops(struct tpm_chip *chip)
{
int rc = -EIO;
get_device(&chip->dev);
down_read(&chip->ops_sem);
if (!chip->ops)
goto out_lock;
return 0;
out_lock:
up_read(&chip->ops_sem);
put_device(&chip->dev);
return rc;
}
EXPORT_SYMBOL_GPL(tpm_try_get_ops);
/**
* tpm_put_ops() - Release a ref to the tpm_chip
* @chip: Chip to put
*
* This is the opposite pair to tpm_try_get_ops(). After this returns chip may
* be kfree'd.
*/
void tpm_put_ops(struct tpm_chip *chip)
{
up_read(&chip->ops_sem);
put_device(&chip->dev);
}
EXPORT_SYMBOL_GPL(tpm_put_ops);
/**
* tpm_chip_find_get() - return tpm_chip for a given chip number
* @chip_num: id to find
*
* The return'd chip has been tpm_try_get_ops'd and must be released via
* tpm_put_ops
*/
struct tpm_chip *tpm_chip_find_get(int chip_num)
{
struct tpm_chip *chip, *res = NULL;
int chip_prev;
mutex_lock(&idr_lock);
if (chip_num == TPM_ANY_NUM) {
chip_num = 0;
do {
chip_prev = chip_num;
chip = idr_get_next(&dev_nums_idr, &chip_num);
if (chip && !tpm_try_get_ops(chip)) {
res = chip;
break;
}
} while (chip_prev != chip_num);
} else {
chip = idr_find(&dev_nums_idr, chip_num);
if (chip && !tpm_try_get_ops(chip))
res = chip;
}
mutex_unlock(&idr_lock);
return res;
}
/**
* tpm_dev_release() - free chip memory and the device number
* @dev: the character device for the TPM chip
*
* This is used as the release function for the character device.
*/
static void tpm_dev_release(struct device *dev)
{
struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
mutex_lock(&idr_lock);
idr_remove(&dev_nums_idr, chip->dev_num);
mutex_unlock(&idr_lock);
kfree(chip->log.bios_event_log);
kfree(chip->work_space.context_buf);
kfree(chip->work_space.session_buf);
kfree(chip);
}
static void tpm_devs_release(struct device *dev)
{
struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs);
/* release the master device reference */
put_device(&chip->dev);
}
/**
* 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);
}
return 0;
}
/**
* tpm_chip_alloc() - allocate a new struct tpm_chip instance
* @pdev: device to which the chip is associated
* At this point pdev mst be initialized, but does not have to
* be registered
* @ops: struct tpm_class_ops instance
*
* Allocates a new struct tpm_chip instance and assigns a free
* device number for it. Must be paired with put_device(&chip->dev).
*/
struct tpm_chip *tpm_chip_alloc(struct device *pdev,
const struct tpm_class_ops *ops)
{
struct tpm_chip *chip;
int rc;
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
if (chip == NULL)
return ERR_PTR(-ENOMEM);
mutex_init(&chip->tpm_mutex);
init_rwsem(&chip->ops_sem);
chip->ops = ops;
mutex_lock(&idr_lock);
rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
mutex_unlock(&idr_lock);
if (rc < 0) {
dev_err(pdev, "No available tpm device numbers\n");
kfree(chip);
return ERR_PTR(rc);
}
chip->dev_num = rc;
device_initialize(&chip->dev);
device_initialize(&chip->devs);
chip->dev.class = tpm_class;
chip->dev.class->shutdown_pre = tpm_class_shutdown;
chip->dev.release = tpm_dev_release;
chip->dev.parent = pdev;
chip->dev.groups = chip->groups;
chip->devs.parent = pdev;
chip->devs.class = tpmrm_class;
chip->devs.release = tpm_devs_release;
/* get extra reference on main device to hold on
* behalf of devs. This holds the chip structure
* while cdevs is in use. The corresponding put
* is in the tpm_devs_release (TPM2 only)
*/
if (chip->flags & TPM_CHIP_FLAG_TPM2)
get_device(&chip->dev);
if (chip->dev_num == 0)
chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
else
chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
chip->devs.devt =
MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES);
rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
if (rc)
goto out;
rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num);
if (rc)
goto out;
if (!pdev)
chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
cdev_init(&chip->cdev, &tpm_fops);
cdev_init(&chip->cdevs, &tpmrm_fops);
chip->cdev.owner = THIS_MODULE;
chip->cdevs.owner = THIS_MODULE;
chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!chip->work_space.context_buf) {
rc = -ENOMEM;
goto out;
}
chip->work_space.session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!chip->work_space.session_buf) {
rc = -ENOMEM;
goto out;
}
chip->locality = -1;
return chip;
out:
put_device(&chip->devs);
put_device(&chip->dev);
return ERR_PTR(rc);
}
EXPORT_SYMBOL_GPL(tpm_chip_alloc);
/**
* tpmm_chip_alloc() - allocate a new struct tpm_chip instance
* @pdev: parent device to which the chip is associated
* @ops: struct tpm_class_ops instance
*
* Same as tpm_chip_alloc except devm is used to do the put_device
*/
struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
const struct tpm_class_ops *ops)
{
struct tpm_chip *chip;
int rc;
chip = tpm_chip_alloc(pdev, ops);
if (IS_ERR(chip))
return chip;
rc = devm_add_action_or_reset(pdev,
(void (*)(void *)) put_device,
&chip->dev);
if (rc)
return ERR_PTR(rc);
dev_set_drvdata(pdev, chip);
return chip;
}
EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
static int tpm_add_char_device(struct tpm_chip *chip)
{
int rc;
rc = cdev_device_add(&chip->cdev, &chip->dev);
if (rc) {
dev_err(&chip->dev,
"unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
dev_name(&chip->dev), MAJOR(chip->dev.devt),
MINOR(chip->dev.devt), rc);
return rc;
}
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
rc = cdev_device_add(&chip->cdevs, &chip->devs);
if (rc) {
dev_err(&chip->devs,
"unable to cdev_device_add() %s, major %d, minor %d, err=%d\n",
dev_name(&chip->devs), MAJOR(chip->devs.devt),
MINOR(chip->devs.devt), rc);
return rc;
}
}
/* Make the chip available. */
mutex_lock(&idr_lock);
idr_replace(&dev_nums_idr, chip, chip->dev_num);
mutex_unlock(&idr_lock);
return rc;
}
static void tpm_del_char_device(struct tpm_chip *chip)
{
cdev_device_del(&chip->cdev, &chip->dev);
/* Make the chip unavailable. */
mutex_lock(&idr_lock);
idr_replace(&dev_nums_idr, NULL, chip->dev_num);
mutex_unlock(&idr_lock);
/* Make the driver uncallable. */
down_write(&chip->ops_sem);
if (chip->flags & TPM_CHIP_FLAG_TPM2)
tpm2_shutdown(chip, TPM2_SU_CLEAR);
chip->ops = NULL;
up_write(&chip->ops_sem);
}
static void tpm_del_legacy_sysfs(struct tpm_chip *chip)
{
struct attribute **i;
if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
return;
sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
for (i = chip->groups[0]->attrs; *i != NULL; ++i)
sysfs_remove_link(&chip->dev.parent->kobj, (*i)->name);
}
/* For compatibility with legacy sysfs paths we provide symlinks from the
* parent dev directory to selected names within the tpm chip directory. Old
* kernel versions created these files directly under the parent.
*/
static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
{
struct attribute **i;
int rc;
if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL))
return 0;
rc = __compat_only_sysfs_link_entry_to_kobj(
&chip->dev.parent->kobj, &chip->dev.kobj, "ppi");
if (rc && rc != -ENOENT)
return rc;
/* All the names from tpm-sysfs */
for (i = chip->groups[0]->attrs; *i != NULL; ++i) {
rc = __compat_only_sysfs_link_entry_to_kobj(
&chip->dev.parent->kobj, &chip->dev.kobj, (*i)->name);
if (rc) {
tpm_del_legacy_sysfs(chip);
return rc;
}
}
return 0;
}
/*
* tpm_chip_register() - create a character device for the TPM chip
* @chip: TPM chip to use.
*
* Creates a character device for the TPM chip and adds sysfs attributes for
* the device. As the last step this function adds the chip to the list of TPM
* chips available for in-kernel use.
*
* This function should be only called after the chip initialization is
* complete.
*/
int tpm_chip_register(struct tpm_chip *chip)
{
int rc;
if (chip->ops->flags & TPM_OPS_AUTO_STARTUP) {
if (chip->flags & TPM_CHIP_FLAG_TPM2)
rc = tpm2_auto_startup(chip);
else
rc = tpm1_auto_startup(chip);
if (rc)
return rc;
}
tpm_sysfs_add_device(chip);
rc = tpm_bios_log_setup(chip);
if (rc != 0 && rc != -ENODEV)
return rc;
tpm_add_ppi(chip);
rc = tpm_add_char_device(chip);
if (rc) {
tpm_bios_log_teardown(chip);
return rc;
}
rc = tpm_add_legacy_sysfs(chip);
if (rc) {
tpm_chip_unregister(chip);
return rc;
}
return 0;
}
EXPORT_SYMBOL_GPL(tpm_chip_register);
/*
* tpm_chip_unregister() - release the TPM driver
* @chip: TPM chip to use.
*
* Takes the chip first away from the list of available TPM chips and then
* cleans up all the resources reserved by tpm_chip_register().
*
* Once this function returns the driver call backs in 'op's will not be
* running and will no longer start.
*
* NOTE: This function should be only called before deinitializing chip
* resources.
*/
void tpm_chip_unregister(struct tpm_chip *chip)
{
tpm_del_legacy_sysfs(chip);
tpm_bios_log_teardown(chip);
if (chip->flags & TPM_CHIP_FLAG_TPM2)
cdev_device_del(&chip->cdevs, &chip->devs);
tpm_del_char_device(chip);
}
EXPORT_SYMBOL_GPL(tpm_chip_unregister);