/*
* 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 <linux/tpm_eventlog.h>
#include <linux/hw_random.h>
#include "tpm.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_default_chip() - find a TPM chip and get a reference to it
*/
struct tpm_chip *tpm_default_chip(void)
{
struct tpm_chip *chip, *res = NULL;
int chip_num = 0;
int chip_prev;
mutex_lock(&idr_lock);
do {
chip_prev = chip_num;
chip = idr_get_next(&dev_nums_idr, &chip_num);
if (chip) {
get_device(&chip->dev);
res = chip;
break;
}
} while (chip_prev != chip_num);
mutex_unlock(&idr_lock);
return res;
}
EXPORT_SYMBOL_GPL(tpm_default_chip);
/**
* tpm_find_get_ops() - find and reserve a TPM chip
* @chip: a &struct tpm_chip instance, %NULL for the default chip
*
* Finds a TPM chip and reserves its class device and operations. The chip must
* be released with tpm_put_ops() after use.
* This function is for internal use only. It supports existing TPM callers
* by accepting NULL, but those callers should be converted to pass in a chip
* directly.
*
* Return:
* A reserved &struct tpm_chip instance.
* %NULL if a chip is not found.
* %NULL if the chip is not available.
*/
struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip)
{
int rc;
if (chip) {
if (!tpm_try_get_ops(chip))
return chip;
return NULL;
}
chip = tpm_default_chip();
if (!chip)
return NULL;
rc = tpm_try_get_ops(chip);
/* release additional reference we got from tpm_default_chip() */
put_device(&chip->dev);
if (rc)
return NULL;
return chip;
}
/**
* 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;
}
static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
{
struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng);
return tpm_get_random(chip, data, max);
}
static int tpm_add_hwrng(struct tpm_chip *chip)
{
if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM))
return 0;
snprintf(chip->hwrng_name, sizeof(chip->hwrng_name),
"tpm-rng-%d", chip->dev_num);
chip->hwrng.name = chip->hwrng_name;
chip->hwrng.read = tpm_hwrng_read;
return hwrng_register(&chip->hwrng);
}
/*
* 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_hwrng(chip);
if (rc)
goto out_ppi;
rc = tpm_add_char_device(chip);
if (rc)
goto out_hwrng;
rc = tpm_add_legacy_sysfs(chip);
if (rc) {
tpm_chip_unregister(chip);
return rc;
}
return 0;
out_hwrng:
if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
hwrng_unregister(&chip->hwrng);
out_ppi:
tpm_bios_log_teardown(chip);
return rc;
}
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);
if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
hwrng_unregister(&chip->hwrng);
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);
