1 files changed, 484 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
new file mode 100644
index 000000000..2d62a3649
--- /dev/null
+++ b/drivers/char/tpm/tpm-chip.c
@@ -0,0 +1,484 @@
+/*
+ * 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);
+}
+
+/**
+ * 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);
+
+	down_write(&chip->ops_sem);
+	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+		tpm2_shutdown(chip, TPM2_SU_CLEAR);
+		chip->ops = NULL;
+	}
+	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);
+
+	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;
+
+	if (chip->dev_num == 0)
+		chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
+	else
+		chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num);
+
+	rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num);
+	if (rc)
+		goto out;
+
+	if (!pdev)
+		chip->flags |= TPM_CHIP_FLAG_VIRTUAL;
+
+	cdev_init(&chip->cdev, &tpm_fops);
+	chip->cdev.owner = THIS_MODULE;
+
+	rc = tpm2_init_space(&chip->work_space, TPM2_SPACE_BUFFER_SIZE);
+	if (rc) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	chip->locality = -1;
+	return chip;
+
+out:
+	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 = tpm_devs_add(chip);
+		if (rc)
+			goto err_del_cdev;
+	}
+
+	/* Make the chip available. */
+	mutex_lock(&idr_lock);
+	idr_replace(&dev_nums_idr, chip, chip->dev_num);
+	mutex_unlock(&idr_lock);
+
+	return 0;
+
+err_del_cdev:
+	cdev_device_del(&chip->cdev, &chip->dev);
+	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);
+
+	tpm_bios_log_setup(chip);
+
+	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)
+		tpm_devs_remove(chip);
+	tpm_del_char_device(chip);
+}
+EXPORT_SYMBOL_GPL(tpm_chip_unregister);