/* * Copyright (C) 2004 IBM Corporation * Copyright (C) 2014 Intel Corporation * * Authors: * Jarkko Sakkinen * Leendert van Doorn * Dave Safford * Reiner Sailer * Kylene Hall * * Maintained by: * * 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 #include #include #include #include #include #include #include #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; static int tpm_request_locality(struct tpm_chip *chip) { int rc; if (!chip->ops->request_locality) return 0; rc = chip->ops->request_locality(chip, 0); if (rc < 0) return rc; chip->locality = rc; return 0; } static void tpm_relinquish_locality(struct tpm_chip *chip) { int rc; if (!chip->ops->relinquish_locality) return; rc = chip->ops->relinquish_locality(chip, chip->locality); if (rc) dev_err(&chip->dev, "%s: : error %d\n", __func__, rc); chip->locality = -1; } static int tpm_cmd_ready(struct tpm_chip *chip) { if (!chip->ops->cmd_ready) return 0; return chip->ops->cmd_ready(chip); } static int tpm_go_idle(struct tpm_chip *chip) { if (!chip->ops->go_idle) return 0; return chip->ops->go_idle(chip); } /** * tpm_chip_start() - power on the TPM * @chip: a TPM chip to use * * Return: * * The response length - OK * * -errno - A system error */ int tpm_chip_start(struct tpm_chip *chip) { int ret; if (chip->ops->clk_enable) chip->ops->clk_enable(chip, true); if (chip->locality == -1) { ret = tpm_request_locality(chip); if (ret) { chip->ops->clk_enable(chip, false); return ret; } } ret = tpm_cmd_ready(chip); if (ret) { tpm_relinquish_locality(chip); if (chip->ops->clk_enable) chip->ops->clk_enable(chip, false); return ret; } return 0; } EXPORT_SYMBOL_GPL(tpm_chip_start); /** * tpm_chip_stop() - power off the TPM * @chip: a TPM chip to use * * Return: * * The response length - OK * * -errno - A system error */ void tpm_chip_stop(struct tpm_chip *chip) { tpm_go_idle(chip); tpm_relinquish_locality(chip); if (chip->ops->clk_enable) chip->ops->clk_enable(chip, false); } EXPORT_SYMBOL_GPL(tpm_chip_stop); /** * 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_ops; mutex_lock(&chip->tpm_mutex); rc = tpm_chip_start(chip); if (rc) goto out_lock; return 0; out_lock: mutex_unlock(&chip->tpm_mutex); out_ops: 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) { tpm_chip_stop(chip); mutex_unlock(&chip->tpm_mutex); 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->allocated_banks); 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); if (!tpm_chip_start(chip)) { tpm2_shutdown(chip, TPM2_SU_CLEAR); tpm_chip_stop(chip); } 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) { if (!tpm_chip_start(chip)) { tpm2_shutdown(chip, TPM2_SU_CLEAR); tpm_chip_stop(chip); } } 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; rc = tpm_chip_start(chip); if (rc) return rc; rc = tpm_auto_startup(chip); tpm_chip_stop(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);