1 /* 2 * Copyright (C) 2004 IBM Corporation 3 * Copyright (C) 2014 Intel Corporation 4 * 5 * Authors: 6 * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> 7 * Leendert van Doorn <leendert@watson.ibm.com> 8 * Dave Safford <safford@watson.ibm.com> 9 * Reiner Sailer <sailer@watson.ibm.com> 10 * Kylene Hall <kjhall@us.ibm.com> 11 * 12 * Maintained by: <tpmdd-devel@lists.sourceforge.net> 13 * 14 * TPM chip management routines. 15 * 16 * This program is free software; you can redistribute it and/or 17 * modify it under the terms of the GNU General Public License as 18 * published by the Free Software Foundation, version 2 of the 19 * License. 20 * 21 */ 22 23 #include <linux/poll.h> 24 #include <linux/slab.h> 25 #include <linux/mutex.h> 26 #include <linux/spinlock.h> 27 #include <linux/freezer.h> 28 #include <linux/major.h> 29 #include "tpm.h" 30 #include "tpm_eventlog.h" 31 32 DEFINE_IDR(dev_nums_idr); 33 static DEFINE_MUTEX(idr_lock); 34 35 struct class *tpm_class; 36 struct class *tpmrm_class; 37 dev_t tpm_devt; 38 39 /** 40 * tpm_try_get_ops() - Get a ref to the tpm_chip 41 * @chip: Chip to ref 42 * 43 * The caller must already have some kind of locking to ensure that chip is 44 * valid. This function will lock the chip so that the ops member can be 45 * accessed safely. The locking prevents tpm_chip_unregister from 46 * completing, so it should not be held for long periods. 47 * 48 * Returns -ERRNO if the chip could not be got. 49 */ 50 int tpm_try_get_ops(struct tpm_chip *chip) 51 { 52 int rc = -EIO; 53 54 get_device(&chip->dev); 55 56 down_read(&chip->ops_sem); 57 if (!chip->ops) 58 goto out_lock; 59 60 return 0; 61 out_lock: 62 up_read(&chip->ops_sem); 63 put_device(&chip->dev); 64 return rc; 65 } 66 EXPORT_SYMBOL_GPL(tpm_try_get_ops); 67 68 /** 69 * tpm_put_ops() - Release a ref to the tpm_chip 70 * @chip: Chip to put 71 * 72 * This is the opposite pair to tpm_try_get_ops(). After this returns chip may 73 * be kfree'd. 74 */ 75 void tpm_put_ops(struct tpm_chip *chip) 76 { 77 up_read(&chip->ops_sem); 78 put_device(&chip->dev); 79 } 80 EXPORT_SYMBOL_GPL(tpm_put_ops); 81 82 /** 83 * tpm_chip_find_get() - return tpm_chip for a given chip number 84 * @chip_num: id to find 85 * 86 * The return'd chip has been tpm_try_get_ops'd and must be released via 87 * tpm_put_ops 88 */ 89 struct tpm_chip *tpm_chip_find_get(int chip_num) 90 { 91 struct tpm_chip *chip, *res = NULL; 92 int chip_prev; 93 94 mutex_lock(&idr_lock); 95 96 if (chip_num == TPM_ANY_NUM) { 97 chip_num = 0; 98 do { 99 chip_prev = chip_num; 100 chip = idr_get_next(&dev_nums_idr, &chip_num); 101 if (chip && !tpm_try_get_ops(chip)) { 102 res = chip; 103 break; 104 } 105 } while (chip_prev != chip_num); 106 } else { 107 chip = idr_find(&dev_nums_idr, chip_num); 108 if (chip && !tpm_try_get_ops(chip)) 109 res = chip; 110 } 111 112 mutex_unlock(&idr_lock); 113 114 return res; 115 } 116 117 /** 118 * tpm_dev_release() - free chip memory and the device number 119 * @dev: the character device for the TPM chip 120 * 121 * This is used as the release function for the character device. 122 */ 123 static void tpm_dev_release(struct device *dev) 124 { 125 struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev); 126 127 mutex_lock(&idr_lock); 128 idr_remove(&dev_nums_idr, chip->dev_num); 129 mutex_unlock(&idr_lock); 130 131 kfree(chip->log.bios_event_log); 132 kfree(chip->work_space.context_buf); 133 kfree(chip->work_space.session_buf); 134 kfree(chip); 135 } 136 137 static void tpm_devs_release(struct device *dev) 138 { 139 struct tpm_chip *chip = container_of(dev, struct tpm_chip, devs); 140 141 /* release the master device reference */ 142 put_device(&chip->dev); 143 } 144 145 /** 146 * tpm_chip_alloc() - allocate a new struct tpm_chip instance 147 * @pdev: device to which the chip is associated 148 * At this point pdev mst be initialized, but does not have to 149 * be registered 150 * @ops: struct tpm_class_ops instance 151 * 152 * Allocates a new struct tpm_chip instance and assigns a free 153 * device number for it. Must be paired with put_device(&chip->dev). 154 */ 155 struct tpm_chip *tpm_chip_alloc(struct device *pdev, 156 const struct tpm_class_ops *ops) 157 { 158 struct tpm_chip *chip; 159 int rc; 160 161 chip = kzalloc(sizeof(*chip), GFP_KERNEL); 162 if (chip == NULL) 163 return ERR_PTR(-ENOMEM); 164 165 mutex_init(&chip->tpm_mutex); 166 init_rwsem(&chip->ops_sem); 167 168 chip->ops = ops; 169 170 mutex_lock(&idr_lock); 171 rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL); 172 mutex_unlock(&idr_lock); 173 if (rc < 0) { 174 dev_err(pdev, "No available tpm device numbers\n"); 175 kfree(chip); 176 return ERR_PTR(rc); 177 } 178 chip->dev_num = rc; 179 180 device_initialize(&chip->dev); 181 device_initialize(&chip->devs); 182 183 chip->dev.class = tpm_class; 184 chip->dev.release = tpm_dev_release; 185 chip->dev.parent = pdev; 186 chip->dev.groups = chip->groups; 187 188 chip->devs.parent = pdev; 189 chip->devs.class = tpmrm_class; 190 chip->devs.release = tpm_devs_release; 191 /* get extra reference on main device to hold on 192 * behalf of devs. This holds the chip structure 193 * while cdevs is in use. The corresponding put 194 * is in the tpm_devs_release (TPM2 only) 195 */ 196 if (chip->flags & TPM_CHIP_FLAG_TPM2) 197 get_device(&chip->dev); 198 199 if (chip->dev_num == 0) 200 chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR); 201 else 202 chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num); 203 204 chip->devs.devt = 205 MKDEV(MAJOR(tpm_devt), chip->dev_num + TPM_NUM_DEVICES); 206 207 rc = dev_set_name(&chip->dev, "tpm%d", chip->dev_num); 208 if (rc) 209 goto out; 210 rc = dev_set_name(&chip->devs, "tpmrm%d", chip->dev_num); 211 if (rc) 212 goto out; 213 214 if (!pdev) 215 chip->flags |= TPM_CHIP_FLAG_VIRTUAL; 216 217 cdev_init(&chip->cdev, &tpm_fops); 218 cdev_init(&chip->cdevs, &tpmrm_fops); 219 chip->cdev.owner = THIS_MODULE; 220 chip->cdevs.owner = THIS_MODULE; 221 222 chip->work_space.context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL); 223 if (!chip->work_space.context_buf) { 224 rc = -ENOMEM; 225 goto out; 226 } 227 chip->work_space.session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL); 228 if (!chip->work_space.session_buf) { 229 rc = -ENOMEM; 230 goto out; 231 } 232 233 chip->locality = -1; 234 return chip; 235 236 out: 237 put_device(&chip->devs); 238 put_device(&chip->dev); 239 return ERR_PTR(rc); 240 } 241 EXPORT_SYMBOL_GPL(tpm_chip_alloc); 242 243 /** 244 * tpmm_chip_alloc() - allocate a new struct tpm_chip instance 245 * @pdev: parent device to which the chip is associated 246 * @ops: struct tpm_class_ops instance 247 * 248 * Same as tpm_chip_alloc except devm is used to do the put_device 249 */ 250 struct tpm_chip *tpmm_chip_alloc(struct device *pdev, 251 const struct tpm_class_ops *ops) 252 { 253 struct tpm_chip *chip; 254 int rc; 255 256 chip = tpm_chip_alloc(pdev, ops); 257 if (IS_ERR(chip)) 258 return chip; 259 260 rc = devm_add_action_or_reset(pdev, 261 (void (*)(void *)) put_device, 262 &chip->dev); 263 if (rc) 264 return ERR_PTR(rc); 265 266 dev_set_drvdata(pdev, chip); 267 268 return chip; 269 } 270 EXPORT_SYMBOL_GPL(tpmm_chip_alloc); 271 272 static int tpm_add_char_device(struct tpm_chip *chip) 273 { 274 int rc; 275 276 rc = cdev_device_add(&chip->cdev, &chip->dev); 277 if (rc) { 278 dev_err(&chip->dev, 279 "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n", 280 dev_name(&chip->dev), MAJOR(chip->dev.devt), 281 MINOR(chip->dev.devt), rc); 282 return rc; 283 } 284 285 if (chip->flags & TPM_CHIP_FLAG_TPM2) { 286 rc = cdev_device_add(&chip->cdevs, &chip->devs); 287 if (rc) { 288 dev_err(&chip->devs, 289 "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n", 290 dev_name(&chip->devs), MAJOR(chip->devs.devt), 291 MINOR(chip->devs.devt), rc); 292 return rc; 293 } 294 } 295 296 /* Make the chip available. */ 297 mutex_lock(&idr_lock); 298 idr_replace(&dev_nums_idr, chip, chip->dev_num); 299 mutex_unlock(&idr_lock); 300 301 return rc; 302 } 303 304 static void tpm_del_char_device(struct tpm_chip *chip) 305 { 306 cdev_device_del(&chip->cdev, &chip->dev); 307 308 /* Make the chip unavailable. */ 309 mutex_lock(&idr_lock); 310 idr_replace(&dev_nums_idr, NULL, chip->dev_num); 311 mutex_unlock(&idr_lock); 312 313 /* Make the driver uncallable. */ 314 down_write(&chip->ops_sem); 315 if (chip->flags & TPM_CHIP_FLAG_TPM2) 316 tpm2_shutdown(chip, TPM2_SU_CLEAR); 317 chip->ops = NULL; 318 up_write(&chip->ops_sem); 319 } 320 321 static void tpm_del_legacy_sysfs(struct tpm_chip *chip) 322 { 323 struct attribute **i; 324 325 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL)) 326 return; 327 328 sysfs_remove_link(&chip->dev.parent->kobj, "ppi"); 329 330 for (i = chip->groups[0]->attrs; *i != NULL; ++i) 331 sysfs_remove_link(&chip->dev.parent->kobj, (*i)->name); 332 } 333 334 /* For compatibility with legacy sysfs paths we provide symlinks from the 335 * parent dev directory to selected names within the tpm chip directory. Old 336 * kernel versions created these files directly under the parent. 337 */ 338 static int tpm_add_legacy_sysfs(struct tpm_chip *chip) 339 { 340 struct attribute **i; 341 int rc; 342 343 if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL)) 344 return 0; 345 346 rc = __compat_only_sysfs_link_entry_to_kobj( 347 &chip->dev.parent->kobj, &chip->dev.kobj, "ppi"); 348 if (rc && rc != -ENOENT) 349 return rc; 350 351 /* All the names from tpm-sysfs */ 352 for (i = chip->groups[0]->attrs; *i != NULL; ++i) { 353 rc = __compat_only_sysfs_link_entry_to_kobj( 354 &chip->dev.parent->kobj, &chip->dev.kobj, (*i)->name); 355 if (rc) { 356 tpm_del_legacy_sysfs(chip); 357 return rc; 358 } 359 } 360 361 return 0; 362 } 363 /* 364 * tpm_chip_register() - create a character device for the TPM chip 365 * @chip: TPM chip to use. 366 * 367 * Creates a character device for the TPM chip and adds sysfs attributes for 368 * the device. As the last step this function adds the chip to the list of TPM 369 * chips available for in-kernel use. 370 * 371 * This function should be only called after the chip initialization is 372 * complete. 373 */ 374 int tpm_chip_register(struct tpm_chip *chip) 375 { 376 int rc; 377 378 if (chip->ops->flags & TPM_OPS_AUTO_STARTUP) { 379 if (chip->flags & TPM_CHIP_FLAG_TPM2) 380 rc = tpm2_auto_startup(chip); 381 else 382 rc = tpm1_auto_startup(chip); 383 if (rc) 384 return rc; 385 } 386 387 tpm_sysfs_add_device(chip); 388 389 rc = tpm_bios_log_setup(chip); 390 if (rc != 0 && rc != -ENODEV) 391 return rc; 392 393 tpm_add_ppi(chip); 394 395 rc = tpm_add_char_device(chip); 396 if (rc) { 397 tpm_bios_log_teardown(chip); 398 return rc; 399 } 400 401 rc = tpm_add_legacy_sysfs(chip); 402 if (rc) { 403 tpm_chip_unregister(chip); 404 return rc; 405 } 406 407 return 0; 408 } 409 EXPORT_SYMBOL_GPL(tpm_chip_register); 410 411 /* 412 * tpm_chip_unregister() - release the TPM driver 413 * @chip: TPM chip to use. 414 * 415 * Takes the chip first away from the list of available TPM chips and then 416 * cleans up all the resources reserved by tpm_chip_register(). 417 * 418 * Once this function returns the driver call backs in 'op's will not be 419 * running and will no longer start. 420 * 421 * NOTE: This function should be only called before deinitializing chip 422 * resources. 423 */ 424 void tpm_chip_unregister(struct tpm_chip *chip) 425 { 426 tpm_del_legacy_sysfs(chip); 427 tpm_bios_log_teardown(chip); 428 if (chip->flags & TPM_CHIP_FLAG_TPM2) 429 cdev_device_del(&chip->cdevs, &chip->devs); 430 tpm_del_char_device(chip); 431 } 432 EXPORT_SYMBOL_GPL(tpm_chip_unregister); 433