drivers/crypto/ccp/ccp-dev.c

   1 /*
   2  * AMD Cryptographic Coprocessor (CCP) driver
   3  *
   4  * Copyright (C) 2013 Advanced Micro Devices, Inc.
   5  *
   6  * Author: Tom Lendacky <thomas.lendacky@amd.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/kthread.h>
  16 #include <linux/sched.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/mutex.h>
  20 #include <linux/delay.h>
  21 #include <linux/hw_random.h>
  22 #include <linux/cpu.h>
  23 #include <asm/cpu_device_id.h>
  24 #include <linux/ccp.h>
  25
  26 #include "ccp-dev.h"
  27
  28 MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
  29 MODULE_LICENSE("GPL");
  30 MODULE_VERSION("1.0.0");
  31 MODULE_DESCRIPTION("AMD Cryptographic Coprocessor driver");
  32
  33 struct ccp_tasklet_data {
  34         struct completion completion;
  35         struct ccp_cmd *cmd;
  36 };
  37
  38
  39 static struct ccp_device *ccp_dev;
  40 static inline struct ccp_device *ccp_get_device(void)
  41 {
  42         return ccp_dev;
  43 }
  44
  45 static inline void ccp_add_device(struct ccp_device *ccp)
  46 {
  47         ccp_dev = ccp;
  48 }
  49
  50 static inline void ccp_del_device(struct ccp_device *ccp)
  51 {
  52         ccp_dev = NULL;
  53 }
  54
  55 /**
  56  * ccp_enqueue_cmd - queue an operation for processing by the CCP
  57  *
  58  * @cmd: ccp_cmd struct to be processed
  59  *
  60  * Queue a cmd to be processed by the CCP. If queueing the cmd
  61  * would exceed the defined length of the cmd queue the cmd will
  62  * only be queued if the CCP_CMD_MAY_BACKLOG flag is set and will
  63  * result in a return code of -EBUSY.
  64  *
  65  * The callback routine specified in the ccp_cmd struct will be
  66  * called to notify the caller of completion (if the cmd was not
  67  * backlogged) or advancement out of the backlog. If the cmd has
  68  * advanced out of the backlog the "err" value of the callback
  69  * will be -EINPROGRESS. Any other "err" value during callback is
  70  * the result of the operation.
  71  *
  72  * The cmd has been successfully queued if:
  73  *   the return code is -EINPROGRESS or
  74  *   the return code is -EBUSY and CCP_CMD_MAY_BACKLOG flag is set
  75  */
  76 int ccp_enqueue_cmd(struct ccp_cmd *cmd)
  77 {
  78         struct ccp_device *ccp = ccp_get_device();
  79         unsigned long flags;
  80         unsigned int i;
  81         int ret;
  82
  83         if (!ccp)
  84                 return -ENODEV;
  85
  86         /* Caller must supply a callback routine */
  87         if (!cmd->callback)
  88                 return -EINVAL;
  89
  90         cmd->ccp = ccp;
  91
  92         spin_lock_irqsave(&ccp->cmd_lock, flags);
  93
  94         i = ccp->cmd_q_count;
  95
  96         if (ccp->cmd_count >= MAX_CMD_QLEN) {
  97                 ret = -EBUSY;
  98                 if (cmd->flags & CCP_CMD_MAY_BACKLOG)
  99                         list_add_tail(&cmd->entry, &ccp->backlog);
 100         } else {
 101                 ret = -EINPROGRESS;
 102                 ccp->cmd_count++;
 103                 list_add_tail(&cmd->entry, &ccp->cmd);
 104
 105                 /* Find an idle queue */
 106                 if (!ccp->suspending) {
 107                         for (i = 0; i < ccp->cmd_q_count; i++) {
 108                                 if (ccp->cmd_q[i].active)
 109                                         continue;
 110
 111                                 break;
 112                         }
 113                 }
 114         }
 115
 116         spin_unlock_irqrestore(&ccp->cmd_lock, flags);
 117
 118         /* If we found an idle queue, wake it up */
 119         if (i < ccp->cmd_q_count)
 120                 wake_up_process(ccp->cmd_q[i].kthread);
 121
 122         return ret;
 123 }
 124 EXPORT_SYMBOL_GPL(ccp_enqueue_cmd);
 125
 126 static void ccp_do_cmd_backlog(struct work_struct *work)
 127 {
 128         struct ccp_cmd *cmd = container_of(work, struct ccp_cmd, work);
 129         struct ccp_device *ccp = cmd->ccp;
 130         unsigned long flags;
 131         unsigned int i;
 132
 133         cmd->callback(cmd->data, -EINPROGRESS);
 134
 135         spin_lock_irqsave(&ccp->cmd_lock, flags);
 136
 137         ccp->cmd_count++;
 138         list_add_tail(&cmd->entry, &ccp->cmd);
 139
 140         /* Find an idle queue */
 141         for (i = 0; i < ccp->cmd_q_count; i++) {
 142                 if (ccp->cmd_q[i].active)
 143                         continue;
 144
 145                 break;
 146         }
 147
 148         spin_unlock_irqrestore(&ccp->cmd_lock, flags);
 149
 150         /* If we found an idle queue, wake it up */
 151         if (i < ccp->cmd_q_count)
 152                 wake_up_process(ccp->cmd_q[i].kthread);
 153 }
 154
 155 static struct ccp_cmd *ccp_dequeue_cmd(struct ccp_cmd_queue *cmd_q)
 156 {
 157         struct ccp_device *ccp = cmd_q->ccp;
 158         struct ccp_cmd *cmd = NULL;
 159         struct ccp_cmd *backlog = NULL;
 160         unsigned long flags;
 161
 162         spin_lock_irqsave(&ccp->cmd_lock, flags);
 163
 164         cmd_q->active = 0;
 165
 166         if (ccp->suspending) {
 167                 cmd_q->suspended = 1;
 168
 169                 spin_unlock_irqrestore(&ccp->cmd_lock, flags);
 170                 wake_up_interruptible(&ccp->suspend_queue);
 171
 172                 return NULL;
 173         }
 174
 175         if (ccp->cmd_count) {
 176                 cmd_q->active = 1;
 177
 178                 cmd = list_first_entry(&ccp->cmd, struct ccp_cmd, entry);
 179                 list_del(&cmd->entry);
 180
 181                 ccp->cmd_count--;
 182         }
 183
 184         if (!list_empty(&ccp->backlog)) {
 185                 backlog = list_first_entry(&ccp->backlog, struct ccp_cmd,
 186                                            entry);
 187                 list_del(&backlog->entry);
 188         }
 189
 190         spin_unlock_irqrestore(&ccp->cmd_lock, flags);
 191
 192         if (backlog) {
 193                 INIT_WORK(&backlog->work, ccp_do_cmd_backlog);
 194                 schedule_work(&backlog->work);
 195         }
 196
 197         return cmd;
 198 }
 199
 200 static void ccp_do_cmd_complete(unsigned long data)
 201 {
 202         struct ccp_tasklet_data *tdata = (struct ccp_tasklet_data *)data;
 203         struct ccp_cmd *cmd = tdata->cmd;
 204
 205         cmd->callback(cmd->data, cmd->ret);
 206         complete(&tdata->completion);
 207 }
 208
 209 static int ccp_cmd_queue_thread(void *data)
 210 {
 211         struct ccp_cmd_queue *cmd_q = (struct ccp_cmd_queue *)data;
 212         struct ccp_cmd *cmd;
 213         struct ccp_tasklet_data tdata;
 214         struct tasklet_struct tasklet;
 215
 216         tasklet_init(&tasklet, ccp_do_cmd_complete, (unsigned long)&tdata);
 217
 218         set_current_state(TASK_INTERRUPTIBLE);
 219         while (!kthread_should_stop()) {
 220                 schedule();
 221
 222                 set_current_state(TASK_INTERRUPTIBLE);
 223
 224                 cmd = ccp_dequeue_cmd(cmd_q);
 225                 if (!cmd)
 226                         continue;
 227
 228                 __set_current_state(TASK_RUNNING);
 229
 230                 /* Execute the command */
 231                 cmd->ret = ccp_run_cmd(cmd_q, cmd);
 232
 233                 /* Schedule the completion callback */
 234                 tdata.cmd = cmd;
 235                 init_completion(&tdata.completion);
 236                 tasklet_schedule(&tasklet);
 237                 wait_for_completion(&tdata.completion);
 238         }
 239
 240         __set_current_state(TASK_RUNNING);
 241
 242         return 0;
 243 }
 244
 245 static int ccp_trng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 246 {
 247         struct ccp_device *ccp = container_of(rng, struct ccp_device, hwrng);
 248         u32 trng_value;
 249         int len = min_t(int, sizeof(trng_value), max);
 250
 251         /*
 252          * Locking is provided by the caller so we can update device
 253          * hwrng-related fields safely
 254          */
 255         trng_value = ioread32(ccp->io_regs + TRNG_OUT_REG);
 256         if (!trng_value) {
 257                 /* Zero is returned if not data is available or if a
 258                  * bad-entropy error is present. Assume an error if
 259                  * we exceed TRNG_RETRIES reads of zero.
 260                  */
 261                 if (ccp->hwrng_retries++ > TRNG_RETRIES)
 262                         return -EIO;
 263
 264                 return 0;
 265         }
 266
 267         /* Reset the counter and save the rng value */
 268         ccp->hwrng_retries = 0;
 269         memcpy(data, &trng_value, len);
 270
 271         return len;
 272 }
 273
 274 /**
 275  * ccp_alloc_struct - allocate and initialize the ccp_device struct
 276  *
 277  * @dev: device struct of the CCP
 278  */
 279 struct ccp_device *ccp_alloc_struct(struct device *dev)
 280 {
 281         struct ccp_device *ccp;
 282
 283         ccp = kzalloc(sizeof(*ccp), GFP_KERNEL);
 284         if (ccp == NULL) {
 285                 dev_err(dev, "unable to allocate device struct\n");
 286                 return NULL;
 287         }
 288         ccp->dev = dev;
 289
 290         INIT_LIST_HEAD(&ccp->cmd);
 291         INIT_LIST_HEAD(&ccp->backlog);
 292
 293         spin_lock_init(&ccp->cmd_lock);
 294         mutex_init(&ccp->req_mutex);
 295         mutex_init(&ccp->ksb_mutex);
 296         ccp->ksb_count = KSB_COUNT;
 297         ccp->ksb_start = 0;
 298
 299         return ccp;
 300 }
 301
 302 /**
 303  * ccp_init - initialize the CCP device
 304  *
 305  * @ccp: ccp_device struct
 306  */
 307 int ccp_init(struct ccp_device *ccp)
 308 {
 309         struct device *dev = ccp->dev;
 310         struct ccp_cmd_queue *cmd_q;
 311         struct dma_pool *dma_pool;
 312         char dma_pool_name[MAX_DMAPOOL_NAME_LEN];
 313         unsigned int qmr, qim, i;
 314         int ret;
 315
 316         /* Find available queues */
 317         qim = 0;
 318         qmr = ioread32(ccp->io_regs + Q_MASK_REG);
 319         for (i = 0; i < MAX_HW_QUEUES; i++) {
 320                 if (!(qmr & (1 << i)))
 321                         continue;
 322
 323                 /* Allocate a dma pool for this queue */
 324                 snprintf(dma_pool_name, sizeof(dma_pool_name), "ccp_q%d", i);
 325                 dma_pool = dma_pool_create(dma_pool_name, dev,
 326                                            CCP_DMAPOOL_MAX_SIZE,
 327                                            CCP_DMAPOOL_ALIGN, 0);
 328                 if (!dma_pool) {
 329                         dev_err(dev, "unable to allocate dma pool\n");
 330                         ret = -ENOMEM;
 331                         goto e_pool;
 332                 }
 333
 334                 cmd_q = &ccp->cmd_q[ccp->cmd_q_count];
 335                 ccp->cmd_q_count++;
 336
 337                 cmd_q->ccp = ccp;
 338                 cmd_q->id = i;
 339                 cmd_q->dma_pool = dma_pool;
 340
 341                 /* Reserve 2 KSB regions for the queue */
 342                 cmd_q->ksb_key = KSB_START + ccp->ksb_start++;
 343                 cmd_q->ksb_ctx = KSB_START + ccp->ksb_start++;
 344                 ccp->ksb_count -= 2;
 345
 346                 /* Preset some register values and masks that are queue
 347                  * number dependent
 348                  */
 349                 cmd_q->reg_status = ccp->io_regs + CMD_Q_STATUS_BASE +
 350                                     (CMD_Q_STATUS_INCR * i);
 351                 cmd_q->reg_int_status = ccp->io_regs + CMD_Q_INT_STATUS_BASE +
 352                                         (CMD_Q_STATUS_INCR * i);
 353                 cmd_q->int_ok = 1 << (i * 2);
 354                 cmd_q->int_err = 1 << ((i * 2) + 1);
 355
 356                 cmd_q->free_slots = CMD_Q_DEPTH(ioread32(cmd_q->reg_status));
 357
 358                 init_waitqueue_head(&cmd_q->int_queue);
 359
 360                 /* Build queue interrupt mask (two interrupts per queue) */
 361                 qim |= cmd_q->int_ok | cmd_q->int_err;
 362
 363                 dev_dbg(dev, "queue #%u available\n", i);
 364         }
 365         if (ccp->cmd_q_count == 0) {
 366                 dev_notice(dev, "no command queues available\n");
 367                 ret = -EIO;
 368                 goto e_pool;
 369         }
 370         dev_notice(dev, "%u command queues available\n", ccp->cmd_q_count);
 371
 372         /* Disable and clear interrupts until ready */
 373         iowrite32(0x00, ccp->io_regs + IRQ_MASK_REG);
 374         for (i = 0; i < ccp->cmd_q_count; i++) {
 375                 cmd_q = &ccp->cmd_q[i];
 376
 377                 ioread32(cmd_q->reg_int_status);
 378                 ioread32(cmd_q->reg_status);
 379         }
 380         iowrite32(qim, ccp->io_regs + IRQ_STATUS_REG);
 381
 382         /* Request an irq */
 383         ret = ccp->get_irq(ccp);
 384         if (ret) {
 385                 dev_err(dev, "unable to allocate an IRQ\n");
 386                 goto e_pool;
 387         }
 388
 389         /* Initialize the queues used to wait for KSB space and suspend */
 390         init_waitqueue_head(&ccp->ksb_queue);
 391         init_waitqueue_head(&ccp->suspend_queue);
 392
 393         /* Create a kthread for each queue */
 394         for (i = 0; i < ccp->cmd_q_count; i++) {
 395                 struct task_struct *kthread;
 396
 397                 cmd_q = &ccp->cmd_q[i];
 398
 399                 kthread = kthread_create(ccp_cmd_queue_thread, cmd_q,
 400                                          "ccp-q%u", cmd_q->id);
 401                 if (IS_ERR(kthread)) {
 402                         dev_err(dev, "error creating queue thread (%ld)\n",
 403                                 PTR_ERR(kthread));
 404                         ret = PTR_ERR(kthread);
 405                         goto e_kthread;
 406                 }
 407
 408                 cmd_q->kthread = kthread;
 409                 wake_up_process(kthread);
 410         }
 411
 412         /* Register the RNG */
 413         ccp->hwrng.name = "ccp-rng";
 414         ccp->hwrng.read = ccp_trng_read;
 415         ret = hwrng_register(&ccp->hwrng);
 416         if (ret) {
 417                 dev_err(dev, "error registering hwrng (%d)\n", ret);
 418                 goto e_kthread;
 419         }
 420
 421         /* Make the device struct available before enabling interrupts */
 422         ccp_add_device(ccp);
 423
 424         /* Enable interrupts */
 425         iowrite32(qim, ccp->io_regs + IRQ_MASK_REG);
 426
 427         return 0;
 428
 429 e_kthread:
 430         for (i = 0; i < ccp->cmd_q_count; i++)
 431                 if (ccp->cmd_q[i].kthread)
 432                         kthread_stop(ccp->cmd_q[i].kthread);
 433
 434         ccp->free_irq(ccp);
 435
 436 e_pool:
 437         for (i = 0; i < ccp->cmd_q_count; i++)
 438                 dma_pool_destroy(ccp->cmd_q[i].dma_pool);
 439
 440         return ret;
 441 }
 442
 443 /**
 444  * ccp_destroy - tear down the CCP device
 445  *
 446  * @ccp: ccp_device struct
 447  */
 448 void ccp_destroy(struct ccp_device *ccp)
 449 {
 450         struct ccp_cmd_queue *cmd_q;
 451         struct ccp_cmd *cmd;
 452         unsigned int qim, i;
 453
 454         /* Remove general access to the device struct */
 455         ccp_del_device(ccp);
 456
 457         /* Unregister the RNG */
 458         hwrng_unregister(&ccp->hwrng);
 459
 460         /* Stop the queue kthreads */
 461         for (i = 0; i < ccp->cmd_q_count; i++)
 462                 if (ccp->cmd_q[i].kthread)
 463                         kthread_stop(ccp->cmd_q[i].kthread);
 464
 465         /* Build queue interrupt mask (two interrupt masks per queue) */
 466         qim = 0;
 467         for (i = 0; i < ccp->cmd_q_count; i++) {
 468                 cmd_q = &ccp->cmd_q[i];
 469                 qim |= cmd_q->int_ok | cmd_q->int_err;
 470         }
 471
 472         /* Disable and clear interrupts */
 473         iowrite32(0x00, ccp->io_regs + IRQ_MASK_REG);
 474         for (i = 0; i < ccp->cmd_q_count; i++) {
 475                 cmd_q = &ccp->cmd_q[i];
 476
 477                 ioread32(cmd_q->reg_int_status);
 478                 ioread32(cmd_q->reg_status);
 479         }
 480         iowrite32(qim, ccp->io_regs + IRQ_STATUS_REG);
 481
 482         ccp->free_irq(ccp);
 483
 484         for (i = 0; i < ccp->cmd_q_count; i++)
 485                 dma_pool_destroy(ccp->cmd_q[i].dma_pool);
 486
 487         /* Flush the cmd and backlog queue */
 488         while (!list_empty(&ccp->cmd)) {
 489                 /* Invoke the callback directly with an error code */
 490                 cmd = list_first_entry(&ccp->cmd, struct ccp_cmd, entry);
 491                 list_del(&cmd->entry);
 492                 cmd->callback(cmd->data, -ENODEV);
 493         }
 494         while (!list_empty(&ccp->backlog)) {
 495                 /* Invoke the callback directly with an error code */
 496                 cmd = list_first_entry(&ccp->backlog, struct ccp_cmd, entry);
 497                 list_del(&cmd->entry);
 498                 cmd->callback(cmd->data, -ENODEV);
 499         }
 500 }
 501
 502 /**
 503  * ccp_irq_handler - handle interrupts generated by the CCP device
 504  *
 505  * @irq: the irq associated with the interrupt
 506  * @data: the data value supplied when the irq was created
 507  */
 508 irqreturn_t ccp_irq_handler(int irq, void *data)
 509 {
 510         struct device *dev = data;
 511         struct ccp_device *ccp = dev_get_drvdata(dev);
 512         struct ccp_cmd_queue *cmd_q;
 513         u32 q_int, status;
 514         unsigned int i;
 515
 516         status = ioread32(ccp->io_regs + IRQ_STATUS_REG);
 517
 518         for (i = 0; i < ccp->cmd_q_count; i++) {
 519                 cmd_q = &ccp->cmd_q[i];
 520
 521                 q_int = status & (cmd_q->int_ok | cmd_q->int_err);
 522                 if (q_int) {
 523                         cmd_q->int_status = status;
 524                         cmd_q->q_status = ioread32(cmd_q->reg_status);
 525                         cmd_q->q_int_status = ioread32(cmd_q->reg_int_status);
 526
 527                         /* On error, only save the first error value */
 528                         if ((q_int & cmd_q->int_err) && !cmd_q->cmd_error)
 529                                 cmd_q->cmd_error = CMD_Q_ERROR(cmd_q->q_status);
 530
 531                         cmd_q->int_rcvd = 1;
 532
 533                         /* Acknowledge the interrupt and wake the kthread */
 534                         iowrite32(q_int, ccp->io_regs + IRQ_STATUS_REG);
 535                         wake_up_interruptible(&cmd_q->int_queue);
 536                 }
 537         }
 538
 539         return IRQ_HANDLED;
 540 }
 541
 542 #ifdef CONFIG_PM
 543 bool ccp_queues_suspended(struct ccp_device *ccp)
 544 {
 545         unsigned int suspended = 0;
 546         unsigned long flags;
 547         unsigned int i;
 548
 549         spin_lock_irqsave(&ccp->cmd_lock, flags);
 550
 551         for (i = 0; i < ccp->cmd_q_count; i++)
 552                 if (ccp->cmd_q[i].suspended)
 553                         suspended++;
 554
 555         spin_unlock_irqrestore(&ccp->cmd_lock, flags);
 556
 557         return ccp->cmd_q_count == suspended;
 558 }
 559 #endif
 560
 561 static const struct x86_cpu_id ccp_support[] = {
 562         { X86_VENDOR_AMD, 22, },
 563 };
 564
 565 static int __init ccp_mod_init(void)
 566 {
 567         struct cpuinfo_x86 *cpuinfo = &boot_cpu_data;
 568         int ret;
 569
 570         if (!x86_match_cpu(ccp_support))
 571                 return -ENODEV;
 572
 573         switch (cpuinfo->x86) {
 574         case 22:
 575                 if ((cpuinfo->x86_model < 48) || (cpuinfo->x86_model > 63))
 576                         return -ENODEV;
 577
 578                 ret = ccp_pci_init();
 579                 if (ret)
 580                         return ret;
 581
 582                 /* Don't leave the driver loaded if init failed */
 583                 if (!ccp_get_device()) {
 584                         ccp_pci_exit();
 585                         return -ENODEV;
 586                 }
 587
 588                 return 0;
 589
 590                 break;
 591         }
 592
 593         return -ENODEV;
 594 }
 595
 596 static void __exit ccp_mod_exit(void)
 597 {
 598         struct cpuinfo_x86 *cpuinfo = &boot_cpu_data;
 599
 600         switch (cpuinfo->x86) {
 601         case 22:
 602                 ccp_pci_exit();
 603                 break;
 604         }
 605 }
 606
 607 module_init(ccp_mod_init);
 608 module_exit(ccp_mod_exit);