drivers/misc/ocxl/file.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 // Copyright 2017 IBM Corp.
   3 #include <linux/fs.h>
   4 #include <linux/poll.h>
   5 #include <linux/sched/signal.h>
   6 #include <linux/eventfd.h>
   7 #include <linux/uaccess.h>
   8 #include <uapi/misc/ocxl.h>
   9 #include <asm/reg.h>
  10 #include <asm/switch_to.h>
  11 #include "ocxl_internal.h"
  12
  13
  14 #define OCXL_NUM_MINORS 256 /* Total to reserve */
  15
  16 static dev_t ocxl_dev;
  17 static struct class *ocxl_class;
  18 static struct mutex minors_idr_lock;
  19 static struct idr minors_idr;
  20
  21 static struct ocxl_file_info *find_and_get_file_info(dev_t devno)
  22 {
  23         struct ocxl_file_info *info;
  24
  25         mutex_lock(&minors_idr_lock);
  26         info = idr_find(&minors_idr, MINOR(devno));
  27         if (info)
  28                 get_device(&info->dev);
  29         mutex_unlock(&minors_idr_lock);
  30         return info;
  31 }
  32
  33 static int allocate_minor(struct ocxl_file_info *info)
  34 {
  35         int minor;
  36
  37         mutex_lock(&minors_idr_lock);
  38         minor = idr_alloc(&minors_idr, info, 0, OCXL_NUM_MINORS, GFP_KERNEL);
  39         mutex_unlock(&minors_idr_lock);
  40         return minor;
  41 }
  42
  43 static void free_minor(struct ocxl_file_info *info)
  44 {
  45         mutex_lock(&minors_idr_lock);
  46         idr_remove(&minors_idr, MINOR(info->dev.devt));
  47         mutex_unlock(&minors_idr_lock);
  48 }
  49
  50 static int afu_open(struct inode *inode, struct file *file)
  51 {
  52         struct ocxl_file_info *info;
  53         struct ocxl_context *ctx;
  54         int rc;
  55
  56         pr_debug("%s for device %x\n", __func__, inode->i_rdev);
  57
  58         info = find_and_get_file_info(inode->i_rdev);
  59         if (!info)
  60                 return -ENODEV;
  61
  62         rc = ocxl_context_alloc(&ctx, info->afu, inode->i_mapping);
  63         if (rc) {
  64                 put_device(&info->dev);
  65                 return rc;
  66         }
  67         put_device(&info->dev);
  68         file->private_data = ctx;
  69         return 0;
  70 }
  71
  72 static long afu_ioctl_attach(struct ocxl_context *ctx,
  73                         struct ocxl_ioctl_attach __user *uarg)
  74 {
  75         struct ocxl_ioctl_attach arg;
  76         u64 amr = 0;
  77         int rc;
  78
  79         pr_debug("%s for context %d\n", __func__, ctx->pasid);
  80
  81         if (copy_from_user(&arg, uarg, sizeof(arg)))
  82                 return -EFAULT;
  83
  84         /* Make sure reserved fields are not set for forward compatibility */
  85         if (arg.reserved1 || arg.reserved2 || arg.reserved3)
  86                 return -EINVAL;
  87
  88         amr = arg.amr & mfspr(SPRN_UAMOR);
  89         rc = ocxl_context_attach(ctx, amr, current->mm);
  90         return rc;
  91 }
  92
  93 static long afu_ioctl_get_metadata(struct ocxl_context *ctx,
  94                 struct ocxl_ioctl_metadata __user *uarg)
  95 {
  96         struct ocxl_ioctl_metadata arg;
  97
  98         memset(&arg, 0, sizeof(arg));
  99
 100         arg.version = 0;
 101
 102         arg.afu_version_major = ctx->afu->config.version_major;
 103         arg.afu_version_minor = ctx->afu->config.version_minor;
 104         arg.pasid = ctx->pasid;
 105         arg.pp_mmio_size = ctx->afu->config.pp_mmio_stride;
 106         arg.global_mmio_size = ctx->afu->config.global_mmio_size;
 107
 108         if (copy_to_user(uarg, &arg, sizeof(arg)))
 109                 return -EFAULT;
 110
 111         return 0;
 112 }
 113
 114 #ifdef CONFIG_PPC64
 115 static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
 116                 struct ocxl_ioctl_p9_wait __user *uarg)
 117 {
 118         struct ocxl_ioctl_p9_wait arg;
 119
 120         memset(&arg, 0, sizeof(arg));
 121
 122         if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
 123                 enum ocxl_context_status status;
 124
 125                 // Locks both status & tidr
 126                 mutex_lock(&ctx->status_mutex);
 127                 if (!ctx->tidr) {
 128                         if (set_thread_tidr(current)) {
 129                                 mutex_unlock(&ctx->status_mutex);
 130                                 return -ENOENT;
 131                         }
 132
 133                         ctx->tidr = current->thread.tidr;
 134                 }
 135
 136                 status = ctx->status;
 137                 mutex_unlock(&ctx->status_mutex);
 138
 139                 if (status == ATTACHED) {
 140                         int rc = ocxl_link_update_pe(ctx->afu->fn->link,
 141                                 ctx->pasid, ctx->tidr);
 142
 143                         if (rc)
 144                                 return rc;
 145                 }
 146
 147                 arg.thread_id = ctx->tidr;
 148         } else
 149                 return -ENOENT;
 150
 151         if (copy_to_user(uarg, &arg, sizeof(arg)))
 152                 return -EFAULT;
 153
 154         return 0;
 155 }
 156 #endif
 157
 158
 159 static long afu_ioctl_get_features(struct ocxl_context *ctx,
 160                 struct ocxl_ioctl_features __user *uarg)
 161 {
 162         struct ocxl_ioctl_features arg;
 163
 164         memset(&arg, 0, sizeof(arg));
 165
 166 #ifdef CONFIG_PPC64
 167         if (cpu_has_feature(CPU_FTR_P9_TIDR))
 168                 arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
 169 #endif
 170
 171         if (copy_to_user(uarg, &arg, sizeof(arg)))
 172                 return -EFAULT;
 173
 174         return 0;
 175 }
 176
 177 #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :                 \
 178                         x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :       \
 179                         x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" :         \
 180                         x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" :     \
 181                         x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" : \
 182                         x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" :     \
 183                         x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" : \
 184                         "UNKNOWN")
 185
 186 static irqreturn_t irq_handler(void *private)
 187 {
 188         struct eventfd_ctx *ev_ctx = private;
 189
 190         eventfd_signal(ev_ctx, 1);
 191         return IRQ_HANDLED;
 192 }
 193
 194 static void irq_free(void *private)
 195 {
 196         struct eventfd_ctx *ev_ctx = private;
 197
 198         eventfd_ctx_put(ev_ctx);
 199 }
 200
 201 static long afu_ioctl(struct file *file, unsigned int cmd,
 202                 unsigned long args)
 203 {
 204         struct ocxl_context *ctx = file->private_data;
 205         struct ocxl_ioctl_irq_fd irq_fd;
 206         struct eventfd_ctx *ev_ctx;
 207         int irq_id;
 208         u64 irq_offset;
 209         long rc;
 210         bool closed;
 211
 212         pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid,
 213                 CMD_STR(cmd));
 214
 215         mutex_lock(&ctx->status_mutex);
 216         closed = (ctx->status == CLOSED);
 217         mutex_unlock(&ctx->status_mutex);
 218
 219         if (closed)
 220                 return -EIO;
 221
 222         switch (cmd) {
 223         case OCXL_IOCTL_ATTACH:
 224                 rc = afu_ioctl_attach(ctx,
 225                                 (struct ocxl_ioctl_attach __user *) args);
 226                 break;
 227
 228         case OCXL_IOCTL_IRQ_ALLOC:
 229                 rc = ocxl_afu_irq_alloc(ctx, &irq_id);
 230                 if (!rc) {
 231                         irq_offset = ocxl_irq_id_to_offset(ctx, irq_id);
 232                         rc = copy_to_user((u64 __user *) args, &irq_offset,
 233                                         sizeof(irq_offset));
 234                         if (rc) {
 235                                 ocxl_afu_irq_free(ctx, irq_id);
 236                                 return -EFAULT;
 237                         }
 238                 }
 239                 break;
 240
 241         case OCXL_IOCTL_IRQ_FREE:
 242                 rc = copy_from_user(&irq_offset, (u64 __user *) args,
 243                                 sizeof(irq_offset));
 244                 if (rc)
 245                         return -EFAULT;
 246                 irq_id = ocxl_irq_offset_to_id(ctx, irq_offset);
 247                 rc = ocxl_afu_irq_free(ctx, irq_id);
 248                 break;
 249
 250         case OCXL_IOCTL_IRQ_SET_FD:
 251                 rc = copy_from_user(&irq_fd, (u64 __user *) args,
 252                                 sizeof(irq_fd));
 253                 if (rc)
 254                         return -EFAULT;
 255                 if (irq_fd.reserved)
 256                         return -EINVAL;
 257                 irq_id = ocxl_irq_offset_to_id(ctx, irq_fd.irq_offset);
 258                 ev_ctx = eventfd_ctx_fdget(irq_fd.eventfd);
 259                 if (IS_ERR(ev_ctx))
 260                         return PTR_ERR(ev_ctx);
 261                 rc = ocxl_irq_set_handler(ctx, irq_id, irq_handler, irq_free, ev_ctx);
 262                 break;
 263
 264         case OCXL_IOCTL_GET_METADATA:
 265                 rc = afu_ioctl_get_metadata(ctx,
 266                                 (struct ocxl_ioctl_metadata __user *) args);
 267                 break;
 268
 269 #ifdef CONFIG_PPC64
 270         case OCXL_IOCTL_ENABLE_P9_WAIT:
 271                 rc = afu_ioctl_enable_p9_wait(ctx,
 272                                 (struct ocxl_ioctl_p9_wait __user *) args);
 273                 break;
 274 #endif
 275
 276         case OCXL_IOCTL_GET_FEATURES:
 277                 rc = afu_ioctl_get_features(ctx,
 278                                 (struct ocxl_ioctl_features __user *) args);
 279                 break;
 280
 281         default:
 282                 rc = -EINVAL;
 283         }
 284         return rc;
 285 }
 286
 287 static long afu_compat_ioctl(struct file *file, unsigned int cmd,
 288                         unsigned long args)
 289 {
 290         return afu_ioctl(file, cmd, args);
 291 }
 292
 293 static int afu_mmap(struct file *file, struct vm_area_struct *vma)
 294 {
 295         struct ocxl_context *ctx = file->private_data;
 296
 297         pr_debug("%s for context %d\n", __func__, ctx->pasid);
 298         return ocxl_context_mmap(ctx, vma);
 299 }
 300
 301 static bool has_xsl_error(struct ocxl_context *ctx)
 302 {
 303         bool ret;
 304
 305         mutex_lock(&ctx->xsl_error_lock);
 306         ret = !!ctx->xsl_error.addr;
 307         mutex_unlock(&ctx->xsl_error_lock);
 308
 309         return ret;
 310 }
 311
 312 /*
 313  * Are there any events pending on the AFU
 314  * ctx: The AFU context
 315  * Returns: true if there are events pending
 316  */
 317 static bool afu_events_pending(struct ocxl_context *ctx)
 318 {
 319         if (has_xsl_error(ctx))
 320                 return true;
 321         return false;
 322 }
 323
 324 static unsigned int afu_poll(struct file *file, struct poll_table_struct *wait)
 325 {
 326         struct ocxl_context *ctx = file->private_data;
 327         unsigned int mask = 0;
 328         bool closed;
 329
 330         pr_debug("%s for context %d\n", __func__, ctx->pasid);
 331
 332         poll_wait(file, &ctx->events_wq, wait);
 333
 334         mutex_lock(&ctx->status_mutex);
 335         closed = (ctx->status == CLOSED);
 336         mutex_unlock(&ctx->status_mutex);
 337
 338         if (afu_events_pending(ctx))
 339                 mask = EPOLLIN | EPOLLRDNORM;
 340         else if (closed)
 341                 mask = EPOLLERR;
 342
 343         return mask;
 344 }
 345
 346 /*
 347  * Populate the supplied buffer with a single XSL error
 348  * ctx: The AFU context to report the error from
 349  * header: the event header to populate
 350  * buf: The buffer to write the body into (should be at least
 351  *      AFU_EVENT_BODY_XSL_ERROR_SIZE)
 352  * Return: the amount of buffer that was populated
 353  */
 354 static ssize_t append_xsl_error(struct ocxl_context *ctx,
 355                                 struct ocxl_kernel_event_header *header,
 356                                 char __user *buf)
 357 {
 358         struct ocxl_kernel_event_xsl_fault_error body;
 359
 360         memset(&body, 0, sizeof(body));
 361
 362         mutex_lock(&ctx->xsl_error_lock);
 363         if (!ctx->xsl_error.addr) {
 364                 mutex_unlock(&ctx->xsl_error_lock);
 365                 return 0;
 366         }
 367
 368         body.addr = ctx->xsl_error.addr;
 369         body.dsisr = ctx->xsl_error.dsisr;
 370         body.count = ctx->xsl_error.count;
 371
 372         ctx->xsl_error.addr = 0;
 373         ctx->xsl_error.dsisr = 0;
 374         ctx->xsl_error.count = 0;
 375
 376         mutex_unlock(&ctx->xsl_error_lock);
 377
 378         header->type = OCXL_AFU_EVENT_XSL_FAULT_ERROR;
 379
 380         if (copy_to_user(buf, &body, sizeof(body)))
 381                 return -EFAULT;
 382
 383         return sizeof(body);
 384 }
 385
 386 #define AFU_EVENT_BODY_MAX_SIZE sizeof(struct ocxl_kernel_event_xsl_fault_error)
 387
 388 /*
 389  * Reports events on the AFU
 390  * Format:
 391  *      Header (struct ocxl_kernel_event_header)
 392  *      Body (struct ocxl_kernel_event_*)
 393  *      Header...
 394  */
 395 static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
 396                         loff_t *off)
 397 {
 398         struct ocxl_context *ctx = file->private_data;
 399         struct ocxl_kernel_event_header header;
 400         ssize_t rc;
 401         ssize_t used = 0;
 402         DEFINE_WAIT(event_wait);
 403
 404         memset(&header, 0, sizeof(header));
 405
 406         /* Require offset to be 0 */
 407         if (*off != 0)
 408                 return -EINVAL;
 409
 410         if (count < (sizeof(struct ocxl_kernel_event_header) +
 411                         AFU_EVENT_BODY_MAX_SIZE))
 412                 return -EINVAL;
 413
 414         for (;;) {
 415                 prepare_to_wait(&ctx->events_wq, &event_wait,
 416                                 TASK_INTERRUPTIBLE);
 417
 418                 if (afu_events_pending(ctx))
 419                         break;
 420
 421                 if (ctx->status == CLOSED)
 422                         break;
 423
 424                 if (file->f_flags & O_NONBLOCK) {
 425                         finish_wait(&ctx->events_wq, &event_wait);
 426                         return -EAGAIN;
 427                 }
 428
 429                 if (signal_pending(current)) {
 430                         finish_wait(&ctx->events_wq, &event_wait);
 431                         return -ERESTARTSYS;
 432                 }
 433
 434                 schedule();
 435         }
 436
 437         finish_wait(&ctx->events_wq, &event_wait);
 438
 439         if (has_xsl_error(ctx)) {
 440                 used = append_xsl_error(ctx, &header, buf + sizeof(header));
 441                 if (used < 0)
 442                         return used;
 443         }
 444
 445         if (!afu_events_pending(ctx))
 446                 header.flags |= OCXL_KERNEL_EVENT_FLAG_LAST;
 447
 448         if (copy_to_user(buf, &header, sizeof(header)))
 449                 return -EFAULT;
 450
 451         used += sizeof(header);
 452
 453         rc = used;
 454         return rc;
 455 }
 456
 457 static int afu_release(struct inode *inode, struct file *file)
 458 {
 459         struct ocxl_context *ctx = file->private_data;
 460         int rc;
 461
 462         pr_debug("%s for device %x\n", __func__, inode->i_rdev);
 463         rc = ocxl_context_detach(ctx);
 464         mutex_lock(&ctx->mapping_lock);
 465         ctx->mapping = NULL;
 466         mutex_unlock(&ctx->mapping_lock);
 467         wake_up_all(&ctx->events_wq);
 468         if (rc != -EBUSY)
 469                 ocxl_context_free(ctx);
 470         return 0;
 471 }
 472
 473 static const struct file_operations ocxl_afu_fops = {
 474         .owner          = THIS_MODULE,
 475         .open           = afu_open,
 476         .unlocked_ioctl = afu_ioctl,
 477         .compat_ioctl   = afu_compat_ioctl,
 478         .mmap           = afu_mmap,
 479         .poll           = afu_poll,
 480         .read           = afu_read,
 481         .release        = afu_release,
 482 };
 483
 484 // Free the info struct
 485 static void info_release(struct device *dev)
 486 {
 487         struct ocxl_file_info *info = container_of(dev, struct ocxl_file_info, dev);
 488
 489         ocxl_afu_put(info->afu);
 490         kfree(info);
 491 }
 492
 493 static int ocxl_file_make_visible(struct ocxl_file_info *info)
 494 {
 495         int rc;
 496
 497         cdev_init(&info->cdev, &ocxl_afu_fops);
 498         rc = cdev_add(&info->cdev, info->dev.devt, 1);
 499         if (rc) {
 500                 dev_err(&info->dev, "Unable to add afu char device: %d\n", rc);
 501                 return rc;
 502         }
 503
 504         return 0;
 505 }
 506
 507 static void ocxl_file_make_invisible(struct ocxl_file_info *info)
 508 {
 509         cdev_del(&info->cdev);
 510 }
 511
 512 int ocxl_file_register_afu(struct ocxl_afu *afu)
 513 {
 514         int minor;
 515         int rc;
 516         struct ocxl_file_info *info;
 517         struct ocxl_fn *fn = afu->fn;
 518         struct pci_dev *pci_dev = to_pci_dev(fn->dev.parent);
 519
 520         info = kzalloc(sizeof(*info), GFP_KERNEL);
 521         if (info == NULL)
 522                 return -ENOMEM;
 523
 524         minor = allocate_minor(info);
 525         if (minor < 0) {
 526                 kfree(info);
 527                 return minor;
 528         }
 529
 530         info->dev.parent = &fn->dev;
 531         info->dev.devt = MKDEV(MAJOR(ocxl_dev), minor);
 532         info->dev.class = ocxl_class;
 533         info->dev.release = info_release;
 534
 535         info->afu = afu;
 536         ocxl_afu_get(afu);
 537
 538         rc = dev_set_name(&info->dev, "%s.%s.%hhu",
 539                 afu->config.name, dev_name(&pci_dev->dev), afu->config.idx);
 540         if (rc)
 541                 goto err_put;
 542
 543         rc = device_register(&info->dev);
 544         if (rc)
 545                 goto err_put;
 546
 547         rc = ocxl_sysfs_register_afu(info);
 548         if (rc)
 549                 goto err_unregister;
 550
 551         rc = ocxl_file_make_visible(info);
 552         if (rc)
 553                 goto err_unregister;
 554
 555         ocxl_afu_set_private(afu, info);
 556
 557         return 0;
 558
 559 err_unregister:
 560         ocxl_sysfs_unregister_afu(info); // safe to call even if register failed
 561         device_unregister(&info->dev);
 562 err_put:
 563         ocxl_afu_put(afu);
 564         free_minor(info);
 565         kfree(info);
 566         return rc;
 567 }
 568
 569 void ocxl_file_unregister_afu(struct ocxl_afu *afu)
 570 {
 571         struct ocxl_file_info *info = ocxl_afu_get_private(afu);
 572
 573         if (!info)
 574                 return;
 575
 576         ocxl_file_make_invisible(info);
 577         ocxl_sysfs_unregister_afu(info);
 578         free_minor(info);
 579         device_unregister(&info->dev);
 580 }
 581
 582 static char *ocxl_devnode(struct device *dev, umode_t *mode)
 583 {
 584         return kasprintf(GFP_KERNEL, "ocxl/%s", dev_name(dev));
 585 }
 586
 587 int ocxl_file_init(void)
 588 {
 589         int rc;
 590
 591         mutex_init(&minors_idr_lock);
 592         idr_init(&minors_idr);
 593
 594         rc = alloc_chrdev_region(&ocxl_dev, 0, OCXL_NUM_MINORS, "ocxl");
 595         if (rc) {
 596                 pr_err("Unable to allocate ocxl major number: %d\n", rc);
 597                 return rc;
 598         }
 599
 600         ocxl_class = class_create(THIS_MODULE, "ocxl");
 601         if (IS_ERR(ocxl_class)) {
 602                 pr_err("Unable to create ocxl class\n");
 603                 unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
 604                 return PTR_ERR(ocxl_class);
 605         }
 606
 607         ocxl_class->devnode = ocxl_devnode;
 608         return 0;
 609 }
 610
 611 void ocxl_file_exit(void)
 612 {
 613         class_destroy(ocxl_class);
 614         unregister_chrdev_region(ocxl_dev, OCXL_NUM_MINORS);
 615         idr_destroy(&minors_idr);
 616 }