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