drivers/misc/cxl/api.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2014 IBM Corp.
   4  */
   5
   6 #include <linux/pci.h>
   7 #include <linux/slab.h>
   8 #include <linux/file.h>
   9 #include <misc/cxl.h>
  10 #include <linux/module.h>
  11 #include <linux/mount.h>
  12 #include <linux/pseudo_fs.h>
  13 #include <linux/sched/mm.h>
  14 #include <linux/mmu_context.h>
  15 #include <linux/irqdomain.h>
  16
  17 #include "cxl.h"
  18
  19 /*
  20  * Since we want to track memory mappings to be able to force-unmap
  21  * when the AFU is no longer reachable, we need an inode. For devices
  22  * opened through the cxl user API, this is not a problem, but a
  23  * userland process can also get a cxl fd through the cxl_get_fd()
  24  * API, which is used by the cxlflash driver.
  25  *
  26  * Therefore we implement our own simple pseudo-filesystem and inode
  27  * allocator. We don't use the anonymous inode, as we need the
  28  * meta-data associated with it (address_space) and it is shared by
  29  * other drivers/processes, so it could lead to cxl unmapping VMAs
  30  * from random processes.
  31  */
  32
  33 #define CXL_PSEUDO_FS_MAGIC     0x1697697f
  34
  35 static int cxl_fs_cnt;
  36 static struct vfsmount *cxl_vfs_mount;
  37
  38 static int cxl_fs_init_fs_context(struct fs_context *fc)
  39 {
  40         return init_pseudo(fc, CXL_PSEUDO_FS_MAGIC) ? 0 : -ENOMEM;
  41 }
  42
  43 static struct file_system_type cxl_fs_type = {
  44         .name           = "cxl",
  45         .owner          = THIS_MODULE,
  46         .init_fs_context = cxl_fs_init_fs_context,
  47         .kill_sb        = kill_anon_super,
  48 };
  49
  50
  51 void cxl_release_mapping(struct cxl_context *ctx)
  52 {
  53         if (ctx->kernelapi && ctx->mapping)
  54                 simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
  55 }
  56
  57 static struct file *cxl_getfile(const char *name,
  58                                 const struct file_operations *fops,
  59                                 void *priv, int flags)
  60 {
  61         struct file *file;
  62         struct inode *inode;
  63         int rc;
  64
  65         /* strongly inspired by anon_inode_getfile() */
  66
  67         if (fops->owner && !try_module_get(fops->owner))
  68                 return ERR_PTR(-ENOENT);
  69
  70         rc = simple_pin_fs(&cxl_fs_type, &cxl_vfs_mount, &cxl_fs_cnt);
  71         if (rc < 0) {
  72                 pr_err("Cannot mount cxl pseudo filesystem: %d\n", rc);
  73                 file = ERR_PTR(rc);
  74                 goto err_module;
  75         }
  76
  77         inode = alloc_anon_inode(cxl_vfs_mount->mnt_sb);
  78         if (IS_ERR(inode)) {
  79                 file = ERR_CAST(inode);
  80                 goto err_fs;
  81         }
  82
  83         file = alloc_file_pseudo(inode, cxl_vfs_mount, name,
  84                                  flags & (O_ACCMODE | O_NONBLOCK), fops);
  85         if (IS_ERR(file))
  86                 goto err_inode;
  87
  88         file->private_data = priv;
  89
  90         return file;
  91
  92 err_inode:
  93         iput(inode);
  94 err_fs:
  95         simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
  96 err_module:
  97         module_put(fops->owner);
  98         return file;
  99 }
 100
 101 struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
 102 {
 103         struct cxl_afu *afu;
 104         struct cxl_context  *ctx;
 105         int rc;
 106
 107         afu = cxl_pci_to_afu(dev);
 108         if (IS_ERR(afu))
 109                 return ERR_CAST(afu);
 110
 111         ctx = cxl_context_alloc();
 112         if (!ctx)
 113                 return ERR_PTR(-ENOMEM);
 114
 115         ctx->kernelapi = true;
 116
 117         /* Make it a slave context.  We can promote it later? */
 118         rc = cxl_context_init(ctx, afu, false);
 119         if (rc)
 120                 goto err_ctx;
 121
 122         return ctx;
 123
 124 err_ctx:
 125         kfree(ctx);
 126         return ERR_PTR(rc);
 127 }
 128 EXPORT_SYMBOL_GPL(cxl_dev_context_init);
 129
 130 struct cxl_context *cxl_get_context(struct pci_dev *dev)
 131 {
 132         return dev->dev.archdata.cxl_ctx;
 133 }
 134 EXPORT_SYMBOL_GPL(cxl_get_context);
 135
 136 int cxl_release_context(struct cxl_context *ctx)
 137 {
 138         if (ctx->status >= STARTED)
 139                 return -EBUSY;
 140
 141         cxl_context_free(ctx);
 142
 143         return 0;
 144 }
 145 EXPORT_SYMBOL_GPL(cxl_release_context);
 146
 147 static irq_hw_number_t cxl_find_afu_irq(struct cxl_context *ctx, int num)
 148 {
 149         __u16 range;
 150         int r;
 151
 152         for (r = 0; r < CXL_IRQ_RANGES; r++) {
 153                 range = ctx->irqs.range[r];
 154                 if (num < range) {
 155                         return ctx->irqs.offset[r] + num;
 156                 }
 157                 num -= range;
 158         }
 159         return 0;
 160 }
 161
 162
 163 int cxl_set_priv(struct cxl_context *ctx, void *priv)
 164 {
 165         if (!ctx)
 166                 return -EINVAL;
 167
 168         ctx->priv = priv;
 169
 170         return 0;
 171 }
 172 EXPORT_SYMBOL_GPL(cxl_set_priv);
 173
 174 void *cxl_get_priv(struct cxl_context *ctx)
 175 {
 176         if (!ctx)
 177                 return ERR_PTR(-EINVAL);
 178
 179         return ctx->priv;
 180 }
 181 EXPORT_SYMBOL_GPL(cxl_get_priv);
 182
 183 int cxl_allocate_afu_irqs(struct cxl_context *ctx, int num)
 184 {
 185         int res;
 186         irq_hw_number_t hwirq;
 187
 188         if (num == 0)
 189                 num = ctx->afu->pp_irqs;
 190         res = afu_allocate_irqs(ctx, num);
 191         if (res)
 192                 return res;
 193
 194         if (!cpu_has_feature(CPU_FTR_HVMODE)) {
 195                 /* In a guest, the PSL interrupt is not multiplexed. It was
 196                  * allocated above, and we need to set its handler
 197                  */
 198                 hwirq = cxl_find_afu_irq(ctx, 0);
 199                 if (hwirq)
 200                         cxl_map_irq(ctx->afu->adapter, hwirq, cxl_ops->psl_interrupt, ctx, "psl");
 201         }
 202
 203         if (ctx->status == STARTED) {
 204                 if (cxl_ops->update_ivtes)
 205                         cxl_ops->update_ivtes(ctx);
 206                 else WARN(1, "BUG: cxl_allocate_afu_irqs must be called prior to starting the context on this platform\n");
 207         }
 208
 209         return res;
 210 }
 211 EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
 212
 213 void cxl_free_afu_irqs(struct cxl_context *ctx)
 214 {
 215         irq_hw_number_t hwirq;
 216         unsigned int virq;
 217
 218         if (!cpu_has_feature(CPU_FTR_HVMODE)) {
 219                 hwirq = cxl_find_afu_irq(ctx, 0);
 220                 if (hwirq) {
 221                         virq = irq_find_mapping(NULL, hwirq);
 222                         if (virq)
 223                                 cxl_unmap_irq(virq, ctx);
 224                 }
 225         }
 226         afu_irq_name_free(ctx);
 227         cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
 228 }
 229 EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
 230
 231 int cxl_map_afu_irq(struct cxl_context *ctx, int num,
 232                     irq_handler_t handler, void *cookie, char *name)
 233 {
 234         irq_hw_number_t hwirq;
 235
 236         /*
 237          * Find interrupt we are to register.
 238          */
 239         hwirq = cxl_find_afu_irq(ctx, num);
 240         if (!hwirq)
 241                 return -ENOENT;
 242
 243         return cxl_map_irq(ctx->afu->adapter, hwirq, handler, cookie, name);
 244 }
 245 EXPORT_SYMBOL_GPL(cxl_map_afu_irq);
 246
 247 void cxl_unmap_afu_irq(struct cxl_context *ctx, int num, void *cookie)
 248 {
 249         irq_hw_number_t hwirq;
 250         unsigned int virq;
 251
 252         hwirq = cxl_find_afu_irq(ctx, num);
 253         if (!hwirq)
 254                 return;
 255
 256         virq = irq_find_mapping(NULL, hwirq);
 257         if (virq)
 258                 cxl_unmap_irq(virq, cookie);
 259 }
 260 EXPORT_SYMBOL_GPL(cxl_unmap_afu_irq);
 261
 262 /*
 263  * Start a context
 264  * Code here similar to afu_ioctl_start_work().
 265  */
 266 int cxl_start_context(struct cxl_context *ctx, u64 wed,
 267                       struct task_struct *task)
 268 {
 269         int rc = 0;
 270         bool kernel = true;
 271
 272         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 273
 274         mutex_lock(&ctx->status_mutex);
 275         if (ctx->status == STARTED)
 276                 goto out; /* already started */
 277
 278         /*
 279          * Increment the mapped context count for adapter. This also checks
 280          * if adapter_context_lock is taken.
 281          */
 282         rc = cxl_adapter_context_get(ctx->afu->adapter);
 283         if (rc)
 284                 goto out;
 285
 286         if (task) {
 287                 ctx->pid = get_task_pid(task, PIDTYPE_PID);
 288                 kernel = false;
 289
 290                 /* acquire a reference to the task's mm */
 291                 ctx->mm = get_task_mm(current);
 292
 293                 /* ensure this mm_struct can't be freed */
 294                 cxl_context_mm_count_get(ctx);
 295
 296                 if (ctx->mm) {
 297                         /* decrement the use count from above */
 298                         mmput(ctx->mm);
 299                         /* make TLBIs for this context global */
 300                         mm_context_add_copro(ctx->mm);
 301                 }
 302         }
 303
 304         /*
 305          * Increment driver use count. Enables global TLBIs for hash
 306          * and callbacks to handle the segment table
 307          */
 308         cxl_ctx_get();
 309
 310         /* See the comment in afu_ioctl_start_work() */
 311         smp_mb();
 312
 313         if ((rc = cxl_ops->attach_process(ctx, kernel, wed, 0))) {
 314                 put_pid(ctx->pid);
 315                 ctx->pid = NULL;
 316                 cxl_adapter_context_put(ctx->afu->adapter);
 317                 cxl_ctx_put();
 318                 if (task) {
 319                         cxl_context_mm_count_put(ctx);
 320                         if (ctx->mm)
 321                                 mm_context_remove_copro(ctx->mm);
 322                 }
 323                 goto out;
 324         }
 325
 326         ctx->status = STARTED;
 327 out:
 328         mutex_unlock(&ctx->status_mutex);
 329         return rc;
 330 }
 331 EXPORT_SYMBOL_GPL(cxl_start_context);
 332
 333 int cxl_process_element(struct cxl_context *ctx)
 334 {
 335         return ctx->external_pe;
 336 }
 337 EXPORT_SYMBOL_GPL(cxl_process_element);
 338
 339 /* Stop a context.  Returns 0 on success, otherwise -Errno */
 340 int cxl_stop_context(struct cxl_context *ctx)
 341 {
 342         return __detach_context(ctx);
 343 }
 344 EXPORT_SYMBOL_GPL(cxl_stop_context);
 345
 346 void cxl_set_master(struct cxl_context *ctx)
 347 {
 348         ctx->master = true;
 349 }
 350 EXPORT_SYMBOL_GPL(cxl_set_master);
 351
 352 /* wrappers around afu_* file ops which are EXPORTED */
 353 int cxl_fd_open(struct inode *inode, struct file *file)
 354 {
 355         return afu_open(inode, file);
 356 }
 357 EXPORT_SYMBOL_GPL(cxl_fd_open);
 358 int cxl_fd_release(struct inode *inode, struct file *file)
 359 {
 360         return afu_release(inode, file);
 361 }
 362 EXPORT_SYMBOL_GPL(cxl_fd_release);
 363 long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 364 {
 365         return afu_ioctl(file, cmd, arg);
 366 }
 367 EXPORT_SYMBOL_GPL(cxl_fd_ioctl);
 368 int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm)
 369 {
 370         return afu_mmap(file, vm);
 371 }
 372 EXPORT_SYMBOL_GPL(cxl_fd_mmap);
 373 __poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll)
 374 {
 375         return afu_poll(file, poll);
 376 }
 377 EXPORT_SYMBOL_GPL(cxl_fd_poll);
 378 ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
 379                         loff_t *off)
 380 {
 381         return afu_read(file, buf, count, off);
 382 }
 383 EXPORT_SYMBOL_GPL(cxl_fd_read);
 384
 385 #define PATCH_FOPS(NAME) if (!fops->NAME) fops->NAME = afu_fops.NAME
 386
 387 /* Get a struct file and fd for a context and attach the ops */
 388 struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
 389                         int *fd)
 390 {
 391         struct file *file;
 392         int rc, flags, fdtmp;
 393         char *name = NULL;
 394
 395         /* only allow one per context */
 396         if (ctx->mapping)
 397                 return ERR_PTR(-EEXIST);
 398
 399         flags = O_RDWR | O_CLOEXEC;
 400
 401         /* This code is similar to anon_inode_getfd() */
 402         rc = get_unused_fd_flags(flags);
 403         if (rc < 0)
 404                 return ERR_PTR(rc);
 405         fdtmp = rc;
 406
 407         /*
 408          * Patch the file ops.  Needs to be careful that this is rentrant safe.
 409          */
 410         if (fops) {
 411                 PATCH_FOPS(open);
 412                 PATCH_FOPS(poll);
 413                 PATCH_FOPS(read);
 414                 PATCH_FOPS(release);
 415                 PATCH_FOPS(unlocked_ioctl);
 416                 PATCH_FOPS(compat_ioctl);
 417                 PATCH_FOPS(mmap);
 418         } else /* use default ops */
 419                 fops = (struct file_operations *)&afu_fops;
 420
 421         name = kasprintf(GFP_KERNEL, "cxl:%d", ctx->pe);
 422         file = cxl_getfile(name, fops, ctx, flags);
 423         kfree(name);
 424         if (IS_ERR(file))
 425                 goto err_fd;
 426
 427         cxl_context_set_mapping(ctx, file->f_mapping);
 428         *fd = fdtmp;
 429         return file;
 430
 431 err_fd:
 432         put_unused_fd(fdtmp);
 433         return NULL;
 434 }
 435 EXPORT_SYMBOL_GPL(cxl_get_fd);
 436
 437 struct cxl_context *cxl_fops_get_context(struct file *file)
 438 {
 439         return file->private_data;
 440 }
 441 EXPORT_SYMBOL_GPL(cxl_fops_get_context);
 442
 443 void cxl_set_driver_ops(struct cxl_context *ctx,
 444                         struct cxl_afu_driver_ops *ops)
 445 {
 446         WARN_ON(!ops->fetch_event || !ops->event_delivered);
 447         atomic_set(&ctx->afu_driver_events, 0);
 448         ctx->afu_driver_ops = ops;
 449 }
 450 EXPORT_SYMBOL_GPL(cxl_set_driver_ops);
 451
 452 void cxl_context_events_pending(struct cxl_context *ctx,
 453                                 unsigned int new_events)
 454 {
 455         atomic_add(new_events, &ctx->afu_driver_events);
 456         wake_up_all(&ctx->wq);
 457 }
 458 EXPORT_SYMBOL_GPL(cxl_context_events_pending);
 459
 460 int cxl_start_work(struct cxl_context *ctx,
 461                    struct cxl_ioctl_start_work *work)
 462 {
 463         int rc;
 464
 465         /* code taken from afu_ioctl_start_work */
 466         if (!(work->flags & CXL_START_WORK_NUM_IRQS))
 467                 work->num_interrupts = ctx->afu->pp_irqs;
 468         else if ((work->num_interrupts < ctx->afu->pp_irqs) ||
 469                  (work->num_interrupts > ctx->afu->irqs_max)) {
 470                 return -EINVAL;
 471         }
 472
 473         rc = afu_register_irqs(ctx, work->num_interrupts);
 474         if (rc)
 475                 return rc;
 476
 477         rc = cxl_start_context(ctx, work->work_element_descriptor, current);
 478         if (rc < 0) {
 479                 afu_release_irqs(ctx, ctx);
 480                 return rc;
 481         }
 482
 483         return 0;
 484 }
 485 EXPORT_SYMBOL_GPL(cxl_start_work);
 486
 487 void __iomem *cxl_psa_map(struct cxl_context *ctx)
 488 {
 489         if (ctx->status != STARTED)
 490                 return NULL;
 491
 492         pr_devel("%s: psn_phys%llx size:%llx\n",
 493                 __func__, ctx->psn_phys, ctx->psn_size);
 494         return ioremap(ctx->psn_phys, ctx->psn_size);
 495 }
 496 EXPORT_SYMBOL_GPL(cxl_psa_map);
 497
 498 void cxl_psa_unmap(void __iomem *addr)
 499 {
 500         iounmap(addr);
 501 }
 502 EXPORT_SYMBOL_GPL(cxl_psa_unmap);
 503
 504 int cxl_afu_reset(struct cxl_context *ctx)
 505 {
 506         struct cxl_afu *afu = ctx->afu;
 507         int rc;
 508
 509         rc = cxl_ops->afu_reset(afu);
 510         if (rc)
 511                 return rc;
 512
 513         return cxl_ops->afu_check_and_enable(afu);
 514 }
 515 EXPORT_SYMBOL_GPL(cxl_afu_reset);
 516
 517 void cxl_perst_reloads_same_image(struct cxl_afu *afu,
 518                                   bool perst_reloads_same_image)
 519 {
 520         afu->adapter->perst_same_image = perst_reloads_same_image;
 521 }
 522 EXPORT_SYMBOL_GPL(cxl_perst_reloads_same_image);
 523
 524 ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count)
 525 {
 526         struct cxl_afu *afu = cxl_pci_to_afu(dev);
 527         if (IS_ERR(afu))
 528                 return -ENODEV;
 529
 530         return cxl_ops->read_adapter_vpd(afu->adapter, buf, count);
 531 }
 532 EXPORT_SYMBOL_GPL(cxl_read_adapter_vpd);