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/sched/mm.h>
  13 #include <linux/mmu_context.h>
  14
  15 #include "cxl.h"
  16
  17 /*
  18  * Since we want to track memory mappings to be able to force-unmap
  19  * when the AFU is no longer reachable, we need an inode. For devices
  20  * opened through the cxl user API, this is not a problem, but a
  21  * userland process can also get a cxl fd through the cxl_get_fd()
  22  * API, which is used by the cxlflash driver.
  23  *
  24  * Therefore we implement our own simple pseudo-filesystem and inode
  25  * allocator. We don't use the anonymous inode, as we need the
  26  * meta-data associated with it (address_space) and it is shared by
  27  * other drivers/processes, so it could lead to cxl unmapping VMAs
  28  * from random processes.
  29  */
  30
  31 #define CXL_PSEUDO_FS_MAGIC     0x1697697f
  32
  33 static int cxl_fs_cnt;
  34 static struct vfsmount *cxl_vfs_mount;
  35
  36 static const struct dentry_operations cxl_fs_dops = {
  37         .d_dname        = simple_dname,
  38 };
  39
  40 static struct dentry *cxl_fs_mount(struct file_system_type *fs_type, int flags,
  41                                 const char *dev_name, void *data)
  42 {
  43         return mount_pseudo(fs_type, "cxl:", NULL, &cxl_fs_dops,
  44                         CXL_PSEUDO_FS_MAGIC);
  45 }
  46
  47 static struct file_system_type cxl_fs_type = {
  48         .name           = "cxl",
  49         .owner          = THIS_MODULE,
  50         .mount          = cxl_fs_mount,
  51         .kill_sb        = kill_anon_super,
  52 };
  53
  54
  55 void cxl_release_mapping(struct cxl_context *ctx)
  56 {
  57         if (ctx->kernelapi && ctx->mapping)
  58                 simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
  59 }
  60
  61 static struct file *cxl_getfile(const char *name,
  62                                 const struct file_operations *fops,
  63                                 void *priv, int flags)
  64 {
  65         struct file *file;
  66         struct inode *inode;
  67         int rc;
  68
  69         /* strongly inspired by anon_inode_getfile() */
  70
  71         if (fops->owner && !try_module_get(fops->owner))
  72                 return ERR_PTR(-ENOENT);
  73
  74         rc = simple_pin_fs(&cxl_fs_type, &cxl_vfs_mount, &cxl_fs_cnt);
  75         if (rc < 0) {
  76                 pr_err("Cannot mount cxl pseudo filesystem: %d\n", rc);
  77                 file = ERR_PTR(rc);
  78                 goto err_module;
  79         }
  80
  81         inode = alloc_anon_inode(cxl_vfs_mount->mnt_sb);
  82         if (IS_ERR(inode)) {
  83                 file = ERR_CAST(inode);
  84                 goto err_fs;
  85         }
  86
  87         file = alloc_file_pseudo(inode, cxl_vfs_mount, name,
  88                                  flags & (O_ACCMODE | O_NONBLOCK), fops);
  89         if (IS_ERR(file))
  90                 goto err_inode;
  91
  92         file->private_data = priv;
  93
  94         return file;
  95
  96 err_inode:
  97         iput(inode);
  98 err_fs:
  99         simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
 100 err_module:
 101         module_put(fops->owner);
 102         return file;
 103 }
 104
 105 struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
 106 {
 107         struct cxl_afu *afu;
 108         struct cxl_context  *ctx;
 109         int rc;
 110
 111         afu = cxl_pci_to_afu(dev);
 112         if (IS_ERR(afu))
 113                 return ERR_CAST(afu);
 114
 115         ctx = cxl_context_alloc();
 116         if (!ctx)
 117                 return ERR_PTR(-ENOMEM);
 118
 119         ctx->kernelapi = true;
 120
 121         /* Make it a slave context.  We can promote it later? */
 122         rc = cxl_context_init(ctx, afu, false);
 123         if (rc)
 124                 goto err_ctx;
 125
 126         return ctx;
 127
 128 err_ctx:
 129         kfree(ctx);
 130         return ERR_PTR(rc);
 131 }
 132 EXPORT_SYMBOL_GPL(cxl_dev_context_init);
 133
 134 struct cxl_context *cxl_get_context(struct pci_dev *dev)
 135 {
 136         return dev->dev.archdata.cxl_ctx;
 137 }
 138 EXPORT_SYMBOL_GPL(cxl_get_context);
 139
 140 int cxl_release_context(struct cxl_context *ctx)
 141 {
 142         if (ctx->status >= STARTED)
 143                 return -EBUSY;
 144
 145         cxl_context_free(ctx);
 146
 147         return 0;
 148 }
 149 EXPORT_SYMBOL_GPL(cxl_release_context);
 150
 151 static irq_hw_number_t cxl_find_afu_irq(struct cxl_context *ctx, int num)
 152 {
 153         __u16 range;
 154         int r;
 155
 156         for (r = 0; r < CXL_IRQ_RANGES; r++) {
 157                 range = ctx->irqs.range[r];
 158                 if (num < range) {
 159                         return ctx->irqs.offset[r] + num;
 160                 }
 161                 num -= range;
 162         }
 163         return 0;
 164 }
 165
 166
 167 int cxl_set_priv(struct cxl_context *ctx, void *priv)
 168 {
 169         if (!ctx)
 170                 return -EINVAL;
 171
 172         ctx->priv = priv;
 173
 174         return 0;
 175 }
 176 EXPORT_SYMBOL_GPL(cxl_set_priv);
 177
 178 void *cxl_get_priv(struct cxl_context *ctx)
 179 {
 180         if (!ctx)
 181                 return ERR_PTR(-EINVAL);
 182
 183         return ctx->priv;
 184 }
 185 EXPORT_SYMBOL_GPL(cxl_get_priv);
 186
 187 int cxl_allocate_afu_irqs(struct cxl_context *ctx, int num)
 188 {
 189         int res;
 190         irq_hw_number_t hwirq;
 191
 192         if (num == 0)
 193                 num = ctx->afu->pp_irqs;
 194         res = afu_allocate_irqs(ctx, num);
 195         if (res)
 196                 return res;
 197
 198         if (!cpu_has_feature(CPU_FTR_HVMODE)) {
 199                 /* In a guest, the PSL interrupt is not multiplexed. It was
 200                  * allocated above, and we need to set its handler
 201                  */
 202                 hwirq = cxl_find_afu_irq(ctx, 0);
 203                 if (hwirq)
 204                         cxl_map_irq(ctx->afu->adapter, hwirq, cxl_ops->psl_interrupt, ctx, "psl");
 205         }
 206
 207         if (ctx->status == STARTED) {
 208                 if (cxl_ops->update_ivtes)
 209                         cxl_ops->update_ivtes(ctx);
 210                 else WARN(1, "BUG: cxl_allocate_afu_irqs must be called prior to starting the context on this platform\n");
 211         }
 212
 213         return res;
 214 }
 215 EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
 216
 217 void cxl_free_afu_irqs(struct cxl_context *ctx)
 218 {
 219         irq_hw_number_t hwirq;
 220         unsigned int virq;
 221
 222         if (!cpu_has_feature(CPU_FTR_HVMODE)) {
 223                 hwirq = cxl_find_afu_irq(ctx, 0);
 224                 if (hwirq) {
 225                         virq = irq_find_mapping(NULL, hwirq);
 226                         if (virq)
 227                                 cxl_unmap_irq(virq, ctx);
 228                 }
 229         }
 230         afu_irq_name_free(ctx);
 231         cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
 232 }
 233 EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
 234
 235 int cxl_map_afu_irq(struct cxl_context *ctx, int num,
 236                     irq_handler_t handler, void *cookie, char *name)
 237 {
 238         irq_hw_number_t hwirq;
 239
 240         /*
 241          * Find interrupt we are to register.
 242          */
 243         hwirq = cxl_find_afu_irq(ctx, num);
 244         if (!hwirq)
 245                 return -ENOENT;
 246
 247         return cxl_map_irq(ctx->afu->adapter, hwirq, handler, cookie, name);
 248 }
 249 EXPORT_SYMBOL_GPL(cxl_map_afu_irq);
 250
 251 void cxl_unmap_afu_irq(struct cxl_context *ctx, int num, void *cookie)
 252 {
 253         irq_hw_number_t hwirq;
 254         unsigned int virq;
 255
 256         hwirq = cxl_find_afu_irq(ctx, num);
 257         if (!hwirq)
 258                 return;
 259
 260         virq = irq_find_mapping(NULL, hwirq);
 261         if (virq)
 262                 cxl_unmap_irq(virq, cookie);
 263 }
 264 EXPORT_SYMBOL_GPL(cxl_unmap_afu_irq);
 265
 266 /*
 267  * Start a context
 268  * Code here similar to afu_ioctl_start_work().
 269  */
 270 int cxl_start_context(struct cxl_context *ctx, u64 wed,
 271                       struct task_struct *task)
 272 {
 273         int rc = 0;
 274         bool kernel = true;
 275
 276         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 277
 278         mutex_lock(&ctx->status_mutex);
 279         if (ctx->status == STARTED)
 280                 goto out; /* already started */
 281
 282         /*
 283          * Increment the mapped context count for adapter. This also checks
 284          * if adapter_context_lock is taken.
 285          */
 286         rc = cxl_adapter_context_get(ctx->afu->adapter);
 287         if (rc)
 288                 goto out;
 289
 290         if (task) {
 291                 ctx->pid = get_task_pid(task, PIDTYPE_PID);
 292                 kernel = false;
 293
 294                 /* acquire a reference to the task's mm */
 295                 ctx->mm = get_task_mm(current);
 296
 297                 /* ensure this mm_struct can't be freed */
 298                 cxl_context_mm_count_get(ctx);
 299
 300                 if (ctx->mm) {
 301                         /* decrement the use count from above */
 302                         mmput(ctx->mm);
 303                         /* make TLBIs for this context global */
 304                         mm_context_add_copro(ctx->mm);
 305                 }
 306         }
 307
 308         /*
 309          * Increment driver use count. Enables global TLBIs for hash
 310          * and callbacks to handle the segment table
 311          */
 312         cxl_ctx_get();
 313
 314         /* See the comment in afu_ioctl_start_work() */
 315         smp_mb();
 316
 317         if ((rc = cxl_ops->attach_process(ctx, kernel, wed, 0))) {
 318                 put_pid(ctx->pid);
 319                 ctx->pid = NULL;
 320                 cxl_adapter_context_put(ctx->afu->adapter);
 321                 cxl_ctx_put();
 322                 if (task) {
 323                         cxl_context_mm_count_put(ctx);
 324                         if (ctx->mm)
 325                                 mm_context_remove_copro(ctx->mm);
 326                 }
 327                 goto out;
 328         }
 329
 330         ctx->status = STARTED;
 331 out:
 332         mutex_unlock(&ctx->status_mutex);
 333         return rc;
 334 }
 335 EXPORT_SYMBOL_GPL(cxl_start_context);
 336
 337 int cxl_process_element(struct cxl_context *ctx)
 338 {
 339         return ctx->external_pe;
 340 }
 341 EXPORT_SYMBOL_GPL(cxl_process_element);
 342
 343 /* Stop a context.  Returns 0 on success, otherwise -Errno */
 344 int cxl_stop_context(struct cxl_context *ctx)
 345 {
 346         return __detach_context(ctx);
 347 }
 348 EXPORT_SYMBOL_GPL(cxl_stop_context);
 349
 350 void cxl_set_master(struct cxl_context *ctx)
 351 {
 352         ctx->master = true;
 353 }
 354 EXPORT_SYMBOL_GPL(cxl_set_master);
 355
 356 /* wrappers around afu_* file ops which are EXPORTED */
 357 int cxl_fd_open(struct inode *inode, struct file *file)
 358 {
 359         return afu_open(inode, file);
 360 }
 361 EXPORT_SYMBOL_GPL(cxl_fd_open);
 362 int cxl_fd_release(struct inode *inode, struct file *file)
 363 {
 364         return afu_release(inode, file);
 365 }
 366 EXPORT_SYMBOL_GPL(cxl_fd_release);
 367 long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 368 {
 369         return afu_ioctl(file, cmd, arg);
 370 }
 371 EXPORT_SYMBOL_GPL(cxl_fd_ioctl);
 372 int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm)
 373 {
 374         return afu_mmap(file, vm);
 375 }
 376 EXPORT_SYMBOL_GPL(cxl_fd_mmap);
 377 __poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll)
 378 {
 379         return afu_poll(file, poll);
 380 }
 381 EXPORT_SYMBOL_GPL(cxl_fd_poll);
 382 ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
 383                         loff_t *off)
 384 {
 385         return afu_read(file, buf, count, off);
 386 }
 387 EXPORT_SYMBOL_GPL(cxl_fd_read);
 388
 389 #define PATCH_FOPS(NAME) if (!fops->NAME) fops->NAME = afu_fops.NAME
 390
 391 /* Get a struct file and fd for a context and attach the ops */
 392 struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
 393                         int *fd)
 394 {
 395         struct file *file;
 396         int rc, flags, fdtmp;
 397         char *name = NULL;
 398
 399         /* only allow one per context */
 400         if (ctx->mapping)
 401                 return ERR_PTR(-EEXIST);
 402
 403         flags = O_RDWR | O_CLOEXEC;
 404
 405         /* This code is similar to anon_inode_getfd() */
 406         rc = get_unused_fd_flags(flags);
 407         if (rc < 0)
 408                 return ERR_PTR(rc);
 409         fdtmp = rc;
 410
 411         /*
 412          * Patch the file ops.  Needs to be careful that this is rentrant safe.
 413          */
 414         if (fops) {
 415                 PATCH_FOPS(open);
 416                 PATCH_FOPS(poll);
 417                 PATCH_FOPS(read);
 418                 PATCH_FOPS(release);
 419                 PATCH_FOPS(unlocked_ioctl);
 420                 PATCH_FOPS(compat_ioctl);
 421                 PATCH_FOPS(mmap);
 422         } else /* use default ops */
 423                 fops = (struct file_operations *)&afu_fops;
 424
 425         name = kasprintf(GFP_KERNEL, "cxl:%d", ctx->pe);
 426         file = cxl_getfile(name, fops, ctx, flags);
 427         kfree(name);
 428         if (IS_ERR(file))
 429                 goto err_fd;
 430
 431         cxl_context_set_mapping(ctx, file->f_mapping);
 432         *fd = fdtmp;
 433         return file;
 434
 435 err_fd:
 436         put_unused_fd(fdtmp);
 437         return NULL;
 438 }
 439 EXPORT_SYMBOL_GPL(cxl_get_fd);
 440
 441 struct cxl_context *cxl_fops_get_context(struct file *file)
 442 {
 443         return file->private_data;
 444 }
 445 EXPORT_SYMBOL_GPL(cxl_fops_get_context);
 446
 447 void cxl_set_driver_ops(struct cxl_context *ctx,
 448                         struct cxl_afu_driver_ops *ops)
 449 {
 450         WARN_ON(!ops->fetch_event || !ops->event_delivered);
 451         atomic_set(&ctx->afu_driver_events, 0);
 452         ctx->afu_driver_ops = ops;
 453 }
 454 EXPORT_SYMBOL_GPL(cxl_set_driver_ops);
 455
 456 void cxl_context_events_pending(struct cxl_context *ctx,
 457                                 unsigned int new_events)
 458 {
 459         atomic_add(new_events, &ctx->afu_driver_events);
 460         wake_up_all(&ctx->wq);
 461 }
 462 EXPORT_SYMBOL_GPL(cxl_context_events_pending);
 463
 464 int cxl_start_work(struct cxl_context *ctx,
 465                    struct cxl_ioctl_start_work *work)
 466 {
 467         int rc;
 468
 469         /* code taken from afu_ioctl_start_work */
 470         if (!(work->flags & CXL_START_WORK_NUM_IRQS))
 471                 work->num_interrupts = ctx->afu->pp_irqs;
 472         else if ((work->num_interrupts < ctx->afu->pp_irqs) ||
 473                  (work->num_interrupts > ctx->afu->irqs_max)) {
 474                 return -EINVAL;
 475         }
 476
 477         rc = afu_register_irqs(ctx, work->num_interrupts);
 478         if (rc)
 479                 return rc;
 480
 481         rc = cxl_start_context(ctx, work->work_element_descriptor, current);
 482         if (rc < 0) {
 483                 afu_release_irqs(ctx, ctx);
 484                 return rc;
 485         }
 486
 487         return 0;
 488 }
 489 EXPORT_SYMBOL_GPL(cxl_start_work);
 490
 491 void __iomem *cxl_psa_map(struct cxl_context *ctx)
 492 {
 493         if (ctx->status != STARTED)
 494                 return NULL;
 495
 496         pr_devel("%s: psn_phys%llx size:%llx\n",
 497                 __func__, ctx->psn_phys, ctx->psn_size);
 498         return ioremap(ctx->psn_phys, ctx->psn_size);
 499 }
 500 EXPORT_SYMBOL_GPL(cxl_psa_map);
 501
 502 void cxl_psa_unmap(void __iomem *addr)
 503 {
 504         iounmap(addr);
 505 }
 506 EXPORT_SYMBOL_GPL(cxl_psa_unmap);
 507
 508 int cxl_afu_reset(struct cxl_context *ctx)
 509 {
 510         struct cxl_afu *afu = ctx->afu;
 511         int rc;
 512
 513         rc = cxl_ops->afu_reset(afu);
 514         if (rc)
 515                 return rc;
 516
 517         return cxl_ops->afu_check_and_enable(afu);
 518 }
 519 EXPORT_SYMBOL_GPL(cxl_afu_reset);
 520
 521 void cxl_perst_reloads_same_image(struct cxl_afu *afu,
 522                                   bool perst_reloads_same_image)
 523 {
 524         afu->adapter->perst_same_image = perst_reloads_same_image;
 525 }
 526 EXPORT_SYMBOL_GPL(cxl_perst_reloads_same_image);
 527
 528 ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count)
 529 {
 530         struct cxl_afu *afu = cxl_pci_to_afu(dev);
 531         if (IS_ERR(afu))
 532                 return -ENODEV;
 533
 534         return cxl_ops->read_adapter_vpd(afu->adapter, buf, count);
 535 }
 536 EXPORT_SYMBOL_GPL(cxl_read_adapter_vpd);