drivers/misc/cxl/api.c

   1 /*
   2  * Copyright 2014 IBM Corp.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9
  10 #include <linux/pci.h>
  11 #include <linux/slab.h>
  12 #include <linux/file.h>
  13 #include <misc/cxl.h>
  14 #include <linux/module.h>
  15 #include <linux/mount.h>
  16 #include <linux/sched/mm.h>
  17 #include <linux/mmu_context.h>
  18
  19 #include "cxl.h"
  20
  21 /*
  22  * Since we want to track memory mappings to be able to force-unmap
  23  * when the AFU is no longer reachable, we need an inode. For devices
  24  * opened through the cxl user API, this is not a problem, but a
  25  * userland process can also get a cxl fd through the cxl_get_fd()
  26  * API, which is used by the cxlflash driver.
  27  *
  28  * Therefore we implement our own simple pseudo-filesystem and inode
  29  * allocator. We don't use the anonymous inode, as we need the
  30  * meta-data associated with it (address_space) and it is shared by
  31  * other drivers/processes, so it could lead to cxl unmapping VMAs
  32  * from random processes.
  33  */
  34
  35 #define CXL_PSEUDO_FS_MAGIC     0x1697697f
  36
  37 static int cxl_fs_cnt;
  38 static struct vfsmount *cxl_vfs_mount;
  39
  40 static const struct dentry_operations cxl_fs_dops = {
  41         .d_dname        = simple_dname,
  42 };
  43
  44 static struct dentry *cxl_fs_mount(struct file_system_type *fs_type, int flags,
  45                                 const char *dev_name, void *data)
  46 {
  47         return mount_pseudo(fs_type, "cxl:", NULL, &cxl_fs_dops,
  48                         CXL_PSEUDO_FS_MAGIC);
  49 }
  50
  51 static struct file_system_type cxl_fs_type = {
  52         .name           = "cxl",
  53         .owner          = THIS_MODULE,
  54         .mount          = cxl_fs_mount,
  55         .kill_sb        = kill_anon_super,
  56 };
  57
  58
  59 void cxl_release_mapping(struct cxl_context *ctx)
  60 {
  61         if (ctx->kernelapi && ctx->mapping)
  62                 simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
  63 }
  64
  65 static struct file *cxl_getfile(const char *name,
  66                                 const struct file_operations *fops,
  67                                 void *priv, int flags)
  68 {
  69         struct file *file;
  70         struct inode *inode;
  71         int rc;
  72
  73         /* strongly inspired by anon_inode_getfile() */
  74
  75         if (fops->owner && !try_module_get(fops->owner))
  76                 return ERR_PTR(-ENOENT);
  77
  78         rc = simple_pin_fs(&cxl_fs_type, &cxl_vfs_mount, &cxl_fs_cnt);
  79         if (rc < 0) {
  80                 pr_err("Cannot mount cxl pseudo filesystem: %d\n", rc);
  81                 file = ERR_PTR(rc);
  82                 goto err_module;
  83         }
  84
  85         inode = alloc_anon_inode(cxl_vfs_mount->mnt_sb);
  86         if (IS_ERR(inode)) {
  87                 file = ERR_CAST(inode);
  88                 goto err_fs;
  89         }
  90
  91         file = alloc_file_pseudo(inode, cxl_vfs_mount, name,
  92                                  flags & (O_ACCMODE | O_NONBLOCK), fops);
  93         if (IS_ERR(file))
  94                 goto err_inode;
  95
  96         file->private_data = priv;
  97
  98         return file;
  99
 100 err_inode:
 101         iput(inode);
 102 err_fs:
 103         simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
 104 err_module:
 105         module_put(fops->owner);
 106         return file;
 107 }
 108
 109 struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
 110 {
 111         struct cxl_afu *afu;
 112         struct cxl_context  *ctx;
 113         int rc;
 114
 115         afu = cxl_pci_to_afu(dev);
 116         if (IS_ERR(afu))
 117                 return ERR_CAST(afu);
 118
 119         ctx = cxl_context_alloc();
 120         if (!ctx)
 121                 return ERR_PTR(-ENOMEM);
 122
 123         ctx->kernelapi = true;
 124
 125         /* Make it a slave context.  We can promote it later? */
 126         rc = cxl_context_init(ctx, afu, false);
 127         if (rc)
 128                 goto err_ctx;
 129
 130         return ctx;
 131
 132 err_ctx:
 133         kfree(ctx);
 134         return ERR_PTR(rc);
 135 }
 136 EXPORT_SYMBOL_GPL(cxl_dev_context_init);
 137
 138 struct cxl_context *cxl_get_context(struct pci_dev *dev)
 139 {
 140         return dev->dev.archdata.cxl_ctx;
 141 }
 142 EXPORT_SYMBOL_GPL(cxl_get_context);
 143
 144 int cxl_release_context(struct cxl_context *ctx)
 145 {
 146         if (ctx->status >= STARTED)
 147                 return -EBUSY;
 148
 149         cxl_context_free(ctx);
 150
 151         return 0;
 152 }
 153 EXPORT_SYMBOL_GPL(cxl_release_context);
 154
 155 static irq_hw_number_t cxl_find_afu_irq(struct cxl_context *ctx, int num)
 156 {
 157         __u16 range;
 158         int r;
 159
 160         for (r = 0; r < CXL_IRQ_RANGES; r++) {
 161                 range = ctx->irqs.range[r];
 162                 if (num < range) {
 163                         return ctx->irqs.offset[r] + num;
 164                 }
 165                 num -= range;
 166         }
 167         return 0;
 168 }
 169
 170
 171 int cxl_set_priv(struct cxl_context *ctx, void *priv)
 172 {
 173         if (!ctx)
 174                 return -EINVAL;
 175
 176         ctx->priv = priv;
 177
 178         return 0;
 179 }
 180 EXPORT_SYMBOL_GPL(cxl_set_priv);
 181
 182 void *cxl_get_priv(struct cxl_context *ctx)
 183 {
 184         if (!ctx)
 185                 return ERR_PTR(-EINVAL);
 186
 187         return ctx->priv;
 188 }
 189 EXPORT_SYMBOL_GPL(cxl_get_priv);
 190
 191 int cxl_allocate_afu_irqs(struct cxl_context *ctx, int num)
 192 {
 193         int res;
 194         irq_hw_number_t hwirq;
 195
 196         if (num == 0)
 197                 num = ctx->afu->pp_irqs;
 198         res = afu_allocate_irqs(ctx, num);
 199         if (res)
 200                 return res;
 201
 202         if (!cpu_has_feature(CPU_FTR_HVMODE)) {
 203                 /* In a guest, the PSL interrupt is not multiplexed. It was
 204                  * allocated above, and we need to set its handler
 205                  */
 206                 hwirq = cxl_find_afu_irq(ctx, 0);
 207                 if (hwirq)
 208                         cxl_map_irq(ctx->afu->adapter, hwirq, cxl_ops->psl_interrupt, ctx, "psl");
 209         }
 210
 211         if (ctx->status == STARTED) {
 212                 if (cxl_ops->update_ivtes)
 213                         cxl_ops->update_ivtes(ctx);
 214                 else WARN(1, "BUG: cxl_allocate_afu_irqs must be called prior to starting the context on this platform\n");
 215         }
 216
 217         return res;
 218 }
 219 EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
 220
 221 void cxl_free_afu_irqs(struct cxl_context *ctx)
 222 {
 223         irq_hw_number_t hwirq;
 224         unsigned int virq;
 225
 226         if (!cpu_has_feature(CPU_FTR_HVMODE)) {
 227                 hwirq = cxl_find_afu_irq(ctx, 0);
 228                 if (hwirq) {
 229                         virq = irq_find_mapping(NULL, hwirq);
 230                         if (virq)
 231                                 cxl_unmap_irq(virq, ctx);
 232                 }
 233         }
 234         afu_irq_name_free(ctx);
 235         cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
 236 }
 237 EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
 238
 239 int cxl_map_afu_irq(struct cxl_context *ctx, int num,
 240                     irq_handler_t handler, void *cookie, char *name)
 241 {
 242         irq_hw_number_t hwirq;
 243
 244         /*
 245          * Find interrupt we are to register.
 246          */
 247         hwirq = cxl_find_afu_irq(ctx, num);
 248         if (!hwirq)
 249                 return -ENOENT;
 250
 251         return cxl_map_irq(ctx->afu->adapter, hwirq, handler, cookie, name);
 252 }
 253 EXPORT_SYMBOL_GPL(cxl_map_afu_irq);
 254
 255 void cxl_unmap_afu_irq(struct cxl_context *ctx, int num, void *cookie)
 256 {
 257         irq_hw_number_t hwirq;
 258         unsigned int virq;
 259
 260         hwirq = cxl_find_afu_irq(ctx, num);
 261         if (!hwirq)
 262                 return;
 263
 264         virq = irq_find_mapping(NULL, hwirq);
 265         if (virq)
 266                 cxl_unmap_irq(virq, cookie);
 267 }
 268 EXPORT_SYMBOL_GPL(cxl_unmap_afu_irq);
 269
 270 /*
 271  * Start a context
 272  * Code here similar to afu_ioctl_start_work().
 273  */
 274 int cxl_start_context(struct cxl_context *ctx, u64 wed,
 275                       struct task_struct *task)
 276 {
 277         int rc = 0;
 278         bool kernel = true;
 279
 280         pr_devel("%s: pe: %i\n", __func__, ctx->pe);
 281
 282         mutex_lock(&ctx->status_mutex);
 283         if (ctx->status == STARTED)
 284                 goto out; /* already started */
 285
 286         /*
 287          * Increment the mapped context count for adapter. This also checks
 288          * if adapter_context_lock is taken.
 289          */
 290         rc = cxl_adapter_context_get(ctx->afu->adapter);
 291         if (rc)
 292                 goto out;
 293
 294         if (task) {
 295                 ctx->pid = get_task_pid(task, PIDTYPE_PID);
 296                 kernel = false;
 297
 298                 /* acquire a reference to the task's mm */
 299                 ctx->mm = get_task_mm(current);
 300
 301                 /* ensure this mm_struct can't be freed */
 302                 cxl_context_mm_count_get(ctx);
 303
 304                 if (ctx->mm) {
 305                         /* decrement the use count from above */
 306                         mmput(ctx->mm);
 307                         /* make TLBIs for this context global */
 308                         mm_context_add_copro(ctx->mm);
 309                 }
 310         }
 311
 312         /*
 313          * Increment driver use count. Enables global TLBIs for hash
 314          * and callbacks to handle the segment table
 315          */
 316         cxl_ctx_get();
 317
 318         /* See the comment in afu_ioctl_start_work() */
 319         smp_mb();
 320
 321         if ((rc = cxl_ops->attach_process(ctx, kernel, wed, 0))) {
 322                 put_pid(ctx->pid);
 323                 ctx->pid = NULL;
 324                 cxl_adapter_context_put(ctx->afu->adapter);
 325                 cxl_ctx_put();
 326                 if (task) {
 327                         cxl_context_mm_count_put(ctx);
 328                         if (ctx->mm)
 329                                 mm_context_remove_copro(ctx->mm);
 330                 }
 331                 goto out;
 332         }
 333
 334         ctx->status = STARTED;
 335 out:
 336         mutex_unlock(&ctx->status_mutex);
 337         return rc;
 338 }
 339 EXPORT_SYMBOL_GPL(cxl_start_context);
 340
 341 int cxl_process_element(struct cxl_context *ctx)
 342 {
 343         return ctx->external_pe;
 344 }
 345 EXPORT_SYMBOL_GPL(cxl_process_element);
 346
 347 /* Stop a context.  Returns 0 on success, otherwise -Errno */
 348 int cxl_stop_context(struct cxl_context *ctx)
 349 {
 350         return __detach_context(ctx);
 351 }
 352 EXPORT_SYMBOL_GPL(cxl_stop_context);
 353
 354 void cxl_set_master(struct cxl_context *ctx)
 355 {
 356         ctx->master = true;
 357 }
 358 EXPORT_SYMBOL_GPL(cxl_set_master);
 359
 360 /* wrappers around afu_* file ops which are EXPORTED */
 361 int cxl_fd_open(struct inode *inode, struct file *file)
 362 {
 363         return afu_open(inode, file);
 364 }
 365 EXPORT_SYMBOL_GPL(cxl_fd_open);
 366 int cxl_fd_release(struct inode *inode, struct file *file)
 367 {
 368         return afu_release(inode, file);
 369 }
 370 EXPORT_SYMBOL_GPL(cxl_fd_release);
 371 long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 372 {
 373         return afu_ioctl(file, cmd, arg);
 374 }
 375 EXPORT_SYMBOL_GPL(cxl_fd_ioctl);
 376 int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm)
 377 {
 378         return afu_mmap(file, vm);
 379 }
 380 EXPORT_SYMBOL_GPL(cxl_fd_mmap);
 381 __poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll)
 382 {
 383         return afu_poll(file, poll);
 384 }
 385 EXPORT_SYMBOL_GPL(cxl_fd_poll);
 386 ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
 387                         loff_t *off)
 388 {
 389         return afu_read(file, buf, count, off);
 390 }
 391 EXPORT_SYMBOL_GPL(cxl_fd_read);
 392
 393 #define PATCH_FOPS(NAME) if (!fops->NAME) fops->NAME = afu_fops.NAME
 394
 395 /* Get a struct file and fd for a context and attach the ops */
 396 struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
 397                         int *fd)
 398 {
 399         struct file *file;
 400         int rc, flags, fdtmp;
 401         char *name = NULL;
 402
 403         /* only allow one per context */
 404         if (ctx->mapping)
 405                 return ERR_PTR(-EEXIST);
 406
 407         flags = O_RDWR | O_CLOEXEC;
 408
 409         /* This code is similar to anon_inode_getfd() */
 410         rc = get_unused_fd_flags(flags);
 411         if (rc < 0)
 412                 return ERR_PTR(rc);
 413         fdtmp = rc;
 414
 415         /*
 416          * Patch the file ops.  Needs to be careful that this is rentrant safe.
 417          */
 418         if (fops) {
 419                 PATCH_FOPS(open);
 420                 PATCH_FOPS(poll);
 421                 PATCH_FOPS(read);
 422                 PATCH_FOPS(release);
 423                 PATCH_FOPS(unlocked_ioctl);
 424                 PATCH_FOPS(compat_ioctl);
 425                 PATCH_FOPS(mmap);
 426         } else /* use default ops */
 427                 fops = (struct file_operations *)&afu_fops;
 428
 429         name = kasprintf(GFP_KERNEL, "cxl:%d", ctx->pe);
 430         file = cxl_getfile(name, fops, ctx, flags);
 431         kfree(name);
 432         if (IS_ERR(file))
 433                 goto err_fd;
 434
 435         cxl_context_set_mapping(ctx, file->f_mapping);
 436         *fd = fdtmp;
 437         return file;
 438
 439 err_fd:
 440         put_unused_fd(fdtmp);
 441         return NULL;
 442 }
 443 EXPORT_SYMBOL_GPL(cxl_get_fd);
 444
 445 struct cxl_context *cxl_fops_get_context(struct file *file)
 446 {
 447         return file->private_data;
 448 }
 449 EXPORT_SYMBOL_GPL(cxl_fops_get_context);
 450
 451 void cxl_set_driver_ops(struct cxl_context *ctx,
 452                         struct cxl_afu_driver_ops *ops)
 453 {
 454         WARN_ON(!ops->fetch_event || !ops->event_delivered);
 455         atomic_set(&ctx->afu_driver_events, 0);
 456         ctx->afu_driver_ops = ops;
 457 }
 458 EXPORT_SYMBOL_GPL(cxl_set_driver_ops);
 459
 460 void cxl_context_events_pending(struct cxl_context *ctx,
 461                                 unsigned int new_events)
 462 {
 463         atomic_add(new_events, &ctx->afu_driver_events);
 464         wake_up_all(&ctx->wq);
 465 }
 466 EXPORT_SYMBOL_GPL(cxl_context_events_pending);
 467
 468 int cxl_start_work(struct cxl_context *ctx,
 469                    struct cxl_ioctl_start_work *work)
 470 {
 471         int rc;
 472
 473         /* code taken from afu_ioctl_start_work */
 474         if (!(work->flags & CXL_START_WORK_NUM_IRQS))
 475                 work->num_interrupts = ctx->afu->pp_irqs;
 476         else if ((work->num_interrupts < ctx->afu->pp_irqs) ||
 477                  (work->num_interrupts > ctx->afu->irqs_max)) {
 478                 return -EINVAL;
 479         }
 480
 481         rc = afu_register_irqs(ctx, work->num_interrupts);
 482         if (rc)
 483                 return rc;
 484
 485         rc = cxl_start_context(ctx, work->work_element_descriptor, current);
 486         if (rc < 0) {
 487                 afu_release_irqs(ctx, ctx);
 488                 return rc;
 489         }
 490
 491         return 0;
 492 }
 493 EXPORT_SYMBOL_GPL(cxl_start_work);
 494
 495 void __iomem *cxl_psa_map(struct cxl_context *ctx)
 496 {
 497         if (ctx->status != STARTED)
 498                 return NULL;
 499
 500         pr_devel("%s: psn_phys%llx size:%llx\n",
 501                 __func__, ctx->psn_phys, ctx->psn_size);
 502         return ioremap(ctx->psn_phys, ctx->psn_size);
 503 }
 504 EXPORT_SYMBOL_GPL(cxl_psa_map);
 505
 506 void cxl_psa_unmap(void __iomem *addr)
 507 {
 508         iounmap(addr);
 509 }
 510 EXPORT_SYMBOL_GPL(cxl_psa_unmap);
 511
 512 int cxl_afu_reset(struct cxl_context *ctx)
 513 {
 514         struct cxl_afu *afu = ctx->afu;
 515         int rc;
 516
 517         rc = cxl_ops->afu_reset(afu);
 518         if (rc)
 519                 return rc;
 520
 521         return cxl_ops->afu_check_and_enable(afu);
 522 }
 523 EXPORT_SYMBOL_GPL(cxl_afu_reset);
 524
 525 void cxl_perst_reloads_same_image(struct cxl_afu *afu,
 526                                   bool perst_reloads_same_image)
 527 {
 528         afu->adapter->perst_same_image = perst_reloads_same_image;
 529 }
 530 EXPORT_SYMBOL_GPL(cxl_perst_reloads_same_image);
 531
 532 ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count)
 533 {
 534         struct cxl_afu *afu = cxl_pci_to_afu(dev);
 535         if (IS_ERR(afu))
 536                 return -ENODEV;
 537
 538         return cxl_ops->read_adapter_vpd(afu->adapter, buf, count);
 539 }
 540 EXPORT_SYMBOL_GPL(cxl_read_adapter_vpd);