arch/powerpc/mm/book3s64/iommu

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
mm_iommu_preregistered
mm_iommu_do_alloc
mm_iommu_new
mm_iommu_newdev
mm_iommu_unpin
mm_iommu_do_free
mm_iommu_free
mm_iommu_release
mm_iommu_put
mm_iommu_lookup
mm_iommu_lookup_rm
mm_iommu_get
mm_iommu_ua_to_hpa
mm_iommu_ua_to_hpa_rm
mm_iommu_ua_mark_dirty_rm
mm_iommu_is_devmem
mm_iommu_mapped_inc
mm_iommu_mapped_dec
mm_iommu_init
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  IOMMU helpers in MMU context.
   4  *
   5  *  Copyright (C) 2015 IBM Corp. <aik@ozlabs.ru>
   6  */
   7 
   8 #include <linux/sched/signal.h>
   9 #include <linux/slab.h>
  10 #include <linux/rculist.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/mutex.h>
  13 #include <linux/migrate.h>
  14 #include <linux/hugetlb.h>
  15 #include <linux/swap.h>
  16 #include <linux/sizes.h>
  17 #include <linux/mm.h>
  18 #include <asm/mmu_context.h>
  19 #include <asm/pte-walk.h>
  20 #include <linux/mm_inline.h>
  21 
  22 static DEFINE_MUTEX(mem_list_mutex);
  23 
  24 #define MM_IOMMU_TABLE_GROUP_PAGE_DIRTY 0x1
  25 #define MM_IOMMU_TABLE_GROUP_PAGE_MASK  ~(SZ_4K - 1)
  26 
  27 struct mm_iommu_table_group_mem_t {
  28         struct list_head next;
  29         struct rcu_head rcu;
  30         unsigned long used;
  31         atomic64_t mapped;
  32         unsigned int pageshift;
  33         u64 ua;                 /* userspace address */
  34         u64 entries;            /* number of entries in hpas/hpages[] */
  35         /*
  36          * in mm_iommu_get we temporarily use this to store
  37          * struct page address.
  38          *
  39          * We need to convert ua to hpa in real mode. Make it
  40          * simpler by storing physical address.
  41          */
  42         union {
  43                 struct page **hpages;   /* vmalloc'ed */
  44                 phys_addr_t *hpas;
  45         };
  46 #define MM_IOMMU_TABLE_INVALID_HPA      ((uint64_t)-1)
  47         u64 dev_hpa;            /* Device memory base address */
  48 };
  49 
  50 bool mm_iommu_preregistered(struct mm_struct *mm)
  51 {
  52         return !list_empty(&mm->context.iommu_group_mem_list);
  53 }
  54 EXPORT_SYMBOL_GPL(mm_iommu_preregistered);
  55 
  56 static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua,
  57                               unsigned long entries, unsigned long dev_hpa,
  58                               struct mm_iommu_table_group_mem_t **pmem)
  59 {
  60         struct mm_iommu_table_group_mem_t *mem, *mem2;
  61         long i, ret, locked_entries = 0, pinned = 0;
  62         unsigned int pageshift;
  63         unsigned long entry, chunk;
  64 
  65         if (dev_hpa == MM_IOMMU_TABLE_INVALID_HPA) {
  66                 ret = account_locked_vm(mm, entries, true);
  67                 if (ret)
  68                         return ret;
  69 
  70                 locked_entries = entries;
  71         }
  72 
  73         mem = kzalloc(sizeof(*mem), GFP_KERNEL);
  74         if (!mem) {
  75                 ret = -ENOMEM;
  76                 goto unlock_exit;
  77         }
  78 
  79         if (dev_hpa != MM_IOMMU_TABLE_INVALID_HPA) {
  80                 mem->pageshift = __ffs(dev_hpa | (entries << PAGE_SHIFT));
  81                 mem->dev_hpa = dev_hpa;
  82                 goto good_exit;
  83         }
  84         mem->dev_hpa = MM_IOMMU_TABLE_INVALID_HPA;
  85 
  86         /*
  87          * For a starting point for a maximum page size calculation
  88          * we use @ua and @entries natural alignment to allow IOMMU pages
  89          * smaller than huge pages but still bigger than PAGE_SIZE.
  90          */
  91         mem->pageshift = __ffs(ua | (entries << PAGE_SHIFT));
  92         mem->hpas = vzalloc(array_size(entries, sizeof(mem->hpas[0])));
  93         if (!mem->hpas) {
  94                 kfree(mem);
  95                 ret = -ENOMEM;
  96                 goto unlock_exit;
  97         }
  98 
  99         down_read(&mm->mmap_sem);
 100         chunk = (1UL << (PAGE_SHIFT + MAX_ORDER - 1)) /
 101                         sizeof(struct vm_area_struct *);
 102         chunk = min(chunk, entries);
 103         for (entry = 0; entry < entries; entry += chunk) {
 104                 unsigned long n = min(entries - entry, chunk);
 105 
 106                 ret = get_user_pages(ua + (entry << PAGE_SHIFT), n,
 107                                 FOLL_WRITE | FOLL_LONGTERM,
 108                                 mem->hpages + entry, NULL);
 109                 if (ret == n) {
 110                         pinned += n;
 111                         continue;
 112                 }
 113                 if (ret > 0)
 114                         pinned += ret;
 115                 break;
 116         }
 117         up_read(&mm->mmap_sem);
 118         if (pinned != entries) {
 119                 if (!ret)
 120                         ret = -EFAULT;
 121                 goto free_exit;
 122         }
 123 
 124         pageshift = PAGE_SHIFT;
 125         for (i = 0; i < entries; ++i) {
 126                 struct page *page = mem->hpages[i];
 127 
 128                 /*
 129                  * Allow to use larger than 64k IOMMU pages. Only do that
 130                  * if we are backed by hugetlb.
 131                  */
 132                 if ((mem->pageshift > PAGE_SHIFT) && PageHuge(page))
 133                         pageshift = page_shift(compound_head(page));
 134                 mem->pageshift = min(mem->pageshift, pageshift);
 135                 /*
 136                  * We don't need struct page reference any more, switch
 137                  * to physical address.
 138                  */
 139                 mem->hpas[i] = page_to_pfn(page) << PAGE_SHIFT;
 140         }
 141 
 142 good_exit:
 143         atomic64_set(&mem->mapped, 1);
 144         mem->used = 1;
 145         mem->ua = ua;
 146         mem->entries = entries;
 147 
 148         mutex_lock(&mem_list_mutex);
 149 
 150         list_for_each_entry_rcu(mem2, &mm->context.iommu_group_mem_list, next) {
 151                 /* Overlap? */
 152                 if ((mem2->ua < (ua + (entries << PAGE_SHIFT))) &&
 153                                 (ua < (mem2->ua +
 154                                        (mem2->entries << PAGE_SHIFT)))) {
 155                         ret = -EINVAL;
 156                         mutex_unlock(&mem_list_mutex);
 157                         goto free_exit;
 158                 }
 159         }
 160 
 161         list_add_rcu(&mem->next, &mm->context.iommu_group_mem_list);
 162 
 163         mutex_unlock(&mem_list_mutex);
 164 
 165         *pmem = mem;
 166 
 167         return 0;
 168 
 169 free_exit:
 170         /* free the reference taken */
 171         for (i = 0; i < pinned; i++)
 172                 put_page(mem->hpages[i]);
 173 
 174         vfree(mem->hpas);
 175         kfree(mem);
 176 
 177 unlock_exit:
 178         account_locked_vm(mm, locked_entries, false);
 179 
 180         return ret;
 181 }
 182 
 183 long mm_iommu_new(struct mm_struct *mm, unsigned long ua, unsigned long entries,
 184                 struct mm_iommu_table_group_mem_t **pmem)
 185 {
 186         return mm_iommu_do_alloc(mm, ua, entries, MM_IOMMU_TABLE_INVALID_HPA,
 187                         pmem);
 188 }
 189 EXPORT_SYMBOL_GPL(mm_iommu_new);
 190 
 191 long mm_iommu_newdev(struct mm_struct *mm, unsigned long ua,
 192                 unsigned long entries, unsigned long dev_hpa,
 193                 struct mm_iommu_table_group_mem_t **pmem)
 194 {
 195         return mm_iommu_do_alloc(mm, ua, entries, dev_hpa, pmem);
 196 }
 197 EXPORT_SYMBOL_GPL(mm_iommu_newdev);
 198 
 199 static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem)
 200 {
 201         long i;
 202         struct page *page = NULL;
 203 
 204         if (!mem->hpas)
 205                 return;
 206 
 207         for (i = 0; i < mem->entries; ++i) {
 208                 if (!mem->hpas[i])
 209                         continue;
 210 
 211                 page = pfn_to_page(mem->hpas[i] >> PAGE_SHIFT);
 212                 if (!page)
 213                         continue;
 214 
 215                 if (mem->hpas[i] & MM_IOMMU_TABLE_GROUP_PAGE_DIRTY)
 216                         SetPageDirty(page);
 217 
 218                 put_page(page);
 219                 mem->hpas[i] = 0;
 220         }
 221 }
 222 
 223 static void mm_iommu_do_free(struct mm_iommu_table_group_mem_t *mem)
 224 {
 225 
 226         mm_iommu_unpin(mem);
 227         vfree(mem->hpas);
 228         kfree(mem);
 229 }
 230 
 231 static void mm_iommu_free(struct rcu_head *head)
 232 {
 233         struct mm_iommu_table_group_mem_t *mem = container_of(head,
 234                         struct mm_iommu_table_group_mem_t, rcu);
 235 
 236         mm_iommu_do_free(mem);
 237 }
 238 
 239 static void mm_iommu_release(struct mm_iommu_table_group_mem_t *mem)
 240 {
 241         list_del_rcu(&mem->next);
 242         call_rcu(&mem->rcu, mm_iommu_free);
 243 }
 244 
 245 long mm_iommu_put(struct mm_struct *mm, struct mm_iommu_table_group_mem_t *mem)
 246 {
 247         long ret = 0;
 248         unsigned long unlock_entries = 0;
 249 
 250         mutex_lock(&mem_list_mutex);
 251 
 252         if (mem->used == 0) {
 253                 ret = -ENOENT;
 254                 goto unlock_exit;
 255         }
 256 
 257         --mem->used;
 258         /* There are still users, exit */
 259         if (mem->used)
 260                 goto unlock_exit;
 261 
 262         /* Are there still mappings? */
 263         if (atomic_cmpxchg(&mem->mapped, 1, 0) != 1) {
 264                 ++mem->used;
 265                 ret = -EBUSY;
 266                 goto unlock_exit;
 267         }
 268 
 269         if (mem->dev_hpa == MM_IOMMU_TABLE_INVALID_HPA)
 270                 unlock_entries = mem->entries;
 271 
 272         /* @mapped became 0 so now mappings are disabled, release the region */
 273         mm_iommu_release(mem);
 274 
 275 unlock_exit:
 276         mutex_unlock(&mem_list_mutex);
 277 
 278         account_locked_vm(mm, unlock_entries, false);
 279 
 280         return ret;
 281 }
 282 EXPORT_SYMBOL_GPL(mm_iommu_put);
 283 
 284 struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
 285                 unsigned long ua, unsigned long size)
 286 {
 287         struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
 288 
 289         list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
 290                 if ((mem->ua <= ua) &&
 291                                 (ua + size <= mem->ua +
 292                                  (mem->entries << PAGE_SHIFT))) {
 293                         ret = mem;
 294                         break;
 295                 }
 296         }
 297 
 298         return ret;
 299 }
 300 EXPORT_SYMBOL_GPL(mm_iommu_lookup);
 301 
 302 struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(struct mm_struct *mm,
 303                 unsigned long ua, unsigned long size)
 304 {
 305         struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
 306 
 307         list_for_each_entry_lockless(mem, &mm->context.iommu_group_mem_list,
 308                         next) {
 309                 if ((mem->ua <= ua) &&
 310                                 (ua + size <= mem->ua +
 311                                  (mem->entries << PAGE_SHIFT))) {
 312                         ret = mem;
 313                         break;
 314                 }
 315         }
 316 
 317         return ret;
 318 }
 319 
 320 struct mm_iommu_table_group_mem_t *mm_iommu_get(struct mm_struct *mm,
 321                 unsigned long ua, unsigned long entries)
 322 {
 323         struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
 324 
 325         mutex_lock(&mem_list_mutex);
 326 
 327         list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
 328                 if ((mem->ua == ua) && (mem->entries == entries)) {
 329                         ret = mem;
 330                         ++mem->used;
 331                         break;
 332                 }
 333         }
 334 
 335         mutex_unlock(&mem_list_mutex);
 336 
 337         return ret;
 338 }
 339 EXPORT_SYMBOL_GPL(mm_iommu_get);
 340 
 341 long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
 342                 unsigned long ua, unsigned int pageshift, unsigned long *hpa)
 343 {
 344         const long entry = (ua - mem->ua) >> PAGE_SHIFT;
 345         u64 *va;
 346 
 347         if (entry >= mem->entries)
 348                 return -EFAULT;
 349 
 350         if (pageshift > mem->pageshift)
 351                 return -EFAULT;
 352 
 353         if (!mem->hpas) {
 354                 *hpa = mem->dev_hpa + (ua - mem->ua);
 355                 return 0;
 356         }
 357 
 358         va = &mem->hpas[entry];
 359         *hpa = (*va & MM_IOMMU_TABLE_GROUP_PAGE_MASK) | (ua & ~PAGE_MASK);
 360 
 361         return 0;
 362 }
 363 EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa);
 364 
 365 long mm_iommu_ua_to_hpa_rm(struct mm_iommu_table_group_mem_t *mem,
 366                 unsigned long ua, unsigned int pageshift, unsigned long *hpa)
 367 {
 368         const long entry = (ua - mem->ua) >> PAGE_SHIFT;
 369         unsigned long *pa;
 370 
 371         if (entry >= mem->entries)
 372                 return -EFAULT;
 373 
 374         if (pageshift > mem->pageshift)
 375                 return -EFAULT;
 376 
 377         if (!mem->hpas) {
 378                 *hpa = mem->dev_hpa + (ua - mem->ua);
 379                 return 0;
 380         }
 381 
 382         pa = (void *) vmalloc_to_phys(&mem->hpas[entry]);
 383         if (!pa)
 384                 return -EFAULT;
 385 
 386         *hpa = (*pa & MM_IOMMU_TABLE_GROUP_PAGE_MASK) | (ua & ~PAGE_MASK);
 387 
 388         return 0;
 389 }
 390 
 391 extern void mm_iommu_ua_mark_dirty_rm(struct mm_struct *mm, unsigned long ua)
 392 {
 393         struct mm_iommu_table_group_mem_t *mem;
 394         long entry;
 395         void *va;
 396         unsigned long *pa;
 397 
 398         mem = mm_iommu_lookup_rm(mm, ua, PAGE_SIZE);
 399         if (!mem)
 400                 return;
 401 
 402         if (mem->dev_hpa != MM_IOMMU_TABLE_INVALID_HPA)
 403                 return;
 404 
 405         entry = (ua - mem->ua) >> PAGE_SHIFT;
 406         va = &mem->hpas[entry];
 407 
 408         pa = (void *) vmalloc_to_phys(va);
 409         if (!pa)
 410                 return;
 411 
 412         *pa |= MM_IOMMU_TABLE_GROUP_PAGE_DIRTY;
 413 }
 414 
 415 bool mm_iommu_is_devmem(struct mm_struct *mm, unsigned long hpa,
 416                 unsigned int pageshift, unsigned long *size)
 417 {
 418         struct mm_iommu_table_group_mem_t *mem;
 419         unsigned long end;
 420 
 421         list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
 422                 if (mem->dev_hpa == MM_IOMMU_TABLE_INVALID_HPA)
 423                         continue;
 424 
 425                 end = mem->dev_hpa + (mem->entries << PAGE_SHIFT);
 426                 if ((mem->dev_hpa <= hpa) && (hpa < end)) {
 427                         /*
 428                          * Since the IOMMU page size might be bigger than
 429                          * PAGE_SIZE, the amount of preregistered memory
 430                          * starting from @hpa might be smaller than 1<<pageshift
 431                          * and the caller needs to distinguish this situation.
 432                          */
 433                         *size = min(1UL << pageshift, end - hpa);
 434                         return true;
 435                 }
 436         }
 437 
 438         return false;
 439 }
 440 EXPORT_SYMBOL_GPL(mm_iommu_is_devmem);
 441 
 442 long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem)
 443 {
 444         if (atomic64_inc_not_zero(&mem->mapped))
 445                 return 0;
 446 
 447         /* Last mm_iommu_put() has been called, no more mappings allowed() */
 448         return -ENXIO;
 449 }
 450 EXPORT_SYMBOL_GPL(mm_iommu_mapped_inc);
 451 
 452 void mm_iommu_mapped_dec(struct mm_iommu_table_group_mem_t *mem)
 453 {
 454         atomic64_add_unless(&mem->mapped, -1, 1);
 455 }
 456 EXPORT_SYMBOL_GPL(mm_iommu_mapped_dec);
 457 
 458 void mm_iommu_init(struct mm_struct *mm)
 459 {
 460         INIT_LIST_HEAD_RCU(&mm->context.iommu_group_mem_list);
 461 }
/* [<][>][^][v][top][bottom][index][help] */
root/arch/powerpc/mm/book3s64/iommu_api.c

DEFINITIONS
