linux-core/drm_compat.c

   1 /**************************************************************************
   2  *
   3  * This kernel module is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU General Public License as
   5  * published by the Free Software Foundation; either version 2 of the
   6  * License, or (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  16  *
  17  **************************************************************************/
  18 /*
  19  * This code provides access to unexported mm kernel features. It is necessary
  20  * to use the new DRM memory manager code with kernels that don't support it
  21  * directly.
  22  *
  23  * Authors: Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
  24  *          Linux kernel mm subsystem authors.
  25  *          (Most code taken from there).
  26  */
  27
  28 #include "drmP.h"
  29
  30 #if defined(CONFIG_X86) && (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15))
  31
  32 /*
  33  * These have bad performance in the AGP module for the indicated kernel versions.
  34  */
  35
  36 int drm_map_page_into_agp(struct page *page)
  37 {
  38         int i;
  39         i = change_page_attr(page, 1, PAGE_KERNEL_NOCACHE);
  40         /* Caller's responsibility to call global_flush_tlb() for
  41          * performance reasons */
  42         return i;
  43 }
  44
  45 int drm_unmap_page_from_agp(struct page *page)
  46 {
  47         int i;
  48         i = change_page_attr(page, 1, PAGE_KERNEL);
  49         /* Caller's responsibility to call global_flush_tlb() for
  50          * performance reasons */
  51         return i;
  52 }
  53 #endif
  54
  55
  56 #if  (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19))
  57
  58 /*
  59  * The protection map was exported in 2.6.19
  60  */
  61
  62 pgprot_t vm_get_page_prot(unsigned long vm_flags)
  63 {
  64 #ifdef MODULE
  65         static pgprot_t drm_protection_map[16] = {
  66                 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
  67                 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
  68         };
  69
  70         return drm_protection_map[vm_flags & 0x0F];
  71 #else
  72         extern pgprot_t protection_map[];
  73         return protection_map[vm_flags & 0x0F];
  74 #endif
  75 };
  76 #endif
  77
  78
  79 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15))
  80
  81 /*
  82  * vm code for kernels below 2.6.15 in which version a major vm write
  83  * occured. This implement a simple straightforward
  84  * version similar to what's going to be
  85  * in kernel 2.6.19+
  86  * Kernels below 2.6.15 use nopage whereas 2.6.19 and upwards use
  87  * nopfn.
  88  */
  89
  90 static struct {
  91         spinlock_t lock;
  92         struct page *dummy_page;
  93         atomic_t present;
  94 } drm_np_retry =
  95 {SPIN_LOCK_UNLOCKED, NOPAGE_OOM, ATOMIC_INIT(0)};
  96
  97 struct page * get_nopage_retry(void)
  98 {
  99         if (atomic_read(&drm_np_retry.present) == 0) {
 100                 struct page *page = alloc_page(GFP_KERNEL);
 101                 if (!page)
 102                         return NOPAGE_OOM;
 103                 spin_lock(&drm_np_retry.lock);
 104                 drm_np_retry.dummy_page = page;
 105                 atomic_set(&drm_np_retry.present,1);
 106                 spin_unlock(&drm_np_retry.lock);
 107         }
 108         get_page(drm_np_retry.dummy_page);
 109         return drm_np_retry.dummy_page;
 110 }
 111
 112 void free_nopage_retry(void)
 113 {
 114         if (atomic_read(&drm_np_retry.present) == 1) {
 115                 spin_lock(&drm_np_retry.lock);
 116                 __free_page(drm_np_retry.dummy_page);
 117                 drm_np_retry.dummy_page = NULL;
 118                 atomic_set(&drm_np_retry.present, 0);
 119                 spin_unlock(&drm_np_retry.lock);
 120         }
 121 }
 122
 123 struct page *drm_bo_vm_nopage(struct vm_area_struct *vma,
 124                                unsigned long address,
 125                                int *type)
 126 {
 127         struct fault_data data;
 128
 129         if (type)
 130                 *type = VM_FAULT_MINOR;
 131
 132         data.address = address;
 133         data.vma = vma;
 134         drm_bo_vm_fault(vma, &data);
 135         switch (data.type) {
 136         case VM_FAULT_OOM:
 137                 return NOPAGE_OOM;
 138         case VM_FAULT_SIGBUS:
 139                 return NOPAGE_SIGBUS;
 140         default:
 141                 break;
 142         }
 143
 144         return NOPAGE_REFAULT;
 145 }
 146
 147 #endif
 148
 149 #if !defined(DRM_FULL_MM_COMPAT) && \
 150   ((LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15)) || \
 151    (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19)))
 152
 153 static int drm_pte_is_clear(struct vm_area_struct *vma,
 154                             unsigned long addr)
 155 {
 156         struct mm_struct *mm = vma->vm_mm;
 157         int ret = 1;
 158         pte_t *pte;
 159         pmd_t *pmd;
 160         pud_t *pud;
 161         pgd_t *pgd;
 162
 163         spin_lock(&mm->page_table_lock);
 164         pgd = pgd_offset(mm, addr);
 165         if (pgd_none(*pgd))
 166                 goto unlock;
 167         pud = pud_offset(pgd, addr);
 168         if (pud_none(*pud))
 169                 goto unlock;
 170         pmd = pmd_offset(pud, addr);
 171         if (pmd_none(*pmd))
 172                 goto unlock;
 173         pte = pte_offset_map(pmd, addr);
 174         if (!pte)
 175                 goto unlock;
 176         ret = pte_none(*pte);
 177         pte_unmap(pte);
 178  unlock:
 179         spin_unlock(&mm->page_table_lock);
 180         return ret;
 181 }
 182
 183 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
 184                   unsigned long pfn)
 185 {
 186         int ret;
 187         if (!drm_pte_is_clear(vma, addr))
 188                 return -EBUSY;
 189
 190         ret = io_remap_pfn_range(vma, addr, pfn, PAGE_SIZE, vma->vm_page_prot);
 191         return ret;
 192 }
 193 #endif
 194
 195 #if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,19) && !defined(DRM_FULL_MM_COMPAT))
 196
 197 /**
 198  * While waiting for the fault() handler to appear in
 199  * we accomplish approximately
 200  * the same wrapping it with nopfn.
 201  */
 202
 203 unsigned long drm_bo_vm_nopfn(struct vm_area_struct * vma,
 204                            unsigned long address)
 205 {
 206         struct fault_data data;
 207         data.address = address;
 208
 209         (void) drm_bo_vm_fault(vma, &data);
 210         if (data.type == VM_FAULT_OOM)
 211                 return NOPFN_OOM;
 212         else if (data.type == VM_FAULT_SIGBUS)
 213                 return NOPFN_SIGBUS;
 214
 215         /*
 216          * pfn already set.
 217          */
 218
 219         return 0;
 220 }
 221 #endif
 222
 223
 224 #ifdef DRM_ODD_MM_COMPAT
 225
 226 /*
 227  * VM compatibility code for 2.6.15-2.6.18. This code implements a complicated
 228  * workaround for a single BUG statement in do_no_page in these versions. The
 229  * tricky thing is that we need to take the mmap_sem in exclusive mode for _all_
 230  * vmas mapping the ttm, before dev->struct_mutex is taken. The way we do this is to
 231  * check first take the dev->struct_mutex, and then trylock all mmap_sems. If this
 232  * fails for a single mmap_sem, we have to release all sems and the dev->struct_mutex,
 233  * release the cpu and retry. We also need to keep track of all vmas mapping the ttm.
 234  * phew.
 235  */
 236
 237 typedef struct p_mm_entry {
 238         struct list_head head;
 239         struct mm_struct *mm;
 240         atomic_t refcount;
 241         int locked;
 242 } p_mm_entry_t;
 243
 244 typedef struct vma_entry {
 245         struct list_head head;
 246         struct vm_area_struct *vma;
 247 } vma_entry_t;
 248
 249
 250 struct page *drm_bo_vm_nopage(struct vm_area_struct *vma,
 251                                unsigned long address,
 252                                int *type)
 253 {
 254         drm_buffer_object_t *bo = (drm_buffer_object_t *) vma->vm_private_data;
 255         unsigned long page_offset;
 256         struct page *page;
 257         drm_ttm_t *ttm;
 258         drm_device_t *dev;
 259
 260         mutex_lock(&bo->mutex);
 261
 262         if (type)
 263                 *type = VM_FAULT_MINOR;
 264
 265         if (address > vma->vm_end) {
 266                 page = NOPAGE_SIGBUS;
 267                 goto out_unlock;
 268         }
 269
 270         dev = bo->dev;
 271
 272         if (drm_mem_reg_is_pci(dev, &bo->mem)) {
 273                 DRM_ERROR("Invalid compat nopage.\n");
 274                 page = NOPAGE_SIGBUS;
 275                 goto out_unlock;
 276         }
 277
 278         ttm = bo->ttm;
 279         drm_ttm_fixup_caching(ttm);
 280         page_offset = (address - vma->vm_start) >> PAGE_SHIFT;
 281         page = drm_ttm_get_page(ttm, page_offset);
 282         if (!page) {
 283                 page = NOPAGE_OOM;
 284                 goto out_unlock;
 285         }
 286
 287         get_page(page);
 288 out_unlock:
 289         mutex_unlock(&bo->mutex);
 290         return page;
 291 }
 292
 293
 294
 295
 296 int drm_bo_map_bound(struct vm_area_struct *vma)
 297 {
 298         drm_buffer_object_t *bo = (drm_buffer_object_t *)vma->vm_private_data;
 299         int ret = 0;
 300         unsigned long bus_base;
 301         unsigned long bus_offset;
 302         unsigned long bus_size;
 303
 304         ret = drm_bo_pci_offset(bo->dev, &bo->mem, &bus_base,
 305                                 &bus_offset, &bus_size);
 306         BUG_ON(ret);
 307
 308         if (bus_size) {
 309                 unsigned long pfn = (bus_base + bus_offset) >> PAGE_SHIFT;
 310                 pgprot_t pgprot = drm_io_prot(_DRM_AGP, vma);
 311                 ret = io_remap_pfn_range(vma, vma->vm_start, pfn,
 312                                          vma->vm_end - vma->vm_start,
 313                                          pgprot);
 314         }
 315
 316         return ret;
 317 }
 318
 319
 320 int drm_bo_add_vma(drm_buffer_object_t * bo, struct vm_area_struct *vma)
 321 {
 322         p_mm_entry_t *entry, *n_entry;
 323         vma_entry_t *v_entry;
 324         struct mm_struct *mm = vma->vm_mm;
 325
 326         v_entry = drm_ctl_alloc(sizeof(*v_entry), DRM_MEM_BUFOBJ);
 327         if (!v_entry) {
 328                 DRM_ERROR("Allocation of vma pointer entry failed\n");
 329                 return -ENOMEM;
 330         }
 331         v_entry->vma = vma;
 332
 333         list_add_tail(&v_entry->head, &bo->vma_list);
 334
 335         list_for_each_entry(entry, &bo->p_mm_list, head) {
 336                 if (mm == entry->mm) {
 337                         atomic_inc(&entry->refcount);
 338                         return 0;
 339                 } else if ((unsigned long)mm < (unsigned long)entry->mm) ;
 340         }
 341
 342         n_entry = drm_ctl_alloc(sizeof(*n_entry), DRM_MEM_BUFOBJ);
 343         if (!n_entry) {
 344                 DRM_ERROR("Allocation of process mm pointer entry failed\n");
 345                 return -ENOMEM;
 346         }
 347         INIT_LIST_HEAD(&n_entry->head);
 348         n_entry->mm = mm;
 349         n_entry->locked = 0;
 350         atomic_set(&n_entry->refcount, 0);
 351         list_add_tail(&n_entry->head, &entry->head);
 352
 353         return 0;
 354 }
 355
 356 void drm_bo_delete_vma(drm_buffer_object_t * bo, struct vm_area_struct *vma)
 357 {
 358         p_mm_entry_t *entry, *n;
 359         vma_entry_t *v_entry, *v_n;
 360         int found = 0;
 361         struct mm_struct *mm = vma->vm_mm;
 362
 363         list_for_each_entry_safe(v_entry, v_n, &bo->vma_list, head) {
 364                 if (v_entry->vma == vma) {
 365                         found = 1;
 366                         list_del(&v_entry->head);
 367                         drm_ctl_free(v_entry, sizeof(*v_entry), DRM_MEM_BUFOBJ);
 368                         break;
 369                 }
 370         }
 371         BUG_ON(!found);
 372
 373         list_for_each_entry_safe(entry, n, &bo->p_mm_list, head) {
 374                 if (mm == entry->mm) {
 375                         if (atomic_add_negative(-1, &entry->refcount)) {
 376                                 list_del(&entry->head);
 377                                 BUG_ON(entry->locked);
 378                                 drm_ctl_free(entry, sizeof(*entry), DRM_MEM_BUFOBJ);
 379                         }
 380                         return;
 381                 }
 382         }
 383         BUG_ON(1);
 384 }
 385
 386
 387
 388 int drm_bo_lock_kmm(drm_buffer_object_t * bo)
 389 {
 390         p_mm_entry_t *entry;
 391         int lock_ok = 1;
 392
 393         list_for_each_entry(entry, &bo->p_mm_list, head) {
 394                 BUG_ON(entry->locked);
 395                 if (!down_write_trylock(&entry->mm->mmap_sem)) {
 396                         lock_ok = 0;
 397                         break;
 398                 }
 399                 entry->locked = 1;
 400         }
 401
 402         if (lock_ok)
 403                 return 0;
 404
 405         list_for_each_entry(entry, &bo->p_mm_list, head) {
 406                 if (!entry->locked)
 407                         break;
 408                 up_write(&entry->mm->mmap_sem);
 409                 entry->locked = 0;
 410         }
 411
 412         /*
 413          * Possible deadlock. Try again. Our callers should handle this
 414          * and restart.
 415          */
 416
 417         return -EAGAIN;
 418 }
 419
 420 void drm_bo_unlock_kmm(drm_buffer_object_t * bo)
 421 {
 422         p_mm_entry_t *entry;
 423
 424         list_for_each_entry(entry, &bo->p_mm_list, head) {
 425                 BUG_ON(!entry->locked);
 426                 up_write(&entry->mm->mmap_sem);
 427                 entry->locked = 0;
 428         }
 429 }
 430
 431 int drm_bo_remap_bound(drm_buffer_object_t *bo)
 432 {
 433         vma_entry_t *v_entry;
 434         int ret = 0;
 435
 436         if (drm_mem_reg_is_pci(bo->dev, &bo->mem)) {
 437                 list_for_each_entry(v_entry, &bo->vma_list, head) {
 438                         ret = drm_bo_map_bound(v_entry->vma);
 439                         if (ret)
 440                                 break;
 441                 }
 442         }
 443
 444         return ret;
 445 }
 446
 447 void drm_bo_finish_unmap(drm_buffer_object_t *bo)
 448 {
 449         vma_entry_t *v_entry;
 450
 451         list_for_each_entry(v_entry, &bo->vma_list, head) {
 452                 v_entry->vma->vm_flags &= ~VM_PFNMAP;
 453         }
 454 }
 455
 456 #endif
 457