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 2.6.20+?
  86  */
  87
  88 static int drm_pte_is_clear(struct vm_area_struct *vma,
  89                             unsigned long addr)
  90 {
  91         struct mm_struct *mm = vma->vm_mm;
  92         int ret = 1;
  93         pte_t *pte;
  94         pmd_t *pmd;
  95         pud_t *pud;
  96         pgd_t *pgd;
  97
  98
  99         spin_lock(&mm->page_table_lock);
 100         pgd = pgd_offset(mm, addr);
 101         if (pgd_none(*pgd))
 102                 goto unlock;
 103         pud = pud_offset(pgd, addr);
 104         if (pud_none(*pud))
 105                 goto unlock;
 106         pmd = pmd_offset(pud, addr);
 107         if (pmd_none(*pmd))
 108                 goto unlock;
 109         pte = pte_offset_map(pmd, addr);
 110         if (!pte)
 111                 goto unlock;
 112         ret = pte_none(*pte);
 113         pte_unmap(pte);
 114  unlock:
 115         spin_unlock(&mm->page_table_lock);
 116         return ret;
 117 }
 118
 119 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
 120                   unsigned long pfn, pgprot_t pgprot)
 121 {
 122         int ret;
 123         if (!drm_pte_is_clear(vma, addr))
 124                 return -EBUSY;
 125
 126         ret = io_remap_pfn_range(vma, addr, pfn, PAGE_SIZE, pgprot);
 127         return ret;
 128 }
 129
 130 static struct {
 131         spinlock_t lock;
 132         struct page *dummy_page;
 133         atomic_t present;
 134 } drm_np_retry =
 135 {SPIN_LOCK_UNLOCKED, NOPAGE_OOM, ATOMIC_INIT(0)};
 136
 137 struct page * get_nopage_retry(void)
 138 {
 139         if (atomic_read(&drm_np_retry.present) == 0) {
 140                 struct page *page = alloc_page(GFP_KERNEL);
 141                 if (!page)
 142                         return NOPAGE_OOM;
 143                 spin_lock(&drm_np_retry.lock);
 144                 drm_np_retry.dummy_page = page;
 145                 atomic_set(&drm_np_retry.present,1);
 146                 spin_unlock(&drm_np_retry.lock);
 147         }
 148         get_page(drm_np_retry.dummy_page);
 149         return drm_np_retry.dummy_page;
 150 }
 151
 152 void free_nopage_retry(void)
 153 {
 154         if (atomic_read(&drm_np_retry.present) == 1) {
 155                 spin_lock(&drm_np_retry.lock);
 156                 __free_page(drm_np_retry.dummy_page);
 157                 drm_np_retry.dummy_page = NULL;
 158                 atomic_set(&drm_np_retry.present, 0);
 159                 spin_unlock(&drm_np_retry.lock);
 160         }
 161 }
 162
 163 struct page *drm_vm_ttm_nopage(struct vm_area_struct *vma,
 164                                unsigned long address,
 165                                int *type)
 166 {
 167         struct fault_data data;
 168
 169         if (type)
 170                 *type = VM_FAULT_MINOR;
 171
 172         data.address = address;
 173         data.vma = vma;
 174         drm_vm_ttm_fault(vma, &data);
 175         switch (data.type) {
 176         case VM_FAULT_OOM:
 177                 return NOPAGE_OOM;
 178         case VM_FAULT_SIGBUS:
 179                 return NOPAGE_SIGBUS;
 180         default:
 181                 break;
 182         }
 183
 184         return NOPAGE_REFAULT;
 185 }
 186
 187 #endif
 188
 189 #ifdef DRM_ODD_MM_COMPAT
 190
 191 /*
 192  * VM compatibility code for 2.6.15-2.6.19(?). This code implements a complicated
 193  * workaround for a single BUG statement in do_no_page in these versions. The
 194  * tricky thing is that we need to take the mmap_sem in exclusive mode for _all_
 195  * vmas mapping the ttm, before dev->struct_mutex is taken. The way we do this is to
 196  * check first take the dev->struct_mutex, and then trylock all mmap_sems. If this
 197  * fails for a single mmap_sem, we have to release all sems and the dev->struct_mutex,
 198  * release the cpu and retry. We also need to keep track of all vmas mapping the ttm.
 199  * phew.
 200  */
 201
 202 typedef struct p_mm_entry {
 203         struct list_head head;
 204         struct mm_struct *mm;
 205         atomic_t refcount;
 206         int locked;
 207 } p_mm_entry_t;
 208
 209 typedef struct vma_entry {
 210         struct list_head head;
 211         struct vm_area_struct *vma;
 212 } vma_entry_t;
 213
 214
 215 struct page *drm_vm_ttm_nopage(struct vm_area_struct *vma,
 216                                unsigned long address,
 217                                int *type)
 218 {
 219         drm_local_map_t *map = (drm_local_map_t *) vma->vm_private_data;
 220         unsigned long page_offset;
 221         struct page *page;
 222         drm_ttm_t *ttm;
 223         drm_buffer_manager_t *bm;
 224         drm_device_t *dev;
 225
 226         /*
 227          * FIXME: Check can't map aperture flag.
 228          */
 229
 230         if (type)
 231                 *type = VM_FAULT_MINOR;
 232
 233         if (!map)
 234                 return NOPAGE_OOM;
 235
 236         if (address > vma->vm_end)
 237                 return NOPAGE_SIGBUS;
 238
 239         ttm = (drm_ttm_t *) map->offset;
 240         dev = ttm->dev;
 241         mutex_lock(&dev->struct_mutex);
 242         drm_fixup_ttm_caching(ttm);
 243         BUG_ON(ttm->page_flags & DRM_TTM_PAGE_UNCACHED);
 244
 245         bm = &dev->bm;
 246         page_offset = (address - vma->vm_start) >> PAGE_SHIFT;
 247         page = ttm->pages[page_offset];
 248
 249         if (!page) {
 250                 if (drm_alloc_memctl(PAGE_SIZE)) {
 251                         page = NOPAGE_OOM;
 252                         goto out;
 253                 }
 254                 page = ttm->pages[page_offset] = drm_alloc_gatt_pages(0);
 255                 if (!page) {
 256                         drm_free_memctl(PAGE_SIZE);
 257                         page = NOPAGE_OOM;
 258                         goto out;
 259                 }
 260                 ++bm->cur_pages;
 261                 SetPageLocked(page);
 262         }
 263
 264         get_page(page);
 265  out:
 266         mutex_unlock(&dev->struct_mutex);
 267         return page;
 268 }
 269
 270
 271
 272
 273 int drm_ttm_map_bound(struct vm_area_struct *vma)
 274 {
 275         drm_local_map_t *map = (drm_local_map_t *)vma->vm_private_data;
 276         drm_ttm_t *ttm = (drm_ttm_t *) map->offset;
 277         int ret = 0;
 278
 279         if (ttm->page_flags & DRM_TTM_PAGE_UNCACHED) {
 280                 unsigned long pfn = ttm->aper_offset +
 281                         (ttm->be->aperture_base >> PAGE_SHIFT);
 282                 pgprot_t pgprot = drm_io_prot(ttm->be->drm_map_type, vma);
 283
 284                 ret = io_remap_pfn_range(vma, vma->vm_start, pfn,
 285                                          vma->vm_end - vma->vm_start,
 286                                          pgprot);
 287         }
 288         return ret;
 289 }
 290
 291
 292 int drm_ttm_add_vma(drm_ttm_t * ttm, struct vm_area_struct *vma)
 293 {
 294         p_mm_entry_t *entry, *n_entry;
 295         vma_entry_t *v_entry;
 296         drm_local_map_t *map = (drm_local_map_t *)
 297                 vma->vm_private_data;
 298         struct mm_struct *mm = vma->vm_mm;
 299
 300         v_entry = drm_ctl_alloc(sizeof(*v_entry), DRM_MEM_TTM);
 301         if (!v_entry) {
 302                 DRM_ERROR("Allocation of vma pointer entry failed\n");
 303                 return -ENOMEM;
 304         }
 305         v_entry->vma = vma;
 306         map->handle = (void *) v_entry;
 307         list_add_tail(&v_entry->head, &ttm->vma_list);
 308
 309         list_for_each_entry(entry, &ttm->p_mm_list, head) {
 310                 if (mm == entry->mm) {
 311                         atomic_inc(&entry->refcount);
 312                         return 0;
 313                 } else if ((unsigned long)mm < (unsigned long)entry->mm) ;
 314         }
 315
 316         n_entry = drm_ctl_alloc(sizeof(*n_entry), DRM_MEM_TTM);
 317         if (!n_entry) {
 318                 DRM_ERROR("Allocation of process mm pointer entry failed\n");
 319                 return -ENOMEM;
 320         }
 321         INIT_LIST_HEAD(&n_entry->head);
 322         n_entry->mm = mm;
 323         n_entry->locked = 0;
 324         atomic_set(&n_entry->refcount, 0);
 325         list_add_tail(&n_entry->head, &entry->head);
 326
 327         return 0;
 328 }
 329
 330 void drm_ttm_delete_vma(drm_ttm_t * ttm, struct vm_area_struct *vma)
 331 {
 332         p_mm_entry_t *entry, *n;
 333         vma_entry_t *v_entry, *v_n;
 334         int found = 0;
 335         struct mm_struct *mm = vma->vm_mm;
 336
 337         list_for_each_entry_safe(v_entry, v_n, &ttm->vma_list, head) {
 338                 if (v_entry->vma == vma) {
 339                         found = 1;
 340                         list_del(&v_entry->head);
 341                         drm_ctl_free(v_entry, sizeof(*v_entry), DRM_MEM_TTM);
 342                         break;
 343                 }
 344         }
 345         BUG_ON(!found);
 346
 347         list_for_each_entry_safe(entry, n, &ttm->p_mm_list, head) {
 348                 if (mm == entry->mm) {
 349                         if (atomic_add_negative(-1, &entry->refcount)) {
 350                                 list_del(&entry->head);
 351                                 BUG_ON(entry->locked);
 352                                 drm_ctl_free(entry, sizeof(*entry), DRM_MEM_TTM);
 353                         }
 354                         return;
 355                 }
 356         }
 357         BUG_ON(1);
 358 }
 359
 360
 361
 362 int drm_ttm_lock_mm(drm_ttm_t * ttm)
 363 {
 364         p_mm_entry_t *entry;
 365         int lock_ok = 1;
 366
 367         list_for_each_entry(entry, &ttm->p_mm_list, head) {
 368                 BUG_ON(entry->locked);
 369                 if (!down_write_trylock(&entry->mm->mmap_sem)) {
 370                         lock_ok = 0;
 371                         break;
 372                 }
 373                 entry->locked = 1;
 374         }
 375
 376         if (lock_ok)
 377                 return 0;
 378
 379         list_for_each_entry(entry, &ttm->p_mm_list, head) {
 380                 if (!entry->locked)
 381                         break;
 382                 up_write(&entry->mm->mmap_sem);
 383                 entry->locked = 0;
 384         }
 385
 386         /*
 387          * Possible deadlock. Try again. Our callers should handle this
 388          * and restart.
 389          */
 390
 391         return -EAGAIN;
 392 }
 393
 394 void drm_ttm_unlock_mm(drm_ttm_t * ttm)
 395 {
 396         p_mm_entry_t *entry;
 397
 398         list_for_each_entry(entry, &ttm->p_mm_list, head) {
 399                 BUG_ON(!entry->locked);
 400                 up_write(&entry->mm->mmap_sem);
 401                 entry->locked = 0;
 402         }
 403 }
 404
 405 int drm_ttm_remap_bound(drm_ttm_t *ttm)
 406 {
 407         vma_entry_t *v_entry;
 408         int ret = 0;
 409
 410         list_for_each_entry(v_entry, &ttm->vma_list, head) {
 411                 ret = drm_ttm_map_bound(v_entry->vma);
 412                 if (ret)
 413                         break;
 414         }
 415
 416         drm_ttm_unlock_mm(ttm);
 417         return ret;
 418 }
 419
 420 void drm_ttm_finish_unmap(drm_ttm_t *ttm)
 421 {
 422         vma_entry_t *v_entry;
 423
 424         if (!(ttm->page_flags & DRM_TTM_PAGE_UNCACHED))
 425                 return;
 426
 427         list_for_each_entry(v_entry, &ttm->vma_list, head) {
 428                 v_entry->vma->vm_flags &= ~VM_PFNMAP;
 429         }
 430         drm_ttm_unlock_mm(ttm);
 431 }
 432
 433 #endif
 434