The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/dev/drm2/ttm/ttm_bo_vm.c

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    1 /**************************************************************************
    2  *
    3  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
    4  * All Rights Reserved.
    5  *
    6  * Permission is hereby granted, free of charge, to any person obtaining a
    7  * copy of this software and associated documentation files (the
    8  * "Software"), to deal in the Software without restriction, including
    9  * without limitation the rights to use, copy, modify, merge, publish,
   10  * distribute, sub license, and/or sell copies of the Software, and to
   11  * permit persons to whom the Software is furnished to do so, subject to
   12  * the following conditions:
   13  *
   14  * The above copyright notice and this permission notice (including the
   15  * next paragraph) shall be included in all copies or substantial portions
   16  * of the Software.
   17  *
   18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
   21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
   22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
   23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
   24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
   25  *
   26  **************************************************************************/
   27 /*
   28  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
   29  */
   30 /*
   31  * Copyright (c) 2013 The FreeBSD Foundation
   32  * All rights reserved.
   33  *
   34  * Portions of this software were developed by Konstantin Belousov
   35  * <kib@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
   36  */
   37 
   38 #include <sys/cdefs.h>
   39 __FBSDID("$FreeBSD$");
   40 
   41 #include "opt_vm.h"
   42 
   43 #include <dev/drm2/drmP.h>
   44 #include <dev/drm2/ttm/ttm_module.h>
   45 #include <dev/drm2/ttm/ttm_bo_driver.h>
   46 #include <dev/drm2/ttm/ttm_placement.h>
   47 
   48 #include <vm/vm.h>
   49 #include <vm/vm_page.h>
   50 #include <vm/vm_pageout.h>
   51 
   52 #define TTM_BO_VM_NUM_PREFAULT 16
   53 
   54 RB_GENERATE(ttm_bo_device_buffer_objects, ttm_buffer_object, vm_rb,
   55     ttm_bo_cmp_rb_tree_items);
   56 
   57 int
   58 ttm_bo_cmp_rb_tree_items(struct ttm_buffer_object *a,
   59     struct ttm_buffer_object *b)
   60 {
   61 
   62         if (a->vm_node->start < b->vm_node->start) {
   63                 return (-1);
   64         } else if (a->vm_node->start > b->vm_node->start) {
   65                 return (1);
   66         } else {
   67                 return (0);
   68         }
   69 }
   70 
   71 static struct ttm_buffer_object *ttm_bo_vm_lookup_rb(struct ttm_bo_device *bdev,
   72                                                      unsigned long page_start,
   73                                                      unsigned long num_pages)
   74 {
   75         unsigned long cur_offset;
   76         struct ttm_buffer_object *bo;
   77         struct ttm_buffer_object *best_bo = NULL;
   78 
   79         bo = RB_ROOT(&bdev->addr_space_rb);
   80         while (bo != NULL) {
   81                 cur_offset = bo->vm_node->start;
   82                 if (page_start >= cur_offset) {
   83                         best_bo = bo;
   84                         if (page_start == cur_offset)
   85                                 break;
   86                         bo = RB_RIGHT(bo, vm_rb);
   87                 } else
   88                         bo = RB_LEFT(bo, vm_rb);
   89         }
   90 
   91         if (unlikely(best_bo == NULL))
   92                 return NULL;
   93 
   94         if (unlikely((best_bo->vm_node->start + best_bo->num_pages) <
   95                      (page_start + num_pages)))
   96                 return NULL;
   97 
   98         return best_bo;
   99 }
  100 
  101 static int
  102 ttm_bo_vm_fault(vm_object_t vm_obj, vm_ooffset_t offset,
  103     int prot, vm_page_t *mres)
  104 {
  105 
  106         struct ttm_buffer_object *bo = vm_obj->handle;
  107         struct ttm_bo_device *bdev = bo->bdev;
  108         struct ttm_tt *ttm = NULL;
  109         vm_page_t m, m1;
  110         int ret;
  111         int retval = VM_PAGER_OK;
  112         struct ttm_mem_type_manager *man =
  113                 &bdev->man[bo->mem.mem_type];
  114 
  115         vm_object_pip_add(vm_obj, 1);
  116         if (*mres != NULL) {
  117                 (void)vm_page_remove(*mres);
  118         }
  119 retry:
  120         VM_OBJECT_WUNLOCK(vm_obj);
  121         m = NULL;
  122 
  123 reserve:
  124         ret = ttm_bo_reserve(bo, false, false, false, 0);
  125         if (unlikely(ret != 0)) {
  126                 if (ret == -EBUSY) {
  127                         kern_yield(PRI_USER);
  128                         goto reserve;
  129                 }
  130         }
  131 
  132         if (bdev->driver->fault_reserve_notify) {
  133                 ret = bdev->driver->fault_reserve_notify(bo);
  134                 switch (ret) {
  135                 case 0:
  136                         break;
  137                 case -EBUSY:
  138                 case -ERESTARTSYS:
  139                 case -EINTR:
  140                         kern_yield(PRI_USER);
  141                         goto reserve;
  142                 default:
  143                         retval = VM_PAGER_ERROR;
  144                         goto out_unlock;
  145                 }
  146         }
  147 
  148         /*
  149          * Wait for buffer data in transit, due to a pipelined
  150          * move.
  151          */
  152 
  153         mtx_lock(&bdev->fence_lock);
  154         if (test_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags)) {
  155                 /*
  156                  * Here, the behavior differs between Linux and FreeBSD.
  157                  *
  158                  * On Linux, the wait is interruptible (3rd argument to
  159                  * ttm_bo_wait). There must be some mechanism to resume
  160                  * page fault handling, once the signal is processed.
  161                  *
  162                  * On FreeBSD, the wait is uninteruptible. This is not a
  163                  * problem as we can't end up with an unkillable process
  164                  * here, because the wait will eventually time out.
  165                  *
  166                  * An example of this situation is the Xorg process
  167                  * which uses SIGALRM internally. The signal could
  168                  * interrupt the wait, causing the page fault to fail
  169                  * and the process to receive SIGSEGV.
  170                  */
  171                 ret = ttm_bo_wait(bo, false, false, false);
  172                 mtx_unlock(&bdev->fence_lock);
  173                 if (unlikely(ret != 0)) {
  174                         retval = VM_PAGER_ERROR;
  175                         goto out_unlock;
  176                 }
  177         } else
  178                 mtx_unlock(&bdev->fence_lock);
  179 
  180         ret = ttm_mem_io_lock(man, true);
  181         if (unlikely(ret != 0)) {
  182                 retval = VM_PAGER_ERROR;
  183                 goto out_unlock;
  184         }
  185         ret = ttm_mem_io_reserve_vm(bo);
  186         if (unlikely(ret != 0)) {
  187                 retval = VM_PAGER_ERROR;
  188                 goto out_io_unlock;
  189         }
  190 
  191         /*
  192          * Strictly, we're not allowed to modify vma->vm_page_prot here,
  193          * since the mmap_sem is only held in read mode. However, we
  194          * modify only the caching bits of vma->vm_page_prot and
  195          * consider those bits protected by
  196          * the bo->mutex, as we should be the only writers.
  197          * There shouldn't really be any readers of these bits except
  198          * within vm_insert_mixed()? fork?
  199          *
  200          * TODO: Add a list of vmas to the bo, and change the
  201          * vma->vm_page_prot when the object changes caching policy, with
  202          * the correct locks held.
  203          */
  204         if (!bo->mem.bus.is_iomem) {
  205                 /* Allocate all page at once, most common usage */
  206                 ttm = bo->ttm;
  207                 if (ttm->bdev->driver->ttm_tt_populate(ttm)) {
  208                         retval = VM_PAGER_ERROR;
  209                         goto out_io_unlock;
  210                 }
  211         }
  212 
  213         if (bo->mem.bus.is_iomem) {
  214                 m = PHYS_TO_VM_PAGE(bo->mem.bus.base + bo->mem.bus.offset +
  215                     offset);
  216                 KASSERT((m->flags & PG_FICTITIOUS) != 0,
  217                     ("physical address %#jx not fictitious",
  218                     (uintmax_t)(bo->mem.bus.base + bo->mem.bus.offset
  219                     + offset)));
  220                 pmap_page_set_memattr(m, ttm_io_prot(bo->mem.placement));
  221         } else {
  222                 ttm = bo->ttm;
  223                 m = ttm->pages[OFF_TO_IDX(offset)];
  224                 if (unlikely(!m)) {
  225                         retval = VM_PAGER_ERROR;
  226                         goto out_io_unlock;
  227                 }
  228                 pmap_page_set_memattr(m,
  229                     (bo->mem.placement & TTM_PL_FLAG_CACHED) ?
  230                     VM_MEMATTR_WRITE_BACK : ttm_io_prot(bo->mem.placement));
  231         }
  232 
  233         VM_OBJECT_WLOCK(vm_obj);
  234         if (vm_page_busy_acquire(m, VM_ALLOC_WAITFAIL) == 0) {
  235                 ttm_mem_io_unlock(man);
  236                 ttm_bo_unreserve(bo);
  237                 goto retry;
  238         }
  239         m1 = vm_page_lookup(vm_obj, OFF_TO_IDX(offset));
  240         /* XXX This looks like it should just be vm_page_replace? */
  241         if (m1 == NULL) {
  242                 if (vm_page_insert(m, vm_obj, OFF_TO_IDX(offset))) {
  243                         vm_page_xunbusy(m);
  244                         VM_OBJECT_WUNLOCK(vm_obj);
  245                         vm_wait(vm_obj);
  246                         VM_OBJECT_WLOCK(vm_obj);
  247                         ttm_mem_io_unlock(man);
  248                         ttm_bo_unreserve(bo);
  249                         goto retry;
  250                 }
  251         } else {
  252                 KASSERT(m == m1,
  253                     ("inconsistent insert bo %p m %p m1 %p offset %jx",
  254                     bo, m, m1, (uintmax_t)offset));
  255         }
  256         vm_page_valid(m);
  257         if (*mres != NULL) {
  258                 KASSERT(*mres != m, ("losing %p %p", *mres, m));
  259                 vm_page_xunbusy(*mres);
  260                 vm_page_free(*mres);
  261         }
  262         *mres = m;
  263 
  264 out_io_unlock1:
  265         ttm_mem_io_unlock(man);
  266 out_unlock1:
  267         ttm_bo_unreserve(bo);
  268         vm_object_pip_wakeup(vm_obj);
  269         return (retval);
  270 
  271 out_io_unlock:
  272         VM_OBJECT_WLOCK(vm_obj);
  273         goto out_io_unlock1;
  274 
  275 out_unlock:
  276         VM_OBJECT_WLOCK(vm_obj);
  277         goto out_unlock1;
  278 }
  279 
  280 static int
  281 ttm_bo_vm_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
  282     vm_ooffset_t foff, struct ucred *cred, u_short *color)
  283 {
  284 
  285         /*
  286          * On Linux, a reference to the buffer object is acquired here.
  287          * The reason is that this function is not called when the
  288          * mmap() is initialized, but only when a process forks for
  289          * instance. Therefore on Linux, the reference on the bo is
  290          * acquired either in ttm_bo_mmap() or ttm_bo_vm_open(). It's
  291          * then released in ttm_bo_vm_close().
  292          *
  293          * Here, this function is called during mmap() initialization.
  294          * Thus, the reference acquired in ttm_bo_mmap_single() is
  295          * sufficient.
  296          */
  297 
  298         *color = 0;
  299         return (0);
  300 }
  301 
  302 static void
  303 ttm_bo_vm_dtor(void *handle)
  304 {
  305         struct ttm_buffer_object *bo = handle;
  306 
  307         ttm_bo_unref(&bo);
  308 }
  309 
  310 static struct cdev_pager_ops ttm_pager_ops = {
  311         .cdev_pg_fault = ttm_bo_vm_fault,
  312         .cdev_pg_ctor = ttm_bo_vm_ctor,
  313         .cdev_pg_dtor = ttm_bo_vm_dtor
  314 };
  315 
  316 int
  317 ttm_bo_mmap_single(struct ttm_bo_device *bdev, vm_ooffset_t *offset, vm_size_t size,
  318     struct vm_object **obj_res, int nprot)
  319 {
  320         struct ttm_bo_driver *driver;
  321         struct ttm_buffer_object *bo;
  322         struct vm_object *vm_obj;
  323         int ret;
  324 
  325         rw_wlock(&bdev->vm_lock);
  326         bo = ttm_bo_vm_lookup_rb(bdev, OFF_TO_IDX(*offset), OFF_TO_IDX(size));
  327         if (likely(bo != NULL))
  328                 refcount_acquire(&bo->kref);
  329         rw_wunlock(&bdev->vm_lock);
  330 
  331         if (unlikely(bo == NULL)) {
  332                 printf("[TTM] Could not find buffer object to map\n");
  333                 return (-EINVAL);
  334         }
  335 
  336         driver = bo->bdev->driver;
  337         if (unlikely(!driver->verify_access)) {
  338                 ret = -EPERM;
  339                 goto out_unref;
  340         }
  341         ret = driver->verify_access(bo);
  342         if (unlikely(ret != 0))
  343                 goto out_unref;
  344 
  345         vm_obj = cdev_pager_allocate(bo, OBJT_MGTDEVICE, &ttm_pager_ops,
  346             size, nprot, 0, curthread->td_ucred);
  347         if (vm_obj == NULL) {
  348                 ret = -EINVAL;
  349                 goto out_unref;
  350         }
  351         /*
  352          * Note: We're transferring the bo reference to vm_obj->handle here.
  353          */
  354         *offset = 0;
  355         *obj_res = vm_obj;
  356         return 0;
  357 out_unref:
  358         ttm_bo_unref(&bo);
  359         return ret;
  360 }
  361 
  362 void
  363 ttm_bo_release_mmap(struct ttm_buffer_object *bo)
  364 {
  365         vm_object_t vm_obj;
  366         vm_page_t m;
  367         int i;
  368 
  369         vm_obj = cdev_pager_lookup(bo);
  370         if (vm_obj == NULL)
  371                 return;
  372 
  373         VM_OBJECT_WLOCK(vm_obj);
  374 retry:
  375         for (i = 0; i < bo->num_pages; i++) {
  376                 m = vm_page_lookup(vm_obj, i);
  377                 if (m == NULL)
  378                         continue;
  379                 if (vm_page_busy_acquire(m, VM_ALLOC_WAITFAIL) == 0)
  380                         goto retry;
  381                 cdev_pager_free_page(vm_obj, m);
  382         }
  383         VM_OBJECT_WUNLOCK(vm_obj);
  384 
  385         vm_object_deallocate(vm_obj);
  386 }
  387 
  388 #if 0
  389 int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
  390 {
  391         if (vma->vm_pgoff != 0)
  392                 return -EACCES;
  393 
  394         vma->vm_ops = &ttm_bo_vm_ops;
  395         vma->vm_private_data = ttm_bo_reference(bo);
  396         vma->vm_flags |= VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
  397         return 0;
  398 }
  399 
  400 ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
  401                   const char __user *wbuf, char __user *rbuf, size_t count,
  402                   loff_t *f_pos, bool write)
  403 {
  404         struct ttm_buffer_object *bo;
  405         struct ttm_bo_driver *driver;
  406         struct ttm_bo_kmap_obj map;
  407         unsigned long dev_offset = (*f_pos >> PAGE_SHIFT);
  408         unsigned long kmap_offset;
  409         unsigned long kmap_end;
  410         unsigned long kmap_num;
  411         size_t io_size;
  412         unsigned int page_offset;
  413         char *virtual;
  414         int ret;
  415         bool no_wait = false;
  416         bool dummy;
  417 
  418         read_lock(&bdev->vm_lock);
  419         bo = ttm_bo_vm_lookup_rb(bdev, dev_offset, 1);
  420         if (likely(bo != NULL))
  421                 ttm_bo_reference(bo);
  422         read_unlock(&bdev->vm_lock);
  423 
  424         if (unlikely(bo == NULL))
  425                 return -EFAULT;
  426 
  427         driver = bo->bdev->driver;
  428         if (unlikely(!driver->verify_access)) {
  429                 ret = -EPERM;
  430                 goto out_unref;
  431         }
  432 
  433         ret = driver->verify_access(bo, filp);
  434         if (unlikely(ret != 0))
  435                 goto out_unref;
  436 
  437         kmap_offset = dev_offset - bo->vm_node->start;
  438         if (unlikely(kmap_offset >= bo->num_pages)) {
  439                 ret = -EFBIG;
  440                 goto out_unref;
  441         }
  442 
  443         page_offset = *f_pos & ~PAGE_MASK;
  444         io_size = bo->num_pages - kmap_offset;
  445         io_size = (io_size << PAGE_SHIFT) - page_offset;
  446         if (count < io_size)
  447                 io_size = count;
  448 
  449         kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
  450         kmap_num = kmap_end - kmap_offset + 1;
  451 
  452         ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
  453 
  454         switch (ret) {
  455         case 0:
  456                 break;
  457         case -EBUSY:
  458                 ret = -EAGAIN;
  459                 goto out_unref;
  460         default:
  461                 goto out_unref;
  462         }
  463 
  464         ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
  465         if (unlikely(ret != 0)) {
  466                 ttm_bo_unreserve(bo);
  467                 goto out_unref;
  468         }
  469 
  470         virtual = ttm_kmap_obj_virtual(&map, &dummy);
  471         virtual += page_offset;
  472 
  473         if (write)
  474                 ret = copy_from_user(virtual, wbuf, io_size);
  475         else
  476                 ret = copy_to_user(rbuf, virtual, io_size);
  477 
  478         ttm_bo_kunmap(&map);
  479         ttm_bo_unreserve(bo);
  480         ttm_bo_unref(&bo);
  481 
  482         if (unlikely(ret != 0))
  483                 return -EFBIG;
  484 
  485         *f_pos += io_size;
  486 
  487         return io_size;
  488 out_unref:
  489         ttm_bo_unref(&bo);
  490         return ret;
  491 }
  492 
  493 ssize_t ttm_bo_fbdev_io(struct ttm_buffer_object *bo, const char __user *wbuf,
  494                         char __user *rbuf, size_t count, loff_t *f_pos,
  495                         bool write)
  496 {
  497         struct ttm_bo_kmap_obj map;
  498         unsigned long kmap_offset;
  499         unsigned long kmap_end;
  500         unsigned long kmap_num;
  501         size_t io_size;
  502         unsigned int page_offset;
  503         char *virtual;
  504         int ret;
  505         bool no_wait = false;
  506         bool dummy;
  507 
  508         kmap_offset = (*f_pos >> PAGE_SHIFT);
  509         if (unlikely(kmap_offset >= bo->num_pages))
  510                 return -EFBIG;
  511 
  512         page_offset = *f_pos & ~PAGE_MASK;
  513         io_size = bo->num_pages - kmap_offset;
  514         io_size = (io_size << PAGE_SHIFT) - page_offset;
  515         if (count < io_size)
  516                 io_size = count;
  517 
  518         kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
  519         kmap_num = kmap_end - kmap_offset + 1;
  520 
  521         ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
  522 
  523         switch (ret) {
  524         case 0:
  525                 break;
  526         case -EBUSY:
  527                 return -EAGAIN;
  528         default:
  529                 return ret;
  530         }
  531 
  532         ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
  533         if (unlikely(ret != 0)) {
  534                 ttm_bo_unreserve(bo);
  535                 return ret;
  536         }
  537 
  538         virtual = ttm_kmap_obj_virtual(&map, &dummy);
  539         virtual += page_offset;
  540 
  541         if (write)
  542                 ret = copy_from_user(virtual, wbuf, io_size);
  543         else
  544                 ret = copy_to_user(rbuf, virtual, io_size);
  545 
  546         ttm_bo_kunmap(&map);
  547         ttm_bo_unreserve(bo);
  548         ttm_bo_unref(&bo);
  549 
  550         if (unlikely(ret != 0))
  551                 return ret;
  552 
  553         *f_pos += io_size;
  554 
  555         return io_size;
  556 }
  557 #endif

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