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 *$FreeBSD: head/sys/dev/drm2/ttm/ttm_bo_vm.c 253710 2013-07-27 16:44:37Z kib $ 38 */ 39 40 #include "opt_vm.h" 41 42 #define pr_fmt(fmt) "[TTM] " fmt 43 44 #include <drm/ttm/ttm_module.h> 45 #include <drm/ttm/ttm_bo_driver.h> 46 #include <drm/ttm/ttm_placement.h> 47 #include <vm/vm.h> 48 #include <vm/vm_page.h> 49 #include <linux/errno.h> 50 #include <linux/export.h> 51 52 RB_GENERATE(ttm_bo_device_buffer_objects, ttm_buffer_object, vm_rb, 53 ttm_bo_cmp_rb_tree_items); 54 55 56 #define TTM_BO_VM_NUM_PREFAULT 16 57 58 int 59 ttm_bo_cmp_rb_tree_items(struct ttm_buffer_object *a, 60 struct ttm_buffer_object *b) 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 72 static struct ttm_buffer_object *ttm_bo_vm_lookup_rb(struct ttm_bo_device *bdev, 73 unsigned long page_start, 74 unsigned long num_pages) 75 { 76 unsigned long cur_offset; 77 struct ttm_buffer_object *bo; 78 struct ttm_buffer_object *best_bo = NULL; 79 80 bo = RB_ROOT(&bdev->addr_space_rb); 81 while (bo != NULL) { 82 cur_offset = bo->vm_node->start; 83 if (page_start >= cur_offset) { 84 best_bo = bo; 85 if (page_start == cur_offset) 86 break; 87 bo = RB_RIGHT(bo, vm_rb); 88 } else 89 bo = RB_LEFT(bo, vm_rb); 90 } 91 92 if (unlikely(best_bo == NULL)) 93 return NULL; 94 95 if (unlikely((best_bo->vm_node->start + best_bo->num_pages) < 96 (page_start + num_pages))) 97 return NULL; 98 99 return best_bo; 100 } 101 102 static int 103 ttm_bo_vm_fault(vm_object_t vm_obj, vm_ooffset_t offset, 104 int prot, vm_page_t *mres) 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, oldm; 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 oldm = *mres; 117 if (oldm != NULL) { 118 vm_page_remove(oldm); 119 *mres = NULL; 120 } else 121 oldm = NULL; 122 retry: 123 VM_OBJECT_UNLOCK(vm_obj); 124 m = NULL; 125 126 reserve: 127 ret = ttm_bo_reserve(bo, false, false, false, 0); 128 if (unlikely(ret != 0)) { 129 if (ret == -EBUSY) { 130 lwkt_yield(); 131 goto reserve; 132 } 133 } 134 135 if (bdev->driver->fault_reserve_notify) { 136 ret = bdev->driver->fault_reserve_notify(bo); 137 switch (ret) { 138 case 0: 139 break; 140 case -EBUSY: 141 case -ERESTARTSYS: 142 case -EINTR: 143 lwkt_yield(); 144 goto reserve; 145 default: 146 retval = VM_PAGER_ERROR; 147 goto out_unlock; 148 } 149 } 150 151 /* 152 * Wait for buffer data in transit, due to a pipelined 153 * move. 154 */ 155 156 lockmgr(&bdev->fence_lock, LK_EXCLUSIVE); 157 if (test_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags)) { 158 /* 159 * Here, the behavior differs between Linux and FreeBSD. 160 * 161 * On Linux, the wait is interruptible (3rd argument to 162 * ttm_bo_wait). There must be some mechanism to resume 163 * page fault handling, once the signal is processed. 164 * 165 * On FreeBSD, the wait is uninteruptible. This is not a 166 * problem as we can't end up with an unkillable process 167 * here, because the wait will eventually time out. 168 * 169 * An example of this situation is the Xorg process 170 * which uses SIGALRM internally. The signal could 171 * interrupt the wait, causing the page fault to fail 172 * and the process to receive SIGSEGV. 173 */ 174 ret = ttm_bo_wait(bo, false, false, false); 175 lockmgr(&bdev->fence_lock, LK_RELEASE); 176 if (unlikely(ret != 0)) { 177 retval = VM_PAGER_ERROR; 178 goto out_unlock; 179 } 180 } else 181 lockmgr(&bdev->fence_lock, LK_RELEASE); 182 183 ret = ttm_mem_io_lock(man, true); 184 if (unlikely(ret != 0)) { 185 retval = VM_PAGER_ERROR; 186 goto out_unlock; 187 } 188 ret = ttm_mem_io_reserve_vm(bo); 189 if (unlikely(ret != 0)) { 190 retval = VM_PAGER_ERROR; 191 goto out_io_unlock; 192 } 193 194 /* 195 * Strictly, we're not allowed to modify vma->vm_page_prot here, 196 * since the mmap_sem is only held in read mode. However, we 197 * modify only the caching bits of vma->vm_page_prot and 198 * consider those bits protected by 199 * the bo->mutex, as we should be the only writers. 200 * There shouldn't really be any readers of these bits except 201 * within vm_insert_mixed()? fork? 202 * 203 * TODO: Add a list of vmas to the bo, and change the 204 * vma->vm_page_prot when the object changes caching policy, with 205 * the correct locks held. 206 */ 207 if (!bo->mem.bus.is_iomem) { 208 /* Allocate all page at once, most common usage */ 209 ttm = bo->ttm; 210 if (ttm->bdev->driver->ttm_tt_populate(ttm)) { 211 retval = VM_PAGER_ERROR; 212 goto out_io_unlock; 213 } 214 } 215 216 if (bo->mem.bus.is_iomem) { 217 m = vm_phys_fictitious_to_vm_page(bo->mem.bus.base + 218 bo->mem.bus.offset + offset); 219 pmap_page_set_memattr(m, ttm_io_prot(bo->mem.placement)); 220 } else { 221 ttm = bo->ttm; 222 m = (struct vm_page *)ttm->pages[OFF_TO_IDX(offset)]; 223 if (unlikely(!m)) { 224 retval = VM_PAGER_ERROR; 225 goto out_io_unlock; 226 } 227 pmap_page_set_memattr(m, 228 (bo->mem.placement & TTM_PL_FLAG_CACHED) ? 229 VM_MEMATTR_WRITE_BACK : ttm_io_prot(bo->mem.placement)); 230 } 231 232 VM_OBJECT_LOCK(vm_obj); 233 if ((m->busy_count & PBUSY_LOCKED) != 0) { 234 #if 0 235 vm_page_sleep(m, "ttmpbs"); 236 #endif 237 ttm_mem_io_unlock(man); 238 ttm_bo_unreserve(bo); 239 goto retry; 240 } 241 m->valid = VM_PAGE_BITS_ALL; 242 *mres = m; 243 m1 = vm_page_lookup(vm_obj, OFF_TO_IDX(offset)); 244 if (m1 == NULL) { 245 vm_page_insert(m, vm_obj, OFF_TO_IDX(offset)); 246 } else { 247 KASSERT(m == m1, 248 ("inconsistent insert bo %p m %p m1 %p offset %jx", 249 bo, m, m1, (uintmax_t)offset)); 250 } 251 vm_page_busy_try(m, FALSE); 252 253 if (oldm != NULL) { 254 vm_page_free(oldm); 255 } 256 257 out_io_unlock1: 258 ttm_mem_io_unlock(man); 259 out_unlock1: 260 ttm_bo_unreserve(bo); 261 vm_object_pip_wakeup(vm_obj); 262 return (retval); 263 264 out_io_unlock: 265 VM_OBJECT_LOCK(vm_obj); 266 goto out_io_unlock1; 267 268 out_unlock: 269 VM_OBJECT_LOCK(vm_obj); 270 goto out_unlock1; 271 } 272 273 static int 274 ttm_bo_vm_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot, 275 vm_ooffset_t foff, struct ucred *cred, u_short *color) 276 { 277 278 /* 279 * On Linux, a reference to the buffer object is acquired here. 280 * The reason is that this function is not called when the 281 * mmap() is initialized, but only when a process forks for 282 * instance. Therefore on Linux, the reference on the bo is 283 * acquired either in ttm_bo_mmap() or ttm_bo_vm_open(). It's 284 * then released in ttm_bo_vm_close(). 285 * 286 * Here, this function is called during mmap() intialization. 287 * Thus, the reference acquired in ttm_bo_mmap_single() is 288 * sufficient. 289 */ 290 *color = 0; 291 return (0); 292 } 293 294 static void 295 ttm_bo_vm_dtor(void *handle) 296 { 297 struct ttm_buffer_object *bo = handle; 298 299 ttm_bo_unref(&bo); 300 } 301 302 static struct cdev_pager_ops ttm_pager_ops = { 303 .cdev_pg_fault = ttm_bo_vm_fault, 304 .cdev_pg_ctor = ttm_bo_vm_ctor, 305 .cdev_pg_dtor = ttm_bo_vm_dtor 306 }; 307 308 int 309 ttm_bo_mmap_single(struct ttm_bo_device *bdev, vm_ooffset_t *offset, vm_size_t size, 310 struct vm_object **obj_res, int nprot) 311 { 312 struct ttm_bo_driver *driver; 313 struct ttm_buffer_object *bo; 314 struct vm_object *vm_obj; 315 int ret; 316 317 *obj_res = NULL; 318 319 lockmgr(&bdev->vm_lock, LK_EXCLUSIVE); 320 bo = ttm_bo_vm_lookup_rb(bdev, OFF_TO_IDX(*offset), OFF_TO_IDX(size)); 321 if (likely(bo != NULL)) 322 kref_get(&bo->kref); 323 lockmgr(&bdev->vm_lock, LK_RELEASE); 324 325 if (unlikely(bo == NULL)) { 326 pr_err("Could not find buffer object to map\n"); 327 return (EINVAL); 328 } 329 330 driver = bo->bdev->driver; 331 if (unlikely(!driver->verify_access)) { 332 ret = EPERM; 333 goto out_unref; 334 } 335 ret = -driver->verify_access(bo); 336 if (unlikely(ret != 0)) 337 goto out_unref; 338 339 vm_obj = cdev_pager_allocate(bo, OBJT_MGTDEVICE, &ttm_pager_ops, 340 size, nprot, 0, curthread->td_ucred); 341 342 if (vm_obj == NULL) { 343 ret = EINVAL; 344 goto out_unref; 345 } 346 /* 347 * Note: We're transferring the bo reference to vm_obj->handle here. 348 */ 349 *offset = 0; 350 *obj_res = vm_obj; 351 return 0; 352 out_unref: 353 ttm_bo_unref(&bo); 354 return ret; 355 } 356 EXPORT_SYMBOL(ttm_bo_mmap); 357 358 void 359 ttm_bo_release_mmap(struct ttm_buffer_object *bo) 360 { 361 vm_object_t vm_obj; 362 vm_page_t m; 363 int i; 364 365 vm_obj = cdev_pager_lookup(bo); 366 if (vm_obj == NULL) 367 return; 368 369 VM_OBJECT_LOCK(vm_obj); 370 for (i = 0; i < bo->num_pages; i++) { 371 m = vm_page_lookup_busy_wait(vm_obj, i, TRUE, "ttm_unm"); 372 if (m == NULL) 373 continue; 374 cdev_pager_free_page(vm_obj, m); 375 } 376 VM_OBJECT_UNLOCK(vm_obj); 377 378 vm_object_deallocate(vm_obj); 379 } 380 381 #if 0 382 int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo) 383 { 384 if (vma->vm_pgoff != 0) 385 return -EACCES; 386 387 vma->vm_ops = &ttm_bo_vm_ops; 388 vma->vm_private_data = ttm_bo_reference(bo); 389 vma->vm_flags |= VM_IO | VM_MIXEDMAP | VM_DONTEXPAND; 390 return 0; 391 } 392 EXPORT_SYMBOL(ttm_fbdev_mmap); 393 #endif 394