1 /*
2 * SPDX-License-Identifier: MIT
3 *
4 * Copyright © 2014-2016 Intel Corporation
5 */
6
7 #include <linux/anon_inodes.h>
8 #include <linux/mman.h>
9 #include <linux/pfn_t.h>
10 #include <linux/sizes.h>
11
12 #include <drm/drm_cache.h>
13
14 #include "gt/intel_gt.h"
15 #include "gt/intel_gt_requests.h"
16
17 #include "i915_drv.h"
18 #include "i915_gem_evict.h"
19 #include "i915_gem_gtt.h"
20 #include "i915_gem_ioctls.h"
21 #include "i915_gem_object.h"
22 #include "i915_gem_mman.h"
23 #include "i915_mm.h"
24 #include "i915_trace.h"
25 #include "i915_user_extensions.h"
26 #include "i915_gem_ttm.h"
27 #include "i915_vma.h"
28
29 static inline bool
__vma_matches(struct vm_area_struct * vma,struct file * filp,unsigned long addr,unsigned long size)30 __vma_matches(struct vm_area_struct *vma, struct file *filp,
31 unsigned long addr, unsigned long size)
32 {
33 if (vma->vm_file != filp)
34 return false;
35
36 return vma->vm_start == addr &&
37 (vma->vm_end - vma->vm_start) == PAGE_ALIGN(size);
38 }
39
40 /**
41 * i915_gem_mmap_ioctl - Maps the contents of an object, returning the address
42 * it is mapped to.
43 * @dev: drm device
44 * @data: ioctl data blob
45 * @file: drm file
46 *
47 * While the mapping holds a reference on the contents of the object, it doesn't
48 * imply a ref on the object itself.
49 *
50 * IMPORTANT:
51 *
52 * DRM driver writers who look a this function as an example for how to do GEM
53 * mmap support, please don't implement mmap support like here. The modern way
54 * to implement DRM mmap support is with an mmap offset ioctl (like
55 * i915_gem_mmap_gtt) and then using the mmap syscall on the DRM fd directly.
56 * That way debug tooling like valgrind will understand what's going on, hiding
57 * the mmap call in a driver private ioctl will break that. The i915 driver only
58 * does cpu mmaps this way because we didn't know better.
59 */
60 int
i915_gem_mmap_ioctl(struct drm_device * dev,void * data,struct drm_file * file)61 i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
62 struct drm_file *file)
63 {
64 struct drm_i915_private *i915 = to_i915(dev);
65 struct drm_i915_gem_mmap *args = data;
66 struct drm_i915_gem_object *obj;
67 unsigned long addr;
68
69 /*
70 * mmap ioctl is disallowed for all discrete platforms,
71 * and for all platforms with GRAPHICS_VER > 12.
72 */
73 if (IS_DGFX(i915) || GRAPHICS_VER_FULL(i915) > IP_VER(12, 0))
74 return -EOPNOTSUPP;
75
76 if (args->flags & ~(I915_MMAP_WC))
77 return -EINVAL;
78
79 if (args->flags & I915_MMAP_WC && !pat_enabled())
80 return -ENODEV;
81
82 obj = i915_gem_object_lookup(file, args->handle);
83 if (!obj)
84 return -ENOENT;
85
86 /* prime objects have no backing filp to GEM mmap
87 * pages from.
88 */
89 if (!obj->base.filp) {
90 addr = -ENXIO;
91 goto err;
92 }
93
94 if (range_overflows(args->offset, args->size, (u64)obj->base.size)) {
95 addr = -EINVAL;
96 goto err;
97 }
98
99 addr = vm_mmap(obj->base.filp, 0, args->size,
100 PROT_READ | PROT_WRITE, MAP_SHARED,
101 args->offset);
102 if (IS_ERR_VALUE(addr))
103 goto err;
104
105 if (args->flags & I915_MMAP_WC) {
106 struct mm_struct *mm = current->mm;
107 struct vm_area_struct *vma;
108
109 if (mmap_write_lock_killable(mm)) {
110 addr = -EINTR;
111 goto err;
112 }
113 vma = find_vma(mm, addr);
114 if (vma && __vma_matches(vma, obj->base.filp, addr, args->size))
115 vma->vm_page_prot =
116 pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
117 else
118 addr = -ENOMEM;
119 mmap_write_unlock(mm);
120 if (IS_ERR_VALUE(addr))
121 goto err;
122 }
123 i915_gem_object_put(obj);
124
125 args->addr_ptr = (u64)addr;
126 return 0;
127
128 err:
129 i915_gem_object_put(obj);
130 return addr;
131 }
132
tile_row_pages(const struct drm_i915_gem_object * obj)133 static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
134 {
135 return i915_gem_object_get_tile_row_size(obj) >> PAGE_SHIFT;
136 }
137
138 /**
139 * i915_gem_mmap_gtt_version - report the current feature set for GTT mmaps
140 *
141 * A history of the GTT mmap interface:
142 *
143 * 0 - Everything had to fit into the GTT. Both parties of a memcpy had to
144 * aligned and suitable for fencing, and still fit into the available
145 * mappable space left by the pinned display objects. A classic problem
146 * we called the page-fault-of-doom where we would ping-pong between
147 * two objects that could not fit inside the GTT and so the memcpy
148 * would page one object in at the expense of the other between every
149 * single byte.
150 *
151 * 1 - Objects can be any size, and have any compatible fencing (X Y, or none
152 * as set via i915_gem_set_tiling() [DRM_I915_GEM_SET_TILING]). If the
153 * object is too large for the available space (or simply too large
154 * for the mappable aperture!), a view is created instead and faulted
155 * into userspace. (This view is aligned and sized appropriately for
156 * fenced access.)
157 *
158 * 2 - Recognise WC as a separate cache domain so that we can flush the
159 * delayed writes via GTT before performing direct access via WC.
160 *
161 * 3 - Remove implicit set-domain(GTT) and synchronisation on initial
162 * pagefault; swapin remains transparent.
163 *
164 * 4 - Support multiple fault handlers per object depending on object's
165 * backing storage (a.k.a. MMAP_OFFSET).
166 *
167 * 5 - Support multiple partial mmaps(mmap part of BO + unmap a offset, multiple
168 * times with different size and offset).
169 *
170 * Restrictions:
171 *
172 * * snoopable objects cannot be accessed via the GTT. It can cause machine
173 * hangs on some architectures, corruption on others. An attempt to service
174 * a GTT page fault from a snoopable object will generate a SIGBUS.
175 *
176 * * the object must be able to fit into RAM (physical memory, though no
177 * limited to the mappable aperture).
178 *
179 *
180 * Caveats:
181 *
182 * * a new GTT page fault will synchronize rendering from the GPU and flush
183 * all data to system memory. Subsequent access will not be synchronized.
184 *
185 * * all mappings are revoked on runtime device suspend.
186 *
187 * * there are only 8, 16 or 32 fence registers to share between all users
188 * (older machines require fence register for display and blitter access
189 * as well). Contention of the fence registers will cause the previous users
190 * to be unmapped and any new access will generate new page faults.
191 *
192 * * running out of memory while servicing a fault may generate a SIGBUS,
193 * rather than the expected SIGSEGV.
194 */
i915_gem_mmap_gtt_version(void)195 int i915_gem_mmap_gtt_version(void)
196 {
197 return 5;
198 }
199
200 static inline struct i915_gtt_view
compute_partial_view(const struct drm_i915_gem_object * obj,pgoff_t page_offset,unsigned int chunk)201 compute_partial_view(const struct drm_i915_gem_object *obj,
202 pgoff_t page_offset,
203 unsigned int chunk)
204 {
205 struct i915_gtt_view view;
206
207 if (i915_gem_object_is_tiled(obj))
208 chunk = roundup(chunk, tile_row_pages(obj) ?: 1);
209
210 view.type = I915_GTT_VIEW_PARTIAL;
211 view.partial.offset = rounddown(page_offset, chunk);
212 view.partial.size =
213 min_t(unsigned int, chunk,
214 (obj->base.size >> PAGE_SHIFT) - view.partial.offset);
215
216 /* If the partial covers the entire object, just create a normal VMA. */
217 if (chunk >= obj->base.size >> PAGE_SHIFT)
218 view.type = I915_GTT_VIEW_NORMAL;
219
220 return view;
221 }
222
i915_error_to_vmf_fault(int err)223 static vm_fault_t i915_error_to_vmf_fault(int err)
224 {
225 switch (err) {
226 default:
227 WARN_ONCE(err, "unhandled error in %s: %i\n", __func__, err);
228 fallthrough;
229 case -EIO: /* shmemfs failure from swap device */
230 case -EFAULT: /* purged object */
231 case -ENODEV: /* bad object, how did you get here! */
232 case -ENXIO: /* unable to access backing store (on device) */
233 return VM_FAULT_SIGBUS;
234
235 case -ENOMEM: /* our allocation failure */
236 return VM_FAULT_OOM;
237
238 case 0:
239 case -EAGAIN:
240 case -ENOSPC: /* transient failure to evict? */
241 case -ENOBUFS: /* temporarily out of fences? */
242 case -ERESTARTSYS:
243 case -EINTR:
244 case -EBUSY:
245 /*
246 * EBUSY is ok: this just means that another thread
247 * already did the job.
248 */
249 return VM_FAULT_NOPAGE;
250 }
251 }
252
vm_fault_cpu(struct vm_fault * vmf)253 static vm_fault_t vm_fault_cpu(struct vm_fault *vmf)
254 {
255 struct vm_area_struct *area = vmf->vma;
256 struct i915_mmap_offset *mmo = area->vm_private_data;
257 struct drm_i915_gem_object *obj = mmo->obj;
258 unsigned long obj_offset;
259 resource_size_t iomap;
260 int err;
261
262 /* Sanity check that we allow writing into this object */
263 if (unlikely(i915_gem_object_is_readonly(obj) &&
264 area->vm_flags & VM_WRITE))
265 return VM_FAULT_SIGBUS;
266
267 if (i915_gem_object_lock_interruptible(obj, NULL))
268 return VM_FAULT_NOPAGE;
269
270 err = i915_gem_object_pin_pages(obj);
271 if (err)
272 goto out;
273
274 iomap = -1;
275 if (!i915_gem_object_has_struct_page(obj)) {
276 iomap = obj->mm.region->iomap.base;
277 iomap -= obj->mm.region->region.start;
278 }
279
280 obj_offset = area->vm_pgoff - drm_vma_node_start(&mmo->vma_node);
281 /* PTEs are revoked in obj->ops->put_pages() */
282 err = remap_io_sg(area,
283 area->vm_start, area->vm_end - area->vm_start,
284 obj->mm.pages->sgl, obj_offset, iomap);
285
286 if (area->vm_flags & VM_WRITE) {
287 GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
288 obj->mm.dirty = true;
289 }
290
291 i915_gem_object_unpin_pages(obj);
292
293 out:
294 i915_gem_object_unlock(obj);
295 return i915_error_to_vmf_fault(err);
296 }
297
set_address_limits(struct vm_area_struct * area,struct i915_vma * vma,unsigned long obj_offset,resource_size_t gmadr_start,unsigned long * start_vaddr,unsigned long * end_vaddr,unsigned long * pfn)298 static void set_address_limits(struct vm_area_struct *area,
299 struct i915_vma *vma,
300 unsigned long obj_offset,
301 resource_size_t gmadr_start,
302 unsigned long *start_vaddr,
303 unsigned long *end_vaddr,
304 unsigned long *pfn)
305 {
306 unsigned long vm_start, vm_end, vma_size; /* user's memory parameters */
307 long start, end; /* memory boundaries */
308
309 /*
310 * Let's move into the ">> PAGE_SHIFT"
311 * domain to be sure not to lose bits
312 */
313 vm_start = area->vm_start >> PAGE_SHIFT;
314 vm_end = area->vm_end >> PAGE_SHIFT;
315 vma_size = vma->size >> PAGE_SHIFT;
316
317 /*
318 * Calculate the memory boundaries by considering the offset
319 * provided by the user during memory mapping and the offset
320 * provided for the partial mapping.
321 */
322 start = vm_start;
323 start -= obj_offset;
324 start += vma->gtt_view.partial.offset;
325 end = start + vma_size;
326
327 start = max_t(long, start, vm_start);
328 end = min_t(long, end, vm_end);
329
330 /* Let's move back into the "<< PAGE_SHIFT" domain */
331 *start_vaddr = (unsigned long)start << PAGE_SHIFT;
332 *end_vaddr = (unsigned long)end << PAGE_SHIFT;
333
334 *pfn = (gmadr_start + i915_ggtt_offset(vma)) >> PAGE_SHIFT;
335 *pfn += (*start_vaddr - area->vm_start) >> PAGE_SHIFT;
336 *pfn += obj_offset - vma->gtt_view.partial.offset;
337 }
338
vm_fault_gtt(struct vm_fault * vmf)339 static vm_fault_t vm_fault_gtt(struct vm_fault *vmf)
340 {
341 #define MIN_CHUNK_PAGES (SZ_1M >> PAGE_SHIFT)
342 struct vm_area_struct *area = vmf->vma;
343 struct i915_mmap_offset *mmo = area->vm_private_data;
344 struct drm_i915_gem_object *obj = mmo->obj;
345 struct drm_device *dev = obj->base.dev;
346 struct drm_i915_private *i915 = to_i915(dev);
347 struct intel_runtime_pm *rpm = &i915->runtime_pm;
348 struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
349 bool write = area->vm_flags & VM_WRITE;
350 struct i915_gem_ww_ctx ww;
351 unsigned long obj_offset;
352 unsigned long start, end; /* memory boundaries */
353 intel_wakeref_t wakeref;
354 struct i915_vma *vma;
355 pgoff_t page_offset;
356 unsigned long pfn;
357 int srcu;
358 int ret;
359
360 obj_offset = area->vm_pgoff - drm_vma_node_start(&mmo->vma_node);
361 page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
362 page_offset += obj_offset;
363
364 trace_i915_gem_object_fault(obj, page_offset, true, write);
365
366 wakeref = intel_runtime_pm_get(rpm);
367
368 i915_gem_ww_ctx_init(&ww, true);
369 retry:
370 ret = i915_gem_object_lock(obj, &ww);
371 if (ret)
372 goto err_rpm;
373
374 /* Sanity check that we allow writing into this object */
375 if (i915_gem_object_is_readonly(obj) && write) {
376 ret = -EFAULT;
377 goto err_rpm;
378 }
379
380 ret = i915_gem_object_pin_pages(obj);
381 if (ret)
382 goto err_rpm;
383
384 ret = intel_gt_reset_lock_interruptible(ggtt->vm.gt, &srcu);
385 if (ret)
386 goto err_pages;
387
388 /* Now pin it into the GTT as needed */
389 vma = i915_gem_object_ggtt_pin_ww(obj, &ww, NULL, 0, 0,
390 PIN_MAPPABLE |
391 PIN_NONBLOCK /* NOWARN */ |
392 PIN_NOEVICT);
393 if (IS_ERR(vma) && vma != ERR_PTR(-EDEADLK)) {
394 /* Use a partial view if it is bigger than available space */
395 struct i915_gtt_view view =
396 compute_partial_view(obj, page_offset, MIN_CHUNK_PAGES);
397 unsigned int flags;
398
399 flags = PIN_MAPPABLE | PIN_NOSEARCH;
400 if (view.type == I915_GTT_VIEW_NORMAL)
401 flags |= PIN_NONBLOCK; /* avoid warnings for pinned */
402
403 /*
404 * Userspace is now writing through an untracked VMA, abandon
405 * all hope that the hardware is able to track future writes.
406 */
407
408 vma = i915_gem_object_ggtt_pin_ww(obj, &ww, &view, 0, 0, flags);
409 if (IS_ERR(vma) && vma != ERR_PTR(-EDEADLK)) {
410 flags = PIN_MAPPABLE;
411 view.type = I915_GTT_VIEW_PARTIAL;
412 vma = i915_gem_object_ggtt_pin_ww(obj, &ww, &view, 0, 0, flags);
413 }
414
415 /*
416 * The entire mappable GGTT is pinned? Unexpected!
417 * Try to evict the object we locked too, as normally we skip it
418 * due to lack of short term pinning inside execbuf.
419 */
420 if (vma == ERR_PTR(-ENOSPC)) {
421 ret = mutex_lock_interruptible(&ggtt->vm.mutex);
422 if (!ret) {
423 ret = i915_gem_evict_vm(&ggtt->vm, &ww, NULL);
424 mutex_unlock(&ggtt->vm.mutex);
425 }
426 if (ret)
427 goto err_reset;
428 vma = i915_gem_object_ggtt_pin_ww(obj, &ww, &view, 0, 0, flags);
429 }
430 }
431 if (IS_ERR(vma)) {
432 ret = PTR_ERR(vma);
433 goto err_reset;
434 }
435
436 /* Access to snoopable pages through the GTT is incoherent. */
437 /*
438 * For objects created by userspace through GEM_CREATE with pat_index
439 * set by set_pat extension, coherency is managed by userspace, make
440 * sure we don't fail handling the vm fault by calling
441 * i915_gem_object_has_cache_level() which always return true for such
442 * objects. Otherwise this helper function would fall back to checking
443 * whether the object is un-cached.
444 */
445 if (!(i915_gem_object_has_cache_level(obj, I915_CACHE_NONE) ||
446 HAS_LLC(i915))) {
447 ret = -EFAULT;
448 goto err_unpin;
449 }
450
451 ret = i915_vma_pin_fence(vma);
452 if (ret)
453 goto err_unpin;
454
455 /*
456 * Dump all the necessary parameters in this function to perform the
457 * arithmetic calculation for the virtual address start and end and
458 * the PFN (Page Frame Number).
459 */
460 set_address_limits(area, vma, obj_offset, ggtt->gmadr.start,
461 &start, &end, &pfn);
462
463 /* Finally, remap it using the new GTT offset */
464 ret = remap_io_mapping(area, start, pfn, end - start, &ggtt->iomap);
465 if (ret)
466 goto err_fence;
467
468 assert_rpm_wakelock_held(rpm);
469
470 /* Mark as being mmapped into userspace for later revocation */
471 mutex_lock(&to_gt(i915)->ggtt->vm.mutex);
472 if (!i915_vma_set_userfault(vma) && !obj->userfault_count++)
473 list_add(&obj->userfault_link, &to_gt(i915)->ggtt->userfault_list);
474 mutex_unlock(&to_gt(i915)->ggtt->vm.mutex);
475
476 /* Track the mmo associated with the fenced vma */
477 vma->mmo = mmo;
478
479 if (CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND)
480 intel_wakeref_auto(&i915->runtime_pm.userfault_wakeref,
481 msecs_to_jiffies_timeout(CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND));
482
483 if (write) {
484 GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
485 i915_vma_set_ggtt_write(vma);
486 obj->mm.dirty = true;
487 }
488
489 err_fence:
490 i915_vma_unpin_fence(vma);
491 err_unpin:
492 __i915_vma_unpin(vma);
493 err_reset:
494 intel_gt_reset_unlock(ggtt->vm.gt, srcu);
495 err_pages:
496 i915_gem_object_unpin_pages(obj);
497 err_rpm:
498 if (ret == -EDEADLK) {
499 ret = i915_gem_ww_ctx_backoff(&ww);
500 if (!ret)
501 goto retry;
502 }
503 i915_gem_ww_ctx_fini(&ww);
504 intel_runtime_pm_put(rpm, wakeref);
505 return i915_error_to_vmf_fault(ret);
506 }
507
508 static int
vm_access(struct vm_area_struct * area,unsigned long addr,void * buf,int len,int write)509 vm_access(struct vm_area_struct *area, unsigned long addr,
510 void *buf, int len, int write)
511 {
512 struct i915_mmap_offset *mmo = area->vm_private_data;
513 struct drm_i915_gem_object *obj = mmo->obj;
514 struct i915_gem_ww_ctx ww;
515 void *vaddr;
516 int err = 0;
517
518 if (i915_gem_object_is_readonly(obj) && write)
519 return -EACCES;
520
521 addr -= area->vm_start;
522 if (range_overflows_t(u64, addr, len, obj->base.size))
523 return -EINVAL;
524
525 i915_gem_ww_ctx_init(&ww, true);
526 retry:
527 err = i915_gem_object_lock(obj, &ww);
528 if (err)
529 goto out;
530
531 /* As this is primarily for debugging, let's focus on simplicity */
532 vaddr = i915_gem_object_pin_map(obj, I915_MAP_FORCE_WC);
533 if (IS_ERR(vaddr)) {
534 err = PTR_ERR(vaddr);
535 goto out;
536 }
537
538 if (write) {
539 memcpy(vaddr + addr, buf, len);
540 __i915_gem_object_flush_map(obj, addr, len);
541 } else {
542 memcpy(buf, vaddr + addr, len);
543 }
544
545 i915_gem_object_unpin_map(obj);
546 out:
547 if (err == -EDEADLK) {
548 err = i915_gem_ww_ctx_backoff(&ww);
549 if (!err)
550 goto retry;
551 }
552 i915_gem_ww_ctx_fini(&ww);
553
554 if (err)
555 return err;
556
557 return len;
558 }
559
__i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object * obj)560 void __i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj)
561 {
562 struct i915_vma *vma;
563
564 GEM_BUG_ON(!obj->userfault_count);
565
566 for_each_ggtt_vma(vma, obj)
567 i915_vma_revoke_mmap(vma);
568
569 GEM_BUG_ON(obj->userfault_count);
570 }
571
572 /*
573 * It is vital that we remove the page mapping if we have mapped a tiled
574 * object through the GTT and then lose the fence register due to
575 * resource pressure. Similarly if the object has been moved out of the
576 * aperture, than pages mapped into userspace must be revoked. Removing the
577 * mapping will then trigger a page fault on the next user access, allowing
578 * fixup by vm_fault_gtt().
579 */
i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object * obj)580 void i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj)
581 {
582 struct drm_i915_private *i915 = to_i915(obj->base.dev);
583 intel_wakeref_t wakeref;
584
585 /*
586 * Serialisation between user GTT access and our code depends upon
587 * revoking the CPU's PTE whilst the mutex is held. The next user
588 * pagefault then has to wait until we release the mutex.
589 *
590 * Note that RPM complicates somewhat by adding an additional
591 * requirement that operations to the GGTT be made holding the RPM
592 * wakeref.
593 */
594 wakeref = intel_runtime_pm_get(&i915->runtime_pm);
595 mutex_lock(&to_gt(i915)->ggtt->vm.mutex);
596
597 if (!obj->userfault_count)
598 goto out;
599
600 __i915_gem_object_release_mmap_gtt(obj);
601
602 /*
603 * Ensure that the CPU's PTE are revoked and there are not outstanding
604 * memory transactions from userspace before we return. The TLB
605 * flushing implied above by changing the PTE above *should* be
606 * sufficient, an extra barrier here just provides us with a bit
607 * of paranoid documentation about our requirement to serialise
608 * memory writes before touching registers / GSM.
609 */
610 wmb();
611
612 out:
613 mutex_unlock(&to_gt(i915)->ggtt->vm.mutex);
614 intel_runtime_pm_put(&i915->runtime_pm, wakeref);
615 }
616
i915_gem_object_runtime_pm_release_mmap_offset(struct drm_i915_gem_object * obj)617 void i915_gem_object_runtime_pm_release_mmap_offset(struct drm_i915_gem_object *obj)
618 {
619 struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
620 struct ttm_device *bdev = bo->bdev;
621
622 drm_vma_node_unmap(&bo->base.vma_node, bdev->dev_mapping);
623
624 /*
625 * We have exclusive access here via runtime suspend. All other callers
626 * must first grab the rpm wakeref.
627 */
628 GEM_BUG_ON(!obj->userfault_count);
629 list_del(&obj->userfault_link);
630 obj->userfault_count = 0;
631 }
632
i915_gem_object_release_mmap_offset(struct drm_i915_gem_object * obj)633 void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj)
634 {
635 struct i915_mmap_offset *mmo, *mn;
636
637 if (obj->ops->unmap_virtual)
638 obj->ops->unmap_virtual(obj);
639
640 spin_lock(&obj->mmo.lock);
641 rbtree_postorder_for_each_entry_safe(mmo, mn,
642 &obj->mmo.offsets, offset) {
643 /*
644 * vma_node_unmap for GTT mmaps handled already in
645 * __i915_gem_object_release_mmap_gtt
646 */
647 if (mmo->mmap_type == I915_MMAP_TYPE_GTT)
648 continue;
649
650 spin_unlock(&obj->mmo.lock);
651 drm_vma_node_unmap(&mmo->vma_node,
652 obj->base.dev->anon_inode->i_mapping);
653 spin_lock(&obj->mmo.lock);
654 }
655 spin_unlock(&obj->mmo.lock);
656 }
657
658 static struct i915_mmap_offset *
lookup_mmo(struct drm_i915_gem_object * obj,enum i915_mmap_type mmap_type)659 lookup_mmo(struct drm_i915_gem_object *obj,
660 enum i915_mmap_type mmap_type)
661 {
662 struct rb_node *rb;
663
664 spin_lock(&obj->mmo.lock);
665 rb = obj->mmo.offsets.rb_node;
666 while (rb) {
667 struct i915_mmap_offset *mmo =
668 rb_entry(rb, typeof(*mmo), offset);
669
670 if (mmo->mmap_type == mmap_type) {
671 spin_unlock(&obj->mmo.lock);
672 return mmo;
673 }
674
675 if (mmo->mmap_type < mmap_type)
676 rb = rb->rb_right;
677 else
678 rb = rb->rb_left;
679 }
680 spin_unlock(&obj->mmo.lock);
681
682 return NULL;
683 }
684
685 static struct i915_mmap_offset *
insert_mmo(struct drm_i915_gem_object * obj,struct i915_mmap_offset * mmo)686 insert_mmo(struct drm_i915_gem_object *obj, struct i915_mmap_offset *mmo)
687 {
688 struct rb_node *rb, **p;
689
690 spin_lock(&obj->mmo.lock);
691 rb = NULL;
692 p = &obj->mmo.offsets.rb_node;
693 while (*p) {
694 struct i915_mmap_offset *pos;
695
696 rb = *p;
697 pos = rb_entry(rb, typeof(*pos), offset);
698
699 if (pos->mmap_type == mmo->mmap_type) {
700 spin_unlock(&obj->mmo.lock);
701 drm_vma_offset_remove(obj->base.dev->vma_offset_manager,
702 &mmo->vma_node);
703 kfree(mmo);
704 return pos;
705 }
706
707 if (pos->mmap_type < mmo->mmap_type)
708 p = &rb->rb_right;
709 else
710 p = &rb->rb_left;
711 }
712 rb_link_node(&mmo->offset, rb, p);
713 rb_insert_color(&mmo->offset, &obj->mmo.offsets);
714 spin_unlock(&obj->mmo.lock);
715
716 return mmo;
717 }
718
719 static struct i915_mmap_offset *
mmap_offset_attach(struct drm_i915_gem_object * obj,enum i915_mmap_type mmap_type,struct drm_file * file)720 mmap_offset_attach(struct drm_i915_gem_object *obj,
721 enum i915_mmap_type mmap_type,
722 struct drm_file *file)
723 {
724 struct drm_i915_private *i915 = to_i915(obj->base.dev);
725 struct i915_mmap_offset *mmo;
726 int err;
727
728 GEM_BUG_ON(obj->ops->mmap_offset || obj->ops->mmap_ops);
729
730 mmo = lookup_mmo(obj, mmap_type);
731 if (mmo)
732 goto out;
733
734 mmo = kmalloc(sizeof(*mmo), GFP_KERNEL);
735 if (!mmo)
736 return ERR_PTR(-ENOMEM);
737
738 mmo->obj = obj;
739 mmo->mmap_type = mmap_type;
740 drm_vma_node_reset(&mmo->vma_node);
741
742 err = drm_vma_offset_add(obj->base.dev->vma_offset_manager,
743 &mmo->vma_node, obj->base.size / PAGE_SIZE);
744 if (likely(!err))
745 goto insert;
746
747 /* Attempt to reap some mmap space from dead objects */
748 err = intel_gt_retire_requests_timeout(to_gt(i915), MAX_SCHEDULE_TIMEOUT,
749 NULL);
750 if (err)
751 goto err;
752
753 i915_gem_drain_freed_objects(i915);
754 err = drm_vma_offset_add(obj->base.dev->vma_offset_manager,
755 &mmo->vma_node, obj->base.size / PAGE_SIZE);
756 if (err)
757 goto err;
758
759 insert:
760 mmo = insert_mmo(obj, mmo);
761 GEM_BUG_ON(lookup_mmo(obj, mmap_type) != mmo);
762 out:
763 if (file)
764 drm_vma_node_allow_once(&mmo->vma_node, file);
765 return mmo;
766
767 err:
768 kfree(mmo);
769 return ERR_PTR(err);
770 }
771
772 static int
__assign_mmap_offset(struct drm_i915_gem_object * obj,enum i915_mmap_type mmap_type,u64 * offset,struct drm_file * file)773 __assign_mmap_offset(struct drm_i915_gem_object *obj,
774 enum i915_mmap_type mmap_type,
775 u64 *offset, struct drm_file *file)
776 {
777 struct i915_mmap_offset *mmo;
778
779 if (i915_gem_object_never_mmap(obj))
780 return -ENODEV;
781
782 if (obj->ops->mmap_offset) {
783 if (mmap_type != I915_MMAP_TYPE_FIXED)
784 return -ENODEV;
785
786 *offset = obj->ops->mmap_offset(obj);
787 return 0;
788 }
789
790 if (mmap_type == I915_MMAP_TYPE_FIXED)
791 return -ENODEV;
792
793 if (mmap_type != I915_MMAP_TYPE_GTT &&
794 !i915_gem_object_has_struct_page(obj) &&
795 !i915_gem_object_has_iomem(obj))
796 return -ENODEV;
797
798 mmo = mmap_offset_attach(obj, mmap_type, file);
799 if (IS_ERR(mmo))
800 return PTR_ERR(mmo);
801
802 *offset = drm_vma_node_offset_addr(&mmo->vma_node);
803 return 0;
804 }
805
806 static int
__assign_mmap_offset_handle(struct drm_file * file,u32 handle,enum i915_mmap_type mmap_type,u64 * offset)807 __assign_mmap_offset_handle(struct drm_file *file,
808 u32 handle,
809 enum i915_mmap_type mmap_type,
810 u64 *offset)
811 {
812 struct drm_i915_gem_object *obj;
813 int err;
814
815 obj = i915_gem_object_lookup(file, handle);
816 if (!obj)
817 return -ENOENT;
818
819 err = i915_gem_object_lock_interruptible(obj, NULL);
820 if (err)
821 goto out_put;
822 err = __assign_mmap_offset(obj, mmap_type, offset, file);
823 i915_gem_object_unlock(obj);
824 out_put:
825 i915_gem_object_put(obj);
826 return err;
827 }
828
829 int
i915_gem_dumb_mmap_offset(struct drm_file * file,struct drm_device * dev,u32 handle,u64 * offset)830 i915_gem_dumb_mmap_offset(struct drm_file *file,
831 struct drm_device *dev,
832 u32 handle,
833 u64 *offset)
834 {
835 struct drm_i915_private *i915 = to_i915(dev);
836 enum i915_mmap_type mmap_type;
837
838 if (HAS_LMEM(to_i915(dev)))
839 mmap_type = I915_MMAP_TYPE_FIXED;
840 else if (pat_enabled())
841 mmap_type = I915_MMAP_TYPE_WC;
842 else if (!i915_ggtt_has_aperture(to_gt(i915)->ggtt))
843 return -ENODEV;
844 else
845 mmap_type = I915_MMAP_TYPE_GTT;
846
847 return __assign_mmap_offset_handle(file, handle, mmap_type, offset);
848 }
849
850 /**
851 * i915_gem_mmap_offset_ioctl - prepare an object for GTT mmap'ing
852 * @dev: DRM device
853 * @data: GTT mapping ioctl data
854 * @file: GEM object info
855 *
856 * Simply returns the fake offset to userspace so it can mmap it.
857 * The mmap call will end up in drm_gem_mmap(), which will set things
858 * up so we can get faults in the handler above.
859 *
860 * The fault handler will take care of binding the object into the GTT
861 * (since it may have been evicted to make room for something), allocating
862 * a fence register, and mapping the appropriate aperture address into
863 * userspace.
864 */
865 int
i915_gem_mmap_offset_ioctl(struct drm_device * dev,void * data,struct drm_file * file)866 i915_gem_mmap_offset_ioctl(struct drm_device *dev, void *data,
867 struct drm_file *file)
868 {
869 struct drm_i915_private *i915 = to_i915(dev);
870 struct drm_i915_gem_mmap_offset *args = data;
871 enum i915_mmap_type type;
872 int err;
873
874 /*
875 * Historically we failed to check args.pad and args.offset
876 * and so we cannot use those fields for user input and we cannot
877 * add -EINVAL for them as the ABI is fixed, i.e. old userspace
878 * may be feeding in garbage in those fields.
879 *
880 * if (args->pad) return -EINVAL; is verbotten!
881 */
882
883 err = i915_user_extensions(u64_to_user_ptr(args->extensions),
884 NULL, 0, NULL);
885 if (err)
886 return err;
887
888 switch (args->flags) {
889 case I915_MMAP_OFFSET_GTT:
890 if (!i915_ggtt_has_aperture(to_gt(i915)->ggtt))
891 return -ENODEV;
892 type = I915_MMAP_TYPE_GTT;
893 break;
894
895 case I915_MMAP_OFFSET_WC:
896 if (!pat_enabled())
897 return -ENODEV;
898 type = I915_MMAP_TYPE_WC;
899 break;
900
901 case I915_MMAP_OFFSET_WB:
902 type = I915_MMAP_TYPE_WB;
903 break;
904
905 case I915_MMAP_OFFSET_UC:
906 if (!pat_enabled())
907 return -ENODEV;
908 type = I915_MMAP_TYPE_UC;
909 break;
910
911 case I915_MMAP_OFFSET_FIXED:
912 type = I915_MMAP_TYPE_FIXED;
913 break;
914
915 default:
916 return -EINVAL;
917 }
918
919 return __assign_mmap_offset_handle(file, args->handle, type, &args->offset);
920 }
921
vm_open(struct vm_area_struct * vma)922 static void vm_open(struct vm_area_struct *vma)
923 {
924 struct i915_mmap_offset *mmo = vma->vm_private_data;
925 struct drm_i915_gem_object *obj = mmo->obj;
926
927 GEM_BUG_ON(!obj);
928 i915_gem_object_get(obj);
929 }
930
vm_close(struct vm_area_struct * vma)931 static void vm_close(struct vm_area_struct *vma)
932 {
933 struct i915_mmap_offset *mmo = vma->vm_private_data;
934 struct drm_i915_gem_object *obj = mmo->obj;
935
936 GEM_BUG_ON(!obj);
937 i915_gem_object_put(obj);
938 }
939
940 static const struct vm_operations_struct vm_ops_gtt = {
941 .fault = vm_fault_gtt,
942 .access = vm_access,
943 .open = vm_open,
944 .close = vm_close,
945 };
946
947 static const struct vm_operations_struct vm_ops_cpu = {
948 .fault = vm_fault_cpu,
949 .access = vm_access,
950 .open = vm_open,
951 .close = vm_close,
952 };
953
singleton_release(struct inode * inode,struct file * file)954 static int singleton_release(struct inode *inode, struct file *file)
955 {
956 struct drm_i915_private *i915 = file->private_data;
957
958 cmpxchg(&i915->gem.mmap_singleton, file, NULL);
959 drm_dev_put(&i915->drm);
960
961 return 0;
962 }
963
964 static const struct file_operations singleton_fops = {
965 .owner = THIS_MODULE,
966 .release = singleton_release,
967 };
968
mmap_singleton(struct drm_i915_private * i915)969 static struct file *mmap_singleton(struct drm_i915_private *i915)
970 {
971 struct file *file;
972
973 file = get_file_active(&i915->gem.mmap_singleton);
974 if (file)
975 return file;
976
977 file = anon_inode_getfile("i915.gem", &singleton_fops, i915, O_RDWR);
978 if (IS_ERR(file))
979 return file;
980
981 /* Everyone shares a single global address space */
982 file->f_mapping = i915->drm.anon_inode->i_mapping;
983
984 smp_store_mb(i915->gem.mmap_singleton, file);
985 drm_dev_get(&i915->drm);
986
987 return file;
988 }
989
990 static int
i915_gem_object_mmap(struct drm_i915_gem_object * obj,struct i915_mmap_offset * mmo,struct vm_area_struct * vma)991 i915_gem_object_mmap(struct drm_i915_gem_object *obj,
992 struct i915_mmap_offset *mmo,
993 struct vm_area_struct *vma)
994 {
995 struct drm_i915_private *i915 = to_i915(obj->base.dev);
996 struct drm_device *dev = &i915->drm;
997 struct file *anon;
998
999 if (i915_gem_object_is_readonly(obj)) {
1000 if (vma->vm_flags & VM_WRITE) {
1001 i915_gem_object_put(obj);
1002 return -EINVAL;
1003 }
1004 vm_flags_clear(vma, VM_MAYWRITE);
1005 }
1006
1007 anon = mmap_singleton(to_i915(dev));
1008 if (IS_ERR(anon)) {
1009 i915_gem_object_put(obj);
1010 return PTR_ERR(anon);
1011 }
1012
1013 vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO);
1014
1015 /*
1016 * We keep the ref on mmo->obj, not vm_file, but we require
1017 * vma->vm_file->f_mapping, see vma_link(), for later revocation.
1018 * Our userspace is accustomed to having per-file resource cleanup
1019 * (i.e. contexts, objects and requests) on their close(fd), which
1020 * requires avoiding extraneous references to their filp, hence why
1021 * we prefer to use an anonymous file for their mmaps.
1022 */
1023 vma_set_file(vma, anon);
1024 /* Drop the initial creation reference, the vma is now holding one. */
1025 fput(anon);
1026
1027 if (obj->ops->mmap_ops) {
1028 vma->vm_page_prot = pgprot_decrypted(vm_get_page_prot(vma->vm_flags));
1029 vma->vm_ops = obj->ops->mmap_ops;
1030 vma->vm_private_data = obj->base.vma_node.driver_private;
1031 return 0;
1032 }
1033
1034 vma->vm_private_data = mmo;
1035
1036 switch (mmo->mmap_type) {
1037 case I915_MMAP_TYPE_WC:
1038 vma->vm_page_prot =
1039 pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
1040 vma->vm_ops = &vm_ops_cpu;
1041 break;
1042
1043 case I915_MMAP_TYPE_FIXED:
1044 GEM_WARN_ON(1);
1045 fallthrough;
1046 case I915_MMAP_TYPE_WB:
1047 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
1048 vma->vm_ops = &vm_ops_cpu;
1049 break;
1050
1051 case I915_MMAP_TYPE_UC:
1052 vma->vm_page_prot =
1053 pgprot_noncached(vm_get_page_prot(vma->vm_flags));
1054 vma->vm_ops = &vm_ops_cpu;
1055 break;
1056
1057 case I915_MMAP_TYPE_GTT:
1058 vma->vm_page_prot =
1059 pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
1060 vma->vm_ops = &vm_ops_gtt;
1061 break;
1062 }
1063 vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
1064
1065 return 0;
1066 }
1067
1068 /*
1069 * This overcomes the limitation in drm_gem_mmap's assignment of a
1070 * drm_gem_object as the vma->vm_private_data. Since we need to
1071 * be able to resolve multiple mmap offsets which could be tied
1072 * to a single gem object.
1073 */
i915_gem_mmap(struct file * filp,struct vm_area_struct * vma)1074 int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
1075 {
1076 struct drm_vma_offset_node *node;
1077 struct drm_file *priv = filp->private_data;
1078 struct drm_device *dev = priv->minor->dev;
1079 struct drm_i915_gem_object *obj = NULL;
1080 struct i915_mmap_offset *mmo = NULL;
1081
1082 if (drm_dev_is_unplugged(dev))
1083 return -ENODEV;
1084
1085 rcu_read_lock();
1086 drm_vma_offset_lock_lookup(dev->vma_offset_manager);
1087 node = drm_vma_offset_lookup_locked(dev->vma_offset_manager,
1088 vma->vm_pgoff,
1089 vma_pages(vma));
1090 if (node && drm_vma_node_is_allowed(node, priv)) {
1091 /*
1092 * Skip 0-refcnted objects as it is in the process of being
1093 * destroyed and will be invalid when the vma manager lock
1094 * is released.
1095 */
1096 if (!node->driver_private) {
1097 mmo = container_of(node, struct i915_mmap_offset, vma_node);
1098 obj = i915_gem_object_get_rcu(mmo->obj);
1099
1100 GEM_BUG_ON(obj && obj->ops->mmap_ops);
1101 } else {
1102 obj = i915_gem_object_get_rcu
1103 (container_of(node, struct drm_i915_gem_object,
1104 base.vma_node));
1105
1106 GEM_BUG_ON(obj && !obj->ops->mmap_ops);
1107 }
1108 }
1109 drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
1110 rcu_read_unlock();
1111 if (!obj)
1112 return node ? -EACCES : -EINVAL;
1113
1114 return i915_gem_object_mmap(obj, mmo, vma);
1115 }
1116
i915_gem_fb_mmap(struct drm_i915_gem_object * obj,struct vm_area_struct * vma)1117 int i915_gem_fb_mmap(struct drm_i915_gem_object *obj, struct vm_area_struct *vma)
1118 {
1119 struct drm_i915_private *i915 = to_i915(obj->base.dev);
1120 struct drm_device *dev = &i915->drm;
1121 struct i915_mmap_offset *mmo = NULL;
1122 enum i915_mmap_type mmap_type;
1123 struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
1124
1125 if (drm_dev_is_unplugged(dev))
1126 return -ENODEV;
1127
1128 /* handle ttm object */
1129 if (obj->ops->mmap_ops) {
1130 /*
1131 * ttm fault handler, ttm_bo_vm_fault_reserved() uses fake offset
1132 * to calculate page offset so set that up.
1133 */
1134 vma->vm_pgoff += drm_vma_node_start(&obj->base.vma_node);
1135 } else {
1136 /* handle stolen and smem objects */
1137 mmap_type = i915_ggtt_has_aperture(ggtt) ? I915_MMAP_TYPE_GTT : I915_MMAP_TYPE_WC;
1138 mmo = mmap_offset_attach(obj, mmap_type, NULL);
1139 if (IS_ERR(mmo))
1140 return PTR_ERR(mmo);
1141
1142 vma->vm_pgoff += drm_vma_node_start(&mmo->vma_node);
1143 }
1144
1145 /*
1146 * When we install vm_ops for mmap we are too late for
1147 * the vm_ops->open() which increases the ref_count of
1148 * this obj and then it gets decreased by the vm_ops->close().
1149 * To balance this increase the obj ref_count here.
1150 */
1151 obj = i915_gem_object_get(obj);
1152 return i915_gem_object_mmap(obj, mmo, vma);
1153 }
1154
1155 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
1156 #include "selftests/i915_gem_mman.c"
1157 #endif
1158