1// SPDX-License-Identifier: MIT
2/*
3 * Copyright © 2008 Intel Corporation
4 */
5
6#include <linux/string.h>
7#include <linux/bitops.h>
8
9#include "i915_drv.h"
10#include "i915_gem.h"
11#include "i915_gem_ioctls.h"
12#include "i915_gem_mman.h"
13#include "i915_gem_object.h"
14#include "i915_gem_tiling.h"
15#include "i915_reg.h"
16
17/**
18 * DOC: buffer object tiling
19 *
20 * i915_gem_set_tiling_ioctl() and i915_gem_get_tiling_ioctl() is the userspace
21 * interface to declare fence register requirements.
22 *
23 * In principle GEM doesn't care at all about the internal data layout of an
24 * object, and hence it also doesn't care about tiling or swizzling. There's two
25 * exceptions:
26 *
27 * - For X and Y tiling the hardware provides detilers for CPU access, so called
28 * fences. Since there's only a limited amount of them the kernel must manage
29 * these, and therefore userspace must tell the kernel the object tiling if it
30 * wants to use fences for detiling.
31 * - On gen3 and gen4 platforms have a swizzling pattern for tiled objects which
32 * depends upon the physical page frame number. When swapping such objects the
33 * page frame number might change and the kernel must be able to fix this up
34 * and hence now the tiling. Note that on a subset of platforms with
35 * asymmetric memory channel population the swizzling pattern changes in an
36 * unknown way, and for those the kernel simply forbids swapping completely.
37 *
38 * Since neither of this applies for new tiling layouts on modern platforms like
39 * W, Ys and Yf tiling GEM only allows object tiling to be set to X or Y tiled.
40 * Anything else can be handled in userspace entirely without the kernel's
41 * involvement.
42 */
43
44/**
45 * i915_gem_fence_size - required global GTT size for a fence
46 * @i915: i915 device
47 * @size: object size
48 * @tiling: tiling mode
49 * @stride: tiling stride
50 *
51 * Return the required global GTT size for a fence (view of a tiled object),
52 * taking into account potential fence register mapping.
53 */
54u32 i915_gem_fence_size(struct drm_i915_private *i915,
55 u32 size, unsigned int tiling, unsigned int stride)
56{
57 u32 ggtt_size;
58
59 GEM_BUG_ON(!size);
60
61 if (tiling == I915_TILING_NONE)
62 return size;
63
64 GEM_BUG_ON(!stride);
65
66 if (GRAPHICS_VER(i915) >= 4) {
67 stride *= i915_gem_tile_height(tiling);
68 GEM_BUG_ON(!IS_ALIGNED(stride, I965_FENCE_PAGE));
69 return roundup(size, stride);
70 }
71
72 /* Previous chips need a power-of-two fence region when tiling */
73 if (GRAPHICS_VER(i915) == 3)
74 ggtt_size = 1024*1024;
75 else
76 ggtt_size = 512*1024;
77
78 while (ggtt_size < size)
79 ggtt_size <<= 1;
80
81 return ggtt_size;
82}
83
84/**
85 * i915_gem_fence_alignment - required global GTT alignment for a fence
86 * @i915: i915 device
87 * @size: object size
88 * @tiling: tiling mode
89 * @stride: tiling stride
90 *
91 * Return the required global GTT alignment for a fence (a view of a tiled
92 * object), taking into account potential fence register mapping.
93 */
94u32 i915_gem_fence_alignment(struct drm_i915_private *i915, u32 size,
95 unsigned int tiling, unsigned int stride)
96{
97 GEM_BUG_ON(!size);
98
99 /*
100 * Minimum alignment is 4k (GTT page size), but might be greater
101 * if a fence register is needed for the object.
102 */
103 if (tiling == I915_TILING_NONE)
104 return I915_GTT_MIN_ALIGNMENT;
105
106 if (GRAPHICS_VER(i915) >= 4)
107 return I965_FENCE_PAGE;
108
109 /*
110 * Previous chips need to be aligned to the size of the smallest
111 * fence register that can contain the object.
112 */
113 return i915_gem_fence_size(i915, size, tiling, stride);
114}
115
116/* Check pitch constraints for all chips & tiling formats */
117static bool
118i915_tiling_ok(struct drm_i915_gem_object *obj,
119 unsigned int tiling, unsigned int stride)
120{
121 struct drm_i915_private *i915 = to_i915(dev: obj->base.dev);
122 unsigned int tile_width;
123
124 /* Linear is always fine */
125 if (tiling == I915_TILING_NONE)
126 return true;
127
128 if (tiling > I915_TILING_LAST)
129 return false;
130
131 /* check maximum stride & object size */
132 /* i965+ stores the end address of the gtt mapping in the fence
133 * reg, so dont bother to check the size */
134 if (GRAPHICS_VER(i915) >= 7) {
135 if (stride / 128 > GEN7_FENCE_MAX_PITCH_VAL)
136 return false;
137 } else if (GRAPHICS_VER(i915) >= 4) {
138 if (stride / 128 > I965_FENCE_MAX_PITCH_VAL)
139 return false;
140 } else {
141 if (stride > 8192)
142 return false;
143
144 if (!is_power_of_2(n: stride))
145 return false;
146 }
147
148 if (tiling == I915_TILING_Y && HAS_128_BYTE_Y_TILING(i915))
149 tile_width = 128;
150 else if (GRAPHICS_VER(i915) == 2)
151 tile_width = 128;
152 else
153 tile_width = 512;
154
155 if (!stride || !IS_ALIGNED(stride, tile_width))
156 return false;
157
158 return true;
159}
160
161static bool i915_vma_fence_prepare(struct i915_vma *vma,
162 int tiling_mode, unsigned int stride)
163{
164 struct drm_i915_private *i915 = vma->vm->i915;
165 u32 size, alignment;
166
167 if (!i915_vma_is_map_and_fenceable(vma))
168 return true;
169
170 size = i915_gem_fence_size(i915, size: vma->size, tiling: tiling_mode, stride);
171 if (i915_vma_size(vma) < size)
172 return false;
173
174 alignment = i915_gem_fence_alignment(i915, size: vma->size, tiling: tiling_mode, stride);
175 if (!IS_ALIGNED(i915_ggtt_offset(vma), alignment))
176 return false;
177
178 return true;
179}
180
181/* Make the current GTT allocation valid for the change in tiling. */
182static int
183i915_gem_object_fence_prepare(struct drm_i915_gem_object *obj,
184 int tiling_mode, unsigned int stride)
185{
186 struct drm_i915_private *i915 = to_i915(dev: obj->base.dev);
187 struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
188 struct i915_vma *vma, *vn;
189 LIST_HEAD(unbind);
190 int ret = 0;
191
192 if (tiling_mode == I915_TILING_NONE)
193 return 0;
194
195 mutex_lock(&ggtt->vm.mutex);
196
197 spin_lock(lock: &obj->vma.lock);
198 for_each_ggtt_vma(vma, obj) {
199 GEM_BUG_ON(vma->vm != &ggtt->vm);
200
201 if (i915_vma_fence_prepare(vma, tiling_mode, stride))
202 continue;
203
204 list_move(list: &vma->vm_link, head: &unbind);
205 }
206 spin_unlock(lock: &obj->vma.lock);
207
208 list_for_each_entry_safe(vma, vn, &unbind, vm_link) {
209 ret = __i915_vma_unbind(vma);
210 if (ret) {
211 /* Restore the remaining vma on an error */
212 list_splice(list: &unbind, head: &ggtt->vm.bound_list);
213 break;
214 }
215 }
216
217 mutex_unlock(lock: &ggtt->vm.mutex);
218
219 return ret;
220}
221
222bool i915_gem_object_needs_bit17_swizzle(struct drm_i915_gem_object *obj)
223{
224 struct drm_i915_private *i915 = to_i915(dev: obj->base.dev);
225
226 return to_gt(i915)->ggtt->bit_6_swizzle_x == I915_BIT_6_SWIZZLE_9_10_17 &&
227 i915_gem_object_is_tiled(obj);
228}
229
230int
231i915_gem_object_set_tiling(struct drm_i915_gem_object *obj,
232 unsigned int tiling, unsigned int stride)
233{
234 struct drm_i915_private *i915 = to_i915(dev: obj->base.dev);
235 struct i915_vma *vma;
236 int err;
237
238 /* Make sure we don't cross-contaminate obj->tiling_and_stride */
239 BUILD_BUG_ON(I915_TILING_LAST & STRIDE_MASK);
240
241 GEM_BUG_ON(!i915_tiling_ok(obj, tiling, stride));
242 GEM_BUG_ON(!stride ^ (tiling == I915_TILING_NONE));
243
244 if ((tiling | stride) == obj->tiling_and_stride)
245 return 0;
246
247 if (i915_gem_object_is_framebuffer(obj))
248 return -EBUSY;
249
250 /* We need to rebind the object if its current allocation
251 * no longer meets the alignment restrictions for its new
252 * tiling mode. Otherwise we can just leave it alone, but
253 * need to ensure that any fence register is updated before
254 * the next fenced (either through the GTT or by the BLT unit
255 * on older GPUs) access.
256 *
257 * After updating the tiling parameters, we then flag whether
258 * we need to update an associated fence register. Note this
259 * has to also include the unfenced register the GPU uses
260 * whilst executing a fenced command for an untiled object.
261 */
262
263 i915_gem_object_lock(obj, NULL);
264 if (i915_gem_object_is_framebuffer(obj)) {
265 i915_gem_object_unlock(obj);
266 return -EBUSY;
267 }
268
269 err = i915_gem_object_fence_prepare(obj, tiling_mode: tiling, stride);
270 if (err) {
271 i915_gem_object_unlock(obj);
272 return err;
273 }
274
275 /* If the memory has unknown (i.e. varying) swizzling, we pin the
276 * pages to prevent them being swapped out and causing corruption
277 * due to the change in swizzling.
278 */
279 if (i915_gem_object_has_pages(obj) &&
280 obj->mm.madv == I915_MADV_WILLNEED &&
281 i915->gem_quirks & GEM_QUIRK_PIN_SWIZZLED_PAGES) {
282 if (tiling == I915_TILING_NONE) {
283 GEM_BUG_ON(!i915_gem_object_has_tiling_quirk(obj));
284 i915_gem_object_clear_tiling_quirk(obj);
285 i915_gem_object_make_shrinkable(obj);
286 }
287 if (!i915_gem_object_is_tiled(obj)) {
288 GEM_BUG_ON(i915_gem_object_has_tiling_quirk(obj));
289 i915_gem_object_make_unshrinkable(obj);
290 i915_gem_object_set_tiling_quirk(obj);
291 }
292 }
293
294 spin_lock(lock: &obj->vma.lock);
295 for_each_ggtt_vma(vma, obj) {
296 vma->fence_size =
297 i915_gem_fence_size(i915, size: vma->size, tiling, stride);
298 vma->fence_alignment =
299 i915_gem_fence_alignment(i915,
300 size: vma->size, tiling, stride);
301
302 if (vma->fence)
303 vma->fence->dirty = true;
304 }
305 spin_unlock(lock: &obj->vma.lock);
306
307 obj->tiling_and_stride = tiling | stride;
308
309 /* Try to preallocate memory required to save swizzling on put-pages */
310 if (i915_gem_object_needs_bit17_swizzle(obj)) {
311 if (!obj->bit_17) {
312 obj->bit_17 = bitmap_zalloc(nbits: obj->base.size >> PAGE_SHIFT,
313 GFP_KERNEL);
314 }
315 } else {
316 bitmap_free(bitmap: obj->bit_17);
317 obj->bit_17 = NULL;
318 }
319
320 i915_gem_object_unlock(obj);
321
322 /* Force the fence to be reacquired for GTT access */
323 i915_gem_object_release_mmap_gtt(obj);
324
325 return 0;
326}
327
328/**
329 * i915_gem_set_tiling_ioctl - IOCTL handler to set tiling mode
330 * @dev: DRM device
331 * @data: data pointer for the ioctl
332 * @file: DRM file for the ioctl call
333 *
334 * Sets the tiling mode of an object, returning the required swizzling of
335 * bit 6 of addresses in the object.
336 *
337 * Called by the user via ioctl.
338 *
339 * Returns:
340 * Zero on success, negative errno on failure.
341 */
342int
343i915_gem_set_tiling_ioctl(struct drm_device *dev, void *data,
344 struct drm_file *file)
345{
346 struct drm_i915_private *i915 = to_i915(dev);
347 struct drm_i915_gem_set_tiling *args = data;
348 struct drm_i915_gem_object *obj;
349 int err;
350
351 if (!to_gt(i915)->ggtt->num_fences)
352 return -EOPNOTSUPP;
353
354 obj = i915_gem_object_lookup(file, handle: args->handle);
355 if (!obj)
356 return -ENOENT;
357
358 /*
359 * The tiling mode of proxy objects is handled by its generator, and
360 * not allowed to be changed by userspace.
361 */
362 if (i915_gem_object_is_proxy(obj)) {
363 err = -ENXIO;
364 goto err;
365 }
366
367 if (!i915_tiling_ok(obj, tiling: args->tiling_mode, stride: args->stride)) {
368 err = -EINVAL;
369 goto err;
370 }
371
372 if (args->tiling_mode == I915_TILING_NONE) {
373 args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
374 args->stride = 0;
375 } else {
376 if (args->tiling_mode == I915_TILING_X)
377 args->swizzle_mode = to_gt(i915)->ggtt->bit_6_swizzle_x;
378 else
379 args->swizzle_mode = to_gt(i915)->ggtt->bit_6_swizzle_y;
380
381 /* Hide bit 17 swizzling from the user. This prevents old Mesa
382 * from aborting the application on sw fallbacks to bit 17,
383 * and we use the pread/pwrite bit17 paths to swizzle for it.
384 * If there was a user that was relying on the swizzle
385 * information for drm_intel_bo_map()ed reads/writes this would
386 * break it, but we don't have any of those.
387 */
388 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
389 args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
390 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
391 args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;
392
393 /* If we can't handle the swizzling, make it untiled. */
394 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_UNKNOWN) {
395 args->tiling_mode = I915_TILING_NONE;
396 args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
397 args->stride = 0;
398 }
399 }
400
401 err = i915_gem_object_set_tiling(obj, tiling: args->tiling_mode, stride: args->stride);
402
403 /* We have to maintain this existing ABI... */
404 args->stride = i915_gem_object_get_stride(obj);
405 args->tiling_mode = i915_gem_object_get_tiling(obj);
406
407err:
408 i915_gem_object_put(obj);
409 return err;
410}
411
412/**
413 * i915_gem_get_tiling_ioctl - IOCTL handler to get tiling mode
414 * @dev: DRM device
415 * @data: data pointer for the ioctl
416 * @file: DRM file for the ioctl call
417 *
418 * Returns the current tiling mode and required bit 6 swizzling for the object.
419 *
420 * Called by the user via ioctl.
421 *
422 * Returns:
423 * Zero on success, negative errno on failure.
424 */
425int
426i915_gem_get_tiling_ioctl(struct drm_device *dev, void *data,
427 struct drm_file *file)
428{
429 struct drm_i915_gem_get_tiling *args = data;
430 struct drm_i915_private *i915 = to_i915(dev);
431 struct drm_i915_gem_object *obj;
432 int err = -ENOENT;
433
434 if (!to_gt(i915)->ggtt->num_fences)
435 return -EOPNOTSUPP;
436
437 rcu_read_lock();
438 obj = i915_gem_object_lookup_rcu(file, handle: args->handle);
439 if (obj) {
440 args->tiling_mode =
441 READ_ONCE(obj->tiling_and_stride) & TILING_MASK;
442 err = 0;
443 }
444 rcu_read_unlock();
445 if (unlikely(err))
446 return err;
447
448 switch (args->tiling_mode) {
449 case I915_TILING_X:
450 args->swizzle_mode = to_gt(i915)->ggtt->bit_6_swizzle_x;
451 break;
452 case I915_TILING_Y:
453 args->swizzle_mode = to_gt(i915)->ggtt->bit_6_swizzle_y;
454 break;
455 default:
456 case I915_TILING_NONE:
457 args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
458 break;
459 }
460
461 /* Hide bit 17 from the user -- see comment in i915_gem_set_tiling */
462 if (i915->gem_quirks & GEM_QUIRK_PIN_SWIZZLED_PAGES)
463 args->phys_swizzle_mode = I915_BIT_6_SWIZZLE_UNKNOWN;
464 else
465 args->phys_swizzle_mode = args->swizzle_mode;
466 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
467 args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
468 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
469 args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;
470
471 return 0;
472}
473

source code of linux/drivers/gpu/drm/i915/gem/i915_gem_tiling.c