1 /*
2  * Copyright (c) 2005 Topspin Communications.  All rights reserved.
3  * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
4  * Copyright (c) 2013 Cisco Systems.  All rights reserved.
5  *
6  * This software is available to you under a choice of one of two
7  * licenses.  You may choose to be licensed under the terms of the GNU
8  * General Public License (GPL) Version 2, available from the file
9  * COPYING in the main directory of this source tree, or the
10  * BSD license below:
11  *
12  *     Redistribution and use in source and binary forms, with or
13  *     without modification, are permitted provided that the following
14  *     conditions are met:
15  *
16  *      - Redistributions of source code must retain the above
17  *        copyright notice, this list of conditions and the following
18  *        disclaimer.
19  *
20  *      - Redistributions in binary form must reproduce the above
21  *        copyright notice, this list of conditions and the following
22  *        disclaimer in the documentation and/or other materials
23  *        provided with the distribution.
24  *
25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
26  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
27  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
28  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
29  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
30  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
31  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
32  * SOFTWARE.
33  */
34 
35 #include <linux/mm.h>
36 #include <linux/dma-mapping.h>
37 #include <linux/sched/signal.h>
38 #include <linux/sched/mm.h>
39 #include <linux/hugetlb.h>
40 #include <linux/iommu.h>
41 #include <linux/workqueue.h>
42 #include <linux/list.h>
43 #include <rdma/ib_verbs.h>
44 
45 #include "usnic_log.h"
46 #include "usnic_uiom.h"
47 #include "usnic_uiom_interval_tree.h"
48 
49 #define USNIC_UIOM_PAGE_CHUNK						\
50 	((PAGE_SIZE - offsetof(struct usnic_uiom_chunk, page_list))	/\
51 	((void *) &((struct usnic_uiom_chunk *) 0)->page_list[1] -	\
52 	(void *) &((struct usnic_uiom_chunk *) 0)->page_list[0]))
53 
54 static int usnic_uiom_dma_fault(struct iommu_domain *domain,
55 				struct device *dev,
56 				unsigned long iova, int flags,
57 				void *token)
58 {
59 	usnic_err("Device %s iommu fault domain 0x%pK va 0x%lx flags 0x%x\n",
60 		dev_name(dev),
61 		domain, iova, flags);
62 	return -ENOSYS;
63 }
64 
65 static void usnic_uiom_put_pages(struct list_head *chunk_list, int dirty)
66 {
67 	struct usnic_uiom_chunk *chunk, *tmp;
68 	struct page *page;
69 	struct scatterlist *sg;
70 	int i;
71 	dma_addr_t pa;
72 
73 	list_for_each_entry_safe(chunk, tmp, chunk_list, list) {
74 		for_each_sg(chunk->page_list, sg, chunk->nents, i) {
75 			page = sg_page(sg);
76 			pa = sg_phys(sg);
77 			unpin_user_pages_dirty_lock(&page, 1, dirty);
78 			usnic_dbg("pa: %pa\n", &pa);
79 		}
80 		kfree(chunk);
81 	}
82 }
83 
84 static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable,
85 				int dmasync, struct usnic_uiom_reg *uiomr)
86 {
87 	struct list_head *chunk_list = &uiomr->chunk_list;
88 	unsigned int gup_flags = FOLL_LONGTERM;
89 	struct page **page_list;
90 	struct scatterlist *sg;
91 	struct usnic_uiom_chunk *chunk;
92 	unsigned long locked;
93 	unsigned long lock_limit;
94 	unsigned long cur_base;
95 	unsigned long npages;
96 	int ret;
97 	int off;
98 	int i;
99 	dma_addr_t pa;
100 	struct mm_struct *mm;
101 
102 	/*
103 	 * If the combination of the addr and size requested for this memory
104 	 * region causes an integer overflow, return error.
105 	 */
106 	if (((addr + size) < addr) || PAGE_ALIGN(addr + size) < (addr + size))
107 		return -EINVAL;
108 
109 	if (!size)
110 		return -EINVAL;
111 
112 	if (!can_do_mlock())
113 		return -EPERM;
114 
115 	INIT_LIST_HEAD(chunk_list);
116 
117 	page_list = (struct page **) __get_free_page(GFP_KERNEL);
118 	if (!page_list)
119 		return -ENOMEM;
120 
121 	npages = PAGE_ALIGN(size + (addr & ~PAGE_MASK)) >> PAGE_SHIFT;
122 
123 	uiomr->owning_mm = mm = current->mm;
124 	mmap_read_lock(mm);
125 
126 	locked = atomic64_add_return(npages, &current->mm->pinned_vm);
127 	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
128 
129 	if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
130 		ret = -ENOMEM;
131 		goto out;
132 	}
133 
134 	if (writable)
135 		gup_flags |= FOLL_WRITE;
136 	cur_base = addr & PAGE_MASK;
137 	ret = 0;
138 
139 	while (npages) {
140 		ret = pin_user_pages(cur_base,
141 				     min_t(unsigned long, npages,
142 				     PAGE_SIZE / sizeof(struct page *)),
143 				     gup_flags, page_list, NULL);
144 
145 		if (ret < 0)
146 			goto out;
147 
148 		npages -= ret;
149 		off = 0;
150 
151 		while (ret) {
152 			chunk = kmalloc(struct_size(chunk, page_list,
153 					min_t(int, ret, USNIC_UIOM_PAGE_CHUNK)),
154 					GFP_KERNEL);
155 			if (!chunk) {
156 				ret = -ENOMEM;
157 				goto out;
158 			}
159 
160 			chunk->nents = min_t(int, ret, USNIC_UIOM_PAGE_CHUNK);
161 			sg_init_table(chunk->page_list, chunk->nents);
162 			for_each_sg(chunk->page_list, sg, chunk->nents, i) {
163 				sg_set_page(sg, page_list[i + off],
164 						PAGE_SIZE, 0);
165 				pa = sg_phys(sg);
166 				usnic_dbg("va: 0x%lx pa: %pa\n",
167 						cur_base + i*PAGE_SIZE, &pa);
168 			}
169 			cur_base += chunk->nents * PAGE_SIZE;
170 			ret -= chunk->nents;
171 			off += chunk->nents;
172 			list_add_tail(&chunk->list, chunk_list);
173 		}
174 
175 		ret = 0;
176 	}
177 
178 out:
179 	if (ret < 0) {
180 		usnic_uiom_put_pages(chunk_list, 0);
181 		atomic64_sub(npages, &current->mm->pinned_vm);
182 	} else
183 		mmgrab(uiomr->owning_mm);
184 
185 	mmap_read_unlock(mm);
186 	free_page((unsigned long) page_list);
187 	return ret;
188 }
189 
190 static void usnic_uiom_unmap_sorted_intervals(struct list_head *intervals,
191 						struct usnic_uiom_pd *pd)
192 {
193 	struct usnic_uiom_interval_node *interval, *tmp;
194 	long unsigned va, size;
195 
196 	list_for_each_entry_safe(interval, tmp, intervals, link) {
197 		va = interval->start << PAGE_SHIFT;
198 		size = ((interval->last - interval->start) + 1) << PAGE_SHIFT;
199 		while (size > 0) {
200 			/* Workaround for RH 970401 */
201 			usnic_dbg("va 0x%lx size 0x%lx", va, PAGE_SIZE);
202 			iommu_unmap(pd->domain, va, PAGE_SIZE);
203 			va += PAGE_SIZE;
204 			size -= PAGE_SIZE;
205 		}
206 	}
207 }
208 
209 static void __usnic_uiom_reg_release(struct usnic_uiom_pd *pd,
210 					struct usnic_uiom_reg *uiomr,
211 					int dirty)
212 {
213 	int npages;
214 	unsigned long vpn_start, vpn_last;
215 	struct usnic_uiom_interval_node *interval, *tmp;
216 	int writable = 0;
217 	LIST_HEAD(rm_intervals);
218 
219 	npages = PAGE_ALIGN(uiomr->length + uiomr->offset) >> PAGE_SHIFT;
220 	vpn_start = (uiomr->va & PAGE_MASK) >> PAGE_SHIFT;
221 	vpn_last = vpn_start + npages - 1;
222 
223 	spin_lock(&pd->lock);
224 	usnic_uiom_remove_interval(&pd->root, vpn_start,
225 					vpn_last, &rm_intervals);
226 	usnic_uiom_unmap_sorted_intervals(&rm_intervals, pd);
227 
228 	list_for_each_entry_safe(interval, tmp, &rm_intervals, link) {
229 		if (interval->flags & IOMMU_WRITE)
230 			writable = 1;
231 		list_del(&interval->link);
232 		kfree(interval);
233 	}
234 
235 	usnic_uiom_put_pages(&uiomr->chunk_list, dirty & writable);
236 	spin_unlock(&pd->lock);
237 }
238 
239 static int usnic_uiom_map_sorted_intervals(struct list_head *intervals,
240 						struct usnic_uiom_reg *uiomr)
241 {
242 	int i, err;
243 	size_t size;
244 	struct usnic_uiom_chunk *chunk;
245 	struct usnic_uiom_interval_node *interval_node;
246 	dma_addr_t pa;
247 	dma_addr_t pa_start = 0;
248 	dma_addr_t pa_end = 0;
249 	long int va_start = -EINVAL;
250 	struct usnic_uiom_pd *pd = uiomr->pd;
251 	long int va = uiomr->va & PAGE_MASK;
252 	int flags = IOMMU_READ | IOMMU_CACHE;
253 
254 	flags |= (uiomr->writable) ? IOMMU_WRITE : 0;
255 	chunk = list_first_entry(&uiomr->chunk_list, struct usnic_uiom_chunk,
256 									list);
257 	list_for_each_entry(interval_node, intervals, link) {
258 iter_chunk:
259 		for (i = 0; i < chunk->nents; i++, va += PAGE_SIZE) {
260 			pa = sg_phys(&chunk->page_list[i]);
261 			if ((va >> PAGE_SHIFT) < interval_node->start)
262 				continue;
263 
264 			if ((va >> PAGE_SHIFT) == interval_node->start) {
265 				/* First page of the interval */
266 				va_start = va;
267 				pa_start = pa;
268 				pa_end = pa;
269 			}
270 
271 			WARN_ON(va_start == -EINVAL);
272 
273 			if ((pa_end + PAGE_SIZE != pa) &&
274 					(pa != pa_start)) {
275 				/* PAs are not contiguous */
276 				size = pa_end - pa_start + PAGE_SIZE;
277 				usnic_dbg("va 0x%lx pa %pa size 0x%zx flags 0x%x",
278 					va_start, &pa_start, size, flags);
279 				err = iommu_map(pd->domain, va_start, pa_start,
280 						size, flags, GFP_ATOMIC);
281 				if (err) {
282 					usnic_err("Failed to map va 0x%lx pa %pa size 0x%zx with err %d\n",
283 						va_start, &pa_start, size, err);
284 					goto err_out;
285 				}
286 				va_start = va;
287 				pa_start = pa;
288 				pa_end = pa;
289 			}
290 
291 			if ((va >> PAGE_SHIFT) == interval_node->last) {
292 				/* Last page of the interval */
293 				size = pa - pa_start + PAGE_SIZE;
294 				usnic_dbg("va 0x%lx pa %pa size 0x%zx flags 0x%x\n",
295 					va_start, &pa_start, size, flags);
296 				err = iommu_map(pd->domain, va_start, pa_start,
297 						size, flags, GFP_ATOMIC);
298 				if (err) {
299 					usnic_err("Failed to map va 0x%lx pa %pa size 0x%zx with err %d\n",
300 						va_start, &pa_start, size, err);
301 					goto err_out;
302 				}
303 				break;
304 			}
305 
306 			if (pa != pa_start)
307 				pa_end += PAGE_SIZE;
308 		}
309 
310 		if (i == chunk->nents) {
311 			/*
312 			 * Hit last entry of the chunk,
313 			 * hence advance to next chunk
314 			 */
315 			chunk = list_first_entry(&chunk->list,
316 							struct usnic_uiom_chunk,
317 							list);
318 			goto iter_chunk;
319 		}
320 	}
321 
322 	return 0;
323 
324 err_out:
325 	usnic_uiom_unmap_sorted_intervals(intervals, pd);
326 	return err;
327 }
328 
329 struct usnic_uiom_reg *usnic_uiom_reg_get(struct usnic_uiom_pd *pd,
330 						unsigned long addr, size_t size,
331 						int writable, int dmasync)
332 {
333 	struct usnic_uiom_reg *uiomr;
334 	unsigned long va_base, vpn_start, vpn_last;
335 	unsigned long npages;
336 	int offset, err;
337 	LIST_HEAD(sorted_diff_intervals);
338 
339 	/*
340 	 * Intel IOMMU map throws an error if a translation entry is
341 	 * changed from read to write.  This module may not unmap
342 	 * and then remap the entry after fixing the permission
343 	 * b/c this open up a small windows where hw DMA may page fault
344 	 * Hence, make all entries to be writable.
345 	 */
346 	writable = 1;
347 
348 	va_base = addr & PAGE_MASK;
349 	offset = addr & ~PAGE_MASK;
350 	npages = PAGE_ALIGN(size + offset) >> PAGE_SHIFT;
351 	vpn_start = (addr & PAGE_MASK) >> PAGE_SHIFT;
352 	vpn_last = vpn_start + npages - 1;
353 
354 	uiomr = kmalloc(sizeof(*uiomr), GFP_KERNEL);
355 	if (!uiomr)
356 		return ERR_PTR(-ENOMEM);
357 
358 	uiomr->va = va_base;
359 	uiomr->offset = offset;
360 	uiomr->length = size;
361 	uiomr->writable = writable;
362 	uiomr->pd = pd;
363 
364 	err = usnic_uiom_get_pages(addr, size, writable, dmasync,
365 				   uiomr);
366 	if (err) {
367 		usnic_err("Failed get_pages vpn [0x%lx,0x%lx] err %d\n",
368 				vpn_start, vpn_last, err);
369 		goto out_free_uiomr;
370 	}
371 
372 	spin_lock(&pd->lock);
373 	err = usnic_uiom_get_intervals_diff(vpn_start, vpn_last,
374 						(writable) ? IOMMU_WRITE : 0,
375 						IOMMU_WRITE,
376 						&pd->root,
377 						&sorted_diff_intervals);
378 	if (err) {
379 		usnic_err("Failed disjoint interval vpn [0x%lx,0x%lx] err %d\n",
380 						vpn_start, vpn_last, err);
381 		goto out_put_pages;
382 	}
383 
384 	err = usnic_uiom_map_sorted_intervals(&sorted_diff_intervals, uiomr);
385 	if (err) {
386 		usnic_err("Failed map interval vpn [0x%lx,0x%lx] err %d\n",
387 						vpn_start, vpn_last, err);
388 		goto out_put_intervals;
389 
390 	}
391 
392 	err = usnic_uiom_insert_interval(&pd->root, vpn_start, vpn_last,
393 					(writable) ? IOMMU_WRITE : 0);
394 	if (err) {
395 		usnic_err("Failed insert interval vpn [0x%lx,0x%lx] err %d\n",
396 						vpn_start, vpn_last, err);
397 		goto out_unmap_intervals;
398 	}
399 
400 	usnic_uiom_put_interval_set(&sorted_diff_intervals);
401 	spin_unlock(&pd->lock);
402 
403 	return uiomr;
404 
405 out_unmap_intervals:
406 	usnic_uiom_unmap_sorted_intervals(&sorted_diff_intervals, pd);
407 out_put_intervals:
408 	usnic_uiom_put_interval_set(&sorted_diff_intervals);
409 out_put_pages:
410 	usnic_uiom_put_pages(&uiomr->chunk_list, 0);
411 	spin_unlock(&pd->lock);
412 	mmdrop(uiomr->owning_mm);
413 out_free_uiomr:
414 	kfree(uiomr);
415 	return ERR_PTR(err);
416 }
417 
418 static void __usnic_uiom_release_tail(struct usnic_uiom_reg *uiomr)
419 {
420 	mmdrop(uiomr->owning_mm);
421 	kfree(uiomr);
422 }
423 
424 static inline size_t usnic_uiom_num_pages(struct usnic_uiom_reg *uiomr)
425 {
426 	return PAGE_ALIGN(uiomr->length + uiomr->offset) >> PAGE_SHIFT;
427 }
428 
429 void usnic_uiom_reg_release(struct usnic_uiom_reg *uiomr)
430 {
431 	__usnic_uiom_reg_release(uiomr->pd, uiomr, 1);
432 
433 	atomic64_sub(usnic_uiom_num_pages(uiomr), &uiomr->owning_mm->pinned_vm);
434 	__usnic_uiom_release_tail(uiomr);
435 }
436 
437 struct usnic_uiom_pd *usnic_uiom_alloc_pd(struct device *dev)
438 {
439 	struct usnic_uiom_pd *pd;
440 	void *domain;
441 
442 	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
443 	if (!pd)
444 		return ERR_PTR(-ENOMEM);
445 
446 	pd->domain = domain = iommu_domain_alloc(dev->bus);
447 	if (!domain) {
448 		usnic_err("Failed to allocate IOMMU domain");
449 		kfree(pd);
450 		return ERR_PTR(-ENOMEM);
451 	}
452 
453 	iommu_set_fault_handler(pd->domain, usnic_uiom_dma_fault, NULL);
454 
455 	spin_lock_init(&pd->lock);
456 	INIT_LIST_HEAD(&pd->devs);
457 
458 	return pd;
459 }
460 
461 void usnic_uiom_dealloc_pd(struct usnic_uiom_pd *pd)
462 {
463 	iommu_domain_free(pd->domain);
464 	kfree(pd);
465 }
466 
467 int usnic_uiom_attach_dev_to_pd(struct usnic_uiom_pd *pd, struct device *dev)
468 {
469 	struct usnic_uiom_dev *uiom_dev;
470 	int err;
471 
472 	uiom_dev = kzalloc(sizeof(*uiom_dev), GFP_ATOMIC);
473 	if (!uiom_dev)
474 		return -ENOMEM;
475 	uiom_dev->dev = dev;
476 
477 	err = iommu_attach_device(pd->domain, dev);
478 	if (err)
479 		goto out_free_dev;
480 
481 	if (!device_iommu_capable(dev, IOMMU_CAP_CACHE_COHERENCY)) {
482 		usnic_err("IOMMU of %s does not support cache coherency\n",
483 				dev_name(dev));
484 		err = -EINVAL;
485 		goto out_detach_device;
486 	}
487 
488 	spin_lock(&pd->lock);
489 	list_add_tail(&uiom_dev->link, &pd->devs);
490 	pd->dev_cnt++;
491 	spin_unlock(&pd->lock);
492 
493 	return 0;
494 
495 out_detach_device:
496 	iommu_detach_device(pd->domain, dev);
497 out_free_dev:
498 	kfree(uiom_dev);
499 	return err;
500 }
501 
502 void usnic_uiom_detach_dev_from_pd(struct usnic_uiom_pd *pd, struct device *dev)
503 {
504 	struct usnic_uiom_dev *uiom_dev;
505 	int found = 0;
506 
507 	spin_lock(&pd->lock);
508 	list_for_each_entry(uiom_dev, &pd->devs, link) {
509 		if (uiom_dev->dev == dev) {
510 			found = 1;
511 			break;
512 		}
513 	}
514 
515 	if (!found) {
516 		usnic_err("Unable to free dev %s - not found\n",
517 				dev_name(dev));
518 		spin_unlock(&pd->lock);
519 		return;
520 	}
521 
522 	list_del(&uiom_dev->link);
523 	pd->dev_cnt--;
524 	spin_unlock(&pd->lock);
525 
526 	return iommu_detach_device(pd->domain, dev);
527 }
528 
529 struct device **usnic_uiom_get_dev_list(struct usnic_uiom_pd *pd)
530 {
531 	struct usnic_uiom_dev *uiom_dev;
532 	struct device **devs;
533 	int i = 0;
534 
535 	spin_lock(&pd->lock);
536 	devs = kcalloc(pd->dev_cnt + 1, sizeof(*devs), GFP_ATOMIC);
537 	if (!devs) {
538 		devs = ERR_PTR(-ENOMEM);
539 		goto out;
540 	}
541 
542 	list_for_each_entry(uiom_dev, &pd->devs, link) {
543 		devs[i++] = uiom_dev->dev;
544 	}
545 out:
546 	spin_unlock(&pd->lock);
547 	return devs;
548 }
549 
550 void usnic_uiom_free_dev_list(struct device **devs)
551 {
552 	kfree(devs);
553 }
554