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1/*
2 * Copyright(c) 2016 - 2017 Intel Corporation. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of version 2 of the GNU General Public License as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 */
13#include <linux/pagemap.h>
14#include <linux/module.h>
15#include <linux/device.h>
16#include <linux/pfn_t.h>
17#include <linux/cdev.h>
18#include <linux/slab.h>
19#include <linux/dax.h>
20#include <linux/fs.h>
21#include <linux/mm.h>
22#include <linux/mman.h>
23#include "dax-private.h"
24#include "dax.h"
25
26static struct class *dax_class;
27
28/*
29 * Rely on the fact that drvdata is set before the attributes are
30 * registered, and that the attributes are unregistered before drvdata
31 * is cleared to assume that drvdata is always valid.
32 */
33static ssize_t id_show(struct device *dev,
34 struct device_attribute *attr, char *buf)
35{
36 struct dax_region *dax_region = dev_get_drvdata(dev);
37
38 return sprintf(buf, "%d\n", dax_region->id);
39}
40static DEVICE_ATTR_RO(id);
41
42static ssize_t region_size_show(struct device *dev,
43 struct device_attribute *attr, char *buf)
44{
45 struct dax_region *dax_region = dev_get_drvdata(dev);
46
47 return sprintf(buf, "%llu\n", (unsigned long long)
48 resource_size(&dax_region->res));
49}
50static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
51 region_size_show, NULL);
52
53static ssize_t align_show(struct device *dev,
54 struct device_attribute *attr, char *buf)
55{
56 struct dax_region *dax_region = dev_get_drvdata(dev);
57
58 return sprintf(buf, "%u\n", dax_region->align);
59}
60static DEVICE_ATTR_RO(align);
61
62static struct attribute *dax_region_attributes[] = {
63 &dev_attr_region_size.attr,
64 &dev_attr_align.attr,
65 &dev_attr_id.attr,
66 NULL,
67};
68
69static const struct attribute_group dax_region_attribute_group = {
70 .name = "dax_region",
71 .attrs = dax_region_attributes,
72};
73
74static const struct attribute_group *dax_region_attribute_groups[] = {
75 &dax_region_attribute_group,
76 NULL,
77};
78
79static void dax_region_free(struct kref *kref)
80{
81 struct dax_region *dax_region;
82
83 dax_region = container_of(kref, struct dax_region, kref);
84 kfree(dax_region);
85}
86
87void dax_region_put(struct dax_region *dax_region)
88{
89 kref_put(&dax_region->kref, dax_region_free);
90}
91EXPORT_SYMBOL_GPL(dax_region_put);
92
93static void dax_region_unregister(void *region)
94{
95 struct dax_region *dax_region = region;
96
97 sysfs_remove_groups(&dax_region->dev->kobj,
98 dax_region_attribute_groups);
99 dax_region_put(dax_region);
100}
101
102struct dax_region *alloc_dax_region(struct device *parent, int region_id,
103 struct resource *res, unsigned int align, void *addr,
104 unsigned long pfn_flags)
105{
106 struct dax_region *dax_region;
107
108 /*
109 * The DAX core assumes that it can store its private data in
110 * parent->driver_data. This WARN is a reminder / safeguard for
111 * developers of device-dax drivers.
112 */
113 if (dev_get_drvdata(parent)) {
114 dev_WARN(parent, "dax core failed to setup private data\n");
115 return NULL;
116 }
117
118 if (!IS_ALIGNED(res->start, align)
119 || !IS_ALIGNED(resource_size(res), align))
120 return NULL;
121
122 dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
123 if (!dax_region)
124 return NULL;
125
126 dev_set_drvdata(parent, dax_region);
127 memcpy(&dax_region->res, res, sizeof(*res));
128 dax_region->pfn_flags = pfn_flags;
129 kref_init(&dax_region->kref);
130 dax_region->id = region_id;
131 ida_init(&dax_region->ida);
132 dax_region->align = align;
133 dax_region->dev = parent;
134 dax_region->base = addr;
135 if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
136 kfree(dax_region);
137 return NULL;
138 }
139
140 kref_get(&dax_region->kref);
141 if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
142 return NULL;
143 return dax_region;
144}
145EXPORT_SYMBOL_GPL(alloc_dax_region);
146
147static struct dev_dax *to_dev_dax(struct device *dev)
148{
149 return container_of(dev, struct dev_dax, dev);
150}
151
152static ssize_t size_show(struct device *dev,
153 struct device_attribute *attr, char *buf)
154{
155 struct dev_dax *dev_dax = to_dev_dax(dev);
156 unsigned long long size = 0;
157 int i;
158
159 for (i = 0; i < dev_dax->num_resources; i++)
160 size += resource_size(&dev_dax->res[i]);
161
162 return sprintf(buf, "%llu\n", size);
163}
164static DEVICE_ATTR_RO(size);
165
166static struct attribute *dev_dax_attributes[] = {
167 &dev_attr_size.attr,
168 NULL,
169};
170
171static const struct attribute_group dev_dax_attribute_group = {
172 .attrs = dev_dax_attributes,
173};
174
175static const struct attribute_group *dax_attribute_groups[] = {
176 &dev_dax_attribute_group,
177 NULL,
178};
179
180static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
181 const char *func)
182{
183 struct dax_region *dax_region = dev_dax->region;
184 struct device *dev = &dev_dax->dev;
185 unsigned long mask;
186
187 if (!dax_alive(dev_dax->dax_dev))
188 return -ENXIO;
189
190 /* prevent private mappings from being established */
191 if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
192 dev_info(dev, "%s: %s: fail, attempted private mapping\n",
193 current->comm, func);
194 return -EINVAL;
195 }
196
197 mask = dax_region->align - 1;
198 if (vma->vm_start & mask || vma->vm_end & mask) {
199 dev_info(dev, "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
200 current->comm, func, vma->vm_start, vma->vm_end,
201 mask);
202 return -EINVAL;
203 }
204
205 if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV
206 && (vma->vm_flags & VM_DONTCOPY) == 0) {
207 dev_info(dev, "%s: %s: fail, dax range requires MADV_DONTFORK\n",
208 current->comm, func);
209 return -EINVAL;
210 }
211
212 if (!vma_is_dax(vma)) {
213 dev_info(dev, "%s: %s: fail, vma is not DAX capable\n",
214 current->comm, func);
215 return -EINVAL;
216 }
217
218 return 0;
219}
220
221/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
222__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
223 unsigned long size)
224{
225 struct resource *res;
226 /* gcc-4.6.3-nolibc for i386 complains that this is uninitialized */
227 phys_addr_t uninitialized_var(phys);
228 int i;
229
230 for (i = 0; i < dev_dax->num_resources; i++) {
231 res = &dev_dax->res[i];
232 phys = pgoff * PAGE_SIZE + res->start;
233 if (phys >= res->start && phys <= res->end)
234 break;
235 pgoff -= PHYS_PFN(resource_size(res));
236 }
237
238 if (i < dev_dax->num_resources) {
239 res = &dev_dax->res[i];
240 if (phys + size - 1 <= res->end)
241 return phys;
242 }
243
244 return -1;
245}
246
247static int __dev_dax_pte_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
248{
249 struct device *dev = &dev_dax->dev;
250 struct dax_region *dax_region;
251 int rc = VM_FAULT_SIGBUS;
252 phys_addr_t phys;
253 pfn_t pfn;
254 unsigned int fault_size = PAGE_SIZE;
255
256 if (check_vma(dev_dax, vmf->vma, __func__))
257 return VM_FAULT_SIGBUS;
258
259 dax_region = dev_dax->region;
260 if (dax_region->align > PAGE_SIZE) {
261 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
262 dax_region->align, fault_size);
263 return VM_FAULT_SIGBUS;
264 }
265
266 if (fault_size != dax_region->align)
267 return VM_FAULT_SIGBUS;
268
269 phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
270 if (phys == -1) {
271 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
272 return VM_FAULT_SIGBUS;
273 }
274
275 pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
276
277 rc = vm_insert_mixed(vmf->vma, vmf->address, pfn);
278
279 if (rc == -ENOMEM)
280 return VM_FAULT_OOM;
281 if (rc < 0 && rc != -EBUSY)
282 return VM_FAULT_SIGBUS;
283
284 return VM_FAULT_NOPAGE;
285}
286
287static int __dev_dax_pmd_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
288{
289 unsigned long pmd_addr = vmf->address & PMD_MASK;
290 struct device *dev = &dev_dax->dev;
291 struct dax_region *dax_region;
292 phys_addr_t phys;
293 pgoff_t pgoff;
294 pfn_t pfn;
295 unsigned int fault_size = PMD_SIZE;
296
297 if (check_vma(dev_dax, vmf->vma, __func__))
298 return VM_FAULT_SIGBUS;
299
300 dax_region = dev_dax->region;
301 if (dax_region->align > PMD_SIZE) {
302 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
303 dax_region->align, fault_size);
304 return VM_FAULT_SIGBUS;
305 }
306
307 /* dax pmd mappings require pfn_t_devmap() */
308 if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
309 dev_dbg(dev, "region lacks devmap flags\n");
310 return VM_FAULT_SIGBUS;
311 }
312
313 if (fault_size < dax_region->align)
314 return VM_FAULT_SIGBUS;
315 else if (fault_size > dax_region->align)
316 return VM_FAULT_FALLBACK;
317
318 /* if we are outside of the VMA */
319 if (pmd_addr < vmf->vma->vm_start ||
320 (pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
321 return VM_FAULT_SIGBUS;
322
323 pgoff = linear_page_index(vmf->vma, pmd_addr);
324 phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
325 if (phys == -1) {
326 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
327 return VM_FAULT_SIGBUS;
328 }
329
330 pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
331
332 return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, pfn,
333 vmf->flags & FAULT_FLAG_WRITE);
334}
335
336#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
337static int __dev_dax_pud_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
338{
339 unsigned long pud_addr = vmf->address & PUD_MASK;
340 struct device *dev = &dev_dax->dev;
341 struct dax_region *dax_region;
342 phys_addr_t phys;
343 pgoff_t pgoff;
344 pfn_t pfn;
345 unsigned int fault_size = PUD_SIZE;
346
347
348 if (check_vma(dev_dax, vmf->vma, __func__))
349 return VM_FAULT_SIGBUS;
350
351 dax_region = dev_dax->region;
352 if (dax_region->align > PUD_SIZE) {
353 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
354 dax_region->align, fault_size);
355 return VM_FAULT_SIGBUS;
356 }
357
358 /* dax pud mappings require pfn_t_devmap() */
359 if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
360 dev_dbg(dev, "region lacks devmap flags\n");
361 return VM_FAULT_SIGBUS;
362 }
363
364 if (fault_size < dax_region->align)
365 return VM_FAULT_SIGBUS;
366 else if (fault_size > dax_region->align)
367 return VM_FAULT_FALLBACK;
368
369 /* if we are outside of the VMA */
370 if (pud_addr < vmf->vma->vm_start ||
371 (pud_addr + PUD_SIZE) > vmf->vma->vm_end)
372 return VM_FAULT_SIGBUS;
373
374 pgoff = linear_page_index(vmf->vma, pud_addr);
375 phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
376 if (phys == -1) {
377 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
378 return VM_FAULT_SIGBUS;
379 }
380
381 pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
382
383 return vmf_insert_pfn_pud(vmf->vma, vmf->address, vmf->pud, pfn,
384 vmf->flags & FAULT_FLAG_WRITE);
385}
386#else
387static int __dev_dax_pud_fault(struct dev_dax *dev_dax, struct vm_fault *vmf)
388{
389 return VM_FAULT_FALLBACK;
390}
391#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
392
393static int dev_dax_huge_fault(struct vm_fault *vmf,
394 enum page_entry_size pe_size)
395{
396 int rc, id;
397 struct file *filp = vmf->vma->vm_file;
398 struct dev_dax *dev_dax = filp->private_data;
399
400 dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
401 (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
402 vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
403
404 id = dax_read_lock();
405 switch (pe_size) {
406 case PE_SIZE_PTE:
407 rc = __dev_dax_pte_fault(dev_dax, vmf);
408 break;
409 case PE_SIZE_PMD:
410 rc = __dev_dax_pmd_fault(dev_dax, vmf);
411 break;
412 case PE_SIZE_PUD:
413 rc = __dev_dax_pud_fault(dev_dax, vmf);
414 break;
415 default:
416 rc = VM_FAULT_SIGBUS;
417 }
418 dax_read_unlock(id);
419
420 return rc;
421}
422
423static int dev_dax_fault(struct vm_fault *vmf)
424{
425 return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
426}
427
428static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr)
429{
430 struct file *filp = vma->vm_file;
431 struct dev_dax *dev_dax = filp->private_data;
432 struct dax_region *dax_region = dev_dax->region;
433
434 if (!IS_ALIGNED(addr, dax_region->align))
435 return -EINVAL;
436 return 0;
437}
438
439static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
440{
441 struct file *filp = vma->vm_file;
442 struct dev_dax *dev_dax = filp->private_data;
443 struct dax_region *dax_region = dev_dax->region;
444
445 return dax_region->align;
446}
447
448static const struct vm_operations_struct dax_vm_ops = {
449 .fault = dev_dax_fault,
450 .huge_fault = dev_dax_huge_fault,
451 .split = dev_dax_split,
452 .pagesize = dev_dax_pagesize,
453};
454
455static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
456{
457 struct dev_dax *dev_dax = filp->private_data;
458 int rc, id;
459
460 dev_dbg(&dev_dax->dev, "trace\n");
461
462 /*
463 * We lock to check dax_dev liveness and will re-check at
464 * fault time.
465 */
466 id = dax_read_lock();
467 rc = check_vma(dev_dax, vma, __func__);
468 dax_read_unlock(id);
469 if (rc)
470 return rc;
471
472 vma->vm_ops = &dax_vm_ops;
473 vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
474 return 0;
475}
476
477/* return an unmapped area aligned to the dax region specified alignment */
478static unsigned long dax_get_unmapped_area(struct file *filp,
479 unsigned long addr, unsigned long len, unsigned long pgoff,
480 unsigned long flags)
481{
482 unsigned long off, off_end, off_align, len_align, addr_align, align;
483 struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
484 struct dax_region *dax_region;
485
486 if (!dev_dax || addr)
487 goto out;
488
489 dax_region = dev_dax->region;
490 align = dax_region->align;
491 off = pgoff << PAGE_SHIFT;
492 off_end = off + len;
493 off_align = round_up(off, align);
494
495 if ((off_end <= off_align) || ((off_end - off_align) < align))
496 goto out;
497
498 len_align = len + align;
499 if ((off + len_align) < off)
500 goto out;
501
502 addr_align = current->mm->get_unmapped_area(filp, addr, len_align,
503 pgoff, flags);
504 if (!IS_ERR_VALUE(addr_align)) {
505 addr_align += (off - addr_align) & (align - 1);
506 return addr_align;
507 }
508 out:
509 return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
510}
511
512static int dax_open(struct inode *inode, struct file *filp)
513{
514 struct dax_device *dax_dev = inode_dax(inode);
515 struct inode *__dax_inode = dax_inode(dax_dev);
516 struct dev_dax *dev_dax = dax_get_private(dax_dev);
517
518 dev_dbg(&dev_dax->dev, "trace\n");
519 inode->i_mapping = __dax_inode->i_mapping;
520 inode->i_mapping->host = __dax_inode;
521 filp->f_mapping = inode->i_mapping;
522 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
523 filp->private_data = dev_dax;
524 inode->i_flags = S_DAX;
525
526 return 0;
527}
528
529static int dax_release(struct inode *inode, struct file *filp)
530{
531 struct dev_dax *dev_dax = filp->private_data;
532
533 dev_dbg(&dev_dax->dev, "trace\n");
534 return 0;
535}
536
537static const struct file_operations dax_fops = {
538 .llseek = noop_llseek,
539 .owner = THIS_MODULE,
540 .open = dax_open,
541 .release = dax_release,
542 .get_unmapped_area = dax_get_unmapped_area,
543 .mmap = dax_mmap,
544 .mmap_supported_flags = MAP_SYNC,
545};
546
547static void dev_dax_release(struct device *dev)
548{
549 struct dev_dax *dev_dax = to_dev_dax(dev);
550 struct dax_region *dax_region = dev_dax->region;
551 struct dax_device *dax_dev = dev_dax->dax_dev;
552
553 if (dev_dax->id >= 0)
554 ida_simple_remove(&dax_region->ida, dev_dax->id);
555 dax_region_put(dax_region);
556 put_dax(dax_dev);
557 kfree(dev_dax);
558}
559
560static void kill_dev_dax(struct dev_dax *dev_dax)
561{
562 struct dax_device *dax_dev = dev_dax->dax_dev;
563 struct inode *inode = dax_inode(dax_dev);
564
565 kill_dax(dax_dev);
566 unmap_mapping_range(inode->i_mapping, 0, 0, 1);
567}
568
569static void unregister_dev_dax(void *dev)
570{
571 struct dev_dax *dev_dax = to_dev_dax(dev);
572 struct dax_device *dax_dev = dev_dax->dax_dev;
573 struct inode *inode = dax_inode(dax_dev);
574 struct cdev *cdev = inode->i_cdev;
575
576 dev_dbg(dev, "trace\n");
577
578 kill_dev_dax(dev_dax);
579 cdev_device_del(cdev, dev);
580 put_device(dev);
581}
582
583struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
584 int id, struct resource *res, int count)
585{
586 struct device *parent = dax_region->dev;
587 struct dax_device *dax_dev;
588 struct dev_dax *dev_dax;
589 struct inode *inode;
590 struct device *dev;
591 struct cdev *cdev;
592 int rc, i;
593
594 if (!count)
595 return ERR_PTR(-EINVAL);
596
597 dev_dax = kzalloc(sizeof(*dev_dax) + sizeof(*res) * count, GFP_KERNEL);
598 if (!dev_dax)
599 return ERR_PTR(-ENOMEM);
600
601 for (i = 0; i < count; i++) {
602 if (!IS_ALIGNED(res[i].start, dax_region->align)
603 || !IS_ALIGNED(resource_size(&res[i]),
604 dax_region->align)) {
605 rc = -EINVAL;
606 break;
607 }
608 dev_dax->res[i].start = res[i].start;
609 dev_dax->res[i].end = res[i].end;
610 }
611
612 if (i < count)
613 goto err_id;
614
615 if (id < 0) {
616 id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL);
617 dev_dax->id = id;
618 if (id < 0) {
619 rc = id;
620 goto err_id;
621 }
622 } else {
623 /* region provider owns @id lifetime */
624 dev_dax->id = -1;
625 }
626
627 /*
628 * No 'host' or dax_operations since there is no access to this
629 * device outside of mmap of the resulting character device.
630 */
631 dax_dev = alloc_dax(dev_dax, NULL, NULL);
632 if (!dax_dev) {
633 rc = -ENOMEM;
634 goto err_dax;
635 }
636
637 /* from here on we're committed to teardown via dax_dev_release() */
638 dev = &dev_dax->dev;
639 device_initialize(dev);
640
641 inode = dax_inode(dax_dev);
642 cdev = inode->i_cdev;
643 cdev_init(cdev, &dax_fops);
644 cdev->owner = parent->driver->owner;
645
646 dev_dax->num_resources = count;
647 dev_dax->dax_dev = dax_dev;
648 dev_dax->region = dax_region;
649 kref_get(&dax_region->kref);
650
651 dev->devt = inode->i_rdev;
652 dev->class = dax_class;
653 dev->parent = parent;
654 dev->groups = dax_attribute_groups;
655 dev->release = dev_dax_release;
656 dev_set_name(dev, "dax%d.%d", dax_region->id, id);
657
658 rc = cdev_device_add(cdev, dev);
659 if (rc) {
660 kill_dev_dax(dev_dax);
661 put_device(dev);
662 return ERR_PTR(rc);
663 }
664
665 rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev);
666 if (rc)
667 return ERR_PTR(rc);
668
669 return dev_dax;
670
671 err_dax:
672 if (dev_dax->id >= 0)
673 ida_simple_remove(&dax_region->ida, dev_dax->id);
674 err_id:
675 kfree(dev_dax);
676
677 return ERR_PTR(rc);
678}
679EXPORT_SYMBOL_GPL(devm_create_dev_dax);
680
681static int __init dax_init(void)
682{
683 dax_class = class_create(THIS_MODULE, "dax");
684 return PTR_ERR_OR_ZERO(dax_class);
685}
686
687static void __exit dax_exit(void)
688{
689 class_destroy(dax_class);
690}
691
692MODULE_AUTHOR("Intel Corporation");
693MODULE_LICENSE("GPL v2");
694subsys_initcall(dax_init);
695module_exit(dax_exit);
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright(c) 2016-2018 Intel Corporation. All rights reserved. */
3#include <linux/memremap.h>
4#include <linux/pagemap.h>
5#include <linux/module.h>
6#include <linux/device.h>
7#include <linux/pfn_t.h>
8#include <linux/cdev.h>
9#include <linux/slab.h>
10#include <linux/dax.h>
11#include <linux/fs.h>
12#include <linux/mm.h>
13#include <linux/mman.h>
14#include "dax-private.h"
15#include "bus.h"
16
17static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
18 const char *func)
19{
20 struct dax_region *dax_region = dev_dax->region;
21 struct device *dev = &dev_dax->dev;
22 unsigned long mask;
23
24 if (!dax_alive(dev_dax->dax_dev))
25 return -ENXIO;
26
27 /* prevent private mappings from being established */
28 if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
29 dev_info_ratelimited(dev,
30 "%s: %s: fail, attempted private mapping\n",
31 current->comm, func);
32 return -EINVAL;
33 }
34
35 mask = dax_region->align - 1;
36 if (vma->vm_start & mask || vma->vm_end & mask) {
37 dev_info_ratelimited(dev,
38 "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
39 current->comm, func, vma->vm_start, vma->vm_end,
40 mask);
41 return -EINVAL;
42 }
43
44 if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV
45 && (vma->vm_flags & VM_DONTCOPY) == 0) {
46 dev_info_ratelimited(dev,
47 "%s: %s: fail, dax range requires MADV_DONTFORK\n",
48 current->comm, func);
49 return -EINVAL;
50 }
51
52 if (!vma_is_dax(vma)) {
53 dev_info_ratelimited(dev,
54 "%s: %s: fail, vma is not DAX capable\n",
55 current->comm, func);
56 return -EINVAL;
57 }
58
59 return 0;
60}
61
62/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
63__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
64 unsigned long size)
65{
66 struct resource *res = &dev_dax->region->res;
67 phys_addr_t phys;
68
69 phys = pgoff * PAGE_SIZE + res->start;
70 if (phys >= res->start && phys <= res->end) {
71 if (phys + size - 1 <= res->end)
72 return phys;
73 }
74
75 return -1;
76}
77
78static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
79 struct vm_fault *vmf, pfn_t *pfn)
80{
81 struct device *dev = &dev_dax->dev;
82 struct dax_region *dax_region;
83 phys_addr_t phys;
84 unsigned int fault_size = PAGE_SIZE;
85
86 if (check_vma(dev_dax, vmf->vma, __func__))
87 return VM_FAULT_SIGBUS;
88
89 dax_region = dev_dax->region;
90 if (dax_region->align > PAGE_SIZE) {
91 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
92 dax_region->align, fault_size);
93 return VM_FAULT_SIGBUS;
94 }
95
96 if (fault_size != dax_region->align)
97 return VM_FAULT_SIGBUS;
98
99 phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
100 if (phys == -1) {
101 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
102 return VM_FAULT_SIGBUS;
103 }
104
105 *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
106
107 return vmf_insert_mixed(vmf->vma, vmf->address, *pfn);
108}
109
110static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
111 struct vm_fault *vmf, pfn_t *pfn)
112{
113 unsigned long pmd_addr = vmf->address & PMD_MASK;
114 struct device *dev = &dev_dax->dev;
115 struct dax_region *dax_region;
116 phys_addr_t phys;
117 pgoff_t pgoff;
118 unsigned int fault_size = PMD_SIZE;
119
120 if (check_vma(dev_dax, vmf->vma, __func__))
121 return VM_FAULT_SIGBUS;
122
123 dax_region = dev_dax->region;
124 if (dax_region->align > PMD_SIZE) {
125 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
126 dax_region->align, fault_size);
127 return VM_FAULT_SIGBUS;
128 }
129
130 /* dax pmd mappings require pfn_t_devmap() */
131 if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
132 dev_dbg(dev, "region lacks devmap flags\n");
133 return VM_FAULT_SIGBUS;
134 }
135
136 if (fault_size < dax_region->align)
137 return VM_FAULT_SIGBUS;
138 else if (fault_size > dax_region->align)
139 return VM_FAULT_FALLBACK;
140
141 /* if we are outside of the VMA */
142 if (pmd_addr < vmf->vma->vm_start ||
143 (pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
144 return VM_FAULT_SIGBUS;
145
146 pgoff = linear_page_index(vmf->vma, pmd_addr);
147 phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
148 if (phys == -1) {
149 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
150 return VM_FAULT_SIGBUS;
151 }
152
153 *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
154
155 return vmf_insert_pfn_pmd(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE);
156}
157
158#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
159static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
160 struct vm_fault *vmf, pfn_t *pfn)
161{
162 unsigned long pud_addr = vmf->address & PUD_MASK;
163 struct device *dev = &dev_dax->dev;
164 struct dax_region *dax_region;
165 phys_addr_t phys;
166 pgoff_t pgoff;
167 unsigned int fault_size = PUD_SIZE;
168
169
170 if (check_vma(dev_dax, vmf->vma, __func__))
171 return VM_FAULT_SIGBUS;
172
173 dax_region = dev_dax->region;
174 if (dax_region->align > PUD_SIZE) {
175 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
176 dax_region->align, fault_size);
177 return VM_FAULT_SIGBUS;
178 }
179
180 /* dax pud mappings require pfn_t_devmap() */
181 if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
182 dev_dbg(dev, "region lacks devmap flags\n");
183 return VM_FAULT_SIGBUS;
184 }
185
186 if (fault_size < dax_region->align)
187 return VM_FAULT_SIGBUS;
188 else if (fault_size > dax_region->align)
189 return VM_FAULT_FALLBACK;
190
191 /* if we are outside of the VMA */
192 if (pud_addr < vmf->vma->vm_start ||
193 (pud_addr + PUD_SIZE) > vmf->vma->vm_end)
194 return VM_FAULT_SIGBUS;
195
196 pgoff = linear_page_index(vmf->vma, pud_addr);
197 phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
198 if (phys == -1) {
199 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
200 return VM_FAULT_SIGBUS;
201 }
202
203 *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
204
205 return vmf_insert_pfn_pud(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE);
206}
207#else
208static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
209 struct vm_fault *vmf, pfn_t *pfn)
210{
211 return VM_FAULT_FALLBACK;
212}
213#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
214
215static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
216 enum page_entry_size pe_size)
217{
218 struct file *filp = vmf->vma->vm_file;
219 unsigned long fault_size;
220 vm_fault_t rc = VM_FAULT_SIGBUS;
221 int id;
222 pfn_t pfn;
223 struct dev_dax *dev_dax = filp->private_data;
224
225 dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
226 (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
227 vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
228
229 id = dax_read_lock();
230 switch (pe_size) {
231 case PE_SIZE_PTE:
232 fault_size = PAGE_SIZE;
233 rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn);
234 break;
235 case PE_SIZE_PMD:
236 fault_size = PMD_SIZE;
237 rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn);
238 break;
239 case PE_SIZE_PUD:
240 fault_size = PUD_SIZE;
241 rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn);
242 break;
243 default:
244 rc = VM_FAULT_SIGBUS;
245 }
246
247 if (rc == VM_FAULT_NOPAGE) {
248 unsigned long i;
249 pgoff_t pgoff;
250
251 /*
252 * In the device-dax case the only possibility for a
253 * VM_FAULT_NOPAGE result is when device-dax capacity is
254 * mapped. No need to consider the zero page, or racing
255 * conflicting mappings.
256 */
257 pgoff = linear_page_index(vmf->vma, vmf->address
258 & ~(fault_size - 1));
259 for (i = 0; i < fault_size / PAGE_SIZE; i++) {
260 struct page *page;
261
262 page = pfn_to_page(pfn_t_to_pfn(pfn) + i);
263 if (page->mapping)
264 continue;
265 page->mapping = filp->f_mapping;
266 page->index = pgoff + i;
267 }
268 }
269 dax_read_unlock(id);
270
271 return rc;
272}
273
274static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
275{
276 return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
277}
278
279static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr)
280{
281 struct file *filp = vma->vm_file;
282 struct dev_dax *dev_dax = filp->private_data;
283 struct dax_region *dax_region = dev_dax->region;
284
285 if (!IS_ALIGNED(addr, dax_region->align))
286 return -EINVAL;
287 return 0;
288}
289
290static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
291{
292 struct file *filp = vma->vm_file;
293 struct dev_dax *dev_dax = filp->private_data;
294 struct dax_region *dax_region = dev_dax->region;
295
296 return dax_region->align;
297}
298
299static const struct vm_operations_struct dax_vm_ops = {
300 .fault = dev_dax_fault,
301 .huge_fault = dev_dax_huge_fault,
302 .split = dev_dax_split,
303 .pagesize = dev_dax_pagesize,
304};
305
306static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
307{
308 struct dev_dax *dev_dax = filp->private_data;
309 int rc, id;
310
311 dev_dbg(&dev_dax->dev, "trace\n");
312
313 /*
314 * We lock to check dax_dev liveness and will re-check at
315 * fault time.
316 */
317 id = dax_read_lock();
318 rc = check_vma(dev_dax, vma, __func__);
319 dax_read_unlock(id);
320 if (rc)
321 return rc;
322
323 vma->vm_ops = &dax_vm_ops;
324 vma->vm_flags |= VM_HUGEPAGE;
325 return 0;
326}
327
328/* return an unmapped area aligned to the dax region specified alignment */
329static unsigned long dax_get_unmapped_area(struct file *filp,
330 unsigned long addr, unsigned long len, unsigned long pgoff,
331 unsigned long flags)
332{
333 unsigned long off, off_end, off_align, len_align, addr_align, align;
334 struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
335 struct dax_region *dax_region;
336
337 if (!dev_dax || addr)
338 goto out;
339
340 dax_region = dev_dax->region;
341 align = dax_region->align;
342 off = pgoff << PAGE_SHIFT;
343 off_end = off + len;
344 off_align = round_up(off, align);
345
346 if ((off_end <= off_align) || ((off_end - off_align) < align))
347 goto out;
348
349 len_align = len + align;
350 if ((off + len_align) < off)
351 goto out;
352
353 addr_align = current->mm->get_unmapped_area(filp, addr, len_align,
354 pgoff, flags);
355 if (!IS_ERR_VALUE(addr_align)) {
356 addr_align += (off - addr_align) & (align - 1);
357 return addr_align;
358 }
359 out:
360 return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
361}
362
363static const struct address_space_operations dev_dax_aops = {
364 .set_page_dirty = noop_set_page_dirty,
365 .invalidatepage = noop_invalidatepage,
366};
367
368static int dax_open(struct inode *inode, struct file *filp)
369{
370 struct dax_device *dax_dev = inode_dax(inode);
371 struct inode *__dax_inode = dax_inode(dax_dev);
372 struct dev_dax *dev_dax = dax_get_private(dax_dev);
373
374 dev_dbg(&dev_dax->dev, "trace\n");
375 inode->i_mapping = __dax_inode->i_mapping;
376 inode->i_mapping->host = __dax_inode;
377 inode->i_mapping->a_ops = &dev_dax_aops;
378 filp->f_mapping = inode->i_mapping;
379 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
380 filp->private_data = dev_dax;
381 inode->i_flags = S_DAX;
382
383 return 0;
384}
385
386static int dax_release(struct inode *inode, struct file *filp)
387{
388 struct dev_dax *dev_dax = filp->private_data;
389
390 dev_dbg(&dev_dax->dev, "trace\n");
391 return 0;
392}
393
394static const struct file_operations dax_fops = {
395 .llseek = noop_llseek,
396 .owner = THIS_MODULE,
397 .open = dax_open,
398 .release = dax_release,
399 .get_unmapped_area = dax_get_unmapped_area,
400 .mmap = dax_mmap,
401 .mmap_supported_flags = MAP_SYNC,
402};
403
404static void dev_dax_cdev_del(void *cdev)
405{
406 cdev_del(cdev);
407}
408
409static void dev_dax_kill(void *dev_dax)
410{
411 kill_dev_dax(dev_dax);
412}
413
414int dev_dax_probe(struct device *dev)
415{
416 struct dev_dax *dev_dax = to_dev_dax(dev);
417 struct dax_device *dax_dev = dev_dax->dax_dev;
418 struct resource *res = &dev_dax->region->res;
419 struct inode *inode;
420 struct cdev *cdev;
421 void *addr;
422 int rc;
423
424 /* 1:1 map region resource range to device-dax instance range */
425 if (!devm_request_mem_region(dev, res->start, resource_size(res),
426 dev_name(dev))) {
427 dev_warn(dev, "could not reserve region %pR\n", res);
428 return -EBUSY;
429 }
430
431 dev_dax->pgmap.type = MEMORY_DEVICE_DEVDAX;
432 addr = devm_memremap_pages(dev, &dev_dax->pgmap);
433 if (IS_ERR(addr))
434 return PTR_ERR(addr);
435
436 inode = dax_inode(dax_dev);
437 cdev = inode->i_cdev;
438 cdev_init(cdev, &dax_fops);
439 if (dev->class) {
440 /* for the CONFIG_DEV_DAX_PMEM_COMPAT case */
441 cdev->owner = dev->parent->driver->owner;
442 } else
443 cdev->owner = dev->driver->owner;
444 cdev_set_parent(cdev, &dev->kobj);
445 rc = cdev_add(cdev, dev->devt, 1);
446 if (rc)
447 return rc;
448
449 rc = devm_add_action_or_reset(dev, dev_dax_cdev_del, cdev);
450 if (rc)
451 return rc;
452
453 run_dax(dax_dev);
454 return devm_add_action_or_reset(dev, dev_dax_kill, dev_dax);
455}
456EXPORT_SYMBOL_GPL(dev_dax_probe);
457
458static int dev_dax_remove(struct device *dev)
459{
460 /* all probe actions are unwound by devm */
461 return 0;
462}
463
464static struct dax_device_driver device_dax_driver = {
465 .drv = {
466 .probe = dev_dax_probe,
467 .remove = dev_dax_remove,
468 },
469 .match_always = 1,
470};
471
472static int __init dax_init(void)
473{
474 return dax_driver_register(&device_dax_driver);
475}
476
477static void __exit dax_exit(void)
478{
479 dax_driver_unregister(&device_dax_driver);
480}
481
482MODULE_AUTHOR("Intel Corporation");
483MODULE_LICENSE("GPL v2");
484module_init(dax_init);
485module_exit(dax_exit);
486MODULE_ALIAS_DAX_DEVICE(0);