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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 device *dev = &dev_dax->dev;
21 unsigned long mask;
22
23 if (!dax_alive(dev_dax->dax_dev))
24 return -ENXIO;
25
26 /* prevent private mappings from being established */
27 if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
28 dev_info_ratelimited(dev,
29 "%s: %s: fail, attempted private mapping\n",
30 current->comm, func);
31 return -EINVAL;
32 }
33
34 mask = dev_dax->align - 1;
35 if (vma->vm_start & mask || vma->vm_end & mask) {
36 dev_info_ratelimited(dev,
37 "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
38 current->comm, func, vma->vm_start, vma->vm_end,
39 mask);
40 return -EINVAL;
41 }
42
43 if (!vma_is_dax(vma)) {
44 dev_info_ratelimited(dev,
45 "%s: %s: fail, vma is not DAX capable\n",
46 current->comm, func);
47 return -EINVAL;
48 }
49
50 return 0;
51}
52
53/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
54__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
55 unsigned long size)
56{
57 int i;
58
59 for (i = 0; i < dev_dax->nr_range; i++) {
60 struct dev_dax_range *dax_range = &dev_dax->ranges[i];
61 struct range *range = &dax_range->range;
62 unsigned long long pgoff_end;
63 phys_addr_t phys;
64
65 pgoff_end = dax_range->pgoff + PHYS_PFN(range_len(range)) - 1;
66 if (pgoff < dax_range->pgoff || pgoff > pgoff_end)
67 continue;
68 phys = PFN_PHYS(pgoff - dax_range->pgoff) + range->start;
69 if (phys + size - 1 <= range->end)
70 return phys;
71 break;
72 }
73 return -1;
74}
75
76static void dax_set_mapping(struct vm_fault *vmf, pfn_t pfn,
77 unsigned long fault_size)
78{
79 unsigned long i, nr_pages = fault_size / PAGE_SIZE;
80 struct file *filp = vmf->vma->vm_file;
81 struct dev_dax *dev_dax = filp->private_data;
82 pgoff_t pgoff;
83
84 /* mapping is only set on the head */
85 if (dev_dax->pgmap->vmemmap_shift)
86 nr_pages = 1;
87
88 pgoff = linear_page_index(vmf->vma,
89 ALIGN(vmf->address, fault_size));
90
91 for (i = 0; i < nr_pages; i++) {
92 struct page *page = pfn_to_page(pfn_t_to_pfn(pfn) + i);
93
94 page = compound_head(page);
95 if (page->mapping)
96 continue;
97
98 page->mapping = filp->f_mapping;
99 page->index = pgoff + i;
100 }
101}
102
103static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
104 struct vm_fault *vmf)
105{
106 struct device *dev = &dev_dax->dev;
107 phys_addr_t phys;
108 pfn_t pfn;
109 unsigned int fault_size = PAGE_SIZE;
110
111 if (check_vma(dev_dax, vmf->vma, __func__))
112 return VM_FAULT_SIGBUS;
113
114 if (dev_dax->align > PAGE_SIZE) {
115 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
116 dev_dax->align, fault_size);
117 return VM_FAULT_SIGBUS;
118 }
119
120 if (fault_size != dev_dax->align)
121 return VM_FAULT_SIGBUS;
122
123 phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
124 if (phys == -1) {
125 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
126 return VM_FAULT_SIGBUS;
127 }
128
129 pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
130
131 dax_set_mapping(vmf, pfn, fault_size);
132
133 return vmf_insert_mixed(vmf->vma, vmf->address, pfn);
134}
135
136static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
137 struct vm_fault *vmf)
138{
139 unsigned long pmd_addr = vmf->address & PMD_MASK;
140 struct device *dev = &dev_dax->dev;
141 phys_addr_t phys;
142 pgoff_t pgoff;
143 pfn_t pfn;
144 unsigned int fault_size = PMD_SIZE;
145
146 if (check_vma(dev_dax, vmf->vma, __func__))
147 return VM_FAULT_SIGBUS;
148
149 if (dev_dax->align > PMD_SIZE) {
150 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
151 dev_dax->align, fault_size);
152 return VM_FAULT_SIGBUS;
153 }
154
155 if (fault_size < dev_dax->align)
156 return VM_FAULT_SIGBUS;
157 else if (fault_size > dev_dax->align)
158 return VM_FAULT_FALLBACK;
159
160 /* if we are outside of the VMA */
161 if (pmd_addr < vmf->vma->vm_start ||
162 (pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
163 return VM_FAULT_SIGBUS;
164
165 pgoff = linear_page_index(vmf->vma, pmd_addr);
166 phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
167 if (phys == -1) {
168 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
169 return VM_FAULT_SIGBUS;
170 }
171
172 pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
173
174 dax_set_mapping(vmf, pfn, fault_size);
175
176 return vmf_insert_pfn_pmd(vmf, pfn, vmf->flags & FAULT_FLAG_WRITE);
177}
178
179#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
180static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
181 struct vm_fault *vmf)
182{
183 unsigned long pud_addr = vmf->address & PUD_MASK;
184 struct device *dev = &dev_dax->dev;
185 phys_addr_t phys;
186 pgoff_t pgoff;
187 pfn_t pfn;
188 unsigned int fault_size = PUD_SIZE;
189
190
191 if (check_vma(dev_dax, vmf->vma, __func__))
192 return VM_FAULT_SIGBUS;
193
194 if (dev_dax->align > PUD_SIZE) {
195 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
196 dev_dax->align, fault_size);
197 return VM_FAULT_SIGBUS;
198 }
199
200 if (fault_size < dev_dax->align)
201 return VM_FAULT_SIGBUS;
202 else if (fault_size > dev_dax->align)
203 return VM_FAULT_FALLBACK;
204
205 /* if we are outside of the VMA */
206 if (pud_addr < vmf->vma->vm_start ||
207 (pud_addr + PUD_SIZE) > vmf->vma->vm_end)
208 return VM_FAULT_SIGBUS;
209
210 pgoff = linear_page_index(vmf->vma, pud_addr);
211 phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
212 if (phys == -1) {
213 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
214 return VM_FAULT_SIGBUS;
215 }
216
217 pfn = phys_to_pfn_t(phys, PFN_DEV|PFN_MAP);
218
219 dax_set_mapping(vmf, pfn, fault_size);
220
221 return vmf_insert_pfn_pud(vmf, pfn, vmf->flags & FAULT_FLAG_WRITE);
222}
223#else
224static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
225 struct vm_fault *vmf)
226{
227 return VM_FAULT_FALLBACK;
228}
229#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
230
231static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
232 enum page_entry_size pe_size)
233{
234 struct file *filp = vmf->vma->vm_file;
235 vm_fault_t rc = VM_FAULT_SIGBUS;
236 int id;
237 struct dev_dax *dev_dax = filp->private_data;
238
239 dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
240 (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
241 vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
242
243 id = dax_read_lock();
244 switch (pe_size) {
245 case PE_SIZE_PTE:
246 rc = __dev_dax_pte_fault(dev_dax, vmf);
247 break;
248 case PE_SIZE_PMD:
249 rc = __dev_dax_pmd_fault(dev_dax, vmf);
250 break;
251 case PE_SIZE_PUD:
252 rc = __dev_dax_pud_fault(dev_dax, vmf);
253 break;
254 default:
255 rc = VM_FAULT_SIGBUS;
256 }
257
258 dax_read_unlock(id);
259
260 return rc;
261}
262
263static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
264{
265 return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
266}
267
268static int dev_dax_may_split(struct vm_area_struct *vma, unsigned long addr)
269{
270 struct file *filp = vma->vm_file;
271 struct dev_dax *dev_dax = filp->private_data;
272
273 if (!IS_ALIGNED(addr, dev_dax->align))
274 return -EINVAL;
275 return 0;
276}
277
278static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
279{
280 struct file *filp = vma->vm_file;
281 struct dev_dax *dev_dax = filp->private_data;
282
283 return dev_dax->align;
284}
285
286static const struct vm_operations_struct dax_vm_ops = {
287 .fault = dev_dax_fault,
288 .huge_fault = dev_dax_huge_fault,
289 .may_split = dev_dax_may_split,
290 .pagesize = dev_dax_pagesize,
291};
292
293static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
294{
295 struct dev_dax *dev_dax = filp->private_data;
296 int rc, id;
297
298 dev_dbg(&dev_dax->dev, "trace\n");
299
300 /*
301 * We lock to check dax_dev liveness and will re-check at
302 * fault time.
303 */
304 id = dax_read_lock();
305 rc = check_vma(dev_dax, vma, __func__);
306 dax_read_unlock(id);
307 if (rc)
308 return rc;
309
310 vma->vm_ops = &dax_vm_ops;
311 vma->vm_flags |= VM_HUGEPAGE;
312 return 0;
313}
314
315/* return an unmapped area aligned to the dax region specified alignment */
316static unsigned long dax_get_unmapped_area(struct file *filp,
317 unsigned long addr, unsigned long len, unsigned long pgoff,
318 unsigned long flags)
319{
320 unsigned long off, off_end, off_align, len_align, addr_align, align;
321 struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
322
323 if (!dev_dax || addr)
324 goto out;
325
326 align = dev_dax->align;
327 off = pgoff << PAGE_SHIFT;
328 off_end = off + len;
329 off_align = round_up(off, align);
330
331 if ((off_end <= off_align) || ((off_end - off_align) < align))
332 goto out;
333
334 len_align = len + align;
335 if ((off + len_align) < off)
336 goto out;
337
338 addr_align = current->mm->get_unmapped_area(filp, addr, len_align,
339 pgoff, flags);
340 if (!IS_ERR_VALUE(addr_align)) {
341 addr_align += (off - addr_align) & (align - 1);
342 return addr_align;
343 }
344 out:
345 return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
346}
347
348static const struct address_space_operations dev_dax_aops = {
349 .dirty_folio = noop_dirty_folio,
350};
351
352static int dax_open(struct inode *inode, struct file *filp)
353{
354 struct dax_device *dax_dev = inode_dax(inode);
355 struct inode *__dax_inode = dax_inode(dax_dev);
356 struct dev_dax *dev_dax = dax_get_private(dax_dev);
357
358 dev_dbg(&dev_dax->dev, "trace\n");
359 inode->i_mapping = __dax_inode->i_mapping;
360 inode->i_mapping->host = __dax_inode;
361 inode->i_mapping->a_ops = &dev_dax_aops;
362 filp->f_mapping = inode->i_mapping;
363 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
364 filp->f_sb_err = file_sample_sb_err(filp);
365 filp->private_data = dev_dax;
366 inode->i_flags = S_DAX;
367
368 return 0;
369}
370
371static int dax_release(struct inode *inode, struct file *filp)
372{
373 struct dev_dax *dev_dax = filp->private_data;
374
375 dev_dbg(&dev_dax->dev, "trace\n");
376 return 0;
377}
378
379static const struct file_operations dax_fops = {
380 .llseek = noop_llseek,
381 .owner = THIS_MODULE,
382 .open = dax_open,
383 .release = dax_release,
384 .get_unmapped_area = dax_get_unmapped_area,
385 .mmap = dax_mmap,
386 .mmap_supported_flags = MAP_SYNC,
387};
388
389static void dev_dax_cdev_del(void *cdev)
390{
391 cdev_del(cdev);
392}
393
394static void dev_dax_kill(void *dev_dax)
395{
396 kill_dev_dax(dev_dax);
397}
398
399int dev_dax_probe(struct dev_dax *dev_dax)
400{
401 struct dax_device *dax_dev = dev_dax->dax_dev;
402 struct device *dev = &dev_dax->dev;
403 struct dev_pagemap *pgmap;
404 struct inode *inode;
405 struct cdev *cdev;
406 void *addr;
407 int rc, i;
408
409 if (static_dev_dax(dev_dax)) {
410 if (dev_dax->nr_range > 1) {
411 dev_warn(dev,
412 "static pgmap / multi-range device conflict\n");
413 return -EINVAL;
414 }
415
416 pgmap = dev_dax->pgmap;
417 } else {
418 if (dev_dax->pgmap) {
419 dev_warn(dev,
420 "dynamic-dax with pre-populated page map\n");
421 return -EINVAL;
422 }
423
424 pgmap = devm_kzalloc(dev,
425 struct_size(pgmap, ranges, dev_dax->nr_range - 1),
426 GFP_KERNEL);
427 if (!pgmap)
428 return -ENOMEM;
429
430 pgmap->nr_range = dev_dax->nr_range;
431 dev_dax->pgmap = pgmap;
432
433 for (i = 0; i < dev_dax->nr_range; i++) {
434 struct range *range = &dev_dax->ranges[i].range;
435 pgmap->ranges[i] = *range;
436 }
437 }
438
439 for (i = 0; i < dev_dax->nr_range; i++) {
440 struct range *range = &dev_dax->ranges[i].range;
441
442 if (!devm_request_mem_region(dev, range->start,
443 range_len(range), dev_name(dev))) {
444 dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve range\n",
445 i, range->start, range->end);
446 return -EBUSY;
447 }
448 }
449
450 pgmap->type = MEMORY_DEVICE_GENERIC;
451 if (dev_dax->align > PAGE_SIZE)
452 pgmap->vmemmap_shift =
453 order_base_2(dev_dax->align >> PAGE_SHIFT);
454 addr = devm_memremap_pages(dev, pgmap);
455 if (IS_ERR(addr))
456 return PTR_ERR(addr);
457
458 inode = dax_inode(dax_dev);
459 cdev = inode->i_cdev;
460 cdev_init(cdev, &dax_fops);
461 cdev->owner = dev->driver->owner;
462 cdev_set_parent(cdev, &dev->kobj);
463 rc = cdev_add(cdev, dev->devt, 1);
464 if (rc)
465 return rc;
466
467 rc = devm_add_action_or_reset(dev, dev_dax_cdev_del, cdev);
468 if (rc)
469 return rc;
470
471 run_dax(dax_dev);
472 return devm_add_action_or_reset(dev, dev_dax_kill, dev_dax);
473}
474EXPORT_SYMBOL_GPL(dev_dax_probe);
475
476static struct dax_device_driver device_dax_driver = {
477 .probe = dev_dax_probe,
478 /* all probe actions are unwound by devm, so .remove isn't necessary */
479 .match_always = 1,
480};
481
482static int __init dax_init(void)
483{
484 return dax_driver_register(&device_dax_driver);
485}
486
487static void __exit dax_exit(void)
488{
489 dax_driver_unregister(&device_dax_driver);
490}
491
492MODULE_AUTHOR("Intel Corporation");
493MODULE_LICENSE("GPL v2");
494module_init(dax_init);
495module_exit(dax_exit);
496MODULE_ALIAS_DAX_DEVICE(0);