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/cdev.h>
8 #include <linux/slab.h>
9 #include <linux/dax.h>
10 #include <linux/fs.h>
11 #include <linux/mm.h>
12 #include <linux/mman.h>
13 #include "dax-private.h"
14 #include "bus.h"
15
check_vma(struct dev_dax * dev_dax,struct vm_area_struct * vma,const char * func)16 static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
17 const char *func)
18 {
19 struct device *dev = &dev_dax->dev;
20 unsigned long mask;
21
22 if (!dax_alive(dev_dax->dax_dev))
23 return -ENXIO;
24
25 /* prevent private mappings from being established */
26 if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
27 dev_info_ratelimited(dev,
28 "%s: %s: fail, attempted private mapping\n",
29 current->comm, func);
30 return -EINVAL;
31 }
32
33 mask = dev_dax->align - 1;
34 if (vma->vm_start & mask || vma->vm_end & mask) {
35 dev_info_ratelimited(dev,
36 "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
37 current->comm, func, vma->vm_start, vma->vm_end,
38 mask);
39 return -EINVAL;
40 }
41
42 if (!vma_is_dax(vma)) {
43 dev_info_ratelimited(dev,
44 "%s: %s: fail, vma is not DAX capable\n",
45 current->comm, func);
46 return -EINVAL;
47 }
48
49 return 0;
50 }
51
52 /* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
dax_pgoff_to_phys(struct dev_dax * dev_dax,pgoff_t pgoff,unsigned long size)53 __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
54 unsigned long size)
55 {
56 int i;
57
58 for (i = 0; i < dev_dax->nr_range; i++) {
59 struct dev_dax_range *dax_range = &dev_dax->ranges[i];
60 struct range *range = &dax_range->range;
61 unsigned long long pgoff_end;
62 phys_addr_t phys;
63
64 pgoff_end = dax_range->pgoff + PHYS_PFN(range_len(range)) - 1;
65 if (pgoff < dax_range->pgoff || pgoff > pgoff_end)
66 continue;
67 phys = PFN_PHYS(pgoff - dax_range->pgoff) + range->start;
68 if (phys + size - 1 <= range->end)
69 return phys;
70 break;
71 }
72 return -1;
73 }
74
dax_set_mapping(struct vm_fault * vmf,unsigned long pfn,unsigned long fault_size)75 static void dax_set_mapping(struct vm_fault *vmf, unsigned long pfn,
76 unsigned long fault_size)
77 {
78 unsigned long i, nr_pages = fault_size / PAGE_SIZE;
79 struct file *filp = vmf->vma->vm_file;
80 struct dev_dax *dev_dax = filp->private_data;
81 pgoff_t pgoff;
82
83 /* mapping is only set on the head */
84 if (dev_dax->pgmap->vmemmap_shift)
85 nr_pages = 1;
86
87 pgoff = linear_page_index(vmf->vma,
88 ALIGN_DOWN(vmf->address, fault_size));
89
90 for (i = 0; i < nr_pages; i++) {
91 struct folio *folio = pfn_folio(pfn + i);
92
93 if (folio->mapping)
94 continue;
95
96 folio->mapping = filp->f_mapping;
97 folio->index = pgoff + i;
98 }
99 }
100
__dev_dax_pte_fault(struct dev_dax * dev_dax,struct vm_fault * vmf)101 static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
102 struct vm_fault *vmf)
103 {
104 struct device *dev = &dev_dax->dev;
105 phys_addr_t phys;
106 unsigned long pfn;
107 unsigned int fault_size = PAGE_SIZE;
108
109 if (check_vma(dev_dax, vmf->vma, __func__))
110 return VM_FAULT_SIGBUS;
111
112 if (dev_dax->align > PAGE_SIZE) {
113 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
114 dev_dax->align, fault_size);
115 return VM_FAULT_SIGBUS;
116 }
117
118 if (fault_size != dev_dax->align)
119 return VM_FAULT_SIGBUS;
120
121 phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
122 if (phys == -1) {
123 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
124 return VM_FAULT_SIGBUS;
125 }
126
127 pfn = PHYS_PFN(phys);
128
129 dax_set_mapping(vmf, pfn, fault_size);
130
131 return vmf_insert_page_mkwrite(vmf, pfn_to_page(pfn),
132 vmf->flags & FAULT_FLAG_WRITE);
133 }
134
__dev_dax_pmd_fault(struct dev_dax * dev_dax,struct vm_fault * vmf)135 static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
136 struct vm_fault *vmf)
137 {
138 unsigned long pmd_addr = vmf->address & PMD_MASK;
139 struct device *dev = &dev_dax->dev;
140 phys_addr_t phys;
141 pgoff_t pgoff;
142 unsigned long pfn;
143 unsigned int fault_size = PMD_SIZE;
144
145 if (check_vma(dev_dax, vmf->vma, __func__))
146 return VM_FAULT_SIGBUS;
147
148 if (dev_dax->align > PMD_SIZE) {
149 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
150 dev_dax->align, fault_size);
151 return VM_FAULT_SIGBUS;
152 }
153
154 if (fault_size < dev_dax->align)
155 return VM_FAULT_SIGBUS;
156 else if (fault_size > dev_dax->align)
157 return VM_FAULT_FALLBACK;
158
159 /* if we are outside of the VMA */
160 if (pmd_addr < vmf->vma->vm_start ||
161 (pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
162 return VM_FAULT_SIGBUS;
163
164 pgoff = linear_page_index(vmf->vma, pmd_addr);
165 phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
166 if (phys == -1) {
167 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
168 return VM_FAULT_SIGBUS;
169 }
170
171 pfn = PHYS_PFN(phys);
172
173 dax_set_mapping(vmf, pfn, fault_size);
174
175 return vmf_insert_folio_pmd(vmf, page_folio(pfn_to_page(pfn)),
176 vmf->flags & FAULT_FLAG_WRITE);
177 }
178
179 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
__dev_dax_pud_fault(struct dev_dax * dev_dax,struct vm_fault * vmf)180 static 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 unsigned long 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_PFN(phys);
218
219 dax_set_mapping(vmf, pfn, fault_size);
220
221 return vmf_insert_folio_pud(vmf, page_folio(pfn_to_page(pfn)),
222 vmf->flags & FAULT_FLAG_WRITE);
223 }
224 #else
__dev_dax_pud_fault(struct dev_dax * dev_dax,struct vm_fault * vmf)225 static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
226 struct vm_fault *vmf)
227 {
228 return VM_FAULT_FALLBACK;
229 }
230 #endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
231
dev_dax_huge_fault(struct vm_fault * vmf,unsigned int order)232 static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, unsigned int order)
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: op=%s addr=%#lx order=%d\n", current->comm,
240 (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
241 vmf->address & ~((1UL << (order + PAGE_SHIFT)) - 1), order);
242
243 id = dax_read_lock();
244 if (order == 0)
245 rc = __dev_dax_pte_fault(dev_dax, vmf);
246 else if (order == PMD_ORDER)
247 rc = __dev_dax_pmd_fault(dev_dax, vmf);
248 else if (order == PUD_ORDER)
249 rc = __dev_dax_pud_fault(dev_dax, vmf);
250 else
251 rc = VM_FAULT_SIGBUS;
252
253 dax_read_unlock(id);
254
255 return rc;
256 }
257
dev_dax_fault(struct vm_fault * vmf)258 static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
259 {
260 return dev_dax_huge_fault(vmf, 0);
261 }
262
dev_dax_may_split(struct vm_area_struct * vma,unsigned long addr)263 static int dev_dax_may_split(struct vm_area_struct *vma, unsigned long addr)
264 {
265 struct file *filp = vma->vm_file;
266 struct dev_dax *dev_dax = filp->private_data;
267
268 if (!IS_ALIGNED(addr, dev_dax->align))
269 return -EINVAL;
270 return 0;
271 }
272
dev_dax_pagesize(struct vm_area_struct * vma)273 static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
274 {
275 struct file *filp = vma->vm_file;
276 struct dev_dax *dev_dax = filp->private_data;
277
278 return dev_dax->align;
279 }
280
281 static const struct vm_operations_struct dax_vm_ops = {
282 .fault = dev_dax_fault,
283 .huge_fault = dev_dax_huge_fault,
284 .may_split = dev_dax_may_split,
285 .pagesize = dev_dax_pagesize,
286 };
287
dax_mmap(struct file * filp,struct vm_area_struct * vma)288 static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
289 {
290 struct dev_dax *dev_dax = filp->private_data;
291 int rc, id;
292
293 dev_dbg(&dev_dax->dev, "trace\n");
294
295 /*
296 * We lock to check dax_dev liveness and will re-check at
297 * fault time.
298 */
299 id = dax_read_lock();
300 rc = check_vma(dev_dax, vma, __func__);
301 dax_read_unlock(id);
302 if (rc)
303 return rc;
304
305 vma->vm_ops = &dax_vm_ops;
306 vm_flags_set(vma, VM_HUGEPAGE);
307 return 0;
308 }
309
310 /* return an unmapped area aligned to the dax region specified alignment */
dax_get_unmapped_area(struct file * filp,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)311 static unsigned long dax_get_unmapped_area(struct file *filp,
312 unsigned long addr, unsigned long len, unsigned long pgoff,
313 unsigned long flags)
314 {
315 unsigned long off, off_end, off_align, len_align, addr_align, align;
316 struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
317
318 if (!dev_dax || addr)
319 goto out;
320
321 align = dev_dax->align;
322 off = pgoff << PAGE_SHIFT;
323 off_end = off + len;
324 off_align = round_up(off, align);
325
326 if ((off_end <= off_align) || ((off_end - off_align) < align))
327 goto out;
328
329 len_align = len + align;
330 if ((off + len_align) < off)
331 goto out;
332
333 addr_align = mm_get_unmapped_area(current->mm, filp, addr, len_align,
334 pgoff, flags);
335 if (!IS_ERR_VALUE(addr_align)) {
336 addr_align += (off - addr_align) & (align - 1);
337 return addr_align;
338 }
339 out:
340 return mm_get_unmapped_area(current->mm, filp, addr, len, pgoff, flags);
341 }
342
343 static const struct address_space_operations dev_dax_aops = {
344 .dirty_folio = noop_dirty_folio,
345 };
346
dax_open(struct inode * inode,struct file * filp)347 static int dax_open(struct inode *inode, struct file *filp)
348 {
349 struct dax_device *dax_dev = inode_dax(inode);
350 struct inode *__dax_inode = dax_inode(dax_dev);
351 struct dev_dax *dev_dax = dax_get_private(dax_dev);
352
353 dev_dbg(&dev_dax->dev, "trace\n");
354 inode->i_mapping = __dax_inode->i_mapping;
355 inode->i_mapping->host = __dax_inode;
356 inode->i_mapping->a_ops = &dev_dax_aops;
357 filp->f_mapping = inode->i_mapping;
358 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
359 filp->f_sb_err = file_sample_sb_err(filp);
360 filp->private_data = dev_dax;
361 inode->i_flags = S_DAX;
362
363 return 0;
364 }
365
dax_release(struct inode * inode,struct file * filp)366 static int dax_release(struct inode *inode, struct file *filp)
367 {
368 struct dev_dax *dev_dax = filp->private_data;
369
370 dev_dbg(&dev_dax->dev, "trace\n");
371 return 0;
372 }
373
374 static const struct file_operations dax_fops = {
375 .llseek = noop_llseek,
376 .owner = THIS_MODULE,
377 .open = dax_open,
378 .release = dax_release,
379 .get_unmapped_area = dax_get_unmapped_area,
380 .mmap = dax_mmap,
381 .fop_flags = FOP_MMAP_SYNC,
382 };
383
dev_dax_cdev_del(void * cdev)384 static void dev_dax_cdev_del(void *cdev)
385 {
386 cdev_del(cdev);
387 }
388
dev_dax_kill(void * dev_dax)389 static void dev_dax_kill(void *dev_dax)
390 {
391 kill_dev_dax(dev_dax);
392 }
393
dev_dax_probe(struct dev_dax * dev_dax)394 static int dev_dax_probe(struct dev_dax *dev_dax)
395 {
396 struct dax_device *dax_dev = dev_dax->dax_dev;
397 struct device *dev = &dev_dax->dev;
398 struct dev_pagemap *pgmap;
399 struct inode *inode;
400 struct cdev *cdev;
401 void *addr;
402 int rc, i;
403
404 if (static_dev_dax(dev_dax)) {
405 if (dev_dax->nr_range > 1) {
406 dev_warn(dev,
407 "static pgmap / multi-range device conflict\n");
408 return -EINVAL;
409 }
410
411 pgmap = dev_dax->pgmap;
412 } else {
413 if (dev_dax->pgmap) {
414 dev_warn(dev,
415 "dynamic-dax with pre-populated page map\n");
416 return -EINVAL;
417 }
418
419 pgmap = devm_kzalloc(dev,
420 struct_size(pgmap, ranges, dev_dax->nr_range - 1),
421 GFP_KERNEL);
422 if (!pgmap)
423 return -ENOMEM;
424
425 pgmap->nr_range = dev_dax->nr_range;
426 dev_dax->pgmap = pgmap;
427
428 for (i = 0; i < dev_dax->nr_range; i++) {
429 struct range *range = &dev_dax->ranges[i].range;
430 pgmap->ranges[i] = *range;
431 }
432 }
433
434 for (i = 0; i < dev_dax->nr_range; i++) {
435 struct range *range = &dev_dax->ranges[i].range;
436
437 if (!devm_request_mem_region(dev, range->start,
438 range_len(range), dev_name(dev))) {
439 dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve range\n",
440 i, range->start, range->end);
441 return -EBUSY;
442 }
443 }
444
445 pgmap->type = MEMORY_DEVICE_GENERIC;
446 if (dev_dax->align > PAGE_SIZE)
447 pgmap->vmemmap_shift =
448 order_base_2(dev_dax->align >> PAGE_SHIFT);
449 addr = devm_memremap_pages(dev, pgmap);
450 if (IS_ERR(addr))
451 return PTR_ERR(addr);
452
453 inode = dax_inode(dax_dev);
454 cdev = inode->i_cdev;
455 cdev_init(cdev, &dax_fops);
456 cdev->owner = dev->driver->owner;
457 cdev_set_parent(cdev, &dev->kobj);
458 rc = cdev_add(cdev, dev->devt, 1);
459 if (rc)
460 return rc;
461
462 rc = devm_add_action_or_reset(dev, dev_dax_cdev_del, cdev);
463 if (rc)
464 return rc;
465
466 run_dax(dax_dev);
467 return devm_add_action_or_reset(dev, dev_dax_kill, dev_dax);
468 }
469
470 static struct dax_device_driver device_dax_driver = {
471 .probe = dev_dax_probe,
472 .type = DAXDRV_DEVICE_TYPE,
473 };
474
dax_init(void)475 static int __init dax_init(void)
476 {
477 return dax_driver_register(&device_dax_driver);
478 }
479
dax_exit(void)480 static void __exit dax_exit(void)
481 {
482 dax_driver_unregister(&device_dax_driver);
483 }
484
485 MODULE_AUTHOR("Intel Corporation");
486 MODULE_DESCRIPTION("Device DAX: direct access device driver");
487 MODULE_LICENSE("GPL v2");
488 module_init(dax_init);
489 module_exit(dax_exit);
490 MODULE_ALIAS_DAX_DEVICE(0);
491