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