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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 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->f_sb_err = file_sample_sb_err(filp);
381 filp->private_data = dev_dax;
382 inode->i_flags = S_DAX;
383
384 return 0;
385}
386
387static int dax_release(struct inode *inode, struct file *filp)
388{
389 struct dev_dax *dev_dax = filp->private_data;
390
391 dev_dbg(&dev_dax->dev, "trace\n");
392 return 0;
393}
394
395static const struct file_operations dax_fops = {
396 .llseek = noop_llseek,
397 .owner = THIS_MODULE,
398 .open = dax_open,
399 .release = dax_release,
400 .get_unmapped_area = dax_get_unmapped_area,
401 .mmap = dax_mmap,
402 .mmap_supported_flags = MAP_SYNC,
403};
404
405static void dev_dax_cdev_del(void *cdev)
406{
407 cdev_del(cdev);
408}
409
410static void dev_dax_kill(void *dev_dax)
411{
412 kill_dev_dax(dev_dax);
413}
414
415int dev_dax_probe(struct device *dev)
416{
417 struct dev_dax *dev_dax = to_dev_dax(dev);
418 struct dax_device *dax_dev = dev_dax->dax_dev;
419 struct resource *res = &dev_dax->region->res;
420 struct inode *inode;
421 struct cdev *cdev;
422 void *addr;
423 int rc;
424
425 /* 1:1 map region resource range to device-dax instance range */
426 if (!devm_request_mem_region(dev, res->start, resource_size(res),
427 dev_name(dev))) {
428 dev_warn(dev, "could not reserve region %pR\n", res);
429 return -EBUSY;
430 }
431
432 dev_dax->pgmap.type = MEMORY_DEVICE_GENERIC;
433 addr = devm_memremap_pages(dev, &dev_dax->pgmap);
434 if (IS_ERR(addr))
435 return PTR_ERR(addr);
436
437 inode = dax_inode(dax_dev);
438 cdev = inode->i_cdev;
439 cdev_init(cdev, &dax_fops);
440 if (dev->class) {
441 /* for the CONFIG_DEV_DAX_PMEM_COMPAT case */
442 cdev->owner = dev->parent->driver->owner;
443 } else
444 cdev->owner = dev->driver->owner;
445 cdev_set_parent(cdev, &dev->kobj);
446 rc = cdev_add(cdev, dev->devt, 1);
447 if (rc)
448 return rc;
449
450 rc = devm_add_action_or_reset(dev, dev_dax_cdev_del, cdev);
451 if (rc)
452 return rc;
453
454 run_dax(dax_dev);
455 return devm_add_action_or_reset(dev, dev_dax_kill, dev_dax);
456}
457EXPORT_SYMBOL_GPL(dev_dax_probe);
458
459static int dev_dax_remove(struct device *dev)
460{
461 /* all probe actions are unwound by devm */
462 return 0;
463}
464
465static struct dax_device_driver device_dax_driver = {
466 .drv = {
467 .probe = dev_dax_probe,
468 .remove = dev_dax_remove,
469 },
470 .match_always = 1,
471};
472
473static int __init dax_init(void)
474{
475 return dax_driver_register(&device_dax_driver);
476}
477
478static void __exit dax_exit(void)
479{
480 dax_driver_unregister(&device_dax_driver);
481}
482
483MODULE_AUTHOR("Intel Corporation");
484MODULE_LICENSE("GPL v2");
485module_init(dax_init);
486module_exit(dax_exit);
487MODULE_ALIAS_DAX_DEVICE(0);
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, unsigned int order)
232{
233 struct file *filp = vmf->vma->vm_file;
234 vm_fault_t rc = VM_FAULT_SIGBUS;
235 int id;
236 struct dev_dax *dev_dax = filp->private_data;
237
238 dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) order:%d\n", current->comm,
239 (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
240 vmf->vma->vm_start, vmf->vma->vm_end, order);
241
242 id = dax_read_lock();
243 if (order == 0)
244 rc = __dev_dax_pte_fault(dev_dax, vmf);
245 else if (order == PMD_ORDER)
246 rc = __dev_dax_pmd_fault(dev_dax, vmf);
247 else if (order == PUD_ORDER)
248 rc = __dev_dax_pud_fault(dev_dax, vmf);
249 else
250 rc = VM_FAULT_SIGBUS;
251
252 dax_read_unlock(id);
253
254 return rc;
255}
256
257static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
258{
259 return dev_dax_huge_fault(vmf, 0);
260}
261
262static int dev_dax_may_split(struct vm_area_struct *vma, unsigned long addr)
263{
264 struct file *filp = vma->vm_file;
265 struct dev_dax *dev_dax = filp->private_data;
266
267 if (!IS_ALIGNED(addr, dev_dax->align))
268 return -EINVAL;
269 return 0;
270}
271
272static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
273{
274 struct file *filp = vma->vm_file;
275 struct dev_dax *dev_dax = filp->private_data;
276
277 return dev_dax->align;
278}
279
280static const struct vm_operations_struct dax_vm_ops = {
281 .fault = dev_dax_fault,
282 .huge_fault = dev_dax_huge_fault,
283 .may_split = dev_dax_may_split,
284 .pagesize = dev_dax_pagesize,
285};
286
287static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
288{
289 struct dev_dax *dev_dax = filp->private_data;
290 int rc, id;
291
292 dev_dbg(&dev_dax->dev, "trace\n");
293
294 /*
295 * We lock to check dax_dev liveness and will re-check at
296 * fault time.
297 */
298 id = dax_read_lock();
299 rc = check_vma(dev_dax, vma, __func__);
300 dax_read_unlock(id);
301 if (rc)
302 return rc;
303
304 vma->vm_ops = &dax_vm_ops;
305 vm_flags_set(vma, VM_HUGEPAGE);
306 return 0;
307}
308
309/* return an unmapped area aligned to the dax region specified alignment */
310static unsigned long dax_get_unmapped_area(struct file *filp,
311 unsigned long addr, unsigned long len, unsigned long pgoff,
312 unsigned long flags)
313{
314 unsigned long off, off_end, off_align, len_align, addr_align, align;
315 struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
316
317 if (!dev_dax || addr)
318 goto out;
319
320 align = dev_dax->align;
321 off = pgoff << PAGE_SHIFT;
322 off_end = off + len;
323 off_align = round_up(off, align);
324
325 if ((off_end <= off_align) || ((off_end - off_align) < align))
326 goto out;
327
328 len_align = len + align;
329 if ((off + len_align) < off)
330 goto out;
331
332 addr_align = current->mm->get_unmapped_area(filp, addr, len_align,
333 pgoff, flags);
334 if (!IS_ERR_VALUE(addr_align)) {
335 addr_align += (off - addr_align) & (align - 1);
336 return addr_align;
337 }
338 out:
339 return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
340}
341
342static const struct address_space_operations dev_dax_aops = {
343 .dirty_folio = noop_dirty_folio,
344};
345
346static int dax_open(struct inode *inode, struct file *filp)
347{
348 struct dax_device *dax_dev = inode_dax(inode);
349 struct inode *__dax_inode = dax_inode(dax_dev);
350 struct dev_dax *dev_dax = dax_get_private(dax_dev);
351
352 dev_dbg(&dev_dax->dev, "trace\n");
353 inode->i_mapping = __dax_inode->i_mapping;
354 inode->i_mapping->host = __dax_inode;
355 inode->i_mapping->a_ops = &dev_dax_aops;
356 filp->f_mapping = inode->i_mapping;
357 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
358 filp->f_sb_err = file_sample_sb_err(filp);
359 filp->private_data = dev_dax;
360 inode->i_flags = S_DAX;
361
362 return 0;
363}
364
365static int dax_release(struct inode *inode, struct file *filp)
366{
367 struct dev_dax *dev_dax = filp->private_data;
368
369 dev_dbg(&dev_dax->dev, "trace\n");
370 return 0;
371}
372
373static const struct file_operations dax_fops = {
374 .llseek = noop_llseek,
375 .owner = THIS_MODULE,
376 .open = dax_open,
377 .release = dax_release,
378 .get_unmapped_area = dax_get_unmapped_area,
379 .mmap = dax_mmap,
380 .mmap_supported_flags = MAP_SYNC,
381};
382
383static void dev_dax_cdev_del(void *cdev)
384{
385 cdev_del(cdev);
386}
387
388static void dev_dax_kill(void *dev_dax)
389{
390 kill_dev_dax(dev_dax);
391}
392
393static int dev_dax_probe(struct dev_dax *dev_dax)
394{
395 struct dax_device *dax_dev = dev_dax->dax_dev;
396 struct device *dev = &dev_dax->dev;
397 struct dev_pagemap *pgmap;
398 struct inode *inode;
399 struct cdev *cdev;
400 void *addr;
401 int rc, i;
402
403 if (static_dev_dax(dev_dax)) {
404 if (dev_dax->nr_range > 1) {
405 dev_warn(dev,
406 "static pgmap / multi-range device conflict\n");
407 return -EINVAL;
408 }
409
410 pgmap = dev_dax->pgmap;
411 } else {
412 if (dev_dax->pgmap) {
413 dev_warn(dev,
414 "dynamic-dax with pre-populated page map\n");
415 return -EINVAL;
416 }
417
418 pgmap = devm_kzalloc(dev,
419 struct_size(pgmap, ranges, dev_dax->nr_range - 1),
420 GFP_KERNEL);
421 if (!pgmap)
422 return -ENOMEM;
423
424 pgmap->nr_range = dev_dax->nr_range;
425 dev_dax->pgmap = pgmap;
426
427 for (i = 0; i < dev_dax->nr_range; i++) {
428 struct range *range = &dev_dax->ranges[i].range;
429 pgmap->ranges[i] = *range;
430 }
431 }
432
433 for (i = 0; i < dev_dax->nr_range; i++) {
434 struct range *range = &dev_dax->ranges[i].range;
435
436 if (!devm_request_mem_region(dev, range->start,
437 range_len(range), dev_name(dev))) {
438 dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve range\n",
439 i, range->start, range->end);
440 return -EBUSY;
441 }
442 }
443
444 pgmap->type = MEMORY_DEVICE_GENERIC;
445 if (dev_dax->align > PAGE_SIZE)
446 pgmap->vmemmap_shift =
447 order_base_2(dev_dax->align >> PAGE_SHIFT);
448 addr = devm_memremap_pages(dev, pgmap);
449 if (IS_ERR(addr))
450 return PTR_ERR(addr);
451
452 inode = dax_inode(dax_dev);
453 cdev = inode->i_cdev;
454 cdev_init(cdev, &dax_fops);
455 cdev->owner = dev->driver->owner;
456 cdev_set_parent(cdev, &dev->kobj);
457 rc = cdev_add(cdev, dev->devt, 1);
458 if (rc)
459 return rc;
460
461 rc = devm_add_action_or_reset(dev, dev_dax_cdev_del, cdev);
462 if (rc)
463 return rc;
464
465 run_dax(dax_dev);
466 return devm_add_action_or_reset(dev, dev_dax_kill, dev_dax);
467}
468
469static struct dax_device_driver device_dax_driver = {
470 .probe = dev_dax_probe,
471 .type = DAXDRV_DEVICE_TYPE,
472};
473
474static int __init dax_init(void)
475{
476 return dax_driver_register(&device_dax_driver);
477}
478
479static void __exit dax_exit(void)
480{
481 dax_driver_unregister(&device_dax_driver);
482}
483
484MODULE_AUTHOR("Intel Corporation");
485MODULE_LICENSE("GPL v2");
486module_init(dax_init);
487module_exit(dax_exit);
488MODULE_ALIAS_DAX_DEVICE(0);