Loading...
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 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);