2 * Copyright(c) 2016 - 2017 Intel Corporation. All rights reserved.
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of version 2 of the GNU General Public License as
6 * published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 #include <linux/pagemap.h>
14 #include <linux/module.h>
15 #include <linux/device.h>
16 #include <linux/pfn_t.h>
17 #include <linux/cdev.h>
18 #include <linux/slab.h>
19 #include <linux/dax.h>
22 #include <linux/mman.h>
23 #include "dax-private.h"
26 static struct class *dax_class;
29 * Rely on the fact that drvdata is set before the attributes are
30 * registered, and that the attributes are unregistered before drvdata
31 * is cleared to assume that drvdata is always valid.
33 static ssize_t id_show(struct device *dev,
34 struct device_attribute *attr, char *buf)
36 struct dax_region *dax_region = dev_get_drvdata(dev);
38 return sprintf(buf, "%d\n", dax_region->id);
40 static DEVICE_ATTR_RO(id);
42 static ssize_t region_size_show(struct device *dev,
43 struct device_attribute *attr, char *buf)
45 struct dax_region *dax_region = dev_get_drvdata(dev);
47 return sprintf(buf, "%llu\n", (unsigned long long)
48 resource_size(&dax_region->res));
50 static struct device_attribute dev_attr_region_size = __ATTR(size, 0444,
51 region_size_show, NULL);
53 static ssize_t align_show(struct device *dev,
54 struct device_attribute *attr, char *buf)
56 struct dax_region *dax_region = dev_get_drvdata(dev);
58 return sprintf(buf, "%u\n", dax_region->align);
60 static DEVICE_ATTR_RO(align);
62 static struct attribute *dax_region_attributes[] = {
63 &dev_attr_region_size.attr,
69 static const struct attribute_group dax_region_attribute_group = {
71 .attrs = dax_region_attributes,
74 static const struct attribute_group *dax_region_attribute_groups[] = {
75 &dax_region_attribute_group,
79 static void dax_region_free(struct kref *kref)
81 struct dax_region *dax_region;
83 dax_region = container_of(kref, struct dax_region, kref);
87 void dax_region_put(struct dax_region *dax_region)
89 kref_put(&dax_region->kref, dax_region_free);
91 EXPORT_SYMBOL_GPL(dax_region_put);
93 static void dax_region_unregister(void *region)
95 struct dax_region *dax_region = region;
97 sysfs_remove_groups(&dax_region->dev->kobj,
98 dax_region_attribute_groups);
99 dax_region_put(dax_region);
102 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
103 struct resource *res, unsigned int align, void *addr,
104 unsigned long pfn_flags)
106 struct dax_region *dax_region;
109 * The DAX core assumes that it can store its private data in
110 * parent->driver_data. This WARN is a reminder / safeguard for
111 * developers of device-dax drivers.
113 if (dev_get_drvdata(parent)) {
114 dev_WARN(parent, "dax core failed to setup private data\n");
118 if (!IS_ALIGNED(res->start, align)
119 || !IS_ALIGNED(resource_size(res), align))
122 dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
126 dev_set_drvdata(parent, dax_region);
127 memcpy(&dax_region->res, res, sizeof(*res));
128 dax_region->pfn_flags = pfn_flags;
129 kref_init(&dax_region->kref);
130 dax_region->id = region_id;
131 dax_region->align = align;
132 dax_region->dev = parent;
133 dax_region->base = addr;
134 if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) {
139 kref_get(&dax_region->kref);
140 if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
144 EXPORT_SYMBOL_GPL(alloc_dax_region);
146 static struct dev_dax *to_dev_dax(struct device *dev)
148 return container_of(dev, struct dev_dax, dev);
151 static ssize_t size_show(struct device *dev,
152 struct device_attribute *attr, char *buf)
154 struct dev_dax *dev_dax = to_dev_dax(dev);
155 unsigned long long size = 0;
158 for (i = 0; i < dev_dax->num_resources; i++)
159 size += resource_size(&dev_dax->res[i]);
161 return sprintf(buf, "%llu\n", size);
163 static DEVICE_ATTR_RO(size);
165 static struct attribute *dev_dax_attributes[] = {
170 static const struct attribute_group dev_dax_attribute_group = {
171 .attrs = dev_dax_attributes,
174 static const struct attribute_group *dax_attribute_groups[] = {
175 &dev_dax_attribute_group,
179 static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
182 struct dax_region *dax_region = dev_dax->region;
183 struct device *dev = &dev_dax->dev;
186 if (!dax_alive(dev_dax->dax_dev))
189 /* prevent private mappings from being established */
190 if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
191 dev_info_ratelimited(dev,
192 "%s: %s: fail, attempted private mapping\n",
193 current->comm, func);
197 mask = dax_region->align - 1;
198 if (vma->vm_start & mask || vma->vm_end & mask) {
199 dev_info_ratelimited(dev,
200 "%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
201 current->comm, func, vma->vm_start, vma->vm_end,
206 if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV
207 && (vma->vm_flags & VM_DONTCOPY) == 0) {
208 dev_info_ratelimited(dev,
209 "%s: %s: fail, dax range requires MADV_DONTFORK\n",
210 current->comm, func);
214 if (!vma_is_dax(vma)) {
215 dev_info_ratelimited(dev,
216 "%s: %s: fail, vma is not DAX capable\n",
217 current->comm, func);
224 /* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
225 __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
228 struct resource *res;
229 /* gcc-4.6.3-nolibc for i386 complains that this is uninitialized */
230 phys_addr_t uninitialized_var(phys);
233 for (i = 0; i < dev_dax->num_resources; i++) {
234 res = &dev_dax->res[i];
235 phys = pgoff * PAGE_SIZE + res->start;
236 if (phys >= res->start && phys <= res->end)
238 pgoff -= PHYS_PFN(resource_size(res));
241 if (i < dev_dax->num_resources) {
242 res = &dev_dax->res[i];
243 if (phys + size - 1 <= res->end)
250 static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
251 struct vm_fault *vmf, pfn_t *pfn)
253 struct device *dev = &dev_dax->dev;
254 struct dax_region *dax_region;
256 unsigned int fault_size = PAGE_SIZE;
258 if (check_vma(dev_dax, vmf->vma, __func__))
259 return VM_FAULT_SIGBUS;
261 dax_region = dev_dax->region;
262 if (dax_region->align > PAGE_SIZE) {
263 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
264 dax_region->align, fault_size);
265 return VM_FAULT_SIGBUS;
268 if (fault_size != dax_region->align)
269 return VM_FAULT_SIGBUS;
271 phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
273 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
274 return VM_FAULT_SIGBUS;
277 *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
279 return vmf_insert_mixed(vmf->vma, vmf->address, *pfn);
282 static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
283 struct vm_fault *vmf, pfn_t *pfn)
285 unsigned long pmd_addr = vmf->address & PMD_MASK;
286 struct device *dev = &dev_dax->dev;
287 struct dax_region *dax_region;
290 unsigned int fault_size = PMD_SIZE;
292 if (check_vma(dev_dax, vmf->vma, __func__))
293 return VM_FAULT_SIGBUS;
295 dax_region = dev_dax->region;
296 if (dax_region->align > PMD_SIZE) {
297 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
298 dax_region->align, fault_size);
299 return VM_FAULT_SIGBUS;
302 /* dax pmd mappings require pfn_t_devmap() */
303 if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
304 dev_dbg(dev, "region lacks devmap flags\n");
305 return VM_FAULT_SIGBUS;
308 if (fault_size < dax_region->align)
309 return VM_FAULT_SIGBUS;
310 else if (fault_size > dax_region->align)
311 return VM_FAULT_FALLBACK;
313 /* if we are outside of the VMA */
314 if (pmd_addr < vmf->vma->vm_start ||
315 (pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
316 return VM_FAULT_SIGBUS;
318 pgoff = linear_page_index(vmf->vma, pmd_addr);
319 phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
321 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
322 return VM_FAULT_SIGBUS;
325 *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
327 return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, *pfn,
328 vmf->flags & FAULT_FLAG_WRITE);
331 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
332 static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
333 struct vm_fault *vmf, pfn_t *pfn)
335 unsigned long pud_addr = vmf->address & PUD_MASK;
336 struct device *dev = &dev_dax->dev;
337 struct dax_region *dax_region;
340 unsigned int fault_size = PUD_SIZE;
343 if (check_vma(dev_dax, vmf->vma, __func__))
344 return VM_FAULT_SIGBUS;
346 dax_region = dev_dax->region;
347 if (dax_region->align > PUD_SIZE) {
348 dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
349 dax_region->align, fault_size);
350 return VM_FAULT_SIGBUS;
353 /* dax pud mappings require pfn_t_devmap() */
354 if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
355 dev_dbg(dev, "region lacks devmap flags\n");
356 return VM_FAULT_SIGBUS;
359 if (fault_size < dax_region->align)
360 return VM_FAULT_SIGBUS;
361 else if (fault_size > dax_region->align)
362 return VM_FAULT_FALLBACK;
364 /* if we are outside of the VMA */
365 if (pud_addr < vmf->vma->vm_start ||
366 (pud_addr + PUD_SIZE) > vmf->vma->vm_end)
367 return VM_FAULT_SIGBUS;
369 pgoff = linear_page_index(vmf->vma, pud_addr);
370 phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
372 dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
373 return VM_FAULT_SIGBUS;
376 *pfn = phys_to_pfn_t(phys, dax_region->pfn_flags);
378 return vmf_insert_pfn_pud(vmf->vma, vmf->address, vmf->pud, *pfn,
379 vmf->flags & FAULT_FLAG_WRITE);
382 static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
383 struct vm_fault *vmf, pfn_t *pfn)
385 return VM_FAULT_FALLBACK;
387 #endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
389 static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
390 enum page_entry_size pe_size)
392 struct file *filp = vmf->vma->vm_file;
393 unsigned long fault_size;
394 vm_fault_t rc = VM_FAULT_SIGBUS;
397 struct dev_dax *dev_dax = filp->private_data;
399 dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
400 (vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
401 vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
403 id = dax_read_lock();
406 fault_size = PAGE_SIZE;
407 rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn);
410 fault_size = PMD_SIZE;
411 rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn);
414 fault_size = PUD_SIZE;
415 rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn);
418 rc = VM_FAULT_SIGBUS;
421 if (rc == VM_FAULT_NOPAGE) {
426 * In the device-dax case the only possibility for a
427 * VM_FAULT_NOPAGE result is when device-dax capacity is
428 * mapped. No need to consider the zero page, or racing
429 * conflicting mappings.
431 pgoff = linear_page_index(vmf->vma, vmf->address
432 & ~(fault_size - 1));
433 for (i = 0; i < fault_size / PAGE_SIZE; i++) {
436 page = pfn_to_page(pfn_t_to_pfn(pfn) + i);
439 page->mapping = filp->f_mapping;
440 page->index = pgoff + i;
448 static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
450 return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
453 static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr)
455 struct file *filp = vma->vm_file;
456 struct dev_dax *dev_dax = filp->private_data;
457 struct dax_region *dax_region = dev_dax->region;
459 if (!IS_ALIGNED(addr, dax_region->align))
464 static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
466 struct file *filp = vma->vm_file;
467 struct dev_dax *dev_dax = filp->private_data;
468 struct dax_region *dax_region = dev_dax->region;
470 return dax_region->align;
473 static const struct vm_operations_struct dax_vm_ops = {
474 .fault = dev_dax_fault,
475 .huge_fault = dev_dax_huge_fault,
476 .split = dev_dax_split,
477 .pagesize = dev_dax_pagesize,
480 static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
482 struct dev_dax *dev_dax = filp->private_data;
485 dev_dbg(&dev_dax->dev, "trace\n");
488 * We lock to check dax_dev liveness and will re-check at
491 id = dax_read_lock();
492 rc = check_vma(dev_dax, vma, __func__);
497 vma->vm_ops = &dax_vm_ops;
498 vma->vm_flags |= VM_HUGEPAGE;
502 /* return an unmapped area aligned to the dax region specified alignment */
503 static unsigned long dax_get_unmapped_area(struct file *filp,
504 unsigned long addr, unsigned long len, unsigned long pgoff,
507 unsigned long off, off_end, off_align, len_align, addr_align, align;
508 struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
509 struct dax_region *dax_region;
511 if (!dev_dax || addr)
514 dax_region = dev_dax->region;
515 align = dax_region->align;
516 off = pgoff << PAGE_SHIFT;
518 off_align = round_up(off, align);
520 if ((off_end <= off_align) || ((off_end - off_align) < align))
523 len_align = len + align;
524 if ((off + len_align) < off)
527 addr_align = current->mm->get_unmapped_area(filp, addr, len_align,
529 if (!IS_ERR_VALUE(addr_align)) {
530 addr_align += (off - addr_align) & (align - 1);
534 return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
537 static const struct address_space_operations dev_dax_aops = {
538 .set_page_dirty = noop_set_page_dirty,
539 .invalidatepage = noop_invalidatepage,
542 static int dax_open(struct inode *inode, struct file *filp)
544 struct dax_device *dax_dev = inode_dax(inode);
545 struct inode *__dax_inode = dax_inode(dax_dev);
546 struct dev_dax *dev_dax = dax_get_private(dax_dev);
548 dev_dbg(&dev_dax->dev, "trace\n");
549 inode->i_mapping = __dax_inode->i_mapping;
550 inode->i_mapping->host = __dax_inode;
551 inode->i_mapping->a_ops = &dev_dax_aops;
552 filp->f_mapping = inode->i_mapping;
553 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
554 filp->private_data = dev_dax;
555 inode->i_flags = S_DAX;
560 static int dax_release(struct inode *inode, struct file *filp)
562 struct dev_dax *dev_dax = filp->private_data;
564 dev_dbg(&dev_dax->dev, "trace\n");
568 static const struct file_operations dax_fops = {
569 .llseek = noop_llseek,
570 .owner = THIS_MODULE,
572 .release = dax_release,
573 .get_unmapped_area = dax_get_unmapped_area,
575 .mmap_supported_flags = MAP_SYNC,
578 static void dev_dax_release(struct device *dev)
580 struct dev_dax *dev_dax = to_dev_dax(dev);
581 struct dax_region *dax_region = dev_dax->region;
582 struct dax_device *dax_dev = dev_dax->dax_dev;
584 dax_region_put(dax_region);
589 static void kill_dev_dax(struct dev_dax *dev_dax)
591 struct dax_device *dax_dev = dev_dax->dax_dev;
592 struct inode *inode = dax_inode(dax_dev);
595 unmap_mapping_range(inode->i_mapping, 0, 0, 1);
598 static void unregister_dev_dax(void *dev)
600 struct dev_dax *dev_dax = to_dev_dax(dev);
601 struct dax_device *dax_dev = dev_dax->dax_dev;
602 struct inode *inode = dax_inode(dax_dev);
603 struct cdev *cdev = inode->i_cdev;
605 dev_dbg(dev, "trace\n");
607 kill_dev_dax(dev_dax);
608 cdev_device_del(cdev, dev);
612 struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
613 int id, struct resource *res, int count)
615 struct device *parent = dax_region->dev;
616 struct dax_device *dax_dev;
617 struct dev_dax *dev_dax;
624 return ERR_PTR(-EINVAL);
626 dev_dax = kzalloc(struct_size(dev_dax, res, count), GFP_KERNEL);
628 return ERR_PTR(-ENOMEM);
630 for (i = 0; i < count; i++) {
631 if (!IS_ALIGNED(res[i].start, dax_region->align)
632 || !IS_ALIGNED(resource_size(&res[i]),
633 dax_region->align)) {
637 dev_dax->res[i].start = res[i].start;
638 dev_dax->res[i].end = res[i].end;
645 * No 'host' or dax_operations since there is no access to this
646 * device outside of mmap of the resulting character device.
648 dax_dev = alloc_dax(dev_dax, NULL, NULL);
654 /* from here on we're committed to teardown via dax_dev_release() */
656 device_initialize(dev);
658 inode = dax_inode(dax_dev);
659 cdev = inode->i_cdev;
660 cdev_init(cdev, &dax_fops);
661 cdev->owner = parent->driver->owner;
663 dev_dax->num_resources = count;
664 dev_dax->dax_dev = dax_dev;
665 dev_dax->region = dax_region;
666 kref_get(&dax_region->kref);
668 dev->devt = inode->i_rdev;
669 dev->class = dax_class;
670 dev->parent = parent;
671 dev->groups = dax_attribute_groups;
672 dev->release = dev_dax_release;
673 dev_set_name(dev, "dax%d.%d", dax_region->id, id);
675 rc = cdev_device_add(cdev, dev);
677 kill_dev_dax(dev_dax);
682 rc = devm_add_action_or_reset(dax_region->dev, unregister_dev_dax, dev);
693 EXPORT_SYMBOL_GPL(devm_create_dev_dax);
695 static int __init dax_init(void)
697 dax_class = class_create(THIS_MODULE, "dax");
698 return PTR_ERR_OR_ZERO(dax_class);
701 static void __exit dax_exit(void)
703 class_destroy(dax_class);
706 MODULE_AUTHOR("Intel Corporation");
707 MODULE_LICENSE("GPL v2");
708 subsys_initcall(dax_init);
709 module_exit(dax_exit);