[linux-2.6-block.git] / drivers / dax / device.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016-2018 Intel Corporation. All rights reserved. */
#include <linux/memremap.h>
#include <linux/pagemap.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/pfn_t.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/dax.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include "dax-private.h"
#include "bus.h"

static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
		const char *func)
{
	struct device *dev = &dev_dax->dev;
	unsigned long mask;

	if (!dax_alive(dev_dax->dax_dev))
		return -ENXIO;

	/* prevent private mappings from being established */
	if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
		dev_info_ratelimited(dev,
				"%s: %s: fail, attempted private mapping\n",
				current->comm, func);
		return -EINVAL;
	}

	mask = dev_dax->align - 1;
	if (vma->vm_start & mask || vma->vm_end & mask) {
		dev_info_ratelimited(dev,
				"%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
				current->comm, func, vma->vm_start, vma->vm_end,
				mask);
		return -EINVAL;
	}

	if (!vma_is_dax(vma)) {
		dev_info_ratelimited(dev,
				"%s: %s: fail, vma is not DAX capable\n",
				current->comm, func);
		return -EINVAL;
	}

	return 0;
}

/* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
__weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
		unsigned long size)
{
	int i;

	for (i = 0; i < dev_dax->nr_range; i++) {
		struct dev_dax_range *dax_range = &dev_dax->ranges[i];
		struct range *range = &dax_range->range;
		unsigned long long pgoff_end;
		phys_addr_t phys;

		pgoff_end = dax_range->pgoff + PHYS_PFN(range_len(range)) - 1;
		if (pgoff < dax_range->pgoff || pgoff > pgoff_end)
			continue;
		phys = PFN_PHYS(pgoff - dax_range->pgoff) + range->start;
		if (phys + size - 1 <= range->end)
			return phys;
		break;
	}
	return -1;
}

static void dax_set_mapping(struct vm_fault *vmf, pfn_t pfn,
			      unsigned long fault_size)
{
	unsigned long i, nr_pages = fault_size / PAGE_SIZE;
	struct file *filp = vmf->vma->vm_file;
	struct dev_dax *dev_dax = filp->private_data;
	pgoff_t pgoff;

	/* mapping is only set on the head */
	if (dev_dax->pgmap->vmemmap_shift)
		nr_pages = 1;

	pgoff = linear_page_index(vmf->vma,
			ALIGN_DOWN(vmf->address, fault_size));

	for (i = 0; i < nr_pages; i++) {
		struct folio *folio = pfn_folio(pfn_t_to_pfn(pfn) + i);

		if (folio->mapping)
			continue;

		folio->mapping = filp->f_mapping;
		folio->index = pgoff + i;
	}
}

static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
				struct vm_fault *vmf)
{
	struct device *dev = &dev_dax->dev;
	phys_addr_t phys;
	pfn_t pfn;
	unsigned int fault_size = PAGE_SIZE;

	if (check_vma(dev_dax, vmf->vma, __func__))
		return VM_FAULT_SIGBUS;

	if (dev_dax->align > PAGE_SIZE) {
		dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
			dev_dax->align, fault_size);
		return VM_FAULT_SIGBUS;
	}

	if (fault_size != dev_dax->align)
		return VM_FAULT_SIGBUS;

	phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
	if (phys == -1) {
		dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
		return VM_FAULT_SIGBUS;
	}

	pfn = phys_to_pfn_t(phys, 0);

	dax_set_mapping(vmf, pfn, fault_size);

	return vmf_insert_page_mkwrite(vmf, pfn_t_to_page(pfn),
					vmf->flags & FAULT_FLAG_WRITE);
}

static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
				struct vm_fault *vmf)
{
	unsigned long pmd_addr = vmf->address & PMD_MASK;
	struct device *dev = &dev_dax->dev;
	phys_addr_t phys;
	pgoff_t pgoff;
	pfn_t pfn;
	unsigned int fault_size = PMD_SIZE;

	if (check_vma(dev_dax, vmf->vma, __func__))
		return VM_FAULT_SIGBUS;

	if (dev_dax->align > PMD_SIZE) {
		dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
			dev_dax->align, fault_size);
		return VM_FAULT_SIGBUS;
	}

	if (fault_size < dev_dax->align)
		return VM_FAULT_SIGBUS;
	else if (fault_size > dev_dax->align)
		return VM_FAULT_FALLBACK;

	/* if we are outside of the VMA */
	if (pmd_addr < vmf->vma->vm_start ||
			(pmd_addr + PMD_SIZE) > vmf->vma->vm_end)
		return VM_FAULT_SIGBUS;

	pgoff = linear_page_index(vmf->vma, pmd_addr);
	phys = dax_pgoff_to_phys(dev_dax, pgoff, PMD_SIZE);
	if (phys == -1) {
		dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
		return VM_FAULT_SIGBUS;
	}

	pfn = phys_to_pfn_t(phys, 0);

	dax_set_mapping(vmf, pfn, fault_size);

	return vmf_insert_folio_pmd(vmf, page_folio(pfn_t_to_page(pfn)),
				vmf->flags & FAULT_FLAG_WRITE);
}

#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
				struct vm_fault *vmf)
{
	unsigned long pud_addr = vmf->address & PUD_MASK;
	struct device *dev = &dev_dax->dev;
	phys_addr_t phys;
	pgoff_t pgoff;
	pfn_t pfn;
	unsigned int fault_size = PUD_SIZE;


	if (check_vma(dev_dax, vmf->vma, __func__))
		return VM_FAULT_SIGBUS;

	if (dev_dax->align > PUD_SIZE) {
		dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
			dev_dax->align, fault_size);
		return VM_FAULT_SIGBUS;
	}

	if (fault_size < dev_dax->align)
		return VM_FAULT_SIGBUS;
	else if (fault_size > dev_dax->align)
		return VM_FAULT_FALLBACK;

	/* if we are outside of the VMA */
	if (pud_addr < vmf->vma->vm_start ||
			(pud_addr + PUD_SIZE) > vmf->vma->vm_end)
		return VM_FAULT_SIGBUS;

	pgoff = linear_page_index(vmf->vma, pud_addr);
	phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
	if (phys == -1) {
		dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
		return VM_FAULT_SIGBUS;
	}

	pfn = phys_to_pfn_t(phys, 0);

	dax_set_mapping(vmf, pfn, fault_size);

	return vmf_insert_folio_pud(vmf, page_folio(pfn_t_to_page(pfn)),
				vmf->flags & FAULT_FLAG_WRITE);
}
#else
static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
				struct vm_fault *vmf)
{
	return VM_FAULT_FALLBACK;
}
#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */

static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, unsigned int order)
{
	struct file *filp = vmf->vma->vm_file;
	vm_fault_t rc = VM_FAULT_SIGBUS;
	int id;
	struct dev_dax *dev_dax = filp->private_data;

	dev_dbg(&dev_dax->dev, "%s: op=%s addr=%#lx order=%d\n", current->comm,
		(vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
		vmf->address & ~((1UL << (order + PAGE_SHIFT)) - 1), order);

	id = dax_read_lock();
	if (order == 0)
		rc = __dev_dax_pte_fault(dev_dax, vmf);
	else if (order == PMD_ORDER)
		rc = __dev_dax_pmd_fault(dev_dax, vmf);
	else if (order == PUD_ORDER)
		rc = __dev_dax_pud_fault(dev_dax, vmf);
	else
		rc = VM_FAULT_SIGBUS;

	dax_read_unlock(id);

	return rc;
}

static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
{
	return dev_dax_huge_fault(vmf, 0);
}

static int dev_dax_may_split(struct vm_area_struct *vma, unsigned long addr)
{
	struct file *filp = vma->vm_file;
	struct dev_dax *dev_dax = filp->private_data;

	if (!IS_ALIGNED(addr, dev_dax->align))
		return -EINVAL;
	return 0;
}

static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
{
	struct file *filp = vma->vm_file;
	struct dev_dax *dev_dax = filp->private_data;

	return dev_dax->align;
}

static const struct vm_operations_struct dax_vm_ops = {
	.fault = dev_dax_fault,
	.huge_fault = dev_dax_huge_fault,
	.may_split = dev_dax_may_split,
	.pagesize = dev_dax_pagesize,
};

static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
{
	struct dev_dax *dev_dax = filp->private_data;
	int rc, id;

	dev_dbg(&dev_dax->dev, "trace\n");

	/*
	 * We lock to check dax_dev liveness and will re-check at
	 * fault time.
	 */
	id = dax_read_lock();
	rc = check_vma(dev_dax, vma, __func__);
	dax_read_unlock(id);
	if (rc)
		return rc;

	vma->vm_ops = &dax_vm_ops;
	vm_flags_set(vma, VM_HUGEPAGE);
	return 0;
}

/* return an unmapped area aligned to the dax region specified alignment */
static unsigned long dax_get_unmapped_area(struct file *filp,
		unsigned long addr, unsigned long len, unsigned long pgoff,
		unsigned long flags)
{
	unsigned long off, off_end, off_align, len_align, addr_align, align;
	struct dev_dax *dev_dax = filp ? filp->private_data : NULL;

	if (!dev_dax || addr)
		goto out;

	align = dev_dax->align;
	off = pgoff << PAGE_SHIFT;
	off_end = off + len;
	off_align = round_up(off, align);

	if ((off_end <= off_align) || ((off_end - off_align) < align))
		goto out;

	len_align = len + align;
	if ((off + len_align) < off)
		goto out;

	addr_align = mm_get_unmapped_area(current->mm, filp, addr, len_align,
					  pgoff, flags);
	if (!IS_ERR_VALUE(addr_align)) {
		addr_align += (off - addr_align) & (align - 1);
		return addr_align;
	}
 out:
	return mm_get_unmapped_area(current->mm, filp, addr, len, pgoff, flags);
}

static const struct address_space_operations dev_dax_aops = {
	.dirty_folio	= noop_dirty_folio,
};

static int dax_open(struct inode *inode, struct file *filp)
{
	struct dax_device *dax_dev = inode_dax(inode);
	struct inode *__dax_inode = dax_inode(dax_dev);
	struct dev_dax *dev_dax = dax_get_private(dax_dev);

	dev_dbg(&dev_dax->dev, "trace\n");
	inode->i_mapping = __dax_inode->i_mapping;
	inode->i_mapping->host = __dax_inode;
	inode->i_mapping->a_ops = &dev_dax_aops;
	filp->f_mapping = inode->i_mapping;
	filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
	filp->f_sb_err = file_sample_sb_err(filp);
	filp->private_data = dev_dax;
	inode->i_flags = S_DAX;

	return 0;
}

static int dax_release(struct inode *inode, struct file *filp)
{
	struct dev_dax *dev_dax = filp->private_data;

	dev_dbg(&dev_dax->dev, "trace\n");
	return 0;
}

static const struct file_operations dax_fops = {
	.llseek = noop_llseek,
	.owner = THIS_MODULE,
	.open = dax_open,
	.release = dax_release,
	.get_unmapped_area = dax_get_unmapped_area,
	.mmap = dax_mmap,
	.fop_flags = FOP_MMAP_SYNC,
};

static void dev_dax_cdev_del(void *cdev)
{
	cdev_del(cdev);
}

static void dev_dax_kill(void *dev_dax)
{
	kill_dev_dax(dev_dax);
}

static int dev_dax_probe(struct dev_dax *dev_dax)
{
	struct dax_device *dax_dev = dev_dax->dax_dev;
	struct device *dev = &dev_dax->dev;
	struct dev_pagemap *pgmap;
	struct inode *inode;
	struct cdev *cdev;
	void *addr;
	int rc, i;

	if (static_dev_dax(dev_dax))  {
		if (dev_dax->nr_range > 1) {
			dev_warn(dev,
				"static pgmap / multi-range device conflict\n");
			return -EINVAL;
		}

		pgmap = dev_dax->pgmap;
	} else {
		if (dev_dax->pgmap) {
			dev_warn(dev,
				 "dynamic-dax with pre-populated page map\n");
			return -EINVAL;
		}

		pgmap = devm_kzalloc(dev,
                       struct_size(pgmap, ranges, dev_dax->nr_range - 1),
                       GFP_KERNEL);
		if (!pgmap)
			return -ENOMEM;

		pgmap->nr_range = dev_dax->nr_range;
		dev_dax->pgmap = pgmap;

		for (i = 0; i < dev_dax->nr_range; i++) {
			struct range *range = &dev_dax->ranges[i].range;
			pgmap->ranges[i] = *range;
		}
	}

	for (i = 0; i < dev_dax->nr_range; i++) {
		struct range *range = &dev_dax->ranges[i].range;

		if (!devm_request_mem_region(dev, range->start,
					range_len(range), dev_name(dev))) {
			dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve range\n",
					i, range->start, range->end);
			return -EBUSY;
		}
	}

	pgmap->type = MEMORY_DEVICE_GENERIC;
	if (dev_dax->align > PAGE_SIZE)
		pgmap->vmemmap_shift =
			order_base_2(dev_dax->align >> PAGE_SHIFT);
	addr = devm_memremap_pages(dev, pgmap);
	if (IS_ERR(addr))
		return PTR_ERR(addr);

	inode = dax_inode(dax_dev);
	cdev = inode->i_cdev;
	cdev_init(cdev, &dax_fops);
	cdev->owner = dev->driver->owner;
	cdev_set_parent(cdev, &dev->kobj);
	rc = cdev_add(cdev, dev->devt, 1);
	if (rc)
		return rc;

	rc = devm_add_action_or_reset(dev, dev_dax_cdev_del, cdev);
	if (rc)
		return rc;

	run_dax(dax_dev);
	return devm_add_action_or_reset(dev, dev_dax_kill, dev_dax);
}

static struct dax_device_driver device_dax_driver = {
	.probe = dev_dax_probe,
	.type = DAXDRV_DEVICE_TYPE,
};

static int __init dax_init(void)
{
	return dax_driver_register(&device_dax_driver);
}

static void __exit dax_exit(void)
{
	dax_driver_unregister(&device_dax_driver);
}

MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("Device DAX: direct access device driver");
MODULE_LICENSE("GPL v2");
module_init(dax_init);
module_exit(dax_exit);
MODULE_ALIAS_DAX_DEVICE(0);
Commit	Line	Data
	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
	17	static 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
	76	static 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_DOWN(vmf->address, fault_size));
	90
	91	for (i = 0; i < nr_pages; i++) {
	92	struct folio *folio = pfn_folio(pfn_t_to_pfn(pfn) + i);
	93
	94	if (folio->mapping)
	95	continue;
	96
	97	folio->mapping = filp->f_mapping;
	98	folio->index = pgoff + i;
	99	}
	100	}
	101
	102	static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
	103	struct vm_fault *vmf)
	104	{
	105	struct device *dev = &dev_dax->dev;
	106	phys_addr_t phys;
	107	pfn_t pfn;
	108	unsigned int fault_size = PAGE_SIZE;
	109
	110	if (check_vma(dev_dax, vmf->vma, __func__))
	111	return VM_FAULT_SIGBUS;
	112
	113	if (dev_dax->align > PAGE_SIZE) {
	114	dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
	115	dev_dax->align, fault_size);
	116	return VM_FAULT_SIGBUS;
	117	}
	118
	119	if (fault_size != dev_dax->align)
	120	return VM_FAULT_SIGBUS;
	121
	122	phys = dax_pgoff_to_phys(dev_dax, vmf->pgoff, PAGE_SIZE);
	123	if (phys == -1) {
	124	dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", vmf->pgoff);
	125	return VM_FAULT_SIGBUS;
	126	}
	127
	128	pfn = phys_to_pfn_t(phys, 0);
	129
	130	dax_set_mapping(vmf, pfn, fault_size);
	131
	132	return vmf_insert_page_mkwrite(vmf, pfn_t_to_page(pfn),
	133	vmf->flags & FAULT_FLAG_WRITE);
	134	}
	135
	136	static 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, 0);
	173
	174	dax_set_mapping(vmf, pfn, fault_size);
	175
	176	return vmf_insert_folio_pmd(vmf, page_folio(pfn_t_to_page(pfn)),
	177	vmf->flags & FAULT_FLAG_WRITE);
	178	}
	179
	180	#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
	181	static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
	182	struct vm_fault *vmf)
	183	{
	184	unsigned long pud_addr = vmf->address & PUD_MASK;
	185	struct device *dev = &dev_dax->dev;
	186	phys_addr_t phys;
	187	pgoff_t pgoff;
	188	pfn_t pfn;
	189	unsigned int fault_size = PUD_SIZE;
	190
	191
	192	if (check_vma(dev_dax, vmf->vma, __func__))
	193	return VM_FAULT_SIGBUS;
	194
	195	if (dev_dax->align > PUD_SIZE) {
	196	dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
	197	dev_dax->align, fault_size);
	198	return VM_FAULT_SIGBUS;
	199	}
	200
	201	if (fault_size < dev_dax->align)
	202	return VM_FAULT_SIGBUS;
	203	else if (fault_size > dev_dax->align)
	204	return VM_FAULT_FALLBACK;
	205
	206	/* if we are outside of the VMA */
	207	if (pud_addr < vmf->vma->vm_start \|\|
	208	(pud_addr + PUD_SIZE) > vmf->vma->vm_end)
	209	return VM_FAULT_SIGBUS;
	210
	211	pgoff = linear_page_index(vmf->vma, pud_addr);
	212	phys = dax_pgoff_to_phys(dev_dax, pgoff, PUD_SIZE);
	213	if (phys == -1) {
	214	dev_dbg(dev, "pgoff_to_phys(%#lx) failed\n", pgoff);
	215	return VM_FAULT_SIGBUS;
	216	}
	217
	218	pfn = phys_to_pfn_t(phys, 0);
	219
	220	dax_set_mapping(vmf, pfn, fault_size);
	221
	222	return vmf_insert_folio_pud(vmf, page_folio(pfn_t_to_page(pfn)),
	223	vmf->flags & FAULT_FLAG_WRITE);
	224	}
	225	#else
	226	static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
	227	struct vm_fault *vmf)
	228	{
	229	return VM_FAULT_FALLBACK;
	230	}
	231	#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
	232
	233	static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf, unsigned int order)
	234	{
	235	struct file *filp = vmf->vma->vm_file;
	236	vm_fault_t rc = VM_FAULT_SIGBUS;
	237	int id;
	238	struct dev_dax *dev_dax = filp->private_data;
	239
	240	dev_dbg(&dev_dax->dev, "%s: op=%s addr=%#lx order=%d\n", current->comm,
	241	(vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
	242	vmf->address & ~((1UL << (order + PAGE_SHIFT)) - 1), order);
	243
	244	id = dax_read_lock();
	245	if (order == 0)
	246	rc = __dev_dax_pte_fault(dev_dax, vmf);
	247	else if (order == PMD_ORDER)
	248	rc = __dev_dax_pmd_fault(dev_dax, vmf);
	249	else if (order == PUD_ORDER)
	250	rc = __dev_dax_pud_fault(dev_dax, vmf);
	251	else
	252	rc = VM_FAULT_SIGBUS;
	253
	254	dax_read_unlock(id);
	255
	256	return rc;
	257	}
	258
	259	static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
	260	{
	261	return dev_dax_huge_fault(vmf, 0);
	262	}
	263
	264	static int dev_dax_may_split(struct vm_area_struct *vma, unsigned long addr)
	265	{
	266	struct file *filp = vma->vm_file;
	267	struct dev_dax *dev_dax = filp->private_data;
	268
	269	if (!IS_ALIGNED(addr, dev_dax->align))
	270	return -EINVAL;
	271	return 0;
	272	}
	273
	274	static unsigned long dev_dax_pagesize(struct vm_area_struct *vma)
	275	{
	276	struct file *filp = vma->vm_file;
	277	struct dev_dax *dev_dax = filp->private_data;
	278
	279	return dev_dax->align;
	280	}
	281
	282	static const struct vm_operations_struct dax_vm_ops = {
	283	.fault = dev_dax_fault,
	284	.huge_fault = dev_dax_huge_fault,
	285	.may_split = dev_dax_may_split,
	286	.pagesize = dev_dax_pagesize,
	287	};
	288
	289	static int dax_mmap(struct file filp, struct vm_area_struct vma)
	290	{
	291	struct dev_dax *dev_dax = filp->private_data;
	292	int rc, id;
	293
	294	dev_dbg(&dev_dax->dev, "trace\n");
	295
	296	/*
	297	* We lock to check dax_dev liveness and will re-check at
	298	* fault time.
	299	*/
	300	id = dax_read_lock();
	301	rc = check_vma(dev_dax, vma, __func__);
	302	dax_read_unlock(id);
	303	if (rc)
	304	return rc;
	305
	306	vma->vm_ops = &dax_vm_ops;
	307	vm_flags_set(vma, VM_HUGEPAGE);
	308	return 0;
	309	}
	310
	311	/* return an unmapped area aligned to the dax region specified alignment */
	312	static unsigned long dax_get_unmapped_area(struct file *filp,
	313	unsigned long addr, unsigned long len, unsigned long pgoff,
	314	unsigned long flags)
	315	{
	316	unsigned long off, off_end, off_align, len_align, addr_align, align;
	317	struct dev_dax *dev_dax = filp ? filp->private_data : NULL;
	318
	319	if (!dev_dax \|\| addr)
	320	goto out;
	321
	322	align = dev_dax->align;
	323	off = pgoff << PAGE_SHIFT;
	324	off_end = off + len;
	325	off_align = round_up(off, align);
	326
	327	if ((off_end <= off_align) \|\| ((off_end - off_align) < align))
	328	goto out;
	329
	330	len_align = len + align;
	331	if ((off + len_align) < off)
	332	goto out;
	333
	334	addr_align = mm_get_unmapped_area(current->mm, filp, addr, len_align,
	335	pgoff, flags);
	336	if (!IS_ERR_VALUE(addr_align)) {
	337	addr_align += (off - addr_align) & (align - 1);
	338	return addr_align;
	339	}
	340	out:
	341	return mm_get_unmapped_area(current->mm, filp, addr, len, pgoff, flags);
	342	}
	343
	344	static const struct address_space_operations dev_dax_aops = {
	345	.dirty_folio = noop_dirty_folio,
	346	};
	347
	348	static int dax_open(struct inode inode, struct file filp)
	349	{
	350	struct dax_device *dax_dev = inode_dax(inode);
	351	struct inode *__dax_inode = dax_inode(dax_dev);
	352	struct dev_dax *dev_dax = dax_get_private(dax_dev);
	353
	354	dev_dbg(&dev_dax->dev, "trace\n");
	355	inode->i_mapping = __dax_inode->i_mapping;
	356	inode->i_mapping->host = __dax_inode;
	357	inode->i_mapping->a_ops = &dev_dax_aops;
	358	filp->f_mapping = inode->i_mapping;
	359	filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
	360	filp->f_sb_err = file_sample_sb_err(filp);
	361	filp->private_data = dev_dax;
	362	inode->i_flags = S_DAX;
	363
	364	return 0;
	365	}
	366
	367	static int dax_release(struct inode inode, struct file filp)
	368	{
	369	struct dev_dax *dev_dax = filp->private_data;
	370
	371	dev_dbg(&dev_dax->dev, "trace\n");
	372	return 0;
	373	}
	374
	375	static const struct file_operations dax_fops = {
	376	.llseek = noop_llseek,
	377	.owner = THIS_MODULE,
	378	.open = dax_open,
	379	.release = dax_release,
	380	.get_unmapped_area = dax_get_unmapped_area,
	381	.mmap = dax_mmap,
	382	.fop_flags = FOP_MMAP_SYNC,
	383	};
	384
	385	static void dev_dax_cdev_del(void *cdev)
	386	{
	387	cdev_del(cdev);
	388	}
	389
	390	static void dev_dax_kill(void *dev_dax)
	391	{
	392	kill_dev_dax(dev_dax);
	393	}
	394
	395	static int dev_dax_probe(struct dev_dax *dev_dax)
	396	{
	397	struct dax_device *dax_dev = dev_dax->dax_dev;
	398	struct device *dev = &dev_dax->dev;
	399	struct dev_pagemap *pgmap;
	400	struct inode *inode;
	401	struct cdev *cdev;
	402	void *addr;
	403	int rc, i;
	404
	405	if (static_dev_dax(dev_dax)) {
	406	if (dev_dax->nr_range > 1) {
	407	dev_warn(dev,
	408	"static pgmap / multi-range device conflict\n");
	409	return -EINVAL;
	410	}
	411
	412	pgmap = dev_dax->pgmap;
	413	} else {
	414	if (dev_dax->pgmap) {
	415	dev_warn(dev,
	416	"dynamic-dax with pre-populated page map\n");
	417	return -EINVAL;
	418	}
	419
	420	pgmap = devm_kzalloc(dev,
	421	struct_size(pgmap, ranges, dev_dax->nr_range - 1),
	422	GFP_KERNEL);
	423	if (!pgmap)
	424	return -ENOMEM;
	425
	426	pgmap->nr_range = dev_dax->nr_range;
	427	dev_dax->pgmap = pgmap;
	428
	429	for (i = 0; i < dev_dax->nr_range; i++) {
	430	struct range *range = &dev_dax->ranges[i].range;
	431	pgmap->ranges[i] = *range;
	432	}
	433	}
	434
	435	for (i = 0; i < dev_dax->nr_range; i++) {
	436	struct range *range = &dev_dax->ranges[i].range;
	437
	438	if (!devm_request_mem_region(dev, range->start,
	439	range_len(range), dev_name(dev))) {
	440	dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve range\n",
	441	i, range->start, range->end);
	442	return -EBUSY;
	443	}
	444	}
	445
	446	pgmap->type = MEMORY_DEVICE_GENERIC;
	447	if (dev_dax->align > PAGE_SIZE)
	448	pgmap->vmemmap_shift =
	449	order_base_2(dev_dax->align >> PAGE_SHIFT);
	450	addr = devm_memremap_pages(dev, pgmap);
	451	if (IS_ERR(addr))
	452	return PTR_ERR(addr);
	453
	454	inode = dax_inode(dax_dev);
	455	cdev = inode->i_cdev;
	456	cdev_init(cdev, &dax_fops);
	457	cdev->owner = dev->driver->owner;
	458	cdev_set_parent(cdev, &dev->kobj);
	459	rc = cdev_add(cdev, dev->devt, 1);
	460	if (rc)
	461	return rc;
	462
	463	rc = devm_add_action_or_reset(dev, dev_dax_cdev_del, cdev);
	464	if (rc)
	465	return rc;
	466
	467	run_dax(dax_dev);
	468	return devm_add_action_or_reset(dev, dev_dax_kill, dev_dax);
	469	}
	470
	471	static struct dax_device_driver device_dax_driver = {
	472	.probe = dev_dax_probe,
	473	.type = DAXDRV_DEVICE_TYPE,
	474	};
	475
	476	static int __init dax_init(void)
	477	{
	478	return dax_driver_register(&device_dax_driver);
	479	}
	480
	481	static void __exit dax_exit(void)
	482	{
	483	dax_driver_unregister(&device_dax_driver);
	484	}
	485
	486	MODULE_AUTHOR("Intel Corporation");
	487	MODULE_DESCRIPTION("Device DAX: direct access device driver");
	488	MODULE_LICENSE("GPL v2");
	489	module_init(dax_init);
	490	module_exit(dax_exit);
	491	MODULE_ALIAS_DAX_DEVICE(0);