swh:1:snp:77163734605b0ec556b01d897b7bb4a7e30d46b6
Tip revision: b3a9e3b9622ae10064826dccb4f7a52bd88c7407 authored by Linus Torvalds on 14 June 2020, 19:45:04 UTC
Linux 5.8-rc1
Linux 5.8-rc1
Tip revision: b3a9e3b
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 dax_region *dax_region = dev_dax->region;
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 = dax_region->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 ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) == PFN_DEV
&& (vma->vm_flags & VM_DONTCOPY) == 0) {
dev_info_ratelimited(dev,
"%s: %s: fail, dax range requires MADV_DONTFORK\n",
current->comm, func);
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)
{
struct resource *res = &dev_dax->region->res;
phys_addr_t phys;
phys = pgoff * PAGE_SIZE + res->start;
if (phys >= res->start && phys <= res->end) {
if (phys + size - 1 <= res->end)
return phys;
}
return -1;
}
static vm_fault_t __dev_dax_pte_fault(struct dev_dax *dev_dax,
struct vm_fault *vmf, pfn_t *pfn)
{
struct device *dev = &dev_dax->dev;
struct dax_region *dax_region;
phys_addr_t phys;
unsigned int fault_size = PAGE_SIZE;
if (check_vma(dev_dax, vmf->vma, __func__))
return VM_FAULT_SIGBUS;
dax_region = dev_dax->region;
if (dax_region->align > PAGE_SIZE) {
dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
dax_region->align, fault_size);
return VM_FAULT_SIGBUS;
}
if (fault_size != dax_region->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, dax_region->pfn_flags);
return vmf_insert_mixed(vmf->vma, vmf->address, *pfn);
}
static vm_fault_t __dev_dax_pmd_fault(struct dev_dax *dev_dax,
struct vm_fault *vmf, pfn_t *pfn)
{
unsigned long pmd_addr = vmf->address & PMD_MASK;
struct device *dev = &dev_dax->dev;
struct dax_region *dax_region;
phys_addr_t phys;
pgoff_t pgoff;
unsigned int fault_size = PMD_SIZE;
if (check_vma(dev_dax, vmf->vma, __func__))
return VM_FAULT_SIGBUS;
dax_region = dev_dax->region;
if (dax_region->align > PMD_SIZE) {
dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
dax_region->align, fault_size);
return VM_FAULT_SIGBUS;
}
/* dax pmd mappings require pfn_t_devmap() */
if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
dev_dbg(dev, "region lacks devmap flags\n");
return VM_FAULT_SIGBUS;
}
if (fault_size < dax_region->align)
return VM_FAULT_SIGBUS;
else if (fault_size > dax_region->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, dax_region->pfn_flags);
return vmf_insert_pfn_pmd(vmf, *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, pfn_t *pfn)
{
unsigned long pud_addr = vmf->address & PUD_MASK;
struct device *dev = &dev_dax->dev;
struct dax_region *dax_region;
phys_addr_t phys;
pgoff_t pgoff;
unsigned int fault_size = PUD_SIZE;
if (check_vma(dev_dax, vmf->vma, __func__))
return VM_FAULT_SIGBUS;
dax_region = dev_dax->region;
if (dax_region->align > PUD_SIZE) {
dev_dbg(dev, "alignment (%#x) > fault size (%#x)\n",
dax_region->align, fault_size);
return VM_FAULT_SIGBUS;
}
/* dax pud mappings require pfn_t_devmap() */
if ((dax_region->pfn_flags & (PFN_DEV|PFN_MAP)) != (PFN_DEV|PFN_MAP)) {
dev_dbg(dev, "region lacks devmap flags\n");
return VM_FAULT_SIGBUS;
}
if (fault_size < dax_region->align)
return VM_FAULT_SIGBUS;
else if (fault_size > dax_region->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, dax_region->pfn_flags);
return vmf_insert_pfn_pud(vmf, *pfn, vmf->flags & FAULT_FLAG_WRITE);
}
#else
static vm_fault_t __dev_dax_pud_fault(struct dev_dax *dev_dax,
struct vm_fault *vmf, pfn_t *pfn)
{
return VM_FAULT_FALLBACK;
}
#endif /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
enum page_entry_size pe_size)
{
struct file *filp = vmf->vma->vm_file;
unsigned long fault_size;
vm_fault_t rc = VM_FAULT_SIGBUS;
int id;
pfn_t pfn;
struct dev_dax *dev_dax = filp->private_data;
dev_dbg(&dev_dax->dev, "%s: %s (%#lx - %#lx) size = %d\n", current->comm,
(vmf->flags & FAULT_FLAG_WRITE) ? "write" : "read",
vmf->vma->vm_start, vmf->vma->vm_end, pe_size);
id = dax_read_lock();
switch (pe_size) {
case PE_SIZE_PTE:
fault_size = PAGE_SIZE;
rc = __dev_dax_pte_fault(dev_dax, vmf, &pfn);
break;
case PE_SIZE_PMD:
fault_size = PMD_SIZE;
rc = __dev_dax_pmd_fault(dev_dax, vmf, &pfn);
break;
case PE_SIZE_PUD:
fault_size = PUD_SIZE;
rc = __dev_dax_pud_fault(dev_dax, vmf, &pfn);
break;
default:
rc = VM_FAULT_SIGBUS;
}
if (rc == VM_FAULT_NOPAGE) {
unsigned long i;
pgoff_t pgoff;
/*
* In the device-dax case the only possibility for a
* VM_FAULT_NOPAGE result is when device-dax capacity is
* mapped. No need to consider the zero page, or racing
* conflicting mappings.
*/
pgoff = linear_page_index(vmf->vma, vmf->address
& ~(fault_size - 1));
for (i = 0; i < fault_size / PAGE_SIZE; i++) {
struct page *page;
page = pfn_to_page(pfn_t_to_pfn(pfn) + i);
if (page->mapping)
continue;
page->mapping = filp->f_mapping;
page->index = pgoff + i;
}
}
dax_read_unlock(id);
return rc;
}
static vm_fault_t dev_dax_fault(struct vm_fault *vmf)
{
return dev_dax_huge_fault(vmf, PE_SIZE_PTE);
}
static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr)
{
struct file *filp = vma->vm_file;
struct dev_dax *dev_dax = filp->private_data;
struct dax_region *dax_region = dev_dax->region;
if (!IS_ALIGNED(addr, dax_region->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;
struct dax_region *dax_region = dev_dax->region;
return dax_region->align;
}
static const struct vm_operations_struct dax_vm_ops = {
.fault = dev_dax_fault,
.huge_fault = dev_dax_huge_fault,
.split = dev_dax_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;
vma->vm_flags |= 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;
struct dax_region *dax_region;
if (!dev_dax || addr)
goto out;
dax_region = dev_dax->region;
align = dax_region->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 = current->mm->get_unmapped_area(filp, addr, len_align,
pgoff, flags);
if (!IS_ERR_VALUE(addr_align)) {
addr_align += (off - addr_align) & (align - 1);
return addr_align;
}
out:
return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
}
static const struct address_space_operations dev_dax_aops = {
.set_page_dirty = noop_set_page_dirty,
.invalidatepage = noop_invalidatepage,
};
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,
.mmap_supported_flags = MAP_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);
}
int dev_dax_probe(struct device *dev)
{
struct dev_dax *dev_dax = to_dev_dax(dev);
struct dax_device *dax_dev = dev_dax->dax_dev;
struct resource *res = &dev_dax->region->res;
struct inode *inode;
struct cdev *cdev;
void *addr;
int rc;
/* 1:1 map region resource range to device-dax instance range */
if (!devm_request_mem_region(dev, res->start, resource_size(res),
dev_name(dev))) {
dev_warn(dev, "could not reserve region %pR\n", res);
return -EBUSY;
}
dev_dax->pgmap.type = MEMORY_DEVICE_DEVDAX;
addr = devm_memremap_pages(dev, &dev_dax->pgmap);
if (IS_ERR(addr))
return PTR_ERR(addr);
inode = dax_inode(dax_dev);
cdev = inode->i_cdev;
cdev_init(cdev, &dax_fops);
if (dev->class) {
/* for the CONFIG_DEV_DAX_PMEM_COMPAT case */
cdev->owner = dev->parent->driver->owner;
} else
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);
}
EXPORT_SYMBOL_GPL(dev_dax_probe);
static int dev_dax_remove(struct device *dev)
{
/* all probe actions are unwound by devm */
return 0;
}
static struct dax_device_driver device_dax_driver = {
.drv = {
.probe = dev_dax_probe,
.remove = dev_dax_remove,
},
.match_always = 1,
};
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_LICENSE("GPL v2");
module_init(dax_init);
module_exit(dax_exit);
MODULE_ALIAS_DAX_DEVICE(0);