pmem.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Persistent Memory Driver
*
* Copyright (c) 2014-2015, Intel Corporation.
* Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
* Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
*/
#include <linux/blkdev.h>
#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/set_memory.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/badblocks.h>
#include <linux/memremap.h>
#include <linux/vmalloc.h>
#include <linux/blk-mq.h>
#include <linux/pfn_t.h>
#include <linux/slab.h>
#include <linux/uio.h>
#include <linux/dax.h>
#include <linux/nd.h>
#include <linux/backing-dev.h>
#include <linux/mm.h>
#include <asm/cacheflush.h>
#include "pmem.h"
#include "pfn.h"
#include "nd.h"
static struct device *to_dev(struct pmem_device *pmem)
{
/*
* nvdimm bus services need a 'dev' parameter, and we record the device
* at init in bb.dev.
*/
return pmem->bb.dev;
}
static struct nd_region *to_region(struct pmem_device *pmem)
{
return to_nd_region(to_dev(pmem)->parent);
}
static void hwpoison_clear(struct pmem_device *pmem,
phys_addr_t phys, unsigned int len)
{
unsigned long pfn_start, pfn_end, pfn;
/* only pmem in the linear map supports HWPoison */
if (is_vmalloc_addr(pmem->virt_addr))
return;
pfn_start = PHYS_PFN(phys);
pfn_end = pfn_start + PHYS_PFN(len);
for (pfn = pfn_start; pfn < pfn_end; pfn++) {
struct page *page = pfn_to_page(pfn);
/*
* Note, no need to hold a get_dev_pagemap() reference
* here since we're in the driver I/O path and
* outstanding I/O requests pin the dev_pagemap.
*/
if (test_and_clear_pmem_poison(page))
clear_mce_nospec(pfn);
}
}
static blk_status_t pmem_clear_poison(struct pmem_device *pmem,
phys_addr_t offset, unsigned int len)
{
struct device *dev = to_dev(pmem);
sector_t sector;
long cleared;
blk_status_t rc = BLK_STS_OK;
sector = (offset - pmem->data_offset) / 512;
cleared = nvdimm_clear_poison(dev, pmem->phys_addr + offset, len);
if (cleared < len)
rc = BLK_STS_IOERR;
if (cleared > 0 && cleared / 512) {
hwpoison_clear(pmem, pmem->phys_addr + offset, cleared);
cleared /= 512;
dev_dbg(dev, "%#llx clear %ld sector%s\n",
(unsigned long long) sector, cleared,
cleared > 1 ? "s" : "");
badblocks_clear(&pmem->bb, sector, cleared);
if (pmem->bb_state)
sysfs_notify_dirent(pmem->bb_state);
}
arch_invalidate_pmem(pmem->virt_addr + offset, len);
return rc;
}
static void write_pmem(void *pmem_addr, struct page *page,
unsigned int off, unsigned int len)
{
unsigned int chunk;
void *mem;
while (len) {
mem = kmap_atomic(page);
chunk = min_t(unsigned int, len, PAGE_SIZE - off);
memcpy_flushcache(pmem_addr, mem + off, chunk);
kunmap_atomic(mem);
len -= chunk;
off = 0;
page++;
pmem_addr += chunk;
}
}
static blk_status_t read_pmem(struct page *page, unsigned int off,
void *pmem_addr, unsigned int len)
{
unsigned int chunk;
unsigned long rem;
void *mem;
while (len) {
mem = kmap_atomic(page);
chunk = min_t(unsigned int, len, PAGE_SIZE - off);
rem = copy_mc_to_kernel(mem + off, pmem_addr, chunk);
kunmap_atomic(mem);
if (rem)
return BLK_STS_IOERR;
len -= chunk;
off = 0;
page++;
pmem_addr += chunk;
}
return BLK_STS_OK;
}
static blk_status_t pmem_do_read(struct pmem_device *pmem,
struct page *page, unsigned int page_off,
sector_t sector, unsigned int len)
{
blk_status_t rc;
phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
void *pmem_addr = pmem->virt_addr + pmem_off;
if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
return BLK_STS_IOERR;
rc = read_pmem(page, page_off, pmem_addr, len);
flush_dcache_page(page);
return rc;
}
static blk_status_t pmem_do_write(struct pmem_device *pmem,
struct page *page, unsigned int page_off,
sector_t sector, unsigned int len)
{
blk_status_t rc = BLK_STS_OK;
bool bad_pmem = false;
phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
void *pmem_addr = pmem->virt_addr + pmem_off;
if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
bad_pmem = true;
/*
* Note that we write the data both before and after
* clearing poison. The write before clear poison
* handles situations where the latest written data is
* preserved and the clear poison operation simply marks
* the address range as valid without changing the data.
* In this case application software can assume that an
* interrupted write will either return the new good
* data or an error.
*
* However, if pmem_clear_poison() leaves the data in an
* indeterminate state we need to perform the write
* after clear poison.
*/
flush_dcache_page(page);
write_pmem(pmem_addr, page, page_off, len);
if (unlikely(bad_pmem)) {
rc = pmem_clear_poison(pmem, pmem_off, len);
write_pmem(pmem_addr, page, page_off, len);
}
return rc;
}
static blk_qc_t pmem_submit_bio(struct bio *bio)
{
int ret = 0;
blk_status_t rc = 0;
bool do_acct;
unsigned long start;
struct bio_vec bvec;
struct bvec_iter iter;
struct pmem_device *pmem = bio->bi_disk->private_data;
struct nd_region *nd_region = to_region(pmem);
if (bio->bi_opf & REQ_PREFLUSH)
ret = nvdimm_flush(nd_region, bio);
do_acct = blk_queue_io_stat(bio->bi_disk->queue);
if (do_acct)
start = bio_start_io_acct(bio);
bio_for_each_segment(bvec, bio, iter) {
if (op_is_write(bio_op(bio)))
rc = pmem_do_write(pmem, bvec.bv_page, bvec.bv_offset,
iter.bi_sector, bvec.bv_len);
else
rc = pmem_do_read(pmem, bvec.bv_page, bvec.bv_offset,
iter.bi_sector, bvec.bv_len);
if (rc) {
bio->bi_status = rc;
break;
}
}
if (do_acct)
bio_end_io_acct(bio, start);
if (bio->bi_opf & REQ_FUA)
ret = nvdimm_flush(nd_region, bio);
if (ret)
bio->bi_status = errno_to_blk_status(ret);
bio_endio(bio);
return BLK_QC_T_NONE;
}
static int pmem_rw_page(struct block_device *bdev, sector_t sector,
struct page *page, unsigned int op)
{
struct pmem_device *pmem = bdev->bd_disk->private_data;
blk_status_t rc;
if (op_is_write(op))
rc = pmem_do_write(pmem, page, 0, sector, thp_size(page));
else
rc = pmem_do_read(pmem, page, 0, sector, thp_size(page));
/*
* The ->rw_page interface is subtle and tricky. The core
* retries on any error, so we can only invoke page_endio() in
* the successful completion case. Otherwise, we'll see crashes
* caused by double completion.
*/
if (rc == 0)
page_endio(page, op_is_write(op), 0);
return blk_status_to_errno(rc);
}
/* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
__weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
resource_size_t offset = PFN_PHYS(pgoff) + pmem->data_offset;
if (unlikely(is_bad_pmem(&pmem->bb, PFN_PHYS(pgoff) / 512,
PFN_PHYS(nr_pages))))
return -EIO;
if (kaddr)
*kaddr = pmem->virt_addr + offset;
if (pfn)
*pfn = phys_to_pfn_t(pmem->phys_addr + offset, pmem->pfn_flags);
/*
* If badblocks are present, limit known good range to the
* requested range.
*/
if (unlikely(pmem->bb.count))
return nr_pages;
return PHYS_PFN(pmem->size - pmem->pfn_pad - offset);
}
static const struct block_device_operations pmem_fops = {
.owner = THIS_MODULE,
.submit_bio = pmem_submit_bio,
.rw_page = pmem_rw_page,
};
static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
size_t nr_pages)
{
struct pmem_device *pmem = dax_get_private(dax_dev);
return blk_status_to_errno(pmem_do_write(pmem, ZERO_PAGE(0), 0,
PFN_PHYS(pgoff) >> SECTOR_SHIFT,
PAGE_SIZE));
}
static long pmem_dax_direct_access(struct dax_device *dax_dev,
pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn)
{
struct pmem_device *pmem = dax_get_private(dax_dev);
return __pmem_direct_access(pmem, pgoff, nr_pages, kaddr, pfn);
}
/*
* Use the 'no check' versions of copy_from_iter_flushcache() and
* copy_mc_to_iter() to bypass HARDENED_USERCOPY overhead. Bounds
* checking, both file offset and device offset, is handled by
* dax_iomap_actor()
*/
static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i)
{
return _copy_from_iter_flushcache(addr, bytes, i);
}
static size_t pmem_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i)
{
return _copy_mc_to_iter(addr, bytes, i);
}
static const struct dax_operations pmem_dax_ops = {
.direct_access = pmem_dax_direct_access,
.dax_supported = generic_fsdax_supported,
.copy_from_iter = pmem_copy_from_iter,
.copy_to_iter = pmem_copy_to_iter,
.zero_page_range = pmem_dax_zero_page_range,
};
static const struct attribute_group *pmem_attribute_groups[] = {
&dax_attribute_group,
NULL,
};
static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap)
{
struct request_queue *q =
container_of(pgmap->ref, struct request_queue, q_usage_counter);
blk_cleanup_queue(q);
}
static void pmem_release_queue(void *pgmap)
{
pmem_pagemap_cleanup(pgmap);
}
static void pmem_pagemap_kill(struct dev_pagemap *pgmap)
{
struct request_queue *q =
container_of(pgmap->ref, struct request_queue, q_usage_counter);
blk_freeze_queue_start(q);
}
static void pmem_release_disk(void *__pmem)
{
struct pmem_device *pmem = __pmem;
kill_dax(pmem->dax_dev);
put_dax(pmem->dax_dev);
del_gendisk(pmem->disk);
put_disk(pmem->disk);
}
static const struct dev_pagemap_ops fsdax_pagemap_ops = {
.kill = pmem_pagemap_kill,
.cleanup = pmem_pagemap_cleanup,
};
static int pmem_attach_disk(struct device *dev,
struct nd_namespace_common *ndns)
{
struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
struct nd_region *nd_region = to_nd_region(dev->parent);
int nid = dev_to_node(dev), fua;
struct resource *res = &nsio->res;
struct range bb_range;
struct nd_pfn *nd_pfn = NULL;
struct dax_device *dax_dev;
struct nd_pfn_sb *pfn_sb;
struct pmem_device *pmem;
struct request_queue *q;
struct device *gendev;
struct gendisk *disk;
void *addr;
int rc;
unsigned long flags = 0UL;
pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
if (!pmem)
return -ENOMEM;
rc = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
if (rc)
return rc;
/* while nsio_rw_bytes is active, parse a pfn info block if present */
if (is_nd_pfn(dev)) {
nd_pfn = to_nd_pfn(dev);
rc = nvdimm_setup_pfn(nd_pfn, &pmem->pgmap);
if (rc)
return rc;
}
/* we're attaching a block device, disable raw namespace access */
devm_namespace_disable(dev, ndns);
dev_set_drvdata(dev, pmem);
pmem->phys_addr = res->start;
pmem->size = resource_size(res);
fua = nvdimm_has_flush(nd_region);
if (!IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) || fua < 0) {
dev_warn(dev, "unable to guarantee persistence of writes\n");
fua = 0;
}
if (!devm_request_mem_region(dev, res->start, resource_size(res),
dev_name(&ndns->dev))) {
dev_warn(dev, "could not reserve region %pR\n", res);
return -EBUSY;
}
q = blk_alloc_queue(dev_to_node(dev));
if (!q)
return -ENOMEM;
pmem->pfn_flags = PFN_DEV;
pmem->pgmap.ref = &q->q_usage_counter;
if (is_nd_pfn(dev)) {
pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
pmem->pgmap.ops = &fsdax_pagemap_ops;
addr = devm_memremap_pages(dev, &pmem->pgmap);
pfn_sb = nd_pfn->pfn_sb;
pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
pmem->pfn_pad = resource_size(res) -
range_len(&pmem->pgmap.range);
pmem->pfn_flags |= PFN_MAP;
bb_range = pmem->pgmap.range;
bb_range.start += pmem->data_offset;
} else if (pmem_should_map_pages(dev)) {
pmem->pgmap.range.start = res->start;
pmem->pgmap.range.end = res->end;
pmem->pgmap.nr_range = 1;
pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
pmem->pgmap.ops = &fsdax_pagemap_ops;
addr = devm_memremap_pages(dev, &pmem->pgmap);
pmem->pfn_flags |= PFN_MAP;
bb_range = pmem->pgmap.range;
} else {
if (devm_add_action_or_reset(dev, pmem_release_queue,
&pmem->pgmap))
return -ENOMEM;
addr = devm_memremap(dev, pmem->phys_addr,
pmem->size, ARCH_MEMREMAP_PMEM);
bb_range.start = res->start;
bb_range.end = res->end;
}
if (IS_ERR(addr))
return PTR_ERR(addr);
pmem->virt_addr = addr;
blk_queue_write_cache(q, true, fua);
blk_queue_physical_block_size(q, PAGE_SIZE);
blk_queue_logical_block_size(q, pmem_sector_size(ndns));
blk_queue_max_hw_sectors(q, UINT_MAX);
blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
if (pmem->pfn_flags & PFN_MAP)
blk_queue_flag_set(QUEUE_FLAG_DAX, q);
disk = alloc_disk_node(0, nid);
if (!disk)
return -ENOMEM;
pmem->disk = disk;
disk->fops = &pmem_fops;
disk->queue = q;
disk->flags = GENHD_FL_EXT_DEVT;
disk->private_data = pmem;
nvdimm_namespace_disk_name(ndns, disk->disk_name);
set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)
/ 512);
if (devm_init_badblocks(dev, &pmem->bb))
return -ENOMEM;
nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_range);
disk->bb = &pmem->bb;
if (is_nvdimm_sync(nd_region))
flags = DAXDEV_F_SYNC;
dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops, flags);
if (IS_ERR(dax_dev)) {
put_disk(disk);
return PTR_ERR(dax_dev);
}
dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
pmem->dax_dev = dax_dev;
gendev = disk_to_dev(disk);
gendev->groups = pmem_attribute_groups;
device_add_disk(dev, disk, NULL);
if (devm_add_action_or_reset(dev, pmem_release_disk, pmem))
return -ENOMEM;
nvdimm_check_and_set_ro(disk);
pmem->bb_state = sysfs_get_dirent(disk_to_dev(disk)->kobj.sd,
"badblocks");
if (!pmem->bb_state)
dev_warn(dev, "'badblocks' notification disabled\n");
return 0;
}
static int nd_pmem_probe(struct device *dev)
{
int ret;
struct nd_namespace_common *ndns;
ndns = nvdimm_namespace_common_probe(dev);
if (IS_ERR(ndns))
return PTR_ERR(ndns);
if (is_nd_btt(dev))
return nvdimm_namespace_attach_btt(ndns);
if (is_nd_pfn(dev))
return pmem_attach_disk(dev, ndns);
ret = devm_namespace_enable(dev, ndns, nd_info_block_reserve());
if (ret)
return ret;
ret = nd_btt_probe(dev, ndns);
if (ret == 0)
return -ENXIO;
/*
* We have two failure conditions here, there is no
* info reserver block or we found a valid info reserve block
* but failed to initialize the pfn superblock.
*
* For the first case consider namespace as a raw pmem namespace
* and attach a disk.
*
* For the latter, consider this a success and advance the namespace
* seed.
*/
ret = nd_pfn_probe(dev, ndns);
if (ret == 0)
return -ENXIO;
else if (ret == -EOPNOTSUPP)
return ret;
ret = nd_dax_probe(dev, ndns);
if (ret == 0)
return -ENXIO;
else if (ret == -EOPNOTSUPP)
return ret;
/* probe complete, attach handles namespace enabling */
devm_namespace_disable(dev, ndns);
return pmem_attach_disk(dev, ndns);
}
static int nd_pmem_remove(struct device *dev)
{
struct pmem_device *pmem = dev_get_drvdata(dev);
if (is_nd_btt(dev))
nvdimm_namespace_detach_btt(to_nd_btt(dev));
else {
/*
* Note, this assumes nd_device_lock() context to not
* race nd_pmem_notify()
*/
sysfs_put(pmem->bb_state);
pmem->bb_state = NULL;
}
nvdimm_flush(to_nd_region(dev->parent), NULL);
return 0;
}
static void nd_pmem_shutdown(struct device *dev)
{
nvdimm_flush(to_nd_region(dev->parent), NULL);
}
static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
{
struct nd_region *nd_region;
resource_size_t offset = 0, end_trunc = 0;
struct nd_namespace_common *ndns;
struct nd_namespace_io *nsio;
struct badblocks *bb;
struct range range;
struct kernfs_node *bb_state;
if (event != NVDIMM_REVALIDATE_POISON)
return;
if (is_nd_btt(dev)) {
struct nd_btt *nd_btt = to_nd_btt(dev);
ndns = nd_btt->ndns;
nd_region = to_nd_region(ndns->dev.parent);
nsio = to_nd_namespace_io(&ndns->dev);
bb = &nsio->bb;
bb_state = NULL;
} else {
struct pmem_device *pmem = dev_get_drvdata(dev);
nd_region = to_region(pmem);
bb = &pmem->bb;
bb_state = pmem->bb_state;
if (is_nd_pfn(dev)) {
struct nd_pfn *nd_pfn = to_nd_pfn(dev);
struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
ndns = nd_pfn->ndns;
offset = pmem->data_offset +
__le32_to_cpu(pfn_sb->start_pad);
end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
} else {
ndns = to_ndns(dev);
}
nsio = to_nd_namespace_io(&ndns->dev);
}
range.start = nsio->res.start + offset;
range.end = nsio->res.end - end_trunc;
nvdimm_badblocks_populate(nd_region, bb, &range);
if (bb_state)
sysfs_notify_dirent(bb_state);
}
MODULE_ALIAS("pmem");
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
static struct nd_device_driver nd_pmem_driver = {
.probe = nd_pmem_probe,
.remove = nd_pmem_remove,
.notify = nd_pmem_notify,
.shutdown = nd_pmem_shutdown,
.drv = {
.name = "nd_pmem",
},
.type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
};
module_nd_driver(nd_pmem_driver);
MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
MODULE_LICENSE("GPL v2");