pfn_devs.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright(c) 2013-2016 Intel Corporation. All rights reserved.
  4 */
  5#include <linux/memremap.h>
  6#include <linux/blkdev.h>
  7#include <linux/device.h>
  8#include <linux/sizes.h>
  9#include <linux/slab.h>
 10#include <linux/fs.h>
 11#include <linux/mm.h>
 12#include "nd-core.h"
 13#include "pfn.h"
 14#include "nd.h"
 15
 16static const bool page_struct_override = IS_ENABLED(CONFIG_NVDIMM_KMSAN);
 17
 18static void nd_pfn_release(struct device *dev)
 19{
 20	struct nd_region *nd_region = to_nd_region(dev->parent);
 21	struct nd_pfn *nd_pfn = to_nd_pfn(dev);
 22
 23	dev_dbg(dev, "trace\n");
 24	nd_detach_ndns(&nd_pfn->dev, &nd_pfn->ndns);
 25	ida_free(&nd_region->pfn_ida, nd_pfn->id);
 26	kfree(nd_pfn->uuid);
 27	kfree(nd_pfn);
 28}
 29
 30struct nd_pfn *to_nd_pfn(struct device *dev)
 31{
 32	struct nd_pfn *nd_pfn = container_of(dev, struct nd_pfn, dev);
 33
 34	WARN_ON(!is_nd_pfn(dev));
 35	return nd_pfn;
 36}
 37EXPORT_SYMBOL(to_nd_pfn);
 38
 39static ssize_t mode_show(struct device *dev,
 40		struct device_attribute *attr, char *buf)
 41{
 42	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 43
 44	switch (nd_pfn->mode) {
 45	case PFN_MODE_RAM:
 46		return sprintf(buf, "ram\n");
 47	case PFN_MODE_PMEM:
 48		return sprintf(buf, "pmem\n");
 49	default:
 50		return sprintf(buf, "none\n");
 51	}
 52}
 53
 54static ssize_t mode_store(struct device *dev,
 55		struct device_attribute *attr, const char *buf, size_t len)
 56{
 57	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 58	ssize_t rc = 0;
 59	size_t n = len - 1;
 60
 61	guard(device)(dev);
 62	guard(nvdimm_bus)(dev);
 63	if (dev->driver)
 64		return -EBUSY;
 65
 66	if (strncmp(buf, "pmem\n", n) == 0
 67			|| strncmp(buf, "pmem", n) == 0) {
 68		nd_pfn->mode = PFN_MODE_PMEM;
 69	} else if (strncmp(buf, "ram\n", n) == 0
 70			|| strncmp(buf, "ram", n) == 0)
 71		nd_pfn->mode = PFN_MODE_RAM;
 72	else if (strncmp(buf, "none\n", n) == 0
 73			|| strncmp(buf, "none", n) == 0)
 74		nd_pfn->mode = PFN_MODE_NONE;
 75	else
 76		rc = -EINVAL;
 77	dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
 78			buf[len - 1] == '\n' ? "" : "\n");
 79
 80	return rc ? rc : len;
 81}
 82static DEVICE_ATTR_RW(mode);
 83
 84static ssize_t align_show(struct device *dev,
 85		struct device_attribute *attr, char *buf)
 86{
 87	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
 88
 89	return sprintf(buf, "%ld\n", nd_pfn->align);
 90}
 91
 92static unsigned long *nd_pfn_supported_alignments(unsigned long *alignments)
 93{
 94
 95	alignments[0] = PAGE_SIZE;
 96
 97	if (has_transparent_hugepage()) {
 98		alignments[1] = HPAGE_PMD_SIZE;
 99		if (has_transparent_pud_hugepage())
100			alignments[2] = HPAGE_PUD_SIZE;
101	}
102
103	return alignments;
104}
105
106/*
107 * Use pmd mapping if supported as default alignment
108 */
109static unsigned long nd_pfn_default_alignment(void)
110{
111
112	if (has_transparent_hugepage())
113		return HPAGE_PMD_SIZE;
114	return PAGE_SIZE;
115}
116
117static ssize_t align_store(struct device *dev,
118		struct device_attribute *attr, const char *buf, size_t len)
119{
120	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
121	unsigned long aligns[MAX_NVDIMM_ALIGN] = { [0] = 0, };
122	ssize_t rc;
123
124	guard(device)(dev);
125	guard(nvdimm_bus)(dev);
126	rc = nd_size_select_store(dev, buf, &nd_pfn->align,
127			nd_pfn_supported_alignments(aligns));
128	dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
129			buf[len - 1] == '\n' ? "" : "\n");
130
131	return rc ? rc : len;
132}
133static DEVICE_ATTR_RW(align);
134
135static ssize_t uuid_show(struct device *dev,
136		struct device_attribute *attr, char *buf)
137{
138	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
139
140	if (nd_pfn->uuid)
141		return sprintf(buf, "%pUb\n", nd_pfn->uuid);
142	return sprintf(buf, "\n");
143}
144
145static ssize_t uuid_store(struct device *dev,
146		struct device_attribute *attr, const char *buf, size_t len)
147{
148	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
149	ssize_t rc;
150
151	device_lock(dev);
152	rc = nd_uuid_store(dev, &nd_pfn->uuid, buf, len);
153	dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
154			buf[len - 1] == '\n' ? "" : "\n");
155	device_unlock(dev);
156
157	return rc ? rc : len;
158}
159static DEVICE_ATTR_RW(uuid);
160
161static ssize_t namespace_show(struct device *dev,
162		struct device_attribute *attr, char *buf)
163{
164	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
165
166	guard(nvdimm_bus)(dev);
167	return sprintf(buf, "%s\n", nd_pfn->ndns
168			? dev_name(&nd_pfn->ndns->dev) : "");
169}
170
171static ssize_t namespace_store(struct device *dev,
172		struct device_attribute *attr, const char *buf, size_t len)
173{
174	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
175	ssize_t rc;
176
177	guard(device)(dev);
178	guard(nvdimm_bus)(dev);
179	rc = nd_namespace_store(dev, &nd_pfn->ndns, buf, len);
180	dev_dbg(dev, "result: %zd wrote: %s%s", rc, buf,
181			buf[len - 1] == '\n' ? "" : "\n");
182
183	return rc;
184}
185static DEVICE_ATTR_RW(namespace);
186
187static ssize_t resource_show(struct device *dev,
188		struct device_attribute *attr, char *buf)
189{
190	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
191	ssize_t rc;
192
193	device_lock(dev);
194	if (dev->driver) {
195		struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
196		u64 offset = __le64_to_cpu(pfn_sb->dataoff);
197		struct nd_namespace_common *ndns = nd_pfn->ndns;
198		u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
199		struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
200
201		rc = sprintf(buf, "%#llx\n", (unsigned long long) nsio->res.start
202				+ start_pad + offset);
203	} else {
204		/* no address to convey if the pfn instance is disabled */
205		rc = -ENXIO;
206	}
207	device_unlock(dev);
208
209	return rc;
210}
211static DEVICE_ATTR_ADMIN_RO(resource);
212
213static ssize_t size_show(struct device *dev,
214		struct device_attribute *attr, char *buf)
215{
216	struct nd_pfn *nd_pfn = to_nd_pfn_safe(dev);
217	ssize_t rc;
218
219	device_lock(dev);
220	if (dev->driver) {
221		struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
222		u64 offset = __le64_to_cpu(pfn_sb->dataoff);
223		struct nd_namespace_common *ndns = nd_pfn->ndns;
224		u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
225		u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
226		struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
227
228		rc = sprintf(buf, "%llu\n", (unsigned long long)
229				resource_size(&nsio->res) - start_pad
230				- end_trunc - offset);
231	} else {
232		/* no size to convey if the pfn instance is disabled */
233		rc = -ENXIO;
234	}
235	device_unlock(dev);
236
237	return rc;
238}
239static DEVICE_ATTR_RO(size);
240
241static ssize_t supported_alignments_show(struct device *dev,
242		struct device_attribute *attr, char *buf)
243{
244	unsigned long aligns[MAX_NVDIMM_ALIGN] = { [0] = 0, };
245
246	return nd_size_select_show(0,
247			nd_pfn_supported_alignments(aligns), buf);
248}
249static DEVICE_ATTR_RO(supported_alignments);
250
251static struct attribute *nd_pfn_attributes[] = {
252	&dev_attr_mode.attr,
253	&dev_attr_namespace.attr,
254	&dev_attr_uuid.attr,
255	&dev_attr_align.attr,
256	&dev_attr_resource.attr,
257	&dev_attr_size.attr,
258	&dev_attr_supported_alignments.attr,
259	NULL,
260};
261
262static struct attribute_group nd_pfn_attribute_group = {
263	.attrs = nd_pfn_attributes,
264};
265
266const struct attribute_group *nd_pfn_attribute_groups[] = {
267	&nd_pfn_attribute_group,
268	&nd_device_attribute_group,
269	&nd_numa_attribute_group,
270	NULL,
271};
272
273static const struct device_type nd_pfn_device_type = {
274	.name = "nd_pfn",
275	.release = nd_pfn_release,
276	.groups = nd_pfn_attribute_groups,
277};
278
279bool is_nd_pfn(struct device *dev)
280{
281	return dev ? dev->type == &nd_pfn_device_type : false;
282}
283EXPORT_SYMBOL(is_nd_pfn);
284
285static struct lock_class_key nvdimm_pfn_key;
286
287struct device *nd_pfn_devinit(struct nd_pfn *nd_pfn,
288		struct nd_namespace_common *ndns)
289{
290	struct device *dev;
291
292	if (!nd_pfn)
293		return NULL;
294
295	nd_pfn->mode = PFN_MODE_NONE;
296	nd_pfn->align = nd_pfn_default_alignment();
297	dev = &nd_pfn->dev;
298	device_initialize(&nd_pfn->dev);
299	lockdep_set_class(&nd_pfn->dev.mutex, &nvdimm_pfn_key);
300	if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) {
301		dev_dbg(&ndns->dev, "failed, already claimed by %s\n",
302				dev_name(ndns->claim));
303		put_device(dev);
304		return NULL;
305	}
306	return dev;
307}
308
309static struct nd_pfn *nd_pfn_alloc(struct nd_region *nd_region)
310{
311	struct nd_pfn *nd_pfn;
312	struct device *dev;
313
314	nd_pfn = kzalloc(sizeof(*nd_pfn), GFP_KERNEL);
315	if (!nd_pfn)
316		return NULL;
317
318	nd_pfn->id = ida_alloc(&nd_region->pfn_ida, GFP_KERNEL);
319	if (nd_pfn->id < 0) {
320		kfree(nd_pfn);
321		return NULL;
322	}
323
324	dev = &nd_pfn->dev;
325	dev_set_name(dev, "pfn%d.%d", nd_region->id, nd_pfn->id);
326	dev->type = &nd_pfn_device_type;
327	dev->parent = &nd_region->dev;
328
329	return nd_pfn;
330}
331
332struct device *nd_pfn_create(struct nd_region *nd_region)
333{
334	struct nd_pfn *nd_pfn;
335	struct device *dev;
336
337	if (!is_memory(&nd_region->dev))
338		return NULL;
339
340	nd_pfn = nd_pfn_alloc(nd_region);
341	dev = nd_pfn_devinit(nd_pfn, NULL);
342
343	nd_device_register(dev);
344	return dev;
345}
346
347/*
348 * nd_pfn_clear_memmap_errors() clears any errors in the volatile memmap
349 * space associated with the namespace. If the memmap is set to DRAM, then
350 * this is a no-op. Since the memmap area is freshly initialized during
351 * probe, we have an opportunity to clear any badblocks in this area.
352 */
353static int nd_pfn_clear_memmap_errors(struct nd_pfn *nd_pfn)
354{
355	struct nd_region *nd_region = to_nd_region(nd_pfn->dev.parent);
356	struct nd_namespace_common *ndns = nd_pfn->ndns;
357	void *zero_page = page_address(ZERO_PAGE(0));
358	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
359	int meta_num, rc, bb_present;
360	sector_t first_bad, meta_start;
361	struct nd_namespace_io *nsio;
362	sector_t num_bad;
363
364	if (nd_pfn->mode != PFN_MODE_PMEM)
365		return 0;
366
367	nsio = to_nd_namespace_io(&ndns->dev);
368	meta_start = (SZ_4K + sizeof(*pfn_sb)) >> 9;
369	meta_num = (le64_to_cpu(pfn_sb->dataoff) >> 9) - meta_start;
370
371	/*
372	 * re-enable the namespace with correct size so that we can access
373	 * the device memmap area.
374	 */
375	devm_namespace_disable(&nd_pfn->dev, ndns);
376	rc = devm_namespace_enable(&nd_pfn->dev, ndns, le64_to_cpu(pfn_sb->dataoff));
377	if (rc)
378		return rc;
379
380	do {
381		unsigned long zero_len;
382		u64 nsoff;
383
384		bb_present = badblocks_check(&nd_region->bb, meta_start,
385				meta_num, &first_bad, &num_bad);
386		if (bb_present) {
387			dev_dbg(&nd_pfn->dev, "meta: %llx badblocks at %llx\n",
388					num_bad, first_bad);
389			nsoff = ALIGN_DOWN((nd_region->ndr_start
390					+ (first_bad << 9)) - nsio->res.start,
391					PAGE_SIZE);
392			zero_len = ALIGN(num_bad << 9, PAGE_SIZE);
393			while (zero_len) {
394				unsigned long chunk = min(zero_len, PAGE_SIZE);
395
396				rc = nvdimm_write_bytes(ndns, nsoff, zero_page,
397							chunk, 0);
398				if (rc)
399					break;
400
401				zero_len -= chunk;
402				nsoff += chunk;
403			}
404			if (rc) {
405				dev_err(&nd_pfn->dev,
406					"error clearing %llx badblocks at %llx\n",
407					num_bad, first_bad);
408				return rc;
409			}
410		}
411	} while (bb_present);
412
413	return 0;
414}
415
416static bool nd_supported_alignment(unsigned long align)
417{
418	int i;
419	unsigned long supported[MAX_NVDIMM_ALIGN] = { [0] = 0, };
420
421	if (align == 0)
422		return false;
423
424	nd_pfn_supported_alignments(supported);
425	for (i = 0; supported[i]; i++)
426		if (align == supported[i])
427			return true;
428	return false;
429}
430
431/**
432 * nd_pfn_validate - read and validate info-block
433 * @nd_pfn: fsdax namespace runtime state / properties
434 * @sig: 'devdax' or 'fsdax' signature
435 *
436 * Upon return the info-block buffer contents (->pfn_sb) are
437 * indeterminate when validation fails, and a coherent info-block
438 * otherwise.
439 */
440int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
441{
442	u64 checksum, offset;
443	struct resource *res;
444	enum nd_pfn_mode mode;
445	resource_size_t res_size;
446	struct nd_namespace_io *nsio;
447	unsigned long align, start_pad, end_trunc;
448	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
449	struct nd_namespace_common *ndns = nd_pfn->ndns;
450	const uuid_t *parent_uuid = nd_dev_to_uuid(&ndns->dev);
451
452	if (!pfn_sb || !ndns)
453		return -ENODEV;
454
455	if (!is_memory(nd_pfn->dev.parent))
456		return -ENODEV;
457
458	if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0))
459		return -ENXIO;
460
461	if (memcmp(pfn_sb->signature, sig, PFN_SIG_LEN) != 0)
462		return -ENODEV;
463
464	checksum = le64_to_cpu(pfn_sb->checksum);
465	pfn_sb->checksum = 0;
466	if (checksum != nd_sb_checksum((struct nd_gen_sb *) pfn_sb))
467		return -ENODEV;
468	pfn_sb->checksum = cpu_to_le64(checksum);
469
470	if (memcmp(pfn_sb->parent_uuid, parent_uuid, 16) != 0)
471		return -ENODEV;
472
473	if (__le16_to_cpu(pfn_sb->version_minor) < 1) {
474		pfn_sb->start_pad = 0;
475		pfn_sb->end_trunc = 0;
476	}
477
478	if (__le16_to_cpu(pfn_sb->version_minor) < 2)
479		pfn_sb->align = 0;
480
481	if (__le16_to_cpu(pfn_sb->version_minor) < 4) {
482		pfn_sb->page_struct_size = cpu_to_le16(64);
483		pfn_sb->page_size = cpu_to_le32(PAGE_SIZE);
484	}
485
486	switch (le32_to_cpu(pfn_sb->mode)) {
487	case PFN_MODE_RAM:
488	case PFN_MODE_PMEM:
489		break;
490	default:
491		return -ENXIO;
492	}
493
494	align = le32_to_cpu(pfn_sb->align);
495	offset = le64_to_cpu(pfn_sb->dataoff);
496	start_pad = le32_to_cpu(pfn_sb->start_pad);
497	end_trunc = le32_to_cpu(pfn_sb->end_trunc);
498	if (align == 0)
499		align = 1UL << ilog2(offset);
500	mode = le32_to_cpu(pfn_sb->mode);
501
502	if ((le32_to_cpu(pfn_sb->page_size) > PAGE_SIZE) &&
503			(mode == PFN_MODE_PMEM)) {
504		dev_err(&nd_pfn->dev,
505				"init failed, page size mismatch %d\n",
506				le32_to_cpu(pfn_sb->page_size));
507		return -EOPNOTSUPP;
508	}
509
510	if ((le16_to_cpu(pfn_sb->page_struct_size) < sizeof(struct page)) &&
511			(mode == PFN_MODE_PMEM)) {
512		dev_err(&nd_pfn->dev,
513				"init failed, struct page size mismatch %d\n",
514				le16_to_cpu(pfn_sb->page_struct_size));
515		return -EOPNOTSUPP;
516	}
517
518	/*
519	 * Check whether the we support the alignment. For Dax if the
520	 * superblock alignment is not matching, we won't initialize
521	 * the device.
522	 */
523	if (!nd_supported_alignment(align) &&
524			!memcmp(pfn_sb->signature, DAX_SIG, PFN_SIG_LEN)) {
525		dev_err(&nd_pfn->dev, "init failed, alignment mismatch: "
526				"%ld:%ld\n", nd_pfn->align, align);
527		return -EOPNOTSUPP;
528	}
529
530	if (!nd_pfn->uuid) {
531		/*
532		 * When probing a namespace via nd_pfn_probe() the uuid
533		 * is NULL (see: nd_pfn_devinit()) we init settings from
534		 * pfn_sb
535		 */
536		nd_pfn->uuid = kmemdup(pfn_sb->uuid, 16, GFP_KERNEL);
537		if (!nd_pfn->uuid)
538			return -ENOMEM;
539		nd_pfn->align = align;
540		nd_pfn->mode = mode;
541	} else {
542		/*
543		 * When probing a pfn / dax instance we validate the
544		 * live settings against the pfn_sb
545		 */
546		if (memcmp(nd_pfn->uuid, pfn_sb->uuid, 16) != 0)
547			return -ENODEV;
548
549		/*
550		 * If the uuid validates, but other settings mismatch
551		 * return EINVAL because userspace has managed to change
552		 * the configuration without specifying new
553		 * identification.
554		 */
555		if (nd_pfn->align != align || nd_pfn->mode != mode) {
556			dev_err(&nd_pfn->dev,
557					"init failed, settings mismatch\n");
558			dev_dbg(&nd_pfn->dev, "align: %lx:%lx mode: %d:%d\n",
559					nd_pfn->align, align, nd_pfn->mode,
560					mode);
561			return -EOPNOTSUPP;
562		}
563	}
564
565	if (align > nvdimm_namespace_capacity(ndns)) {
566		dev_err(&nd_pfn->dev, "alignment: %lx exceeds capacity %llx\n",
567				align, nvdimm_namespace_capacity(ndns));
568		return -EOPNOTSUPP;
569	}
570
571	/*
572	 * These warnings are verbose because they can only trigger in
573	 * the case where the physical address alignment of the
574	 * namespace has changed since the pfn superblock was
575	 * established.
576	 */
577	nsio = to_nd_namespace_io(&ndns->dev);
578	res = &nsio->res;
579	res_size = resource_size(res);
580	if (offset >= res_size) {
581		dev_err(&nd_pfn->dev, "pfn array size exceeds capacity of %s\n",
582				dev_name(&ndns->dev));
583		return -EOPNOTSUPP;
584	}
585
586	if ((align && !IS_ALIGNED(res->start + offset + start_pad, align))
587			|| !IS_ALIGNED(offset, PAGE_SIZE)) {
588		dev_err(&nd_pfn->dev,
589				"bad offset: %#llx dax disabled align: %#lx\n",
590				offset, align);
591		return -EOPNOTSUPP;
592	}
593
594	if (!IS_ALIGNED(res->start + start_pad, memremap_compat_align())) {
595		dev_err(&nd_pfn->dev, "resource start misaligned\n");
596		return -EOPNOTSUPP;
597	}
598
599	if (!IS_ALIGNED(res->end + 1 - end_trunc, memremap_compat_align())) {
600		dev_err(&nd_pfn->dev, "resource end misaligned\n");
601		return -EOPNOTSUPP;
602	}
603
604	if (offset >= (res_size - start_pad - end_trunc)) {
605		dev_err(&nd_pfn->dev, "bad offset with small namespace\n");
606		return -EOPNOTSUPP;
607	}
608	return 0;
609}
610EXPORT_SYMBOL(nd_pfn_validate);
611
612int nd_pfn_probe(struct device *dev, struct nd_namespace_common *ndns)
613{
614	int rc;
615	struct nd_pfn *nd_pfn;
616	struct device *pfn_dev;
617	struct nd_pfn_sb *pfn_sb;
618	struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
619
620	if (ndns->force_raw)
621		return -ENODEV;
622
623	switch (ndns->claim_class) {
624	case NVDIMM_CCLASS_NONE:
625	case NVDIMM_CCLASS_PFN:
626		break;
627	default:
628		return -ENODEV;
629	}
630
631	scoped_guard(nvdimm_bus, &ndns->dev) {
632		nd_pfn = nd_pfn_alloc(nd_region);
633		pfn_dev = nd_pfn_devinit(nd_pfn, ndns);
634	}
635	if (!pfn_dev)
636		return -ENOMEM;
637	pfn_sb = devm_kmalloc(dev, sizeof(*pfn_sb), GFP_KERNEL);
638	nd_pfn = to_nd_pfn(pfn_dev);
639	nd_pfn->pfn_sb = pfn_sb;
640	rc = nd_pfn_validate(nd_pfn, PFN_SIG);
641	dev_dbg(dev, "pfn: %s\n", rc == 0 ? dev_name(pfn_dev) : "<none>");
642	if (rc < 0) {
643		nd_detach_ndns(pfn_dev, &nd_pfn->ndns);
644		put_device(pfn_dev);
645	} else
646		nd_device_register(pfn_dev);
647
648	return rc;
649}
650EXPORT_SYMBOL(nd_pfn_probe);
651
652/*
653 * We hotplug memory at sub-section granularity, pad the reserved area
654 * from the previous section base to the namespace base address.
655 */
656static unsigned long init_altmap_base(resource_size_t base)
657{
658	unsigned long base_pfn = PHYS_PFN(base);
659
660	return SUBSECTION_ALIGN_DOWN(base_pfn);
661}
662
663static unsigned long init_altmap_reserve(resource_size_t base)
664{
665	unsigned long reserve = nd_info_block_reserve() >> PAGE_SHIFT;
666	unsigned long base_pfn = PHYS_PFN(base);
667
668	reserve += base_pfn - SUBSECTION_ALIGN_DOWN(base_pfn);
669	return reserve;
670}
671
672static int __nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
673{
674	struct range *range = &pgmap->range;
675	struct vmem_altmap *altmap = &pgmap->altmap;
676	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
677	u64 offset = le64_to_cpu(pfn_sb->dataoff);
678	u32 start_pad = __le32_to_cpu(pfn_sb->start_pad);
679	u32 end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
680	u32 reserve = nd_info_block_reserve();
681	struct nd_namespace_common *ndns = nd_pfn->ndns;
682	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
683	resource_size_t base = nsio->res.start + start_pad;
684	resource_size_t end = nsio->res.end - end_trunc;
685	struct vmem_altmap __altmap = {
686		.base_pfn = init_altmap_base(base),
687		.reserve = init_altmap_reserve(base),
688		.end_pfn = PHYS_PFN(end),
689	};
690
691	*range = (struct range) {
692		.start = nsio->res.start + start_pad,
693		.end = nsio->res.end - end_trunc,
694	};
695	pgmap->nr_range = 1;
696	if (nd_pfn->mode == PFN_MODE_RAM) {
697		if (offset < reserve)
698			return -EINVAL;
699		nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
700	} else if (nd_pfn->mode == PFN_MODE_PMEM) {
701		nd_pfn->npfns = PHYS_PFN((range_len(range) - offset));
702		if (le64_to_cpu(nd_pfn->pfn_sb->npfns) > nd_pfn->npfns)
703			dev_info(&nd_pfn->dev,
704					"number of pfns truncated from %lld to %ld\n",
705					le64_to_cpu(nd_pfn->pfn_sb->npfns),
706					nd_pfn->npfns);
707		memcpy(altmap, &__altmap, sizeof(*altmap));
708		altmap->free = PHYS_PFN(offset - reserve);
709		altmap->alloc = 0;
710		pgmap->flags |= PGMAP_ALTMAP_VALID;
711	} else
712		return -ENXIO;
713
714	return 0;
715}
716
717static int nd_pfn_init(struct nd_pfn *nd_pfn)
718{
719	struct nd_namespace_common *ndns = nd_pfn->ndns;
720	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
721	resource_size_t start, size;
722	struct nd_region *nd_region;
723	unsigned long npfns, align;
724	u32 end_trunc;
725	struct nd_pfn_sb *pfn_sb;
726	phys_addr_t offset;
727	const char *sig;
728	u64 checksum;
729	int rc;
730
731	pfn_sb = devm_kmalloc(&nd_pfn->dev, sizeof(*pfn_sb), GFP_KERNEL);
732	if (!pfn_sb)
733		return -ENOMEM;
734
735	nd_pfn->pfn_sb = pfn_sb;
736	if (is_nd_dax(&nd_pfn->dev))
737		sig = DAX_SIG;
738	else
739		sig = PFN_SIG;
740
741	rc = nd_pfn_validate(nd_pfn, sig);
742	if (rc == 0)
743		return nd_pfn_clear_memmap_errors(nd_pfn);
744	if (rc != -ENODEV)
745		return rc;
746
747	/* no info block, do init */;
748	memset(pfn_sb, 0, sizeof(*pfn_sb));
749
750	nd_region = to_nd_region(nd_pfn->dev.parent);
751	if (nd_region->ro) {
752		dev_info(&nd_pfn->dev,
753				"%s is read-only, unable to init metadata\n",
754				dev_name(&nd_region->dev));
755		return -ENXIO;
756	}
757
758	start = nsio->res.start;
759	size = resource_size(&nsio->res);
760	npfns = PHYS_PFN(size - SZ_8K);
761	align = max(nd_pfn->align, memremap_compat_align());
762
763	/*
764	 * When @start is misaligned fail namespace creation. See
765	 * the 'struct nd_pfn_sb' commentary on why ->start_pad is not
766	 * an option.
767	 */
768	if (!IS_ALIGNED(start, memremap_compat_align())) {
769		dev_err(&nd_pfn->dev, "%s: start %pa misaligned to %#lx\n",
770				dev_name(&ndns->dev), &start,
771				memremap_compat_align());
772		return -EINVAL;
773	}
774	end_trunc = start + size - ALIGN_DOWN(start + size, align);
775	if (nd_pfn->mode == PFN_MODE_PMEM) {
776		unsigned long page_map_size = MAX_STRUCT_PAGE_SIZE * npfns;
777
778		/*
779		 * The altmap should be padded out to the block size used
780		 * when populating the vmemmap. This *should* be equal to
781		 * PMD_SIZE for most architectures.
782		 *
783		 * Also make sure size of struct page is less than
784		 * MAX_STRUCT_PAGE_SIZE. The goal here is compatibility in the
785		 * face of production kernel configurations that reduce the
786		 * 'struct page' size below MAX_STRUCT_PAGE_SIZE. For debug
787		 * kernel configurations that increase the 'struct page' size
788		 * above MAX_STRUCT_PAGE_SIZE, the page_struct_override allows
789		 * for continuing with the capacity that will be wasted when
790		 * reverting to a production kernel configuration. Otherwise,
791		 * those configurations are blocked by default.
792		 */
793		if (sizeof(struct page) > MAX_STRUCT_PAGE_SIZE) {
794			if (page_struct_override)
795				page_map_size = sizeof(struct page) * npfns;
796			else {
797				dev_err(&nd_pfn->dev,
798					"Memory debug options prevent using pmem for the page map\n");
799				return -EINVAL;
800			}
801		}
802		offset = ALIGN(start + SZ_8K + page_map_size, align) - start;
803	} else if (nd_pfn->mode == PFN_MODE_RAM)
804		offset = ALIGN(start + SZ_8K, align) - start;
805	else
806		return -ENXIO;
807
808	if (offset >= (size - end_trunc)) {
809		/* This results in zero size devices */
810		dev_err(&nd_pfn->dev, "%s unable to satisfy requested alignment\n",
811				dev_name(&ndns->dev));
812		return -ENXIO;
813	}
814
815	npfns = PHYS_PFN(size - offset - end_trunc);
816	pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
817	pfn_sb->dataoff = cpu_to_le64(offset);
818	pfn_sb->npfns = cpu_to_le64(npfns);
819	memcpy(pfn_sb->signature, sig, PFN_SIG_LEN);
820	memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
821	memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
822	pfn_sb->version_major = cpu_to_le16(1);
823	pfn_sb->version_minor = cpu_to_le16(4);
824	pfn_sb->end_trunc = cpu_to_le32(end_trunc);
825	pfn_sb->align = cpu_to_le32(nd_pfn->align);
826	if (sizeof(struct page) > MAX_STRUCT_PAGE_SIZE && page_struct_override)
827		pfn_sb->page_struct_size = cpu_to_le16(sizeof(struct page));
828	else
829		pfn_sb->page_struct_size = cpu_to_le16(MAX_STRUCT_PAGE_SIZE);
830	pfn_sb->page_size = cpu_to_le32(PAGE_SIZE);
831	checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
832	pfn_sb->checksum = cpu_to_le64(checksum);
833
834	rc = nd_pfn_clear_memmap_errors(nd_pfn);
835	if (rc)
836		return rc;
837
838	return nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0);
839}
840
841/*
842 * Determine the effective resource range and vmem_altmap from an nd_pfn
843 * instance.
844 */
845int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap)
846{
847	int rc;
848
849	if (!nd_pfn->uuid || !nd_pfn->ndns)
850		return -ENODEV;
851
852	rc = nd_pfn_init(nd_pfn);
853	if (rc)
854		return rc;
855
856	/* we need a valid pfn_sb before we can init a dev_pagemap */
857	return __nvdimm_setup_pfn(nd_pfn, pgmap);
858}
859EXPORT_SYMBOL_GPL(nvdimm_setup_pfn);