libnvdimm, btt: BTT updates for UEFI 2.7 format

The UEFI 2.7 specification defines an updated BTT metadata format,
bumping the revision to 2.0. Add support for the new format, while
retaining compatibility for the old 1.1 format.

Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Linda Knippers <linda.knippers@hpe.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/nvdimm/btt.c

@@ -37,8 +37,8 @@ static int arena_read_bytes(struct arena_info *arena, resource_size_t offset,
 	struct nd_btt *nd_btt = arena->nd_btt;
 	struct nd_namespace_common *ndns = nd_btt->ndns;
 
-	/* arena offsets are 4K from the base of the device */
-	offset += SZ_4K;
+	/* arena offsets may be shifted from the base of the device */
+	offset += arena->nd_btt->initial_offset;
 	return nvdimm_read_bytes(ndns, offset, buf, n, flags);
 }
 
@@ -48,8 +48,8 @@ static int arena_write_bytes(struct arena_info *arena, resource_size_t offset,
 	struct nd_btt *nd_btt = arena->nd_btt;
 	struct nd_namespace_common *ndns = nd_btt->ndns;
 
-	/* arena offsets are 4K from the base of the device */
-	offset += SZ_4K;
+	/* arena offsets may be shifted from the base of the device */
+	offset += arena->nd_btt->initial_offset;
 	return nvdimm_write_bytes(ndns, offset, buf, n, flags);
 }
 
@@ -576,8 +576,8 @@ static struct arena_info *alloc_arena(struct btt *btt, size_t size,
 	arena->internal_lbasize = roundup(arena->external_lbasize,
 					INT_LBASIZE_ALIGNMENT);
 	arena->nfree = BTT_DEFAULT_NFREE;
-	arena->version_major = 1;
-	arena->version_minor = 1;
+	arena->version_major = btt->nd_btt->version_major;
+	arena->version_minor = btt->nd_btt->version_minor;
 
 	if (available % BTT_PG_SIZE)
 		available -= (available % BTT_PG_SIZE);
@@ -1425,6 +1425,7 @@ int nvdimm_namespace_attach_btt(struct nd_namespace_common *ndns)
 {
 	struct nd_btt *nd_btt = to_nd_btt(ndns->claim);
 	struct nd_region *nd_region;
+	struct btt_sb *btt_sb;
 	struct btt *btt;
 	size_t rawsize;
 
@@ -1433,10 +1434,21 @@ int nvdimm_namespace_attach_btt(struct nd_namespace_common *ndns)
 		return -ENODEV;
 	}
 
-	rawsize = nvdimm_namespace_capacity(ndns) - SZ_4K;
+	btt_sb = devm_kzalloc(&nd_btt->dev, sizeof(*btt_sb), GFP_KERNEL);
+
+	/*
+	 * If this returns < 0, that is ok as it just means there wasn't
+	 * an existing BTT, and we're creating a new one. We still need to
+	 * call this as we need the version dependent fields in nd_btt to be
+	 * set correctly based on the holder class
+	 */
+	nd_btt_version(nd_btt, ndns, btt_sb);
+
+	rawsize = nvdimm_namespace_capacity(ndns) - nd_btt->initial_offset;
 	if (rawsize < ARENA_MIN_SIZE) {
 		dev_dbg(&nd_btt->dev, "%s must be at least %ld bytes\n",
-				dev_name(&ndns->dev), ARENA_MIN_SIZE + SZ_4K);
+				dev_name(&ndns->dev),
+				ARENA_MIN_SIZE + nd_btt->initial_offset);
 		return -ENXIO;
 	}
 	nd_region = to_nd_region(nd_btt->dev.parent);

drivers/nvdimm/btt.h

@@ -184,5 +184,7 @@ struct btt {
 };
 
 bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
+int nd_btt_version(struct nd_btt *nd_btt, struct nd_namespace_common *ndns,
+		struct btt_sb *btt_sb);
 
 #endif

drivers/nvdimm/btt_devs.c

@@ -260,20 +260,55 @@ bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)
 }
 EXPORT_SYMBOL(nd_btt_arena_is_valid);
 
+int nd_btt_version(struct nd_btt *nd_btt, struct nd_namespace_common *ndns,
+		struct btt_sb *btt_sb)
+{
+	if (ndns->claim_class == NVDIMM_CCLASS_BTT2) {
+		/* Probe/setup for BTT v2.0 */
+		nd_btt->initial_offset = 0;
+		nd_btt->version_major = 2;
+		nd_btt->version_minor = 0;
+		if (nvdimm_read_bytes(ndns, 0, btt_sb, sizeof(*btt_sb), 0))
+			return -ENXIO;
+		if (!nd_btt_arena_is_valid(nd_btt, btt_sb))
+			return -ENODEV;
+		if ((le16_to_cpu(btt_sb->version_major) != 2) ||
+				(le16_to_cpu(btt_sb->version_minor) != 0))
+			return -ENODEV;
+	} else {
+		/*
+		 * Probe/setup for BTT v1.1 (NVDIMM_CCLASS_NONE or
+		 * NVDIMM_CCLASS_BTT)
+		 */
+		nd_btt->initial_offset = SZ_4K;
+		nd_btt->version_major = 1;
+		nd_btt->version_minor = 1;
+		if (nvdimm_read_bytes(ndns, SZ_4K, btt_sb, sizeof(*btt_sb), 0))
+			return -ENXIO;
+		if (!nd_btt_arena_is_valid(nd_btt, btt_sb))
+			return -ENODEV;
+		if ((le16_to_cpu(btt_sb->version_major) != 1) ||
+				(le16_to_cpu(btt_sb->version_minor) != 1))
+			return -ENODEV;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(nd_btt_version);
+
 static int __nd_btt_probe(struct nd_btt *nd_btt,
 		struct nd_namespace_common *ndns, struct btt_sb *btt_sb)
 {
+	int rc;
+
 	if (!btt_sb || !ndns || !nd_btt)
 		return -ENODEV;
 
-	if (nvdimm_read_bytes(ndns, SZ_4K, btt_sb, sizeof(*btt_sb), 0))
-		return -ENXIO;
-
 	if (nvdimm_namespace_capacity(ndns) < SZ_16M)
 		return -ENXIO;
 
-	if (!nd_btt_arena_is_valid(nd_btt, btt_sb))
-		return -ENODEV;
+	rc = nd_btt_version(nd_btt, ndns, btt_sb);
+	if (rc < 0)
+		return rc;
 
 	nd_btt->lbasize = le32_to_cpu(btt_sb->external_lbasize);
 	nd_btt->uuid = kmemdup(btt_sb->uuid, 16, GFP_KERNEL);
@@ -298,6 +333,7 @@ int nd_btt_probe(struct device *dev, struct nd_namespace_common *ndns)
 	switch (ndns->claim_class) {
 	case NVDIMM_CCLASS_NONE:
 	case NVDIMM_CCLASS_BTT:
+	case NVDIMM_CCLASS_BTT2:
 		break;
 	default:
 		return -ENODEV;

drivers/nvdimm/claim.c

@@ -189,6 +189,7 @@ ssize_t nd_namespace_store(struct device *dev,
 	case NVDIMM_CCLASS_NONE:
 		break;
 	case NVDIMM_CCLASS_BTT:
+	case NVDIMM_CCLASS_BTT2:
 		if (!is_nd_btt(dev)) {
 			len = -EBUSY;
 			goto out_attach;

drivers/nvdimm/label.c

@@ -21,6 +21,7 @@
 #include "nd.h"
 
 static guid_t nvdimm_btt_guid;
+static guid_t nvdimm_btt2_guid;
 static guid_t nvdimm_pfn_guid;
 static guid_t nvdimm_dax_guid;
 
@@ -578,6 +579,8 @@ enum nvdimm_claim_class to_nvdimm_cclass(guid_t *guid)
 {
 	if (guid_equal(guid, &nvdimm_btt_guid))
 		return NVDIMM_CCLASS_BTT;
+	else if (guid_equal(guid, &nvdimm_btt2_guid))
+		return NVDIMM_CCLASS_BTT2;
 	else if (guid_equal(guid, &nvdimm_pfn_guid))
 		return NVDIMM_CCLASS_PFN;
 	else if (guid_equal(guid, &nvdimm_dax_guid))
@@ -593,6 +596,8 @@ static const guid_t *to_abstraction_guid(enum nvdimm_claim_class claim_class,
 {
 	if (claim_class == NVDIMM_CCLASS_BTT)
 		return &nvdimm_btt_guid;
+	else if (claim_class == NVDIMM_CCLASS_BTT2)
+		return &nvdimm_btt2_guid;
 	else if (claim_class == NVDIMM_CCLASS_PFN)
 		return &nvdimm_pfn_guid;
 	else if (claim_class == NVDIMM_CCLASS_DAX)
@@ -1158,6 +1163,7 @@ int nd_blk_namespace_label_update(struct nd_region *nd_region,
 int __init nd_label_init(void)
 {
 	WARN_ON(guid_parse(NVDIMM_BTT_GUID, &nvdimm_btt_guid));
+	WARN_ON(guid_parse(NVDIMM_BTT2_GUID, &nvdimm_btt2_guid));
 	WARN_ON(guid_parse(NVDIMM_PFN_GUID, &nvdimm_pfn_guid));
 	WARN_ON(guid_parse(NVDIMM_DAX_GUID, &nvdimm_dax_guid));
 

drivers/nvdimm/label.h

@@ -113,6 +113,7 @@ struct nd_namespace_label {
 };
 
 #define NVDIMM_BTT_GUID "8aed63a2-29a2-4c66-8b12-f05d15d3922a"
+#define NVDIMM_BTT2_GUID "18633bfc-1735-4217-8ac9-17239282d3f8"
 #define NVDIMM_PFN_GUID "266400ba-fb9f-4677-bcb0-968f11d0d225"
 #define NVDIMM_DAX_GUID "97a86d9c-3cdd-4eda-986f-5068b4f80088"
 

drivers/nvdimm/namespace_devs.c

@@ -1411,6 +1411,58 @@ static ssize_t dpa_extents_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(dpa_extents);
 
+static int btt_claim_class(struct device *dev)
+{
+	struct nd_region *nd_region = to_nd_region(dev->parent);
+	int i, loop_bitmask = 0;
+
+	for (i = 0; i < nd_region->ndr_mappings; i++) {
+		struct nd_mapping *nd_mapping = &nd_region->mapping[i];
+		struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
+		struct nd_namespace_index *nsindex;
+
+		nsindex = to_namespace_index(ndd, ndd->ns_current);
+		if (nsindex == NULL)
+			loop_bitmask |= 1;
+		else {
+			/* check whether existing labels are v1.1 or v1.2 */
+			if (__le16_to_cpu(nsindex->major) == 1
+					&& __le16_to_cpu(nsindex->minor) == 1)
+				loop_bitmask |= 2;
+			else
+				loop_bitmask |= 4;
+		}
+	}
+	/*
+	 * If nsindex is null loop_bitmask's bit 0 will be set, and if an index
+	 * block is found, a v1.1 label for any mapping will set bit 1, and a
+	 * v1.2 label will set bit 2.
+	 *
+	 * At the end of the loop, at most one of the three bits must be set.
+	 * If multiple bits were set, it means the different mappings disagree
+	 * about their labels, and this must be cleaned up first.
+	 *
+	 * If all the label index blocks are found to agree, nsindex of NULL
+	 * implies labels haven't been initialized yet, and when they will,
+	 * they will be of the 1.2 format, so we can assume BTT2.0
+	 *
+	 * If 1.1 labels are found, we enforce BTT1.1, and if 1.2 labels are
+	 * found, we enforce BTT2.0
+	 *
+	 * If the loop was never entered, default to BTT1.1 (legacy namespaces)
+	 */
+	switch (loop_bitmask) {
+	case 0:
+	case 2:
+		return NVDIMM_CCLASS_BTT;
+	case 1:
+	case 4:
+		return NVDIMM_CCLASS_BTT2;
+	default:
+		return -ENXIO;
+	}
+}
+
 static ssize_t holder_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -1433,7 +1485,7 @@ static ssize_t __holder_class_store(struct device *dev, const char *buf)
 		return -EBUSY;
 
 	if (strcmp(buf, "btt") == 0 || strcmp(buf, "btt\n") == 0)
-		ndns->claim_class = NVDIMM_CCLASS_BTT;
+		ndns->claim_class = btt_claim_class(dev);
 	else if (strcmp(buf, "pfn") == 0 || strcmp(buf, "pfn\n") == 0)
 		ndns->claim_class = NVDIMM_CCLASS_PFN;
 	else if (strcmp(buf, "dax") == 0 || strcmp(buf, "dax\n") == 0)
@@ -1443,6 +1495,10 @@ static ssize_t __holder_class_store(struct device *dev, const char *buf)
 	else
 		return -EINVAL;
 
+	/* btt_claim_class() could've returned an error */
+	if (ndns->claim_class < 0)
+		return ndns->claim_class;
+
 	return 0;
 }
 
@@ -1474,7 +1530,8 @@ static ssize_t holder_class_show(struct device *dev,
 	device_lock(dev);
 	if (ndns->claim_class == NVDIMM_CCLASS_NONE)
 		rc = sprintf(buf, "\n");
-	else if (ndns->claim_class == NVDIMM_CCLASS_BTT)
+	else if ((ndns->claim_class == NVDIMM_CCLASS_BTT) ||
+			(ndns->claim_class == NVDIMM_CCLASS_BTT2))
 		rc = sprintf(buf, "btt\n");
 	else if (ndns->claim_class == NVDIMM_CCLASS_PFN)
 		rc = sprintf(buf, "pfn\n");

drivers/nvdimm/nd.h

@@ -195,6 +195,9 @@ struct nd_btt {
 	u64 size;
 	u8 *uuid;
 	int id;
+	int initial_offset;
+	u16 version_major;
+	u16 version_minor;
 };
 
 enum nd_pfn_mode {

include/linux/nd.h

@@ -24,6 +24,7 @@ enum nvdimm_event {
 enum nvdimm_claim_class {
 	NVDIMM_CCLASS_NONE,
 	NVDIMM_CCLASS_BTT,
+	NVDIMM_CCLASS_BTT2,
 	NVDIMM_CCLASS_PFN,
 	NVDIMM_CCLASS_DAX,
 	NVDIMM_CCLASS_UNKNOWN,