diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index 2215fc847fa9..ac6ddcc080d4 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -928,7 +928,7 @@ static ssize_t format_show(struct device *dev,
 {
 	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
 
-	return sprintf(buf, "0x%04x\n", be16_to_cpu(dcr->code));
+	return sprintf(buf, "0x%04x\n", le16_to_cpu(dcr->code));
 }
 static DEVICE_ATTR_RO(format);
 
@@ -961,8 +961,8 @@ static ssize_t format1_show(struct device *dev,
 				continue;
 			if (nfit_dcr->dcr->code == dcr->code)
 				continue;
-			rc = sprintf(buf, "%#x\n",
-					be16_to_cpu(nfit_dcr->dcr->code));
+			rc = sprintf(buf, "0x%04x\n",
+					le16_to_cpu(nfit_dcr->dcr->code));
 			break;
 		}
 		if (rc != ENXIO)
@@ -1131,11 +1131,11 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc,
 
 	/*
 	 * Until standardization materializes we need to consider up to 3
-	 * different command sets.  Note, that checking for function0 (bit0)
-	 * tells us if any commands are reachable through this uuid.
+	 * different command sets.  Note, that checking for zero functions
+	 * tells us if any commands might be reachable through this uuid.
 	 */
 	for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_HPE2; i++)
-		if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1))
+		if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 0))
 			break;
 
 	/* limit the supported commands to those that are publicly documented */
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index 11cb38348aef..02b9ea1e8d2e 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -53,12 +53,12 @@ enum nfit_uuids {
 };
 
 /*
- * Region format interface codes are stored as an array of bytes in the
- * NFIT DIMM Control Region structure
+ * Region format interface codes are stored with the interface as the
+ * LSB and the function as the MSB.
  */
-#define NFIT_FIC_BYTE cpu_to_be16(0x101) /* byte-addressable energy backed */
-#define NFIT_FIC_BLK cpu_to_be16(0x201) /* block-addressable non-energy backed */
-#define NFIT_FIC_BYTEN cpu_to_be16(0x301) /* byte-addressable non-energy backed */
+#define NFIT_FIC_BYTE cpu_to_le16(0x101) /* byte-addressable energy backed */
+#define NFIT_FIC_BLK cpu_to_le16(0x201) /* block-addressable non-energy backed */
+#define NFIT_FIC_BYTEN cpu_to_le16(0x301) /* byte-addressable non-energy backed */
 
 enum {
 	NFIT_BLK_READ_FLUSH = 1,
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 22c09952e177..b4de130f2d57 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -680,9 +680,6 @@ bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, u64 rev, u64 funcs)
 	u64 mask = 0;
 	union acpi_object *obj;
 
-	if (funcs == 0)
-		return false;
-
 	obj = acpi_evaluate_dsm(handle, uuid, rev, 0, NULL);
 	if (!obj)
 		return false;
@@ -695,6 +692,9 @@ bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, u64 rev, u64 funcs)
 			mask |= (((u64)obj->buffer.pointer[i]) << (i * 8));
 	ACPI_FREE(obj);
 
+	if (funcs == 0)
+		return true;
+
 	/*
 	 * Bit 0 indicates whether there's support for any functions other than
 	 * function 0 for the specified UUID and revision.
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index f7718ec685fa..cea8350fbc7e 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -344,6 +344,8 @@ struct device *nd_pfn_create(struct nd_region *nd_region)
 int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 {
 	u64 checksum, offset;
+	unsigned long align;
+	enum nd_pfn_mode mode;
 	struct nd_namespace_io *nsio;
 	struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
 	struct nd_namespace_common *ndns = nd_pfn->ndns;
@@ -386,22 +388,50 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 		return -ENXIO;
 	}
 
+	align = le32_to_cpu(pfn_sb->align);
+	offset = le64_to_cpu(pfn_sb->dataoff);
+	if (align == 0)
+		align = 1UL << ilog2(offset);
+	mode = le32_to_cpu(pfn_sb->mode);
+
 	if (!nd_pfn->uuid) {
-		/* from probe we allocate */
+		/*
+		 * When probing a namepace via nd_pfn_probe() the uuid
+		 * is NULL (see: nd_pfn_devinit()) we init settings from
+		 * pfn_sb
+		 */
 		nd_pfn->uuid = kmemdup(pfn_sb->uuid, 16, GFP_KERNEL);
 		if (!nd_pfn->uuid)
 			return -ENOMEM;
+		nd_pfn->align = align;
+		nd_pfn->mode = mode;
 	} else {
-		/* from init we validate */
+		/*
+		 * When probing a pfn / dax instance we validate the
+		 * live settings against the pfn_sb
+		 */
 		if (memcmp(nd_pfn->uuid, pfn_sb->uuid, 16) != 0)
 			return -ENODEV;
+
+		/*
+		 * If the uuid validates, but other settings mismatch
+		 * return EINVAL because userspace has managed to change
+		 * the configuration without specifying new
+		 * identification.
+		 */
+		if (nd_pfn->align != align || nd_pfn->mode != mode) {
+			dev_err(&nd_pfn->dev,
+					"init failed, settings mismatch\n");
+			dev_dbg(&nd_pfn->dev, "align: %lx:%lx mode: %d:%d\n",
+					nd_pfn->align, align, nd_pfn->mode,
+					mode);
+			return -EINVAL;
+		}
 	}
 
-	if (nd_pfn->align == 0)
-		nd_pfn->align = le32_to_cpu(pfn_sb->align);
-	if (nd_pfn->align > nvdimm_namespace_capacity(ndns)) {
+	if (align > nvdimm_namespace_capacity(ndns)) {
 		dev_err(&nd_pfn->dev, "alignment: %lx exceeds capacity %llx\n",
-				nd_pfn->align, nvdimm_namespace_capacity(ndns));
+				align, nvdimm_namespace_capacity(ndns));
 		return -EINVAL;
 	}
 
@@ -411,7 +441,6 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 	 * namespace has changed since the pfn superblock was
 	 * established.
 	 */
-	offset = le64_to_cpu(pfn_sb->dataoff);
 	nsio = to_nd_namespace_io(&ndns->dev);
 	if (offset >= resource_size(&nsio->res)) {
 		dev_err(&nd_pfn->dev, "pfn array size exceeds capacity of %s\n",
@@ -419,10 +448,11 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
 		return -EBUSY;
 	}
 
-	if ((nd_pfn->align && !IS_ALIGNED(offset, nd_pfn->align))
+	if ((align && !IS_ALIGNED(offset, align))
 			|| !IS_ALIGNED(offset, PAGE_SIZE)) {
-		dev_err(&nd_pfn->dev, "bad offset: %#llx dax disabled\n",
-				offset);
+		dev_err(&nd_pfn->dev,
+				"bad offset: %#llx dax disabled align: %#lx\n",
+				offset, align);
 		return -ENXIO;
 	}
 
@@ -502,7 +532,6 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
 	res->start += start_pad;
 	res->end -= end_trunc;
 
-	nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
 	if (nd_pfn->mode == PFN_MODE_RAM) {
 		if (offset < SZ_8K)
 			return ERR_PTR(-EINVAL);
diff --git a/fs/dax.c b/fs/dax.c
index 761495bf5eb9..e207f8f9b700 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -208,7 +208,12 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
 				dax.addr += first;
 				size = map_len - first;
 			}
-			max = min(pos + size, end);
+			/*
+			 * pos + size is one past the last offset for IO,
+			 * so pos + size can overflow loff_t at extreme offsets.
+			 * Cast to u64 to catch this and get the true minimum.
+			 */
+			max = min_t(u64, pos + size, end);
 		}
 
 		if (iov_iter_rw(iter) == WRITE) {