diff --git a/MAINTAINERS b/MAINTAINERS
index b3ea3b6..fd60784 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6160,6 +6160,7 @@
 Q:	https://patchwork.kernel.org/project/linux-nvdimm/list/
 S:	Supported
 F:	drivers/nvdimm/pmem.c
+F:	include/linux/pmem.h
 
 LINUX FOR IBM pSERIES (RS/6000)
 M:	Paul Mackerras <paulus@au.ibm.com>
diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index 2161fa1..628a42c 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -18,6 +18,7 @@
 #include <linux/list.h>
 #include <linux/acpi.h>
 #include <linux/sort.h>
+#include <linux/pmem.h>
 #include <linux/io.h>
 #include "nfit.h"
 
@@ -305,6 +306,23 @@
 	return true;
 }
 
+static bool add_flush(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_flush_address *flush)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_flush *nfit_flush = devm_kzalloc(dev, sizeof(*nfit_flush),
+			GFP_KERNEL);
+
+	if (!nfit_flush)
+		return false;
+	INIT_LIST_HEAD(&nfit_flush->list);
+	nfit_flush->flush = flush;
+	list_add_tail(&nfit_flush->list, &acpi_desc->flushes);
+	dev_dbg(dev, "%s: nfit_flush handle: %d hint_count: %d\n", __func__,
+			flush->device_handle, flush->hint_count);
+	return true;
+}
+
 static void *add_table(struct acpi_nfit_desc *acpi_desc, void *table,
 		const void *end)
 {
@@ -338,7 +356,8 @@
 			return err;
 		break;
 	case ACPI_NFIT_TYPE_FLUSH_ADDRESS:
-		dev_dbg(dev, "%s: flush\n", __func__);
+		if (!add_flush(acpi_desc, table))
+			return err;
 		break;
 	case ACPI_NFIT_TYPE_SMBIOS:
 		dev_dbg(dev, "%s: smbios\n", __func__);
@@ -389,6 +408,7 @@
 {
 	u16 dcr = __to_nfit_memdev(nfit_mem)->region_index;
 	struct nfit_memdev *nfit_memdev;
+	struct nfit_flush *nfit_flush;
 	struct nfit_dcr *nfit_dcr;
 	struct nfit_bdw *nfit_bdw;
 	struct nfit_idt *nfit_idt;
@@ -442,6 +462,14 @@
 			nfit_mem->idt_bdw = nfit_idt->idt;
 			break;
 		}
+
+		list_for_each_entry(nfit_flush, &acpi_desc->flushes, list) {
+			if (nfit_flush->flush->device_handle !=
+					nfit_memdev->memdev->device_handle)
+				continue;
+			nfit_mem->nfit_flush = nfit_flush;
+			break;
+		}
 		break;
 	}
 
@@ -978,6 +1006,24 @@
 	return mmio->base_offset + line_offset + table_offset + sub_line_offset;
 }
 
+static void wmb_blk(struct nfit_blk *nfit_blk)
+{
+
+	if (nfit_blk->nvdimm_flush) {
+		/*
+		 * The first wmb() is needed to 'sfence' all previous writes
+		 * such that they are architecturally visible for the platform
+		 * buffer flush.  Note that we've already arranged for pmem
+		 * writes to avoid the cache via arch_memcpy_to_pmem().  The
+		 * final wmb() ensures ordering for the NVDIMM flush write.
+		 */
+		wmb();
+		writeq(1, nfit_blk->nvdimm_flush);
+		wmb();
+	} else
+		wmb_pmem();
+}
+
 static u64 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
 {
 	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[DCR];
@@ -1012,7 +1058,10 @@
 		offset = to_interleave_offset(offset, mmio);
 
 	writeq(cmd, mmio->base + offset);
-	/* FIXME: conditionally perform read-back if mandated by firmware */
+	wmb_blk(nfit_blk);
+
+	if (nfit_blk->dimm_flags & ND_BLK_DCR_LATCH)
+		readq(mmio->base + offset);
 }
 
 static int acpi_nfit_blk_single_io(struct nfit_blk *nfit_blk,
@@ -1026,7 +1075,6 @@
 
 	base_offset = nfit_blk->bdw_offset + dpa % L1_CACHE_BYTES
 		+ lane * mmio->size;
-	/* TODO: non-temporal access, flush hints, cache management etc... */
 	write_blk_ctl(nfit_blk, lane, dpa, len, rw);
 	while (len) {
 		unsigned int c;
@@ -1045,13 +1093,19 @@
 		}
 
 		if (rw)
-			memcpy(mmio->aperture + offset, iobuf + copied, c);
+			memcpy_to_pmem(mmio->aperture + offset,
+					iobuf + copied, c);
 		else
-			memcpy(iobuf + copied, mmio->aperture + offset, c);
+			memcpy_from_pmem(iobuf + copied,
+					mmio->aperture + offset, c);
 
 		copied += c;
 		len -= c;
 	}
+
+	if (rw)
+		wmb_blk(nfit_blk);
+
 	rc = read_blk_stat(nfit_blk, lane) ? -EIO : 0;
 	return rc;
 }
@@ -1124,7 +1178,7 @@
 }
 
 static void __iomem *__nfit_spa_map(struct acpi_nfit_desc *acpi_desc,
-		struct acpi_nfit_system_address *spa)
+		struct acpi_nfit_system_address *spa, enum spa_map_type type)
 {
 	resource_size_t start = spa->address;
 	resource_size_t n = spa->length;
@@ -1152,8 +1206,15 @@
 	if (!res)
 		goto err_mem;
 
-	/* TODO: cacheability based on the spa type */
-	spa_map->iomem = ioremap_nocache(start, n);
+	if (type == SPA_MAP_APERTURE) {
+		/*
+		 * TODO: memremap_pmem() support, but that requires cache
+		 * flushing when the aperture is moved.
+		 */
+		spa_map->iomem = ioremap_wc(start, n);
+	} else
+		spa_map->iomem = ioremap_nocache(start, n);
+
 	if (!spa_map->iomem)
 		goto err_map;
 
@@ -1171,6 +1232,7 @@
  * nfit_spa_map - interleave-aware managed-mappings of acpi_nfit_system_address ranges
  * @nvdimm_bus: NFIT-bus that provided the spa table entry
  * @nfit_spa: spa table to map
+ * @type: aperture or control region
  *
  * In the case where block-data-window apertures and
  * dimm-control-regions are interleaved they will end up sharing a
@@ -1180,12 +1242,12 @@
  * unbound.
  */
 static void __iomem *nfit_spa_map(struct acpi_nfit_desc *acpi_desc,
-		struct acpi_nfit_system_address *spa)
+		struct acpi_nfit_system_address *spa, enum spa_map_type type)
 {
 	void __iomem *iomem;
 
 	mutex_lock(&acpi_desc->spa_map_mutex);
-	iomem = __nfit_spa_map(acpi_desc, spa);
+	iomem = __nfit_spa_map(acpi_desc, spa, type);
 	mutex_unlock(&acpi_desc->spa_map_mutex);
 
 	return iomem;
@@ -1206,12 +1268,35 @@
 	return 0;
 }
 
+static int acpi_nfit_blk_get_flags(struct nvdimm_bus_descriptor *nd_desc,
+		struct nvdimm *nvdimm, struct nfit_blk *nfit_blk)
+{
+	struct nd_cmd_dimm_flags flags;
+	int rc;
+
+	memset(&flags, 0, sizeof(flags));
+	rc = nd_desc->ndctl(nd_desc, nvdimm, ND_CMD_DIMM_FLAGS, &flags,
+			sizeof(flags));
+
+	if (rc >= 0 && flags.status == 0)
+		nfit_blk->dimm_flags = flags.flags;
+	else if (rc == -ENOTTY) {
+		/* fall back to a conservative default */
+		nfit_blk->dimm_flags = ND_BLK_DCR_LATCH;
+		rc = 0;
+	} else
+		rc = -ENXIO;
+
+	return rc;
+}
+
 static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
 		struct device *dev)
 {
 	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
 	struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
 	struct nd_blk_region *ndbr = to_nd_blk_region(dev);
+	struct nfit_flush *nfit_flush;
 	struct nfit_blk_mmio *mmio;
 	struct nfit_blk *nfit_blk;
 	struct nfit_mem *nfit_mem;
@@ -1223,8 +1308,8 @@
 	if (!nfit_mem || !nfit_mem->dcr || !nfit_mem->bdw) {
 		dev_dbg(dev, "%s: missing%s%s%s\n", __func__,
 				nfit_mem ? "" : " nfit_mem",
-				nfit_mem->dcr ? "" : " dcr",
-				nfit_mem->bdw ? "" : " bdw");
+				(nfit_mem && nfit_mem->dcr) ? "" : " dcr",
+				(nfit_mem && nfit_mem->bdw) ? "" : " bdw");
 		return -ENXIO;
 	}
 
@@ -1237,7 +1322,8 @@
 	/* map block aperture memory */
 	nfit_blk->bdw_offset = nfit_mem->bdw->offset;
 	mmio = &nfit_blk->mmio[BDW];
-	mmio->base = nfit_spa_map(acpi_desc, nfit_mem->spa_bdw);
+	mmio->base = nfit_spa_map(acpi_desc, nfit_mem->spa_bdw,
+			SPA_MAP_APERTURE);
 	if (!mmio->base) {
 		dev_dbg(dev, "%s: %s failed to map bdw\n", __func__,
 				nvdimm_name(nvdimm));
@@ -1259,7 +1345,8 @@
 	nfit_blk->cmd_offset = nfit_mem->dcr->command_offset;
 	nfit_blk->stat_offset = nfit_mem->dcr->status_offset;
 	mmio = &nfit_blk->mmio[DCR];
-	mmio->base = nfit_spa_map(acpi_desc, nfit_mem->spa_dcr);
+	mmio->base = nfit_spa_map(acpi_desc, nfit_mem->spa_dcr,
+			SPA_MAP_CONTROL);
 	if (!mmio->base) {
 		dev_dbg(dev, "%s: %s failed to map dcr\n", __func__,
 				nvdimm_name(nvdimm));
@@ -1277,6 +1364,24 @@
 		return rc;
 	}
 
+	rc = acpi_nfit_blk_get_flags(nd_desc, nvdimm, nfit_blk);
+	if (rc < 0) {
+		dev_dbg(dev, "%s: %s failed get DIMM flags\n",
+				__func__, nvdimm_name(nvdimm));
+		return rc;
+	}
+
+	nfit_flush = nfit_mem->nfit_flush;
+	if (nfit_flush && nfit_flush->flush->hint_count != 0) {
+		nfit_blk->nvdimm_flush = devm_ioremap_nocache(dev,
+				nfit_flush->flush->hint_address[0], 8);
+		if (!nfit_blk->nvdimm_flush)
+			return -ENOMEM;
+	}
+
+	if (!arch_has_pmem_api() && !nfit_blk->nvdimm_flush)
+		dev_warn(dev, "unable to guarantee persistence of writes\n");
+
 	if (mmio->line_size == 0)
 		return 0;
 
@@ -1459,6 +1564,7 @@
 	INIT_LIST_HEAD(&acpi_desc->dcrs);
 	INIT_LIST_HEAD(&acpi_desc->bdws);
 	INIT_LIST_HEAD(&acpi_desc->idts);
+	INIT_LIST_HEAD(&acpi_desc->flushes);
 	INIT_LIST_HEAD(&acpi_desc->memdevs);
 	INIT_LIST_HEAD(&acpi_desc->dimms);
 	mutex_init(&acpi_desc->spa_map_mutex);
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index 81f2e8c..79b6d83 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -40,6 +40,10 @@
 	NFIT_UUID_MAX,
 };
 
+enum {
+	ND_BLK_DCR_LATCH = 2,
+};
+
 struct nfit_spa {
 	struct acpi_nfit_system_address *spa;
 	struct list_head list;
@@ -60,6 +64,11 @@
 	struct list_head list;
 };
 
+struct nfit_flush {
+	struct acpi_nfit_flush_address *flush;
+	struct list_head list;
+};
+
 struct nfit_memdev {
 	struct acpi_nfit_memory_map *memdev;
 	struct list_head list;
@@ -77,6 +86,7 @@
 	struct acpi_nfit_system_address *spa_bdw;
 	struct acpi_nfit_interleave *idt_dcr;
 	struct acpi_nfit_interleave *idt_bdw;
+	struct nfit_flush *nfit_flush;
 	struct list_head list;
 	struct acpi_device *adev;
 	unsigned long dsm_mask;
@@ -88,6 +98,7 @@
 	struct mutex spa_map_mutex;
 	struct list_head spa_maps;
 	struct list_head memdevs;
+	struct list_head flushes;
 	struct list_head dimms;
 	struct list_head spas;
 	struct list_head dcrs;
@@ -109,7 +120,7 @@
 	struct nfit_blk_mmio {
 		union {
 			void __iomem *base;
-			void *aperture;
+			void __pmem  *aperture;
 		};
 		u64 size;
 		u64 base_offset;
@@ -123,6 +134,13 @@
 	u64 bdw_offset; /* post interleave offset */
 	u64 stat_offset;
 	u64 cmd_offset;
+	void __iomem *nvdimm_flush;
+	u32 dimm_flags;
+};
+
+enum spa_map_type {
+	SPA_MAP_CONTROL,
+	SPA_MAP_APERTURE,
 };
 
 struct nfit_spa_mapping {
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 8eb22c0..7e2c43f 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -535,8 +535,6 @@
 					__func__, dimm_name, cmd_name, i);
 			return -ENXIO;
 		}
-		if (!access_ok(VERIFY_READ, p + in_len, in_size))
-			return -EFAULT;
 		if (in_len < sizeof(in_env))
 			copy = min_t(u32, sizeof(in_env) - in_len, in_size);
 		else
@@ -557,8 +555,6 @@
 					__func__, dimm_name, cmd_name, i);
 			return -EFAULT;
 		}
-		if (!access_ok(VERIFY_WRITE, p + in_len + out_len, out_size))
-			return -EFAULT;
 		if (out_len < sizeof(out_env))
 			copy = min_t(u32, sizeof(out_env) - out_len, out_size);
 		else
@@ -570,9 +566,6 @@
 	}
 
 	buf_len = out_len + in_len;
-	if (!access_ok(VERIFY_WRITE, p, sizeof(buf_len)))
-		return -EFAULT;
-
 	if (buf_len > ND_IOCTL_MAX_BUFLEN) {
 		dev_dbg(dev, "%s:%s cmd: %s buf_len: %zu > %d\n", __func__,
 				dimm_name, cmd_name, buf_len,
@@ -706,8 +699,10 @@
 	nvdimm_major = rc;
 
 	nd_class = class_create(THIS_MODULE, "nd");
-	if (IS_ERR(nd_class))
+	if (IS_ERR(nd_class)) {
+		rc = PTR_ERR(nd_class);
 		goto err_class;
+	}
 
 	return 0;
 
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 7f8ad95..e08a6ae 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -17,11 +17,11 @@
 # define __release(x)	__context__(x,-1)
 # define __cond_lock(x,c)	((c) ? ({ __acquire(x); 1; }) : 0)
 # define __percpu	__attribute__((noderef, address_space(3)))
+# define __pmem		__attribute__((noderef, address_space(5)))
 #ifdef CONFIG_SPARSE_RCU_POINTER
 # define __rcu		__attribute__((noderef, address_space(4)))
 #else
 # define __rcu
-# define __pmem		__attribute__((noderef, address_space(5)))
 #endif
 extern void __chk_user_ptr(const volatile void __user *);
 extern void __chk_io_ptr(const volatile void __iomem *);
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index 8e9b645..f56914c 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -1,3 +1,6 @@
+ldflags-y += --wrap=ioremap_wt
+ldflags-y += --wrap=ioremap_wc
+ldflags-y += --wrap=devm_ioremap_nocache
 ldflags-y += --wrap=ioremap_cache
 ldflags-y += --wrap=ioremap_nocache
 ldflags-y += --wrap=iounmap
diff --git a/tools/testing/nvdimm/test/iomap.c b/tools/testing/nvdimm/test/iomap.c
index c85a6f6..64bfaa5 100644
--- a/tools/testing/nvdimm/test/iomap.c
+++ b/tools/testing/nvdimm/test/iomap.c
@@ -65,6 +65,21 @@
 	return fallback_fn(offset, size);
 }
 
+void __iomem *__wrap_devm_ioremap_nocache(struct device *dev,
+		resource_size_t offset, unsigned long size)
+{
+	struct nfit_test_resource *nfit_res;
+
+	rcu_read_lock();
+	nfit_res = get_nfit_res(offset);
+	rcu_read_unlock();
+	if (nfit_res)
+		return (void __iomem *) nfit_res->buf + offset
+			- nfit_res->res->start;
+	return devm_ioremap_nocache(dev, offset, size);
+}
+EXPORT_SYMBOL(__wrap_devm_ioremap_nocache);
+
 void __iomem *__wrap_ioremap_cache(resource_size_t offset, unsigned long size)
 {
 	return __nfit_test_ioremap(offset, size, ioremap_cache);
@@ -77,6 +92,18 @@
 }
 EXPORT_SYMBOL(__wrap_ioremap_nocache);
 
+void __iomem *__wrap_ioremap_wt(resource_size_t offset, unsigned long size)
+{
+	return __nfit_test_ioremap(offset, size, ioremap_wt);
+}
+EXPORT_SYMBOL(__wrap_ioremap_wt);
+
+void __iomem *__wrap_ioremap_wc(resource_size_t offset, unsigned long size)
+{
+	return __nfit_test_ioremap(offset, size, ioremap_wc);
+}
+EXPORT_SYMBOL(__wrap_ioremap_wc);
+
 void __wrap_iounmap(volatile void __iomem *addr)
 {
 	struct nfit_test_resource *nfit_res;
diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
index 4b69b83..d0bdae4 100644
--- a/tools/testing/nvdimm/test/nfit.c
+++ b/tools/testing/nvdimm/test/nfit.c
@@ -128,6 +128,8 @@
 	int num_pm;
 	void **dimm;
 	dma_addr_t *dimm_dma;
+	void **flush;
+	dma_addr_t *flush_dma;
 	void **label;
 	dma_addr_t *label_dma;
 	void **spa_set;
@@ -155,7 +157,7 @@
 	int i, rc;
 
 	if (!nfit_mem || !test_bit(cmd, &nfit_mem->dsm_mask))
-		return -ENXIO;
+		return -ENOTTY;
 
 	/* lookup label space for the given dimm */
 	for (i = 0; i < ARRAY_SIZE(handle); i++)
@@ -331,7 +333,8 @@
 			+ sizeof(struct acpi_nfit_system_address) * NUM_SPA
 			+ sizeof(struct acpi_nfit_memory_map) * NUM_MEM
 			+ sizeof(struct acpi_nfit_control_region) * NUM_DCR
-			+ sizeof(struct acpi_nfit_data_region) * NUM_BDW;
+			+ sizeof(struct acpi_nfit_data_region) * NUM_BDW
+			+ sizeof(struct acpi_nfit_flush_address) * NUM_DCR;
 	int i;
 
 	t->nfit_buf = test_alloc(t, nfit_size, &t->nfit_dma);
@@ -356,6 +359,10 @@
 		if (!t->label[i])
 			return -ENOMEM;
 		sprintf(t->label[i], "label%d", i);
+
+		t->flush[i] = test_alloc(t, 8, &t->flush_dma[i]);
+		if (!t->flush[i])
+			return -ENOMEM;
 	}
 
 	for (i = 0; i < NUM_DCR; i++) {
@@ -408,6 +415,7 @@
 	struct acpi_nfit_system_address *spa;
 	struct acpi_nfit_control_region *dcr;
 	struct acpi_nfit_data_region *bdw;
+	struct acpi_nfit_flush_address *flush;
 	unsigned int offset;
 
 	nfit_test_init_header(nfit_buf, size);
@@ -831,6 +839,39 @@
 	bdw->capacity = DIMM_SIZE;
 	bdw->start_address = 0;
 
+	offset = offset + sizeof(struct acpi_nfit_data_region) * 4;
+	/* flush0 (dimm0) */
+	flush = nfit_buf + offset;
+	flush->header.type = ACPI_NFIT_TYPE_FLUSH_ADDRESS;
+	flush->header.length = sizeof(struct acpi_nfit_flush_address);
+	flush->device_handle = handle[0];
+	flush->hint_count = 1;
+	flush->hint_address[0] = t->flush_dma[0];
+
+	/* flush1 (dimm1) */
+	flush = nfit_buf + offset + sizeof(struct acpi_nfit_flush_address) * 1;
+	flush->header.type = ACPI_NFIT_TYPE_FLUSH_ADDRESS;
+	flush->header.length = sizeof(struct acpi_nfit_flush_address);
+	flush->device_handle = handle[1];
+	flush->hint_count = 1;
+	flush->hint_address[0] = t->flush_dma[1];
+
+	/* flush2 (dimm2) */
+	flush = nfit_buf + offset + sizeof(struct acpi_nfit_flush_address) * 2;
+	flush->header.type = ACPI_NFIT_TYPE_FLUSH_ADDRESS;
+	flush->header.length = sizeof(struct acpi_nfit_flush_address);
+	flush->device_handle = handle[2];
+	flush->hint_count = 1;
+	flush->hint_address[0] = t->flush_dma[2];
+
+	/* flush3 (dimm3) */
+	flush = nfit_buf + offset + sizeof(struct acpi_nfit_flush_address) * 3;
+	flush->header.type = ACPI_NFIT_TYPE_FLUSH_ADDRESS;
+	flush->header.length = sizeof(struct acpi_nfit_flush_address);
+	flush->device_handle = handle[3];
+	flush->hint_count = 1;
+	flush->hint_address[0] = t->flush_dma[3];
+
 	acpi_desc = &t->acpi_desc;
 	set_bit(ND_CMD_GET_CONFIG_SIZE, &acpi_desc->dimm_dsm_force_en);
 	set_bit(ND_CMD_GET_CONFIG_DATA, &acpi_desc->dimm_dsm_force_en);
@@ -933,6 +974,10 @@
 				GFP_KERNEL);
 		nfit_test->dimm_dma = devm_kcalloc(dev, num, sizeof(dma_addr_t),
 				GFP_KERNEL);
+		nfit_test->flush = devm_kcalloc(dev, num, sizeof(void *),
+				GFP_KERNEL);
+		nfit_test->flush_dma = devm_kcalloc(dev, num, sizeof(dma_addr_t),
+				GFP_KERNEL);
 		nfit_test->label = devm_kcalloc(dev, num, sizeof(void *),
 				GFP_KERNEL);
 		nfit_test->label_dma = devm_kcalloc(dev, num,
@@ -943,7 +988,8 @@
 				sizeof(dma_addr_t), GFP_KERNEL);
 		if (nfit_test->dimm && nfit_test->dimm_dma && nfit_test->label
 				&& nfit_test->label_dma && nfit_test->dcr
-				&& nfit_test->dcr_dma)
+				&& nfit_test->dcr_dma && nfit_test->flush
+				&& nfit_test->flush_dma)
 			/* pass */;
 		else
 			return -ENOMEM;