libnvdimm/namespace: Enforce memremap_compat_align()

The pmem driver on PowerPC crashes with the following signature when
instantiating misaligned namespaces that map their capacity via
memremap_pages().

    BUG: Unable to handle kernel data access at 0xc001000406000000
    Faulting instruction address: 0xc000000000090790
    NIP [c000000000090790] arch_add_memory+0xc0/0x130
    LR [c000000000090744] arch_add_memory+0x74/0x130
    Call Trace:
     arch_add_memory+0x74/0x130 (unreliable)
     memremap_pages+0x74c/0xa30
     devm_memremap_pages+0x3c/0xa0
     pmem_attach_disk+0x188/0x770
     nvdimm_bus_probe+0xd8/0x470

With the assumption that only memremap_pages() has alignment
constraints, enforce memremap_compat_align() for
pmem_should_map_pages(), nd_pfn, and nd_dax cases. This includes
preventing the creation of namespaces where the base address is
misaligned and cases there infoblock padding parameters are invalid.

Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Fixes: a3619190d62e ("libnvdimm/pfn: stop padding pmem namespaces to section alignment")
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 032dc61..77e211c 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -10,6 +10,7 @@
 #include <linux/nd.h>
 #include "nd-core.h"
 #include "pmem.h"
+#include "pfn.h"
 #include "nd.h"
 
 static void namespace_io_release(struct device *dev)
@@ -1739,6 +1740,22 @@ struct nd_namespace_common *nvdimm_namespace_common_probe(struct device *dev)
 		return ERR_PTR(-ENODEV);
 	}
 
+	/*
+	 * Note, alignment validation for fsdax and devdax mode
+	 * namespaces happens in nd_pfn_validate() where infoblock
+	 * padding parameters can be applied.
+	 */
+	if (pmem_should_map_pages(dev)) {
+		struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
+		struct resource *res = &nsio->res;
+
+		if (!IS_ALIGNED(res->start | (res->end + 1),
+					memremap_compat_align())) {
+			dev_err(&ndns->dev, "%pr misaligned, unable to map\n", res);
+			return ERR_PTR(-EOPNOTSUPP);
+		}
+	}
+
 	if (is_namespace_pmem(&ndns->dev)) {
 		struct nd_namespace_pmem *nspm;