nfit: Adjust for different _FIT and NFIT headers

When support for _FIT was added, the code presumed that the data
returned by the _FIT method is identical to the NFIT table, which
starts with an acpi_table_header.  However, the _FIT is defined
to return a data in the format of a series of NFIT type structure
entries and as a method, has an acpi_object header rather tahn
an acpi_table_header.

To address the differences, explicitly save the acpi_table_header
from the NFIT, since it is accessible through /sys, and change
the nfit pointer in the acpi_desc structure to point to the
table entries rather than the headers.

Reported-by: Jeff Moyer (jmoyer@redhat.com>
Signed-off-by: Linda Knippers <linda.knippers@hpe.com>
Acked-by: Vishal Verma <vishal.l.verma@intel.com>
[vishal: fix up unit test for new header assumptions]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/acpi/nfit.c

@@ -661,7 +661,7 @@ static ssize_t revision_show(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);
 
-	return sprintf(buf, "%d\n", acpi_desc->nfit->header.revision);
+	return sprintf(buf, "%d\n", acpi_desc->acpi_header.revision);
 }
 static DEVICE_ATTR_RO(revision);
 
@@ -1658,7 +1658,6 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, acpi_size sz)
 
 	data = (u8 *) acpi_desc->nfit;
 	end = data + sz;
-	data += sizeof(struct acpi_table_nfit);
 	while (!IS_ERR_OR_NULL(data))
 		data = add_table(acpi_desc, &prev, data, end);
 
@@ -1754,13 +1753,29 @@ static int acpi_nfit_add(struct acpi_device *adev)
 		return PTR_ERR(acpi_desc);
 	}
 
-	acpi_desc->nfit = (struct acpi_table_nfit *) tbl;
+	/*
+	 * Save the acpi header for later and then skip it,
+	 * making nfit point to the first nfit table header.
+	 */
+	acpi_desc->acpi_header = *tbl;
+	acpi_desc->nfit = (void *) tbl + sizeof(struct acpi_table_nfit);
+	sz -= sizeof(struct acpi_table_nfit);
 
 	/* Evaluate _FIT and override with that if present */
 	status = acpi_evaluate_object(adev->handle, "_FIT", NULL, &buf);
 	if (ACPI_SUCCESS(status) && buf.length > 0) {
-		acpi_desc->nfit = (struct acpi_table_nfit *)buf.pointer;
+		union acpi_object *obj;
-		sz = buf.length;
+		/*
+		 * Adjust for the acpi_object header of the _FIT
+		 */
+		obj = buf.pointer;
+		if (obj->type == ACPI_TYPE_BUFFER) {
+			acpi_desc->nfit =
+				(struct acpi_nfit_header *)obj->buffer.pointer;
+			sz = obj->buffer.length;
+		} else
+			dev_dbg(dev, "%s invalid type %d, ignoring _FIT\n",
+				 __func__, (int) obj->type);
 	}
 
 	rc = acpi_nfit_init(acpi_desc, sz);
@@ -1783,7 +1798,8 @@ static void acpi_nfit_notify(struct acpi_device *adev, u32 event)
 {
 	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
 	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
-	struct acpi_table_nfit *nfit_saved;
+	struct acpi_nfit_header *nfit_saved;
+	union acpi_object *obj;
 	struct device *dev = &adev->dev;
 	acpi_status status;
 	int ret;
@@ -1814,13 +1830,20 @@ static void acpi_nfit_notify(struct acpi_device *adev, u32 event)
 	}
 
 	nfit_saved = acpi_desc->nfit;
-	acpi_desc->nfit = (struct acpi_table_nfit *)buf.pointer;
+	obj = buf.pointer;
-	ret = acpi_nfit_init(acpi_desc, buf.length);
+	if (obj->type == ACPI_TYPE_BUFFER) {
+		acpi_desc->nfit =
+			(struct acpi_nfit_header *)obj->buffer.pointer;
+		ret = acpi_nfit_init(acpi_desc, obj->buffer.length);
 		if (ret) {
 			/* Merge failed, restore old nfit, and exit */
 			acpi_desc->nfit = nfit_saved;
 			dev_err(dev, "failed to merge updated NFIT\n");
 		}
+	} else {
+		/* Bad _FIT, restore old nfit */
+		dev_err(dev, "Invalid _FIT\n");
+	}
 	kfree(buf.pointer);
 
  out_unlock:

drivers/acpi/nfit.h

@@ -96,7 +96,8 @@ struct nfit_mem {
 
 struct acpi_nfit_desc {
 	struct nvdimm_bus_descriptor nd_desc;
-	struct acpi_table_nfit *nfit;
+	struct acpi_table_header acpi_header;
+	struct acpi_nfit_header *nfit;
 	struct mutex spa_map_mutex;
 	struct mutex init_mutex;
 	struct list_head spa_maps;

tools/testing/nvdimm/test/nfit.c

@@ -420,8 +420,7 @@ static struct nfit_test_resource *nfit_test_lookup(resource_size_t addr)
 
 static int nfit_test0_alloc(struct nfit_test *t)
 {
-	size_t nfit_size = sizeof(struct acpi_table_nfit)
+	size_t nfit_size = sizeof(struct acpi_nfit_system_address) * NUM_SPA
-			+ 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
@@ -471,8 +470,7 @@ static int nfit_test0_alloc(struct nfit_test *t)
 
 static int nfit_test1_alloc(struct nfit_test *t)
 {
-	size_t nfit_size = sizeof(struct acpi_table_nfit)
+	size_t nfit_size = sizeof(struct acpi_nfit_system_address)
-		+ sizeof(struct acpi_nfit_system_address)
 		+ sizeof(struct acpi_nfit_memory_map)
 		+ sizeof(struct acpi_nfit_control_region);
 
@@ -488,39 +486,24 @@ static int nfit_test1_alloc(struct nfit_test *t)
 	return 0;
 }
 
-static void nfit_test_init_header(struct acpi_table_nfit *nfit, size_t size)
-{
-	memcpy(nfit->header.signature, ACPI_SIG_NFIT, 4);
-	nfit->header.length = size;
-	nfit->header.revision = 1;
-	memcpy(nfit->header.oem_id, "LIBND", 6);
-	memcpy(nfit->header.oem_table_id, "TEST", 5);
-	nfit->header.oem_revision = 1;
-	memcpy(nfit->header.asl_compiler_id, "TST", 4);
-	nfit->header.asl_compiler_revision = 1;
-}
-
 static void nfit_test0_setup(struct nfit_test *t)
 {
 	struct nvdimm_bus_descriptor *nd_desc;
 	struct acpi_nfit_desc *acpi_desc;
 	struct acpi_nfit_memory_map *memdev;
 	void *nfit_buf = t->nfit_buf;
-	size_t size = t->nfit_size;
 	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);
-
 	/*
 	 * spa0 (interleave first half of dimm0 and dimm1, note storage
 	 * does not actually alias the related block-data-window
 	 * regions)
 	 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit);
+	spa = nfit_buf;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_PM), 16);
@@ -533,7 +516,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	 * does not actually alias the related block-data-window
 	 * regions)
 	 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit) + sizeof(*spa);
+	spa = nfit_buf + sizeof(*spa);
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_PM), 16);
@@ -542,7 +525,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	spa->length = SPA1_SIZE;
 
 	/* spa2 (dcr0) dimm0 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit) + sizeof(*spa) * 2;
+	spa = nfit_buf + sizeof(*spa) * 2;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_DCR), 16);
@@ -551,7 +534,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	spa->length = DCR_SIZE;
 
 	/* spa3 (dcr1) dimm1 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit) + sizeof(*spa) * 3;
+	spa = nfit_buf + sizeof(*spa) * 3;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_DCR), 16);
@@ -560,7 +543,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	spa->length = DCR_SIZE;
 
 	/* spa4 (dcr2) dimm2 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit) + sizeof(*spa) * 4;
+	spa = nfit_buf + sizeof(*spa) * 4;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_DCR), 16);
@@ -569,7 +552,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	spa->length = DCR_SIZE;
 
 	/* spa5 (dcr3) dimm3 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit) + sizeof(*spa) * 5;
+	spa = nfit_buf + sizeof(*spa) * 5;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_DCR), 16);
@@ -578,7 +561,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	spa->length = DCR_SIZE;
 
 	/* spa6 (bdw for dcr0) dimm0 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit) + sizeof(*spa) * 6;
+	spa = nfit_buf + sizeof(*spa) * 6;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_BDW), 16);
@@ -587,7 +570,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	spa->length = DIMM_SIZE;
 
 	/* spa7 (bdw for dcr1) dimm1 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit) + sizeof(*spa) * 7;
+	spa = nfit_buf + sizeof(*spa) * 7;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_BDW), 16);
@@ -596,7 +579,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	spa->length = DIMM_SIZE;
 
 	/* spa8 (bdw for dcr2) dimm2 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit) + sizeof(*spa) * 8;
+	spa = nfit_buf + sizeof(*spa) * 8;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_BDW), 16);
@@ -605,7 +588,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	spa->length = DIMM_SIZE;
 
 	/* spa9 (bdw for dcr3) dimm3 */
-	spa = nfit_buf + sizeof(struct acpi_table_nfit) + sizeof(*spa) * 9;
+	spa = nfit_buf + sizeof(*spa) * 9;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;
 	spa->header.length = sizeof(*spa);
 	memcpy(spa->range_guid, to_nfit_uuid(NFIT_SPA_BDW), 16);
@@ -613,7 +596,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	spa->address = t->dimm_dma[3];
 	spa->length = DIMM_SIZE;
 
-	offset = sizeof(struct acpi_table_nfit) + sizeof(*spa) * 10;
+	offset = sizeof(*spa) * 10;
 	/* mem-region0 (spa0, dimm0) */
 	memdev = nfit_buf + offset;
 	memdev->header.type = ACPI_NFIT_TYPE_MEMORY_MAP;
@@ -1100,15 +1083,13 @@ static void nfit_test0_setup(struct nfit_test *t)
 
 static void nfit_test1_setup(struct nfit_test *t)
 {
-	size_t size = t->nfit_size, offset;
+	size_t offset;
 	void *nfit_buf = t->nfit_buf;
 	struct acpi_nfit_memory_map *memdev;
 	struct acpi_nfit_control_region *dcr;
 	struct acpi_nfit_system_address *spa;
 
-	nfit_test_init_header(nfit_buf, size);
+	offset = 0;
-
-	offset = sizeof(struct acpi_table_nfit);
 	/* spa0 (flat range with no bdw aliasing) */
 	spa = nfit_buf + offset;
 	spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;