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>

3 files changed, 52 insertions, 47 deletions

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index f92adb5b0fef..e7ed39bab97d 100644
--- a/drivers/acpi/nfit.c
+++ b/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;
-                sz = buf.length;
+                union acpi_object *obj;
+                /*
+                 * 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;
@@ -1814,12 +1830,19 @@ 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;
-        ret = acpi_nfit_init(acpi_desc, buf.length);
-        if (ret) {
-                /* Merge failed, restore old nfit, and exit */
-                acpi_desc->nfit = nfit_saved;
-                dev_err(dev, "failed to merge updated NFIT\n");
+        obj = buf.pointer;
+        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);
 
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index 2ea5c0797c8f..3d549a383659 100644
--- a/drivers/acpi/nfit.h
+++ b/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;
diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
index 40ab4476c80a..51cf8256c6cd 100644
--- a/tools/testing/nvdimm/test/nfit.c
+++ b/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)
-                        + sizeof(struct acpi_nfit_system_address) * NUM_SPA
+        size_t nfit_size = 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)
-                + sizeof(struct acpi_nfit_system_address)
+        size_t nfit_size = 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 = sizeof(struct acpi_table_nfit);
+        offset = 0;
         /* spa0 (flat range with no bdw aliasing) */
         spa = nfit_buf + offset;
         spa->header.type = ACPI_NFIT_TYPE_SYSTEM_ADDRESS;