nfit: disable vendor specific commands

Module option to limit userspace to the publicly defined command set.
For cases where private DIMM commands may be interfering with the
kernel's handling of DIMM state this option can be set to block vendor
specific commands.

Cc: Jerry Hoemann <jerry.hoemann@hpe.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/acpi/nfit.c

@@ -45,6 +45,11 @@ module_param(scrub_overflow_abort, uint, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(scrub_overflow_abort,
 		"Number of times we overflow ARS results before abort");
 
+static bool disable_vendor_specific;
+module_param(disable_vendor_specific, bool, S_IRUGO);
+MODULE_PARM_DESC(disable_vendor_specific,
+		"Limit commands to the publicly specified set\n");
+
 static struct workqueue_struct *nfit_wq;
 
 struct nfit_table_prev {
@@ -989,13 +994,17 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc,
 
 	/* limit the supported commands to those that are publicly documented */
 	nfit_mem->family = i;
-	if (nfit_mem->family == NVDIMM_FAMILY_INTEL)
+	if (nfit_mem->family == NVDIMM_FAMILY_INTEL) {
 		dsm_mask = 0x3fe;
-	else if (nfit_mem->family == NVDIMM_FAMILY_HPE1)
+		if (disable_vendor_specific)
+			dsm_mask &= ~(1 << ND_CMD_VENDOR);
+	} else if (nfit_mem->family == NVDIMM_FAMILY_HPE1)
 		dsm_mask = 0x1c3c76;
-	else if (nfit_mem->family == NVDIMM_FAMILY_HPE2)
+	else if (nfit_mem->family == NVDIMM_FAMILY_HPE2) {
 		dsm_mask = 0x1fe;
-	else {
+		if (disable_vendor_specific)
+			dsm_mask &= ~(1 << 8);
+	} else {
 		dev_err(dev, "unknown dimm command family\n");
 		nfit_mem->family = -1;
 		return force_enable_dimms ? 0 : -ENODEV;