acpi/nfit, libnvdimm: Introduce nvdimm_security_ops

Some NVDIMMs, like the ones defined by the NVDIMM_FAMILY_INTEL command
set, expose a security capability to lock the DIMMs at poweroff and
require a passphrase to unlock them. The security model is derived from
ATA security. In anticipation of other DIMMs implementing a similar
scheme, and to abstract the core security implementation away from the
device-specific details, introduce nvdimm_security_ops.

Initially only a status retrieval operation, ->state(), is defined,
along with the base infrastructure and definitions for future
operations.

Signed-off-by: Dave Jiang <[email protected]>
Co-developed-by: Dan Williams <[email protected]>
Signed-off-by: Dan Williams <[email protected]>

drivers/acpi/nfit/Makefile

@@ -1,3 +1,4 @@
 obj-$(CONFIG_ACPI_NFIT) := nfit.o
 nfit-y := core.o
+nfit-y += intel.o
 nfit-$(CONFIG_X86_MCE) += mce.o

drivers/acpi/nfit/core.c

@@ -1930,6 +1930,16 @@ static void shutdown_dimm_notify(void *data)
 	mutex_unlock(&acpi_desc->init_mutex);
 }
 
+static const struct nvdimm_security_ops *acpi_nfit_get_security_ops(int family)
+{
+	switch (family) {
+	case NVDIMM_FAMILY_INTEL:
+		return intel_security_ops;
+	default:
+		return NULL;
+	}
+}
+
 static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
 {
 	struct nfit_mem *nfit_mem;
@@ -1999,7 +2009,8 @@ static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
 		nvdimm = __nvdimm_create(acpi_desc->nvdimm_bus, nfit_mem,
 				acpi_nfit_dimm_attribute_groups,
 				flags, cmd_mask, flush ? flush->hint_count : 0,
-				nfit_mem->flush_wpq, &nfit_mem->id[0]);
+				nfit_mem->flush_wpq, &nfit_mem->id[0],
+				acpi_nfit_get_security_ops(nfit_mem->family));
 		if (!nvdimm)
 			return -ENOMEM;
 

drivers/acpi/nfit/intel.c

@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2018 Intel Corporation. All rights reserved. */
+#include <linux/libnvdimm.h>
+#include <linux/ndctl.h>
+#include <linux/acpi.h>
+#include "intel.h"
+#include "nfit.h"
+
+static enum nvdimm_security_state intel_security_state(struct nvdimm *nvdimm)
+{
+	struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+	struct {
+		struct nd_cmd_pkg pkg;
+		struct nd_intel_get_security_state cmd;
+	} nd_cmd = {
+		.pkg = {
+			.nd_command = NVDIMM_INTEL_GET_SECURITY_STATE,
+			.nd_family = NVDIMM_FAMILY_INTEL,
+			.nd_size_out =
+				sizeof(struct nd_intel_get_security_state),
+			.nd_fw_size =
+				sizeof(struct nd_intel_get_security_state),
+		},
+	};
+	int rc;
+
+	if (!test_bit(NVDIMM_INTEL_GET_SECURITY_STATE, &nfit_mem->dsm_mask))
+		return -ENXIO;
+
+	rc = nvdimm_ctl(nvdimm, ND_CMD_CALL, &nd_cmd, sizeof(nd_cmd), NULL);
+	if (rc < 0)
+		return rc;
+	if (nd_cmd.cmd.status)
+		return -EIO;
+
+	/* check and see if security is enabled and locked */
+	if (nd_cmd.cmd.state & ND_INTEL_SEC_STATE_UNSUPPORTED)
+		return -ENXIO;
+	else if (nd_cmd.cmd.state & ND_INTEL_SEC_STATE_ENABLED) {
+		if (nd_cmd.cmd.state & ND_INTEL_SEC_STATE_LOCKED)
+			return NVDIMM_SECURITY_LOCKED;
+		else if (nd_cmd.cmd.state & ND_INTEL_SEC_STATE_FROZEN ||
+				nd_cmd.cmd.state & ND_INTEL_SEC_STATE_PLIMIT)
+			return NVDIMM_SECURITY_FROZEN;
+		else
+			return NVDIMM_SECURITY_UNLOCKED;
+	}
+	return NVDIMM_SECURITY_DISABLED;
+}
+
+static const struct nvdimm_security_ops __intel_security_ops = {
+	.state = intel_security_state,
+};
+const struct nvdimm_security_ops *intel_security_ops = &__intel_security_ops;

drivers/acpi/nfit/intel.h

@@ -35,6 +35,8 @@ struct nd_intel_smart {
 	};
 } __packed;
 
+extern const struct nvdimm_security_ops *intel_security_ops;
+
 #define ND_INTEL_STATUS_SIZE		4
 #define ND_INTEL_PASSPHRASE_SIZE	32