acpi/nfit, libnvdimm/security: Add security DSM overwrite support

Add support for the NVDIMM_FAMILY_INTEL "ovewrite" capability as
described by the Intel DSM spec v1.7. This will allow triggering of
overwrite on Intel NVDIMMs. The overwrite operation can take tens of
minutes. When the overwrite DSM is issued successfully, the NVDIMMs will
be unaccessible. The kernel will do backoff polling to detect when the
overwrite process is completed. According to the DSM spec v1.7, the 128G
NVDIMMs can take up to 15mins to perform overwrite and larger DIMMs will
take longer.

Given that overwrite puts the DIMM in an indeterminate state until it
completes introduce the NDD_SECURITY_OVERWRITE flag to prevent other
operations from executing when overwrite is happening. The
NDD_WORK_PENDING flag is added to denote that there is a device reference
on the nvdimm device for an async workqueue thread context.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index b4b633ccfbe9..952d688982d8 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -21,6 +21,7 @@
 extern struct list_head nvdimm_bus_list;
 extern struct mutex nvdimm_bus_list_mutex;
 extern int nvdimm_major;
+extern struct workqueue_struct *nvdimm_wq;
 
 struct nvdimm_bus {
 	struct nvdimm_bus_descriptor *nd_desc;
@@ -45,7 +46,10 @@ struct nvdimm {
 	struct {
 		const struct nvdimm_security_ops *ops;
 		enum nvdimm_security_state state;
+		unsigned int overwrite_tmo;
+		struct kernfs_node *overwrite_state;
 	} sec;
+	struct delayed_work dwork;
 };
 
 static inline enum nvdimm_security_state nvdimm_security_state(
@@ -62,6 +66,8 @@ int nvdimm_security_disable(struct nvdimm *nvdimm, unsigned int keyid);
 int nvdimm_security_update(struct nvdimm *nvdimm, unsigned int keyid,
 		unsigned int new_keyid);
 int nvdimm_security_erase(struct nvdimm *nvdimm, unsigned int keyid);
+int nvdimm_security_overwrite(struct nvdimm *nvdimm, unsigned int keyid);
+void nvdimm_security_overwrite_query(struct work_struct *work);
 #else
 static inline int nvdimm_security_disable(struct nvdimm *nvdimm,
 		unsigned int keyid)
@@ -77,6 +83,14 @@ static inline int nvdimm_security_erase(struct nvdimm *nvdimm, unsigned int keyi
 {
 	return -EOPNOTSUPP;
 }
+static inline int nvdimm_security_overwrite(struct nvdimm *nvdimm,
+		unsigned int keyid)
+{
+	return -EOPNOTSUPP;
+}
+static inline void nvdimm_security_overwrite_query(struct work_struct *work)
+{
+}
 #endif
 
 /**