cxl/pmem: Add "Passphrase Secure Erase" security command support

Create callback function to support the nvdimm_security_ops() ->erase()
callback. Translate the operation to send "Passphrase Secure Erase"
security command for CXL memory device.

When the mem device is secure erased, cpu_cache_invalidate_memregion() is
called in order to invalidate all CPU caches before attempting to access
the mem device again.

See CXL 3.0 spec section 8.2.9.8.6.6 for reference.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/166983615293.2734609.10358657600295932156.stgit@djiang5-desk3.ch.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/core/mbox.c

@@ -70,6 +70,7 @@ static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
 	CXL_CMD(DISABLE_PASSPHRASE, 0x40, 0, 0),
 	CXL_CMD(FREEZE_SECURITY, 0, 0, 0),
 	CXL_CMD(UNLOCK, 0x20, 0, 0),
+	CXL_CMD(PASSPHRASE_SECURE_ERASE, 0x40, 0, 0),
 };
 
 /*

drivers/cxl/cxlmem.h

@@ -278,6 +278,7 @@ enum cxl_opcode {
 	CXL_MBOX_OP_DISABLE_PASSPHRASE	= 0x4502,
 	CXL_MBOX_OP_UNLOCK		= 0x4503,
 	CXL_MBOX_OP_FREEZE_SECURITY	= 0x4504,
+	CXL_MBOX_OP_PASSPHRASE_SECURE_ERASE	= 0x4505,
 	CXL_MBOX_OP_MAX			= 0x10000
 };
 
@@ -400,6 +401,13 @@ struct cxl_disable_pass {
 	u8 pass[NVDIMM_PASSPHRASE_LEN];
 } __packed;
 
+/* passphrase secure erase payload */
+struct cxl_pass_erase {
+	u8 type;
+	u8 reserved[31];
+	u8 pass[NVDIMM_PASSPHRASE_LEN];
+} __packed;
+
 enum {
 	CXL_PMEM_SEC_PASS_MASTER = 0,
 	CXL_PMEM_SEC_PASS_USER,

drivers/cxl/security.c

@@ -120,12 +120,41 @@ static int cxl_pmem_security_unlock(struct nvdimm *nvdimm,
 	return 0;
 }
 
+static int cxl_pmem_security_passphrase_erase(struct nvdimm *nvdimm,
+					      const struct nvdimm_key_data *key,
+					      enum nvdimm_passphrase_type ptype)
+{
+	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
+	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+	struct cxl_pass_erase erase;
+	int rc;
+
+	if (!cpu_cache_has_invalidate_memregion())
+		return -EINVAL;
+
+	erase.type = ptype == NVDIMM_MASTER ?
+		CXL_PMEM_SEC_PASS_MASTER : CXL_PMEM_SEC_PASS_USER;
+	memcpy(erase.pass, key->data, NVDIMM_PASSPHRASE_LEN);
+	/* Flush all cache before we erase mem device */
+	cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
+	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_PASSPHRASE_SECURE_ERASE,
+			       &erase, sizeof(erase), NULL, 0);
+	if (rc < 0)
+		return rc;
+
+	/* mem device erased, invalidate all CPU caches before data is read */
+	cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
+	return 0;
+}
+
 static const struct nvdimm_security_ops __cxl_security_ops = {
 	.get_flags = cxl_pmem_get_security_flags,
 	.change_key = cxl_pmem_security_change_key,
 	.disable = cxl_pmem_security_disable,
 	.freeze = cxl_pmem_security_freeze,
 	.unlock = cxl_pmem_security_unlock,
+	.erase = cxl_pmem_security_passphrase_erase,
 };
 
 const struct nvdimm_security_ops *cxl_security_ops = &__cxl_security_ops;

include/uapi/linux/cxl_mem.h

@@ -46,6 +46,7 @@
 	___C(DISABLE_PASSPHRASE, "Disable Passphrase"),			  \
 	___C(FREEZE_SECURITY, "Freeze Security"),			  \
 	___C(UNLOCK, "Unlock"),						  \
+	___C(PASSPHRASE_SECURE_ERASE, "Passphrase Secure Erase"),	  \
 	___C(MAX, "invalid / last command")
 
 #define ___C(a, b) CXL_MEM_COMMAND_ID_##a