scsi: mpi3mr: Add support for DSN secure firmware check

Read PCI_EXT_CAP_ID_DSN to query security status.

The driver will throw a warning message when a non-secure type controller
is detected. The purpose of this interface is to avoid interacting with any
firmware which is not secured/signed by Broadcom.  Any tampering on
firmware component will be detected by hardware and it will be communicated
to the driver to avoid any further interaction with that component.

Link: https://lore.kernel.org/r/20210520152545.2710479-23-kashyap.desai@broadcom.com
Cc: sathya.prakash@broadcom.com
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpi3mr/mpi3mr.h

@@ -154,6 +154,15 @@ extern struct list_head mrioc_list;
 #define MPI3MR_IRQ_POLL_SLEEP			2
 #define MPI3MR_IRQ_POLL_TRIGGER_IOCOUNT		8
 
+/* Definitions for the controller security status*/
+#define MPI3MR_CTLR_SECURITY_STATUS_MASK	0x0C
+#define MPI3MR_CTLR_SECURE_DBG_STATUS_MASK	0x02
+
+#define MPI3MR_INVALID_DEVICE			0x00
+#define MPI3MR_CONFIG_SECURE_DEVICE		0x04
+#define MPI3MR_HARD_SECURE_DEVICE		0x08
+#define MPI3MR_TAMPERED_DEVICE			0x0C
+
 /* SGE Flag definition */
 #define MPI3MR_SGEFLAGS_SYSTEM_SIMPLE_END_OF_LIST \
 	(MPI3_SGE_FLAGS_ELEMENT_TYPE_SIMPLE | MPI3_SGE_FLAGS_DLAS_SYSTEM | \

drivers/scsi/mpi3mr/mpi3mr_os.c

@@ -3188,6 +3188,75 @@ static inline void mpi3mr_init_drv_cmd(struct mpi3mr_drv_cmd *cmdptr,
 	cmdptr->host_tag = host_tag;
 }
 
+/**
+ * osintfc_mrioc_security_status -Check controller secure status
+ * @pdev: PCI device instance
+ *
+ * Read the Device Serial Number capability from PCI config
+ * space and decide whether the controller is secure or not.
+ *
+ * Return: 0 on success, non-zero on failure.
+ */
+static int
+osintfc_mrioc_security_status(struct pci_dev *pdev)
+{
+	u32 cap_data;
+	int base;
+	u32 ctlr_status;
+	u32 debug_status;
+	int retval = 0;
+
+	base = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DSN);
+	if (!base) {
+		dev_err(&pdev->dev,
+		    "%s: PCI_EXT_CAP_ID_DSN is not supported\n", __func__);
+		return -1;
+	}
+
+	pci_read_config_dword(pdev, base + 4, &cap_data);
+
+	debug_status = cap_data & MPI3MR_CTLR_SECURE_DBG_STATUS_MASK;
+	ctlr_status = cap_data & MPI3MR_CTLR_SECURITY_STATUS_MASK;
+
+	switch (ctlr_status) {
+	case MPI3MR_INVALID_DEVICE:
+		dev_err(&pdev->dev,
+		    "%s: Non secure ctlr (Invalid) is detected: DID: 0x%x: SVID: 0x%x: SDID: 0x%x\n",
+		    __func__, pdev->device, pdev->subsystem_vendor,
+		    pdev->subsystem_device);
+		retval = -1;
+		break;
+	case MPI3MR_CONFIG_SECURE_DEVICE:
+		if (!debug_status)
+			dev_info(&pdev->dev,
+			    "%s: Config secure ctlr is detected\n",
+			    __func__);
+		break;
+	case MPI3MR_HARD_SECURE_DEVICE:
+		break;
+	case MPI3MR_TAMPERED_DEVICE:
+		dev_err(&pdev->dev,
+		    "%s: Non secure ctlr (Tampered) is detected: DID: 0x%x: SVID: 0x%x: SDID: 0x%x\n",
+		    __func__, pdev->device, pdev->subsystem_vendor,
+		    pdev->subsystem_device);
+		retval = -1;
+		break;
+	default:
+		retval = -1;
+			break;
+	}
+
+	if (!retval && debug_status) {
+		dev_err(&pdev->dev,
+		    "%s: Non secure ctlr (Secure Dbg) is detected: DID: 0x%x: SVID: 0x%x: SDID: 0x%x\n",
+		    __func__, pdev->device, pdev->subsystem_vendor,
+		    pdev->subsystem_device);
+		retval = -1;
+	}
+
+	return retval;
+}
+
 /**
  * mpi3mr_probe - PCI probe callback
  * @pdev: PCI device instance
@@ -3210,6 +3279,11 @@ mpi3mr_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	struct Scsi_Host *shost = NULL;
 	int retval = 0, i;
 
+	if (osintfc_mrioc_security_status(pdev)) {
+		warn_non_secure_ctlr = 1;
+		return 1; /* For Invalid and Tampered device */
+	}
+
 	shost = scsi_host_alloc(&mpi3mr_driver_template,
 	    sizeof(struct mpi3mr_ioc));
 	if (!shost) {
@@ -3326,6 +3400,9 @@ static void mpi3mr_remove(struct pci_dev *pdev)
 	unsigned long flags;
 	struct mpi3mr_tgt_dev *tgtdev, *tgtdev_next;
 
+	if (!shost)
+		return;
+
 	mrioc = shost_priv(shost);
 	while (mrioc->reset_in_progress || mrioc->is_driver_loading)
 		ssleep(1);
@@ -3444,6 +3521,9 @@ static int mpi3mr_resume(struct pci_dev *pdev)
 	pci_power_t device_state = pdev->current_state;
 	int r;
 
+	if (!shost)
+		return 0;
+
 	mrioc = shost_priv(shost);
 
 	ioc_info(mrioc, "pdev=0x%p, slot=%s, previous operating state [D%d]\n",