s390/ipl: support NVMe IPL kernel parameters

Enable extracting of extra kernel command-line parameters
from the NVMe IPL block passed by the firmware to the kernel
at boot.

Signed-off-by: Alexander Egorenkov <[e-mail]>
Reviewed-by: Vasily Gorbik <[e-mail]>
Reviewed-by: Philipp Rudo <[e-mail]>
Signed-off-by: Vasily Gorbik <[e-mail]>

arch/s390/boot/ipl_parm.c

···
 static size_t ipl_block_get_ascii_scpdata(char *dest, size_t size,
 					  const struct ipl_parameter_block *ipb)
 {
-	size_t count;
-	size_t i;
+	const __u8 *scp_data;
+	__u32 scp_data_len;
 	int has_lowercase;
+	size_t count = 0;
+	size_t i;
 
-	count = min(size - 1, scpdata_length(ipb->fcp.scp_data,
-					     ipb->fcp.scp_data_len));
+	switch (ipb->pb0_hdr.pbt) {
+	case IPL_PBT_FCP:
+		scp_data_len = ipb->fcp.scp_data_len;
+		scp_data = ipb->fcp.scp_data;
+		break;
+	case IPL_PBT_NVME:
+		scp_data_len = ipb->nvme.scp_data_len;
+		scp_data = ipb->nvme.scp_data;
+		break;
+	default:
+		goto out;
+	}
+
+	count = min(size - 1, scpdata_length(scp_data, scp_data_len));
 	if (!count)
 		goto out;
 
 	has_lowercase = 0;
 	for (i = 0; i < count; i++) {
-		if (!isascii(ipb->fcp.scp_data[i])) {
+		if (!isascii(scp_data[i])) {
 			count = 0;
 			goto out;
 		}
-		if (!has_lowercase && islower(ipb->fcp.scp_data[i]))
+		if (!has_lowercase && islower(scp_data[i]))
 			has_lowercase = 1;
 	}
 
 	if (has_lowercase)
-		memcpy(dest, ipb->fcp.scp_data, count);
+		memcpy(dest, scp_data, count);
 	else
 		for (i = 0; i < count; i++)
-			dest[i] = tolower(ipb->fcp.scp_data[i]);
+			dest[i] = tolower(scp_data[i]);
 out:
 	dest[count] = '\0';
 	return count;
···
 			parm, COMMAND_LINE_SIZE - len - 1, &ipl_block);
 		break;
 	case IPL_PBT_FCP:
+	case IPL_PBT_NVME:
 		rc = ipl_block_get_ascii_scpdata(
 			parm, COMMAND_LINE_SIZE - len - 1, &ipl_block);
 		break;