3 files changed, 46 insertions, 20 deletions

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 548a18916a31..a831d18596a5 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -1080,28 +1080,10 @@ void __init chsc_init_cleanup(void)
 	free_page((unsigned long)sei_page);
 }
 
-int chsc_enable_facility(int operation_code)
+int __chsc_enable_facility(struct chsc_sda_area *sda_area, int operation_code)
 {
-	unsigned long flags;
 	int ret;
-	struct {
-		struct chsc_header request;
-		u8 reserved1:4;
-		u8 format:4;
-		u8 reserved2;
-		u16 operation_code;
-		u32 reserved3;
-		u32 reserved4;
-		u32 operation_data_area[252];
-		struct chsc_header response;
-		u32 reserved5:4;
-		u32 format2:4;
-		u32 reserved6:24;
-	} __attribute__ ((packed)) *sda_area;
 
-	spin_lock_irqsave(&chsc_page_lock, flags);
-	memset(chsc_page, 0, PAGE_SIZE);
-	sda_area = chsc_page;
 	sda_area->request.length = 0x0400;
 	sda_area->request.code = 0x0031;
 	sda_area->operation_code = operation_code;
@@ -1119,10 +1101,25 @@ int chsc_enable_facility(int operation_code)
 	default:
 		ret = chsc_error_from_response(sda_area->response.code);
 	}
+out:
+	return ret;
+}
+
+int chsc_enable_facility(int operation_code)
+{
+	struct chsc_sda_area *sda_area;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&chsc_page_lock, flags);
+	memset(chsc_page, 0, PAGE_SIZE);
+	sda_area = chsc_page;
+
+	ret = __chsc_enable_facility(sda_area, operation_code);
 	if (ret != 0)
 		CIO_CRW_EVENT(2, "chsc: sda (oc=%x) failed (rc=%04x)\n",
 			      operation_code, sda_area->response.code);
-out:
+
 	spin_unlock_irqrestore(&chsc_page_lock, flags);
 	return ret;
 }
diff --git a/drivers/s390/cio/chsc.h b/drivers/s390/cio/chsc.h
index 76c9b50700b2..0de134c3a204 100644
--- a/drivers/s390/cio/chsc.h
+++ b/drivers/s390/cio/chsc.h
@@ -115,6 +115,20 @@ struct chsc_scpd {
 	u8 data[PAGE_SIZE - 20];
 } __attribute__ ((packed));
 
+struct chsc_sda_area {
+	struct chsc_header request;
+	u8 :4;
+	u8 format:4;
+	u8 :8;
+	u16 operation_code;
+	u32 :32;
+	u32 :32;
+	u32 operation_data_area[252];
+	struct chsc_header response;
+	u32 :4;
+	u32 format2:4;
+	u32 :24;
+} __packed __aligned(PAGE_SIZE);
 
 extern int chsc_get_ssd_info(struct subchannel_id schid,
 			     struct chsc_ssd_info *ssd);
@@ -122,6 +136,7 @@ extern int chsc_determine_css_characteristics(void);
 extern int chsc_init(void);
 extern void chsc_init_cleanup(void);
 
+int __chsc_enable_facility(struct chsc_sda_area *sda_area, int operation_code);
 extern int chsc_enable_facility(int);
 struct channel_subsystem;
 extern int chsc_secm(struct channel_subsystem *, int);
diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index b5620e818d6b..690b8547e828 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -925,18 +925,32 @@ void reipl_ccw_dev(struct ccw_dev_id *devid)
 
 int __init cio_get_iplinfo(struct cio_iplinfo *iplinfo)
 {
+	static struct chsc_sda_area sda_area __initdata;
 	struct subchannel_id schid;
 	struct schib schib;
 
 	schid = *(struct subchannel_id *)&S390_lowcore.subchannel_id;
 	if (!schid.one)
 		return -ENODEV;
+
+	if (schid.ssid) {
+		/*
+		 * Firmware should have already enabled MSS but whoever started
+		 * the kernel might have initiated a channel subsystem reset.
+		 * Ensure that MSS is enabled.
+		 */
+		memset(&sda_area, 0, sizeof(sda_area));
+		if (__chsc_enable_facility(&sda_area, CHSC_SDA_OC_MSS))
+			return -ENODEV;
+	}
 	if (stsch_err(schid, &schib))
 		return -ENODEV;
 	if (schib.pmcw.st != SUBCHANNEL_TYPE_IO)
 		return -ENODEV;
 	if (!schib.pmcw.dnv)
 		return -ENODEV;
+
+	iplinfo->ssid = schid.ssid;
 	iplinfo->devno = schib.pmcw.dev;
 	iplinfo->is_qdio = schib.pmcw.qf;
 	return 0;