net/smc: manage system EID in SMC stack instead of ISM driver

The System EID (SEID) is an internal EID that is used by the SMCv2
software stack that has a predefined and constant value representing
the s390 physical machine that the OS is executing on. So it should
be managed by SMC stack instead of ISM driver and be consistent for
all ISMv2 device (including virtual ISM devices) on s390 architecture.

Suggested-by: Alexandra Winter <[e-mail]>
Signed-off-by: Wen Gu <[e-mail]>
Reviewed-and-tested-by: Wenjia Zhang <[e-mail]>
Reviewed-by: Alexandra Winter <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/s390/net/ism.h

···
  */
 #define ISM_DMB_WORD_OFFSET	1
 #define ISM_DMB_BIT_OFFSET	(ISM_DMB_WORD_OFFSET * 32)
-#define ISM_IDENT_MASK		0x00FFFF
 
 #define ISM_REG_SBA	0x1
 #define ISM_REG_IEQ	0x2
···
 
 #define ISM_CREATE_REQ(dmb, idx, sf, offset)		\
 	((dmb) | (idx) << 24 | (sf) << 23 | (offset))
-
-struct ism_systemeid {
-	u8	seid_string[24];
-	u8	serial_number[4];
-	u8	type[4];
-};
 
 static inline void __ism_read_cmd(struct ism_dev *ism, void *data,
 				  unsigned long offset, unsigned long len)

drivers/s390/net/ism_drv.c

···
 						/* a list for fast mapping  */
 static u8 max_client;
 static DEFINE_MUTEX(clients_lock);
+static bool ism_v2_capable;
 struct ism_dev_list {
 	struct list_head list;
 	struct mutex mutex; /* protects ism device list */
···
 }
 EXPORT_SYMBOL_GPL(ism_move);
 
-static struct ism_systemeid SYSTEM_EID = {
-	.seid_string = "IBM-SYSZ-ISMSEID00000000",
-	.serial_number = "0000",
-	.type = "0000",
-};
-
-static void ism_create_system_eid(void)
-{
-	struct cpuid id;
-	u16 ident_tail;
-	char tmp[5];
-
-	get_cpu_id(&id);
-	ident_tail = (u16)(id.ident & ISM_IDENT_MASK);
-	snprintf(tmp, 5, "%04X", ident_tail);
-	memcpy(&SYSTEM_EID.serial_number, tmp, 4);
-	snprintf(tmp, 5, "%04X", id.machine);
-	memcpy(&SYSTEM_EID.type, tmp, 4);
-}
-
-u8 *ism_get_seid(void)
-{
-	return SYSTEM_EID.seid_string;
-}
-EXPORT_SYMBOL_GPL(ism_get_seid);
-
 static void ism_handle_event(struct ism_dev *ism)
 {
 	struct ism_event *entry;
···
 
 	if (!ism_add_vlan_id(ism, ISM_RESERVED_VLANID))
 		/* hardware is V2 capable */
-		ism_create_system_eid();
+		ism_v2_capable = true;
+	else
+		ism_v2_capable = false;
 
 	mutex_lock(&ism_dev_list.mutex);
 	mutex_lock(&clients_lock);
···
 	}
 	mutex_unlock(&clients_lock);
 
-	if (SYSTEM_EID.serial_number[0] != '0' ||
-	    SYSTEM_EID.type[0] != '0')
+	if (ism_v2_capable)
 		ism_del_vlan_id(ism, ISM_RESERVED_VLANID);
 	unregister_ieq(ism);
 	unregister_sba(ism);
···
 
 static int smcd_supports_v2(void)
 {
-	return SYSTEM_EID.serial_number[0] != '0' ||
-		SYSTEM_EID.type[0] != '0';
+	return ism_v2_capable;
 }
 
 static u64 ism_get_local_gid(struct ism_dev *ism)
···
 	.signal_event = smcd_signal_ieq,
 	.move_data = smcd_move,
 	.supports_v2 = smcd_supports_v2,
-	.get_system_eid = ism_get_seid,
 	.get_local_gid = smcd_get_local_gid,
 	.get_chid = smcd_get_chid,
 	.get_dev = smcd_get_dev,

include/linux/ism.h

···
 int  ism_unregister_dmb(struct ism_dev *dev, struct ism_dmb *dmb);
 int  ism_move(struct ism_dev *dev, u64 dmb_tok, unsigned int idx, bool sf,
 	      unsigned int offset, void *data, unsigned int size);
-u8  *ism_get_seid(void);
 
 const struct smcd_ops *ism_get_smcd_ops(void);
 

include/net/smc.h

···
 			 bool sf, unsigned int offset, void *data,
 			 unsigned int size);
 	int (*supports_v2)(void);
-	u8* (*get_system_eid)(void);
 	void (*get_local_gid)(struct smcd_dev *dev, struct smcd_gid *gid);
 	u16 (*get_chid)(struct smcd_dev *dev);
 	struct device* (*get_dev)(struct smcd_dev *dev);

net/smc/smc_ism.c

···
 };
 #endif
 
+static void smc_ism_create_system_eid(void)
+{
+	struct smc_ism_seid *seid =
+		(struct smc_ism_seid *)smc_ism_v2_system_eid;
+#if IS_ENABLED(CONFIG_S390)
+	struct cpuid id;
+	u16 ident_tail;
+	char tmp[5];
+
+	memcpy(seid->seid_string, "IBM-SYSZ-ISMSEID00000000", 24);
+	get_cpu_id(&id);
+	ident_tail = (u16)(id.ident & SMC_ISM_IDENT_MASK);
+	snprintf(tmp, 5, "%04X", ident_tail);
+	memcpy(seid->serial_number, tmp, 4);
+	snprintf(tmp, 5, "%04X", id.machine);
+	memcpy(seid->type, tmp, 4);
+#else
+	memset(seid, 0, SMC_MAX_EID_LEN);
+#endif
+}
+
 /* Test if an ISM communication is possible - same CPC */
 int smc_ism_cantalk(struct smcd_gid *peer_gid, unsigned short vlan_id,
 		    struct smcd_dev *smcd)
···
 
 	mutex_lock(&smcd_dev_list.mutex);
 	if (list_empty(&smcd_dev_list.list)) {
-		u8 *system_eid = NULL;
-
-		system_eid = smcd->ops->get_system_eid();
-		if (smcd->ops->supports_v2()) {
+		if (smcd->ops->supports_v2())
 			smc_ism_v2_capable = true;
-			memcpy(smc_ism_v2_system_eid, system_eid,
-			       SMC_MAX_EID_LEN);
-		}
 	}
 	/* sort list: devices without pnetid before devices with pnetid */
 	if (smcd->pnetid[0])
···
 {
 	int rc = 0;
 
-#if IS_ENABLED(CONFIG_ISM)
 	smc_ism_v2_capable = false;
-	memset(smc_ism_v2_system_eid, 0, SMC_MAX_EID_LEN);
+	smc_ism_create_system_eid();
 
+#if IS_ENABLED(CONFIG_ISM)
 	rc = ism_register_client(&smc_ism_client);
 #endif
 	return rc;

net/smc/smc_ism.h

···
 #include "smc.h"
 
 #define SMC_VIRTUAL_ISM_CHID_MASK	0xFF00
+#define SMC_ISM_IDENT_MASK		0x00FFFF
 
 struct smcd_dev_list {	/* List of SMCD devices */
 	struct list_head list;
···
 	struct list_head list;
 	unsigned short vlanid;		/* Vlan id */
 	refcount_t refcnt;		/* Reference count */
+};
+
+struct smc_ism_seid {
+	u8 seid_string[24];
+	u8 serial_number[4];
+	u8 type[4];
 };
 
 struct smcd_dev;