[S390] Cleanup struct _lowcore usage and defines.

Use asm offsets to make sure the offset defines to struct _lowcore and
its layout don't get out of sync.
Also add a BUILD_BUG_ON() which checks that the size of the structure
is sane.
And while being at it change those sites which use odd casts to access
the current lowcore. These should use S390_lowcore instead.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

4 files changed, 10 insertions, 10 deletions

diff --git a/drivers/s390/cio/ccwreq.c b/drivers/s390/cio/ccwreq.c
index 7a28a3029a3f..37df42af05ec 100644
--- a/drivers/s390/cio/ccwreq.c
+++ b/drivers/s390/cio/ccwreq.c
@@ -224,8 +224,8 @@ static void ccwreq_log_status(struct ccw_device *cdev, enum io_status status)
  */
 void ccw_request_handler(struct ccw_device *cdev)
 {
+	struct irb *irb = (struct irb *)&S390_lowcore.irb;
 	struct ccw_request *req = &cdev->private->req;
-	struct irb *irb = (struct irb *) __LC_IRB;
 	enum io_status status;
 	int rc = -EOPNOTSUPP;
 
diff --git a/drivers/s390/cio/chsc_sch.c b/drivers/s390/cio/chsc_sch.c
index df7388e88d31..852612f5dba0 100644
--- a/drivers/s390/cio/chsc_sch.c
+++ b/drivers/s390/cio/chsc_sch.c
@@ -51,7 +51,7 @@ static void chsc_subchannel_irq(struct subchannel *sch)
 {
 	struct chsc_private *private = sch->private;
 	struct chsc_request *request = private->request;
-	struct irb *irb = (struct irb *)__LC_IRB;
+	struct irb *irb = (struct irb *)&S390_lowcore.irb;
 
 	CHSC_LOG(4, "irb");
 	CHSC_LOG_HEX(4, irb, sizeof(*irb));
diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index f9d8c7936a09..f736cdcf08ad 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -625,8 +625,8 @@ void __irq_entry do_IRQ(struct pt_regs *regs)
 	/*
 	 * Get interrupt information from lowcore
 	 */
-	tpi_info = (struct tpi_info *) __LC_SUBCHANNEL_ID;
-	irb = (struct irb *) __LC_IRB;
+	tpi_info = (struct tpi_info *)&S390_lowcore.subchannel_id;
+	irb = (struct irb *)&S390_lowcore.irb;
 	do {
 		kstat_cpu(smp_processor_id()).irqs[IO_INTERRUPT]++;
 		/*
@@ -682,10 +682,10 @@ static int cio_tpi(void)
 	struct irb *irb;
 	int irq_context;
 
-	tpi_info = (struct tpi_info *) __LC_SUBCHANNEL_ID;
+	tpi_info = (struct tpi_info *)&S390_lowcore.subchannel_id;
 	if (tpi(NULL) != 1)
 		return 0;
-	irb = (struct irb *) __LC_IRB;
+	irb = (struct irb *)&S390_lowcore.irb;
 	/* Store interrupt response block to lowcore. */
 	if (tsch(tpi_info->schid, irb) != 0)
 		/* Not status pending or not operational. */
@@ -885,7 +885,7 @@ __clear_io_subchannel_easy(struct subchannel_id schid)
 		struct tpi_info ti;
 
 		if (tpi(&ti)) {
-			tsch(ti.schid, (struct irb *)__LC_IRB);
+			tsch(ti.schid, (struct irb *)&S390_lowcore.irb);
 			if (schid_equal(&ti.schid, &schid))
 				return 0;
 		}
@@ -1083,7 +1083,7 @@ int __init cio_get_iplinfo(struct cio_iplinfo *iplinfo)
 	struct subchannel_id schid;
 	struct schib schib;
 
-	schid = *(struct subchannel_id *)__LC_SUBCHANNEL_ID;
+	schid = *(struct subchannel_id *)&S390_lowcore.subchannel_id;
 	if (!schid.one)
 		return -ENODEV;
 	if (stsch(schid, &schib))
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index 2cb01861ce34..c56ab94612f9 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -690,7 +690,7 @@ ccw_device_irq(struct ccw_device *cdev, enum dev_event dev_event)
 	struct irb *irb;
 	int is_cmd;
 
-	irb = (struct irb *) __LC_IRB;
+	irb = (struct irb *)&S390_lowcore.irb;
 	is_cmd = !scsw_is_tm(&irb->scsw);
 	/* Check for unsolicited interrupt. */
 	if (!scsw_is_solicited(&irb->scsw)) {
@@ -755,7 +755,7 @@ ccw_device_w4sense(struct ccw_device *cdev, enum dev_event dev_event)
 {
 	struct irb *irb;
 
-	irb = (struct irb *) __LC_IRB;
+	irb = (struct irb *)&S390_lowcore.irb;
 	/* Check for unsolicited interrupt. */
 	if (scsw_stctl(&irb->scsw) ==
 	    (SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) {