s390/lowcore: replace lowcore irb array with a per-cpu variable

Remove the 96-byte irb array from the lowcore and create a per-cpu
variable instead. That way we will pick up any change in the definition
of the struct irb automatically.

Acked-By: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

6 files changed, 13 insertions, 8 deletions

diff --git a/drivers/s390/cio/ccwreq.c b/drivers/s390/cio/ccwreq.c
index fc5fb51d9bc..07676c22d51 100644
--- a/drivers/s390/cio/ccwreq.c
+++ b/drivers/s390/cio/ccwreq.c
@@ -252,7 +252,7 @@ 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 irb *irb = &__get_cpu_var(cio_irb);
 	struct ccw_request *req = &cdev->private->req;
 	enum io_status status;
 	int rc = -EOPNOTSUPP;
diff --git a/drivers/s390/cio/chsc_sch.c b/drivers/s390/cio/chsc_sch.c
index 1d3661af7bd..3d22d2a4ce1 100644
--- a/drivers/s390/cio/chsc_sch.c
+++ b/drivers/s390/cio/chsc_sch.c
@@ -58,7 +58,7 @@ static void chsc_subchannel_irq(struct subchannel *sch)
 {
 	struct chsc_private *private = dev_get_drvdata(&sch->dev);
 	struct chsc_request *request = private->request;
-	struct irb *irb = (struct irb *)&S390_lowcore.irb;
+	struct irb *irb = &__get_cpu_var(cio_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 9e058c4657a..77f9c92df4b 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -46,6 +46,9 @@ debug_info_t *cio_debug_msg_id;
 debug_info_t *cio_debug_trace_id;
 debug_info_t *cio_debug_crw_id;
 
+DEFINE_PER_CPU_ALIGNED(struct irb, cio_irb);
+EXPORT_PER_CPU_SYMBOL(cio_irb);
+
 /*
  * Function: cio_debug_init
  * Initializes three debug logs for common I/O:
@@ -560,7 +563,7 @@ static irqreturn_t do_cio_interrupt(int irq, void *dummy)
 
 	__this_cpu_write(s390_idle.nohz_delay, 1);
 	tpi_info = (struct tpi_info *) &get_irq_regs()->int_code;
-	irb = (struct irb *) &S390_lowcore.irb;
+	irb = &__get_cpu_var(cio_irb);
 	sch = (struct subchannel *)(unsigned long) tpi_info->intparm;
 	if (!sch) {
 		/* Clear pending interrupt condition. */
@@ -609,7 +612,7 @@ void cio_tsch(struct subchannel *sch)
 	struct irb *irb;
 	int irq_context;
 
-	irb = (struct irb *)&S390_lowcore.irb;
+	irb = &__get_cpu_var(cio_irb);
 	/* Store interrupt response block to lowcore. */
 	if (tsch(sch->schid, irb) != 0)
 		/* Not status pending or not operational. */
@@ -746,7 +749,7 @@ __clear_io_subchannel_easy(struct subchannel_id schid)
 		struct tpi_info ti;
 
 		if (tpi(&ti)) {
-			tsch(ti.schid, (struct irb *)&S390_lowcore.irb);
+			tsch(ti.schid, &__get_cpu_var(cio_irb));
 			if (schid_equal(&ti.schid, &schid))
 				return 0;
 		}
diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index d42f67412bd..a01376ae174 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -102,6 +102,8 @@ struct subchannel {
 	struct schib_config config;
 } __attribute__ ((aligned(8)));
 
+DECLARE_PER_CPU(struct irb, cio_irb);
+
 #define to_subchannel(n) container_of(n, struct subchannel, dev)
 
 extern int cio_validate_subchannel (struct subchannel *, struct subchannel_id);
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index c7638c54325..0bc902b3cd8 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -739,7 +739,7 @@ ccw_device_irq(struct ccw_device *cdev, enum dev_event dev_event)
 	struct irb *irb;
 	int is_cmd;
 
-	irb = (struct irb *)&S390_lowcore.irb;
+	irb = &__get_cpu_var(cio_irb);
 	is_cmd = !scsw_is_tm(&irb->scsw);
 	/* Check for unsolicited interrupt. */
 	if (!scsw_is_solicited(&irb->scsw)) {
@@ -805,7 +805,7 @@ ccw_device_w4sense(struct ccw_device *cdev, enum dev_event dev_event)
 {
 	struct irb *irb;
 
-	irb = (struct irb *)&S390_lowcore.irb;
+	irb = &__get_cpu_var(cio_irb);
 	/* Check for unsolicited interrupt. */
 	if (scsw_stctl(&irb->scsw) ==
 	    (SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) {
diff --git a/drivers/s390/cio/eadm_sch.c b/drivers/s390/cio/eadm_sch.c
index 3a2ee4a740b..c4f7bf3e24c 100644
--- a/drivers/s390/cio/eadm_sch.c
+++ b/drivers/s390/cio/eadm_sch.c
@@ -134,7 +134,7 @@ static void eadm_subchannel_irq(struct subchannel *sch)
 {
 	struct eadm_private *private = get_eadm_private(sch);
 	struct eadm_scsw *scsw = &sch->schib.scsw.eadm;
-	struct irb *irb = (struct irb *)&S390_lowcore.irb;
+	struct irb *irb = &__get_cpu_var(cio_irb);
 	int error = 0;
 
 	EADM_LOG(6, "irq");