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>

arch/s390/include/asm/lowcore.h

@@ -143,10 +143,7 @@ struct _lowcore {
 	__u32	ftrace_func;			/* 0x02f8 */
 	__u32	spinlock_lockval;		/* 0x02fc */
 
-	/* Interrupt response block */
-	__u8	irb[96];			/* 0x0300 */
-
-	__u8	pad_0x0360[0x0e00-0x0360];	/* 0x0360 */
+	__u8	pad_0x0300[0x0e00-0x0300];	/* 0x0300 */
 
 	/*
 	 * 0xe00 contains the address of the IPL Parameter Information
@@ -292,14 +289,10 @@ struct _lowcore {
 	__u32	spinlock_lockval;		/* 0x03a0 */
 	__u8	pad_0x03a0[0x0400-0x03a4];	/* 0x03a4 */
 
-	/* Interrupt response block. */
-	__u8	irb[96];			/* 0x0400 */
-	__u8	pad_0x0460[0x0480-0x0460];	/* 0x0460 */
-
 	/* Per cpu primary space access list */
-	__u32	paste[16];			/* 0x0480 */
+	__u32	paste[16];			/* 0x0400 */
 
-	__u8	pad_0x04c0[0x0e00-0x04c0];	/* 0x04c0 */
+	__u8	pad_0x04c0[0x0e00-0x0440];	/* 0x0440 */
 
 	/*
 	 * 0xe00 contains the address of the IPL Parameter Information

arch/s390/kernel/asm-offsets.c

@@ -144,7 +144,6 @@ int main(void)
 	DEFINE(__LC_MCCK_CLOCK, offsetof(struct _lowcore, mcck_clock));
 	DEFINE(__LC_MACHINE_FLAGS, offsetof(struct _lowcore, machine_flags));
 	DEFINE(__LC_FTRACE_FUNC, offsetof(struct _lowcore, ftrace_func));
-	DEFINE(__LC_IRB, offsetof(struct _lowcore, irb));
 	DEFINE(__LC_DUMP_REIPL, offsetof(struct _lowcore, ipib));
 	BLANK();
 	DEFINE(__LC_CPU_TIMER_SAVE_AREA, offsetof(struct _lowcore, cpu_timer_save_area));

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;

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));

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;
 		}

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);

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)) {

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");