s390/irq: store interrupt information in pt_regs

Copy the interrupt parameters from the lowcore to the pt_regs structure
in entry[64].S and reduce the arguments of the low level interrupt handler
to the pt_regs pointer only. In addition move the test-pending-interrupt
loop from do_IRQ to entry[64].S to make sure that interrupt information
is always delivered via pt_regs.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 28 insertions, 40 deletions

diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index 935d80b4e9ce..4eeb4a6bf207 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -568,7 +568,7 @@ out:
  */
 void __irq_entry do_IRQ(struct pt_regs *regs)
 {
-        struct tpi_info *tpi_info;
+        struct tpi_info *tpi_info = (struct tpi_info *) &regs->int_code;
         struct subchannel *sch;
         struct irb *irb;
         struct pt_regs *old_regs;
@@ -579,46 +579,34 @@ void __irq_entry do_IRQ(struct pt_regs *regs)
         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
                 /* Serve timer interrupts first. */
                 clock_comparator_work();
-        /*
-         * Get interrupt information from lowcore
-         */
-        tpi_info = (struct tpi_info *)&S390_lowcore.subchannel_id;
-        irb = (struct irb *)&S390_lowcore.irb;
-        do {
-                kstat_incr_irqs_this_cpu(IO_INTERRUPT, NULL);
-                if (tpi_info->adapter_IO) {
-                        do_adapter_IO(tpi_info->isc);
-                        continue;
-                }
-                sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
-                if (!sch) {
-                        /* Clear pending interrupt condition. */
-                        inc_irq_stat(IRQIO_CIO);
-                        tsch(tpi_info->schid, irb);
-                        continue;
-                }
-                spin_lock(sch->lock);
-                /* Store interrupt response block to lowcore. */
-                if (tsch(tpi_info->schid, irb) == 0) {
-                        /* Keep subchannel information word up to date. */
-                        memcpy (&sch->schib.scsw, &irb->scsw,
-                                sizeof (irb->scsw));
-                        /* Call interrupt handler if there is one. */
-                        if (sch->driver && sch->driver->irq)
-                                sch->driver->irq(sch);
-                        else
-                                inc_irq_stat(IRQIO_CIO);
-                } else
+
+        kstat_incr_irqs_this_cpu(IO_INTERRUPT, NULL);
+        irb = (struct irb *) &S390_lowcore.irb;
+        if (tpi_info->adapter_IO) {
+                do_adapter_IO(tpi_info->isc);
+                goto out;
+        }
+        sch = (struct subchannel *)(unsigned long) tpi_info->intparm;
+        if (!sch) {
+                /* Clear pending interrupt condition. */
+                inc_irq_stat(IRQIO_CIO);
+                tsch(tpi_info->schid, irb);
+                goto out;
+        }
+        spin_lock(sch->lock);
+        /* Store interrupt response block to lowcore. */
+        if (tsch(tpi_info->schid, irb) == 0) {
+                /* Keep subchannel information word up to date. */
+                memcpy (&sch->schib.scsw, &irb->scsw, sizeof (irb->scsw));
+                /* Call interrupt handler if there is one. */
+                if (sch->driver && sch->driver->irq)
+                        sch->driver->irq(sch);
+                else
                         inc_irq_stat(IRQIO_CIO);
-                spin_unlock(sch->lock);
-                /*
-                 * Are more interrupts pending?
-                 * If so, the tpi instruction will update the lowcore
-                 * to hold the info for the next interrupt.
-                 * We don't do this for VM because a tpi drops the cpu
-                 * out of the sie which costs more cycles than it saves.
-                 */
-        } while (MACHINE_IS_LPAR && tpi(NULL) != 0);
+        } else
+                inc_irq_stat(IRQIO_CIO);
+        spin_unlock(sch->lock);
+out:
         irq_exit();
         set_irq_regs(old_regs);
 }