s390: convert interrupt handling to use generic hardirq

With the introduction of PCI it became apparent that s390 should
convert to generic hardirqs as too many drivers do not have the
correct dependency for GENERIC_HARDIRQS. On the architecture
level s390 does not have irq lines. It has external interrupts,
I/O interrupts and adapter interrupts. This patch hard-codes all
external interrupts as irq #1, all I/O interrupts as irq #2 and
all adapter interrupts as irq #3. The additional information from
the lowcore associated with the interrupt is stored in the
pt_regs of the interrupt frame, where the interrupt handler can
pick it up. For PCI/MSI interrupts the adapter interrupt handler
scans the relevant bit fields and calls generic_handle_irq with
the virtual irq number for the MSI interrupt.

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

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 1c039d0c24c7..980c7aa1cc5c 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -19,6 +19,7 @@
 #include <asm/unistd.h>
 #include <asm/page.h>
 #include <asm/sigp.h>
+#include <asm/irq.h>
 
 __PT_R0      =  __PT_GPRS
 __PT_R1      =  __PT_GPRS + 8
@@ -468,6 +469,11 @@ io_skip:
         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 io_loop:
         lgr     %r2,%r11                # pass pointer to pt_regs
+        lghi    %r3,IO_INTERRUPT
+        tm      __PT_INT_CODE+8(%r11),0x80      # adapter interrupt ?
+        jz      io_call
+        lghi    %r3,THIN_INTERRUPT
+io_call:
         brasl   %r14,do_IRQ
         tm      __LC_MACHINE_FLAGS+6,0x10       # MACHINE_FLAG_LPAR
         jz      io_return
@@ -623,7 +629,8 @@ ext_skip:
         TRACE_IRQS_OFF
         xc      __SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
         lgr     %r2,%r11                # pass pointer to pt_regs
-        brasl   %r14,do_extint
+        lghi    %r3,EXT_INTERRUPT
+        brasl   %r14,do_IRQ
         j       io_return
 
 /*