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, 9 insertions, 3 deletions

diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index be7a408be7a1..5ca70b4b72cb 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -18,6 +18,7 @@
 #include <asm/unistd.h>
 #include <asm/page.h>
 #include <asm/sigp.h>
+#include <asm/irq.h>
 
 __PT_R0      =  __PT_GPRS
 __PT_R1      =  __PT_GPRS + 4
@@ -435,6 +436,11 @@ io_skip:
 io_loop:
         l       %r1,BASED(.Ldo_IRQ)
         lr      %r2,%r11                # pass pointer to pt_regs
+        lhi     %r3,IO_INTERRUPT
+        tm      __PT_INT_CODE+8(%r11),0x80      # adapter interrupt ?
+        jz      io_call
+        lhi     %r3,THIN_INTERRUPT
+io_call:
         basr    %r14,%r1                # call do_IRQ
         tm      __LC_MACHINE_FLAGS+2,0x10       # MACHINE_FLAG_LPAR
         jz      io_return
@@ -584,9 +590,10 @@ ext_skip:
         mvc     __PT_INT_CODE(4,%r11),__LC_EXT_CPU_ADDR
         mvc     __PT_INT_PARM(4,%r11),__LC_EXT_PARAMS
         TRACE_IRQS_OFF
+        l       %r1,BASED(.Ldo_IRQ)
         lr      %r2,%r11                # pass pointer to pt_regs
-        l       %r1,BASED(.Ldo_extint)
-        basr    %r14,%r1                # call do_extint
+        lhi     %r3,EXT_INTERRUPT
+        basr    %r14,%r1                # call do_IRQ
         j       io_return
 
 /*
@@ -902,7 +909,6 @@ cleanup_idle_wait:
 .Ldo_machine_check:     .long   s390_do_machine_check
 .Lhandle_mcck:          .long   s390_handle_mcck
 .Ldo_IRQ:               .long   do_IRQ
-.Ldo_extint:            .long   do_extint
 .Ldo_signal:            .long   do_signal
 .Ldo_notify_resume:     .long   do_notify_resume
 .Ldo_per_trap:          .long   do_per_trap