1 files changed, 33 insertions, 10 deletions

diff --git a/arch/sh/kernel/entry.S b/arch/sh/kernel/entry.S
index 97c571fbcdf1..39aaefb2d83f 100644
--- a/arch/sh/kernel/entry.S
+++ b/arch/sh/kernel/entry.S
@@ -1,9 +1,8 @@
-/* $Id: entry.S,v 1.37 2004/06/11 13:02:46 doyu Exp $
- *
+/*
  *  linux/arch/sh/entry.S
  *
  *  Copyright (C) 1999, 2000, 2002  Niibe Yutaka
- *  Copyright (C) 2003  Paul Mundt
+ *  Copyright (C) 2003 - 2006  Paul Mundt
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
@@ -78,7 +77,6 @@ OFF_TRA	=  (16*4+6*4)
 #define k3      r3
 #define k4      r4
 
-#define k_ex_code       r2_bank /* r2_bank1 */
 #define g_imask         r6      /* r6_bank1 */
 #define k_g_imask       r6_bank /* r6_bank1 */
 #define current         r7      /* r7_bank1 */
@@ -691,7 +689,7 @@ interrupt:
 0:
 #endif /* defined(CONFIG_KGDB_NMI) */
         bra     handle_exception
-         mov.l  @k2, k2
+         mov    #-1, k2         ! interrupt exception marker
 
         .align  2
 1:      .long   EXPEVT
@@ -717,8 +715,7 @@ ENTRY(handle_exception)
         add     current, k1
         mov     k1, r15         ! change to kernel stack
         !
-1:      mov     #-1, k4
-        mov.l   2f, k1
+1:      mov.l   2f, k1
         !
 #ifdef CONFIG_SH_DSP
         mov.l   r2, @-r15               ! Save r2, we need another reg
@@ -763,6 +760,8 @@ skip_save:
 #endif
         ! Save the user registers on the stack.
         mov.l   k2, @-r15       ! EXPEVT
+
+        mov     #-1, k4
         mov.l   k4, @-r15       ! set TRA (default: -1)
         !
         sts.l   macl, @-r15
@@ -797,8 +796,21 @@ skip_save:
         mov.l   r2, @-r15
         mov.l   r1, @-r15
         mov.l   r0, @-r15
-        ! Then, dispatch to the handler, according to the exception code.
-        stc     k_ex_code, r8
+
+        /*
+         * This gets a bit tricky.. in the INTEVT case we don't want to use
+         * the VBR offset as a destination in the jump call table, since all
+         * of the destinations are the same. In this case, (interrupt) sets
+         * a marker in r2 (now r2_bank since SR.RB changed), which we check
+         * to determine the exception type. For all other exceptions, we
+         * forcibly read EXPEVT from memory and fix up the jump address, in
+         * the interrupt exception case we jump to do_IRQ() and defer the
+         * INTEVT read until there. As a bonus, we can also clean up the SR.RB
+         * checks that do_IRQ() was doing..
+         */
+        stc     r2_bank, r8
+        cmp/pz  r8
+        bf      interrupt_exception
         shlr2   r8
         shlr    r8
         mov.l   4f, r9
@@ -806,6 +818,8 @@ skip_save:
         mov.l   @r9, r9
         jmp     @r9
          nop
+        rts
+         nop
 
         .align  2
 1:      .long   0x00001000      ! DSP=1
@@ -813,8 +827,17 @@ skip_save:
 3:      .long   0xcfffffff      ! RB=0, BL=0
 4:      .long   exception_handling_table
 
+interrupt_exception:
+        mov.l   1f, r9
+        jmp     @r9
+         nop
+        rts
+         nop
+
+        .align 2
+1:      .long   do_IRQ
+
         .align  2
 ENTRY(exception_none)
         rts
          nop
-