sh2(A) exception handler update

This patch is

By sh2
- Remove duplicate code
- Reduce stack usage
- Cleanup and little optimize

By sh2a
- Add missing handler(256 to 511)
- Use sh2a instructions handler

Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 59 insertions, 89 deletions

diff --git a/arch/sh/kernel/cpu/sh2/entry.S b/arch/sh/kernel/cpu/sh2/entry.S
index 0fc89069d8c..ee894e5a45e 100644
--- a/arch/sh/kernel/cpu/sh2/entry.S
+++ b/arch/sh/kernel/cpu/sh2/entry.S
@@ -3,7 +3,7 @@
  *
  * The SH-2 exception entry
  *
- * Copyright (C) 2005,2006 Yoshinori Sato
+ * Copyright (C) 2005-2008 Yoshinori Sato
  * Copyright (C) 2005  AXE,Inc.
  *
  * This file is subject to the terms and conditions of the GNU General Public
@@ -36,43 +36,41 @@ OFF_TRA	=  (16*4+6*4)
 #include <asm/entry-macros.S>
 
 ENTRY(exception_handler)
-        ! already saved r0/r1
+        ! stack
+        ! r0 <- point sp
+        ! r1
+        ! pc
+        ! sr
+        ! r0 = temporary
+        ! r1 = vector (pseudo EXPEVT / INTEVT / TRA)
         mov.l   r2,@-sp
         mov.l   r3,@-sp
-        mov     r0,r1
         cli
         mov.l   $cpu_mode,r2
         mov.l   @r2,r0
         mov.l   @(5*4,r15),r3   ! previous SR
-        shll2   r3              ! set "S" flag
-        rotl    r0              ! T <- "S" flag
-        rotl    r0              ! "S" flag is LSB
-        rotcr   r3              ! T -> r3:b30
-        shlr    r3
-        shlr    r0
-        bt/s    1f
-         mov.l  r3,@(5*4,r15)   ! copy cpu mode to SR
+        or      r0,r3           ! set MD
+        tst     r0,r0
+        bf/s    1f              ! previous mode check
+         mov.l  r3,@(5*4,r15)   ! update SR
         ! switch to kernel mode
-        mov     #1,r0
-        rotr    r0
-        rotr    r0
+        mov.l   __md_bit,r0
         mov.l   r0,@r2          ! enter kernel mode
         mov.l   $current_thread_info,r2
         mov.l   @r2,r2
-        mov     #0x20,r0
+        mov     #(THREAD_SIZE >> 8),r0
         shll8   r0
         add     r2,r0
         mov     r15,r2          ! r2 = user stack top
         mov     r0,r15          ! switch kernel stack
-        add     #-4,r15         ! dummy
         mov.l   r1,@-r15        ! TRA
         sts.l   macl, @-r15
         sts.l   mach, @-r15
         stc.l   gbr, @-r15
-        mov.l   @(4*4,r2),r0
-        mov.l   @(5*4,r2),r1
-        mov.l   r1,@-r15        ! original SR
+        mov.l   @(5*4,r2),r0
+        mov.l   r0,@-r15        ! original SR
         sts.l   pr,@-r15
+        mov.l   @(4*4,r2),r0
         mov.l   r0,@-r15        ! original PC
         mov     r2,r3
         add     #(4+2)*4,r3     ! rewind r0 - r3 + exception frame
@@ -88,14 +86,15 @@ ENTRY(exception_handler)
         mov.l   r6,@-r15
         mov.l   r5,@-r15
         mov.l   r4,@-r15
+        mov     r1,r9           ! save TRA
         mov     r2,r8           ! copy user -> kernel stack
-        mov.l   @r8+,r3
+        mov.l   @(0,r8),r3
         mov.l   r3,@-r15
-        mov.l   @r8+,r2
+        mov.l   @(4,r8),r2
         mov.l   r2,@-r15
-        mov.l   @r8+,r1
+        mov.l   @(12,r8),r1
         mov.l   r1,@-r15
-        mov.l   @r8+,r0
+        mov.l   @(8,r8),r0
         bra     2f
          mov.l  r0,@-r15
 1:
@@ -107,10 +106,11 @@ ENTRY(exception_handler)
         mov.l   r0,@-r15        
         mov.l   @r2+,r0         ! old R2
         mov.l   r0,@-r15        
-        mov.l   @r2+,r0         ! old R1
-        mov.l   r0,@-r15        
-        mov.l   @r2+,r0         ! old R0
+        mov.l   @(4,r2),r0      ! old R1
         mov.l   r0,@-r15        
+        mov.l   @r2,r0          ! old R0
+        mov.l   r0,@-r15
+        add     #8,r2
         mov.l   @r2+,r3         ! old PC
         mov.l   @r2+,r0         ! old SR
         add     #-4,r2          ! exception frame stub (sr)
@@ -135,14 +135,12 @@ ENTRY(exception_handler)
         mov.l   r6,@-r2
         mov.l   r5,@-r2
         mov.l   r4,@-r2
+        mov     r1,r9
         mov.l   @(OFF_R0,r15),r0
         mov.l   @(OFF_R1,r15),r1
         mov.l   @(OFF_R2,r15),r2
         mov.l   @(OFF_R3,r15),r3
 2:
-        mov     #OFF_TRA,r8
-        add     r15,r8
-        mov.l   @r8,r9  
         mov     #64,r8
         cmp/hs  r8,r9
         bt      interrupt_entry ! vec >= 64 is interrupt
@@ -150,26 +148,14 @@ ENTRY(exception_handler)
         cmp/hs  r8,r9
         bt      trap_entry      ! 64 > vec >= 32  is trap
 
-#if defined(CONFIG_SH_FPU)
-        mov     #13,r8
-        cmp/eq  r8,r9
-        bt      10f             ! fpu
-        nop
-#endif
-
         mov.l   4f,r8
         mov     r9,r4
         shll2   r9
         add     r9,r8
-        mov.l   @r8,r8
-        mov     #0,r9
-        cmp/eq  r9,r8
+        mov.l   @r8,r8          ! exception handler address
+        tst     r8,r8
         bf      3f
         mov.l   8f,r8           ! unhandled exception
-#if defined(CONFIG_SH_FPU)
-10:
-        mov.l   9f, r8          ! unhandled exception
-#endif
 3:
         mov.l   5f,r10
         jmp     @r8
@@ -188,10 +174,7 @@ interrupt_entry:
 5:      .long   ret_from_exception
 6:      .long   ret_from_irq
 7:      .long   do_IRQ
-8:      .long   do_exception_error
-#ifdef CONFIG_SH_FPU
-9:      .long   fpu_error_trap_handler
-#endif
+8:      .long   exception_error
 
 trap_entry:
         mov     #0x30,r8
@@ -200,24 +183,9 @@ trap_entry:
         add     #-0x10,r9       ! convert SH2 to SH3/4 ABI
 1:      
         shll2   r9                      ! TRA
-        mov     #OFF_TRA,r8
-        add     r15,r8
-        mov.l   r9,@r8
-        mov     r9,r8
-#ifdef CONFIG_TRACE_IRQFLAGS
-        mov.l   2f, r9
-        jsr     @r9
-         nop
-#endif
-        sti
-        bra     system_call
-         nop
+        bra     system_call     ! jump common systemcall entry
+         mov    r9,r8
         
-        .align  2
-#ifdef CONFIG_TRACE_IRQFLAGS
-2:      .long   trace_hardirqs_on
-#endif
-
 #if defined(CONFIG_SH_STANDARD_BIOS)
         /* Unwind the stack and jmp to the debug entry */
 ENTRY(sh_bios_handler)
@@ -240,7 +208,7 @@ ENTRY(sh_bios_handler)
         mov.l   @r2,r2
         stc     sr,r3
         mov.l   r2,@r0
-        mov.l   r3,@r0
+        mov.l   r3,@(4,r0)
         mov.l   r1,@(8,r0)      
         mov.l   @r15+, r0
         mov.l   @r15+, r1
@@ -272,22 +240,30 @@ ENTRY(address_error_trap_handler)
         mov.l   1f,r0
         jmp     @r0
          mov    #0,r5                           ! writeaccess is unknown
-        .align  2
 
+        .align  2
 1:      .long   do_address_error
 
 restore_all:
-        cli
-#ifdef CONFIG_TRACE_IRQFLAGS
-        mov.l   1f, r0
-        jsr     @r0
-         nop
-#endif
+        stc     sr,r0
+        or      #0xf0,r0
+        ldc     r0,sr                           ! all interrupt block (same BL = 1)
+        ! restore special register
+        ! overlap exception frame
+        mov     r15,r0
+        add     #17*4,r0
+        lds.l   @r0+,pr
+        add     #4,r0
+        ldc.l   @r0+,gbr
+        lds.l   @r0+,mach
+        lds.l   @r0+,macl
         mov     r15,r0
         mov.l   $cpu_mode,r2
         mov     #OFF_SR,r3
         mov.l   @(r0,r3),r1
-        mov.l   r1,@r2
+        mov.l   __md_bit,r3
+        and     r1,r3                           ! copy MD bit
+        mov.l   r3,@r2
         shll2   r1                              ! clear MD bit
         shlr2   r1
         mov.l   @(OFF_SP,r0),r2
@@ -297,12 +273,6 @@ restore_all:
         mov     #OFF_PC,r3
         mov.l   @(r0,r3),r1
         mov.l   r1,@r2                          ! set pc
-        add     #4*16+4,r0
-        lds.l   @r0+,pr
-        add     #4,r0                           ! skip sr
-        ldc.l   @r0+,gbr
-        lds.l   @r0+,mach
-        lds.l   @r0+,macl
         get_current_thread_info r0, r1
         mov.l   $current_thread_info,r1
         mov.l   r0,@r1
@@ -326,9 +296,8 @@ restore_all:
          nop
 
         .align 2
-#ifdef CONFIG_TRACE_IRQFLAGS
-1:     .long   trace_hardirqs_off
-#endif
+__md_bit:
+        .long   0x40000000
 $current_thread_info:
         .long   __current_thread_info
 $cpu_mode:      
diff --git a/arch/sh/kernel/cpu/sh2/ex.S b/arch/sh/kernel/cpu/sh2/ex.S
index 6d285af7846..85b0bf81fc1 100644
--- a/arch/sh/kernel/cpu/sh2/ex.S
+++ b/arch/sh/kernel/cpu/sh2/ex.S
@@ -18,16 +18,17 @@
 exception_entry:        
 no      =       0
         .rept   256
-        mov.l   r0,@-sp
-        mov     #no,r0
+        mov.l   r1,@-sp
         bra     exception_trampoline
-        and     #0xff,r0
+        mov     #no,r1
 no      =       no + 1
         .endr
 exception_trampoline:
-        mov.l   r1,@-sp
-        mov.l   $exception_handler,r1
-        jmp     @r1
+        mov.l   r0,@-sp
+        mov.l   $exception_handler,r0
+        extu.b  r1,r1
+        jmp     @r0
+          extu.w        r1,r1
 
         .align  2
 $exception_entry:
@@ -41,6 +42,6 @@ $exception_handler:
 ENTRY(vbr_base)
 vector  =       0
         .rept   256
-        .long   exception_entry + vector * 8
+        .long   exception_entry + vector * 6
 vector  =       vector + 1
         .endr