ARC: entry: rework (non-functional)

[linux-2.6-microblaze.git] / arch / arc / include / asm / entry-arcv2.h

diff --git a/arch/arc/include/asm/entry-arcv2.h b/arch/arc/include/asm/entry-arcv2.h
index 858742f..a38ed50 100644 (file)
--- a/arch/arc/include/asm/entry-arcv2.h
+++ b/arch/arc/include/asm/entry-arcv2.h
@@ -48,14 +48,18 @@
 /*------------------------------------------------------------------------*/
 .macro INTERRUPT_PROLOGUE
 
-       ; (A) Before jumping to Interrupt Vector, hardware micro-ops did following:
+       ; Before jumping to Interrupt Vector, hardware micro-ops did following:
        ;   1. SP auto-switched to kernel mode stack
        ;   2. STATUS32.Z flag set if in U mode at time of interrupt (U:1,K:0)
        ;   3. Auto save: (mandatory) Push PC and STAT32 on stack
        ;                 hardware does even if CONFIG_ARC_IRQ_NO_AUTOSAVE
-       ;   4. Auto save: (optional) r0-r11, blink, LPE,LPS,LPC, JLI,LDI,EI
+       ;  4a. Auto save: (optional) r0-r11, blink, LPE,LPS,LPC, JLI,LDI,EI
        ;
-       ; (B) Manually saved some regs: r12,r30, sp,fp,gp, ACCL pair
+       ; Now
+       ;  4b. If Auto-save (optional) not enabled in hw, manually save them
+       ;   5. Manually save: r12,r30, sp,fp,gp, ACCL pair
+       ;
+       ; At the end, SP points to pt_regs
 
 #ifdef CONFIG_ARC_IRQ_NO_AUTOSAVE
        ; carve pt_regs on stack (case #3), PC/STAT32 already on stack
@@ -73,13 +77,14 @@
 /*------------------------------------------------------------------------*/
 .macro EXCEPTION_PROLOGUE
 
-       ; (A) Before jumping to Exception Vector, hardware micro-ops did following:
+       ; Before jumping to Exception Vector, hardware micro-ops did following:
        ;   1. SP auto-switched to kernel mode stack
        ;   2. STATUS32.Z flag set if in U mode at time of exception (U:1,K:0)
        ;
-       ; (B) Manually save the complete reg file below
+       ; Now manually save rest of reg file
+       ; At the end, SP points to pt_regs
 
-       sub     sp, sp, SZ_PT_REGS      ; carve pt_regs
+       sub     sp, sp, SZ_PT_REGS      ; carve space for pt_regs
 
        ; _HARD saves r10 clobbered by _SOFT as scratch hence comes first
 
@@ -136,8 +141,8 @@
 
        ST2     gp, fp, PT_r26          ; gp (r26), fp (r27)
 
-       st      r12, [sp, PT_sp + 4]
-       st      r30, [sp, PT_sp + 8]
+       st      r12, [sp, PT_r12]
+       st      r30, [sp, PT_r30]
 
        ; Saving pt_regs->sp correctly requires some extra work due to the way
        ; Auto stack switch works
@@ -244,7 +249,7 @@
 
        btst    r0, STATUS_U_BIT        ; Z flag set if K, used in restoring SP
 
-       ld      r10, [sp, PT_event + 4]
+       ld      r10, [sp, PT_bta]
        sr      r10, [erbta]
 
        LD2     r10, r11, PT_ret