- START_EXCEPTION(Debug)
- CRITICAL_EXCEPTION_PROLOG
-
- /*
- * If this is a single step or branch-taken exception in an
- * exception entry sequence, it was probably meant to apply to
- * the code where the exception occurred (since exception entry
- * doesn't turn off DE automatically). We simulate the effect
- * of turning off DE on entry to an exception handler by turning
- * off DE in the CSRR1 value and clearing the debug status.
- */
- mfspr r10,SPRN_DBSR /* check single-step/branch taken */
- andis. r10,r10,(DBSR_IC|DBSR_BT)@h
- beq+ 1f
- andi. r0,r9,MSR_PR /* check supervisor */
- beq 2f /* branch if we need to fix it up... */
-
- /* continue normal handling for a critical exception... */
-1: mfspr r4,SPRN_DBSR
- addi r3,r1,STACK_FRAME_OVERHEAD
- EXC_XFER_TEMPLATE(DebugException, 0x2002, \
- (MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE)), \
- NOCOPY, crit_transfer_to_handler, ret_from_crit_exc)
-
- /* here it looks like we got an inappropriate debug exception. */
-2: rlwinm r9,r9,0,~MSR_DE /* clear DE in the CSRR1 value */
- mtspr SPRN_DBSR,r10 /* clear the IC/BT debug intr status */
- /* restore state and get out */
- lwz r10,_CCR(r11)
- lwz r0,GPR0(r11)
- lwz r1,GPR1(r11)
- mtcrf 0x80,r10
- mtspr CSRR0,r12
- mtspr CSRR1,r9
- lwz r9,GPR9(r11)
-
- mtspr SPRG2,r8; /* SPRG2 only used in criticals */
- lis r8,crit_save@ha;
- lwz r10,crit_r10@l(r8)
- lwz r11,crit_r11@l(r8)
- mfspr r8,SPRG2
-
- rfci
- b .