powerpc/32s: move DABR match out of handle_page_fault

handle_page_fault() has some code dedicated to book3s/32 to
call do_break() when the DSI is a DABR match.

On other platforms, do_break() is handled separately.

Do the same for book3s/32, do it earlier in the process of DSI.

This change also avoid doing the test on ISI.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-4-npiggin@gmail.com

arch/powerpc/kernel/entry_32.S

@@ -670,10 +670,6 @@ ppc_swapcontext:
 	.globl	handle_page_fault
 handle_page_fault:
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-#ifdef CONFIG_PPC_BOOK3S_32
-	andis.  r0,r5,DSISR_DABRMATCH@h
-	bne-    handle_dabr_fault
-#endif
 	bl	do_page_fault
 	cmpwi	r3,0
 	beq+	ret_from_except
@@ -687,17 +683,6 @@ handle_page_fault:
 	bl	__bad_page_fault
 	b	ret_from_except_full
 
-#ifdef CONFIG_PPC_BOOK3S_32
-	/* We have a data breakpoint exception - handle it */
-handle_dabr_fault:
-	SAVE_NVGPRS(r1)
-	lwz	r0,_TRAP(r1)
-	clrrwi	r0,r0,1
-	stw	r0,_TRAP(r1)
-	bl      do_break
-	b	ret_from_except_full
-#endif
-
 /*
  * This routine switches between two different tasks.  The process
  * state of one is saved on its kernel stack.  Then the state

arch/powerpc/kernel/head_book3s_32.S

@@ -690,7 +690,10 @@ handle_page_fault_tramp_1:
 	lwz	r5, _DSISR(r11)
 	/* fall through */
 handle_page_fault_tramp_2:
+	andis.	r0, r5, DSISR_DABRMATCH@h
+	bne-	1f
 	EXC_XFER_LITE(0x300, handle_page_fault)
+1:	EXC_XFER_STD(0x300, do_break)
 
 #ifdef CONFIG_VMAP_STACK
 #ifdef CONFIG_PPC_BOOK3S_604