Subject: [PATCH v4 01/21] powerpc/32s: Do DABR match out of handle_page_fault()

From: Nicholas Piggin <[email-masked]>
Date: Sat, 2 Jan 2021 22:24:48 +1000

From: Christophe Leroy <[email-masked]>

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 <[email-masked]>
---
 arch/powerpc/kernel/entry_32.S       | 15 ---------------
 arch/powerpc/kernel/head_book3s_32.S |  3 +++
 2 files changed, 3 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 1c9b0ccc2172..238eacfda7b0 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/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
diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index 349bf3f0c3af..fc9a12768a14 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -680,7 +680,10 @@ 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
 .macro save_regs_thread		thread
-- 
2.23.0