linux-kernel - [RFC PATCH v2 07/10] powerpc/8xx: split breakpoint exception

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Message-Id: <b86ace4b0c34da731859fae0f44dbc079b603b09.1567245404.git.christophe.leroy@c-s.fr>
Date:   Sat, 31 Aug 2019 10:18:31 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, npiggin@...il.com,
        dja@...ens.net
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [RFC PATCH v2 07/10] powerpc/8xx: split breakpoint exception

Breakpoint exception is big.

Split it to support future growth on exception prolog.

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/kernel/head_8xx.S | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index d194cff6528b..2fa02ae7a88c 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -497,14 +497,7 @@ DARFixed:/* Return from dcbx instruction bug workaround */
  * support of breakpoints and such.  Someday I will get around to
  * using them.
  */
-	. = 0x1c00
-DataBreakpoint:
-	EXCEPTION_PROLOG_0
-	mfspr	r11, SPRN_SRR0
-	cmplwi	cr0, r11, (.Ldtlbie - PAGE_OFFSET)@l
-	cmplwi	cr7, r11, (.Litlbie - PAGE_OFFSET)@l
-	beq-	cr0, 11f
-	beq-	cr7, 11f
+do_databreakpoint:
 	EXCEPTION_PROLOG_1
 	EXCEPTION_PROLOG_2
 	addi	r3,r1,STACK_FRAME_OVERHEAD
@@ -512,7 +505,15 @@ DataBreakpoint:
 	stw	r4,_DAR(r11)
 	mfspr	r5,SPRN_DSISR
 	EXC_XFER_STD(0x1c00, do_break)
-11:
+
+	. = 0x1c00
+DataBreakpoint:
+	EXCEPTION_PROLOG_0
+	mfspr	r11, SPRN_SRR0
+	cmplwi	cr0, r11, (.Ldtlbie - PAGE_OFFSET)@l
+	cmplwi	cr7, r11, (.Litlbie - PAGE_OFFSET)@l
+	cror	4*cr0+eq, 4*cr0+eq, 4*cr7+eq
+	bne	do_databreakpoint
 	mtcr	r10
 	mfspr	r10, SPRN_SPRG_SCRATCH0
 	mfspr	r11, SPRN_SPRG_SCRATCH1
-- 
2.13.3