Re: FAILED: patch "[PATCH] s390/lib: use expoline for all bcr instructions" failed to apply to 4.4-stable tree

From: Martin Schwidefsky <schwidefsky@de.ibm.com>
To: <gregkh@linuxfoundation.org>
Cc: heiko.carstens@de.ibm.com, stable@vger.kernel.org
Subject: Re: FAILED: patch "[PATCH] s390/lib: use expoline for all bcr instructions" failed to apply to 4.4-stable tree
Date: Mon, 3 Sep 2018 18:00:15 +0200	[thread overview]
Message-ID: <20180903180015.4a64a73f@mschwideX1> (raw)
In-Reply-To: <153598046611340@kroah.com>

>From 31cda01abc7ce647bb390f9e5b57e446d8420f4b Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@de.ibm.com>
Date: Mon, 6 Aug 2018 13:49:47 +0200
Subject: [PATCH] s390/lib: use expoline for all bcr instructions

[ Upstream commit de481fa3f40d7e46f804f1b19d536b390bda5e59 ]

The memove, memset, memcpy, __memset16, __memset32 and __memset64
function have an additional indirect return branch in form of a
"bzr" instruction. These need to use expolines as well.

Cc: <stable@vger.kernel.org> # v4.17+
Fixes: 97489e0663 ("s390/lib: use expoline for indirect branches")
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/lib/mem.S | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/s390/lib/mem.S b/arch/s390/lib/mem.S
index 16c5998b9792..4254c477e8e0 100644
--- a/arch/s390/lib/mem.S
+++ b/arch/s390/lib/mem.S
@@ -26,7 +26,7 @@
  */
 ENTRY(memset)
 	ltgr	%r4,%r4
-	bzr	%r14
+	jz	.Lmemset_exit
 	ltgr	%r3,%r3
 	jnz	.Lmemset_fill
 	aghi	%r4,-1
@@ -41,12 +41,13 @@ ENTRY(memset)
 .Lmemset_clear_rest:
 	larl	%r3,.Lmemset_xc
 	ex	%r4,0(%r3)
+.Lmemset_exit:
 	BR_EX	%r14
 .Lmemset_fill:
 	stc	%r3,0(%r2)
 	cghi	%r4,1
 	lgr	%r1,%r2
-	ber	%r14
+	je	.Lmemset_fill_exit
 	aghi	%r4,-2
 	srlg	%r3,%r4,8
 	ltgr	%r3,%r3
@@ -58,6 +59,7 @@ ENTRY(memset)
 .Lmemset_fill_rest:
 	larl	%r3,.Lmemset_mvc
 	ex	%r4,0(%r3)
+.Lmemset_fill_exit:
 	BR_EX	%r14
 .Lmemset_xc:
 	xc	0(1,%r1),0(%r1)
@@ -71,7 +73,7 @@ ENTRY(memset)
  */
 ENTRY(memcpy)
 	ltgr	%r4,%r4
-	bzr	%r14
+	jz	.Lmemcpy_exit
 	aghi	%r4,-1
 	srlg	%r5,%r4,8
 	ltgr	%r5,%r5
@@ -80,6 +82,7 @@ ENTRY(memcpy)
 .Lmemcpy_rest:
 	larl	%r5,.Lmemcpy_mvc
 	ex	%r4,0(%r5)
+.Lmemcpy_exit:
 	BR_EX	%r14
 .Lmemcpy_loop:
 	mvc	0(256,%r1),0(%r3)
-- 
2.16.4
