The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5eda25b10297684c1f46a14199ec00210f3c346e 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
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
diff --git a/arch/s390/lib/mem.S b/arch/s390/lib/mem.S index 2311f15be9cf..40c4d59c926e 100644 --- a/arch/s390/lib/mem.S +++ b/arch/s390/lib/mem.S @@ -17,7 +17,7 @@ ENTRY(memmove) ltgr %r4,%r4 lgr %r1,%r2 - bzr %r14 + jz .Lmemmove_exit aghi %r4,-1 clgr %r2,%r3 jnh .Lmemmove_forward @@ -36,6 +36,7 @@ ENTRY(memmove) .Lmemmove_forward_remainder: larl %r5,.Lmemmove_mvc ex %r4,0(%r5) +.Lmemmove_exit: BR_EX %r14 .Lmemmove_reverse: ic %r0,0(%r4,%r3) @@ -65,7 +66,7 @@ EXPORT_SYMBOL(memmove) */ ENTRY(memset) ltgr %r4,%r4 - bzr %r14 + jz .Lmemset_exit ltgr %r3,%r3 jnz .Lmemset_fill aghi %r4,-1 @@ -80,6 +81,7 @@ ENTRY(memset) .Lmemset_clear_remainder: larl %r3,.Lmemset_xc ex %r4,0(%r3) +.Lmemset_exit: BR_EX %r14 .Lmemset_fill: cghi %r4,1 @@ -115,7 +117,7 @@ EXPORT_SYMBOL(memset) */ ENTRY(memcpy) ltgr %r4,%r4 - bzr %r14 + jz .Lmemcpy_exit aghi %r4,-1 srlg %r5,%r4,8 ltgr %r5,%r5 @@ -124,6 +126,7 @@ ENTRY(memcpy) .Lmemcpy_remainder: larl %r5,.Lmemcpy_mvc ex %r4,0(%r5) +.Lmemcpy_exit: BR_EX %r14 .Lmemcpy_loop: mvc 0(256,%r1),0(%r3) @@ -145,9 +148,9 @@ EXPORT_SYMBOL(memcpy) .macro __MEMSET bits,bytes,insn ENTRY(__memset\bits) ltgr %r4,%r4 - bzr %r14 + jz .L__memset_exit\bits cghi %r4,\bytes - je .L__memset_exit\bits + je .L__memset_store\bits aghi %r4,-(\bytes+1) srlg %r5,%r4,8 ltgr %r5,%r5 @@ -163,8 +166,9 @@ ENTRY(__memset\bits) larl %r5,.L__memset_mvc\bits ex %r4,0(%r5) BR_EX %r14 -.L__memset_exit\bits: +.L__memset_store\bits: \insn %r3,0(%r2) +.L__memset_exit\bits: BR_EX %r14 .L__memset_mvc\bits: mvc \bytes(1,%r1),0(%r1)