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 467a3bf219cee12259182c5cb4821f88fd518a51 Mon Sep 17 00:00:00 2001

From: Martin Schwidefsky schwidefsky@de.ibm.com Date: Mon, 23 Apr 2018 14:31:36 +0200 Subject: [PATCH] s390/crc32-vx: use expoline for indirect branches

The return from the crc32_le_vgfm_16/crc32c_le_vgfm_16 and the crc32_be_vgfm_16 functions are done with "br %r14". These are indirect branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y.

Cc: stable@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Reviewed-by: Hendrik Brueckner brueckner@linux.vnet.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com

diff --git a/arch/s390/crypto/crc32be-vx.S b/arch/s390/crypto/crc32be-vx.S index e8077f0971f8..2bf01ba44107 100644 --- a/arch/s390/crypto/crc32be-vx.S +++ b/arch/s390/crypto/crc32be-vx.S @@ -13,6 +13,7 @@ */

#include <linux/linkage.h> +#include <asm/nospec-insn.h> #include <asm/vx-insn.h>

/* Vector register range containing CRC-32 constants */ @@ -67,6 +68,8 @@

.previous

+ GEN_BR_THUNK %r14 + .text /* * The CRC-32 function(s) use these calling conventions: @@ -203,6 +206,6 @@ ENTRY(crc32_be_vgfm_16)

.Ldone: VLGVF %r2,%v2,3 - br %r14 + BR_EX %r14

.previous diff --git a/arch/s390/crypto/crc32le-vx.S b/arch/s390/crypto/crc32le-vx.S index d8c67a58c0c5..7d6f568bd3ad 100644 --- a/arch/s390/crypto/crc32le-vx.S +++ b/arch/s390/crypto/crc32le-vx.S @@ -14,6 +14,7 @@ */

#include <linux/linkage.h> +#include <asm/nospec-insn.h> #include <asm/vx-insn.h>

/* Vector register range containing CRC-32 constants */ @@ -76,6 +77,7 @@

.previous

+ GEN_BR_THUNK %r14

.text

@@ -264,6 +266,6 @@ crc32_le_vgfm_generic:

.Ldone: VLGVF %r2,%v2,2 - br %r14 + BR_EX %r14

.previous