Commit 5ce9dc0f authored May 23, 2018 by Martin Schwidefsky Committed by Greg Kroah-Hartman May 26, 2018

s390/lib: use expoline for indirect branches



[ Upstream commit 97489e0663fa700d6e7febddc43b58df98d7bcda ]

The return from the memmove, memset, memcpy, __memset16, __memset32 and
__memset64 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 73bf2b1c

arch/s390/lib/mem.S

+6 −3

Original line number	Diff line number	Diff line
		@@ -5,6 +5,9 @@
		*/

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

		GEN_BR_THUNK %r14

		/*
		* memset implementation
		@@ -38,7 +41,7 @@ ENTRY(memset)
		.Lmemset_clear_rest:
		larl %r3,.Lmemset_xc
		ex %r4,0(%r3)
		br %r14
		BR_EX %r14
		.Lmemset_fill:
		stc %r3,0(%r2)
		cghi %r4,1
		@@ -55,7 +58,7 @@ ENTRY(memset)
		.Lmemset_fill_rest:
		larl %r3,.Lmemset_mvc
		ex %r4,0(%r3)
		br %r14
		BR_EX %r14
		.Lmemset_xc:
		xc 0(1,%r1),0(%r1)
		.Lmemset_mvc:
		@@ -77,7 +80,7 @@ ENTRY(memcpy)
		.Lmemcpy_rest:
		larl %r5,.Lmemcpy_mvc
		ex %r4,0(%r5)
		br %r14
		BR_EX %r14
		.Lmemcpy_loop:
		mvc 0(256,%r1),0(%r3)
		la %r1,256(%r1)