The patch below does not apply to the 4.16-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@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 6cf09958f32b9667bb3ebadf74367c791112771b Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Date: Fri, 20 Apr 2018 12:48:52 +0200
Subject: [PATCH] s390: correct module section names for expoline code revert
The main linker script vmlinux.lds.S for the kernel image merges
the expoline code patch tables into two section ".nospec_call_table"
and ".nospec_return_table". This is *not* done for the modules,
there the sections retain their original names as generated by gcc:
".s390_indirect_call", ".s390_return_mem" and ".s390_return_reg".
The module_finalize code has to check for the compiler generated
section names, otherwise no code patching is done. This slows down
the module code in case of "spectre_v2=off".
Cc: stable@xxxxxxxxxxxxxxx # 4.16
Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches")
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index 5a83be955c70..0dc8ac8548ee 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -465,11 +465,11 @@ int module_finalize(const Elf_Ehdr *hdr,
apply_alternatives(aseg, aseg + s->sh_size);
if (IS_ENABLED(CONFIG_EXPOLINE) &&
- (!strcmp(".nospec_call_table", secname)))
+ (!strncmp(".s390_indirect", secname, 14)))
nospec_revert(aseg, aseg + s->sh_size);
if (IS_ENABLED(CONFIG_EXPOLINE) &&
- (!strcmp(".nospec_return_table", secname)))
+ (!strncmp(".s390_return", secname, 12)))
nospec_revert(aseg, aseg + s->sh_size);
}