[ Upstream commit 6cf09958f32b9667bb3ebadf74367c791112771b ]
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@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com --- arch/s390/kernel/module.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c index 2fdfa64ba014..9bd1933848b8 100644 --- a/arch/s390/kernel/module.c +++ b/arch/s390/kernel/module.c @@ -473,11 +473,11 @@ 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); }