Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 46/74] s390: correct module section names for expoline code revert | Date | Fri, 27 Apr 2018 15:58:36 +0200 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Martin Schwidefsky <schwidefsky@de.ibm.com>
[ 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/s390/kernel/module.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/s390/kernel/module.c +++ b/arch/s390/kernel/module.c @@ -477,11 +477,11 @@ 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); }
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