From ebe864b55304f74c4e1a8b6c899e34446b2be424 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 17 Sep 2025 09:04:01 -0700 Subject: objtool/klp: Add post-link subcommand to finalize livepatch modules Livepatch needs some ELF magic which linkers don't like: - Two relocation sections (.rela*, .klp.rela*) for the same text section. - Use of SHN_LIVEPATCH to mark livepatch symbols. Unfortunately linkers tend to mangle such things. To work around that, klp diff generates a linker-compliant intermediate binary which encodes the relevant KLP section/reloc/symbol metadata. After module linking, the .ko then needs to be converted to an actual livepatch module. Introduce a new klp post-link subcommand to do so. Acked-by: Petr Mladek Tested-by: Joe Lawrence Signed-off-by: Josh Poimboeuf --- tools/objtool/include/objtool/klp.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'tools/objtool/include') diff --git a/tools/objtool/include/objtool/klp.h b/tools/objtool/include/objtool/klp.h index 07928fac059b..ad830a7ce55b 100644 --- a/tools/objtool/include/objtool/klp.h +++ b/tools/objtool/include/objtool/klp.h @@ -2,6 +2,9 @@ #ifndef _OBJTOOL_KLP_H #define _OBJTOOL_KLP_H +#define SHF_RELA_LIVEPATCH 0x00100000 +#define SHN_LIVEPATCH 0xff20 + /* * __klp_objects and __klp_funcs are created by klp diff and used by the patch * module init code to build the klp_patch, klp_object and klp_func structs @@ -27,5 +30,6 @@ struct klp_reloc { }; int cmd_klp_diff(int argc, const char **argv); +int cmd_klp_post_link(int argc, const char **argv); #endif /* _OBJTOOL_KLP_H */ -- cgit v1.2.3