Hi, George, On Fri, Jul 24, 2026 at 7:41 PM George Guo <[email protected]> wrote: > > This series adds LoongArch support for the klp-build livepatch tooling, > enabling automated livepatch module generation using objtool on > LoongArch. > > It is based on Josh Poimboeuf's klp-build series [1] (see base-commit > below, unchanged from v1-v3) and extends it with the LoongArch-specific > objtool and build pieces, plus the toolchain and relocation fixes > required to make livepatch modules load, generate, and run correctly > under both GCC and Clang. > > Collaboration > ============= > > Patch 1 ("objtool/LoongArch: Add arch_adjusted_addend() for KLP support") > and patch 7 ("LoongArch: Add livepatch build (KLP) support") overlap with > WangYuli's earlier LoongArch KLP work [2]. Both now carry > Co-developed-by/Signed-off-by: WangYuli. > > WangYuli, please check that the attribution is recorded correctly. If you > consider any other patch in this series to overlap your work, point it out > and I will add the tags in the final version. > > Overview > ======== > > - Patches 1-8: the LoongArch objtool hooks, special-section marking > (including the inline ALTERNATIVE() replacement), the combined > -fPIC / -mno-direct-extern-access build fix, EFI linking, the syscall > patching macro, and wiring up LoongArch klp-build. > - Patches 9-14: objtool/klp-diff fixes found by running the full > klp-build flow under GCC and Clang. > > Testing > ======= > > The klp-build integration tests were run on LoongArch under both GCC and > Clang: cmdline-string, proc-version, data-new, gcc-static-local-var-6, > syscall, new-globals, new-function, and shadow-newpid. All of them now > generate a livepatch module, load it, and run. > > new-function and shadow-newpid did not build under Clang before this > version; the new objtool/klp-diff patches fix the Clang-specific > failures the suite surfaced. Joe Lawrence's test case was also > reproduced end to end on a Clang-built kernel in a VM (patch load, > tracepoint toggle, clean unload). > > Changes since v3 [3] > ==================== > > - Merged the two build-flag patches (-mno-direct-extern-access and > -fPIC) into one. The combined patch is one complete thought: for > LoongArch KLP builds, replace the arch's KBUILD_CFLAGS_KERNEL (dropping > -fPIE and -mdirect-extern-access) and add -fPIC via KCFLAGS. (Joe > Lawrence) > - Moved the LoongArch config checks (CONFIG_RELOCATABLE, > CONFIG_AS_HAS_EXPLICIT_RELOCS) into validate_config(). (Joe Lawrence) > - Patch 4 (EFI): fixed the changelog wording and added the > "/* from the EFI stub */" comment on the wildcard, matching arm64 and > riscv. (Joe Lawrence) > - Patch 6 (syscall macro): pad the line continuations with tabs. (Joe > Lawrence) > - New patch 12: enable inline ALTERNATIVE() cloning. Joe hit > "can't find new instruction" livepatching a function that contains an > ALTERNATIVE(). Mark the .subsection 1 replacement with > ANNOTATE_DATA_SPECIAL (patch 2) and define ARCH_HAS_INLINE_ALTS for > LoongArch objtool (patch 12), mirroring arm64. (Joe Lawrence) > - New patch 13: keep the tablejump annotation table entries. klp-diff > dropped the table-side word of each .discard.tablejump_annotate pair, > which crashed objtool on the patch module. > - New patch 14: rewrite PC-relative data references to GOT. File-local > static data uses a direct pcalau12i/addi.d pair that cannot reach > vmlinux from the far livepatch module; convert it to a GOT-indirect > load when the klp relocation is created. This affects GCC and Clang. > > On patch 11 (fold paired ADD/SUB relocations): Clang's integrated > assembler emits the ADD64/SUB64 pair for a "sym - ." whose symbol is > undefined in the current object, where GAS with -mthin-add-sub emits a > single R_LARCH_64_PCREL. Reported to LLVM as issue #210052 [4]. The fold > is kept regardless, since shipping Clang emits the pair. > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux.git/log/?h=klp-build-arm64 > [2] > https://lore.kernel.org/loongarch/[email protected]/ > [3] https://lore.kernel.org/all/[email protected]/ > [4] https://github.com/llvm/llvm-project/issues/210052 > > George Guo (14): > objtool/LoongArch: Add arch_adjusted_addend() for KLP support > LoongArch: Mark special sections for KLP support > livepatch/klp-build: use -fPIC and drop direct-extern-access on > LoongArch > LoongArch: Fix EFI linking with -fdata-sections > objtool/klp: Add LoongArch jump opcode bytes support > klp-build: Add LoongArch syscall patching macro > LoongArch: Add livepatch build (KLP) support > LoongArch: Select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY > objtool/klp: Convert local label references > objtool/klp: Fix ANNOTATE_DATA_SPECIAL parsing for local label > references > objtool/klp: Fold LoongArch paired ADD/SUB relocations into PCREL > objtool/LoongArch: Enable inline alternative cloning for KLP > objtool/klp: Keep LoongArch tablejump annotation table entries > objtool/klp: Rewrite PC-relative data references to GOT on LoongArch
It is better to reorganize this series like this: objtool/klp: Convert local label references objtool/klp: Fix ANNOTATE_DATA_SPECIAL parsing for local label references objtool/klp: Add LoongArch jump opcode bytes support objtool/klp: Fold LoongArch paired ADD/SUB relocations into PCREL objtool/klp: Keep LoongArch tablejump annotation table entries objtool/klp: Rewrite PC-relative data references to GOT on LoongArch objtool/LoongArch: Add arch_adjusted_addend() for KLP support objtool/LoongArch: Enable inline alternative cloning for KLP klp-build: use -fPIC and drop direct-extern-access on LoongArch klp-build: Add LoongArch syscall patching macro LoongArch: Mark special sections for KLP support LoongArch: Fix EFI linking with -fdata-sections LoongArch: Add livepatch build (KLP) support LoongArch: Select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY Huacai > > arch/loongarch/Kconfig | 2 + > arch/loongarch/include/asm/alternative-asm.h | 10 +- > arch/loongarch/include/asm/alternative.h | 11 +- > arch/loongarch/include/asm/asm-extable.h | 10 +- > arch/loongarch/include/asm/bug.h | 1 + > arch/loongarch/include/asm/jump_label.h | 2 + > arch/loongarch/kernel/asm-offsets.c | 18 ++ > arch/loongarch/kernel/vmlinux.lds.S | 2 +- > include/linux/livepatch_helpers.h | 22 ++ > scripts/livepatch/klp-build | 43 +++- > tools/arch/loongarch/include/asm/inst.h | 11 + > tools/objtool/Makefile | 3 +- > tools/objtool/arch/loongarch/decode.c | 212 ++++++++++++++++++ > .../objtool/arch/loongarch/include/arch/elf.h | 35 +++ > tools/objtool/klp-diff.c | 105 ++++++++- > 15 files changed, 473 insertions(+), 14 deletions(-) > > > base-commit: 85afaba140a4b9f20fe8c8a64b24fc85f022d981 > -- > 2.53.0 >
