Support creation of module BTF along with distilled base BTF; the latter is stored in a .BTF.base ELF section and supplements split BTF references to base BTF with information about base types, allowing for later relocation of split BTF with a (possibly changed) base. resolve_btfids uses the "-B" option to specify that the BTF.ids section should be populated with split BTF relative to the added .BTF.base section rather than relative to the vmlinux base. Modules will be built with a distilled .BTF.base section for external module build, i.e. make -C. -M=path2/module ...while in-tree module build as part of a normal kernel build will not generate distilled base BTF; this is because in-tree modules change with the kernel and do not require BTF relocation for the running vmlinux. Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx> --- scripts/Makefile.btf | 7 +++++++ scripts/Makefile.modfinal | 4 ++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/scripts/Makefile.btf b/scripts/Makefile.btf index 8e6a9d4b492e..8a3f45813c1e 100644 --- a/scripts/Makefile.btf +++ b/scripts/Makefile.btf @@ -19,4 +19,11 @@ pahole-flags-$(call test-ge, $(pahole-ver), 126) = -j --btf_features=encode_forc pahole-flags-$(CONFIG_PAHOLE_HAS_LANG_EXCLUDE) += --lang_exclude=rust +ifneq ($(KBUILD_EXTMOD),) +module-pahole-flags-$(call test-ge, $(pahole-ver), 126) += --btf_features=distilled_base +module-resolve-btfids-flags-$(call test-ge, $(pahole-ver), 126) = -B +endif + export PAHOLE_FLAGS := $(pahole-flags-y) +export MODULE_PAHOLE_FLAGS := $(module-pahole-flags-y) +export MODULE_RESOLVE_BTFIDS_FLAGS := $(module-resolve-btfids-flags-y) diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal index 8568d256d6fb..22f5bb0a60a6 100644 --- a/scripts/Makefile.modfinal +++ b/scripts/Makefile.modfinal @@ -39,8 +39,8 @@ quiet_cmd_btf_ko = BTF [M] $@ if [ ! -f vmlinux ]; then \ printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \ else \ - LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_base vmlinux $@; \ - $(RESOLVE_BTFIDS) -b vmlinux $@; \ + LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) $(MODULE_PAHOLE_FLAGS) --btf_base vmlinux $@; \ + $(RESOLVE_BTFIDS) $(MODULE_RESOLVE_BTFIDS_FLAGS) -b vmlinux $@; \ fi; # Same as newer-prereqs, but allows to exclude specified extra dependencies -- 2.31.1
