[PATCH v4 06/17] kbuild: add stamp file for vmlinux BTF data
From: Thomas Weißschuh <linux@weissschuh.net>
Date: 2026-01-13 12:37:51
Also in:
linux-arch, linux-doc, linux-integrity, linux-kbuild, linux-modules, linux-security-module, lkml
Subsystem:
kernel build + files below scripts/ (unless maintained elsewhere), the rest · Maintainers:
Nathan Chancellor, Nicolas Schier, Linus Torvalds
The upcoming module hashes functionality will build the modules in between the generation of the BTF data and the final link of vmlinux. Having a dependency from the modules on vmlinux would make this impossible as it would mean having a cyclic dependency. Break this cyclic dependency by introducing a new target. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- scripts/Makefile.modfinal | 4 ++-- scripts/link-vmlinux.sh | 6 ++++++ 2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 149e12ff5700..adfef1e002a9 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal@@ -56,8 +56,8 @@ if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \ printf '%s\n' 'savedcmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:) # Re-generate module BTFs if either module's .ko or vmlinux changed -%.ko: %.o %.mod.o .module-common.o $(objtree)/scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),$(objtree)/vmlinux) FORCE - +$(call if_changed_except,ld_ko_o,$(objtree)/vmlinux) +%.ko: %.o %.mod.o .module-common.o $(objtree)/scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),$(objtree)/.tmp_vmlinux_btf.stamp) FORCE + +$(call if_changed_except,ld_ko_o,$(objtree)/.tmp_vmlinux_btf.stamp) ifdef CONFIG_DEBUG_INFO_BTF_MODULES +$(if $(newer-prereqs),$(call cmd,btf_ko)) endif
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 4ab44c73da4d..8c98f8645a5c 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh@@ -111,6 +111,7 @@ vmlinux_link() gen_btf() { local btf_data=${1}.btf.o + local btf_stamp=.tmp_vmlinux_btf.stamp info BTF "${btf_data}" LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
@@ -131,6 +132,11 @@ gen_btf() fi printf "${et_rel}" | dd of="${btf_data}" conv=notrunc bs=1 seek=16 status=none + info STAMP $btf_stamp + if ! cmp --silent $btf_data $btf_stamp; then + cp $btf_data $btf_stamp + fi + btf_vmlinux_bin_o=${btf_data} }
--
2.52.0