Reproducible builds [1] require that the same source code with
the same set of tools can build identical objects each time,
but pahole in parallel mode was non-deterministic in
BTF generation prior to
dba7b5e ("pahole: Encode BTF serially in a reproducible build")
This was a problem since said BTF is baked into kernels and modules in
.BTF sections, so parallel pahole was causing non-reproducible binary
generation. Now with the above commit we have support for parallel
reproducible BTF generation in pahole.
KBUILD_BUILD_TIMESTAMP is set for reproducible builds, so if it
is set, add reproducible_build to --btf_features.
[1] Documentation/kbuild/reproducible-builds.rst
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
scripts/Makefile.btf | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/scripts/Makefile.btf b/scripts/Makefile.btf
index b75f09f3f424..40bb72662967 100644
--- a/scripts/Makefile.btf
+++ b/scripts/Makefile.btf
@@ -21,6 +21,10 @@ else
# Switch to using --btf_features for v1.26 and later.
pahole-flags-$(call test-ge, $(pahole-ver), 126) = -j --btf_features=encode_force,var,float,enum64,decl_tag,type_tag,optimized_func,consistent_func,decl_tag_kfuncs
+ifneq ($(KBUILD_BUILD_TIMESTAMP),)
+pahole-flags-$(call test-ge, $(pahole-ver), 126) += --btf_features=reproducible_build
+endif
+
ifneq ($(KBUILD_EXTMOD),)
module-pahole-flags-$(call test-ge, $(pahole-ver), 126) += --btf_features=distilled_base
endif
--
2.31.1
