By having a BTF_BASE variable defaulting to using vmlinux
as base BTF, we allow module builders to build standalone
BTF such that it is generated independently and not
de-duplicated with core vmlinux BTF. This allows such
modules to be more resilient to changes in vmlinux BTF
if they occur, as would happen if a change resulted in
a different vmlinux BTF id mapping.
Opt-out of split BTF is done via
make BTF_BASE= M=path/2/module
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
scripts/Makefile.modfinal | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index b3a6aa8fbe8c..b69fd46b040a 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -30,6 +30,8 @@ quiet_cmd_cc_o_c = CC [M] $@
ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
+BTF_BASE := --btf_base vmlinux
+
quiet_cmd_ld_ko_o = LD [M] $@
cmd_ld_ko_o += \
$(LD) -r $(KBUILD_LDFLAGS) \
@@ -42,8 +44,8 @@ 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) $(BTF_BASE) $@; \
+ $(RESOLVE_BTFIDS) $(BTF_BASE) $@; \
fi;
# Same as newer-prereqs, but allows to exclude specified extra dependencies
--
2.31.1
