LTO with MODVERSION will fail in generating correct CRC because the makefile rule doesn't work for make with version 3.8X. Refer to [1]: > When building modules(CONFIG_...=m), I found some of module versions > are incorrect and set to 0. > This can be found in build log for first clean build which shows > WARNING: EXPORT symbol "XXXX" [drivers/XXX/XXX.ko] version generation failed, > symbol will not be versioned. > But in second build(incremental build), the WARNING disappeared and the > module version becomes valid CRC and make someone who want to change > modules without updating kernel image can't insert their modules. > The problematic code is > + $(foreach n, $(filter-out FORCE,$^), \ > + $(if $(wildcard $(n).symversions), \ > + ; cat $(n).symversions >> $@.symversions)) The issue fixed when make version upgrading to 4.2. Thus we need to check make version during selecting on LTO Kconfig. The MAKE_VERSION_INT means MAKE_VERSION in canonical digits integer and implemnted by imitating CLANG_VERSION. [1] https://lore.kernel.org/lkml/20210616080252.32046-1-lecopzer.chen@xxxxxxxxxxxx/ Signed-off-by: Lecopzer Chen <lecopzer.chen@xxxxxxxxxxxx> Lecopzer Chen (2): Kbuild: lto: add make-version macros Kbuild: lto: add make version checking Makefile | 2 +- arch/Kconfig | 1 + init/Kconfig | 4 ++++ scripts/Kconfig.include | 3 +++ scripts/make-version.sh | 13 +++++++++++++ 5 files changed, 22 insertions(+), 1 deletion(-) create mode 100755 scripts/make-version.sh -- 2.18.0
