Resend becasue subject is incorrect.
LTO with MODVERSIONS 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 >> [email protected]))
The issue is fixed when make version upgrading to 4.2.
Thus we need to check make version during selecting on LTO Kconfig.
Add CONFIG_MAKE_VERSION which means MAKE_VERSION in canonical digits
for arithmetic comparisons.
[1] https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Lecopzer Chen <[email protected]>
----
v2:
- change MAKE_VERSION_INT to MAKE_VERSION
- remove $(make-version)
- tweak commit message
v1:
https://lore.kernel.org/lkml/[email protected]/
----
Lecopzer Chen (2):
Kbuild: lto: add CONFIG_MAKE_VERSION
Kbuild: lto: add make version checking
Makefile | 2 +-
arch/Kconfig | 1 +
init/Kconfig | 4 ++++
scripts/make-version.sh | 13 +++++++++++++
4 files changed, 19 insertions(+), 1 deletion(-)
create mode 100755 scripts/make-version.sh
--
2.18.0
LTO with MODVERSIONS will fail in generating correct CRC because
the makefile rule doesn't work for make with version 3.8X.[1]
Thus we need to check make version during selecting on LTO Kconfig.
and the suitable version should be 4.2(40200) which released in 2016[2].
[1] https://lore.kernel.org/lkml/[email protected]/
[2] https://ftp.gnu.org/gnu/make/
Signed-off-by: Lecopzer Chen <[email protected]>
---
arch/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/Kconfig b/arch/Kconfig
index 129df498a8e1..beee68149da8 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -639,6 +639,7 @@ config HAS_LTO_CLANG
def_bool y
# Clang >= 11: https://github.com/ClangBuiltLinux/linux/issues/510
depends on CC_IS_CLANG && CLANG_VERSION >= 110000 && LD_IS_LLD && AS_IS_LLVM
+ depends on !MODVERSIONS || MAKE_VERSION >= 40200
depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
depends on ARCH_SUPPORTS_LTO_CLANG
--
2.18.0