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| author | Masahiro Yamada <masahiroy@kernel.org> | 2025-01-31 17:04:01 +0300 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2025-01-31 22:28:05 +0300 |
| commit | 695ed93bb30e03e9f826ee70abdd83f970741a37 (patch) | |
| tree | 3ded5ccff06562c0f0414e8215c0185b238a067a /scripts/Makefile.lib | |
| parent | 71d815bf5dfd4f63f7557e0abe7f257c202863a1 (diff) | |
| download | linux-695ed93bb30e03e9f826ee70abdd83f970741a37.tar.xz | |
kbuild: fix Clang LTO with CONFIG_OBJTOOL=n
Since commit bede169618c6 ("kbuild: enable objtool for *.mod.o and
additional kernel objects"), Clang LTO builds do not perform any
optimizations when CONFIG_OBJTOOL is disabled (e.g., for ARCH=arm64).
This is because every LLVM bitcode file is immediately converted to
ELF format before the object files are linked together.
This commit fixes the breakage.
Fixes: bede169618c6 ("kbuild: enable objtool for *.mod.o and additional kernel objects")
Reported-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Yonghong Song <yonghong.song@linux.dev>
Diffstat (limited to 'scripts/Makefile.lib')
| -rw-r--r-- | scripts/Makefile.lib | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index f604f51d23ca..ad55ef201aac 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -287,6 +287,8 @@ delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT)) cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool-args) $@) cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd) +objtool-enabled := y + endif # CONFIG_OBJTOOL # Useful for describing the dependency of composite objects @@ -302,11 +304,11 @@ endef # =========================================================================== # These are shared by some Makefile.* files. -objtool-enabled := y - ifdef CONFIG_LTO_CLANG -# objtool cannot process LLVM IR. Make $(LD) covert LLVM IR to ELF here. -cmd_ld_single = $(if $(objtool-enabled), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@) +# Run $(LD) here to covert LLVM IR to ELF in the following cases: +# - when this object needs objtool processing, as objtool cannot process LLVM IR +# - when this is a single-object module, as modpost cannot process LLVM IR +cmd_ld_single = $(if $(objtool-enabled)$(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@) endif quiet_cmd_cc_o_c = CC $(quiet_modtag) $@ |