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| author | Sami Tolvanen <samitolvanen@google.com> | 2020-04-14 02:10:13 +0300 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2021-02-23 23:46:57 +0300 |
| commit | b1a1a1a09b4606d41723a426110382d2077c26fb (patch) | |
| tree | 4c6672f8aa90443585f2ceb4cb4e65425d800c6a /scripts/Makefile.modfinal | |
| parent | 41425ebe20245c99b44d6ba0f017be9bfc28414f (diff) | |
| download | linux-b1a1a1a09b4606d41723a426110382d2077c26fb.tar.xz | |
kbuild: lto: postpone objtool
With LTO, LLVM bitcode won't be compiled into native code until
modpost_link, or modfinal for modules. This change postpones calls
to objtool until after these steps, and moves objtool_args to
Makefile.lib, so the arguments can be reused in Makefile.modfinal.
As we didn't have objects to process earlier, we use --duplicate
when processing vmlinux.o. This change also disables unreachable
instruction warnings with LTO to avoid warnings about the int3
padding between functions.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'scripts/Makefile.modfinal')
| -rw-r--r-- | scripts/Makefile.modfinal | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal index 6de2c35b64e8..735e11e9041b 100644 --- a/scripts/Makefile.modfinal +++ b/scripts/Makefile.modfinal @@ -9,7 +9,7 @@ __modfinal: include include/config/auto.conf include $(srctree)/scripts/Kbuild.include -# for c_flags +# for c_flags and objtool_args include $(srctree)/scripts/Makefile.lib # find all modules listed in modules.order @@ -34,10 +34,23 @@ ifdef CONFIG_LTO_CLANG # With CONFIG_LTO_CLANG, reuse the object file we compiled for modpost to # avoid a second slow LTO link prelink-ext := .lto -endif + +# ELF processing was skipped earlier because we didn't have native code, +# so let's now process the prelinked binary before we link the module. + +ifdef CONFIG_STACK_VALIDATION +ifneq ($(SKIP_STACK_VALIDATION),1) +cmd_ld_ko_o += \ + $(objtree)/tools/objtool/objtool $(objtool_args) \ + $(@:.ko=$(prelink-ext).o); + +endif # SKIP_STACK_VALIDATION +endif # CONFIG_STACK_VALIDATION + +endif # CONFIG_LTO_CLANG quiet_cmd_ld_ko_o = LD [M] $@ - cmd_ld_ko_o = \ + cmd_ld_ko_o += \ $(LD) -r $(KBUILD_LDFLAGS) \ $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \ -T scripts/module.lds -o $@ $(filter %.o, $^); \ |