Re: [PATCH v2 06/13] kbuild: reuse $(cmd_objtool) for cmd_cc_lto_link_modules
From: Kees Cook <hidden>
Date: 2021-08-31 17:35:34
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lkml
On Tue, Aug 31, 2021 at 04:39:57PM +0900, Masahiro Yamada wrote:
quoted hunk ↗ jump to hunk
For CONFIG_LTO_CLANG=y, the objtool processing is not possible at the compilation, hence postponed by the link time. Reuse $(cmd_objtool) for CONFIG_LTO_CLANG=y by defining objtool-enabled properly. For CONFIG_LTO_CLANG=y: objtool-enabled is off for %.o compilation objtool-enabled is on for %.lto link For CONFIG_LTO_CLANG=n: objtool-enabled is on for %.o compilation (but, it depends on OBJECT_FILE_NON_STANDARD) Set part-of-module := y for %.lto.o to avoid repeating --module. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- scripts/Makefile.build | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-)diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 21b55f37a23f..afc906cd7256 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build@@ -236,20 +236,26 @@ objtool_args = \ $(if $(CONFIG_X86_SMAP), --uaccess) \ $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) -ifndef CONFIG_LTO_CLANG +cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@) +cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd) + +endif # CONFIG_STACK_VALIDATION + +ifdef CONFIG_LTO_CLANG + +# Skip objtool for LLVM bitcode +$(obj)/%o: objtool-enabled :=
Is this intentionally "%o" instead of "%.o"? (And it later overridden by the "%.lto.o" rule?
quoted hunk ↗ jump to hunk
+ +else # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file -objtool-enabled = $(if $(filter-out y%, \ +$(obj)/%o: objtool-enabled = $(if $(filter-out y%, \ $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y) -cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@) -cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd) - -endif # CONFIG_LTO_CLANG -endif # CONFIG_STACK_VALIDATION +endif ifdef CONFIG_TRIM_UNUSED_KSYMS cmd_gen_ksymdeps = \@@ -289,13 +295,13 @@ cmd_cc_lto_link_modules = \ $(LD) $(ld_flags) -r -o $@ \ $(shell [ -s $(@:.lto.o=.o.symversions) ] && \ echo -T $(@:.lto.o=.o.symversions)) \ - --whole-archive $(filter-out FORCE,$^) + --whole-archive $(filter-out FORCE,$^) \ + $(cmd_objtool) -ifdef CONFIG_STACK_VALIDATION # objtool was skipped for LLVM bitcode, run it now that we have compiled # modules into native code -cmd_cc_lto_link_modules += ; $(objtool) $(objtool_args) --module $@ -endif +$(obj)/%.lto.o: objtool-enabled = y +$(obj)/%.lto.o: part-of-module := y $(obj)/%.lto.o: $(obj)/%.o FORCE $(call if_changed,cc_lto_link_modules)-- 2.30.2
-- Kees Cook