kbuild: refactor cmd_modversions_c

cmd_modversions_c implements two parts; run genksyms to calculate CRCs
of exported symbols, run $(LD) to update the object with the CRCs. The
latter is not executed for CONFIG_LTO_CLANG=y since the object is not
ELF but LLVM bit code at this point.

The first part can be unified because we can always use $(NM) instead
of "$(OBJDUMP) -h" to dump the symbols.

Split the code into the two macros, cmd_gen_symversions_c and
cmd_modversions.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
This commit is contained in:
Masahiro Yamada 2022-04-05 20:33:57 +09:00
parent 79f646e865
commit 8017ce5064

View File

@ -168,28 +168,24 @@ ifdef CONFIG_MODVERSIONS
# the actual value of the checksum generated by genksyms
# o remove .tmp_<file>.o to <file>.o
ifdef CONFIG_LTO_CLANG
# Generate .o.symversions files for each .o with exported symbols, and link these
# to the kernel and/or modules at the end.
cmd_modversions_c = \
gen_symversions = \
if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \
$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
$(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
> $@.symversions; \
else \
rm -f $@.symversions; \
fi;
else
cmd_modversions_c = \
if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
> $(@D)/.tmp_$(@F:.o=.ver); \
\
$(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
-T $(@D)/.tmp_$(@F:.o=.ver); \
mv -f $(@D)/.tmp_$(@F) $@; \
rm -f $(@D)/.tmp_$(@F:.o=.ver); \
fi
endif
cmd_gen_symversions_c = $(call gen_symversions,c)
cmd_modversions = \
if [ -r $@.symversions ]; then \
$(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
-T $@.symversions; \
mv -f $(@D)/.tmp_$(@F) $@; \
fi
endif
ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
@ -271,7 +267,8 @@ define rule_cc_o_c
$(call cmd,checksrc)
$(call cmd,checkdoc)
$(call cmd,gen_objtooldep)
$(call cmd,modversions_c)
$(call cmd,gen_symversions_c)
$(if $(CONFIG_LTO_CLANG),,$(call cmd,modversions))
$(call cmd,record_mcount)
endef