[PATCH v3 32/39] Kbuild: Allow whole module objtool runs

Peter Zijlstra
2022-03-03T11:34:03Z

Just like we have vmlinux.o objtool runs, add the ability to do whole
module objtool runs.

Suggested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
scripts/Makefile.build | 44 ++------------------------------------------
scripts/Makefile.lib | 45 +++++++++++++++++++++++++++++++++++++++++++++
scripts/Makefile.modfinal | 1 +
3 files changed, 48 insertions(+), 42 deletions(-)

--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -223,41 +223,6 @@ cmd_record_mcount = $(if $(findstring $(
$(sub_cmd_record_mcount))
endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT

-ifdef CONFIG_STACK_VALIDATION
-
-objtool := $(objtree)/tools/objtool/objtool
-
-objtool_args = \
- $(if $(CONFIG_UNWINDER_ORC),orc generate,check) \
- $(if $(part-of-module), --module) \
- $(if $(CONFIG_FRAME_POINTER),, --no-fp) \
- $(if $(CONFIG_GCOV_KERNEL)$(CONFIG_LTO_CLANG), --no-unreachable)\
- $(if $(CONFIG_RETPOLINE), --retpoline) \
- $(if $(CONFIG_X86_SMAP), --uaccess) \
- $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
- $(if $(CONFIG_SLS), --sls)
-
-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 :=
-
-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
-
-$(obj)/%.o: objtool-enabled = $(if $(filter-out y%, \
- $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y)
-
-endif
-
ifdef CONFIG_TRIM_UNUSED_KSYMS
cmd_gen_ksymdeps = \
$(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
@@ -292,21 +257,16 @@ ifdef CONFIG_LTO_CLANG
# Module .o files may contain LLVM bitcode, compile them into native code
# before ELF processing
quiet_cmd_cc_lto_link_modules = LTO [M] $@
-cmd_cc_lto_link_modules = \
+ cmd_cc_lto_link_modules = \
$(LD) $(ld_flags) -r -o $@ \
$(shell [ -s $(@:.lto.o=.o.symversions) ] && \
echo -T $(@:.lto.o=.o.symversions)) \
--whole-archive $(filter-out FORCE,$^) \
$(cmd_objtool)
-
-# objtool was skipped for LLVM bitcode, run it now that we have compiled
-# modules into native code
-$(obj)/%.lto.o: objtool-enabled = y
-$(obj)/%.lto.o: part-of-module := y
+endif

$(obj)/%.lto.o: $(obj)/%.o FORCE
$(call if_changed,cc_lto_link_modules)
-endif

cmd_mod = { \
echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -533,3 +533,48 @@ define filechk_offsets
echo ""; \
echo "#endif"
endef
+
+# objtool
+# ---------------------------------------------------------------------------
+
+ifdef CONFIG_STACK_VALIDATION
+
+objtool := $(objtree)/tools/objtool/objtool
+
+objtool_args = \
+ $(if $(CONFIG_UNWINDER_ORC),orc generate,check) \
+ $(if $(part-of-module), --module) \
+ $(if $(CONFIG_FRAME_POINTER),, --no-fp) \
+ $(if $(CONFIG_GCOV_KERNEL)$(CONFIG_LTO_CLANG), --no-unreachable)\
+ $(if $(CONFIG_RETPOLINE), --retpoline) \
+ $(if $(CONFIG_X86_SMAP), --uaccess) \
+ $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \
+ $(if $(CONFIG_SLS), --sls)
+
+cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@)
+cmd_objtool_mod = $(if $(objtool-enabled), $(objtool) $(objtool_args) $(@:.ko=.o) ; )
+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 :=
+
+# objtool was skipped for LLVM bitcode, run it now that we have compiled
+# modules into native code
+$(obj)/%.lto.o: objtool-enabled = y
+$(obj)/%.lto.o: part-of-module := y
+
+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
+
+$(obj)/%.o: objtool-enabled = $(if $(filter-out y%, \
+ $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y)
+
+endif
+
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -32,6 +32,7 @@ ARCH_POSTLINK := $(wildcard $(srctree)/a

quiet_cmd_ld_ko_o = LD [M] $@
cmd_ld_ko_o += \
+ $(cmd_objtool_mod) \
$(LD) -r $(KBUILD_LDFLAGS) \
$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
-T scripts/module.lds -o $@ $(filter %.o, $^); \