Commit d31ed5d7 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

kbuild: Fixup the IBT kbuild changes 



Masahiro-san deemed my kbuild changes to support whole module objtool
runs too terrible to live and gracefully provided an alternative.

Suggested-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/CAK7LNAQ2mYMnOKMQheVi+6byUFE3KEkjm1zcndNUfe0tORGvug@mail.gmail.com
parent 9cea0d46

scripts/Makefile.build

+19 −47
Original line number Original line Diff line number Diff line
@@ -86,18 +86,12 @@ ifdef need-builtin 
targets-for-builtin += $(obj)/built-in.a

targets-for-builtin += $(obj)/built-in.a

endif

endif





targets-for-modules :=

targets-for-modules := $(patsubst %.o, %.mod, $(filter %.o, $(obj-m)))





ifdef CONFIG_LTO_CLANG

ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),)

targets-for-modules += $(patsubst %.o, %.lto.o, $(filter %.o, $(obj-m)))

targets-for-modules += $(patsubst %.o, %.prelink.o, $(filter %.o, $(obj-m)))

endif



ifdef CONFIG_X86_KERNEL_IBT

targets-for-modules += $(patsubst %.o, %.objtool, $(filter %.o, $(obj-m)))

endif

endif





targets-for-modules += $(patsubst %.o, %.mod, $(filter %.o, $(obj-m)))



ifdef need-modorder

ifdef need-modorder

targets-for-modules += $(obj)/modules.order

targets-for-modules += $(obj)/modules.order

endif

endif
@@ -244,31 +238,16 @@ objtool_args = \ 
	$(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount)		\

	$(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount)		\

	$(if $(CONFIG_SLS), --sls)

	$(if $(CONFIG_SLS), --sls)





cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $(@:.objtool=.o))

cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@)

cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$(@:.objtool=.o): $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)

cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)





endif # CONFIG_STACK_VALIDATION

endif # CONFIG_STACK_VALIDATION





ifdef CONFIG_LTO_CLANG

ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),)





# Skip objtool for LLVM bitcode

# Skip objtool for LLVM bitcode

$(obj)/%.o: objtool-enabled :=

$(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 ifdef CONFIG_X86_KERNEL_IBT



# Skip objtool on individual files

$(obj)/%.o: objtool-enabled :=



# instead run objtool on the module as a whole, right before

# the final link pass with the linker script.

$(obj)/%.objtool: objtool-enabled = y

$(obj)/%.objtool: part-of-module := y



else

else





# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory

# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
@@ -310,19 +289,24 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE 
	$(call if_changed_rule,cc_o_c)

	$(call if_changed_rule,cc_o_c)

	$(call cmd,force_checksrc)

	$(call cmd,force_checksrc)





ifdef CONFIG_LTO_CLANG

ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),)

# Module .o files may contain LLVM bitcode, compile them into native code

# Module .o files may contain LLVM bitcode, compile them into native code

# before ELF processing

# before ELF processing

quiet_cmd_cc_lto_link_modules = LTO [M] $@

quiet_cmd_cc_prelink_modules = LD [M]  $@

      cmd_cc_lto_link_modules =						\

      cmd_cc_prelink_modules =						\

	$(LD) $(ld_flags) -r -o $@					\

	$(LD) $(ld_flags) -r -o $@					\

		$(shell [ -s $(@:.lto.o=.o.symversions) ] &&		\

               $(shell [ -s $(@:.prelink.o=.o.symversions) ] &&		\

			echo -T $(@:.lto.o=.o.symversions))		\

                       echo -T $(@:.prelink.o=.o.symversions))		\

		--whole-archive $(filter-out FORCE,$^)			\

		--whole-archive $(filter-out FORCE,$^)			\

		$(cmd_objtool)

		$(cmd_objtool)





$(obj)/%.lto.o: $(obj)/%.o FORCE

# objtool was skipped for LLVM bitcode, run it now that we have compiled

	$(call if_changed,cc_lto_link_modules)

# modules into native code

$(obj)/%.prelink.o: objtool-enabled = y

$(obj)/%.prelink.o: part-of-module := y



$(obj)/%.prelink.o: $(obj)/%.o FORCE

	$(call if_changed,cc_prelink_modules)

endif

endif





cmd_mod = { \

cmd_mod = { \
@@ -333,18 +317,6 @@ cmd_mod = { \ 
$(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE

$(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE

	$(call if_changed,mod)

	$(call if_changed,mod)





#

# Since objtool will re-write the file it will change the timestamps, therefore

# it is critical that the %.objtool file gets a timestamp *after* objtool runs.

#

# Additionally, care must be had with ordering this rule against the other rules

# that take %.o as a dependency.

#

cmd_objtool_mod = true $(cmd_objtool) ; touch $@



$(obj)/%.objtool: $(obj)/%$(mod-prelink-ext).o FORCE

	$(call if_changed,objtool_mod)



quiet_cmd_cc_lst_c = MKLST   $@

quiet_cmd_cc_lst_c = MKLST   $@

      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \

      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \

		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \

		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
@@ -498,7 +470,7 @@ $(obj)/lib.a: $(lib-y) FORCE 
# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object

# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object

# module is turned into a multi object module, $^ will contain header file

# module is turned into a multi object module, $^ will contain header file

# dependencies recorded in the .*.cmd file.

# dependencies recorded in the .*.cmd file.

ifdef CONFIG_LTO_CLANG

ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),)

quiet_cmd_link_multi-m = AR [M]  $@

quiet_cmd_link_multi-m = AR [M]  $@

cmd_link_multi-m =						\

cmd_link_multi-m =						\

	$(cmd_update_lto_symversions);				\

	$(cmd_update_lto_symversions);				\

scripts/Makefile.lib

+2 −2
Original line number Original line Diff line number Diff line
@@ -230,11 +230,11 @@ dtc_cpp_flags = -Wp,-MMD,$(depfile).pre.tmp -nostdinc \ 
		 $(addprefix -I,$(DTC_INCLUDE))                          \

		 $(addprefix -I,$(DTC_INCLUDE))                          \

		 -undef -D__DTS__

		 -undef -D__DTS__





ifeq ($(CONFIG_LTO_CLANG),y)

ifneq ($(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT),)

# With CONFIG_LTO_CLANG, .o files in modules might be LLVM bitcode, so we

# With CONFIG_LTO_CLANG, .o files in modules might be LLVM bitcode, so we

# need to run LTO to compile them into native code (.lto.o) before further

# need to run LTO to compile them into native code (.lto.o) before further

# processing.

# processing.

mod-prelink-ext := .lto

mod-prelink-ext := .prelink

endif

endif





# Useful for describing the dependency of composite objects

# Useful for describing the dependency of composite objects

scripts/mod/modpost.c

+6 −6
Original line number Original line Diff line number Diff line
@@ -1989,9 +1989,9 @@ static char *remove_dot(char *s) 
		if (m && (s[n + m] == '.' || s[n + m] == 0))

		if (m && (s[n + m] == '.' || s[n + m] == 0))

			s[n] = 0;

			s[n] = 0;





		/* strip trailing .lto */

		/* strip trailing .prelink */

		if (strends(s, ".lto"))

		if (strends(s, ".prelink"))

			s[strlen(s) - 4] = '\0';

			s[strlen(s) - 8] = '\0';

	}

	}

	return s;

	return s;

}

}
@@ -2015,9 +2015,9 @@ static void read_symbols(const char *modname) 
		/* strip trailing .o */

		/* strip trailing .o */

		tmp = NOFAIL(strdup(modname));

		tmp = NOFAIL(strdup(modname));

		tmp[strlen(tmp) - 2] = '\0';

		tmp[strlen(tmp) - 2] = '\0';

		/* strip trailing .lto */

		/* strip trailing .prelink */

		if (strends(tmp, ".lto"))

		if (strends(tmp, ".prelink"))

			tmp[strlen(tmp) - 4] = '\0';

			tmp[strlen(tmp) - 8] = '\0';

		mod = new_module(tmp);

		mod = new_module(tmp);

		free(tmp);

		free(tmp);

	}

	}