From 9895c03d48115c7783c0ef0a591447d53254ef84 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Thu, 21 Jan 2016 17:07:24 -0500 Subject: kbuild: record needed exported symbols for modules Kernel modules are partially linked object files with some undefined symbols that are expected to be matched with EXPORT_SYMBOL() entries from elsewhere. Each .tmp_versions/*.mod file currently contains two line of text separated by a newline character. The first line has the actual module file name while the second line has a list of object files constituting that module. Those files are parsed by modpost (scripts/mod/sumversion.c), scripts/Makefile.modpost, scripts/Makefile.modsign, etc. Only the modpost utility cares about the second line while the others retrieve only the first line. Therefore we can add a third line to record the list of undefined symbols aka required EXPORT_SYMBOL() entries for each module into that file without breaking anything. Like for the second line, symbols are separated by a blank and the list is terminated with a newline character. To avoid needless build overhead, the undefined symbols extraction is performed only when CONFIG_TRIM_UNUSED_KSYMS is selected. Signed-off-by: Nicolas Pitre Acked-by: Rusty Russell --- scripts/Makefile.build | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'scripts/Makefile.build') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index e1bc1907090e..74556e5e4ec0 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -286,6 +286,13 @@ define rule_as_o_S mv -f $(dot-target).tmp $(dot-target).cmd endef +# List module undefined symbols (or empty line if not enabled) +ifdef CONFIG_TRIM_UNUSED_KSYMS +cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo +else +cmd_undef_syms = echo +endif + # Built-in and composite module parts $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE $(call cmd,force_checksrc) @@ -296,7 +303,8 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE $(call cmd,force_checksrc) $(call if_changed_rule,cc_o_c) - @{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod) + @{ echo $(@:.o=.ko); echo $@; \ + $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod) quiet_cmd_cc_lst_c = MKLST $@ cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \ @@ -426,7 +434,8 @@ $(call multi_depend, $(multi-used-y), .o, -objs -y) $(multi-used-m): FORCE $(call if_changed,link_multi-m) - @{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod) + @{ echo $(@:.o=.ko); echo $(link_multi_deps); \ + $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod) $(call multi_depend, $(multi-used-m), .o, -objs -y -m) targets += $(multi-used-y) $(multi-used-m) -- cgit v1.2.3 From e4aca45950050fc584e036bb1b266ce1264a6daf Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Wed, 17 Feb 2016 15:50:06 -0500 Subject: kbuild: de-duplicate fixdep usage The generation and postprocessing of automatic dependency rules is duplicated in rule_cc_o_c, rule_as_o_S and if_changed_dep. Since this is not a trivial one-liner action, it is now abstracted under cmd_and_fixdep to simplify things and make future changes in this area easier. In the rule_cc_o_c and rule_as_o_S cases that means the order of some commands has been altered, namely fixdep and related file manipulations are executed earlier, but they didn't depend on those commands that now execute later. Signed-off-by: Nicolas Pitre --- scripts/Makefile.build | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) (limited to 'scripts/Makefile.build') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 74556e5e4ec0..12821d9eae85 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -266,24 +266,15 @@ endif # CONFIG_STACK_VALIDATION define rule_cc_o_c $(call echo-cmd,checksrc) $(cmd_checksrc) \ - $(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \ + $(call cmd_and_fixdep,cc_o_c) \ $(cmd_modversions) \ - $(cmd_objtool) \ - $(call echo-cmd,record_mcount) \ - $(cmd_record_mcount) \ - scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \ - $(dot-target).tmp; \ - rm -f $(depfile); \ - mv -f $(dot-target).tmp $(dot-target).cmd + $(cmd_objtool) \ + $(call echo-cmd,record_mcount) $(cmd_record_mcount) endef define rule_as_o_S - $(call echo-cmd,as_o_S) $(cmd_as_o_S); \ - $(cmd_objtool) \ - scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,as_o_S)' > \ - $(dot-target).tmp; \ - rm -f $(depfile); \ - mv -f $(dot-target).tmp $(dot-target).cmd + $(call cmd_and_fixdep,as_o_S) \ + $(cmd_objtool) endef # List module undefined symbols (or empty line if not enabled) -- cgit v1.2.3 From 23d43848708afd7aa9a2c8516a3f269a3e71be4f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 8 Apr 2016 11:24:47 +0900 Subject: kbuild: rename cmd_cc_i_c to cmd_cpp_i_c This command just preprocesses .c files into .i files, so cmd_cpp_i_c seems more suitable. Signed-off-by: Masahiro Yamada Acked-by: Arnaldo Carvalho de Melo Signed-off-by: Michal Marek --- scripts/Makefile.build | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'scripts/Makefile.build') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 12821d9eae85..13f606ba2a3b 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -152,11 +152,11 @@ cmd_cc_s_c = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $< $(obj)/%.s: $(src)/%.c FORCE $(call if_changed_dep,cc_s_c) -quiet_cmd_cc_i_c = CPP $(quiet_modtag) $@ -cmd_cc_i_c = $(CPP) $(c_flags) -o $@ $< +quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@ +cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< $(obj)/%.i: $(src)/%.c FORCE - $(call if_changed_dep,cc_i_c) + $(call if_changed_dep,cpp_i_c) cmd_gensymtypes = \ $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ -- cgit v1.2.3 From e0f41e52ddf5dc676577f974c9f0af77732f251a Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 8 Apr 2016 11:24:48 +0900 Subject: kbuild: rename cmd_as_s_S to cmd_cpp_s_S This command just preprocesses .S files into .s files, so cmd_cpp_s_S seems more suitable. Signed-off-by: Masahiro Yamada Signed-off-by: Michal Marek --- scripts/Makefile.build | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'scripts/Makefile.build') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 13f606ba2a3b..0d1ca5bf42fb 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -313,11 +313,11 @@ modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL) $(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) $(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) -quiet_cmd_as_s_S = CPP $(quiet_modtag) $@ -cmd_as_s_S = $(CPP) $(a_flags) -o $@ $< +quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ +cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< $(obj)/%.s: $(src)/%.S FORCE - $(call if_changed_dep,as_s_S) + $(call if_changed_dep,cpp_s_S) quiet_cmd_as_o_S = AS $(quiet_modtag) $@ cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< -- cgit v1.2.3