diff options
| author | Nicolas Pitre <nicolas.pitre@linaro.org> | 2016-01-21 23:07:24 +0100 |
|---|---|---|
| committer | Nicolas Pitre <nicolas.pitre@linaro.org> | 2016-03-29 19:30:54 +0200 |
| commit | 9895c03d48115c7783c0ef0a591447d53254ef84 (patch) | |
| tree | 6cd59c256bb47b9b2befdddde3322e010b91359c | |
| parent | Linux 4.6-rc1 (diff) | |
| download | linux-9895c03d48115c7783c0ef0a591447d53254ef84.tar.xz linux-9895c03d48115c7783c0ef0a591447d53254ef84.zip | |
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 <nico@linaro.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
| -rw-r--r-- | scripts/Makefile.build | 13 |
1 files changed, 11 insertions, 2 deletions
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) |