| Message ID | 1454963315-20468-2-git-send-email-nicolas.pitre@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> > +# List module undefined symbols > +ifdef CONFIG_TRIM_UNUSED_EXPSYMS > +cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U \(.*\)/\1/p' | xargs echo > +else > +cmd_undef_syms = echo > +endif Use ":" as a "do nothing" cammand. Then you do not emit an empty line. Sam -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, 8 Feb 2016, Sam Ravnborg wrote: > > > > +# List module undefined symbols > > +ifdef CONFIG_TRIM_UNUSED_EXPSYMS > > +cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U \(.*\)/\1/p' | xargs echo > > +else > > +cmd_undef_syms = echo > > +endif > Use ":" as a "do nothing" cammand. Then you do not emit an empty line. I wanted to emit that empty line though. This way it is less likely that it'll be reused for other purposes. Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Feb 08, 2016 at 03:28:30PM -0500, Nicolas Pitre wrote: > +ifdef CONFIG_TRIM_UNUSED_EXPSYMS > +cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U \(.*\)/\1/p' | xargs echo Umm... sed -nre 's/^ +U //p', perhaps? -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 9 Feb 2016, Al Viro wrote: > On Mon, Feb 08, 2016 at 03:28:30PM -0500, Nicolas Pitre wrote: > > +ifdef CONFIG_TRIM_UNUSED_EXPSYMS > > +cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U \(.*\)/\1/p' | xargs echo > > Umm... sed -nre 's/^ +U //p', perhaps? Yep, I like it better. Although I might be tempted by sed -n 's/^ \+U //p' to avoid the "non portable" mention that comes with -r (do we actually care?). Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 2c47f9c305..1d8b07ea3e 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -253,6 +253,13 @@ define rule_cc_o_c mv -f $(dot-target).tmp $(dot-target).cmd endef +# List module undefined symbols +ifdef CONFIG_TRIM_UNUSED_EXPSYMS +cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U \(.*\)/\1/p' | xargs echo +else +cmd_undef_syms = echo +endif + # Built-in and composite module parts $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(call cmd,force_checksrc) @@ -263,7 +270,8 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) 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 $< && \ @@ -393,7 +401,8 @@ $(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)
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_EXPSYMS is selected. Signed-off-by: Nicolas Pitre <nico@linaro.org> --- scripts/Makefile.build | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)