On Sun, 12 Apr 2015 17:54:27 -0700 Andi Kleen <andi@xxxxxxxxxxxxxx> wrote: > From: Andi Kleen <ak@xxxxxxxxxxxxxxx> > > gcc 5 supports a new -mcount-record option to generate ftrace > tables directly. This avoids the need to run record_mcount > manually. > > Use this option when available. > > It also has a -mcount-nop option to generate the mcount calls > as nops. So far that is not implemented, but it could be used > to optimize patching at boot up. Interesting. But I can't accept this until I can test it. I don't have the time to build gcc from scratch, and currently none of my boxes have a gcc 5 install. I wonder who's responsible for https://www.kernel.org/pub/tools/crosstool/files/bin/x86_64/ If they can add a i386/x86_64 build for gcc5 I'll be happy to download it and test this patch. Thanks, -- Steve > > Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx> > --- > scripts/Makefile.build | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index 01df30a..f258e9b 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -210,6 +210,11 @@ cmd_modversions = \ > fi; > endif > > +# gcc 5 supports generating the mcount tables directly > +ifneq ($(call cc-option,-mrecord-mcount,y),y) > +KBUILD_CFLAGS += -mrecord-mcount > +else > +# else do it all manually > ifdef CONFIG_FTRACE_MCOUNT_RECORD > ifdef BUILD_C_RECORDMCOUNT > ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") > @@ -240,6 +245,7 @@ cmd_record_mcount = \ > $(sub_cmd_record_mcount) \ > fi; > endif > +endif > > define rule_cc_o_c > $(call echo-cmd,checksrc) $(cmd_checksrc) \ -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
