On Tue, Mar 5, 2019 at 11:46 PM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > > On Tue, Mar 05, 2019 at 02:48:16PM +0900, Masahiro Yamada wrote: > > Tools that are globally needed for building the kernel are supposed to > > be put in the scripts/ directory, but objtool is the exceptional one. > > > > People were confused by objtool's Makefile since most of tools run on > > the target whereas objtool runs on the host machine. Some time ago, > > Douglas Anderson suggested to move tools/objtool/ to scripts/tools/ > > (https://patchwork.kernel.org/patch/9983535/#20996057), but we did > > not go as far as submitting a patch at that time. > > > > Recently, Robin Meijboom reported that the generated files for objtool > > were never cleaned up. (https://patchwork.kernel.org/patch/10813797/) > > > > So, I looked into this to fix the distortion. Move tools/objtool/ to > > scripts/objtool/, and rewrite Makefiles in the Kbuild-ish manner. > > > > I also cleaned up the top-level Makefile by moving the libelf check > > scripts/objtool/Makefile. > > > > I see some benefits in this. > > > > [1] generated files under scripts/ are cleaned up by 'make mrproper' > > > > Currently, the generated files under tools/objtool/ are not cleaned up > > since the build system under tools/ is a complete different world. > > > > If we want to clean them up, it should be done by 'make mrproper' > > instead of 'make clean' since objtool is needed for building external > > modules. > > > > This commit naturally solves the issue since Kbuild cleans under > > scripts/ by 'make mrproper'. > > Yes, but this can be solved instead with a one-line patch. > > > [2] build log looks nicer > > > > Currently, the build log under tools/objtool/ shows absolute paths, and > > displays 'DESCEND objtool' every time for incremental building. > > > > Switching over to the standard Kbuild scheme will improve the log. > > > > Before: > > > > DESCEND objtool > > HOSTCC /home/masahiro/workspace/linux/tools/objtool/fixdep.o > > HOSTLD /home/masahiro/workspace/linux/tools/objtool/fixdep-in.o > > LINK /home/masahiro/workspace/linux/tools/objtool/fixdep > > CC /home/masahiro/workspace/linux/tools/objtool/exec-cmd.o > > CC /home/masahiro/workspace/linux/tools/objtool/help.o > > CC /home/masahiro/workspace/linux/tools/objtool/pager.o > > CC /home/masahiro/workspace/linux/tools/objtool/parse-options.o > > CC /home/masahiro/workspace/linux/tools/objtool/run-command.o > > CC /home/masahiro/workspace/linux/tools/objtool/sigchain.o > > CC /home/masahiro/workspace/linux/tools/objtool/subcmd-config.o > > LD /home/masahiro/workspace/linux/tools/objtool/libsubcmd-in.o > > AR /home/masahiro/workspace/linux/tools/objtool/libsubcmd.a > > GEN /home/masahiro/workspace/linux/tools/objtool/arch/x86/lib/inat-tables.c > > CC /home/masahiro/workspace/linux/tools/objtool/arch/x86/decode.o > > LD /home/masahiro/workspace/linux/tools/objtool/arch/x86/objtool-in.o > > CC /home/masahiro/workspace/linux/tools/objtool/builtin-check.o > > CC /home/masahiro/workspace/linux/tools/objtool/builtin-orc.o > > CC /home/masahiro/workspace/linux/tools/objtool/check.o > > CC /home/masahiro/workspace/linux/tools/objtool/orc_gen.o > > CC /home/masahiro/workspace/linux/tools/objtool/orc_dump.o > > CC /home/masahiro/workspace/linux/tools/objtool/elf.o > > CC /home/masahiro/workspace/linux/tools/objtool/special.o > > CC /home/masahiro/workspace/linux/tools/objtool/objtool.o > > CC /home/masahiro/workspace/linux/tools/objtool/libstring.o > > CC /home/masahiro/workspace/linux/tools/objtool/str_error_r.o > > LD /home/masahiro/workspace/linux/tools/objtool/objtool-in.o > > LINK /home/masahiro/workspace/linux/tools/objtool/objtool > > > > After: > > > > HOSTCC scripts/objtool/builtin-check.o > > HOSTCC scripts/objtool/builtin-orc.o > > HOSTCC scripts/objtool/check.o > > HOSTCC scripts/objtool/orc_gen.o > > HOSTCC scripts/objtool/orc_dump.o > > HOSTCC scripts/objtool/elf.o > > HOSTCC scripts/objtool/special.o > > HOSTCC scripts/objtool/objtool.o > > HOSTCC scripts/objtool/libstring.o > > HOSTCC scripts/objtool/str_error_r.o > > HOSTCC scripts/objtool/exec-cmd.o > > HOSTCC scripts/objtool/pager.o > > HOSTCC scripts/objtool/parse-options.o > > HOSTCC scripts/objtool/run-command.o > > HOSTCC scripts/objtool/sigchain.o > > HOSTCC scripts/objtool/subcmd-config.o > > AWK scripts/objtool/arch/x86/lib/inat-tables.c > > HOSTCC scripts/objtool/arch/x86/decode.o > > HOSTLD scripts/objtool/objtool > > That does look better. > > > [3] simplify distro package script > > > > The special handling in scripts/package/buildeb is no longer needed > > since all host programs are copied to linux-headers packages. > > I do see the benefits. In many ways objtool is a more natural fit in > the scripts dir. But there are also some downsides to this change: > > - This will make it harder to package objtool as a standalone tool. It > has a lot of functionality that could be useful to other non-kernel > projects. If it is really useful for other projects, I'd like to see it as a real standalone tool, i.e. split as a separate project. > - It shares libsubcmd with perf. Including the subcmd .c files from > tools is hacky. Yes, hacky. We are shifting the ugliness between C and Build system. But, this hack can be solved; if subcmd library is useful, you can copy only necessary code into the objtool directory. You do not need all helpers from libsubcmd. > - It's disruptive: it will break all the out-of-tree distro kernel > packaging scripts which now look for objtool in tools. All artifacts under scripts/ should be contained in the package. So, it should work. > You're right that objtool isn't a natural fit in tools, because it's > also used as part of the build. But it's not a natural fit in scripts > either. I think we've resolved most of those issues and it seems to be > working well these days. > > So instead of disrupting everything because "make mrproper" doesn't > work, I think I'd rather just do the following: > > diff --git a/Makefile b/Makefile > index ac5ac28a24e9..7e6696c9b862 100644 > --- a/Makefile > +++ b/Makefile > @@ -1364,7 +1364,7 @@ PHONY += $(mrproper-dirs) mrproper > $(mrproper-dirs): > $(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@) > > -mrproper: clean $(mrproper-dirs) > +mrproper: clean $(mrproper-dirs) tools/objtool_clean > $(call cmd,rmdirs) > $(call cmd,rmfiles) > Works, and the clean log is also brilliant. I see the same log even when there is nothing to clean. masahiro@grover:~/ref/linux$ make mrproper CLEAN . CLEAN arch/x86/entry/vdso CLEAN usr CLEAN arch/x86/tools CLEAN .tmp_versions CLEAN scripts/basic CLEAN scripts/kconfig CLEAN scripts/mod CLEAN scripts/selinux/genheaders CLEAN scripts/selinux/mdp CLEAN scripts DESCEND objtool CLEAN objtool CLEAN include/config include/generated arch/x86/include/generated CLEAN .config masahiro@grover:~/ref/linux$ make mrproper DESCEND objtool CLEAN objtool masahiro@grover:~/ref/linux$ make mrproper DESCEND objtool CLEAN objtool -- Best Regards Masahiro Yamada
