Re: [PATCH v2 5/8] modpost: Integrate klp-convert

[Joe Lawrence]

On 3/22/19 12:37 PM, Joao Moreira wrote:
> On 2019-03-22 11:54, Joe Lawrence wrote:
> > On Fri, Mar 01, 2019 at 11:13:10AM -0300, Joao Moreira wrote:
> > > From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> > >
> > > Create cmd_klp_convert and hook it into scripts/Makefile.modpost.
> > > cmd_klp_convert invokes klp-convert with the right arguments for the
> > > conversion of unresolved symbols inside a livepatch.
> > >
> > > [khlebnikov:
> > > * save cmd_ld_ko_o into .module.cmd, if_changed_rule doesn't do that
> > > * fix bashisms for debian where /bin/sh is a symlink to /bin/dash
> > > * rename rule_link_module to rule_ld_ko_o, otherwise arg-check inside
> > >    if_changed_rule compares cmd_link_module and cmd_ld_ko_o
> > > * check modinfo -F livepatch only if CONFIG_LIVEPATCH is true
> > > ]
> > >
> > > [mbenes:
> > > * remove modinfo call. LIVEPATCH_ in Makefiled
> > > ]
> > >
> > > [jmoreira:
> > > * split up: move the .livepatch file-based scheme for identifying
> > > livepatches to a previous patch, as it was required for correctly
> > > building Symbols.list there.
> > > ]
> > >
> > > Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> > > Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
> > > Signed-off-by: Miroslav Benes <mbenes@xxxxxxx>
> > > Signed-off-by: Joao Moreira <jmoreira@xxxxxxx>
> > > ---
> > >   scripts/Kbuild.include   |  4 +++-
> > >   scripts/Makefile.modpost | 16 +++++++++++++++-
> > >   scripts/mod/modpost.c    |  6 +++++-
> > >   scripts/mod/modpost.h    |  1 +
> > >   4 files changed, 24 insertions(+), 3 deletions(-)
> > >
> > >
> > > [ ... snip ... ]
> > >
> > > diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
> > > index 7d4af0d0accb..da779a185218 100644
> > > --- a/scripts/Makefile.modpost
> > > +++ b/scripts/Makefile.modpost
> > > @@ -125,8 +125,22 @@ quiet_cmd_ld_ko_o = LD [M]  $@
> > >                    -o $@ $(filter-out FORCE,$^) ;
> > >    \
> > >   	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
> > >
> > > +SLIST = $(objtree)/Symbols.list
> > > +KLP_CONVERT = scripts/livepatch/klp-convert
> > > +quiet_cmd_klp_convert = KLP $@
> > > +      cmd_klp_convert = mv $@ $(@:.ko=.klp.o);				\
> > > +			$(KLP_CONVERT) $(SLIST) $(@:.ko=.klp.o) $@
> > > +
> > > +define rule_ld_ko_o
> > > +	$(call cmd,ld_ko_o) $(cmd_ld_ko_o) ;				\
> >                             ^
> > Should there be a ';' semicolon here (and maybe a line-break) between
> > $(call cmd,ld_ko_o) and $(cmd_ld_ko_o)?
> >
> > I didn't see this in my x86_64 VM, but on a ppc64le box, I kept getting
> > really strange build errors that I traced to this line.  Without a
> > semicolon, the build was trying to run a make command with a linker
> > command smashed onto the end of it:
> >
> >    make -f ./arch/powerpc/Makefile.postlink crypto/xts.ko ld -r  -EL -m
> > elf64lppc -T ./scripts/module-common.lds -T
> > ./arch/powerpc/kernel/module.lds --save-restore-funcs  --build-id  -o
> > crypto/xts.ko crypto/xts.o crypto/xts.mod.o
> >
> >
> > Now, klp-convert looks like will need some ppc64le work as well, as
> > it's
> > confused about .TOC. symbols:
> >
> >      CC      samples/livepatch/livepatch-annotated-sample.mod.o
> >      CC      samples/livepatch/livepatch-callbacks-busymod.mod.o
> >      CC      samples/livepatch/livepatch-callbacks-demo.mod.o
> >      CC      samples/livepatch/livepatch-callbacks-mod.mod.o
> >      CC      samples/livepatch/livepatch-sample.mod.o
> >      CC      samples/livepatch/livepatch-shadow-fix1.mod.o
> >      CC      samples/livepatch/livepatch-shadow-fix2.mod.o
> >      CC      samples/livepatch/livepatch-shadow-mod.mod.o
> >      LD [M]  samples/livepatch/livepatch-annotated-sample.ko
> >      LD [M]  samples/livepatch/livepatch-callbacks-demo.ko
> >      KLP     samples/livepatch/livepatch-annotated-sample.ko
> >      LD [M]  samples/livepatch/livepatch-callbacks-mod.ko
> >      KLP     samples/livepatch/livepatch-callbacks-demo.ko
> >      LD [M]  samples/livepatch/livepatch-sample.ko
> >      LD [M]  samples/livepatch/livepatch-shadow-fix1.ko
> >    klp-convert: Define KLP_SYMPOS for the symbol: .TOC.
> >    Valid KLP_SYMPOS for symbol .TOC.:
> >
> >    [ ... snip listing of all .TOC's across the kernel ... ]
> >
> > but we can save that for another day.
>
> Hi Joe, first of all, thank you for you in-depth review. I did not have
> the time to go through everything yet, and I'll reply properly to the
> other comments soon. Yet, I would like to add a quick note here, since
> you are testing ppc64le. ppc64le is exactly one of the things I have
> been dealing with in the last two days, specifically the .TOC. symbols
> (there is also another bug related to converting relocations of symbols
> with index 0, but this one is architecture agnostic).
>
> If you would like to take a look, the fix is in the latest commit here:
> - https://github.com/SUSE/klp-convert/tree/fixppc64le
>
> I would be very glad if you have any comment or input on that, and I
> guess that if the fix is that simple, I can manage to squash it into v3.

Hi JoÃo,

I added https://github.com/SUSE/klp-convert/commit/69b89ef5c366 on top 
of my 
https://github.com/joe-lawrence/linux/tree/klp-convert-v2-rebase-review 
branch with positive results:

(No build klp-convert build complaints)

  % uname -r
  Linux ibm-p9z-21-lp26.mpc.lab.eng.bos.redhat.com 5.1.0-rc1+ #6 SMP 
Thu Mar 21 11:40:24 EDT 2019 ppc64le ppc64le ppc64le GNU/Linux

  % insmod samples/livepatch/livepatch-annotated-sample.ko
  % grep -o 'livepatch.*' /proc/cmdline
  livepatch=1

  % ./tools/testing/selftests/livepatch/test-livepatch.sh
  TEST: basic function patching ... ok
  TEST: multiple livepatches ... ok
  TEST: atomic replace livepatch ... ok
  TEST: klp-convert symbols ... ok

There may be more ppc64le specifics lurking, but if we could get samples 
and self-tests working, I think we'd be in good shape for v3.

-- Joe