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

Joe Lawrence
2019-03-22T14:54:08Z

On Fri, Mar 01, 2019 at 11:13:10AM -0300, Joao Moreira wrote:
> From: Josh Poimboeuf <jpoimboe@redhat.com>
>
> 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@redhat.com>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
> Signed-off-by: Miroslav Benes <mbenes@suse.cz>
> Signed-off-by: Joao Moreira <jmoreira@suse.de>
> ---
> 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.

-- Joe