Adding CCs...
On Wed, 30 Jan 2019, 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>
I'm definitely not an expert on this topic (and we talked about it in the
past off-list), but I'd simplify the SoB chain. At least you don't need my
SoB there. I'm happy that you took the code and transformed it.
> ---
> 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(-)
>
> diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
> index 30816037036e..c30a8573c816 100644
> --- a/scripts/Kbuild.include
> +++ b/scripts/Kbuild.include
> @@ -239,6 +239,8 @@ endif
> # (needed for the shell)
> make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
>
> +save-cmd = printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd
> +
> # Find any prerequisites that is newer than target or that does not exist.
> # PHONY targets skipped in both cases.
> any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
> @@ -246,7 +248,7 @@ any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
> # Execute command if command has changed or prerequisite(s) are updated.
> if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
> $(cmd); \
> - printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
> + $(save-cmd), @:)
>
> # Execute the command and also postprocess generated .d dependencies file.
> if_changed_dep = $(if $(strip $(any-prereq) $(arg-check)),$(cmd_and_fixdep),@:)
> 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) ; \
> + $(call save-cmd,ld_ko_o) ; \
> + $(if $(CONFIG_LIVEPATCH), \
> + $(if $(wildcard $(MODVERDIR)/$(basetarget).livepatch), \
> + $(call echo-cmd,klp_convert) $(cmd_klp_convert) ))
> +endef
> +
> $(modules): %.ko :%.o %.mod.o FORCE
> - +$(call if_changed,ld_ko_o)
> + +$(call if_changed_rule,ld_ko_o)
>
> targets += $(modules)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 26bf886bd168..1dfc34d8b668 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -1979,6 +1979,10 @@ static void read_symbols(const char *modname)
> license = get_next_modinfo(&info, "license", license);
> }
>
> + /* Livepatch modules have unresolved symbols resolved by klp-convert */
> + if (get_modinfo(info.modinfo, info.modinfo_len, "livepatch"))
> + mod->livepatch = 1;
> +
> for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
> symname = remove_dot(info.strtab + sym->st_name);
>
> @@ -2106,7 +2110,7 @@ static int check_exports(struct module *mod)
> const char *basename;
> exp = find_symbol(s->name);
> if (!exp || exp->module == mod) {
> - if (have_vmlinux && !s->weak) {
> + if (have_vmlinux && !s->weak && !mod->livepatch) {
> if (warn_unresolved) {
> warn("\"%s\" [%s.ko] undefined!\n",
> s->name, mod->name);
> diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
> index 8453d6ac2f77..2acfaae064ec 100644
> --- a/scripts/mod/modpost.h
> +++ b/scripts/mod/modpost.h
> @@ -118,6 +118,7 @@ struct module {
> int skip;
> int has_init;
> int has_cleanup;
> + int livepatch;
> struct buffer dev_table_buf;
> char srcversion[25];
> int is_dot_o;
> --
> 2.16.4
>
Miroslav
