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

[Joao Moreira]

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 Makefile
]

[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
* split up: move modinfo call removal by mbenes to the next patch
]

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(-)

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 61f87a99bf0a..9aba82d76659 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -251,6 +251,8 @@ endif
 # (needed for the shell)
 make-cmd = $(call escsq,$(subst \#,\\\#,$(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 $^),$^)
@@ -260,7 +262,7 @@ any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
 if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
 	@set -e;                                                             \
 	$(echo-cmd) $(cmd_$(1));                                             \
-	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) ),                  \
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 16923ba4b5b1..52264ce1b883 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 = LIVEPATCH $@
+      cmd_klp_convert = mv $@ $(@:.ko=.klp.o);				\
+			$(KLP_CONVERT) $(SLIST) $(@:.ko=.klp.o) $@
+
+define rule_ld_ko_o
+	$(call echo-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 30d752a4a6a6..d9fe972ed92e 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1977,6 +1977,10 @@ static void read_symbols(char *modname)
 					   "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);
 
@@ -2170,7 +2174,7 @@ static int add_versions(struct buffer *b, struct module *mod)
 	for (s = mod->unres; s; s = s->next) {
 		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 6a5e1515123b..dcb32a57be29 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -117,6 +117,7 @@ struct module {
 	int skip;
 	int has_init;
 	int has_cleanup;
+	int livepatch;
 	struct buffer dev_table_buf;
 	char	     srcversion[25];
 	int is_dot_o;
-- 
2.12.0