Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching

Pull livepatching updates from Jiri Kosina:

 - fix for patching modules that contain .altinstructions or
   .parainstructions sections, from Jessica Yu

 - make TAINT_LIVEPATCH a per-module flag (so that it's immediately
   clear which module caused the taint), from Josh Poimboeuf

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  livepatch/module: make TAINT_LIVEPATCH module-specific
  Documentation: livepatch: add section about arch-specific code
  livepatch/x86: apply alternatives and paravirt patches after relocations
  livepatch: use arch_klp_init_object_loaded() to finish arch-specific tasks

2 files changed, 22 insertions, 10 deletions

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 8bbe50704621..af4643873e71 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -274,7 +274,6 @@ static int klp_write_object_relocations(struct module *pmod,
 
 	objname = klp_is_module(obj) ? obj->name : "vmlinux";
 
-	module_disable_ro(pmod);
 	/* For each klp relocation section */
 	for (i = 1; i < pmod->klp_info->hdr.e_shnum; i++) {
 		sec = pmod->klp_info->sechdrs + i;
@@ -309,7 +308,6 @@ static int klp_write_object_relocations(struct module *pmod,
 			break;
 	}
 
-	module_enable_ro(pmod, true);
 	return ret;
 }
 
@@ -547,9 +545,6 @@ static int __klp_enable_patch(struct klp_patch *patch)
 	    list_prev_entry(patch, list)->state == KLP_DISABLED)
 		return -EBUSY;
 
-	pr_notice_once("tainting kernel with TAINT_LIVEPATCH\n");
-	add_taint(TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
-
 	pr_notice("enabling patch '%s'\n", patch->mod->name);
 
 	klp_for_each_object(patch, obj) {
@@ -763,6 +758,12 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func)
 				    func->old_sympos ? func->old_sympos : 1);
 }
 
+/* Arches may override this to finish any remaining arch-specific tasks */
+void __weak arch_klp_init_object_loaded(struct klp_patch *patch,
+					struct klp_object *obj)
+{
+}
+
 /* parts of the initialization that is done only when the object is loaded */
 static int klp_init_object_loaded(struct klp_patch *patch,
 				  struct klp_object *obj)
@@ -770,9 +771,15 @@ static int klp_init_object_loaded(struct klp_patch *patch,
 	struct klp_func *func;
 	int ret;
 
+	module_disable_ro(patch->mod);
 	ret = klp_write_object_relocations(patch->mod, obj);
-	if (ret)
+	if (ret) {
+		module_enable_ro(patch->mod, true);
 		return ret;
+	}
+
+	arch_klp_init_object_loaded(patch, obj);
+	module_enable_ro(patch->mod, true);
 
 	klp_for_each_func(obj, func) {
 		ret = klp_find_object_symbol(obj->name, func->old_name,
diff --git a/kernel/module.c b/kernel/module.c
index 529efae9f481..f57dd63186e6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1149,6 +1149,8 @@ static size_t module_flags_taint(struct module *mod, char *buf)
 		buf[l++] = 'C';
 	if (mod->taints & (1 << TAINT_UNSIGNED_MODULE))
 		buf[l++] = 'E';
+	if (mod->taints & (1 << TAINT_LIVEPATCH))
+		buf[l++] = 'K';
 	/*
 	 * TAINT_FORCED_RMMOD: could be added.
 	 * TAINT_CPU_OUT_OF_SPEC, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
@@ -2792,14 +2794,17 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l
 }
 
 #ifdef CONFIG_LIVEPATCH
-static int find_livepatch_modinfo(struct module *mod, struct load_info *info)
+static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
 {
-	mod->klp = get_modinfo(info, "livepatch") ? true : false;
+	if (get_modinfo(info, "livepatch")) {
+		mod->klp = true;
+		add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
+	}
 
 	return 0;
 }
 #else /* !CONFIG_LIVEPATCH */
-static int find_livepatch_modinfo(struct module *mod, struct load_info *info)
+static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
 {
 	if (get_modinfo(info, "livepatch")) {
 		pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
@@ -2969,7 +2974,7 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
 			"is unknown, you have been warned.\n", mod->name);
 	}
 
-	err = find_livepatch_modinfo(mod, info);
+	err = check_modinfo_livepatch(mod, info);
 	if (err)
 		return err;