1 files changed, 149 insertions, 27 deletions

diff --git a/lib/codetag.c b/lib/codetag.c
index 5ace625f2328..545911cebd25 100644
--- a/lib/codetag.c
+++ b/lib/codetag.c
@@ -11,8 +11,14 @@ struct codetag_type {
 	struct list_head link;
 	unsigned int count;
 	struct idr mod_idr;
-	struct rw_semaphore mod_lock; /* protects mod_idr */
+	/*
+	 * protects mod_idr, next_mod_seq,
+	 * iter->mod_seq and cmod->mod_seq
+	 */
+	struct rw_semaphore mod_lock;
 	struct codetag_type_desc desc;
+	/* generates unique sequence number for module load */
+	unsigned long next_mod_seq;
 };
 
 struct codetag_range {
@@ -23,6 +29,7 @@ struct codetag_range {
 struct codetag_module {
 	struct module *mod;
 	struct codetag_range range;
+	unsigned long mod_seq;
 };
 
 static DEFINE_MUTEX(codetag_lock);
@@ -48,6 +55,7 @@ struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype)
 		.cmod = NULL,
 		.mod_id = 0,
 		.ct = NULL,
+		.mod_seq = 0,
 	};
 
 	return iter;
@@ -91,11 +99,13 @@ struct codetag *codetag_next_ct(struct codetag_iterator *iter)
 		if (!cmod)
 			break;
 
-		if (cmod != iter->cmod) {
+		if (!iter->cmod || iter->mod_seq != cmod->mod_seq) {
 			iter->cmod = cmod;
+			iter->mod_seq = cmod->mod_seq;
 			ct = get_first_module_ct(cmod);
-		} else
+		} else {
 			ct = get_next_module_ct(iter);
+		}
 
 		if (ct)
 			break;
@@ -125,7 +135,6 @@ static inline size_t range_size(const struct codetag_type *cttype,
 			cttype->desc.tag_size;
 }
 
-#ifdef CONFIG_MODULES
 static void *get_symbol(struct module *mod, const char *prefix, const char *name)
 {
 	DECLARE_SEQ_BUF(sb, KSYM_NAME_LEN);
@@ -150,22 +159,31 @@ static struct codetag_range get_section_range(struct module *mod,
 					      const char *section)
 {
 	return (struct codetag_range) {
-		get_symbol(mod, "__start_", section),
-		get_symbol(mod, "__stop_", section),
+		get_symbol(mod, CODETAG_SECTION_START_PREFIX, section),
+		get_symbol(mod, CODETAG_SECTION_STOP_PREFIX, section),
 	};
 }
 
+static const char *get_mod_name(__maybe_unused struct module *mod)
+{
+#ifdef CONFIG_MODULES
+	if (mod)
+		return mod->name;
+#endif
+	return "(built-in)";
+}
+
 static int codetag_module_init(struct codetag_type *cttype, struct module *mod)
 {
 	struct codetag_range range;
 	struct codetag_module *cmod;
+	int mod_id;
 	int err;
 
 	range = get_section_range(mod, cttype->desc.section);
 	if (!range.start || !range.stop) {
 		pr_warn("Failed to load code tags of type %s from the module %s\n",
-			cttype->desc.section,
-			mod ? mod->name : "(built-in)");
+			cttype->desc.section, get_mod_name(mod));
 		return -EINVAL;
 	}
 
@@ -183,11 +201,21 @@ static int codetag_module_init(struct codetag_type *cttype, struct module *mod)
 	cmod->range = range;
 
 	down_write(&cttype->mod_lock);
-	err = idr_alloc(&cttype->mod_idr, cmod, 0, 0, GFP_KERNEL);
-	if (err >= 0) {
-		cttype->count += range_size(cttype, &range);
-		if (cttype->desc.module_load)
-			cttype->desc.module_load(cttype, cmod);
+	cmod->mod_seq = ++cttype->next_mod_seq;
+	mod_id = idr_alloc(&cttype->mod_idr, cmod, 0, 0, GFP_KERNEL);
+	if (mod_id >= 0) {
+		if (cttype->desc.module_load) {
+			err = cttype->desc.module_load(mod, range.start, range.stop);
+			if (!err)
+				cttype->count += range_size(cttype, &range);
+			else
+				idr_remove(&cttype->mod_idr, mod_id);
+		} else {
+			cttype->count += range_size(cttype, &range);
+			err = 0;
+		}
+	} else {
+		err = mod_id;
 	}
 	up_write(&cttype->mod_lock);
 
@@ -199,26 +227,123 @@ static int codetag_module_init(struct codetag_type *cttype, struct module *mod)
 	return 0;
 }
 
-void codetag_load_module(struct module *mod)
+#ifdef CONFIG_MODULES
+#define CODETAG_SECTION_PREFIX	".codetag."
+
+/* Some codetag types need a separate module section */
+bool codetag_needs_module_section(struct module *mod, const char *name,
+				  unsigned long size)
+{
+	const char *type_name;
+	struct codetag_type *cttype;
+	bool ret = false;
+
+	if (strncmp(name, CODETAG_SECTION_PREFIX, strlen(CODETAG_SECTION_PREFIX)))
+		return false;
+
+	type_name = name + strlen(CODETAG_SECTION_PREFIX);
+	mutex_lock(&codetag_lock);
+	list_for_each_entry(cttype, &codetag_types, link) {
+		if (strcmp(type_name, cttype->desc.section) == 0) {
+			if (!cttype->desc.needs_section_mem)
+				break;
+
+			down_write(&cttype->mod_lock);
+			ret = cttype->desc.needs_section_mem(mod, size);
+			up_write(&cttype->mod_lock);
+			break;
+		}
+	}
+	mutex_unlock(&codetag_lock);
+
+	return ret;
+}
+
+void *codetag_alloc_module_section(struct module *mod, const char *name,
+				   unsigned long size, unsigned int prepend,
+				   unsigned long align)
 {
+	const char *type_name = name + strlen(CODETAG_SECTION_PREFIX);
 	struct codetag_type *cttype;
+	void *ret = ERR_PTR(-EINVAL);
+
+	mutex_lock(&codetag_lock);
+	list_for_each_entry(cttype, &codetag_types, link) {
+		if (strcmp(type_name, cttype->desc.section) == 0) {
+			if (WARN_ON(!cttype->desc.alloc_section_mem))
+				break;
+
+			down_write(&cttype->mod_lock);
+			ret = cttype->desc.alloc_section_mem(mod, size, prepend, align);
+			up_write(&cttype->mod_lock);
+			break;
+		}
+	}
+	mutex_unlock(&codetag_lock);
+
+	return ret;
+}
+
+void codetag_free_module_sections(struct module *mod)
+{
+	struct codetag_type *cttype;
+
+	mutex_lock(&codetag_lock);
+	list_for_each_entry(cttype, &codetag_types, link) {
+		if (!cttype->desc.free_section_mem)
+			continue;
+
+		down_write(&cttype->mod_lock);
+		cttype->desc.free_section_mem(mod, false);
+		up_write(&cttype->mod_lock);
+	}
+	mutex_unlock(&codetag_lock);
+}
+
+void codetag_module_replaced(struct module *mod, struct module *new_mod)
+{
+	struct codetag_type *cttype;
+
+	mutex_lock(&codetag_lock);
+	list_for_each_entry(cttype, &codetag_types, link) {
+		if (!cttype->desc.module_replaced)
+			continue;
+
+		down_write(&cttype->mod_lock);
+		cttype->desc.module_replaced(mod, new_mod);
+		up_write(&cttype->mod_lock);
+	}
+	mutex_unlock(&codetag_lock);
+}
+
+int codetag_load_module(struct module *mod)
+{
+	struct codetag_type *cttype;
+	int ret = 0;
 
 	if (!mod)
-		return;
+		return 0;
 
 	mutex_lock(&codetag_lock);
-	list_for_each_entry(cttype, &codetag_types, link)
-		codetag_module_init(cttype, mod);
+	list_for_each_entry(cttype, &codetag_types, link) {
+		ret = codetag_module_init(cttype, mod);
+		if (ret)
+			break;
+	}
 	mutex_unlock(&codetag_lock);
+
+	return ret;
 }
 
-bool codetag_unload_module(struct module *mod)
+void codetag_unload_module(struct module *mod)
 {
 	struct codetag_type *cttype;
-	bool unload_ok = true;
 
 	if (!mod)
-		return true;
+		return;
+
+	/* await any module's kfree_rcu() operations to complete */
+	kvfree_rcu_barrier();
 
 	mutex_lock(&codetag_lock);
 	list_for_each_entry(cttype, &codetag_types, link) {
@@ -235,22 +360,19 @@ bool codetag_unload_module(struct module *mod)
 		}
 		if (found) {
 			if (cttype->desc.module_unload)
-				if (!cttype->desc.module_unload(cttype, cmod))
-					unload_ok = false;
+				cttype->desc.module_unload(cmod->mod,
+					cmod->range.start, cmod->range.stop);
 
 			cttype->count -= range_size(cttype, &cmod->range);
 			idr_remove(&cttype->mod_idr, mod_id);
 			kfree(cmod);
 		}
 		up_write(&cttype->mod_lock);
+		if (found && cttype->desc.free_section_mem)
+			cttype->desc.free_section_mem(mod, true);
 	}
 	mutex_unlock(&codetag_lock);
-
-	return unload_ok;
 }
-
-#else /* CONFIG_MODULES */
-static int codetag_module_init(struct codetag_type *cttype, struct module *mod) { return 0; }
 #endif /* CONFIG_MODULES */
 
 struct codetag_type *