1 files changed, 121 insertions, 32 deletions

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 7ea59dc4926b..be89921d60b6 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -33,6 +33,10 @@ static bool module_enabled;
 static bool modversions;
 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
 static bool all_versions;
+/* Is CONFIG_BASIC_MODVERSIONS set? */
+static bool basic_modversions;
+/* Is CONFIG_EXTENDED_MODVERSIONS set? */
+static bool extended_modversions;
 /* If we are modposting external module set to 1 */
 static bool external_module;
 /* Only warn about unresolved symbols */
@@ -94,6 +98,18 @@ static inline bool strends(const char *str, const char *postfix)
 	return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
 }
 
+/**
+ * get_basename - return the last part of a pathname.
+ *
+ * @path: path to extract the filename from.
+ */
+const char *get_basename(const char *path)
+{
+	const char *tail = strrchr(path, '/');
+
+	return tail ? tail + 1 : path;
+}
+
 char *read_text_file(const char *filename)
 {
 	struct stat st;
@@ -186,8 +202,8 @@ static struct module *new_module(const char *name, size_t namelen)
 
 	/*
 	 * Set mod->is_gpl_compatible to true by default. If MODULE_LICENSE()
-	 * is missing, do not check the use for EXPORT_SYMBOL_GPL() becasue
-	 * modpost will exit wiht error anyway.
+	 * is missing, do not check the use for EXPORT_SYMBOL_GPL() because
+	 * modpost will exit with an error anyway.
 	 */
 	mod->is_gpl_compatible = true;
 
@@ -503,6 +519,9 @@ static int parse_elf(struct elf_info *info, const char *filename)
 			info->modinfo_len = sechdrs[i].sh_size;
 		} else if (!strcmp(secname, ".export_symbol")) {
 			info->export_symbol_secndx = i;
+		} else if (!strcmp(secname, ".no_trim_symbol")) {
+			info->no_trim_symbol = (void *)hdr + sechdrs[i].sh_offset;
+			info->no_trim_symbol_len = sechdrs[i].sh_size;
 		}
 
 		if (sechdrs[i].sh_type == SHT_SYMTAB) {
@@ -1454,14 +1473,8 @@ static void extract_crcs_for_object(const char *object, struct module *mod)
 	const char *base;
 	int dirlen, ret;
 
-	base = strrchr(object, '/');
-	if (base) {
-		base++;
-		dirlen = base - object;
-	} else {
-		dirlen = 0;
-		base = object;
-	}
+	base = get_basename(object);
+	dirlen = base - object;
 
 	ret = snprintf(cmd_file, sizeof(cmd_file), "%.*s.%s.cmd",
 		       dirlen, object, base);
@@ -1562,6 +1575,14 @@ static void read_symbols(const char *modname)
 	/* strip trailing .o */
 	mod = new_module(modname, strlen(modname) - strlen(".o"));
 
+	/* save .no_trim_symbol section for later use */
+	if (info.no_trim_symbol_len) {
+		mod->no_trim_symbol = xmalloc(info.no_trim_symbol_len);
+		memcpy(mod->no_trim_symbol, info.no_trim_symbol,
+		       info.no_trim_symbol_len);
+		mod->no_trim_symbol_len = info.no_trim_symbol_len;
+	}
+
 	if (!mod->is_vmlinux) {
 		license = get_modinfo(&info, "license");
 		if (!license)
@@ -1581,7 +1602,7 @@ static void read_symbols(const char *modname)
 						     namespace);
 		}
 
-		if (extra_warn && !get_modinfo(&info, "description"))
+		if (!get_modinfo(&info, "description"))
 			warn("missing MODULE_DESCRIPTION() in %s\n", modname);
 	}
 
@@ -1688,11 +1709,7 @@ static void check_exports(struct module *mod)
 		s->crc_valid = exp->crc_valid;
 		s->crc = exp->crc;
 
-		basename = strrchr(mod->name, '/');
-		if (basename)
-			basename++;
-		else
-			basename = mod->name;
+		basename = get_basename(mod->name);
 
 		if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) {
 			modpost_log(!allow_missing_ns_imports,
@@ -1724,15 +1741,34 @@ static void handle_white_list_exports(const char *white_list)
 	free(buf);
 }
 
+/*
+ * Keep symbols recorded in the .no_trim_symbol section. This is necessary to
+ * prevent CONFIG_TRIM_UNUSED_KSYMS from dropping EXPORT_SYMBOL because
+ * symbol_get() relies on the symbol being present in the ksymtab for lookups.
+ */
+static void keep_no_trim_symbols(struct module *mod)
+{
+	unsigned long size = mod->no_trim_symbol_len;
+
+	for (char *s = mod->no_trim_symbol; s; s = next_string(s , &size)) {
+		struct symbol *sym;
+
+		/*
+		 * If find_symbol() returns NULL, this symbol is not provided
+		 * by any module, and symbol_get() will fail.
+		 */
+		sym = find_symbol(s);
+		if (sym)
+			sym->used = true;
+	}
+}
+
 static void check_modname_len(struct module *mod)
 {
 	const char *mod_name;
 
-	mod_name = strrchr(mod->name, '/');
-	if (mod_name == NULL)
-		mod_name = mod->name;
-	else
-		mod_name++;
+	mod_name = get_basename(mod->name);
+
 	if (strlen(mod_name) >= MODULE_NAME_LEN)
 		error("module name is too long [%s.ko]\n", mod->name);
 }
@@ -1806,13 +1842,56 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod)
 }
 
 /**
+ * Record CRCs for unresolved symbols, supporting long names
+ */
+static void add_extended_versions(struct buffer *b, struct module *mod)
+{
+	struct symbol *s;
+
+	if (!extended_modversions)
+		return;
+
+	buf_printf(b, "\n");
+	buf_printf(b, "static const u32 ____version_ext_crcs[]\n");
+	buf_printf(b, "__used __section(\"__version_ext_crcs\") = {\n");
+	list_for_each_entry(s, &mod->unresolved_symbols, list) {
+		if (!s->module)
+			continue;
+		if (!s->crc_valid) {
+			warn("\"%s\" [%s.ko] has no CRC!\n",
+				s->name, mod->name);
+			continue;
+		}
+		buf_printf(b, "\t0x%08x,\n", s->crc);
+	}
+	buf_printf(b, "};\n");
+
+	buf_printf(b, "static const char ____version_ext_names[]\n");
+	buf_printf(b, "__used __section(\"__version_ext_names\") =\n");
+	list_for_each_entry(s, &mod->unresolved_symbols, list) {
+		if (!s->module)
+			continue;
+		if (!s->crc_valid)
+			/*
+			 * We already warned on this when producing the crc
+			 * table.
+			 * We need to skip its name too, as the indexes in
+			 * both tables need to align.
+			 */
+			continue;
+		buf_printf(b, "\t\"%s\\0\"\n", s->name);
+	}
+	buf_printf(b, ";\n");
+}
+
+/**
  * Record CRCs for unresolved symbols
  **/
 static void add_versions(struct buffer *b, struct module *mod)
 {
 	struct symbol *s;
 
-	if (!modversions)
+	if (!basic_modversions)
 		return;
 
 	buf_printf(b, "\n");
@@ -1828,11 +1907,16 @@ static void add_versions(struct buffer *b, struct module *mod)
 			continue;
 		}
 		if (strlen(s->name) >= MODULE_NAME_LEN) {
-			error("too long symbol \"%s\" [%s.ko]\n",
-			      s->name, mod->name);
-			break;
+			if (extended_modversions) {
+				/* this symbol will only be in the extended info */
+				continue;
+			} else {
+				error("too long symbol \"%s\" [%s.ko]\n",
+				      s->name, mod->name);
+				break;
+			}
 		}
-		buf_printf(b, "\t{ %#8x, \"%s\" },\n",
+		buf_printf(b, "\t{ 0x%08x, \"%s\" },\n",
 			   s->crc, s->name);
 	}
 
@@ -1861,11 +1945,7 @@ static void add_depends(struct buffer *b, struct module *mod)
 			continue;
 
 		s->module->seen = true;
-		p = strrchr(s->module->name, '/');
-		if (p)
-			p++;
-		else
-			p = s->module->name;
+		p = get_basename(s->module->name);
 		buf_printf(b, "%s%s", first ? "" : ",", p);
 		first = 0;
 	}
@@ -1961,6 +2041,7 @@ static void write_mod_c_file(struct module *mod)
 	add_header(&buf, mod);
 	add_exported_symbols(&buf, mod);
 	add_versions(&buf, mod);
+	add_extended_versions(&buf, mod);
 	add_depends(&buf, mod);
 
 	buf_printf(&buf, "\n");
@@ -2126,7 +2207,7 @@ int main(int argc, char **argv)
 	LIST_HEAD(dump_lists);
 	struct dump_list *dl, *dl2;
 
-	while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:")) != -1) {
+	while ((opt = getopt(argc, argv, "ei:MmnT:to:au:WwENd:xb")) != -1) {
 		switch (opt) {
 		case 'e':
 			external_module = true;
@@ -2175,6 +2256,12 @@ int main(int argc, char **argv)
 		case 'd':
 			missing_namespace_deps = optarg;
 			break;
+		case 'b':
+			basic_modversions = true;
+			break;
+		case 'x':
+			extended_modversions = true;
+			break;
 		default:
 			exit(1);
 		}
@@ -2195,6 +2282,8 @@ int main(int argc, char **argv)
 		read_symbols_from_files(files_source);
 
 	list_for_each_entry(mod, &modules, list) {
+		keep_no_trim_symbols(mod);
+
 		if (mod->dump_file || mod->is_vmlinux)
 			continue;