From a779a482fb9b9f8fcdf8b2519c789b4b9bb5dd05 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Fri, 7 Jul 2017 16:56:48 +0200 Subject: build: add a hack for removing non-essential module info Signed-off-by: Felix Fietkau --- include/linux/module.h | 13 ++++++++----- include/linux/moduleparam.h | 15 ++++++++++++--- init/Kconfig | 7 +++++++ kernel/module.c | 5 ++++- scripts/mod/modpost.c | 12 ++++++++++++ 5 files changed, 43 insertions(+), 9 deletions(-) --- a/include/linux/module.h +++ b/include/linux/module.h @@ -157,6 +157,7 @@ extern void cleanup_module(void); /* Generic info of form tag = "info" */ #define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info) +#define MODULE_INFO_STRIP(tag, info) __MODULE_INFO_STRIP(tag, tag, info) /* For userspace: you can also call me... */ #define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias) @@ -216,12 +217,12 @@ extern void cleanup_module(void); * Author(s), use "Name " or just "Name", for multiple * authors use multiple MODULE_AUTHOR() statements/lines. */ -#define MODULE_AUTHOR(_author) MODULE_INFO(author, _author) +#define MODULE_AUTHOR(_author) MODULE_INFO_STRIP(author, _author) /* What your module does. */ -#define MODULE_DESCRIPTION(_description) MODULE_INFO(description, _description) +#define MODULE_DESCRIPTION(_description) MODULE_INFO_STRIP(description, _description) -#ifdef MODULE +#if defined(MODULE) && !defined(CONFIG_MODULE_STRIPPED) /* Creates an alias so file2alias.c can find device table. */ #define MODULE_DEVICE_TABLE(type, name) \ extern typeof(name) __mod_##type##__##name##_device_table \ @@ -248,7 +249,9 @@ extern typeof(name) __mod_##type##__##na */ #if defined(MODULE) || !defined(CONFIG_SYSFS) -#define MODULE_VERSION(_version) MODULE_INFO(version, _version) +#define MODULE_VERSION(_version) MODULE_INFO_STRIP(version, _version) +#elif defined(CONFIG_MODULE_STRIPPED) +#define MODULE_VERSION(_version) __MODULE_INFO_DISABLED(version) #else #define MODULE_VERSION(_version) \ MODULE_INFO(version, _version); \ @@ -271,7 +274,7 @@ extern typeof(name) __mod_##type##__##na /* Optional firmware file (or files) needed by the module * format is simply firmware file name. Multiple firmware * files require multiple MODULE_FIRMWARE() specifiers */ -#define MODULE_FIRMWARE(_firmware) MODULE_INFO(firmware, _firmware) +#define MODULE_FIRMWARE(_firmware) MODULE_INFO_STRIP(firmware, _firmware) #define MODULE_IMPORT_NS(ns) MODULE_INFO(import_ns, #ns) --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -20,10 +20,24 @@ /* Chosen so that structs with an unsigned long line up. */ #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long)) +/* This struct is here for syntactic coherency, it is not used */ +#define __MODULE_INFO_DISABLED(name) \ + struct __UNIQUE_ID(name) {} + +#ifdef CONFIG_MODULE_STRIPPED +#define __MODULE_INFO_STRIP(tag, name, info) __MODULE_INFO_DISABLED(name) +#else +#define __MODULE_INFO_STRIP(tag, name, info) __MODULE_INFO(tag, name, info) +#endif + +#ifdef MODULE #define __MODULE_INFO(tag, name, info) \ static const char __UNIQUE_ID(name)[] \ __used __attribute__((section(".modinfo"), unused, aligned(1))) \ = __MODULE_INFO_PREFIX __stringify(tag) "=" info +#else +#define __MODULE_INFO(tag, name, info) __MODULE_INFO_DISABLED(name) +#endif #define __MODULE_PARM_TYPE(name, _type) \ __MODULE_INFO(parmtype, name##type, #name ":" _type) @@ -31,7 +45,7 @@ static const char __UNIQUE_ID(name)[] /* One for each parameter, describing how to use it. Some files do multiple of these per line, so can't just use MODULE_INFO. */ #define MODULE_PARM_DESC(_parm, desc) \ - __MODULE_INFO(parm, _parm, #_parm ":" desc) + __MODULE_INFO_STRIP(parm, _parm, #_parm ":" desc) struct kernel_param; --- a/init/Kconfig +++ b/init/Kconfig @@ -2195,6 +2195,13 @@ config TRIM_UNUSED_KSYMS If unsure, or if you need to build out-of-tree modules, say N. +config MODULE_STRIPPED + bool "Reduce module size" + depends on MODULES + help + Remove module parameter descriptions, author info, version, aliases, + device tables, etc. + endif # MODULES config MODULES_TREE_LOOKUP --- a/kernel/module.c +++ b/kernel/module.c @@ -3110,9 +3110,11 @@ static int setup_load_info(struct load_i static int check_modinfo(struct module *mod, struct load_info *info, int flags) { - const char *modmagic = get_modinfo(info, "vermagic"); int err; +#ifndef CONFIG_MODULE_STRIPPED + const char *modmagic = get_modinfo(info, "vermagic"); + if (flags & MODULE_INIT_IGNORE_VERMAGIC) modmagic = NULL; @@ -3133,6 +3135,7 @@ static int check_modinfo(struct module * mod->name); add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK); } +#endif check_modinfo_retpoline(mod, info); --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -2056,7 +2056,9 @@ static void read_symbols(const char *mod symname = remove_dot(info.strtab + sym->st_name); handle_modversions(mod, &info, sym, symname); +#ifndef CONFIG_MODULE_STRIPPED handle_moddevtable(mod, &info, sym, symname); +#endif } /* Apply symbol namespaces from __kstrtabns_ entries. */ @@ -2270,8 +2272,10 @@ static void add_header(struct buffer *b, buf_printf(b, "\n"); buf_printf(b, "BUILD_SALT;\n"); buf_printf(b, "\n"); +#ifndef CONFIG_MODULE_STRIPPED buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n"); buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n"); +#endif buf_printf(b, "\n"); buf_printf(b, "__visible struct module __this_module\n"); buf_printf(b, "__section(.gnu.linkonce.this_module) = {\n"); @@ -2288,8 +2292,10 @@ static void add_header(struct buffer *b, static void add_intree_flag(struct buffer *b, int is_intree) { +#ifndef CONFIG_MODULE_STRIPPED if (is_intree) buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); +#endif } /* Cannot check for assembler */ @@ -2302,8 +2308,10 @@ static void add_retpoline(struct buffer static void add_staging_flag(struct buffer *b, const char *name) { +#ifndef CONFIG_MODULE_STRIPPED if (strstarts(name, "drivers/staging")) buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); +#endif } /** @@ -2387,11 +2395,13 @@ static void add_depends(struct buffer *b static void add_srcversion(struct buffer *b, struct module *mod) { +#ifndef CONFIG_MODULE_STRIPPED if (mod->srcversion[0]) { buf_printf(b, "\n"); buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n", mod->srcversion); } +#endif } static void write_if_changed(struct buffer *b, const char *fname) @@ -2661,7 +2671,9 @@ int main(int argc, char **argv) add_staging_flag(&buf, mod->name); err |= add_versions(&buf, mod); add_depends(&buf, mod); +#ifndef CONFIG_MODULE_STRIPPED add_moddevtable(&buf, mod); +#endif add_srcversion(&buf, mod); sprintf(fname, "%s.mod.c", mod->name);