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 @@ -239,10 +239,10 @@ struct module_kobject *lookup_or_create_ * 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) /* * Format: __mod_device_table__kmod_____ @@ -279,7 +279,9 @@ static typeof(name) __mod_device_table(t */ #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); \ @@ -302,7 +304,7 @@ static typeof(name) __mod_device_table(t /* 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 @@ -24,6 +24,16 @@ #define __MODULE_INFO_PREFIX KBUILD_MODNAME "." #endif +/* 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, info) __MODULE_INFO_DISABLED(tag) +#else +#define MODULE_INFO_STRIP(tag, info) MODULE_INFO(tag, info) +#endif + /* Generic info of form tag = "info" */ #define MODULE_INFO(tag, info) \ static const char __UNIQUE_ID(modinfo)[] \ @@ -36,7 +46,7 @@ /* 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 ":" desc) + MODULE_INFO_STRIP(parm, #_parm ":" desc) struct kernel_param; --- a/kernel/module/Kconfig +++ b/kernel/module/Kconfig @@ -462,4 +462,11 @@ config MODULES_TREE_LOOKUP def_bool y depends on PERF_EVENTS || TRACING || CFI +config MODULE_STRIPPED + bool "Reduce module size" + depends on MODULES + help + Remove module parameter descriptions, author info, version, aliases, + device tables, etc. + endif # MODULES --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -1075,6 +1075,7 @@ const size_t modinfo_attrs_count = ARRAY static const char vermagic[] = VERMAGIC_STRING; +#if defined(CONFIG_MODVERSIONS) || !defined(CONFIG_MODULE_STRIPPED) int try_to_force_load(struct module *mod, const char *reason) { #ifdef CONFIG_MODULE_FORCE_LOAD @@ -1086,6 +1087,7 @@ int try_to_force_load(struct module *mod return -ENOEXEC; #endif } +#endif /* Parse tag=value strings from .modinfo section */ char *module_next_tag_pair(char *string, unsigned long *secsize) @@ -2579,9 +2581,11 @@ static void module_augment_kernel_taints 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; @@ -2595,6 +2599,7 @@ static int check_modinfo(struct module * info->name, modmagic, vermagic); return -ENOEXEC; } +#endif err = check_modinfo_livepatch(mod, info); if (err) --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1619,7 +1619,9 @@ static void read_symbols(const char *mod symname = remove_dot(info.strtab + sym->st_name); handle_symbol(mod, &info, sym, symname); +#ifndef CONFIG_MODULE_STRIPPED handle_moddevtable(mod, &info, sym, symname); +#endif } check_sec_ref(mod, &info); @@ -1832,7 +1834,9 @@ static void add_header(struct buffer *b, buf_printf(b, "#include \n"); buf_printf(b, "#include \n"); buf_printf(b, "\n"); +#ifndef CONFIG_MODULE_STRIPPED 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"); @@ -1846,11 +1850,13 @@ static void add_header(struct buffer *b, buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n"); buf_printf(b, "};\n"); +#ifndef CONFIG_MODULE_STRIPPED if (!external_module) buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n"); if (strstarts(mod->name, "drivers/staging")) buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n"); +#endif if (strstarts(mod->name, "tools/testing")) buf_printf(b, "\nMODULE_INFO(test, \"Y\");\n"); @@ -2004,11 +2010,13 @@ 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_buf(struct buffer *b, const char *fname) @@ -2109,12 +2117,14 @@ static void write_mod_c_file(struct modu add_extended_versions(&buf, mod); add_depends(&buf, mod); +#ifndef CONFIG_MODULE_STRIPPED buf_printf(&buf, "\n"); list_for_each_entry_safe(alias, next, &mod->aliases, node) { buf_printf(&buf, "MODULE_ALIAS(\"%s\");\n", alias->str); list_del(&alias->node); free(alias); } +#endif add_srcversion(&buf, mod);