kernel: add a patch that reduces module size by removing non-essential information (reduces default rootfs size by ~5k after lzma)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37255 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 200 insertions, 0 deletions

diff --git a/target/linux/generic/patches-3.9/204-module_strip.patch b/target/linux/generic/patches-3.9/204-module_strip.patch
new file mode 100644
index 0000000000..4b45156e02
--- /dev/null
+++ b/target/linux/generic/patches-3.9/204-module_strip.patch
@@ -0,0 +1,200 @@
+From: Felix Fietkau <nbd@openwrt.org>
+Subject: [PATCH] build: add a hack for removing non-essential module info
+
+Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+---
+--- a/include/linux/module.h
++++ b/include/linux/module.h
+@@ -82,7 +82,7 @@ void sort_extable(struct exception_table
+ void sort_main_extable(void);
+ void trim_init_extable(struct module *m);
+ 
+-#ifdef MODULE
++#if defined(MODULE) && !defined(CONFIG_MODULE_STRIPPED)
+ #define MODULE_GENERIC_TABLE(gtype,name)			\
+ extern const struct gtype##_id __mod_##gtype##_table		\
+   __attribute__ ((unused, alias(__stringify(name))))
+@@ -93,9 +93,10 @@ extern const struct gtype##_id __mod_##g
+ 
+ /* 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)
++#define MODULE_ALIAS(_alias) MODULE_INFO_STRIP(alias, _alias)
+ 
+ /*
+  * The following license idents are currently accepted as indicating free
+@@ -131,10 +132,10 @@ extern const struct gtype##_id __mod_##g
+  * Author(s), use "Name <email>" 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)
+ 
+ #define MODULE_DEVICE_TABLE(type,name)		\
+   MODULE_GENERIC_TABLE(type##_device,name)
+@@ -155,7 +156,9 @@ extern const struct gtype##_id __mod_##g
+ */
+ 
+ #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)					\
+ 	static struct module_version_attribute ___modver_attr = {	\
+@@ -177,7 +180,7 @@ extern const struct gtype##_id __mod_##g
+ /* 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)
+ 
+ /* Given an address, look for it in the exception tables */
+ const struct exception_table_entry *search_exception_tables(unsigned long add);
+--- a/include/linux/moduleparam.h
++++ b/include/linux/moduleparam.h
+@@ -16,6 +16,16 @@
+ /* 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)[]					  \
+@@ -23,8 +33,7 @@ static const char __UNIQUE_ID(name)[]			
+   = __stringify(tag) "=" info
+ #else  /* !MODULE */
+ /* This struct is here for syntactic coherency, it is not used */
+-#define __MODULE_INFO(tag, name, info)					  \
+-  struct __UNIQUE_ID(name) {}
++#define __MODULE_INFO(tag, name, info) __MODULE_INFO_DISABLED(name)
+ #endif
+ #define __MODULE_PARM_TYPE(name, _type)					  \
+   __MODULE_INFO(parmtype, name##type, #name ":" _type)
+@@ -32,7 +41,7 @@ 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
+@@ -1731,6 +1731,13 @@ config MODULE_SIG_HASH
+ 	default "sha384" if MODULE_SIG_SHA384
+ 	default "sha512" if MODULE_SIG_SHA512
+ 
++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 INIT_ALL_POSSIBLE
+--- a/kernel/module.c
++++ b/kernel/module.c
+@@ -2689,6 +2689,7 @@ static struct module *setup_load_info(st
+ 
+ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
+ {
++#ifndef CONFIG_MODULE_STRIPPED
+ 	const char *modmagic = get_modinfo(info, "vermagic");
+ 	int err;
+ 
+@@ -2715,6 +2716,7 @@ static int check_modinfo(struct module *
+ 		       " the quality is unknown, you have been warned.\n",
+ 		       mod->name);
+ 	}
++#endif
+ 
+ 	/* Set up license info based on the info section */
+ 	set_license(mod, get_modinfo(info, "license"));
+--- a/scripts/mod/modpost.c
++++ b/scripts/mod/modpost.c
+@@ -1738,7 +1738,9 @@ static void read_symbols(char *modname)
+ 		symname = info.strtab + sym->st_name;
+ 
+ 		handle_modversions(mod, &info, sym, symname);
++#ifndef CONFIG_MODULE_STRIPPED
+ 		handle_moddevtable(mod, &info, sym, symname);
++#endif
+ 	}
+ 	if (!is_vmlinux(modname) ||
+ 	     (is_vmlinux(modname) && vmlinux_section_warnings))
+@@ -1861,7 +1863,9 @@ static void add_header(struct buffer *b,
+ 	buf_printf(b, "#include <linux/vermagic.h>\n");
+ 	buf_printf(b, "#include <linux/compiler.h>\n");
+ 	buf_printf(b, "\n");
++#ifndef CONFIG_MODULE_STRIPPED
+ 	buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
++#endif
+ 	buf_printf(b, "\n");
+ 	buf_printf(b, "struct module __this_module\n");
+ 	buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
+@@ -1878,16 +1882,20 @@ 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
+ }
+ 
+ static void add_staging_flag(struct buffer *b, const char *name)
+ {
++#ifndef CONFIG_MODULE_STRIPPED
+ 	static const char *staging_dir = "drivers/staging";
+ 
+ 	if (strncmp(staging_dir, name, strlen(staging_dir)) == 0)
+ 		buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
++#endif
+ }
+ 
+ /**
+@@ -1979,11 +1987,13 @@ 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)
+@@ -2203,7 +2213,9 @@ int main(int argc, char **argv)
+ 		add_staging_flag(&buf, mod->name);
+ 		err |= add_versions(&buf, mod);
+ 		add_depends(&buf, mod, modules);
++#ifndef CONFIG_MODULE_STRIPPED
+ 		add_moddevtable(&buf, mod);
++#endif
+ 		add_srcversion(&buf, mod);
+ 
+ 		sprintf(fname, "%s.mod.c", mod->name);