add an optional config option for stripping all unnecessary symbol exports from the kernel image

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@17181 3c298f89-4303-0410-b956-a3cf2f4a3e73

2 files changed, 234 insertions, 0 deletions

diff --git a/target/linux/generic-2.6/patches-2.6.28/027-module_exports.patch b/target/linux/generic-2.6/patches-2.6.28/027-module_exports.patch
new file mode 100644
index 000000000..2a4483262
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.28/027-module_exports.patch
@@ -0,0 +1,117 @@
+--- a/Makefile
++++ b/Makefile
+@@ -963,7 +963,7 @@ prepare: prepare0
+ # Leave this as default for preprocessing vmlinux.lds.S, which is now
+ # done in arch/$(ARCH)/kernel/Makefile
+ 
+-export CPPFLAGS_vmlinux.lds += -P -C -U$(ARCH)
++export CPPFLAGS_vmlinux.lds += -P -C -U$(ARCH) $(EXTRA_LDSFLAGS)
+ 
+ # The asm symlink changes when $(ARCH) changes.
+ # Detect this and ask user to run make mrproper
+--- a/include/asm-generic/vmlinux.lds.h
++++ b/include/asm-generic/vmlinux.lds.h
+@@ -2,6 +2,18 @@
+ #define LOAD_OFFSET 0
+ #endif
+ 
++#ifndef SYMTAB_KEEP_STR
++#define SYMTAB_KEEP_STR *(__ksymtab_strings.*)
++#endif
++
++#ifndef SYMTAB_KEEP
++#define SYMTAB_KEEP *(__ksymtab.*)
++#endif
++
++#ifndef SYMTAB_KEEP_GPL
++#define SYMTAB_KEEP_GPL *(__ksymtab_gpl.*)
++#endif
++
+ #ifndef VMLINUX_SYMBOL
+ #define VMLINUX_SYMBOL(_sym_) _sym_
+ #endif
+@@ -124,35 +136,35 @@
+ 	/* Kernel symbol table: Normal symbols */			\
+ 	__ksymtab         : AT(ADDR(__ksymtab) - LOAD_OFFSET) {		\
+ 		VMLINUX_SYMBOL(__start___ksymtab) = .;			\
+-		*(__ksymtab)						\
++		SYMTAB_KEEP						\
+ 		VMLINUX_SYMBOL(__stop___ksymtab) = .;			\
+ 	}								\
+ 									\
+ 	/* Kernel symbol table: GPL-only symbols */			\
+ 	__ksymtab_gpl     : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) {	\
+ 		VMLINUX_SYMBOL(__start___ksymtab_gpl) = .;		\
+-		*(__ksymtab_gpl)					\
++		SYMTAB_KEEP_GPL						\
+ 		VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .;		\
+ 	}								\
+ 									\
+ 	/* Kernel symbol table: Normal unused symbols */		\
+ 	__ksymtab_unused  : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) {	\
+ 		VMLINUX_SYMBOL(__start___ksymtab_unused) = .;		\
+-		*(__ksymtab_unused)					\
++		*(__ksymtab_unused.*)					\
+ 		VMLINUX_SYMBOL(__stop___ksymtab_unused) = .;		\
+ 	}								\
+ 									\
+ 	/* Kernel symbol table: GPL-only unused symbols */		\
+ 	__ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \
+ 		VMLINUX_SYMBOL(__start___ksymtab_unused_gpl) = .;	\
+-		*(__ksymtab_unused_gpl)					\
++		*(__ksymtab_unused_gpl.*)				\
+ 		VMLINUX_SYMBOL(__stop___ksymtab_unused_gpl) = .;	\
+ 	}								\
+ 									\
+ 	/* Kernel symbol table: GPL-future-only symbols */		\
+ 	__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
+ 		VMLINUX_SYMBOL(__start___ksymtab_gpl_future) = .;	\
+-		*(__ksymtab_gpl_future)					\
++		*(__ksymtab_gpl_future.*)				\
+ 		VMLINUX_SYMBOL(__stop___ksymtab_gpl_future) = .;	\
+ 	}								\
+ 									\
+@@ -193,7 +205,13 @@
+ 									\
+ 	/* Kernel symbol table: strings */				\
+         __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
+-		*(__ksymtab_strings)					\
++		SYMTAB_KEEP_STR						\
++	}								\
++									\
++	/DISCARD/ : {							\
++		*(__ksymtab.*)						\
++		*(__ksymtab_gpl.*)					\
++		*(__ksymtab_strings.*)					\
+ 	}								\
+ 									\
+ 	/* __*init sections */						\
+--- a/include/linux/module.h
++++ b/include/linux/module.h
+@@ -187,16 +187,24 @@ void *__symbol_get_gpl(const char *symbo
+ #define __CRC_SYMBOL(sym, sec)
+ #endif
+ 
++#ifdef MODULE
++#define __EXPORT_SUFFIX(sym)
++#else
++#define __EXPORT_SUFFIX(sym) "." #sym
++#endif
++
+ /* For every exported symbol, place a struct in the __ksymtab section */
+ #define __EXPORT_SYMBOL(sym, sec)				\
+ 	extern typeof(sym) sym;					\
+ 	__CRC_SYMBOL(sym, sec)					\
+ 	static const char __kstrtab_##sym[]			\
+-	__attribute__((section("__ksymtab_strings"), aligned(1))) \
++	__attribute__((section("__ksymtab_strings"		\
++	  __EXPORT_SUFFIX(sym)), aligned(1)))			\
+ 	= MODULE_SYMBOL_PREFIX #sym;                    	\
+ 	static const struct kernel_symbol __ksymtab_##sym	\
+ 	__used							\
+-	__attribute__((section("__ksymtab" sec), unused))	\
++	__attribute__((section("__ksymtab" sec			\
++	  __EXPORT_SUFFIX(sym)), unused))			\
+ 	= { (unsigned long)&sym, __kstrtab_##sym }
+ 
+ #define EXPORT_SYMBOL(sym)					\
diff --git a/target/linux/generic-2.6/patches-2.6.30/028-module_exports.patch b/target/linux/generic-2.6/patches-2.6.30/028-module_exports.patch
new file mode 100644
index 000000000..ec037b30e
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.30/028-module_exports.patch
@@ -0,0 +1,117 @@
+--- a/include/asm-generic/vmlinux.lds.h
++++ b/include/asm-generic/vmlinux.lds.h
+@@ -4,6 +4,18 @@
+ #define LOAD_OFFSET 0
+ #endif
+ 
++#ifndef SYMTAB_KEEP_STR
++#define SYMTAB_KEEP_STR *(__ksymtab_strings.*)
++#endif
++
++#ifndef SYMTAB_KEEP
++#define SYMTAB_KEEP *(__ksymtab.*)
++#endif
++
++#ifndef SYMTAB_KEEP_GPL
++#define SYMTAB_KEEP_GPL *(__ksymtab_gpl.*)
++#endif
++
+ #ifndef VMLINUX_SYMBOL
+ #define VMLINUX_SYMBOL(_sym_) _sym_
+ #endif
+@@ -176,35 +188,35 @@
+ 	/* Kernel symbol table: Normal symbols */			\
+ 	__ksymtab         : AT(ADDR(__ksymtab) - LOAD_OFFSET) {		\
+ 		VMLINUX_SYMBOL(__start___ksymtab) = .;			\
+-		*(__ksymtab)						\
++		SYMTAB_KEEP						\
+ 		VMLINUX_SYMBOL(__stop___ksymtab) = .;			\
+ 	}								\
+ 									\
+ 	/* Kernel symbol table: GPL-only symbols */			\
+ 	__ksymtab_gpl     : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) {	\
+ 		VMLINUX_SYMBOL(__start___ksymtab_gpl) = .;		\
+-		*(__ksymtab_gpl)					\
++		SYMTAB_KEEP_GPL						\
+ 		VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .;		\
+ 	}								\
+ 									\
+ 	/* Kernel symbol table: Normal unused symbols */		\
+ 	__ksymtab_unused  : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) {	\
+ 		VMLINUX_SYMBOL(__start___ksymtab_unused) = .;		\
+-		*(__ksymtab_unused)					\
++		*(__ksymtab_unused.*)					\
+ 		VMLINUX_SYMBOL(__stop___ksymtab_unused) = .;		\
+ 	}								\
+ 									\
+ 	/* Kernel symbol table: GPL-only unused symbols */		\
+ 	__ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \
+ 		VMLINUX_SYMBOL(__start___ksymtab_unused_gpl) = .;	\
+-		*(__ksymtab_unused_gpl)					\
++		*(__ksymtab_unused_gpl.*)				\
+ 		VMLINUX_SYMBOL(__stop___ksymtab_unused_gpl) = .;	\
+ 	}								\
+ 									\
+ 	/* Kernel symbol table: GPL-future-only symbols */		\
+ 	__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
+ 		VMLINUX_SYMBOL(__start___ksymtab_gpl_future) = .;	\
+-		*(__ksymtab_gpl_future)					\
++		*(__ksymtab_gpl_future.*)				\
+ 		VMLINUX_SYMBOL(__stop___ksymtab_gpl_future) = .;	\
+ 	}								\
+ 									\
+@@ -245,7 +257,13 @@
+ 									\
+ 	/* Kernel symbol table: strings */				\
+         __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
+-		*(__ksymtab_strings)					\
++		SYMTAB_KEEP_STR						\
++	}								\
++									\
++	/DISCARD/ : {							\
++		*(__ksymtab.*)						\
++		*(__ksymtab_gpl.*)					\
++		*(__ksymtab_strings.*)					\
+ 	}								\
+ 									\
+ 	/* __*init sections */						\
+--- a/include/linux/module.h
++++ b/include/linux/module.h
+@@ -187,16 +187,24 @@ void *__symbol_get_gpl(const char *symbo
+ #define __CRC_SYMBOL(sym, sec)
+ #endif
+ 
++#ifdef MODULE
++#define __EXPORT_SUFFIX(sym)
++#else
++#define __EXPORT_SUFFIX(sym) "." #sym
++#endif
++
+ /* For every exported symbol, place a struct in the __ksymtab section */
+ #define __EXPORT_SYMBOL(sym, sec)				\
+ 	extern typeof(sym) sym;					\
+ 	__CRC_SYMBOL(sym, sec)					\
+ 	static const char __kstrtab_##sym[]			\
+-	__attribute__((section("__ksymtab_strings"), aligned(1))) \
++	__attribute__((section("__ksymtab_strings"		\
++	  __EXPORT_SUFFIX(sym)), aligned(1)))			\
+ 	= MODULE_SYMBOL_PREFIX #sym;                    	\
+ 	static const struct kernel_symbol __ksymtab_##sym	\
+ 	__used							\
+-	__attribute__((section("__ksymtab" sec), unused))	\
++	__attribute__((section("__ksymtab" sec			\
++	  __EXPORT_SUFFIX(sym)), unused))			\
+ 	= { (unsigned long)&sym, __kstrtab_##sym }
+ 
+ #define EXPORT_SYMBOL(sym)					\
+--- a/Makefile
++++ b/Makefile
+@@ -994,7 +994,7 @@ prepare: prepare0
+ # Leave this as default for preprocessing vmlinux.lds.S, which is now
+ # done in arch/$(ARCH)/kernel/Makefile
+ 
+-export CPPFLAGS_vmlinux.lds += -P -C -U$(ARCH)
++export CPPFLAGS_vmlinux.lds += -P -C -U$(ARCH) $(EXTRA_LDSFLAGS)
+ 
+ # The asm symlink changes when $(ARCH) changes.
+ # Detect this and ask user to run make mrproper