From 8933b918cd6bce2db5a6a5a51513b62672f13069 Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@openwrt.org>
Date: Sat, 26 Jan 2013 16:26:13 +0000
Subject: kernel: use -ffunction-sections, -fdata-sections and --gc-sections on
 mips

in combination with kernel symbol export stripping this significantly reduces
the kernel image size

SVN-Revision: 35320
---
 .../generic/patches-3.8/221-module_exports.patch   | 88 ++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 target/linux/generic/patches-3.8/221-module_exports.patch

(limited to 'target/linux/generic/patches-3.8/221-module_exports.patch')

diff --git a/target/linux/generic/patches-3.8/221-module_exports.patch b/target/linux/generic/patches-3.8/221-module_exports.patch
new file mode 100644
index 0000000000..da08de626a
--- /dev/null
+++ b/target/linux/generic/patches-3.8/221-module_exports.patch
@@ -0,0 +1,88 @@
+--- a/include/asm-generic/vmlinux.lds.h
++++ b/include/asm-generic/vmlinux.lds.h
+@@ -52,6 +52,16 @@
+ #define LOAD_OFFSET 0
+ #endif
+ 
++#ifndef SYMTAB_KEEP
++#define SYMTAB_KEEP KEEP(*(SORT(___ksymtab+*)))
++#define SYMTAB_KEEP_GPL KEEP(*(SORT(___ksymtab_gpl+*)))
++#endif
++
++#ifndef SYMTAB_DISCARD
++#define SYMTAB_DISCARD
++#define SYMTAB_DISCARD_GPL
++#endif
++
+ #ifndef SYMBOL_PREFIX
+ #define VMLINUX_SYMBOL(sym) sym
+ #else
+@@ -277,14 +287,14 @@
+ 	/* Kernel symbol table: Normal symbols */			\
+ 	__ksymtab         : AT(ADDR(__ksymtab) - LOAD_OFFSET) {		\
+ 		VMLINUX_SYMBOL(__start___ksymtab) = .;			\
+-		KEEP(*(SORT(___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) = .;		\
+-		KEEP(*(SORT(___ksymtab_gpl+*)))				\
++		SYMTAB_KEEP_GPL						\
+ 		VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .;		\
+ 	}								\
+ 									\
+@@ -346,7 +356,7 @@
+ 									\
+ 	/* Kernel symbol table: strings */				\
+         __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
+-		*(__ksymtab_strings)					\
++		*(__ksymtab_strings+*)					\
+ 	}								\
+ 									\
+ 	/* __*init sections */						\
+@@ -680,6 +690,8 @@
+ 	EXIT_TEXT							\
+ 	EXIT_DATA							\
+ 	EXIT_CALL							\
++	SYMTAB_DISCARD							\
++	SYMTAB_DISCARD_GPL						\
+ 	*(.discard)							\
+ 	*(.discard.*)							\
+ 	}
+--- a/scripts/Makefile.build
++++ b/scripts/Makefile.build
+@@ -348,7 +348,7 @@ targets += $(extra-y) $(MAKECMDGOALS) $(
+ # Linker scripts preprocessor (.lds.S -> .lds)
+ # ---------------------------------------------------------------------------
+ quiet_cmd_cpp_lds_S = LDS     $@
+-      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
++      cmd_cpp_lds_S = $(CPP) $(EXTRA_LDSFLAGS) $(cpp_flags) -P -C -U$(ARCH) \
+ 	                     -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
+ 
+ $(obj)/%.lds: $(src)/%.lds.S FORCE
+--- a/include/linux/export.h
++++ b/include/linux/export.h
+@@ -45,12 +45,19 @@ extern struct module __this_module;
+ #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							\
-- 
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