Note that this will make the system libraries incompatible with most of the packages
that are not selected during the build process
+config STRIP_KERNEL_EXPORTS
+ depends LINUX_2_6
+ bool "Strip unnecessary exports from the kernel image"
+ help
+ Reduces kernel size by stripping unused kernel exports from the kernel image
+ Note that this might make the kernel incompatible with any kernel modules that
+ were not selected at the time the kernel image was created
+
comment "Package build options"
config DEBUG
$(Kernel/Prepare)
touch $$@
+ $(KERNEL_BUILD_DIR)/symtab.txt: FORCE
+ find $(LINUX_DIR) $(STAGING_DIR_ROOT)/lib/modules -name \*.ko | \
+ xargs $(TARGET_CROSS)nm | \
+ awk '$$$$1 == "U" { print $$$$2 } ' | \
+ sort -u > $$@
+
+ $(KERNEL_BUILD_DIR)/symtab.h: $(KERNEL_BUILD_DIR)/symtab.txt
+ ( \
+ echo '#define SYMTAB_KEEP \'; \
+ cat $(KERNEL_BUILD_DIR)/symtab.txt | \
+ awk '{print "*(__ksymtab." $$$$1 ") \\" }'; \
+ echo; \
+ echo '#define SYMTAB_KEEP_GPL \'; \
+ cat $(KERNEL_BUILD_DIR)/symtab.txt | \
+ awk '{print "*(__ksymtab_gpl." $$$$1 ") \\" }'; \
+ echo; \
+ echo '#define SYMTAB_KEEP_STR \'; \
+ cat $(KERNEL_BUILD_DIR)/symtab.txt | \
+ awk '{print "*(__ksymtab_strings." $$$$1 ") \\" }'; \
+ echo; \
+ ) > $$@
+
$(STAMP_CONFIGURED): $(STAMP_PREPARED) $(LINUX_CONFIG) $(GENERIC_LINUX_CONFIG) $(TOPDIR)/.config
$(Kernel/Configure)
touch $$@
$(Kernel/CompileModules)
touch $$@
- $(LINUX_DIR)/.image: $(STAMP_CONFIGURED) FORCE
+ $(LINUX_DIR)/.image: $(STAMP_CONFIGURED) $(if $(CONFIG_STRIP_KERNEL_EXPORTS),$(KERNEL_BUILD_DIR)/symtab.h) FORCE
$(Kernel/CompileImage)
touch $$@
KBUILD_HAVE_NLS=no \
CONFIG_SHELL="$(BASH)"
+ifdef CONFIG_STRIP_KERNEL_EXPORTS
+ KERNEL_MAKEOPTS += \
+ EXTRA_LDSFLAGS="-I$(KERNEL_BUILD_DIR) -include symtab.h"
+endif
+
INITRAMFS_EXTRA_FILES ?= $(GENERIC_PLATFORM_DIR)/image/initramfs-base-files.txt
ifneq (,$(KERNEL_CC))
--- /dev/null
+--- 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) \
--- /dev/null
+--- 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
projects / openwrt / openwrt.git / commitdiff