diff options
| -rw-r--r-- | Config.in | 8 | ||||
| -rw-r--r-- | include/kernel-build.mk | 24 | ||||
| -rw-r--r-- | include/kernel-defaults.mk | 5 | ||||
| -rw-r--r-- | target/linux/generic-2.6/patches-2.6.28/027-module_exports.patch | 117 | ||||
| -rw-r--r-- | target/linux/generic-2.6/patches-2.6.30/028-module_exports.patch | 117 |
5 files changed, 270 insertions, 1 deletions
@@ -134,6 +134,14 @@ config USE_MKLIBS 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 diff --git a/include/kernel-build.mk b/include/kernel-build.mk index d48f8b9..e3e446b 100644 --- a/include/kernel-build.mk +++ b/include/kernel-build.mk @@ -54,6 +54,28 @@ define BuildKernel $(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 $$@ @@ -62,7 +84,7 @@ define BuildKernel $(Kernel/CompileModules) touch $$@ - $(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 $$@ diff --git a/include/kernel-defaults.mk b/include/kernel-defaults.mk index f205553..0ba1e05 100644 --- a/include/kernel-defaults.mk +++ b/include/kernel-defaults.mk @@ -22,6 +22,11 @@ KERNEL_MAKEOPTS := -C $(LINUX_DIR) \ KBUILD_HAVE_NLS=no \ CONFIG_SHELL="$(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)) 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 0000000..2a44832 --- /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 0000000..ec037b3 --- /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 |