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- From b14784e7883390c20ed3ff904892255404a5914b Mon Sep 17 00:00:00 2001
- From: Felix Fietkau <nbd@nbd.name>
- Date: Fri, 7 Jul 2017 17:05:53 +0200
- Subject: add an optional config option for stripping all unnecessary symbol exports from the kernel image
- lede-commit: bb5a40c64b7c4f4848509fa0a6625055fc9e66cc
- Signed-off-by: Felix Fietkau <nbd@nbd.name>
- ---
- include/asm-generic/vmlinux.lds.h | 18 +++++++++++++++---
- include/linux/export.h | 9 ++++++++-
- scripts/Makefile.build | 2 +-
- 3 files changed, 24 insertions(+), 5 deletions(-)
- --- a/include/asm-generic/vmlinux.lds.h
- +++ b/include/asm-generic/vmlinux.lds.h
- @@ -54,6 +54,16 @@
- #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
- +
- #include <linux/export.h>
-
- /* Align . to a 8 byte boundary equals to maximum function alignment. */
- @@ -342,14 +352,14 @@
- /* 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) = .; \
- } \
- \
- @@ -411,7 +421,7 @@
- \
- /* Kernel symbol table: strings */ \
- __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
- - *(__ksymtab_strings) \
- + *(__ksymtab_strings+*) \
- } \
- \
- /* __*init sections */ \
- @@ -799,6 +809,8 @@
- EXIT_TEXT \
- EXIT_DATA \
- EXIT_CALL \
- + SYMTAB_DISCARD \
- + SYMTAB_DISCARD_GPL \
- *(.discard) \
- *(.discard.*) \
- }
- --- a/include/linux/export.h
- +++ b/include/linux/export.h
- @@ -60,12 +60,19 @@ 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))) \
- = VMLINUX_SYMBOL_STR(sym); \
- static const struct kernel_symbol __ksymtab_##sym \
- __used \
- --- a/scripts/Makefile.build
- +++ b/scripts/Makefile.build
- @@ -432,7 +432,7 @@ targets += $(extra-y) $(MAKECMDGOALS) $(
- # Linker scripts preprocessor (.lds.S -> .lds)
- # ---------------------------------------------------------------------------
- quiet_cmd_cpp_lds_S = LDS $@
- - cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
- + cmd_cpp_lds_S = $(CPP) $(EXTRA_LDSFLAGS) $(cpp_flags) -P -U$(ARCH) \
- -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
-
- $(obj)/%.lds: $(src)/%.lds.S FORCE
|
