|
|
|
|
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
|
|
|
|
|
+
|
|
|
|
|
/* Align . to a 8 byte boundary equals to maximum function alignment. */
|
|
|
|
|
#define ALIGN_FUNCTION() . = ALIGN(8)
|
|
|
|
|
|
|
|
|
|
@@ -405,14 +415,14 @@
|
|
|
|
|
/* Kernel symbol table: Normal symbols */ \
|
|
|
|
|
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) { \
|
|
|
|
|
__start___ksymtab = .; \
|
|
|
|
|
- KEEP(*(SORT(___ksymtab+*))) \
|
|
|
|
|
+ SYMTAB_KEEP \
|
|
|
|
|
__stop___ksymtab = .; \
|
|
|
|
|
} \
|
|
|
|
|
\
|
|
|
|
|
/* Kernel symbol table: GPL-only symbols */ \
|
|
|
|
|
__ksymtab_gpl : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) { \
|
|
|
|
|
__start___ksymtab_gpl = .; \
|
|
|
|
|
- KEEP(*(SORT(___ksymtab_gpl+*))) \
|
|
|
|
|
+ SYMTAB_KEEP_GPL \
|
|
|
|
|
__stop___ksymtab_gpl = .; \
|
|
|
|
|
} \
|
|
|
|
|
\
|
|
|
|
|
@@ -474,7 +484,7 @@
|
|
|
|
|
\
|
|
|
|
|
/* Kernel symbol table: strings */ \
|
|
|
|
|
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
|
|
|
|
|
- *(__ksymtab_strings) \
|
|
|
|
|
+ *(__ksymtab_strings+*) \
|
|
|
|
|
} \
|
|
|
|
|
\
|
|
|
|
|
/* __*init sections */ \
|
|
|
|
|
@@ -881,6 +891,8 @@
|
|
|
|
|
EXIT_TEXT \
|
|
|
|
|
EXIT_DATA \
|
|
|
|
|
EXIT_CALL \
|
|
|
|
|
+ SYMTAB_DISCARD \
|
|
|
|
|
+ SYMTAB_DISCARD_GPL \
|
|
|
|
|
*(.discard) \
|
|
|
|
|
*(.discard.*) \
|
|
|
|
|
*(.modinfo) \
|
|
|
|
|
--- a/include/linux/export.h
|
|
|
|
|
+++ b/include/linux/export.h
|
|
|
|
|
@@ -98,18 +98,26 @@ struct kernel_symbol {
|
|
|
|
|
|
|
|
|
|
#else
|
|
|
|
|
|
|
|
|
|
+#ifdef MODULE
|
|
|
|
|
+#define __EXPORT_SUFFIX(sym)
|
|
|
|
|
+#else
|
|
|
|
|
+#define __EXPORT_SUFFIX(sym) "+" #sym
|
|
|
|
|
+#endif
|
|
|
|
|
+
|
|
|
|
|
#define ___export_symbol_common(sym, sec) \
|
|
|
|
|
extern typeof(sym) sym; \
|
|
|
|
|
__CRC_SYMBOL(sym, sec); \
|
|
|
|
|
static const char __kstrtab_##sym[] \
|
|
|
|
|
- __attribute__((section("__ksymtab_strings"), used, aligned(1))) \
|
|
|
|
|
+ __attribute__((section("__ksymtab_strings" \
|
|
|
|
|
+ __EXPORT_SUFFIX(sym)), used, aligned(1))) \
|
|
|
|
|
= #sym \
|
|
|
|
|
|
|
|
|
|
/* For every exported symbol, place a struct in the __ksymtab section */
|
|
|
|
|
#define ___EXPORT_SYMBOL_NS(sym, sec, ns) \
|
|
|
|
|
___export_symbol_common(sym, sec); \
|
|
|
|
|
static const char __kstrtabns_##sym[] \
|
|
|
|
|
- __attribute__((section("__ksymtab_strings"), used, aligned(1))) \
|
|
|
|
|
+ __attribute__((section("__ksymtab_strings" \
|
|
|
|
|
+ __EXPORT_SUFFIX(sym)), used, aligned(1))) \
|
|
|
|
|
= #ns; \
|
|
|
|
|
__KSYMTAB_ENTRY_NS(sym, sec)
|
|
|
|
|
|
|
|
|
|
--- a/scripts/Makefile.build
|
|
|
|
|
+++ b/scripts/Makefile.build
|
|
|
|
|
@@ -353,7 +353,7 @@ 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
|
