2022-10-18 20:26:34 +00:00
|
|
|
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
|
|
|
|
@@ -81,6 +81,16 @@
|
|
|
|
#define RO_EXCEPTION_TABLE
|
|
|
|
#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)
|
|
|
|
|
2023-05-22 16:07:13 +00:00
|
|
|
@@ -512,14 +522,14 @@
|
2022-10-18 20:26:34 +00:00
|
|
|
/* 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 = .; \
|
|
|
|
} \
|
|
|
|
\
|
2023-05-22 16:07:13 +00:00
|
|
|
@@ -539,7 +549,7 @@
|
2022-10-18 20:26:34 +00:00
|
|
|
\
|
|
|
|
/* Kernel symbol table: strings */ \
|
|
|
|
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
|
|
|
|
- *(__ksymtab_strings) \
|
|
|
|
+ *(__ksymtab_strings+*) \
|
|
|
|
} \
|
|
|
|
\
|
|
|
|
/* __*init sections */ \
|
2023-05-22 16:07:13 +00:00
|
|
|
@@ -1048,6 +1058,8 @@
|
2022-10-18 20:26:34 +00:00
|
|
|
#define COMMON_DISCARDS \
|
|
|
|
SANITIZER_DISCARDS \
|
2022-10-18 21:43:43 +00:00
|
|
|
PATCHABLE_DISCARDS \
|
2022-10-18 20:26:34 +00:00
|
|
|
+ SYMTAB_DISCARD \
|
|
|
|
+ SYMTAB_DISCARD_GPL \
|
|
|
|
*(.discard) \
|
|
|
|
*(.discard.*) \
|
|
|
|
*(.modinfo) \
|
|
|
|
--- a/include/linux/export.h
|
|
|
|
+++ b/include/linux/export.h
|
2023-05-22 16:07:13 +00:00
|
|
|
@@ -72,6 +72,12 @@ struct kernel_symbol {
|
2022-10-18 20:26:34 +00:00
|
|
|
|
|
|
|
#else
|
|
|
|
|
|
|
|
+#ifdef MODULE
|
|
|
|
+#define __EXPORT_SUFFIX(sym)
|
|
|
|
+#else
|
|
|
|
+#define __EXPORT_SUFFIX(sym) "+" #sym
|
|
|
|
+#endif
|
|
|
|
+
|
|
|
|
/*
|
|
|
|
* For every exported symbol, do the following:
|
|
|
|
*
|
2023-05-22 16:07:13 +00:00
|
|
|
@@ -87,7 +93,7 @@ struct kernel_symbol {
|
2022-10-18 21:43:43 +00:00
|
|
|
extern typeof(sym) sym; \
|
2022-10-18 20:26:34 +00:00
|
|
|
extern const char __kstrtab_##sym[]; \
|
|
|
|
extern const char __kstrtabns_##sym[]; \
|
|
|
|
- asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \
|
|
|
|
+ asm(" .section \"__ksymtab_strings" __EXPORT_SUFFIX(sym) "\",\"aMS\",%progbits,1 \n" \
|
|
|
|
"__kstrtab_" #sym ": \n" \
|
|
|
|
" .asciz \"" #sym "\" \n" \
|
|
|
|
"__kstrtabns_" #sym ": \n" \
|
|
|
|
--- a/include/asm-generic/export.h
|
|
|
|
+++ b/include/asm-generic/export.h
|
2023-05-22 16:07:13 +00:00
|
|
|
@@ -31,6 +31,12 @@
|
2022-10-18 20:26:34 +00:00
|
|
|
#endif
|
|
|
|
.endm
|
|
|
|
|
|
|
|
+#ifdef MODULE
|
|
|
|
+#define __EXPORT_SUFFIX(name)
|
|
|
|
+#else
|
|
|
|
+#define __EXPORT_SUFFIX(name) + #name
|
|
|
|
+#endif
|
|
|
|
+
|
|
|
|
/*
|
|
|
|
* note on .section use: we specify progbits since usage of the "M" (SHF_MERGE)
|
|
|
|
* section flag requires it. Use '%progbits' instead of '@progbits' since the
|
2023-05-22 16:07:13 +00:00
|
|
|
@@ -44,7 +50,7 @@
|
2022-10-18 20:26:34 +00:00
|
|
|
__ksymtab_\name:
|
|
|
|
__put \val, __kstrtab_\name
|
|
|
|
.previous
|
|
|
|
- .section __ksymtab_strings,"aMS",%progbits,1
|
|
|
|
+ .section __ksymtab_strings __EXPORT_SUFFIX(name),"aMS",%progbits,1
|
|
|
|
__kstrtab_\name:
|
|
|
|
.asciz "\name"
|
|
|
|
.previous
|
|
|
|
--- a/scripts/Makefile.build
|
|
|
|
+++ b/scripts/Makefile.build
|
2023-05-22 16:07:13 +00:00
|
|
|
@@ -388,7 +388,7 @@ targets += $(real-dtb-y) $(lib-y) $(alwa
|
2022-10-18 20:26:34 +00:00
|
|
|
# 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
|