103 lines
3.2 KiB
Diff
103 lines
3.2 KiB
Diff
From b14784e7883390c20ed3ff904892255404a5914b Mon Sep 17 00:00:00 2001
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From: Felix Fietkau <nbd@nbd.name>
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Date: Fri, 7 Jul 2017 17:05:53 +0200
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Subject: add an optional config option for stripping all unnecessary symbol exports from the kernel image
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lede-commit: bb5a40c64b7c4f4848509fa0a6625055fc9e66cc
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Signed-off-by: Felix Fietkau <nbd@nbd.name>
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---
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include/asm-generic/vmlinux.lds.h | 18 +++++++++++++++---
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include/linux/export.h | 9 ++++++++-
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scripts/Makefile.build | 2 +-
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3 files changed, 24 insertions(+), 5 deletions(-)
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--- a/include/asm-generic/vmlinux.lds.h
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+++ b/include/asm-generic/vmlinux.lds.h
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@@ -81,6 +81,16 @@
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#define RO_EXCEPTION_TABLE
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#endif
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+#ifndef SYMTAB_KEEP
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+#define SYMTAB_KEEP KEEP(*(SORT(___ksymtab+*)))
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+#define SYMTAB_KEEP_GPL KEEP(*(SORT(___ksymtab_gpl+*)))
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+#endif
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+
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+#ifndef SYMTAB_DISCARD
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+#define SYMTAB_DISCARD
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+#define SYMTAB_DISCARD_GPL
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+#endif
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+
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/* Align . to a 8 byte boundary equals to maximum function alignment. */
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#define ALIGN_FUNCTION() . = ALIGN(8)
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@@ -473,14 +483,14 @@
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/* Kernel symbol table: Normal symbols */ \
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__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) { \
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__start___ksymtab = .; \
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- KEEP(*(SORT(___ksymtab+*))) \
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+ SYMTAB_KEEP \
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__stop___ksymtab = .; \
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} \
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\
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/* Kernel symbol table: GPL-only symbols */ \
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__ksymtab_gpl : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) { \
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__start___ksymtab_gpl = .; \
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- KEEP(*(SORT(___ksymtab_gpl+*))) \
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+ SYMTAB_KEEP_GPL \
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__stop___ksymtab_gpl = .; \
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} \
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\
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@@ -542,7 +552,7 @@
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\
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/* Kernel symbol table: strings */ \
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__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
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- *(__ksymtab_strings) \
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+ *(__ksymtab_strings+*) \
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} \
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\
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/* __*init sections */ \
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@@ -1018,6 +1028,8 @@
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#define COMMON_DISCARDS \
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SANITIZER_DISCARDS \
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+ SYMTAB_DISCARD \
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+ SYMTAB_DISCARD_GPL \
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*(.discard) \
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*(.discard.*) \
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*(.modinfo) \
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--- a/include/linux/export.h
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+++ b/include/linux/export.h
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@@ -82,6 +82,12 @@ struct kernel_symbol {
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#else
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+#ifdef MODULE
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+#define __EXPORT_SUFFIX(sym)
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+#else
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+#define __EXPORT_SUFFIX(sym) "+" #sym
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+#endif
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+
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/*
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* For every exported symbol, do the following:
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*
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@@ -99,7 +105,7 @@ struct kernel_symbol {
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extern const char __kstrtab_##sym[]; \
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extern const char __kstrtabns_##sym[]; \
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__CRC_SYMBOL(sym, sec); \
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- asm(" .section \"__ksymtab_strings\",\"aMS\",%progbits,1 \n" \
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+ asm(" .section \"__ksymtab_strings" __EXPORT_SUFFIX(sym) "\",\"aMS\",%progbits,1 \n" \
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"__kstrtab_" #sym ": \n" \
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" .asciz \"" #sym "\" \n" \
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"__kstrtabns_" #sym ": \n" \
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--- a/scripts/Makefile.build
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+++ b/scripts/Makefile.build
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@@ -367,7 +367,7 @@ targets += $(lib-y) $(always-y) $(MAKECM
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# Linker scripts preprocessor (.lds.S -> .lds)
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# ---------------------------------------------------------------------------
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quiet_cmd_cpp_lds_S = LDS $@
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- cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
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+ cmd_cpp_lds_S = $(CPP) $(EXTRA_LDSFLAGS) $(cpp_flags) -P -U$(ARCH) \
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-D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
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$(obj)/%.lds: $(src)/%.lds.S FORCE
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