[PATCH 2/4] module: Sort exported symbols

From: Alessio Igor Bogani
Date: Fri Apr 15 2011 - 11:26:06 EST


This patch places every exported symbol in its own section
(i.e. "___ksymtab__printk"). Thus the linker will use its SORT() directive
to sort and finally merge all symbol in the right and final section
(i.e. "__ksymtab").

This work was supported by a hardware donation from the CE Linux Forum.

Signed-off-by: Alessio Igor Bogani <abogani@xxxxxxxxxx>
---
include/asm-generic/vmlinux.lds.h | 20 ++++++++++----------
include/linux/module.h | 4 ++--
scripts/module-common.lds | 11 +++++++++++
3 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index bd297a2..349e356 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -274,70 +274,70 @@
/* Kernel symbol table: Normal symbols */ \
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab) = .; \
- *(__ksymtab) \
+ *(SORT(___ksymtab__*)) \
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) \
+ *(SORT(___ksymtab_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) \
+ *(SORT(___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) \
+ *(SORT(___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) \
+ *(SORT(___ksymtab_gpl_future__*)) \
VMLINUX_SYMBOL(__stop___ksymtab_gpl_future) = .; \
} \
\
/* Kernel symbol table: Normal symbols */ \
__kcrctab : AT(ADDR(__kcrctab) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab) = .; \
- *(__kcrctab) \
+ *(SORT(___kcrctab__*)) \
VMLINUX_SYMBOL(__stop___kcrctab) = .; \
} \
\
/* Kernel symbol table: GPL-only symbols */ \
__kcrctab_gpl : AT(ADDR(__kcrctab_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_gpl) = .; \
- *(__kcrctab_gpl) \
+ *(SORT(___kcrctab_gpl__*)) \
VMLINUX_SYMBOL(__stop___kcrctab_gpl) = .; \
} \
\
/* Kernel symbol table: Normal unused symbols */ \
__kcrctab_unused : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_unused) = .; \
- *(__kcrctab_unused) \
+ *(SORT(___kcrctab_unused__*)) \
VMLINUX_SYMBOL(__stop___kcrctab_unused) = .; \
} \
\
/* Kernel symbol table: GPL-only unused symbols */ \
__kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_unused_gpl) = .; \
- *(__kcrctab_unused_gpl) \
+ *(SORT(___kcrctab_unused_gpl__*)) \
VMLINUX_SYMBOL(__stop___kcrctab_unused_gpl) = .; \
} \
\
/* Kernel symbol table: GPL-future-only symbols */ \
__kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_gpl_future) = .; \
- *(__kcrctab_gpl_future) \
+ *(SORT(___kcrctab_gpl_future__*)) \
VMLINUX_SYMBOL(__stop___kcrctab_gpl_future) = .; \
} \
\
diff --git a/include/linux/module.h b/include/linux/module.h
index b62f0a2..853f566 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -223,7 +223,7 @@ struct module_use {
extern void *__crc_##sym __attribute__((weak)); \
static const unsigned long __kcrctab_##sym \
__used \
- __attribute__((section("__kcrctab" sec), unused)) \
+ __attribute__((section("___kcrctab" sec "__"#sym), unused)) \
= (unsigned long) &__crc_##sym;
#else
#define __CRC_SYMBOL(sym, sec)
@@ -238,7 +238,7 @@ struct module_use {
= MODULE_SYMBOL_PREFIX #sym; \
static const struct kernel_symbol __ksymtab_##sym \
__used \
- __attribute__((section("__ksymtab" sec), unused)) \
+ __attribute__((section("___ksymtab" sec "__"#sym), unused)) \
= { (unsigned long)&sym, __kstrtab_##sym }

#define EXPORT_SYMBOL(sym) \
diff --git a/scripts/module-common.lds b/scripts/module-common.lds
index 47a1f9a..055a8d5 100644
--- a/scripts/module-common.lds
+++ b/scripts/module-common.lds
@@ -5,4 +5,15 @@
*/
SECTIONS {
/DISCARD/ : { *(.discard) }
+
+ __ksymtab : { *(SORT(___ksymtab__*)) }
+ __ksymtab_gpl : { *(SORT(___ksymtab_gpl__*)) }
+ __ksymtab_unused : { *(SORT(___ksymtab_unused__*)) }
+ __ksymtab_unused_gpl : { *(SORT(___ksymtab_unused_gpl__*)) }
+ __ksymtab_gpl_future : { *(SORT(___ksymtab_gpl_future__*)) }
+ __kcrctab : { *(SORT(___kcrctab__*)) }
+ __kcrctab_gpl : { *(SORT(___kcrctab_gpl__*)) }
+ __kcrctab_unused : { *(SORT(___kcrctab_unused__*)) }
+ __kcrctab_unused_gpl : { *(SORT(___kcrctab_unused_gpl__*)) }
+ __kcrctab_gpl_future : { *(SORT(___kcrctab_gpl_future__*)) }
}
--
1.7.0.4

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