From: matthieu castet <castet.matthieu@free.fr>
To: linux-mips@linux-mips.org,
Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: merge .text.*/.rel.text.* sections in module build with -ffunction-section
Date: Sat, 27 Feb 2010 18:57:30 +0100 [thread overview]
Message-ID: <4B895D0A.1090401@free.fr> (raw)
[-- Attachment #1: Type: text/plain, Size: 874 bytes --]
Hi,
mips (and other arch) use -ffunction-section (I am not sure why. It may be to prevent gcc to emit bad relocation).
Apart from making the code a bit bigger it :
- make very difficult to analyze binary kernel dump (without symbol) of module : you can't easily knowing the load address of the module find the symbol of an address.
- make module bigger (due to alignment between section and bigger section table)
- make the module loading slower (more section to parse)
I wondering why we doesn't merge all text section in one section when building .ko.
This can be done with :
mipsel-openwrt-linux-uclibc-ld -r -m elf32ltsmip -o vfat2.ko vfat.ko -T module-common.lds
Why doesn't mips provide a custom module-common.lds that does that ?
Matthieu
PS : could you keep me in CC
PS2 :
ls -l vfat2.ko vfat.ko
12881 vfat2.ko
14748 vfat.ko
we save 13% of module size !
[-- Attachment #2: module-common.lds --]
[-- Type: text/plain, Size: 272 bytes --]
/*
* Common module linker script, always used when linking a module.
* Archs are free to supply their own linker scripts. ld will
* combine them automatically.
*/
SECTIONS {
.text : {
*(.text.*)
}
.rel.text : {
*(.rel.text.*)
}
/DISCARD/ : { *(.discard) }
}
reply other threads:[~2010-02-27 17:57 UTC|newest]
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