merge .text.*/.rel.text.* sections in module build with -ffunction-section

From: matthieu castet
Date: Sat Feb 27 2010 - 13:07:41 EST


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 ! /*
* 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) }
}