[U-Boot] [PATCH] mpc83xx: Add -fpic relocation support

[Albert ARIBAUD]

Le 12/10/2010 19:11, Joakim Tjernlund a écrit :

> Figured I should mention that I have added -msingle-pic-base(from ARM)
> which
> works nicely with -fpic(not sure if -fPIC is possible) and reduces size
> even more:

Since you seem to be following the same path as I did on ARM, I may as 
well ask: did you try removing -fPIC and -msingle-pic-base from compile 
options and adding -pie to the link options instead?

Link option -pie generates ELF relocation and, on ARM at least, does a 
better job than GOT reloc, which does not fix handle pointers in 
initialized data while ELF reloc fixes them.

And since ELF reloc does not modify code (it is a linker option), you 
end up with the same size for text+data+rodata. You do have a bigger 
FLASH image though, because the ELF reloc tables are bigger than the GOT 
table; but you can git rid of them / not copy them to RAM once relocated.

The move from -fPIC to ELF on ARM can be looked for in the elf_reloc 
branch of the u-boot-arm repo.

Amicalement,
-- 
Albert.