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

[Joakim Tjernlund]

Kim Phillips <kim.phillips at freescale.com> wrote on 2010/10/12 21:54:10:
> 
> On Tue, 12 Oct 2010 21:17:38 +0200
> Joakim Tjernlund <joakim.tjernlund at transmode.se> wrote:
> 
> > > Yes, it is a simple symbol to add. I will do it twm if you don't
> > > beat me to it. it would be nice if you could try what works
> > > and not though.
> > 
> > Could not wait, does this work for you?
> > 
> > diff --git a/nand_spl/board/freescale/mpc8313erdb/u-boot.lds 
> > b/nand_spl/board/freescale/mpc8313erdb/u-boot.lds
> > index ad82589..1a3e44f 100644
> > --- a/nand_spl/board/freescale/mpc8313erdb/u-boot.lds
> > +++ b/nand_spl/board/freescale/mpc8313erdb/u-boot.lds
> > @@ -38,6 +38,8 @@ SECTIONS
> >         .data : {
> >                 *(.data*)
> >                 *(.sdata*)
> > +               _GOT_TABLE_ = .;
> > +               *(.got)
> >                 _GOT2_TABLE_ = .;
> >                 *(.got2)
> >                 __got2_entries = (. - _GOT2_TABLE_) >> 2;
> 
> it passes a build test on the 8313, but applying the same change to the
> 8315 still fails to build with bootstrap too big errors, because it
> still suffers from the extra bits.  At least now it's buildable, so
> we have some size info for the curious:
> 
> before (fits):
> 
> $ size ./nand_spl/board/freescale/mpc8315erdb/start.o
>    text      data       bss       dec       hex   filename
>    1528        12         0      1540       604 
./nand_spl/board/freescale/
> mpc8315erdb/start.o
> 
> after (too big):
> 
> $ size ./nand_spl/board/freescale/mpc8315erdb/start.o
>    text      data       bss       dec       hex   filename
>    1588        20         0      1608       648 
./nand_spl/board/freescale/
> mpc8315erdb/start.o

Some sizes:

with -fPIC
size ../u-boot-spl
   text    data     bss     dec     hex filename
   3980      36       0    4016     fb0 ../u-boot-spl

with -mbss-plt -fpic -msingle-pic-base
size ../u-boot-spl
   text    data     bss     dec     hex filename
   3928       0       0    3928     f58 ../u-boot-spl

with -mbss-plt -fpic
size ../u-boot-spl
   text    data     bss     dec     hex filename
   3960       0       0    3960     f78 ../u-boot-spl