[U-Boot] FPGA relocation/C environment

Joakim Tjernlund
2009-10-29T14:22:24Z

wolfgang at leila.ping.de (Wolfgang Wegner) wrote on 29/10/2009 14:41:00:
>
> Dear Joakim Tjernlund,
>
> On Thu, Oct 29, 2009 at 02:08:05PM +0100, Joakim Tjernlund wrote:
> >
> > Just to avoid any misunderstandings, the GOT does not hold offsets, it holds
> > absolute addresses. These addresses gets adjusted with an offset when you
> > relocate.
>
> thank you, I already understood this.
>
> As far as I can see there is already some GOT handling in cpu/mcf532x/start.S
> and the flags (-fPIC) in cpu/mcf532x/config.mk (and other coldfire ports, but
> MCF532x/MCF537x is what I am currently working on for testing), but somehow
> it does not work.
> However, it takes some time for me to understand the assembler code,
> especially the powerpc counterpart I am using as a reference.
>
> There is a __got_start and __got_end in my u-boot.map, so I would think
> the linker does behave correctly - but I did not yet check if all the
> symbols (better: symbols' addresses) expected to be there are really
> present:
>
> .reloc 0x00024600 0x1990
> 0x00024600 __got_start = .
> *(.got)
> .got 0x00024600 0x1990 cpu/mcf532x/cpu_init.o
> 0x00025f90 __got_end = .
> 0x00025f90 _GOT2_TABLE_ = .
> *(.got2)
> 0x00025f90 _FIXUP_TABLE_ = .
> *(.fixup)
> 0x00000000 __got2_entries = ((_FIXUP_TABLE_ -
> _GOT2_TABLE_) >> 0x2)
> 0x00000000 __fixup_entries = ((. - _FIXUP_TABLE_) >> 0x2)

It seems like you don't have any relocation data as both __got2_entries and
__fixup_entries are zero. Something seems broken in general, perhaps your linker script
is bust?

>
> (flash resides at 0x0, SDRAM at 0x4000000 and CONFIG_SYS_MONITOR_BASE is
> 0x40020000)