[U-Boot-Users] fixup section problem.

Txema Lopez
2006-11-02T09:21:07Z

Hi,

We are working in a MPC5200B based custom board and we are developping a
tool to relocate a U-Boot (1.1.4 version) binary file to a different
address in flash that it was linked. So, we have to change the GOT and
FIXUP entries in the original file to point at the new address. Doing
this work, we have found that, surprisingly, the FIXUP section in U-Boot
is empty. When U-Boot is relocated from flash to sdram these lines in
the file start.S have no effect:
/*
* Now adjust the fixups and the pointers to the fixups
* in case we need to move ourselves again.
*/
2: li r0,__fixup_entries at sectoff@l
lwz r3,GOT(_FIXUP_TABLE_)
cmpwi r0,0
mtctr r0
addi r3,r3,-4
beq 4f
3: lwzu r4,4(r3)
lwzux r0,r4,r11
add r0,r0,r11
stw r10,0(r3)
stw r0,0(r4)
bdnz 3b
4:
Looking into the sources we have found some places where the fixup
elements seem to be relocated manually, i.e.:
void malloc_bin_reloc (void)
{
DECLARE_GLOBAL_DATA_PTR;

unsigned long *p = (unsigned long *)(&av_[2]);
int i;

for (i=2; i<(sizeof(av_)/sizeof(mbinptr)); ++i) {
*p++ += gd->reloc_off;
}
}
Is there any reason to leave the FIXUP section empty in U-Boot? Is it a
bug?.

Checking the u-boot.lds file for the IceCube board we have found that
fhe fixup section is included in the TEXT section and in the RELOC
section, but the linker generate code only for the TEXT section. If we
put it only in the RELOC section the FIXUP is not empty, the pointers
adjustement in the start.S seems to work properly and the
malloc_bin_reloc() function would be not necessary. Does anynone know if
I'am missing something?

Any clue will be welcomed.
Best regards,

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