Hi Helmut,
On Wed, 02 Jul 2014 09:04:46 +0200, Helmut Raiger helmut.raiger@hale.at wrote:
Hi,
Hi,
the commit 41623c91 breaks the SPL on i.mx31 platforms.The original startup code (start.S) was position independent to allow relocation in board_init_f. This is necessary as the internal RAM used by the IPL to load the first 2kB from NAND is also used by the NAND controller to buffer pages. As far as the issue goes: where and how exactly is the code not position independent now?
The first statement is now:
ldr pc, _reset_reset: .word reset
reset is an address generated by the linker (here 0x87dc0060). Originally this was:
b resetwhich is a relative branch (here 0x60 bytes forward).
I have to add, that changing this back does not fix the issue, something else is in disorder. I'm still working on it.
Does changing the startup code back to PIC generate any drawbacks on other ARM platforms?
How would this changing back to PIC be implemented? Not by reverting the patch, I hope.
No, it will only be a minor change, I think, but I thought there might have been an additional intention behind the change to position dependent code. One could link the first part to 0xB8000000 (the original position of the SPL when loaded by the IPL) and the part after the relocation to CONFIG_SPL_TEXT_BASE.
What was the intention of the change besides unifying?
Any other intent would be stated in the commit message.
Ok, so the PIC issue was just an oversight.
Maybe Albert, Stefano or Magnus could help? I don't have mx31 hardware either.
It seems we are the only ones still dealing with this old lad ;-)
Full position independence was a lucky side effect of the code, not an intended feature; relocation is precisely here because moving code around usually won't work.
However, no relocation record (relative or other) are generated for the indirect vectors, so that'll need a fix as well. It basically works in U-Boot because most of the targets get loaded at their link-time base address, so the indirect vectors are correct.
I suspect in your case, SPL was linked for one address and gets jumped into at another address.
Can you tell me which board exactly you are experiencing the issue on?
Helmut
Amicalement,