[U-Boot] Most ARM CPU's have buggy clear_bss?

[Albert ARIBAUD]

Le 29/10/2010 15:50, Alexander Holler a écrit :
> Am 29.10.2010 15:37, schrieb Albert ARIBAUD:
>> Le 29/10/2010 14:31, Alexander Holler a écrit :
>>
>>>> Hmm... What do you mean by "a non relocated BSS ins't cleared" ? AFAICT,
>>>> the start.S code clears the relocated BSS. Are we in a case where you
>>>> prevent part of the relocation process, such as by using
>>>> CONFIG_SKIP_RELOCATE_UBOOT?
>>>
>>> The (wrong, not relocated) location of nand_chip (building without
>>> -fPIC) is inside the BSS before relocation through staŕt.S. This part of
>>> RAM will not be cleared because it shouldn't be used.
>>
>> Er... nand_chip is declared as static global uninitialized, which makes
>> it normal that it goes to BSS, and also normal that it has no fixups
>> applied, as relocation happens before BSS can be accessed, that is, at a
>> time where BSS is still completely uninitialized. Relocations to BSS
>> just don't make sense, they're done only to constant code (.text and
>> .data) emitted by the compiler/linker.
>>
>> So if you call nand_init to fill nand_chip before relocation, don't
>> expect it to be fixed up during relocation and useable after. That
>> simply is not possible.
>
> nand_init() is called inside board.c after relocation. But the
> relocation does not change the address of that nand_chip. At least this
> is what that printf("nand_chip: %p\n",&nand_chip[0]); inside
> nand_init() tells me.

Can you give specific values, i.e., can you copy-paste the output of 
these printf()s along with the version of the toolchain used, both in a 
"working" and "non-working" case?

>>>> Providing the location on the Net of the toolchains will be enough,
>>>> (along with which version of nand.c you're using if that matters).
>>>
>>> I'm using Gentoo where it's easy to swith the compiler (on a DockStar ~
>>> Sheevaplug = Kirkwood Feroceon 88FR131) to compile the current HEAD of
>>> the master
>>
>> I'm sure it is, but it does not tell me where I can get these toolchains
>> and test them :) (except for the ELDK one which I use routinely).
>
> I assume it's not possible. Gentoo is compiled from source. A minimal
> root containing binaries for binutils and gcc (4.4.x currently I think)
> is available at
>
> http://distfiles.gentoo.org/releases/arm/autobuilds/current-stage3/
>
> Therefore my offer to supply generated nand.s.

Hmm... In that case yes, you could supply it for that toolchain that 
cannot easily be used by others, if not via the list, at least by 
private e-mail.

> Regards,
>
> Alexander

Amicalement,
-- 
Albert.