MIPS RELOCATABLE: [PATCH 14/20] RISC-V: erizo: migrate to PBL

[Ahmad Fatoum]

Hi,

On 15.03.21 16:37, Antony Pavlov wrote:
> On Mon, 15 Mar 2021 13:40:10 +0100
> Ahmad Fatoum <a.fatoum at pengutronix.de> wrote:
>> Without having dug into the MIPS code, the main point of CONFIG_RELOCATABLE
>> is that PBL can check for it to decide where to copy barebox proper to.
>>
>> This is very relevant if there's no TEXT_BASE that works for all boards
>> that you need to support with your multi-image barebox.
> 
> So CONFIG_RELOCATABLE can be very helpful.
> 
> At the moment MIPS barebox is always relocatable.
> Sometimes it's useful to run barebox from fixed TEXT_BASE (e.g. during gdb debug session),
> so this fixed TEXT_BASE behaviour can be introduced for CONFIG_RELOCATABLE=n case.

With the pbl break stuff, you could in theory already flip a config option
and have a gdb script that computes your load address from the address of
your breakpoint. That would be nice to have as a ready-to-use script.

I recall Oleksij and Michael did something in that regard.

Benefit is that the break is an actual machine code nop when inactive,
so binary size/layout shouldn't change, unlike with flipping CONFIG_RELOCATABLE.
For RISC-V, I see no good reason to allow CONFIG_RELOCATABLE=n right now.

Cheers,
Ahmad

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