[coreboot] suspend/resume in v3

Stefan Reinauer stepan at coresystems.de
Mon Sep 8 18:57:05 CEST 2008


ron minnich wrote:
> On Mon, Sep 8, 2008 at 9:00 AM, Stefan Reinauer <stepan at coresystems.de> wrote:
>
>   
>> roughly:
>> asm volatile ("movl newstack, %eax\n movl %eax, %esp\n")
>>     
>
> and your entire call chain and all automatics on the stack are gone.
> And you can't return from disable_car.
>   
So are you saying it is incredible hard to produce that call chain from
scratch, or copy it over? I really don't think so.

> Moving the stack in the general case won't work. Better to call
> another function -- i.e. disable_car never returns -- that's we do do
> in v2 today.
>   
Works fine for me.

>> We could set up a relocation mapping. That's what FILO does to cope with
>> this issue.
>>
>>     
>
> It seems kind of complex and it is very architecture dependent. 
Yes, as is a bios. We're talking about details in Cache as RAM here,...
that's much CPU specific, whereas the FILO reloc is "only" x86
dependent. Though, all modern CPUs have a mechanism like that, should we
ever try to find out we need that at all.

> If we
> assume there is no return from disable_car, life is very much simpler.
>   
Ok, why don't we do that?


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