Re: [PATCH v4 5/5] RISC-V: Add crash kernel support

[Nick Kossifidis]

Hello Geert,

Στις 2021-06-15 16:19, Geert Uytterhoeven έγραψε:
> This does not match
> https://github.com/devicetree-org/dt-schema/blob/master/schemas/chosen.yaml#L77:
>
>     $ref: types.yaml#/definitions/uint64-array
>     maxItems: 2
>     description:
>       This property (currently used only on arm64) holds the memory 
> range,
>       the address and the size, of the elf core header which mainly 
> describes
>       the panicked kernel\'s memory layout as PT_LOAD segments of elf 
> format.
>
> Hence "linux,elfcorehdr" should be a property of the /chosen node,
> instead of a memory node with a compatible value of "linux,elfcorehdr".

That's a binding for a property on the /chosen node, that as the text 
says it's defined for arm64 only and the code that handled it was also 
on arm64. Instead the reserved-region binding I used is a standard 
binding, if you don't like the name used for the compatible string 
because it overlaps with that property we can change it. I want to use a 
reserved-region for this because we'll have to reserve it anyway so 
using a property on /chosen and then using that property to reserve the 
region seemed suboptimal.

> > v2:
> >  * Use linux,usable-memory on /memory instead of a new binding
>
> This part seems to have been removed in v3 and later?
> Note that "linux,usable-memory-range" should be a property of the
> /chosen node, too, cfr.
> https://github.com/devicetree-org/dt-schema/blob/master/schemas/chosen.yaml#L85

No special handling is needed when using linux,usable-memory on /memory, 
limiting the available memory is handled by generic code at 
drivers/of/fdt.c

Regards,
Nick