Kendryte K210: state of MMU support?

Kendryte K210: state of MMU support?

[Drew Fustini]

Hello - as far as I know, the MMU in the K210 is still not supported by Linux.

Anyone know of progress that has been made?

Thanks,
Drew

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Re: Kendryte K210: state of MMU support?

[Sean Anderson]

On 6/28/20 11:54 AM, Drew Fustini wrote:
> Hello - as far as I know, the MMU in the K210 is still not supported by Linux.
> 
> Anyone know of progress that has been made?
> 
> Thanks,
> Drew
> 

AFAIK support for the MMU is not planned, since it follows an older
version of the privilege-mode specs. For discussion, see [1], [2].

The CSRs to configure the MMU on the K210 can only be accessed via
M-mode, so the existing boot-chain with OpenSBI before Linux would not
work. In addition, as discussed in [1], there are some ties between
M-mode Linux and NOMMU on riscv. Aside from that, the only other major
differences are in the layout of some CSRs.

--Sean

[1] https://lore.kernel.org/linux-riscv/mhng-a9c74759-ab94-4270-a993-9df380811220@palmerdabbelt-glaptop1/T/#m56d9c49c53b104e282106005bf6d289cad4970a3
[2] https://lore.kernel.org/linux-riscv/20200312051107.1454880-1-damien.lemoal@wdc.com/T/#m137c2c073481f21207c92633550e6465ffc1c550


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