Linux-RISC-V Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: Sean Anderson <seanga2@gmail.com>
To: Drew Fustini <pdp7pdp7@gmail.com>,
	"linux-riscv@lists.infradead.org"
	<linux-riscv@lists.infradead.org>,
	Atish Patra <atish.patra@wdc.com>,
	Anup Patel <anup.patel@wdc.com>,
	Damien Le Moal <Damien.LeMoal@wdc.com>,
	Carlos Eduardo de Paula <me@carlosedp.com>
Subject: Re: Kendryte K210: state of MMU support?
Date: Sun, 28 Jun 2020 15:56:12 -0400	[thread overview]
Message-ID: <25d7abde-b3a5-4488-ea93-e0aca9e0693f@gmail.com> (raw)
In-Reply-To: <CAEf4M_BK29oDh94-j3+nixqfPi_r=13Svs4xOUCh_oYjPUg+pg@mail.gmail.com>

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


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

      reply	other threads:[~2020-06-28 19:56 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-28 15:54 Kendryte K210: state of MMU support? Drew Fustini
2020-06-28 19:56 ` Sean Anderson [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=25d7abde-b3a5-4488-ea93-e0aca9e0693f@gmail.com \
    --to=seanga2@gmail.com \
    --cc=Damien.LeMoal@wdc.com \
    --cc=anup.patel@wdc.com \
    --cc=atish.patra@wdc.com \
    --cc=linux-riscv@lists.infradead.org \
    --cc=me@carlosedp.com \
    --cc=pdp7pdp7@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox