[RFT 1/2] RISC-V: handle missing "no-map" properties for OpenSBI's PMP protected regions

[Prabhakar Mahadev Lad]

Hi Palmer,

> -----Original Message-----
> From: Palmer Dabbelt <palmer at dabbelt.com>
> Sent: Tuesday, December 19, 2023 6:07 PM
> To: Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj at bp.renesas.com>
> Cc: Conor Dooley <conor at kernel.org>; Conor Dooley <conor.dooley at microchip.com>;
> prabhakar.csengg at gmail.com; geert+renesas at glider.be; Atish Patra <atishp at rivosinc.com>; Paul Walmsley
> <paul.walmsley at sifive.com>; apatel at ventanamicro.com; alexghiti at rivosinc.com; Bjorn Topel
> <bjorn at rivosinc.com>; suagrfillet at gmail.com; jeeheng.sia at starfivetech.com;
> petrtesarik at huaweicloud.com; linux-riscv at lists.infradead.org; linux-kernel at vger.kernel.org;
> stable at vger.kernel.org
> Subject: RE: [RFT 1/2] RISC-V: handle missing "no-map" properties for OpenSBI's PMP protected regions
> 
> On Tue, 19 Dec 2023 09:27:42 PST (-0800), prabhakar.mahadev-lad.rj at bp.renesas.com wrote:
> > Hi Conor,
> >
> >> -----Original Message-----
> >> From: Conor Dooley <conor at kernel.org>
> >> Sent: Tuesday, December 19, 2023 5:18 PM
> >> To: Conor Dooley <conor.dooley at microchip.com>
> >> Cc: Lad, Prabhakar <prabhakar.csengg at gmail.com>; Palmer Dabbelt
> >> <palmer at dabbelt.com>;
> >> geert+renesas at glider.be; Atish Patra <atishp at rivosinc.com>; Paul
> >> geert+Walmsley <paul.walmsley at sifive.com>;
> >> apatel at ventanamicro.com; alexghiti at rivosinc.com; Bjorn Topel
> >> <bjorn at rivosinc.com>; suagrfillet at gmail.com;
> >> jeeheng.sia at starfivetech.com; petrtesarik at huaweicloud.com; linux-
> >> riscv at lists.infradead.org; linux-kernel at vger.kernel.org;
> >> stable at vger.kernel.org; Prabhakar Mahadev Lad
> >> <prabhakar.mahadev-lad.rj at bp.renesas.com>
> >> Subject: Re: [RFT 1/2] RISC-V: handle missing "no-map" properties for
> >> OpenSBI's PMP protected regions
> >>
> >> Hey,
> >>
> >> On Thu, Dec 07, 2023 at 01:11:23PM +0000, Conor Dooley wrote:
> >> > On Thu, Dec 07, 2023 at 01:02:00PM +0000, Lad, Prabhakar wrote:
> >> > > On Wed, Dec 6, 2023 at 2:26 PM Conor Dooley <conor at kernel.org> wrote:
> >> > > > On Wed, Dec 06, 2023 at 04:52:11AM -0800, Palmer Dabbelt wrote:
> >> > > > > On Thu, 10 Aug 2023 02:07:10 PDT (-0700), Conor Dooley wrote:
> >> >
> >> > > > > > I'm perfectly happy to drop this series though, if people
> >> > > > > > generally are of the opinion that this sort of firmware workaround is ill-advised.
> >> > > > > > We are unaffected by it, so I certainly have no pressure to
> >> > > > > > have something working here. It's my desire not to be
> >> > > > > > user-hostile that motivated this patch.
> >> > > > >
> >> > > > > IIUC you guys and Reneas are the only ones who have hardware
> >> > > > > that might be in a spot where users aren't able to update the
> >> > > > > firmware (ie, it's out in production somewhere).
> >> > > >
> >> > > > I dunno if we can really keep thinking like that though. In
> >> > > > terms of people who have devicetrees in the kernel and stuff
> >> > > > available in western catalog distribution, sure.
> >> > > > I don't think we can assume that that covers all users though,
> >> > > > certainly the syntacore folks pop up every now and then, and I
> >> > > > sure hope that Andes etc have larger customer bases than the
> >> > > > in-kernel users would suggest.
> >> > > >
> >> > > > > So I'm adding Geert, though he probably saw this months ago...
> >> > > >
> >> > > > Prabhakar might be a good call on that front. I'm not sure if
> >> > > > the Renesas stuff works on affected versions of OpenSBI though,
> >> > > > guess it depends on the sequencing of the support for the
> >> > > > non-coherent stuff and when this bug was fixed.
> >> > > >
> >> > > ATM, I dont think there are any users who are using the upstream
> >> > > kernel + OpenSBI (apart from me and Geert!). Currently the
> >> > > customers are using the BSP releases.
> >> >
> >> > That doesn't really answer whether or not you (and your customers)
> >> > are using an affected version of the vendor OpenSBI?
> >> > The affected range for OpenSBI itself is [v0.8 to v1.3).
> >>
> >> Did you perhaps miss this mail Prabhakar?
> >>
> > Oops sorry for that.
> >
> > I can confirm the BSP version used by the customers is v1.0 [0].
> >
> > [0]
> > https://jpn01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith
> > ub.com%2Frenesas-rz%2Frz_opensbi%2Fcommits%2Fwork%2FOpenSBI-PMA%2F&dat
> > a=05%7C02%7Cprabhakar.mahadev-lad.rj%40bp.renesas.com%7C014cf4ddfd1e48
> > 1ff5bc08dc00bd467f%7C53d82571da1947e49cb4625a166a4a2a%7C0%7C0%7C638386
> > 060130410731%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luM
> > zIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=a0tcsXY4EQlODi
> > I34QygXS9QpJnVBqL8bNkxE8N5J2g%3D&reserved=0
> 
> OK, so sounds like would end up with broken systems from this bug, then?
> 
> IIRC we still have the Renesas systems as NONPORTABLE due to that DMA pool Kconfig conflict.  So if
> it's really only these Renesas systems that have the bug, maybe we can still remove hibernation from
> NONPORTABLE and just add in some sort of Kconfig to disable the
> Renesas+hibernation combinations that would break?
> 
Well customers using BSP uses v1.0 for OpenSBI and kernel 5.10-cip, and people wanting to run upstream kernel will have to only use the upstream OpenSBI as the OpenSBI used in BSP is not compatible with upstream kernel(Linux doesn’t bootup).

ATM I can say that its only me and Geert using upstream OpenBSI and upstream kernel.

With that in mind would we still require that change?

Cheers,
Prabhakar