Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230525-postnasal-monopoly-98adb96ffaa1@wendy>
 <CAAhSdy06nQh4H1FP_K_-VF462mhj+F2M=4AV4QSCUGe5XVqX0g@mail.gmail.com>
 <20230525-shrapnel-precut-26500fca4a48@wendy> <CAAhSdy3SqeLdAfaojUki=ht21nr4ZUPMkW_t9M6ntQCt6Ds4Nw@mail.gmail.com>
 <20230525-citric-waged-a2f78d27eb0c@wendy> <CAOnJCULfC0jmiucLNMeJZwJf4QbGAN6r4B-ubUbP16KVpxrCfA@mail.gmail.com>
 <20230525-flaring-trading-f2bf0713ae26@spud> <CAOnJCUK_EgX-En1QNS8yX1WA1nj8w2kpvXMQcvgWuR3dvzEQYw@mail.gmail.com>
 <20230525-desecrate-imposing-d97ab34e06ad@spud> <CAOnJCUKfRv68Bh8ue=ZhMGxai9_UEHLpm3553g2c2NXh-RP-TQ@mail.gmail.com>
 <20230525-batting-botch-7e03393a2d97@spud>
In-Reply-To: <20230525-batting-botch-7e03393a2d97@spud>
From:   Alexandre Ghiti <alexghiti@rivosinc.com>
Date:   Fri, 26 May 2023 15:14:33 +0200
Message-ID: <CAHVXubiDezbwZO6X2btvgpq-XqHnxZjXzaMnSK2YrHc_ioLx8Q@mail.gmail.com>
Subject: Re: Bug report: kernel paniced when system hibernates
To:     Conor Dooley <conor@kernel.org>,
        =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@rivosinc.com>
Cc:     Atish Patra <atishp@atishpatra.org>,
        Conor Dooley <conor.dooley@microchip.com>,
        Anup Patel <anup@brainfault.org>,
        Anup Patel <apatel@ventanamicro.com>,
        Alexandre Ghiti <alex@ghiti.fr>, robh@kernel.org,
        jeeheng.sia@starfivetech.com, linux-kernel@vger.kernel.org,
        palmer@rivosinc.com, leyfoon.tan@starfivetech.com,
        mason.huo@starfivetech.com, Guo Ren <guoren@kernel.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Song Shuai <suagrfillet@gmail.com>,
        linux-riscv@lists.infradead.org,
        Andrew Jones <ajones@ventanamicro.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Hi everyone,

On Thu, May 25, 2023 at 11:24=E2=80=AFPM Conor Dooley <conor@kernel.org> wr=
ote:
>
> On Thu, May 25, 2023 at 01:06:04PM -0700, Atish Patra wrote:
> > On Thu, May 25, 2023 at 11:39=E2=80=AFAM Conor Dooley <conor@kernel.org=
> wrote:
> > >
> > > On Thu, May 25, 2023 at 11:37:40AM -0700, Atish Patra wrote:
> > >
> > > > Any testing of hibernation still needs to revert the patch until we
> > > > have the proper fix.
> > >
> > > "the patch" is what exactly? I assume you don't mean depending on
> > > NONPORTABLE, since that is a Kconfig option.
> >
> > Nope. Sorry I meant the commit
> >
> > 3335068 ("riscv: Use PUD/P4D/PGD pages for the linear mapping")
>
> Ah, if your SBI implementation is one of the affected ones, yeah.
> If not, you can just set NONPORTABLE :)

@Bj=C3=B6rn T=C3=B6pel emitted the idea of excluding from the hibernation a=
ll
the memory nodes in the "/reserved-memory" node
(https://elixir.bootlin.com/linux/v6.4-rc1/source/Documentation/devicetree/=
bindings/reserved-memory/reserved-memory.yaml):
I have to admit that I don't see why it is not done by default by the
kernel.

Unless there is stuff in this node that needs to be "hibernated", I
think that would be a very good solution since we would not rely on
the name of the "internal" nodes of "/reserved-memory" (i.e.
"mmode_resv").

I'm digging into why it is not done by default, just wanted to have
your feedback before the week-end :)