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;
In-Reply-To: <20230526-astride-detonator-9ae120051159@wendy>
References: <20230526-astride-detonator-9ae120051159@wendy>
Subject: Re: [PATCH v1] RISC-V: mark hibernation as nonportable
Message-Id: <168554541142.21606.8005252517231405209.b4-ty@rivosinc.com>
Date:   Wed, 31 May 2023 08:03:31 -0700
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Cc:     Conor Dooley <conor@kernel.org>, atishp@atishpatra.org,
        anup@brainfault.org, alex@ghiti.fr, linux-kernel@vger.kernel.org,
        linux-riscv@lists.infradead.org,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Song Shuai <suagrfillet@gmail.com>,
        JeeHeng Sia <jeeheng.sia@starfivetech.com>
From:   Palmer Dabbelt <palmer@rivosinc.com>
To:     Palmer Dabbelt <palmer@dabbelt.com>,
        Conor Dooley <conor.dooley@microchip.com>
Precedence: bulk


On Fri, 26 May 2023 11:59:08 +0100, Conor Dooley wrote:
> Hibernation support depends on firmware marking its reserved/PMP
> protected regions as not accessible from Linux.
> The latest versions of the de-facto SBI implementation (OpenSBI) do
> not do this, having dropped the no-map property to enable 1 GiB huge
> page mappings by the kernel.
> This was exposed by commit 3335068f8721 ("riscv: Use PUD/P4D/PGD pages
> for the linear mapping"), which made the first 2 MiB of DRAM (where SBI
> typically resides) accessible by the kernel.
> Attempting to hibernate with either OpenSBI, or other implementations
> following its lead, will lead to a kernel panic ([1], [2]) as the
> hibernation process will attempt to save/restore any mapped regions,
> including the PMP protected regions in use by the SBI implementation.
> 
> [...]

Applied, thanks!

[1/1] RISC-V: mark hibernation as nonportable
      https://git.kernel.org/palmer/c/ed309ce52218

Best regards,
-- 
Palmer Dabbelt <palmer@rivosinc.com>