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See http://www.infradead.org/rpr.html X-Stat-Signature: u1b1sxbk4gqw57dhgkgaciatknrhmpeg X-Rspam-User: X-Rspamd-Queue-Id: EC5CE140005 X-Rspamd-Server: rspam06 X-HE-Tag: 1675233109-635151 X-HE-Meta: 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 Ykufe3yi t4U7Itr+koyfbraJYwNReqGMQHBkPItJ3s5Qa1FTlHSNBa64dcycRXHg72TY+6WyZJdFC5QnQLOMyJ7fGQpms4u4fudctGKZSNl/JMuFywL9JQDTiLdWrrSTsefvFhZKEVAz9ct/XRRqpcu4CmO81AO2Fvf1NIGft48frsPoUeC2v6wKAhV1H8da+cjVMYnIjDGaITTbwtWohW/7xRfEEpaV4VyOEd28jU6Wr7hOQ4Zmubj5F3/hgd15TeyA5uV8v4sI76ojJnkZhUXp4DmtkwTKtRvkGFtw2VeB5KR76siSHEqAYzAuHVxBlhh3RL2Ck7kLl2Toa57OgqnkM0T+Kx1pW9SfjFykfN+NGogyTIMbEvs9bWtnMlqldjmquNEDwP4X6hEt4MYp7JDHIcEPFlg9Ysjx2gJvjeZVsYppK8w/OS+Lq9FxCHP/eydy07BtxDHvEXJMnQkFSRYcrqTR+Ldx/peR9cQAbTayb X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jan 30, 2023 at 03:24:40PM +0000, Matthew Wilcox wrote: > > Basically we are making use of the memory protection unit (MPU) so > > that only M-mode is allowed to access this region and S/U modes are > > blocked. > > This sounds like RISC-V terminology. I have no idea what M, S or U > modes are (Supervisor and User, I'd guess for the last two?) Yes, M = Machine, S = Supervisor, and U = User. M omde is the absolutele worst idea of RISC-V and basically a mix of microcode and super-SMM mode. > Before we go too deeply into it, how much would it cost to buy all of > these parts and feed them into a shredder? I'm not entirely joking; > if it's less than the software engineering time it'd take to develop > and support this feature, we should do it. The above suggests this is in no way an actual hardware problem, but the stupid decision is done in the M-Mode firmware. I think it is very reasonable to simply not support the devices in Linux until the firmware is fixed.