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bh=EqXvKoYqADEjA6zEZSWiBnqob+NV98aFo9Y3mq5PFt4=; b=sRWAKCymZ83rvJB58riy8B6m+MECl/9WckPjTsJ5afX0hVI58qC0mMjUzEdIJAW4CPpsQe nM4tlaPuU6MbCMUj6oXdFJCJ0gqEyJPfdgI+d8V8X4BWUkAoZPYwfMSbxLfs5JohZnLRS/ 8crj6L0sDIsQ8+pIBkMBTVqKC/V8EOU= Date: Tue, 1 Dec 2020 16:25:52 +0100 From: Borislav Petkov To: Rongwei Wang Subject: Re: [PATCH 0/3] arm64:msr: Add MSR driver Message-ID: <20201201152552.GD22927@zn.tnic> References: <20201130174833.41315-1-rongwei.wang@linux.alibaba.com> <20201130190331.GI6019@zn.tnic> <8724DF91-5BF0-4265-8091-F9E0C7DC2F1A@linux.alibaba.com> <20201201112647.GA22927@zn.tnic> <20201201145415.GC22927@zn.tnic> <8ED75067-DB02-4502-BA03-45B3519E408A@linux.alibaba.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8ED75067-DB02-4502-BA03-45B3519E408A@linux.alibaba.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201201_102559_460579_DFD000CB X-CRM114-Status: GOOD ( 12.25 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: gshan@redhat.com, Anson.Huang@nxp.com, geert+renesas@glider.be, catalin.marinas@arm.com, masahiroy@kernel.org, linux-kernel@vger.kernel.org, michael@walle.cc, krzk@kernel.org, bjorn.andersson@linaro.org, vkoul@kernel.org, olof@lixom.net, shawnguo@kernel.org, vincenzo.frascino@arm.com, Will Deacon , ardb@kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Dec 01, 2020 at 11:17:39PM +0800, Rongwei Wang wrote: > In ARM, the system registers can only be accessed through msr and mrs, > so the problem created by MSR driver (depend on rdmsr and wrmsr) in > x86 is not necessarily present in ARM, which is very different from > x86. No, the point I'm making is that it doesn't matter what the architecture does or does not, register *writes* from userspace are a bad bad idea for the reasons I described. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel