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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=en+M8qwLLTVyz4mNnIV9oXGc3BXJGTwM/2EcYJ81ZKQ=; b=asD+yze3qDtzs1DH+qhIbeywKr6wydXJkQfq5G3ITHMmn1g45x6tR3JL5fXgCCbh+T nNmcH1Sk3QSHXSr+UrZPP3BnWF04qnl9i3l5SEn0s56GTA39Ul2L0zBGLXW6L60OidWZ r46/x9yAbWCRJy0e9HXJV68WEof5jM894ks3Yu8m75NETJ1PuLDxDR12BeMkAsOS0leZ 7aIhL00R8lLJycBW3O0m9LFH4rthd9/wmKj2xOj/kGx6lXvgvWPMGdjBwkV6PbqQ2O3e g5q+noN7CFEpl3mx9OAbuVpylhz0LHYT9PTH+vXuu3/Yy8TnjwQTd07mIht4Z8bSpF9w 4RMQ== X-Gm-Message-State: AGRZ1gLjrFZ/NRBbTCzX+phONX1xkCE05TGdz1TI1Xg3pC2+lJXBM5az Q1IGqsSzAlaGMmIH7nekGrgc1V6Y9AY1iH8YcIg= X-Google-Smtp-Source: AJdET5fss32b3UWdqZc+Zgo/XhsB1Hriji1NuUqQF0mXw2ZXg34m3rQ8RDTN1XoJb5e0Tixhq3C70900jVJvJ2wyuc8= X-Received: by 2002:aca:b183:: with SMTP id a125-v6mr9373445oif.44.1542004164743; Sun, 11 Nov 2018 22:29:24 -0800 (PST) MIME-Version: 1.0 References: <7958aa50-8808-e909-753c-e232b3d1f84e@packi.ch> In-Reply-To: From: David Abdurachmanov Date: Mon, 12 Nov 2018 07:29:13 +0100 Message-ID: Subject: Re: [PATCH] riscv: add S and U modes to ISA string To: Palmer Dabbelt X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181111_222939_580360_0C30313A X-CRM114-Status: GOOD ( 17.07 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: me@packi.ch, aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org Message-ID: <20181112062913.ReFy2CG8W60fCUNYtHJKfjMaUuI_jvVfY9Ugxr1Yr3U@z> On Sun, Nov 11, 2018 at 11:14 PM Palmer Dabbelt wrote: > > On Sat, 10 Nov 2018 00:35:15 PST (-0800), me@packi.ch wrote: > > On 10.11.18 07:45, David Abdurachmanov wrote: > >> > >> The patch adds the missing S and U modes. > > > > This is the same patch I submitted earlier (see v2 here [1], based on > > Palmer's feedback). Palmer stated that the "S" extension should not be > > exposed to usermode. > > > > Since two people arrived at the same solution, I wonder if the > > supervisor mode should really be hidden from userspace, as it's about > > the CPU information, not about the environment the calling code is > > running as. > > > > [1] https://lkml.org/lkml/2018/11/10/96 > > I still think S should be hidden from applications. This patch was fairly > mechanical, so it probably just wasn't though about twice -- that's the problem > with user ABI stuff, lots of times the obvious answer isn't the correct one :). > True. It was mechanical based on warnings I noticed while booting Fedora with latest kernel and BBL. Also true, that /proc/cpuinfo doesn't need to reveal all things to user space (especially if you don't want various programs to depend on it as some tend to parse /proc/cpuinfo). Note, that on server systems which probably would implement SMBIOS (based on the current proposal for RISC-V) the administrator could check for S mode. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv