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([2a01:e0a:e17:9700:16d2:7456:6634:9626]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a4efe74111sm17733484f8f.56.2025.06.03.00.32.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Jun 2025 00:32:16 -0700 (PDT) Message-ID: <352704e1-2ef7-4141-a6a9-896981d8afa1@rivosinc.com> Date: Tue, 3 Jun 2025 09:32:15 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/3] riscv: misaligned: fix misaligned accesses handling in put/get_user() To: David Laight Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , "Maciej W . Rozycki" References: <20250602193918.868962-1-cleger@rivosinc.com> <20250602220855.519e23e5@pumpkin> Content-Language: en-US From: =?UTF-8?B?Q2zDqW1lbnQgTMOpZ2Vy?= In-Reply-To: <20250602220855.519e23e5@pumpkin> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 02/06/2025 23:08, David Laight wrote: > On Mon, 2 Jun 2025 21:39:13 +0200 > Clément Léger wrote: > > ... >> The second solution was the one chosen as there are too many callsites to >> put/get_user() that could potentially do misaligned accesses. We tried >> two approaches for that, either split access in two aligned accesses >> (and do RMW for put_user()) > > You can't do RMW because it is visible to other threads. Ahem yeah indeed, so the only way was to do individual lb at least up to some alignment. Thanks, Clément > > David