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[173.198.77.218]) by smtp.gmail.com with ESMTPSA id u1-20020a17090ae00100b00227223c58ecsm6704110pjy.42.2023.02.23.07.36.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Feb 2023 07:36:47 -0800 (PST) Message-ID: <73714633-3e5d-80ba-4882-1457f417e443@linaro.org> Date: Thu, 23 Feb 2023 05:36:44 -1000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: Feature request for enabling SCTLR_ELx.nAA Content-Language: en-US To: Catalin Marinas Cc: linux-arm-kernel@lists.infradead.org, =?UTF-8?Q?Alex_Benn=c3=a9e?= , Will Deacon , Mark Rutland References: From: Richard Henderson In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230223_073650_913600_AECE2ADF X-CRM114-Status: GOOD ( 11.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2/23/23 02:15, Catalin Marinas wrote: > Given that allowing unaligned accesses could break atomicity, I wouldn't > set this bit to 1 permanently, it helps catching tricky software bugs. > So a prctl() makes more sense. If your intended use is just preserving > the acquire/release semantics, I don't think these are affected by the > atomicity rules even if they go across a 16-byte boundary. Yes, my intended use is just the acquire/release. As I read the Arm ARM pseudo-code for aarch64/functions/memory/Mem, the !aligned case devolves to a series of bytes, but with the same acctype, so each byte is AccType_ORDERED. Which is just fine for my use case. r~ _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel