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Sun, 20 Sep 2026 05:32:21 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ThreadId: AzgOxjlYMeWB Date: Sun, 20 Sep 2026 11:30:34 +0200 From: "Arnd Bergmann" To: "Qingfang Deng" Cc: Linux-Arch , "Catalin Marinas" , "Will Deacon" , "Mark Rutland" , "Anshuman Khandual" , "Vikram Sethi" , "Mike Rapoport" , "Shanker Donthineni" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Message-Id: <3250a625-7900-40a9-8f3c-612d333122dc@app.fastmail.com> In-Reply-To: <9895e60c-6a3c-40c8-b188-51891ee6b216@linux.dev> References: <20260920014357.7069-1-qingfang.deng@linux.dev> <20260920014357.7069-3-qingfang.deng@linux.dev> <5847c824-8d69-4d02-af2f-896bf47f0732@app.fastmail.com> <9895e60c-6a3c-40c8-b188-51891ee6b216@linux.dev> Subject: Re: [PATCH v2 3/3] arm64: use generic MMIO accessors Content-Type: text/plain Content-Transfer-Encoding: 7bit On Sun, Sep 20, 2026, at 11:24, Qingfang Deng wrote: > > Regarding unaligned accesses, the splitting can only happen when the > address is known to be unaligned at compile-time. Do these accessors > need to support unaligned MMIO? If so, I could add > OPTIMIZER_HIDE_VAR(addr) to the generic accessors. I think all architectures that have had this problem just started using the inline asm variant, and I'd probably try to encourage that more. What might be helpful here would be to split out the __raw_* helpers into a separate header that is explicitly included on architectures without their own definitions, and an updated comment that explains that architectures are encouraged to implement these as inline asm instead of using the volatile load/store. Arnd