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[99.152.116.91]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-219dc962d53sm32904585ad.33.2024.12.20.11.54.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Dec 2024 11:54:37 -0800 (PST) Date: Fri, 20 Dec 2024 11:53:47 -0800 From: Olof Johansson To: Ben Dooks Cc: felix.chong@codethink.co.uk, lawrence.hunter@codethink.co.uk, roan.richmond@codethink.co.uk, linux-riscv@lists.infradead.org Subject: Re: RFC: riscv64 big endian system attempt Message-ID: References: <20241220155801.1988785-1-ben.dooks@codethink.co.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20241220155801.1988785-1-ben.dooks@codethink.co.uk> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241220_115439_004284_04C9FFA9 X-CRM114-Status: GOOD ( 14.75 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Fri, Dec 20, 2024 at 03:57:46PM +0000, Ben Dooks wrote: > With the latest spec adding configurable endianness, we thought we > should try putting together a proof of concept riscv64 big endian. > > The full information is documented on our gitlab[1] which includes > source repositories, build information and project documentation. > > We have a minimal buildroot, qemu and kernel working on QEMU. > > As this is a work in progress any review or help is appreciated. While this is neat, I wonder if there's any real point in picking this up broadly and enabling it, with the associated overhead to keep it maintained? While big endian ppc64 will always be close to my heart, little endian really has taken over the world by now, even on ppc64. It used to be that networking was the area that BE was a (soft) requirement, but with modern CPUs having advanced faster than memory latencies and speed, doing endian conversion in software doesn't seem to be a big deal any more. As far as I know, ARM platforms are in the same boat -- they did some early enablement, driven by a couple of specific use cases that didn't significantly grow and are used in very narrow environment and with very limited userspace. Is this a parallel situation to that, or are there reasons to support BE more broadly? It seems like it'd mostly split efforts and add overhead to make sure it's still supported, even if it's a fun project to prove that it works. -Olof _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv