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[174.21.149.226]) by smtp.gmail.com with ESMTPSA id y30sm15323488pff.67.2020.04.07.20.44.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 07 Apr 2020 20:44:49 -0700 (PDT) Subject: Re: [PATCH for-5.0?] linux-user/ppc: Fix padding in mcontext_t for ppc64 To: David Gibson References: <20200407032105.26711-1-richard.henderson@linaro.org> <20200408021006.GB44664@umbus.fritz.box> From: Richard Henderson Message-ID: Date: Tue, 7 Apr 2020 20:44:47 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200408021006.GB44664@umbus.fritz.box> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::544 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alex.bennee@linaro.org, qemu-ppc@nongnu.org, qemu-devel@nongnu.org, laurent@vivier.eu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 4/7/20 7:10 PM, David Gibson wrote: >> Should we in fact disable ppc64abi32? >> I can't see how it could work enough to be useful as-is. > > Yeah, I think so. Last time we had a problem in this area, I couldn't > even figure out what ppc64abi32 was supposed to *be*, let alone what > the use case for it is. Given that, it's hard to imagine it's been > working (whatever that means) any time recently. What it's *supposed* to be is a ppc32 binary running on a 64-bit cpu, e.g. a 32-bit binary on power7 with the kernel's compat syscalls. You get to do native 64-bit arithmetic and have 32-bit pointers. I guess there's a kind of a use case there somewhere, but it's rather niche, and someone has to care more than they have until now. r~