From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS17314 8.43.84.0/22 X-Spam-Status: No, score=-3.2 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,PDS_RDNS_DYNAMIC_FP,RCVD_IN_DNSWL_MED,RDNS_DYNAMIC, SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.6 Received: from sourceware.org (ip-8-43-85-97.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id DD7D01F47C for ; Mon, 23 Jan 2023 13:30:13 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=pass (2048-bit key; unprotected) header.d=sifive.com header.i=@sifive.com header.a=rsa-sha256 header.s=google header.b=IDsxW6ox; dkim-atps=neutral Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 89C993858D32 for ; Mon, 23 Jan 2023 13:30:12 +0000 (GMT) Received: from mail-yb1-xb33.google.com (mail-yb1-xb33.google.com [IPv6:2607:f8b0:4864:20::b33]) by sourceware.org (Postfix) with ESMTPS id 481733858D32 for ; Mon, 23 Jan 2023 13:30:00 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 481733858D32 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=sifive.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=sifive.com Received: by mail-yb1-xb33.google.com with SMTP id 66so14738324yba.4 for ; Mon, 23 Jan 2023 05:30:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=mJYRO6ISS1JoIw+4NoLJhtAN47TpIgRoVsNhuK1TFTQ=; b=IDsxW6oxemUUha/V75Vosm332PzzzREw0bxiFe8xpVDc+BcoK78TYTYhJ+8x7kVJyg 6icG8fdkvIC0fJNSxN9UCYR1HnpJLtDhApszUpFrHUU2yJkBN6z3l1GLjkY7MomJCdU7 hrXoOFt24yZ5YXg2Kxd9DbDdscHpkne8M+kdQ5u3K5J7l2txFP79BeyH8zq3T+KExtXM 85JhXnSfyaoEh2oc8sqUGxBdOAZcSpra88wtNATRoIq3Gue8b5Dze034Ad5/UUvz6ZFg 6liocWgINOKq1A5nWwlRtfvzOi7TkW4RU1nY8130w3BQ1XhGCbArMNi20cpPvHySQGwW eVZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=mJYRO6ISS1JoIw+4NoLJhtAN47TpIgRoVsNhuK1TFTQ=; b=5E2OPINdp3f+hEnpgHS5q34SWQlWjLH4EB99dUcEERd9BkV1WF292xjkrG1tnAbiz0 zoiXQjDXFcfPNRFAnqlByIpsvkOhp7pXXYtTIMwuTDfpx0Y8Qv70cPMK8CpZcBXzWmJj wU5avkHTigdvCZS7tnPN1osUoryvRrVKv1hw+EV+YPD2ugb0lfZlcpNVCp4x36Nnnlpd 4Pf7DORy17OVoKe+/uszahuSLgNVLsgw1fXnxmIcH7NWpMf0z5N1Jx/+o6g8HluxzuB+ bvh/jjFOEKNbBSyBMAJ+7Q/d8jA/WOT0m6/y47V2jrRrdpuq0qqH9lpJoY03OXhBP+v1 lTTQ== X-Gm-Message-State: AFqh2kpAi7Wbh56wITOdw3PLgUOJ0fL1qIS7ywTW6i+3HVJpSIEAO3f7 g40VsT1RywlhqAIwUyBIGRR/wmS4X9Ok2XHP8IcHaw== X-Google-Smtp-Source: AMrXdXvkOvyevRYP9wVIGsDLGwRGBxvRFwas2rVYr1z71qDvnBKuuHs1Kv57S7A2C72yUVvVJAUUbg29Bx0rSeLAKqw= X-Received: by 2002:a25:1082:0:b0:803:b8c9:810a with SMTP id 124-20020a251082000000b00803b8c9810amr1104435ybq.345.1674480599538; Mon, 23 Jan 2023 05:29:59 -0800 (PST) MIME-Version: 1.0 References: <3923eeee-e4dc-0911-40bf-84c34aee962d@linaro.org> <119da65f-e976-f382-3fe1-1585be738352@ventanamicro.com> <8be4d673-f435-429e-9a61-bb49e7820529@linaro.org> <6d13e63f-69b3-6e48-b811-bbfcf3ffb3af@ventanamicro.com> In-Reply-To: From: Andy Chiu Date: Mon, 23 Jan 2023 21:29:46 +0800 Message-ID: Subject: Re: Auto-enabling V unit and/or use of elf attributes (was Re: Adding V-ext regs to signal context w/o expanding kernel struct sigcontext to avoid glibc ABI break) To: Conor Dooley Cc: Jeff Law , Richard Henderson , Vineet Gupta , Kito Cheng , Philipp Tomsich , Vincent Chen , Florian Weimer , Rich Felker , Andrew Waterman , Palmer Dabbelt , =?UTF-8?Q?Christoph_M=C3=BCllner?= , davidlt@rivosinc.com, Arnd Bergmann , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Szabolcs Nagy , Greentime Hu , Aaron Durbin , Andrew de los Reyes , linux-riscv , GNU C Library Content-Type: text/plain; charset="UTF-8" X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces+e=80x24.org@sourceware.org Sender: "Libc-alpha" Hey Conor, On Mon, Jan 23, 2023 at 8:18 PM Conor Dooley wrote: > Meh, all of these discussions seem worthwhile to me! > > Now that things have died down though, I'm curious - what are your > plans? Still going to submit another version of this series? > Yes, we have implemented most of it and are planning to send the series in recent days. Thanks to Vineet, he is helping me to sort out some last bits before the submission. Here are some points related to this thread that will be in v13: 1. allocate V context in the first-use trap 2. drop prctl V-controlling because it conflicts with the idea of the first-use trap. 2. sigframe/ptrace will not have V context if a process's VS is off 3. If the kernel is compiled with CONFIG_RISCV_ISA_V enabled, then the auxv always reports size of the sigframe as if there is a V context. This is because user space may need information from auxv to set up an alternative signal stack, and it may not know if it would use V. ARM64 also reports the size assuming all extensions are used. Thanks, Andy