From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1B4DC43461 for ; Tue, 18 May 2021 06:44:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 95CB3611BD for ; Tue, 18 May 2021 06:44:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346829AbhERGpi (ORCPT ); Tue, 18 May 2021 02:45:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346788AbhERGpg (ORCPT ); Tue, 18 May 2021 02:45:36 -0400 Received: from mail-oi1-x22d.google.com (mail-oi1-x22d.google.com [IPv6:2607:f8b0:4864:20::22d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6654EC06138A for ; Mon, 17 May 2021 23:44:15 -0700 (PDT) Received: by mail-oi1-x22d.google.com with SMTP id c3so8811200oic.8 for ; Mon, 17 May 2021 23:44:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Bcn5fb5DZjb4YtyFgvoiwHqnuY6hbdNmIIbEt5dAaVo=; b=XDBwjWcK7W4iYUwj/u/gw3oqWIeA5hEElNrFlEm/M/WFUJONMDfGqLm0lYCC+OjVVz mBgaZXFe6JWlW8DEdYhnwpSSaIRw0JBMAxOW0eBVYiQFPbdWqcu54BOcbIVGfHSisc53 0eyg+JwZ9Zva8VFoFU411tL9M2+QC38Hjni0baTANedHQf4FpzkVI0oa6ycvizeUlS3n 5kPELVbFvsBKGkfPkPB8Sc/9Eg/h0xc520RY7bKeRNVQmlg8SXch0vnHz/n109DuhTYB 8K9AfhJC/iujNgus17kDXKo/Uh34SKdrvrUQDCjtSEc9j/VfiBuN4vjJ0FXUFAU/LtOV +NUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Bcn5fb5DZjb4YtyFgvoiwHqnuY6hbdNmIIbEt5dAaVo=; b=BTHt5rAHOxA73Z8ARIchbXnOpOGhMOKtkdeDawrc2NbO1YZWkR47rckU/Jc3YiWKDr Hy0HCK7r1dRqsN4E3i2Uvs+cVJVQovZhbOnBztfu1otBz9Z+TC/Fae8obmXLhfIe45hb sFjhDWxOpZXopuznLyytv5wT7RT8BsIjz1vcGCI7QDd61c9mgX07541yjNW/r/3+L5l/ geOYtL0i7OnwY/c/LohxI/50I9Tby3RySpXTibuU+4qOldV9bfsWUYj03xeegNdfirB6 +ArjT53saoKRi70SCWfpZIO4sy6ioZC7CaQIbCrbwiSQtlsK3TPwO+VRDbEmaXLngIiS u1Dg== X-Gm-Message-State: AOAM531crFyVOdQTKktTo30D4fyIdkAnbsvpzv5jfh79GIZAsBYpRv9g az10hE4o3wWlHyF3QDZ9jv5wgAGzABlQMUMjKRcNkA== X-Google-Smtp-Source: ABdhPJyZJEKSXeod3K8VlVQioQOKfP1BRvVdjkXF95l+TeGhJwUZcia8n6Cqhfj41s9XfUXYiQJrlqfEJySBhCKYcEE= X-Received: by 2002:a05:6808:144f:: with SMTP id x15mr2779174oiv.172.1621320254598; Mon, 17 May 2021 23:44:14 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Marco Elver Date: Tue, 18 May 2021 08:44:03 +0200 Message-ID: Subject: Re: [PATCH v4 0/5] siginfo: ABI fixes for TRAP_PERF To: "Eric W. Biederman" Cc: Arnd Bergmann , Florian Weimer , "David S. Miller" , Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Peter Collingbourne , Dmitry Vyukov , Alexander Potapenko , sparclinux , linux-arch , Linux Kernel Mailing List , Linux API , kasan-dev Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Tue, 18 May 2021 at 05:47, Eric W. Biederman wrote: > > Marco Elver writes: > > > On Mon, 17 May 2021 at 21:58, Eric W. Biederman wrote: > >> > >> During the merge window an issue with si_perf and the siginfo ABI came > >> up. The alpha and sparc siginfo structure layout had changed with the > >> addition of SIGTRAP TRAP_PERF and the new field si_perf. > >> > >> The reason only alpha and sparc were affected is that they are the > >> only architectures that use si_trapno. > >> > >> Looking deeper it was discovered that si_trapno is used for only > >> a few select signals on alpha and sparc, and that none of the > >> other _sigfault fields past si_addr are used at all. Which means > >> technically no regression on alpha and sparc. > >> > >> While the alignment concerns might be dismissed the abuse of > >> si_errno by SIGTRAP TRAP_PERF does have the potential to cause > >> regressions in existing userspace. > >> > >> While we still have time before userspace starts using and depending on > >> the new definition siginfo for SIGTRAP TRAP_PERF this set of changes > >> cleans up siginfo_t. > >> > >> - The si_trapno field is demoted from magic alpha and sparc status and > >> made an ordinary union member of the _sigfault member of siginfo_t. > >> Without moving it of course. > >> > >> - si_perf is replaced with si_perf_data and si_perf_type ending the > >> abuse of si_errno. > >> > >> - Unnecessary additions to signalfd_siginfo are removed. > >> > >> v3: https://lkml.kernel.org/r/m1tuni8ano.fsf_-_@fess.ebiederm.org > >> v2: https://lkml.kernel.org/r/m14kfjh8et.fsf_-_@fess.ebiederm.org > >> v1: https://lkml.kernel.org/r/m1zgxfs7zq.fsf_-_@fess.ebiederm.org > >> > >> This version drops the tests and fine grained handling of si_trapno > >> on alpha and sparc (replaced assuming si_trapno is valid for > >> all but the faults that defined different data). > > > > And just to clarify, the rest of the series (including static-asserts) > > for the next merge-window will be sent once this series is all sorted, > > correct? > > That is the plan. > > I really wonder about alphas use of si_trapno, and alphas use send_sig > instead of force_sig. It could be worth looking into those as it > has the potential to simplify the code. > > >> Eric W. Biederman (5): > >> siginfo: Move si_trapno inside the union inside _si_fault > >> signal: Implement SIL_FAULT_TRAPNO > >> signal: Factor force_sig_perf out of perf_sigtrap > >> signal: Deliver all of the siginfo perf data in _perf > >> signalfd: Remove SIL_PERF_EVENT fields from signalfd_siginfo > > > > Looks good, thank you! I build-tested (defconfig -- x86_64, i386, arm, > > arm64, m68k, sparc, alpha) this series together with a local patch to > > pull in the static asserts from v3. Also re-ran perf_events kselftests > > on x86_64 (native and 32bit compat). > > Thanks, > > Can I have your Tested-by? Of course, Tested-by: Marco Elver Thanks, -- Marco