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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 18945C433E6 for ; Fri, 26 Feb 2021 15:33:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CFDE564EED for ; Fri, 26 Feb 2021 15:33:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230049AbhBZPdY (ORCPT ); Fri, 26 Feb 2021 10:33:24 -0500 Received: from mail.efficios.com ([167.114.26.124]:57494 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229545AbhBZPdU (ORCPT ); Fri, 26 Feb 2021 10:33:20 -0500 Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 6D5E830F9D0; Fri, 26 Feb 2021 10:32:36 -0500 (EST) Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id 1wx23JkX2j13; Fri, 26 Feb 2021 10:32:36 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id E7E1A30F9CF; Fri, 26 Feb 2021 10:32:35 -0500 (EST) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com E7E1A30F9CF DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1614353556; bh=lIk0nJ/zoaoI4S6yz+QKK2lq/rImbycdfBHkfxXXItg=; h=Date:From:To:Message-ID:MIME-Version; b=b/t4RyJaCI9evNkbJeINEt0bSsVocZtyHQIvdGzgoGqVZ7mimfuomwXIX3wMj3yTP R1FszRRf2HOPLXyFLuAu+XeUAPa1DFVwh4DTLZragq7YI58oXxK2XaDCb71RFdR93S uMtdalk1ZnfSieo2pa4bTjeqTveMn8GNMMEZWq+8Oqlq6BZ0Kyt9VAk4BmReYTFT3w Ma8oFLbAiOcm4EDUhlitHn1n9b6GbHcpxvJOuSaNjFw/TWeLhDQYIIMrceeDl37yP4 KVbh0Wu1CZW3JBtuJV7kqgulO3QuM2bchgjdceFsa75T0vDch/xM5c0hKSufey1L10 JlHdgrGAHhk5Q== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id nI_BGAxrNA_7; Fri, 26 Feb 2021 10:32:35 -0500 (EST) Received: from mail03.efficios.com (mail03.efficios.com [167.114.26.124]) by mail.efficios.com (Postfix) with ESMTP id D4EED30F9CE; Fri, 26 Feb 2021 10:32:35 -0500 (EST) Date: Fri, 26 Feb 2021 10:32:35 -0500 (EST) From: Mathieu Desnoyers To: Piotr Figiel Cc: Andrew Morton , Peter Zijlstra , paulmck , Boqun Feng , Oleg Nesterov , "Dmitry V. Levin" , Florian Weimer , Alexey Dobriyan , Andrei Vagin , linux-kernel , Peter Oskolkov , Kamil Yurtsever , Chris Kennelly , Paul Turner , emmir , linux-man , linux-api Message-ID: <192824546.8190.1614353555831.JavaMail.zimbra@efficios.com> In-Reply-To: <20210226135156.1081606-1-figiel@google.com> References: <20210226135156.1081606-1-figiel@google.com> Subject: Re: [PATCH v2] ptrace: add PTRACE_GET_RSEQ_CONFIGURATION request MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.26.124] X-Mailer: Zimbra 8.8.15_GA_3996 (ZimbraWebClient - FF86 (Linux)/8.8.15_GA_4007) Thread-Topic: ptrace: add PTRACE_GET_RSEQ_CONFIGURATION request Thread-Index: 8ww6gQARVjS9yplUpDDdbZG1dtieAw== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- On Feb 26, 2021, at 8:51 AM, Piotr Figiel figiel@google.com wrote: [...] > --- > v2: > Applied review comments: > - changed return value from the ptrace request to the size of the > configuration structure > - expanded configuration structure with the flags field and > the rseq abi structure size > [...] > +#define PTRACE_GET_RSEQ_CONFIGURATION 0x420f > + > +struct ptrace_rseq_configuration { > + __u64 rseq_abi_pointer; > + __u32 rseq_abi_size; > + __u32 signature; > + __u32 flags; > + __u32 pad; > +}; > + [...] > +#ifdef CONFIG_RSEQ > +static long ptrace_get_rseq_configuration(struct task_struct *task, > + unsigned long size, void __user *data) > +{ > + struct ptrace_rseq_configuration conf = { > + .rseq_abi_pointer = (u64)(uintptr_t)task->rseq, > + .rseq_abi_size = sizeof(*task->rseq), > + .signature = task->rseq_sig, > + .flags = 0, > + }; > + > + size = min_t(unsigned long, size, sizeof(conf)); > + if (copy_to_user(data, &conf, size)) > + return -EFAULT; > + return sizeof(conf); > +} I think what Florian was after would be: struct ptrace_rseq_configuration { __u32 size; /* size of struct ptrace_rseq_configuration */ __u32 flags; __u64 rseq_abi_pointer; __u32 signature; __u32 pad; }; where: .size = sizeof(struct ptrace_rseq_configuration), This way, the configuration structure can be expanded in the future. The rseq ABI structure is by definition fixed-size, so there is no point in having its size here. Florian, did I understand your request correctly, or am I missing your point ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com