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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7139BD2D8F9 for ; Tue, 27 Jan 2026 11:03:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:Content-Type:In-Reply-To:From:References:To:Subject :MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=N1lvjaqhQkj8mEhgS24AJuAb84AsUGZxYBbZPk8F7T0=; b=uAS1QxS5WZ37tq JZkzuQCHED61RY9LdGCSc9nkul44pVQpDvrcDw8byBQEnsdELMOxvc4HEShHHfvDNE77X65xCUZ6u 6ZoqPIAFDWWyAvwdNqEvw/wdpftPsodoZuZeYsTsKozS7hysRVURVwFL8wxLwMbEQCDLz1ZfrlVD1 /wZob8HxpyLyLd1asK+c8tNXwu0DcghcqSKJgCno2EFJlcG/9rVX5FxBNTpbjSw+7SaX2Q+4h0jwl yVdiwHspzNLWWCXZCCNa3apC1Sg6AWf68a2owYkOK8mJ70gSWQ9G9s07hUZY0UBrzhDV2pU/2I3Cc ubKOg/o/+YB5JZN89DnA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkgqe-0000000E7GG-3Mee; Tue, 27 Jan 2026 11:03:04 +0000 Received: from canpmsgout05.his.huawei.com ([113.46.200.220]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkgqX-0000000E7BZ-1RK8 for linux-arm-kernel@lists.infradead.org; Tue, 27 Jan 2026 11:02:59 +0000 dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=N1lvjaqhQkj8mEhgS24AJuAb84AsUGZxYBbZPk8F7T0=; b=QwPX77kTAsPwEGUrVO4XKyg2YdoWDEWGAFhgbz7Ies+eHt/UsfIeyjihwTY4t4E0HZjIXkQ/a spYLNzK4fiuuiJACK7ymK7g6u2GjAMSV5316vf9LN8VKUFu2VSitTuDGq5ZCkBKGM1EZIqDAc4+ KczS/IDtVMrt0z5qDVCO/w0= Received: from mail.maildlp.com (unknown [172.19.162.144]) by canpmsgout05.his.huawei.com (SkyGuard) with ESMTPS id 4f0j7t5Z0Zz12LD7; Tue, 27 Jan 2026 18:58:50 +0800 (CST) Received: from dggpemf500011.china.huawei.com (unknown [7.185.36.131]) by mail.maildlp.com (Postfix) with ESMTPS id 92A6D40567; Tue, 27 Jan 2026 19:02:45 +0800 (CST) Received: from [10.67.109.254] (10.67.109.254) by dggpemf500011.china.huawei.com (7.185.36.131) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Tue, 27 Jan 2026 19:02:41 +0800 Message-ID: Date: Tue, 27 Jan 2026 19:02:39 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.0 Subject: Re: [PATCH v10 04/16] arm64/ptrace: Refactor syscall_trace_enter/exit() Content-Language: en-US To: Kevin Brodsky , Will Deacon References: <20251222114737.1334364-1-ruanjinjie@huawei.com> <20251222114737.1334364-5-ruanjinjie@huawei.com> <4f07254d-b158-a1ce-69a7-4fa4b0f339c1@huawei.com> <532b42e2-3417-4e0f-af59-8c79521c34a3@arm.com> From: Jinjie Ruan In-Reply-To: <532b42e2-3417-4e0f-af59-8c79521c34a3@arm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.109.254] X-ClientProxiedBy: kwepems200002.china.huawei.com (7.221.188.68) To dggpemf500011.china.huawei.com (7.185.36.131) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260127_030257_822540_D37B8B58 X-CRM114-Status: UNSURE ( 9.81 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, peterz@infradead.org, catalin.marinas@arm.com, ldv@strace.io, song@kernel.org, linux-kselftest@vger.kernel.org, shuah@kernel.org, kees@kernel.org, linux-arm-kernel@lists.infradead.org, kmal@cock.li, thuth@redhat.com, ryan.roberts@arm.com, anshuman.khandual@arm.com, charlie@rivosinc.com, pengcan@kylinos.cn, broonie@kernel.org, luto@kernel.org, tglx@linutronix.de, richard.weiyang@gmail.com, dvyukov@google.com, wad@chromium.org, oleg@redhat.com, linux-kernel@vger.kernel.org, liqiang01@kylinos.cn, akpm@linux-foundation.org, reddybalavignesh9979@gmail.com, macro@orcam.me.uk Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2026/1/27 17:43, Kevin Brodsky wrote: > On 27/01/2026 04:01, Jinjie Ruan wrote: >>> I understand that you're gradually making the arch code more similar to >>> the core code so that we can switch over to it, but I'm struggling to >>> understand why syscall_trace_enter() takes the 'syscall' argument. >>> >>> Even the core code just seems to use it as a local variable, which it >>> overrides before it ever uses it. What am I missing? >> Hi, >> >> You're absolutely right. The 'syscall' parameter is indeed treated as a >> local variable and gets overridden before any real use. Should we >> refactor to remove the parameter entirely in generic entry? > > I noticed this as well, removing it from the generic function would make > sense. AFAICT that removal could be propagated quite far in fact: > syscall_enter_from_user_mode_work(), syscall_enter_from_user_mode(), > even arch implementation (do_syscall_64() on x86). Not really, it is the default return value of syscall_enter_from_user_mode_work() as below, so we only need to remove the parameter in syscall_trace_enter(). static __always_inline long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall) { unsigned long work = READ_ONCE(current_thread_info()->syscall_work); if (work & SYSCALL_WORK_ENTER) syscall = syscall_trace_enter(regs, work); return syscall; } > > - Kevin >