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 D46E0C88E41 for ; Tue, 27 Jan 2026 14:54:53 +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=qlkozp+bRjeQMwIC+OSYzGwx9bLAelORoAYDdM8sGNQ=; b=siEd+C5RXXBLhN TNiSZeEbDJbt8ww7XI6zRctCHe/rQZ/0uY5OduL95MtboPVZJa2eJksibitTQVobFSiYDD9LVbBN6 bCCfSq1TSvihPcy+mp6Da/5gd/cIT+vzK1h0kfAw0xV7vbVqfugXdpjeBTUw4/uVXZOJoQh+FZdFw hEwSSmAR2lXmd/TMAoQnJ1gO3u/KxH/6TY+mHCKaYv9ia6IRkS+uv2T5IcHOvtxBzhaqCAbwiaU+d V6tZDxZgMMFASpFBQjQIrjXqP+3w1gZ1xvhRxCQlAe01PS8/6zCFxZWDEHeBUOoRVcYrbqplqY8pQ wGcHWFMRywG/CQlV3sLw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkkSu-0000000ETuQ-3p6x; Tue, 27 Jan 2026 14:54:48 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkkSs-0000000ETu1-1KNM for linux-arm-kernel@lists.infradead.org; Tue, 27 Jan 2026 14:54:47 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D7E6F1595; Tue, 27 Jan 2026 06:54:37 -0800 (PST) Received: from [10.57.52.3] (unknown [10.57.52.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3A14F3F632; Tue, 27 Jan 2026 06:54:38 -0800 (PST) Message-ID: <666db2a4-6015-46ac-8eba-565beff8b0c1@arm.com> Date: Tue, 27 Jan 2026 15:54:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 04/16] arm64/ptrace: Refactor syscall_trace_enter/exit() To: Jinjie Ruan , 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: Kevin Brodsky Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260127_065446_400956_0E307ED0 X-CRM114-Status: GOOD ( 12.75 ) 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, richard.weiyang@gmail.com, 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, 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 27/01/2026 12:02, Jinjie Ruan wrote: > > 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; > } You're right, hadn't realised the call to syscall_trace_enter() was conditional. - Kevin