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 038B7CDB479 for ; Wed, 24 Jun 2026 14:53:56 +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=5vQQSRz7zTrSnXaHuai6nRBd9Jqxhl+XBqkIboWniPA=; b=XmTXbTaw90scnS u/FT3D+xVHmwd6MX4ID/U3MZseW1t8Ocix0BYR3KwogfdL4v3Ut9uB9TJ3sOnBVo5Kr8c09zgaXSa 0I8tcq719UsbcLqzyA3CyAtx391GaSpY9stnY2YnJdT2ZUli8rmGREBSJgCnaJVbEvfZ30ZDrL6d9 DyKKSevNOGnulcHInYwqMsz/nmUvOwfO7pUP1ui0O0DCmvCyjVRV+u2M2kSeQ9dn+8sPXdm/+lhVN 1RQH2p5pvCEcX3/vQ7xS8tr+YxDPYTU3zblS0EXanLgR+9zxp8pzs/GoWl0nDXaojTauZpk+wUOMW pKOlXSfpLSkvrCp1acDA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wcOz6-00000007wjR-0DLZ; Wed, 24 Jun 2026 14:53:48 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wcOz3-00000007wit-47cQ for linux-arm-kernel@lists.infradead.org; Wed, 24 Jun 2026 14:53:47 +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 5AD212938; Wed, 24 Jun 2026 07:53:40 -0700 (PDT) Received: from [10.2.213.11] (e137867.arm.com [10.2.213.11]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0F3A23F62B; Wed, 24 Jun 2026 07:53:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1782312824; bh=VKjN0gNxqpZoqnuGUfnm3VobutF020Ybxl/mWwfDqos=; h=Date:Subject:To:References:From:Cc:In-Reply-To:From; b=Znz1thJ9AMZxOoNBNzNYFWGyPt1LN3PHgw4womnrdqXUodZcEjyh/os+kuSLRJ+D/ +i45x5YAytdO/kY1WT5oHWd7F5efPW/mp5DlMajJpA7hnM1NMmcur+mIXfGPG4Arpd SXkMhyVcZBoVKK8aRtuWQywLofMrG1a3qzV0541o= Message-ID: <073a55f2-54ff-4770-8457-bef164261a87@arm.com> Date: Wed, 24 Jun 2026 15:53:39 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v15 08/11] arm64/ptrace: Define and use _TIF_SYSCALL_EXIT_WORK To: Jinjie Ruan References: <20260511092103.1974980-1-ruanjinjie@huawei.com> <20260511092103.1974980-9-ruanjinjie@huawei.com> From: Ada Couprie Diaz Content-Language: en-US, en-GB, fr Organization: Arm Ltd. In-Reply-To: <20260511092103.1974980-9-ruanjinjie@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260624_075346_121847_15FB2F3B X-CRM114-Status: GOOD ( 16.00 ) 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, will@kernel.org, kees@kernel.org, thuth@redhat.com, ryan.roberts@arm.com, anshuman.khandual@arm.com, kevin.brodsky@arm.com, pengcan@kylinos.cn, broonie@kernel.org, luto@kernel.org, linux-arm-kernel@lists.infradead.org, wad@chromium.org, yeoreum.yun@arm.com, oleg@redhat.com, linux-kernel@vger.kernel.org, james.morse@arm.com, tglx@kernel.org, liqiang01@kylinos.cn, linusw@kernel.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 11/05/2026 10:21, Jinjie Ruan wrote: > Introduce _TIF_SYSCALL_EXIT_WORK to filter out entry-only flags > during the syscall exit path. This aligns arm64 with the generic > entry framework's SYSCALL_WORK_EXIT semantics. > > [Rationale] > The current syscall exit path uses _TIF_SYSCALL_WORK to decide whether > to invoke syscall_exit_work(). However, _TIF_SYSCALL_WORK includes > flags that are only relevant during syscall entry: > > 1. _TIF_SECCOMP: Seccomp filtering (__secure_computing) only runs > on entry. There is no seccomp callback for syscall exit. > > 2. _TIF_SYSCALL_EMU: In PTRACE_SYSEMU mode, the syscall is > intercepted and skipped on entry. Since the syscall is never > executed, reporting a syscall exit stop is unnecessary. > > [Changes] > - Define _TIF_SYSCALL_EXIT_WORK: A new mask containing only flags > requiring exit processing: _TIF_SYSCALL_TRACE, _TIF_SYSCALL_AUDIT, > and _TIF_SYSCALL_TRACEPOINT. > > - Update exit path: Use _TIF_SYSCALL_EXIT_WORK in > syscall_exit_to_user_mode_work() to avoid redundant calls to > audit and ptrace reporting when only entry-flags are set. > > - Cleanup: Remove the has_syscall_work() helper as it is no longer > needed. Direct flag comparison is now used to distinguish between > entry and exit work requirements. > > [Impact] > audit_syscall_exit() and report_syscall_exit() will no longer be > triggered for seccomp-only or emu-only syscalls. This matches the > generic entry behavior and improves efficiency by skipping unnecessary > exit processing. > > Cc: Mark Rutland > Cc: Will Deacon > Cc: Catalin Marinas > Reviewed-by: Linus Walleij > Reviewed-by: Yeoreum Yun > Signed-off-by: Jinjie Ruan > --- Reviewed-by: Ada Couprie Diaz Definitely not related to this series, but it feels like this brings us quite close to being able to switch to generic TIF flags as well : only TIF_FOREIGN_PSTATE and TIF_MTE_ASYNC_FAULT would need to be moved to the upper 16 bits, with TIF_RESTORE_SIGMASK and TIF_MEMDIE freeing two slots there. Not sure how important the bit number changes would be and if any of the extra generic bits require any arch support (TIF_POLLING_NRFLAG, TIF_USER_RETURN_NOTIFY, TIF_RSEQ, TIF_HRTIMER_REARM)... But again, just thinking out loud ! Thanks, Ada