From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AE2593002D0; Mon, 1 Dec 2025 10:18:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764584283; cv=none; b=BXXuJwsTYZ9Cl3/stNmyTOQws4txSMh1/rRdnSAQ0kTdzILGtFbD8Lakp8LhhLkkZNa+ExcdEX2o/4RGk2m83ryZFV2QcOFhu/tTRRpSgsfsLQjp2Gg7GGf28HOGw9CuPcOeLYOfSthuL9PJ3ZSFq86fuGvKIB4JjQl8Zg1cXZo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764584283; c=relaxed/simple; bh=0ohCcHE9Ps+Wxv0p+B+GebAPjC2U8EY2WYXm4N9ptDA=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=R/+0TooA+UwfUP/a4XpfhP9/yD/wGgl/NAvwTAYQX9+JTmXmTW6kSoX5Ui0aWDPszqC0znwrermQl7wVl27QdQLN+VXhD2tZjRNvVotee4/CKfTgHtuhtdq6118vLD/8m4xkIncN85egNQ6VStIRSZa7QCyT1lP3wGQ+9gzVSJY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 49C01FEC; Mon, 1 Dec 2025 02:17:52 -0800 (PST) Received: from [10.57.43.170] (unknown [10.57.43.170]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D606E3F73B; Mon, 1 Dec 2025 02:17:54 -0800 (PST) Message-ID: <65c7307b-1f4e-4ae7-8bcf-8bfd9a9186fb@arm.com> Date: Mon, 1 Dec 2025 11:17:52 +0100 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 11/12] arm64: entry: Convert to generic entry To: Jinjie Ruan , catalin.marinas@arm.com, will@kernel.org, oleg@redhat.com, tglx@linutronix.de, peterz@infradead.org, luto@kernel.org, shuah@kernel.org, kees@kernel.org, wad@chromium.org, charlie@rivosinc.com, akpm@linux-foundation.org, ldv@strace.io, macro@orcam.me.uk, deller@gmx.de, mark.rutland@arm.com, efault@gmx.de, song@kernel.org, mbenes@suse.cz, ryan.roberts@arm.com, ada.coupriediaz@arm.com, anshuman.khandual@arm.com, broonie@kernel.org, pengcan@kylinos.cn, dvyukov@google.com, kmal@cock.li, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20251126071446.3234218-1-ruanjinjie@huawei.com> <20251126071446.3234218-12-ruanjinjie@huawei.com> <8c55c2a1-995e-44a1-8d48-b7d794f5176f@arm.com> <0e65df65-c454-df7f-0685-42e9c0f0f9e3@huawei.com> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: <0e65df65-c454-df7f-0685-42e9c0f0f9e3@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 29/11/2025 02:23, Jinjie Ruan wrote: >>>>> #define TIF_UPROBE 5 /* uprobe breakpoint or singlestep */ >>>>> #define TIF_MTE_ASYNC_FAULT 6 /* MTE Asynchronous Tag Check Fault */ >>>>> #define TIF_NOTIFY_SIGNAL 7 /* signal notifications exist */ >>>>> -#define TIF_SYSCALL_TRACE 8 /* syscall trace active */ >>>>> -#define TIF_SYSCALL_AUDIT 9 /* syscall auditing */ >>>>> -#define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint for ftrace */ >>>>> -#define TIF_SECCOMP 11 /* syscall secure computing */ >>>>> -#define TIF_SYSCALL_EMU 12 /* syscall emulation active */ >>>>> +#define TIF_SECCOMP 11 /* syscall secure computing */ >>>>> +#define TIF_SYSCALL_EMU 12 /* syscall emulation active */ >>>> These seem to have reappeared in v8 for some reason? >>> v8 add "ARCH_SYSCALL_WORK_EXIT" to be defined as "SECCOMP | SYSCALL_EMU" >>> to keep the arm64 behaviour unchanged as mentioned in v7. >> Ah then that is where the issue is, I missed that: surely switching to >> generic entry means that we are using SYSCALL_WORK_BIT_* rather than >> TIF_* for all these flags? > I think they may be the same thing as you mentioned in v7，neither > SYSCALL_WORK_EXIT nor report_single_step() excluded SYSCALL_EMU, maybe > we should clarify them for arm64 together in a separate patch. These two might indeed be related. On second thoughts, while waiting for more knowledgeable arm64 reviewers, I would suggest aligning arm64 with the generic entry. Which means... > 1、"The generic report_single_step() always returns false if SYSCALL_EMU > is set." ... replicating this behaviour on arm64 (in a separate patch), and... > 2、" > > -void syscall_exit_to_user_mode_prepare(struct pt_regs *regs) > > -{ > > - unsigned long flags = read_thread_flags(); > > - > > - rseq_syscall(regs); > > - > > - if (has_syscall_work(flags) || flags & _TIF_SINGLESTEP) > > I believe switching to the generic function introduces a change > here: syscall_exit_work() is only called if a flag in > SYSCALL_WORK_EXIT is set, and this set does not include SYSCALL_EMU and > SECCOMP. Practically this means that audit_syscall_exit() will no > longer be called if only SECCOMP and/or SYSCALL_EMU is set. > > It doesn't feel like a major behaviour change, but it should be > pointed out." ... replicating this on arm64 as well, i.e. introducing a separate set of flags for syscall exit. This should be a patch of its own, as it isn't directly related to the report_single_step() behaviour (especially since it concerns SECCOMP as well). It would also be an occasion to get rid of has_syscall_work(), in preparation to the move to generic entry. - Kevin