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 313B9EFB811 for ; Tue, 24 Feb 2026 08:23:57 +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:Mime-Version:References:In-Reply-To: Message-Id:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=iizpfzio0v/iDnU/1NLHbWCsyqKgQ3UFSP5S6pHOju8=; b=ACCboG0/FfpmQi 6mt1WCPu7AhVb7Rir1UU6l87fYB9nRDK3iSc6ay7WX5jrFWHQ4SuTwM5MtlAA4nQzPE5PXvfRwuHg qbpJJn+Opt+BOqTOiPaMaOzX43AVrGl0ZbJAHb4UtkoPQCUB8d4qrTv2ddMUoG4RGZKBYSvqywIph vvWsQH5vjrx2VOIAn0NLoBmsH66jg88NeiutXPCKqUW7R2dgYlAaRCefqLsJPODrnsYnAf+9Cf++3 G7ga2SMKSrdrlYnpaNoB/RnmKw7+4/TuC5l4HwvFrfeswd9xzrHcOIafqpeMOgxcFB7ARPUZUVy1k 1ZeA5tDPCImJQ/BXp2oQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vunhv-00000001dZR-48jT; Tue, 24 Feb 2026 08:23:51 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vunhu-00000001dZH-2x7h for linux-arm-kernel@lists.infradead.org; Tue, 24 Feb 2026 08:23:50 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id D5E40600CB; Tue, 24 Feb 2026 08:23:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E176C116D0; Tue, 24 Feb 2026 08:23:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771921429; bh=yW/XdX7C6OB/JJmDVlyglpXhjr79lcN8BLHSEqmvmuw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=cpx6cgZql3OwQ/HJCQrsGktvOyjDIU47oLrJ4zVE+Ubk8lQBV/R9eo0107OvLJmIT roM6sWuHUryAPLCGIugNxqV4ptPnsT5YEcnOTsruUM9QWg0zkXwVPlCO/zdKfJniQ5 yEWn5ketwoDlGyBemeLEemHxdcQssoZhutw8nN1PitISkwNx+rAnFQWmqbQ1xTPARH 5znb2xfgDnRI94BHc77IG6Exdx46ShMh914oWmr8Tjvuz2hGe8UK0zZFQS3Gtu5QmH cQznkVTt0t1t10c0gFdoUA/+E1DWEVEosXP0M6yIdK3e0Tzsqip84sWbdFOW2fqhrH 6Iz53NCvwyDtg== Date: Tue, 24 Feb 2026 17:23:46 +0900 From: Masami Hiramatsu (Google) To: Mark Rutland Subject: Re: [PATCH v2 2/2] arm64: insn: drop NOP from steppable hint list Message-Id: <20260224172346.9f094cffc58ce7e013a4d7c2@kernel.org> In-Reply-To: References: <20251106104955.2089268-1-khaja.khaji@oss.qualcomm.com> <20260217133855.3142192-1-khaja.khaji@oss.qualcomm.com> <20260217133855.3142192-3-khaja.khaji@oss.qualcomm.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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: catalin.marinas@arm.com, dev.jain@arm.com, linux-kernel@vger.kernel.org, mhiramat@kernel.org, linux-arm-msm@vger.kernel.org, yang@os.amperecomputing.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, Khaja Hussain Shaik Khaji Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 17 Feb 2026 16:57:08 +0000 Mark Rutland wrote: > On Tue, Feb 17, 2026 at 07:08:55PM +0530, Khaja Hussain Shaik Khaji wrote: > > NOP is already handled via instruction emulation and does not require > > single-stepping. Drop it from aarch64_insn_is_steppable_hint(). > > > > Signed-off-by: Khaja Hussain Shaik Khaji > > --- > > arch/arm64/include/asm/insn.h | 1 - > > 1 file changed, 1 deletion(-) > > > > diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h > > index e1d30ba99d01..9429f76906e0 100644 > > --- a/arch/arm64/include/asm/insn.h > > +++ b/arch/arm64/include/asm/insn.h > > @@ -456,7 +456,6 @@ static __always_inline bool aarch64_insn_is_steppable_hint(u32 insn) > > case AARCH64_INSN_HINT_BTIC: > > case AARCH64_INSN_HINT_BTIJ: > > case AARCH64_INSN_HINT_BTIJC: > > - case AARCH64_INSN_HINT_NOP: > > return true; > > default: > > return false; > > The intent is that aarch64_insn_is_steppable_hint() says whether an > instruction is safe to step, not whether it *must* be stepped. I think > we can leave NOP here unless this is causing some functional problem? Agreed. I think we should keep this as it is. Thank you, > > Mark. > -- Masami Hiramatsu (Google)