From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CB9932749E6; Tue, 24 Feb 2026 08:23:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771921429; cv=none; b=maBDRQOVO/9BgwnYxKp8vWQcwFDMliKsfnfanwFl8YrmOQmV7LLP2VN9Y+X/8G2y3SN83QAg4lt4ia+S5qGJW5vtPBMzQas/vrHLbcJdbmOkHnwbiLTLu54uAM8gRwHCu2HC/wQ7AlQ3x0k6Sx7G4SrhRDKhP1ipcZUUUwWw5Ms= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771921429; c=relaxed/simple; bh=yW/XdX7C6OB/JJmDVlyglpXhjr79lcN8BLHSEqmvmuw=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=CJnuuTw3aQWdrGHehTuLEmlowpJ8PYzSmDeUF9SzqhEXAx3o/fUQ7oOIpzeBz5dPwxv2ESwpg4G7oUvbyM3cmjl2Y4Y7ljs7dhvK3EIUyCWbpaNGFezRRVvQPkTSTBKMFov9PlENTxhTecSVwTO7P0N/huzPhJmMUZl5toGtxQU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cpx6cgZq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cpx6cgZq" 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 Cc: Khaja Hussain Shaik Khaji , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, mhiramat@kernel.org, yang@os.amperecomputing.com, dev.jain@arm.com, ada.coupriediaz@arm.com, linux-arm-msm@vger.kernel.org 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) Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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)