From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 11E481A314E for ; Fri, 15 Aug 2025 10:59:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755255554; cv=none; b=h8VL3ol/qA2HZrqZZ1wFX2ZzwFkTwFb6wjStRgc2zDJfmdz9wrefdezLZnS2+J0sPt3EUSb2DllBIK0G9uAgrcyCJdpS0HlHUmPxMnZSof8ruFFFgLWNC8FjAjEiygIhE4EG47VgGxt6ri2GSa/t8jYTplg4E6yXZQ6SHcXq1I0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755255554; c=relaxed/simple; bh=g0/O1iYV+SZ8B/ewpSUxw+zPzI1yvyyAsucYOb1skZ8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=R+fXJKIufU2BMorLdN/pc9JFvYhSKjQemDUY76+PMZ2fLZmAMDewoP0eDNtJfRn5QkL+L2oqNMZ3AEV2vpwLQHki0S3qEnAmdFob64qLJjTHZTmtdq0Bq9MpOhVKxeF3/EEE4HZM4ea1J7gzC6AqCKAyNLonMn53cij4c91C37c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=fiuzuayc; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="fiuzuayc" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=xEYKs+AWtTrvQAx9SeWmZ/00cM/6CAdp0sRjPofAC/k=; b=fiuzuayczJS+Z/C7Bci5K50RMb 3rElw6OaiWacdOq8bIbE+8JNAJYsggKicDjDv2DkZ5sSLvtNbEl5g4/QwpVcpj16FRsZYseRNQoAL PjkoCz8HqyX+2oV8C1expR59hta+WwAsqDWBoRNkZic4y3LugPJunwMIrkhFWEKvFtAU5wunqVxhG ezIJs11PAD7l05j0heHWPDXwVEjq8/Zg51vpLBsK4LL7Fz7sv8DfPb3C3KFXgK/D+l7UQaBJMNvDB Ua6owOzZeqydVKNoNtvHyyMiLlflMjdGOc1CCplPn9wnhuKq4DkYkSR9NgqSFCVv2AgSxjOinMsed QF4KHcHg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1ums9N-0000000Ggds-3Esk; Fri, 15 Aug 2025 10:59:10 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 125DE3002ED; Fri, 15 Aug 2025 12:59:09 +0200 (CEST) Date: Fri, 15 Aug 2025 12:59:08 +0200 From: Peter Zijlstra To: Andrew Cooper Cc: "H. Peter Anvin" , x86@kernel.org, kees@kernel.org, alyssa.milburn@intel.com, scott.d.constable@intel.com, joao@overdrivepizza.com, samitolvanen@google.com, nathan@kernel.org, alexei.starovoitov@gmail.com, mhiramat@kernel.org, ojeda@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH] x86,ibt: Use UDB instead of 0xEA Message-ID: <20250815105908.GB3245006@noisy.programming.kicks-ass.net> References: <20250814111732.GW4067720@noisy.programming.kicks-ass.net> <2c121572-8fde-4288-80ca-ab79f2b22cce@zytor.com> <20250815074939.GA3419281@noisy.programming.kicks-ass.net> <20250815102839.GD4068168@noisy.programming.kicks-ass.net> <20250815103055.GE4068168@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Aug 15, 2025 at 11:43:11AM +0100, Andrew Cooper wrote: > >> I've had to use cs prefixed jcc.d32, because our older toolchains don't > >> like the ,pn notation. > > And then I forgot to move that cs prefix around in the bhi1 case... > > fixed that. > > Dare I ask what ,pn notation is?  It's not only the older toolchains > that don't know it :) Some fancy notation for the CS/DS branch hints. CS Jcc, decodes to Jcc,pn for non-taken DS Jcc, decodes to Jcc,pt for taken