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 46EA238BF8B; Fri, 20 Mar 2026 11:44:27 +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=1774007069; cv=none; b=WjuJulBIr+pY25cLM3X96b5eHsNoMLGXSurdsjZY0b1rN8h3Z3tstQqeCiPFNRhrzepFTr5VqtVuJ9A64c5yUlGL5tKecAuDCzSjDavSeHMIa7Zv1TuBLr/rIQZ6A1onQrd6ImXoGOdC0akr+a/jrWRjx/0Qch+yNzqP2APq1yc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774007069; c=relaxed/simple; bh=hArs6kuS6KydQwdlUptQjuqRWQ1FvnPZM7ZYZf/TLrk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZBzR1URDlyAVZl/Bsky4l2FH8cIWE5OM6ncaYMNVJXKv7uPyR6Lpy6n8Yjm8uh4GdgmgTiJJ4XaXKq1kCtVwF7kCjBU3TR7iACxYUx7j57R/PBXjoIXsQHRd2pyOh9745S3bJ8vYzD/0yUM+/1OYXvarpEwyfsqmrw5E/0Gt/7c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (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=YqxYl0Jr; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (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="YqxYl0Jr" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=05LtVHDNFjk2gcHE0LjqHjkm1UfXVzvSZfD5gJyPASA=; b=YqxYl0JrNguL8FYvIt586nPwqi hufFUS0Orf+rBIunwY3lw6HbNbS6x8hyohUPMGaWTL4XRrOW7OBaAxVcrzLQspcibzH9XSH+26rsv ebjN8atQ/5jVoJCM/aOKK1cl+zKFMkXWY6Cnbpm4XrkA2LpsKJc5uOImVQvwVFZR4bkSpJJQkEkd+ 0WP/2o2NdyUu3Bj6ejK270tmWr8Q5Ft0k4PTNfgGQJKXO6GqtFAHD3wVSbazwOU4/CWhAlkr+w7cm PeB47eRWpDclVcWccYOeeJv3ZVb38g5kF9QkLAMSh8D5gM1P9vK5OstWHm76GxSAMHFigSDwfyJrq 8DCL2ToQ==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1w3YHB-0000000FT4q-0NAV; Fri, 20 Mar 2026 11:44:25 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id C5616300578; Fri, 20 Mar 2026 12:44:23 +0100 (CET) Date: Fri, 20 Mar 2026 12:44:23 +0100 From: Peter Zijlstra To: Heiko Carstens Cc: Alexander Gordeev , Sven Schnelle , Vasily Gorbik , Christian Borntraeger , Juergen Christ , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: Re: [PATCH v2 0/9] s390: Improve this_cpu operations Message-ID: <20260320114423.GC3558198@noisy.programming.kicks-ass.net> References: <20260319120503.4046659-1-hca@linux.ibm.com> <20260319135612.GI3738786@noisy.programming.kicks-ass.net> <20260320113909.9681Aad-hca@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260320113909.9681Aad-hca@linux.ibm.com> On Fri, Mar 20, 2026 at 12:39:09PM +0100, Heiko Carstens wrote: > On Thu, Mar 19, 2026 at 02:56:12PM +0100, Peter Zijlstra wrote: > > On Thu, Mar 19, 2026 at 01:04:54PM +0100, Heiko Carstens wrote: > > > v2: > > > > > > - Add proper PERCPU_PTR cast to most patches to avoid tons of sparse > > > warnings > > > > > > - Add missing __packed attribute to insn structure [Sashiko [2]] > > > > > > - Fix inverted if condition [Sashiko [2]] > > > > > > - Add missing user_mode() check [Sashiko [2]] > > > > > > - Move percpu_entry() call in front of irqentry_enter() call in all > > > entry paths to avoid that potential this_cpu() operations overwrite > > > the not-yet saved percpu code section indicator [Sashiko [2]] > > > > Would it make sense to add arch hooks to irqentry_{enter,exit}() ? > > I guess it would make sense to have some architecture hook which > allows to run code on all entry/exit paths instead of duplicating the > code n times. > > But apparently my code seems to have more bugs (e.g. I didn't consider > kprobes which would make the instruction comparison not work). So this > has to wait until I'm back after vacation. My vote is to reject kprobes in these regions :-) Anyway, enjoy the time off!