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 17F4C174EDB for ; Wed, 20 Nov 2024 10:22:58 +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=1732098180; cv=none; b=NlSptyoA0dOgxhU7W/5NHeFeh5mspjfdKAtG3UqgdPoHvF6diNaphVcyNhpUO4W8KNs5prFLZ3r7flmkNY+uHVkZrU3rCDlkAMMNPJILh7d7zCrPCZMw5q9K8am503DF9Gn19g5tDrB6SKsPwWJZ07Zfz8JBnP64CdvlYVIbVY0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732098180; c=relaxed/simple; bh=kJQDEeMh5yQymd7/4zNyXAyvNMvAn8pbTvK9MW3F1j4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=C8iOJ4AicpWCO+Tga7G8j4DQtYxKG/oM96aNW8O0XisBCk/SXZKgfuIhjft6yMol9xIIhnn1MNq5YHI8pPf4V3WojzzsFto27U2DulHPnQouVpbSkmjGRd1VSgIYTcB+pRKhwrfjaA9dTTZJjUTWvK8sIK7oAajCzm3Rf4irVwc= 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=CB9pfzxo; 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="CB9pfzxo" 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=6BHYRXy9lLaaBbd09VImTq6Rn50W4X4567EqZRkeTsQ=; b=CB9pfzxoXqNdnea45S13GW9nVz OiMmlRet2bv4yQjYfZUir1rmaicloAg0pVBGRuIjsJ086tAjDiP5d/vkTpeM7AdCzbuPdOcLgtTnf 16s9gXgpwYsh0BYhQP/YIP8EUR/oQjVbi18ayEvx7NktKnB+cttBWZOrefugTlVa8jpZ9p2lTqXlw 38U5AEbLbyu0v+ssq8oub7kzzElAb/wUORNzUz9cQXeRTJh0QxuvPxaNrjHqkzi8SYaz/lSntiay3 SPIHCBEOosL4kWT3+2JRT04nREsm8heOOUdOgkm90wTxYr1oUWty25O1g2tuDCZcAxfyVPCYQKJiW kM7zG+ZQ==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tDhqm-00000000SnB-3qXl; Wed, 20 Nov 2024 10:22:21 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 04D013006AB; Wed, 20 Nov 2024 11:22:20 +0100 (CET) Date: Wed, 20 Nov 2024 11:22:19 +0100 From: Peter Zijlstra To: Josh Poimboeuf Cc: Valentin Schneider , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, x86@kernel.org, rcu@vger.kernel.org, linux-kselftest@vger.kernel.org, Steven Rostedt , Masami Hiramatsu , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Andy Lutomirski , Frederic Weisbecker , "Paul E. McKenney" , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Lorenzo Stoakes , Jason Baron , Kees Cook , Sami Tolvanen , Ard Biesheuvel , Nicholas Piggin , Juerg Haefliger , Nicolas Saenz Julienne , "Kirill A. Shutemov" , Nadav Amit , Dan Carpenter , Chuang Wang , Yang Jihong , Petr Mladek , "Jason A. Donenfeld" , Song Liu , Julian Pidancet , Tom Lendacky , Dionna Glaze , Thomas =?iso-8859-1?Q?Wei=DFschuh?= , Juri Lelli , Marcelo Tosatti , Yair Podemsky , Daniel Wagner , Petr Tesarik Subject: Re: [RFC PATCH v3 06/15] jump_label: Add forceful jump label type Message-ID: <20241120102219.GF19989@noisy.programming.kicks-ass.net> References: <20241119153502.41361-1-vschneid@redhat.com> <20241119153502.41361-7-vschneid@redhat.com> <20241120000532.maqzgsn7m34lti6u@jpoimboe> Precedence: bulk X-Mailing-List: bpf@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: <20241120000532.maqzgsn7m34lti6u@jpoimboe> On Tue, Nov 19, 2024 at 04:05:32PM -0800, Josh Poimboeuf wrote: > On Tue, Nov 19, 2024 at 04:34:53PM +0100, Valentin Schneider wrote: > > +++ b/include/linux/jump_label.h > > @@ -200,7 +200,8 @@ struct module; > > #define JUMP_TYPE_FALSE 0UL > > #define JUMP_TYPE_TRUE 1UL > > #define JUMP_TYPE_LINKED 2UL > > -#define JUMP_TYPE_MASK 3UL > > +#define JUMP_TYPE_FORCEFUL 4UL > > +#define JUMP_TYPE_MASK 7UL > > Hm, I don't think we can (ab)use this pointer bit on 32-bit arches, as > the address could be 4 byte aligned? Right, you can force the alignment of the thing, workqueues do similar hacks to get more bits.