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 446FD1BD9F3; Tue, 19 Nov 2024 23:39:05 +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=1732059546; cv=none; b=MFr0GCZX8vp5744bM1mFd3BweJesG8WboEqgBnKqWScwkmOM7vZGWjlRMudL+CQ7ytnq5zq/EqmdQJAKCoC1XPp64AHegUdIWcgN0rmyoxVVhovX/A3ju9MNIbwM7ottApPbSoFGNeHGF1upX1iLNe99qdYVgsNis0M2J6Q5mLk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732059546; c=relaxed/simple; bh=MJi3Fv2/1QvfWr/LiwMdd8vo0kHoZwkP7YNG7EQREfw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hoig5TnPxVlZh6uu3DCTcpWYZESUUUy2LC+rtDstKR3/KsE9uoL4koFpJKip7wDYo4md4bSKuQwydwYC979hAybvUSMKrHYevHtXYf5FETuTW6gUY3rKKkGXrYtCVB5AIVatJsmSBkJkjfKgP4WqlqckyD49hGZnnFzjPcPnhFk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VVwSwoDN; 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="VVwSwoDN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB9B3C4CECF; Tue, 19 Nov 2024 23:39:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732059545; bh=MJi3Fv2/1QvfWr/LiwMdd8vo0kHoZwkP7YNG7EQREfw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VVwSwoDNu1TqMFW15ochzl8vEFTrIMSh2sexLA6XSHJ6qClpYzQmx/p8q0+V/ICdK QcTGJLa+7qQQT24Pg/o/ujB9zzGyzPLCSBycIpzaqRQmmnJgp8Bmm/Asv7c/PmvwiR hos+7CVCbsa55k1mc7GHNj+kA8fGiX99G6or+53fRDs2TtOHAVH3KebnDSKX5Yyt/J L+g+8gDhlLq8+G9Zy9kb7DEd1lIcrJQYolbFdsAW5Kbk4+ktaecXpi0xWOSpdFxTtO qI8NUGX2AHe6987zz7E0iSHgJlM8A9RAr5kj/WxICexja0uizSdnkHYiGVUCbPB9TB izDxUiUHmBDCA== Date: Tue, 19 Nov 2024 15:39:02 -0800 From: Josh Poimboeuf To: Valentin Schneider Cc: 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 , Peter Zijlstra , 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 =?utf-8?Q?Wei=C3=9Fschuh?= , 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: <20241119233902.kierxzg2aywpevqx@jpoimboe> References: <20241119153502.41361-1-vschneid@redhat.com> <20241119153502.41361-7-vschneid@redhat.com> 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=utf-8 Content-Disposition: inline In-Reply-To: <20241119153502.41361-7-vschneid@redhat.com> On Tue, Nov 19, 2024 at 04:34:53PM +0100, Valentin Schneider wrote: > Later commits will cause objtool to warn about non __ro_after_init static > keys being used in .noinstr sections in order to safely defer instruction > patching IPIs targeted at NOHZ_FULL CPUs. Don't we need similar checking for static calls? > Two such keys currently exist: mds_idle_clear and __sched_clock_stable, > which can both be modified at runtime. Not sure if feasible, but it sure would be a lot simpler to just make "no noinstr patching" a hard rule and then convert the above keys (or at least their noinstr-specific usage) to regular branches. Then "no noinstr patching" could be unilaterally enforced in text_poke_bp(). > diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h > index f5a2727ca4a9a..93e729545b941 100644 > --- a/include/linux/jump_label.h > +++ 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 JUMP_TYPE_NOINSTR_ALLOWED ? -- Josh