From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1F069F5A8AB for ; Mon, 20 Apr 2026 18:49:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qNcjPWzH/6/oNRqggcjbcb7DOm2Qg8QluDQNeeHntFQ=; b=BS2GEEZATJ5RE25HU3NMrRVIg1 6z748GSGKqkPNDkHJiebPjkBwYyjoyzIRM0P6Ne7hk2yhaHdM7LhM5O1Kod0LcqEkpTbYve4I9wDe dO9BmRCxtOMBnjWFbxBQLDiNGQwZWnRHccgv3ycp4+9TSgqnsPFwVfjAAMUYmuUdAINdVyIjhmEll MtPEoq6dOjdL4OWpBcdeciPYw51SoiNdARXu5GA6WNrfJqTgJ5v9XHYRwDf9S3GKTOYahqrOdx6gv DLnTn7fknDvmbztrvSQ6Gf2GgA4Z8N5pv6VvxPnR0QKvqiFKPjuCaZQBOWhTIoh+WTFu6kfh+lCw/ 9aPSeEgg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wEtgL-00000007Ysw-3eTZ; Mon, 20 Apr 2026 18:49:17 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wEtgJ-00000007YsT-0Csg for linux-arm-kernel@lists.infradead.org; Mon, 20 Apr 2026 18:49:16 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id B2B744435A; Mon, 20 Apr 2026 18:49:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0FC9C19425; Mon, 20 Apr 2026 18:49:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776710953; bh=QHMzHRcLV1R2QvWX77MHFvc7Z/WhIck+SfReGrL2CiA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ozVwLVWtbbv1dAM7yazhYlk9vBe+pKM2xJQmU3CiYqNJsEr7tzkK6TWdMIXiJlWlf Xi0Gr58XdKl+3sujWzhDdtlzNzkBwE5zzpUG2Ql0vQmCymqK/xC5KY3I8Riknd/8pt 8lkOHH2ydXVU5JhblmB7Rj/oOzBBE4/+qkTHM0WYQxKgAfsglgKPYf59suelKyClVR cLaIBFMEPbb8ftZykqjauwGJAPzMzHveyDuG+uT4/k8TXjSBUZRmbPtyN98cvN9rky J8QnLPwrNrYd5t51NQFAXwcftF7jzJsXozYUHNaRxaE8Wp4lrmHOUWSN0S7VgKyALv 3SQB8ubcc9iuw== Message-ID: Date: Mon, 20 Apr 2026 20:49:02 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 01/30] mm: Introduce kpkeys To: Kevin Brodsky , linux-hardening@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , Ira Weiny , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Lorenzo Stoakes , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , Quentin Perret , Rick Edgecombe , Ryan Roberts , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org References: <20260227175518.3728055-1-kevin.brodsky@arm.com> <20260227175518.3728055-2-kevin.brodsky@arm.com> <00b24db8-0063-48d6-8bc4-e8b670d8f0d5@kernel.org> <913002a5-e002-4001-ad19-037102d1f97d@arm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260420_114915_130951_223E8A21 X-CRM114-Status: GOOD ( 20.02 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 4/20/26 08:46, Kevin Brodsky wrote: > On 17/04/2026 19:38, David Hildenbrand (Arm) wrote: >> On 4/17/26 17:59, Kevin Brodsky wrote: >>> The first two are not meant to be directly called, they're the >>> arch-specific implementation of kpkeys_set_level() and >>> kpkeys_restore_pkey_reg(), and those generic functions handle some >>> generic logic. >>> >>> arch_kpkeys_enabled() is directly used in generic code, so I suppose it >>> could be renamed to kpkeys_enabled()? It's actually implemented in an >>> arch header so I wasn't too sure about it. >> I was skimming over patch #13 and spotted: >> >> +void·__init·kpkeys_hardened_pgtables_init(void) >> +{ >> +› if·(!arch_kpkeys_enabled()) >> +› › return; >> + >> +› static_branch_enable(&kpkeys_hardened_pgtables_key); >> +} >> >> The arch_* there can just go IMHO. >> >> I'd also do it for the two ones used by the GUARD macros. If we don't >> expect common code wrappers (arch_kpkeys_enabled() vs. kpkeys_enabled), >> then the arch_ is unnecessary information -- IMHO > > Makes sense. I could just rename arch_kpkeys_enabled() to > kpkeys_enabled(), but I'm thinking having an arch abstraction could be > clearer, after looking into protecting sparse-vmemmap page tables. The > new version would look like this: > > * : >     - arch_supports_kpkeys() >     - arch_supports_kpkeys_early() [can be called before features have > been detected] > > * defines: >     - kpkeys_enabled() -> arch_supports_kpkeys() >     - kpkeys_hardened_pgtables_enabled() -> static key >     - kpkeys_hardened_pgtables_early_enabled() -> > arch_supports_kpkeys_early() [called when setting up sparse-vmemmap, > linear map, etc.] > > There is extra #ifdef'ing going on in , but > doesn't need to worry about it. I think this might be > easier to follow, I don't like too much having an interface function > like kpkeys_enabled() defined in an arch header (not great for > kernel-doc comments either). Any thoughts? No strong opinion on the indirection as long as we don't call arch_ stuff from ordinary pkey user code :) -- Cheers, David