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 EEB9727381B for ; Thu, 25 Sep 2025 23:17:27 +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=1758842248; cv=none; b=QkTGh2zxLaK85aznzV59lVsEwVISbggLKSERYGznRbbpeDpsfwFclufOk+xtwx6J5gDeXB/6v/QinDTbJtsS2B8O+O3Zz40jN3E8KaP9sIzZItOt6WZJsOHeWUPxGWh0LYvHuaV+6xryTSFVQKecPWhHxMCu8WPNCP4bezAqpzA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758842248; c=relaxed/simple; bh=UwBJHVT+vWTJwWZDgObwFp0nU7Jl8uwGl6zSa7Yy8ow=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=G3Aps99EP/0P6x8xfSf+/KuH/vxRXJbPr0O4o1rewNfHxXxUGBTjGR1rCShelgUSrGkaP0eWKyl01QmaHayp46NaFTETK+RKIecoyrGVGfLJKVWS5+Iq7uOfKT1HEGglrf+kQa0NAoH6nNZ7U7IDGKHIX/VXnj+1YDbG9IDRWqk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=zEu5uNbk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="zEu5uNbk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17829C4CEF0; Thu, 25 Sep 2025 23:17:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1758842247; bh=UwBJHVT+vWTJwWZDgObwFp0nU7Jl8uwGl6zSa7Yy8ow=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=zEu5uNbkHJ/tF/idnqJzhDukNEJsCLAt/cqSv6tmmHekUCwoTCaP46y0WDQiNW87L ipPmAS3ipMBid93CHivs8o7CJ8NPaK7SW3j3hOyNv/GBxiPdQBauzCuvQGhxuJj74A Acuptcch5exZ/orzwU4SsPt32okZe7NaXtlVer38= Date: Thu, 25 Sep 2025 16:17:26 -0700 From: Andrew Morton To: Andrew Donnellan Cc: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, pasha.tatashin@soleen.com, sweettea-kernel@dorminy.me, nicholas@linux.ibm.com, christophe.leroy@csgroup.eu, alexghiti@rivosinc.com Subject: Re: [PATCH v17 00/12] Support page table check on PowerPC Message-Id: <20250925161726.2b34890070e6d8dcf8ad3ba9@linux-foundation.org> In-Reply-To: <336c0402c59363956d0c4eefc1b8a059e1fcc8e4.camel@linux.ibm.com> References: <20250909091335.183439-1-ajd@linux.ibm.com> <336c0402c59363956d0c4eefc1b8a059e1fcc8e4.camel@linux.ibm.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 26 Sep 2025 08:42:35 +1000 Andrew Donnellan wrote: > On Tue, 2025-09-09 at 19:13 +1000, Andrew Donnellan wrote: > > Support page table check on all PowerPC platforms. This works by serialising > > assignments, reassignments and clears of page table entries at each level in > > order to ensure that anonymous mappings have at most one writable consumer, > > and likewise that file-backed mappings are not simultaneously also anonymous > > mappings. > > > > In order to support this infrastructure, a number of helpers or stubs must be > > defined or updated for all powerpc platforms. Additionally, we separate > > set_pte_at() and set_pte_at_unchecked(), to allow for internal, uninstrumented > > mappings. > > > > On some PowerPC platforms, implementing {pte,pmd,pud}_user_accessible_page() > > requires the address. We revert previous changes that removed the address > > parameter from various interfaces, and add it to some other interfaces, > > in order to allow this. > > > > Note that on 32 bit systems with CONFIG_KFENCE=y, you need [0] to avoid > > possible failures in init code (this is a code patching/static keys issue, > > which was discovered by a user testing this series but isn't a bug in page > > table check). > > > > (This series was initially written by Rohan McLure, who has left IBM and > > is no longer working on powerpc.) > > Is this likely to make it in in time for 6.18, or should I respin it post merge > window? The latter, please.