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 2DC7DC531F8 for ; Thu, 23 Jul 2026 16:38:36 +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=CUO8C4g2gaArh4Y4Dlt29OXXWCzGAsxU5Y8v+yOgtp0=; b=uf9r+XjZUeltp8kU7a6SgxTBzD aPk5tvRsOp6Rxmc/5ez2/tkFgjpAGk2HdDQBkmy71RXh8yPNos2Hhdh6bb9963ZaljghGxT+pw3ub WE9bIfrr/EFZC9DYjGbu5B529fvDdV71VQ1GEhfZuVJt9FE4U4+S/hLPRLqIsZW0gZUXzqD2MMAm/ iE3cfbcCBnLs0u0yEIVTo1oHs21yvmpcMwWkHoobKFtoMZpvMKhEMzUCw/UcAKUvzIa/gbISXJ+EV SbltPevgoYDixHRgS/p6RlognjxxnqZPs4B2JKSfut3lkg38vijSiwX60VxNl4ydGf3ToTI421nrO kQEWCZTQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wmwRJ-0000000Ejfn-0gDB; Thu, 23 Jul 2026 16:38:29 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wmwRH-0000000EjfJ-3prz for linux-arm-kernel@lists.infradead.org; Thu, 23 Jul 2026 16:38:28 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id C2FCA60A58; Thu, 23 Jul 2026 16:38:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 155ED1F000E9; Thu, 23 Jul 2026 16:38:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784824706; bh=CUO8C4g2gaArh4Y4Dlt29OXXWCzGAsxU5Y8v+yOgtp0=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=CeMVKs5XYRbmdHnZWBRbIOqlnBLNOn4YY2wMWAwayfNfMto7y/YliPtgQRBpZUmTT vr19Tp4i8Wn8VkHl+4XE9zaPN4O1GKjEX2pMXsObb21kIktQoVMW4AxauYM7mFqsqy m9Vfa5aIPEAoUj2XLgE811bhN1BpHteetKbAGL5fm88oTXU8xJ0uJTDJgsw5Cdqvvv 3kfPW67BOYQdcVgtsWd02pt9jPfjCc1B1jL3Qe4VFfPdK2ERG3xSGp2d2kucltgaZ4 tsbkuGb4ZFTZOHIRVYEoFAE0PsnhkIQB2+/JG5y2b3OGNsB5jMcgjpaLsNqzciGxke LIL16JRMH+F/Q== Message-ID: <716f73c1-41cc-48a5-b0e1-a47403a30da1@kernel.org> Date: Thu, 23 Jul 2026 18:38:02 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: mm: opaque hardware page-table entry handles To: Muhammad Usama Anjum , Alexander Gordeev Cc: Zi Yan , Pedro Falcato , Ryan Roberts , Lorenzo Stoakes , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Andrew Morton , "Liam R. Howlett" , Mike Rapoport , Anshuman Khandual , Catalin Marinas , Will Deacon , Samuel Holland , linux-s390@vger.kernel.org References: <74182e50-b54f-4d2d-a27f-3a59a538d6bc@arm.com> <31d36023-d728-4eee-90f8-158c7066f565@kernel.org> <4bfeb697-9c1f-4316-96bb-9bfd66f959df@kernel.org> <6110202c-057b-4701-8c04-1a76ee7bb9ab@arm.com> <20260721124057.2820903Adf-agordeev@linux.ibm.com> <3c21586c-0ffe-4ebc-97f1-803e8acfc5c1@arm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <3c21586c-0ffe-4ebc-97f1-803e8acfc5c1@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit 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 > So after the conversion, it doesn't makes sense to keep STRICT_MM_TYPECHECKS > around. Please correct me if I'm wrong. > > This brings another thing in my mind that in ideal world we would just > turn STRICT_MM_TYPECHECKS on for all arches all the time. But the problem > with it is that STRICT_MM_TYPECHECKS defines pte_t which will stay double > meaning still. So we want sort of STRICT_MM_TYPECHECKS with different name > and separate stack and hardware types. I think STRICT_MM_TYPECHECKS is also to avoid catching when passing a pte_t into a function that consumes a pmd_t, and vice versa. STRICT_MM_TYPECHECKS makes the compiler generate worse code today, which is why we don't enable it always. > >> >> We would like to keep it, and I guess some other architectures too. > David had summarized it well. We'll convert generic code to use hw_p*_t > types which would be typedef to p*_t for those architectures which don't > care about. But if an architecture wants to interpret these types > differently or want to make sure the type is enforced and not directly > dereferenced, they need to convert the arch code a well. But it can be > done slowly. I think what Alexander meant is: they want to keep STRICT_MM_TYPECHECKS (or something that achieves something similar :) ). So as long as that keeps on working, all good :) -- Cheers, David