From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E0B6B606A321 for ; Mon, 9 Nov 2026 14:04:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=dZ5s8tEn Received: by kanga.kvack.org (Postfix) id E6B066B05B5; Mon, 9 Nov 2026 09:04:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E43556B05B7; Mon, 9 Nov 2026 09:04:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D31EB6B05B8; Mon, 9 Nov 2026 09:04:42 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id AD3A36B05B5 for ; Mon, 9 Nov 2026 09:04:42 -0500 (EST) Received: from smtpin25.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 495FAA8335 for ; Mon, 9 Nov 2026 14:04:42 +0000 (UTC) X-FDA: 85415751204.25.E3109C1 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf01.hostedemail.com (Postfix) with ESMTP id 529FB40016 for ; Mon, 9 Nov 2026 14:04:40 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=dZ5s8tEn; spf=pass (imf01.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1794233080; b=7hejRRU5xsPIIYMoCHUF0tLSI87SO2jbeQyw7qrl7o0G9tJ1GNP9o41PZzbP1z4zkinJLT 82B6arSA43iNiFkCuDkWl1MzqTnoQo1hQ8BiSob4fmcdPJ48prVT9F4M5qsFfUAESr3kFT 53KObXtxPzArE3pgUhrqqijnfWg+0pU= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=dZ5s8tEn; spf=pass (imf01.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1794233080; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=jVich8nvMx7lDX/pvruqVV2kTjm69QuzoBabY2+rHJM=; b=S8U5O7Bwb281nOOcdc9nrMUsGWDdHhJcbN4LxpE6fdxySrsqoip5SvtfjOZ6bErz/aj2Ey 7kkST3Bz+W1vmsO4/m63ilfUqH9iirA1VR07t3L6TJGT1Ov3rny/B2vtQ0KbP1BJHneSOF qnn8Ucft5tT+yP+wDUiLRad1Oo5iRDo= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 881AE40C27; Mon, 9 Nov 2026 14:04:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21E7B1F0089F; Mon, 9 Nov 2026 14:04:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794233079; bh=jVich8nvMx7lDX/pvruqVV2kTjm69QuzoBabY2+rHJM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=dZ5s8tEnCgkuCLHe+AvywXX9fW5er432fE+hmxcoFDxYSHquXibvyFXJr0HhTu9mF 4QwK5+xM7VcwmJHm57PdFgBD2B6we8ooMUXjiECMKfp3miAjqB2dGJQ85D0lrF2W73 BVdCrPfmMAhxOj8HZ6D0aZDvDiVX4Vvc7O/VQYV5M51wgVphwJPlc0j3N97zSSXeWh J70K2BmPVXxWZ8W6uCFLEnmTBW8/1QQ86Y1sm08JygPoGON0OUdoifusd7BpxxwrF4 zfR3Upx2a3JvDlQ7m7+DvOseZuSCgYltHiqYyFIT/aQ2/TLqF1/omtYplSjvqnaC3E pL9rVav96wRxg== Message-ID: <763bd31e-789a-4cf5-9e84-d57a375d2d93@kernel.org> Date: Mon, 9 Nov 2026 15:04:33 +0100 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4] mm/memory: use pmdp_get_lockless() for the pmd read in do_fault_around() To: Greg Ungerer , Hui Zhu , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven , Sam Creasey Cc: Hui Zhu , stable+noautosel@kernel.org, linux-m68k@lists.linux-m68k.org References: <20261104091050.117076-1-hui.zhu@linux.dev> <88a6bf17-2189-44a8-8255-50b7ee1d80f2@linux.dev> <6f01317a-1536-4747-ba11-23e27461a694@linux-m68k.org> 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: <6f01317a-1536-4747-ba11-23e27461a694@linux-m68k.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 529FB40016 X-Stat-Signature: mtz3pgsqgnzo1bnfp8ebjexryr1tzugu X-Rspam-User: X-HE-Tag: 1794233080-35619 X-HE-Meta: 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 aNW/lPFE 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 11/9/26 15:02, Greg Ungerer wrote: > Hi Hui, > > On 9/11/26 15:50, Hui Zhu wrote: >> 2026/11/6 20:08, Greg Ungerer: >> >> Hi Greg, >> >>> Hi Hui, >>> >>> The m5475evb_defconfig is supposed to have MMU enabled: >>> >>>       $ ARCH=m68k CROSS_COMPILE=m68k-linux-uclibc- make m5475evb_defconfig >>>         HOSTCC  scripts/basic/fixdep >>>         [snip] >>>         HOSTLD  scripts/kconfig/conf >>>       # >>>       # configuration written to .config >>>       # >>>       $ >>>       $ grep CONFIG_MMU .config >>>       CONFIG_MMU=y >>>       CONFIG_MMU_COLDFIRE=y >>>       CONFIG_MMU_GATHER_NO_RANGE=y >>>       CONFIG_MMU_GATHER_MERGE_VMAS=y >>>       CONFIG_MMU_LAZY_TLB_REFCOUNT=y >>> >>> But something ends up disabling it when you compile. >>> I'll fix this. >>> >>> >>> You should not be able to set MMU=y if configured for the M5208. >>> It doesn't have an MMU. You want the 5475, 5485 or 54418 to test >>> valid MMU=y configurations. >>> >>> Regards >>> Greg >>> >>> >>> >> >> You are right on both counts, and that mail of mine had three things >> wrong. >> >> 1. "No m52xx/m54xx defconfig enables CONFIG_MMU" - wrong.  I grepped the >> defconfig fragments for CONFIG_MMU=y, but MMU is 'default y', so an >> enabled MMU never appears in the fragment.  m5475evb and m54418evb >> both give CONFIG_MMU=y, as you show. >> >> 2. My "m5208evb + CONFIG_MMU=y" test config was not a valid config. >> M520x is 'depends on !MMU', so forcing MMU on leaves the SoC choice >> unsatisfiable and olddefconfig silently drops it: >> >> before:  # CONFIG_MMU is not set / CONFIG_M520x=y >> after:   CONFIG_MMU=y / CONFIG_MMU_COLDFIRE=y / CONFIG_M520x gone >> >> Please disregard the m5208evb row in my codegen numbers. >> >> 3. The "red herring" I flagged was my own doing, not a pre-existing >> problem.  mm/Makefile has 'mmu-$(CONFIG_MMU) := ... memory.o', so a >> NOMMU config never builds mm/memory.o at all; I asked for a target >> that config does not have.  Sorry for the noise on that one. >> >> Retested with the configs you named (7.4-rc1 plus the do_fault_around >> change plus David's cleanup, gcc-m68k-linux-gnu 13.3.0): >> >> m5475evb_defconfig   without David's patch: mm/memory.o fails at >> mcf_pgtable.h:134 with it: full -j24 build ok, vmlinux 4215344 >> bytes, 0 warnings >> >> m54418evb_defconfig  without David's patch: same mcf_pgtable.h:134 >> failure >> >> So the Tested-by I sent covers amiga, sun3 and m5475evb.  It is >> build-tested only - I have no m68k hardware here to boot. > > Thanks for retesting. Looks good. > > >> On MMU being disabled when you compile: I cannot reproduce that. Here >> m5475evb_defconfig gives CONFIG_MMU=y, olddefconfig reports no change, >> two consecutive defconfig runs produce an identical .config, and a full >> build finishes with CONFIG_MMU=y and CONFIG_M547x=y still set and >> .config untouched.  Two differences from your setup that might matter: >> I am on a glibc toolchain rather than uclibc, and building out of tree >> with O= rather than in tree. > > I can't reproduce either now. I must have done something silly when > quickly double checking that config. Multiple configures and builds > and I think it is all doing the right things at configuration and build. > > >> One observation, which may well be unrelated.  m5475evb_defconfig never >> sets CONFIG_M547x - it only ends up with it because the "ColdFire SoC >> type" choice defaults to M520x, which is unavailable under MMU=y, so >> kconfig falls back to the first usable member. m54418evb_defconfig sets >> CONFIG_M5441x=y explicitly.  If that fallback is what breaks on your >> side, making m5475evb explicit would sidestep it. > > FWIW, running "make savedefconfig" on a fully built m5475evb configuration > results in an identical defconfig to arch/m68k/configs/m5475evb_defconfig. > > Anyway, I applied both changes and tested on real hardware. All seems to > work fine. So for ColdFire: > > Tested-by: Greg Ungerer Thanks! -- Cheers, David