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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9D49C4332F for ; Thu, 8 Dec 2022 08:56:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5DF388E0005; Thu, 8 Dec 2022 03:56:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 58F1D8E0001; Thu, 8 Dec 2022 03:56:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 42FAF8E0005; Thu, 8 Dec 2022 03:56:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 3603D8E0001 for ; Thu, 8 Dec 2022 03:56:00 -0500 (EST) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id F094840B4C for ; Thu, 8 Dec 2022 08:55:59 +0000 (UTC) X-FDA: 80218531638.25.6BBE30B Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf23.hostedemail.com (Postfix) with ESMTP id 0425A140004 for ; Thu, 8 Dec 2022 08:55:57 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=S8aaYgIC; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf23.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1670489758; 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=qZzQND0XXn/ac1VVVRiwKzVF2wPIGejtH8QPoB1hHfA=; b=OFV3Y+anFylZXH67Z689TFduod1kBTNzQNWHtdePUamedyU1U9sS7TVDq46/UjhsQmqmds in874/UsETBBYZmZaTPywI9Ve2+acdCkJet/Bo4ZjxlyFMIS4g4LQQhfUI1R3s1aieeY5f 54fyvjf/ZLamaMzD2wjPprXJdHTRtMI= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=S8aaYgIC; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf23.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1670489758; a=rsa-sha256; cv=none; b=Fr5dVmiqforzKlsuGGpEIyhytXgS3I/HCX5jSD+KiyjLNDACFwVg7fAX3J+fjCLJdtbQT0 SRVPUavDt1EoOCPWHyICRwjD/HG8fqnVbwSRihbnnkrFFBODbyEkzMTEn3wnL6WNF5rtRg JR665S5wr7h3/XucHOQzp0Ell7Sdy2E= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670489757; h=from:from: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; bh=qZzQND0XXn/ac1VVVRiwKzVF2wPIGejtH8QPoB1hHfA=; b=S8aaYgIC5VL6s0wQbmR3yEC3ol3KqVKQocps52g4MmXZCT0POwmT0w0x7JA3PXeSSkL+RV SDlKU5YDE1SNwmpdgzuVrKRb/J1/UKJP9kmwJeO5P2QLKJ3VvZKHNcEXpQXbpk0wByf7BF CEnZ1X+DPcTKlNQvspYXxFwbzLtO5Ps= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-5-MUFeaDZDMJWsVcp7V60pIA-1; Thu, 08 Dec 2022 03:55:54 -0500 X-MC-Unique: MUFeaDZDMJWsVcp7V60pIA-1 Received: by mail-wm1-f71.google.com with SMTP id b47-20020a05600c4aaf00b003d031aeb1b6so2102278wmp.9 for ; Thu, 08 Dec 2022 00:55:54 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:organization:references:cc:to :from:content-language:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=qZzQND0XXn/ac1VVVRiwKzVF2wPIGejtH8QPoB1hHfA=; b=EMjmUtROyDsTvnbxcQLGEFd1p0jQA4LGExdrGvYqPAKbjd/cDRV5uxQvCnwQc/1rV7 wMrygAync4MFepDckaCZNOxbIkUizillhEggWVFTUO0aL+xzdTDFJAI/9DLC9/uz8ug9 ifk4z0xBIWZ0fG3HXdN3izA1HZsXnbb3Ez1mwwLxztAAvN4WdrAEhHtpNeaYBouAZo6U YvTOdwvRBzINwx8lO/PliNxPGV34sk8zIGj2cWjptzNoUV+6aXIhae9uftsx4bQ8QiGk kV4p6mscfUUKYOPTdlSc92H19PdMxC+dqh2wIhsUrBjqPR0Q8n/+9M95FQoTOJCwKlos 9asw== X-Gm-Message-State: ANoB5pkpugJ5ljZ7icpdo6+Ew7yLu8aSg1EZQe+7zy75ltmgHotBB/ez sbqlTVyG6Th/p0dnZQLQ4Pv5MYDE2+3JCj756dm2tmsj+/U//gZSquj7m0lbwRL0qnrpfTxo82X pqf8HOQ2MHsc= X-Received: by 2002:a5d:504d:0:b0:242:246c:2f89 with SMTP id h13-20020a5d504d000000b00242246c2f89mr22919574wrt.108.1670489752973; Thu, 08 Dec 2022 00:55:52 -0800 (PST) X-Google-Smtp-Source: AA0mqf668NfxbMXQWSDBD6iCzqqUG4mJSCJROvTfbJs0ERpg3lPeZTVH/8wev7o0MHbpIs1xArxqSg== X-Received: by 2002:a5d:504d:0:b0:242:246c:2f89 with SMTP id h13-20020a5d504d000000b00242246c2f89mr22919565wrt.108.1670489752626; Thu, 08 Dec 2022 00:55:52 -0800 (PST) Received: from ?IPV6:2a09:80c0:192:0:5dac:bf3d:c41:c3e7? ([2a09:80c0:192:0:5dac:bf3d:c41:c3e7]) by smtp.gmail.com with ESMTPSA id o29-20020adfa11d000000b0024278304ef6sm6288982wro.13.2022.12.08.00.55.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 08 Dec 2022 00:55:52 -0800 (PST) Message-ID: Date: Thu, 8 Dec 2022 09:55:49 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH mm-unstable RFC 17/26] powerpc/mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on 32bit book3s From: David Hildenbrand To: Christophe Leroy , "linux-kernel@vger.kernel.org" Cc: Andrew Morton , Hugh Dickins , John Hubbard , Jason Gunthorpe , Mike Rapoport , Yang Shi , Vlastimil Babka , Nadav Amit , Andrea Arcangeli , Peter Xu , "linux-mm@kvack.org" , "x86@kernel.org" , "linux-alpha@vger.kernel.org" , "linux-snps-arc@lists.infradead.org" , "linux-arm-kernel@lists.infradead.org" , "linux-csky@vger.kernel.org" , "linux-hexagon@vger.kernel.org" , "linux-ia64@vger.kernel.org" , "loongarch@lists.linux.dev" , "linux-m68k@lists.linux-m68k.org" , "linux-mips@vger.kernel.org" , "openrisc@lists.librecores.org" , "linux-parisc@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-riscv@lists.infradead.org" , "linux-s390@vger.kernel.org" , "linux-sh@vger.kernel.org" , "sparclinux@vger.kernel.org" , "linux-um@lists.infradead.org" , "linux-xtensa@linux-xtensa.org" , Michael Ellerman , Nicholas Piggin References: <20221206144730.163732-1-david@redhat.com> <20221206144730.163732-18-david@redhat.com> <8be167b6-3836-25c3-9f69-b8b3916ee5b4@csgroup.eu> <0b5b1303-8bcb-c19d-5f63-0e4a3517fea5@redhat.com> Organization: Red Hat In-Reply-To: <0b5b1303-8bcb-c19d-5f63-0e4a3517fea5@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 0425A140004 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: m5oqctgqswwprxsp1x78gpph66n5echb X-HE-Tag: 1670489757-924396 X-HE-Meta: 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 5ZLx5Xyo G19TVOFOEPwE9z4kerPBI/caag5qTcZQ1krUZzFrVC8KL6H0z3k+KVhz4leOgkGg9EkpniESkEVGOjS8gltTV7v2c1cm3eCNsdFVybXtnopBnW+SQhkuhIKwI5+inyDwE/0BtS7orxYkVpzLtURvLle8OJ3zWkVHO9yKJ4ai1Rm+ak7nq+HrK7olJgaxsZlR50k0G0LlfIUQlx+FgvG+j73SBJCfWlOgcLCeGNjHUFoZo3cT+/Ld2lQ/kmRvZd/Rk2QKI5gdKkM2pBfbgraPLaqm5/A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 08.12.22 09:52, David Hildenbrand wrote: > On 07.12.22 14:55, Christophe Leroy wrote: >> >> >> Le 06/12/2022 à 15:47, David Hildenbrand a écrit : >>> We already implemented support for 64bit book3s in commit bff9beaa2e80 >>> ("powerpc/pgtable: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE for book3s") >>> >>> Let's support __HAVE_ARCH_PTE_SWP_EXCLUSIVE also in 32bit by reusing yet >>> unused LSB 2 / MSB 29. There seems to be no real reason why that bit cannot >>> be used, and reusing it avoids having to steal one bit from the swap >>> offset. >>> >>> While at it, mask the type in __swp_entry(). >>> >>> Cc: Michael Ellerman >>> Cc: Nicholas Piggin >>> Cc: Christophe Leroy >>> Signed-off-by: David Hildenbrand >>> --- >>> arch/powerpc/include/asm/book3s/32/pgtable.h | 38 +++++++++++++++++--- >>> 1 file changed, 33 insertions(+), 5 deletions(-) >>> >>> diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h >>> index 75823f39e042..8107835b38c1 100644 >>> --- a/arch/powerpc/include/asm/book3s/32/pgtable.h >>> +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h >>> @@ -42,6 +42,9 @@ >>> #define _PMD_PRESENT_MASK (PAGE_MASK) >>> #define _PMD_BAD (~PAGE_MASK) >>> >>> +/* We borrow the _PAGE_USER bit to store the exclusive marker in swap PTEs. */ >>> +#define _PAGE_SWP_EXCLUSIVE _PAGE_USER >>> + >>> /* And here we include common definitions */ >>> >>> #define _PAGE_KERNEL_RO 0 >>> @@ -363,17 +366,42 @@ static inline void __ptep_set_access_flags(struct vm_area_struct *vma, >>> #define pmd_page(pmd) pfn_to_page(pmd_pfn(pmd)) >>> >>> /* >>> - * Encode and decode a swap entry. >>> - * Note that the bits we use in a PTE for representing a swap entry >>> - * must not include the _PAGE_PRESENT bit or the _PAGE_HASHPTE bit (if used). >>> - * -- paulus >>> + * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that >>> + * are !pte_none() && !pte_present(). >>> + * >>> + * Format of swap PTEs (32bit PTEs): >>> + * >>> + * 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 >>> + * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 >>> + * E H P <- type --> <----------------- offset ------------------> >> >> That's in reversed order. _PAGE_HASHPTE is bit 30 and should be on the >> right hand side. Etc ... > > Ugh, messed it up while converting back and forth between LSB 0 and MSB 0. > > /* > * Format of swap PTEs (32bit PTEs): > * > * 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 > * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 > * <----------------- offset ------------------> <- type --> E H P > > Still wrong, the type is only 5 bits: + * Format of swap PTEs (32bit PTEs): + * + * 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 + * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + * <----------------- offset --------------------> < type -> E H P + * -- Thanks, David / dhildenb