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 A07AEC47DDB for ; Tue, 23 Jan 2024 11:17:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 39F746B0083; Tue, 23 Jan 2024 06:17:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 34F676B0087; Tue, 23 Jan 2024 06:17:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2179F6B0089; Tue, 23 Jan 2024 06:17:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 126986B0083 for ; Tue, 23 Jan 2024 06:17:16 -0500 (EST) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id CF02F120130 for ; Tue, 23 Jan 2024 11:17:15 +0000 (UTC) X-FDA: 81710324430.26.C3AB8B8 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf08.hostedemail.com (Postfix) with ESMTP id 0B205160017 for ; Tue, 23 Jan 2024 11:17:13 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1706008634; 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; bh=XPmj0lEr9+nNOrm4K6uIY/M1FKGGP4UjSn3jiQ9Nc4U=; b=iFbpVCjjKpnEy/UgMBCioAPbkKWwdCAtpmveqMfdmunfNV8XXecFr1ouO2jaGGuTF1rln0 Qw3LsAGRpTN40ur5YMFh9Mz0mUjwJMh7+8u8f2r4DT+4dkkNBGUzjvFuBVzSDDDF06Kfs5 hDRkbTpVTxlOwugTnCA7JKDOnmspCJo= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1706008634; a=rsa-sha256; cv=none; b=XRDJwueFFpl7Dh0hgQ7abZqda0Dv0fjQ4Rg0cnnXDRGprEngFdaJhXlmVSahs5VlqFCS8Q jKY5wdqzTlzUF9Kc9HLnLBiU+NAk41fdOzpB1IQWAKRx9IsnnxcxCQKyJA+3neSGXizB/E ffyrMRS9mdO875TtYDkB39W4uEYqhnI= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5AAB21FB; Tue, 23 Jan 2024 03:17:58 -0800 (PST) Received: from [10.57.77.165] (unknown [10.57.77.165]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 436DD3F762; Tue, 23 Jan 2024 03:17:09 -0800 (PST) Message-ID: <75e99c49-734a-47f4-b7a5-7e346bd2487b@arm.com> Date: Tue, 23 Jan 2024 11:17:07 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 01/11] arm/pgtable: define PFN_PTE_SHIFT on arm and arm64 Content-Language: en-GB To: David Hildenbrand , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Andrew Morton , Matthew Wilcox , Russell King , Catalin Marinas , Will Deacon , Dinh Nguyen , Michael Ellerman , Nicholas Piggin , Christophe Leroy , "Aneesh Kumar K.V" , "Naveen N. Rao" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , "David S. Miller" , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org References: <20240122194200.381241-1-david@redhat.com> <20240122194200.381241-2-david@redhat.com> <46080ac1-7789-499b-b7f3-0231d7bd6de7@redhat.com> <02d42161-a867-424d-bef8-efd67d592cbc@redhat.com> From: Ryan Roberts In-Reply-To: <02d42161-a867-424d-bef8-efd67d592cbc@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 0B205160017 X-Rspam-User: X-Stat-Signature: c4bdedwkwf9qenymnyap5o3e6r68n4cj X-Rspamd-Server: rspam01 X-HE-Tag: 1706008633-97469 X-HE-Meta: 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 25HbN57A 8aSVuGhDoMHFWjokJ6/ar6rILYaP+iG8pAgLt+wqNwa0K2WuUKJBjNbLXIKVBv1hXUGj7lvR7vmnzOe3hL2Uo0ikA0goaQUdVFHAuAtFGwIg2EKVW+RtvJOLif1PGiIigRshZX3nD+4U2rEJ82pW2Bde3b+12SG/k2PYLovJUnTkZw+4H4Dv2tBhGok/TBaMx+s9IpRulPjLPzgoOeZmHjWemWU/4JjcZgyPe 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: List-Subscribe: List-Unsubscribe: On 23/01/2024 11:02, David Hildenbrand wrote: > On 23.01.24 11:48, David Hildenbrand wrote: >> On 23.01.24 11:34, Ryan Roberts wrote: >>> On 22/01/2024 19:41, David Hildenbrand wrote: >>>> We want to make use of pte_next_pfn() outside of set_ptes(). Let's >>>> simpliy define PFN_PTE_SHIFT, required by pte_next_pfn(). >>>> >>>> Signed-off-by: David Hildenbrand >>>> --- >>>>    arch/arm/include/asm/pgtable.h   | 2 ++ >>>>    arch/arm64/include/asm/pgtable.h | 2 ++ >>>>    2 files changed, 4 insertions(+) >>>> >>>> diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h >>>> index d657b84b6bf70..be91e376df79e 100644 >>>> --- a/arch/arm/include/asm/pgtable.h >>>> +++ b/arch/arm/include/asm/pgtable.h >>>> @@ -209,6 +209,8 @@ static inline void __sync_icache_dcache(pte_t pteval) >>>>    extern void __sync_icache_dcache(pte_t pteval); >>>>    #endif >>>>    +#define PFN_PTE_SHIFT        PAGE_SHIFT >>>> + >>>>    void set_ptes(struct mm_struct *mm, unsigned long addr, >>>>                  pte_t *ptep, pte_t pteval, unsigned int nr); >>>>    #define set_ptes set_ptes >>>> diff --git a/arch/arm64/include/asm/pgtable.h >>>> b/arch/arm64/include/asm/pgtable.h >>>> index 79ce70fbb751c..d4b3bd96e3304 100644 >>>> --- a/arch/arm64/include/asm/pgtable.h >>>> +++ b/arch/arm64/include/asm/pgtable.h >>>> @@ -341,6 +341,8 @@ static inline void __sync_cache_and_tags(pte_t pte, >>>> unsigned int nr_pages) >>>>            mte_sync_tags(pte, nr_pages); >>>>    } >>>>    +#define PFN_PTE_SHIFT        PAGE_SHIFT >>> >>> I think this is buggy. And so is the arm64 implementation of set_ptes(). It >>> works fine for 48-bit output address, but for 52-bit OAs, the high bits are not >>> kept contigously, so if you happen to be setting a mapping for which the >>> physical memory block straddles bit 48, this won't work. >> >> Right, as soon as the PTE bits are not contiguous, this stops working, >> just like set_ptes() would, which I used as orientation. >> >>> >>> Today, only the 64K base page config can support 52 bits, and for this, >>> OA[51:48] are stored in PTE[15:12]. But 52 bits for 4K and 16K base pages is >>> coming (hopefully v6.9) and in this case OA[51:50] are stored in PTE[9:8]. >>> Fortunately we already have helpers in arm64 to abstract this. >>> >>> So I think arm64 will want to define its own pte_next_pfn(): >>> >>> #define pte_next_pfn pte_next_pfn >>> static inline pte_t pte_next_pfn(pte_t pte) >>> { >>>     return pfn_pte(pte_pfn(pte) + 1, pte_pgprot(pte)); >>> } >>> > > Digging into the details, on arm64 we have: > > #define pte_pfn(pte)           (__pte_to_phys(pte) >> PAGE_SHIFT) > > and > > #define __pte_to_phys(pte)     (pte_val(pte) & PTE_ADDR_MASK) > > But that implies, that upstream the PFN is always contiguous, no? > But __pte_to_phys() and __phys_to_pte_val() depend on a Kconfig. If PA bits is 52, the bits are not all contiguous: #ifdef CONFIG_ARM64_PA_BITS_52 static inline phys_addr_t __pte_to_phys(pte_t pte) { return (pte_val(pte) & PTE_ADDR_LOW) | ((pte_val(pte) & PTE_ADDR_HIGH) << PTE_ADDR_HIGH_SHIFT); } static inline pteval_t __phys_to_pte_val(phys_addr_t phys) { return (phys | (phys >> PTE_ADDR_HIGH_SHIFT)) & PTE_ADDR_MASK; } #else #define __pte_to_phys(pte) (pte_val(pte) & PTE_ADDR_MASK) #define __phys_to_pte_val(phys) (phys) #endif