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(p200300cbc741de00bf0fcd46dc1c2de9.dip0.t-ipconnect.de. [2003:cb:c741:de00:bf0f:cd46:dc1c:2de9]) by smtp.gmail.com with ESMTPSA id l6-20020a7bc346000000b0040d81ca11casm40988147wmj.28.2024.01.23.02.48.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 23 Jan 2024 02:48:33 -0800 (PST) Message-ID: <46080ac1-7789-499b-b7f3-0231d7bd6de7@redhat.com> Date: Tue, 23 Jan 2024 11:48:31 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 01/11] arm/pgtable: define PFN_PTE_SHIFT on arm and arm64 To: Ryan Roberts , 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> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: 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: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 5E958140022 X-Stat-Signature: qrr91wkrgpsgn6s5zmqwx7jymdugz7zw X-Rspam-User: X-HE-Tag: 1706006917-140870 X-HE-Meta: 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 LRkt3mTQ 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 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 23.01.24 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)); > } > > I'll do a separate patch to fix the already broken arm64 set_ptes() implementation. Make sense. > > I'm not sure if this type of problem might also apply to other arches? I saw similar handling in the PPC implementation of set_ptes, but was not able to convince me that it is actually required there. pte_pfn on ppc does: static inline unsigned long pte_pfn(pte_t pte) { return (pte_val(pte) & PTE_RPN_MASK) >> PTE_RPN_SHIFT; } But that means that the PFNs *are* contiguous. If high bits are used for something else, then we might produce a garbage PTE on overflow, but that shouldn't really matter I concluded for folio_pte_batch() purposes, we'd not detect "belongs to this folio batch" either way. Maybe it's likely cleaner to also have a custom pte_next_pfn() on ppc, I just hope that we don't lose any other arbitrary PTE bits by doing the pte_pgprot(). I guess pte_pfn() implementations should tell us if anything special needs to happen. -- Cheers, David / dhildenb