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b=FuNxumcjhLbIUa4u7q0QITOPos6Jg58cZS6rJGrWsr8sUeAas/riDW9JQLodaznfl 7n2ltLxLtajU6693I6gVoqJU/MK6syCuIJbFclrsjNsuxY0AXR+nL4YJkj5CrigRDg GOPnAkR8R1dHGkyjOEJf+At0Ld7Wn6d7+JgVHlnBH0Cnd4bixP9TjJmOWj17VZJo6H qcCEfiiRJDCJWw12uhnSl3L146NYIwJ6PALn2wFyyS/VypGipDuB5izoyE7k9cIDjI EXrp6x0pwZu6WvVS3ajxG7L6O0LaK3sfEItjEVT/6Obhm+N3Iz77DfviHAfIF+tPwr i63FsXDy+ZHzA== Message-ID: <04358f9d-3b64-47c0-94dc-f1ef19c22f78@kernel.org> Date: Wed, 9 Sep 2026 17:12:24 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V2 1/2] arm64/mm: Move __check_safe_pte_update() To: Anshuman Khandual , linux-arm-kernel@lists.infradead.org Cc: Mike Rapoport , Andrew Morton , Lorenzo Stoakes , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20260909040005.4148136-1-anshuman.khandual@arm.com> <20260909040005.4148136-2-anshuman.khandual@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: <20260909040005.4148136-2-anshuman.khandual@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: uta19i3hcuyezcstrimgd995ffo1jdw7 X-Rspamd-Queue-Id: DE23B40011 X-Rspamd-Server: rspam07 X-HE-Tag: 1788966749-326989 X-HE-Meta: U2FsdGVkX1+v37dpDz/9T/vyMWtBLW5gUub0kCAjIMIddPtupwP/MlLlK9P/GqGGYvFIXtD5eajSch0x34eAHkLhIyMsOeMyxpFp9tZqzHk5wBlgnkiDyP5t6LEIQeUoesQMPzwVgvuQG5p23ChUtfyOSLuXC465/16xOCtW+nGgpbgnQr04dp7CDweTf5wmSJx5ag1hRNhxA1aU53iTFKN+tl0vehuyvH8kyeAa+CX5Id1q7Y7H3qbFjLMHv8LVmDfWXWdyRpZnGlksar/DS5cWn9GfOo52EHPUacy+sY9iA4j1GAoQAVWgYF7vVL5+QGIvcdqXpc39RrpVAOSfirtgKgWYPjdIqPnh1esIaj8HzBO0Sk/Ah0sYjRPcAOdJgz/byCVbQEUhAihvV8wDXxHoVIq7HexV1opVLiFcL9TlkbeygKzqvdRGZjJfuZGIqqtUYcdMVpobmH9bvEf7E16xuPcVeUYxxDr1KXdPn1Ty9C/3UAJqj06SWg0mXXMRgNoEKkwuJDKKxmJ4G+OWlCgMMkcCJUYdQpZbp+EYWB+4MPa6hXHd2i4mly54Od31r9fa5vzpNP/8O+JxOX/aRDVCPJjiZ6ZTjNLwPbKSHEKHZ9KQt5NKYtlznC6LZ3SmpHpYJaJ2OTp/SFUeu+w6Gjy91Djp4JaB8tYzkp04r6iq/srodz2hb6tAIoaNN7VcBRgMoHejgZ2PqLZ0DEU1uozUsh2dJ+JMNvK00PyBIE/1apmp7g6nmaSbmwH9gSRH2Mr9zQ+QxoCCYeS13bZUvEYTSfTIx5vAW6ldhmybgPm/kjrcZ9CsaArTR27Rzkzpsai06V82vQZCD8vbGddJiqCuDLCaddpjSWXbMerzD5iVZzqfhMbZ1X6Mhcr+A1I2tPPb3VKwcXXi+WGfh3Drw1sIUjIRMRUq2k28ztcyh3vUFNZqGh1gFpYk2tHnckG+OH38jaFm6vVXcmJKS+d FgR/ur4k guYCJgxp1coDWbjvlZJTcBnseCToSeAUHGir1/wrUFFArKDJQ4ZFTirtdWBPAg+sjYkOu/gvyvpxGlielN4IRuW9+l34VYQ/6oRMqYDQLxiE1tauzDLu0RzCoK+wtLhaPoFGzkSXvpGqYgRq70I5BxvJN2YBoTSdFBu/2Grg34/N2HvyQ03UXhoRVT3MRNANRYMNvbGM7ZuKHK4j+0pKNQ2uZE6zIg5/l4jWIWYGuwh4H3oqOGM3mtEgT2A2XDUXn87PXDU591VjjAgMBiv2OMYYftTZDadY6fMHgS25H+X6WXGwbU8SoKZEtn7Acq9a8MV4FukpTuOecPYFiFABe2x9GMd4Y4RWc7FIrDQxUNs/vgm0Y9ZnUhfVCGTaoQe9WvrPPpIwsoRcBesxogSwX9loysACXN/RM8x9Gs7ZoGuLRkVEH+pA7DQ5Qj7xARbXnMm5O Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/9/26 06:00, Anshuman Khandual wrote: > The page table entry print helpers and related macros which are defined in > will not be accessible in platform which > is basically caused by cycling dependency. > > Move __check_safe_pte_update() inside arch/arm64/mm/mmu.c as a preparation > for subsequent usage of the afore mentioned generic MM helpers. While here > drop IS_ENABLED(CONFIG_DEBUG_VM), although wrap __check_safe_pte_update() > inside #ifdef CONFIG_DEBUG_VM that preserves the current code optimization > which is achieved via the static inline functions. > > This does not cause any functional change. > > Cc: Catalin Marinas > Cc: Will Deacon > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual > --- > Changes in V2: > > - Moved __check_safe_pte_update() inside #ifdef CONFIG_DEBUG_VM > - Added empty stub for __check_safe_pte_update() when !CONFIG_DEBUG_VM > - Dropped IS_ENABLED(CONFIG_DEBUG_VM) from __check_safe_pte_update() > > arch/arm64/include/asm/pgtable.h | 49 ++++---------------------------- > arch/arm64/mm/mmu.c | 44 ++++++++++++++++++++++++++++ > 2 files changed, 49 insertions(+), 44 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index e89ec5f4787b..281a512f1fc6 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -387,52 +387,13 @@ static inline pte_t __ptep_get(pte_t *ptep) > extern void __sync_icache_dcache(pte_t pteval); > bool pgattr_change_is_safe(pteval_t old, pteval_t new); > > -/* > - * PTE bits configuration in the presence of hardware Dirty Bit Management > - * (PTE_WRITE == PTE_DBM): > - * > - * Dirty Writable | PTE_RDONLY PTE_WRITE PTE_DIRTY (sw) > - * 0 0 | 1 0 0 > - * 0 1 | 1 1 0 > - * 1 0 | 1 0 1 > - * 1 1 | 0 1 x > - * > - * When hardware DBM is not present, the software PTE_DIRTY bit is updated via > - * the page fault mechanism. Checking the dirty status of a pte becomes: > - * > - * PTE_DIRTY || (PTE_WRITE && !PTE_RDONLY) > - */ > - > -static inline void __check_safe_pte_update(struct mm_struct *mm, pte_t *ptep, > - pte_t pte) > +#ifdef CONFIG_DEBUG_VM > +void __check_safe_pte_update(struct mm_struct *mm, pte_t *ptep, pte_t pte); > +#else > +static inline void __check_safe_pte_update(struct mm_struct *mm, pte_t *ptep, pte_t pte) > { > - pte_t old_pte; > - > - if (!IS_ENABLED(CONFIG_DEBUG_VM)) > - return; > - > - old_pte = __ptep_get(ptep); > - > - if (!pte_valid(old_pte) || !pte_valid(pte)) > - return; > - if (mm != current->active_mm && atomic_read(&mm->mm_users) <= 1) > - return; > - > - /* > - * Check for potential race with hardware updates of the pte > - * (__ptep_set_access_flags safely changes valid ptes without going > - * through an invalid entry). > - */ > - VM_WARN_ONCE(!pte_young(pte), > - "%s: racy access flag clearing: 0x%016llx -> 0x%016llx", > - __func__, pte_val(old_pte), pte_val(pte)); > - VM_WARN_ONCE(pte_write(old_pte) && !pte_dirty(pte), > - "%s: racy dirty state clearing: 0x%016llx -> 0x%016llx", > - __func__, pte_val(old_pte), pte_val(pte)); > - VM_WARN_ONCE(!pgattr_change_is_safe(pte_val(old_pte), pte_val(pte)), > - "%s: unsafe attribute change: 0x%016llx -> 0x%016llx", > - __func__, pte_val(old_pte), pte_val(pte)); > } > +#endif [...] > +#ifdef CONFIG_DEBUG_VM > +void __check_safe_pte_update(struct mm_struct *mm, pte_t *ptep, pte_t pte) > +{ > + pte_t old_pte; > + > + old_pte = __ptep_get(ptep); > + > + if (!pte_valid(old_pte) || !pte_valid(pte)) > + return; > + if (mm != current->active_mm && atomic_read(&mm->mm_users) <= 1) > + return; > + > + /* > + * Check for potential race with hardware updates of the pte > + * (__ptep_set_access_flags safely changes valid ptes without going > + * through an invalid entry). > + */ > + VM_WARN_ONCE(!pte_young(pte), > + "%s: racy access flag clearing: 0x%016llx -> 0x%016llx", > + __func__, pte_val(old_pte), pte_val(pte)); > + VM_WARN_ONCE(pte_write(old_pte) && !pte_dirty(pte), > + "%s: racy dirty state clearing: 0x%016llx -> 0x%016llx", > + __func__, pte_val(old_pte), pte_val(pte)); > + VM_WARN_ONCE(!pgattr_change_is_safe(pte_val(old_pte), pte_val(pte)), > + "%s: unsafe attribute change: 0x%016llx -> 0x%016llx", > + __func__, pte_val(old_pte), pte_val(pte)); > +} > +#endif #endif /* CONFIG_DEBUG_VM */ Might be helpful here. Consider the same in the case above Reviewed-by: David Hildenbrand (Arm) -- Cheers, David