From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 06E644534A9; Thu, 1 Oct 2026 11:19:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790853588; cv=none; b=ghoV/XNSmMIOUo/FSNNFZm+VxF6w5XRvEVbgH9LqQ5GGTrmSxzSGfnUHtPR9MLZt44lQ99E3Ww3JM8s1GXlUcc9akwACr0p/g2Ai+n0EWF89sbq/RtJgu6zavuBUXnXONMWx4S9R6wPkGxzNi2H2fWBDYER0cQjs3eoZipyiqxM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790853588; c=relaxed/simple; bh=fSbYKr93qa7jzlMGeaLdw5Bn3RmMMNsLFooEHa/fpOo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ky9P0y0AalwRUcyOEvY8yu4rx/VhQNUlUmGTcCOV0KbnRjE2kUfU/zRDwzsI/xEF2TkGr1bUxEZLF7dk+zHOzdGJqUxfBmF8Ot5XJm2AYHS7X5ExM+hcPrwkYbnofNihvosO8Y0F3vFp8UoauB0Ur6GH4I0Atik0WvQD5s68IWw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nMbvvVKz; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nMbvvVKz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E3D31F000FF; Thu, 1 Oct 2026 11:19:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790853586; bh=QFQFkWDnC7jLqttKnpyOh/RzATFY2MNc7SamlM3r9CY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=nMbvvVKzbLfiBDmwx5000bOF+s2wwI5IUpFYTI/iQmTRFaqEIRPkxAnIgPgtRkbJ0 aqsar7aBQQWF17j7qm7re98QK2MXp/SjTXPj6Jaave3l2lYP+m0Pz8NwLOPWtJii3d +/JslHjvapBJl1QgKIGa/tDOAtKuTUTa7pAFOFLGVfS4bA6CsFZeBwjmyDK95aJdS1 9ukUJ793Yc9KrIfWLnhz27LyPhzI15LRk/k7ivImSysTbIiVyAS0KMu7lJbra/Pesz pWFxc9zKJFzMFMEYqdxKzyhJGBS5wy0U/BzhIpkvR+1jEWvnD3SfLtCnn4oQTcUb0z 8MuItJ69xgTaw== Message-ID: Date: Thu, 1 Oct 2026 13:17:18 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 5/9] mm: convert PTE table entry to pte To: Muhammad Usama Anjum , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Xu Xin , Chengming Zhou , Jann Horn , Muchun Song , Oscar Salvador , Pedro Falcato , Arnd Bergmann , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Peter Zijlstra , Pasha Tatashin , Rik van Riel , Harry Yoo , Lance Yang , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , Uladzislau Rezki , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Ian Rogers , Adrian Hunter , James Clark , SJ Park , "Matthew Wilcox (Oracle)" , Jan Kara , Jason Gunthorpe , John Hubbard , Peter Xu , Leon Romanovsky , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Miaohe Lin , Naoya Horiguchi , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Dennis Zhou , Tejun Heo , Christoph Lameter , Johannes Weiner , Qi Zheng , Shakeel Butt , Axel Rasmussen , Yuanchu Xie , Wei Xu , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , David Airlie , Simona Vetter , Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, damon@lists.linux.dev, kasan-dev@googlegroups.com, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, xen-devel@lists.xenproject.org References: <20260922-pte0-v3-0-5670b8cb9059@arm.com> <20260922-pte0-v3-5-5670b8cb9059@arm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/22/26 19:12, Muhammad Usama Anjum wrote: > The non-MMU stub receives hw_pte_t but returns a software PTE value. It > has no attached PTE that requires ptep_get(), so convert only the stored > entry through __pte_from_hw(). > > Signed-off-by: Muhammad Usama Anjum > --- > Changes since v1: > - Explain why the NOMMU stub does not use ptep_get(). > - Use software PTE value terminology. > --- > include/linux/hugetlb.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index 0d2101facaa50..637fc863d3687 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -1278,7 +1278,8 @@ static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, > #ifdef CONFIG_MMU > return ptep_get(ptep); > #else > - return *ptep; > + /* No attached PTE that requires ptep_get(). */ > + return __pte_from_hw(*ptep); > #endif > } > > Okay, that looks quite odd. No NOMMU code should ever be calling this helper. I can understand that some NOMMU code might, for some odd reason, end up including hguetlb.h where we have !CONFIG_HUGETLB_PAGE. But let's see who actually calls huge_ptep_clear_flush(): arch/arm64/mm/hugetlbpage.c: only with CONFIG_HUGETLB_PAGE mm/hugetlb.c: only with CONFIG_HUGETLB_PAGE mm/rmap.c: only after checking folio_test_hugetlb(). I suspect we can simply do: diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 80a5a03e9cee..8642c863c1b7 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -1268,15 +1268,8 @@ static inline void hugetlb_count_sub(long l, struct mm_struct *mm) pte_t huge_ptep_get(struct mm_struct *mm, unsigned long addr, pte_t *ptep); unsigned long huge_pte_dirty(pte_t pte); -static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep) -{ -#ifdef CONFIG_MMU - return ptep_get(ptep); -#else - return *ptep; -#endif -} +pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, unsigned long addr, + pte_t *ptep); static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte, unsigned long sz) -- Cheers, David