From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 427282E62B4 for ; Mon, 16 Mar 2026 14:45:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773672323; cv=none; b=e1oa33W5idggvf5EPge8i7iZ/7vj5J6BtJUihm6VS8Jh9whUh4rDrgvfx0hBd+cr75rdfK2psxN0e+kUmSUEkMNHnzE0TNF9GD9SC3jcnYQWPYPpXMXNk8tNYmd3RyiEODKIDcj4OxTWpy0bzHcPQ7yLyfhsj8KbhmgUzUtsFUs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773672323; c=relaxed/simple; bh=IDgNs3HZYuT9qiw+9So7xncnHaeOkdNOK7hWlAOMll8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=i8KsXN2NhCcwjqSq5Mqg9ME8Z+b389F0GgGpZydNevoKNbSi0Y+/FQ4dzVi5RLkAb6tAKStMj/EY2i+q2n3SY41jH+qyKwDWysSjBwoeMn7MLKP3TWdBK8GXp5Yt2OJgQiDkLbiwXMg1XQLNu9a9q0iD08qSjUBsvsZp6UquVZs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FEsxa7f2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="FEsxa7f2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85B08C19421; Mon, 16 Mar 2026 14:45:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773672323; bh=IDgNs3HZYuT9qiw+9So7xncnHaeOkdNOK7hWlAOMll8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=FEsxa7f28ijZCVDp3G8nrl/AdSeXsXsRscAvW1Ym330MzI/6Hg6hCZfF3F+18c9Mc 8iSmAsk64cePYPYk4hRbOdQOCsYkuXrD2R3oI6Y+wosIoiHpSjeeGVM51vfqln62fz Hd4HIiC32FfOZy7ILN9HRXuAc2Tk41Ao4GUixLFgxp3BmlAsYg7ht91Lw1cnJho1y3 zk3imc8kNB+bZvbUoc3q3NEP6NqQ+tLUrgTsmhSkRIeLunrCfYk5FSq2v0dw1sfu04 cCxZLTgmMy/MIcB7u01MpsSkSTCM0G+hFU3H6k6VvJVHqT4tnfYADeoFIxHB9bpuRQ pjU9LHqWVke/A== Message-ID: <672cdd3d-45ac-4e40-8b4d-6423ace14262@kernel.org> Date: Mon, 16 Mar 2026 15:45:19 +0100 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] arm64: mm: Use generic enum pgtable_level To: Kevin Brodsky , Ryan Roberts , linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon References: <20260316140150.58207-1-kevin.brodsky@arm.com> <415ea4a5-e729-4fe5-b95d-29fcca8f7dbd@arm.com> <132a27ae-4deb-401f-86ad-f8b496bfd778@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 3/16/26 15:38, Kevin Brodsky wrote: > On 16/03/2026 15:22, Ryan Roberts wrote: >>> static phys_addr_t __pgd_pgtable_alloc(struct mm_struct *mm, gfp_t gfp, >>> - enum pgtable_type pgtable_type) >>> + enum pgtable_level pgtable_level) >>> { >>> /* Page is zeroed by init_clear_pgtable() so don't duplicate effort. */ >>> struct ptdesc *ptdesc = pagetable_alloc(gfp & ~__GFP_ZERO, 0); >>> @@ -539,40 +539,42 @@ static phys_addr_t __pgd_pgtable_alloc(struct mm_struct *mm, gfp_t gfp, >>> >>> pa = page_to_phys(ptdesc_page(ptdesc)); >>> >>> - switch (pgtable_type) { >>> - case TABLE_PTE: >>> + switch (pgtable_level) { >>> + case PGTABLE_LEVEL_PTE: >>> BUG_ON(!pagetable_pte_ctor(mm, ptdesc)); >>> break; >>> - case TABLE_PMD: >>> + case PGTABLE_LEVEL_PMD: >>> BUG_ON(!pagetable_pmd_ctor(mm, ptdesc)); >>> break; >>> - case TABLE_PUD: >>> + case PGTABLE_LEVEL_PUD: >>> pagetable_pud_ctor(ptdesc); >>> break; >>> - case TABLE_P4D: >>> + case PGTABLE_LEVEL_P4D: >>> pagetable_p4d_ctor(ptdesc); >>> break; >>> + default: >>> + break; >> nit: I think we should either explicitly support pgd or explicitly bug/warn. Now >> that the enum has PGTABLE_LEVEL_PGD it looks legit to call __pgd_pgtable_alloc() >> to allocate one. But it will currently silently fail to call pagetable_pgd_ctor(). > > I hesitated there as well, eventually I concluded that we're dealing > with kernel page tables so we'll never allocate a PGD anyway... > >> Probably simplest just to call BUG() in the default path? > > ... but that's certainly fine by me :) If we could force it to be inline, we could turn it into a BUILD_BUG(). VM_WARN_ON() might be good enough I guess. -- Cheers, David