From patchwork Mon Jan 29 12:46:35 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13535543 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0C1B3C47422 for ; Mon, 29 Jan 2024 12:47:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=D2P4a/G6l89wYX/N73IlCrwHcBvmMMaZxVszvVOFui8=; b=HB1sFgl8tc6fl2 IRndv1q94ECebmqfpwROQ1S0b/cac8qDvOcoTJZ4Z5gSOmaGGn4zAAe+/6vCAZPvIqYt8DzgG7dDZ rhS36cqxt/7Tu/GK2eNwBancYSXLMXaNANVPYATn/rVc8MrrLHpn71LUUpRCAwvRATHwpnZHUieTo 3sNTm6WgtZqS6oMvLG228y1Ff1m/p5TWiE5sCyjb3yUG794xa7UDnr4cJAEJmSyIb7m0/KWTN3qhk 87nRQBODfMvU8Chh1JTSnC5kOx7iHFn2A4QpNiJtzNlZ7xrlp/da/wu9P8Atc/UlL/ZHYh4as75kH aXrbdiPDUEg0ATx91llQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rUR2i-0000000CeqA-1oIt; Mon, 29 Jan 2024 12:47:16 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rUR2a-0000000Cel8-0JvP for linux-arm-kernel@lists.infradead.org; Mon, 29 Jan 2024 12:47:09 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706532427; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3xazwhF5EUmMqWzaAq7c+f2E0xGFlCS1HyOOY3hDGx8=; b=X9eZ37T6ZptrpLNqE8WpWFciKnIJazgtIcQ6ImCl1h2HUSzHWdTg8xSu8NxrDCWvl+i+i6 FLyGS4FkwjddEEaY0yf3WRXU2WsmszwvwrVICyJFU0lf7UfEnYPbBjzWkmf/UxIgpiyYuO 5YcVAux6aPpdxsKwhaXDIzfExVAbaNQ= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-583-MiBqcbXQPtSpFj1e-vh6bg-1; Mon, 29 Jan 2024 07:47:03 -0500 X-MC-Unique: MiBqcbXQPtSpFj1e-vh6bg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id AFCBF867943; Mon, 29 Jan 2024 12:47:02 +0000 (UTC) Received: from t14s.fritz.box (unknown [10.39.194.46]) by smtp.corp.redhat.com (Postfix) with ESMTP id 118438B; Mon, 29 Jan 2024 12:46:56 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Andrew Morton , Matthew Wilcox , Ryan Roberts , 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 Subject: [PATCH v3 01/15] arm64/mm: Make set_ptes() robust when OAs cross 48-bit boundary Date: Mon, 29 Jan 2024 13:46:35 +0100 Message-ID: <20240129124649.189745-2-david@redhat.com> In-Reply-To: <20240129124649.189745-1-david@redhat.com> References: <20240129124649.189745-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240129_044708_265138_C83382AF X-CRM114-Status: GOOD ( 17.01 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Ryan Roberts Since the high bits [51:48] of an OA are not stored contiguously in the PTE, there is a theoretical bug in set_ptes(), which just adds PAGE_SIZE to the pte to get the pte with the next pfn. This works until the pfn crosses the 48-bit boundary, at which point we overflow into the upper attributes. Of course one could argue (and Matthew Wilcox has :) that we will never see a folio cross this boundary because we only allow naturally aligned power-of-2 allocation, so this would require a half-petabyte folio. So its only a theoretical bug. But its better that the code is robust regardless. I've implemented pte_next_pfn() as part of the fix, which is an opt-in core-mm interface. So that is now available to the core-mm, which will be needed shortly to support forthcoming fork()-batching optimizations. Link: https://lkml.kernel.org/r/20240125173534.1659317-1-ryan.roberts@arm.com Fixes: 4a169d61c2ed ("arm64: implement the new page table range API") Closes: https://lore.kernel.org/linux-mm/fdaeb9a5-d890-499a-92c8-d171df43ad01@arm.com/ Signed-off-by: Ryan Roberts Reviewed-by: Catalin Marinas Reviewed-by: David Hildenbrand Signed-off-by: David Hildenbrand Reviewed-by: Mike Rapoport (IBM) --- arch/arm64/include/asm/pgtable.h | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index b50270107e2f..9428801c1040 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -341,6 +341,22 @@ static inline void __sync_cache_and_tags(pte_t pte, unsigned int nr_pages) mte_sync_tags(pte, nr_pages); } +/* + * Select all bits except the pfn + */ +static inline pgprot_t pte_pgprot(pte_t pte) +{ + unsigned long pfn = pte_pfn(pte); + + return __pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^ pte_val(pte)); +} + +#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)); +} + static inline void set_ptes(struct mm_struct *mm, unsigned long __always_unused addr, pte_t *ptep, pte_t pte, unsigned int nr) @@ -354,7 +370,7 @@ static inline void set_ptes(struct mm_struct *mm, if (--nr == 0) break; ptep++; - pte_val(pte) += PAGE_SIZE; + pte = pte_next_pfn(pte); } } #define set_ptes set_ptes @@ -433,16 +449,6 @@ static inline pte_t pte_swp_clear_exclusive(pte_t pte) return clear_pte_bit(pte, __pgprot(PTE_SWP_EXCLUSIVE)); } -/* - * Select all bits except the pfn - */ -static inline pgprot_t pte_pgprot(pte_t pte) -{ - unsigned long pfn = pte_pfn(pte); - - return __pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^ pte_val(pte)); -} - #ifdef CONFIG_NUMA_BALANCING /* * See the comment in include/linux/pgtable.h