From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F1F8C77B61 for ; Fri, 28 Apr 2023 11:27:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233628AbjD1L1m (ORCPT ); Fri, 28 Apr 2023 07:27:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54198 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229529AbjD1L1j (ORCPT ); Fri, 28 Apr 2023 07:27:39 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9B0CD26BA for ; Fri, 28 Apr 2023 04:27:38 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 72C67C14; Fri, 28 Apr 2023 04:28:22 -0700 (PDT) Received: from FVFF77S0Q05N (unknown [10.57.21.9]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 341A83F64C; Fri, 28 Apr 2023 04:27:37 -0700 (PDT) Date: Fri, 28 Apr 2023 12:27:34 +0100 From: Mark Rutland To: Ard Biesheuvel Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Marc Zyngier , Ryan Roberts , Anshuman Khandual , Kees Cook Subject: Re: [PATCH v3 07/60] arm64: ptdump: Discover start of vmemmap region at runtime Message-ID: References: <20230307140522.2311461-1-ardb@kernel.org> <20230307140522.2311461-8-ardb@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230307140522.2311461-8-ardb@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 07, 2023 at 03:04:29PM +0100, Ard Biesheuvel wrote: > We will soon reclaim the part of the vmemmap region that covers VA space > that is not addressable by the hardware. To avoid confusion, ensure that > the 'vmemmap start' marker points at the start of the region that is > actually being used for the struct page array, rather than the start of > the region we set aside for it at build time. > > Signed-off-by: Ard Biesheuvel > --- > arch/arm64/mm/ptdump.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c > index 910b35f02280cbdb..8f37d6d8b5216473 100644 > --- a/arch/arm64/mm/ptdump.c > +++ b/arch/arm64/mm/ptdump.c > @@ -37,6 +37,7 @@ enum address_markers_idx { > MODULES_END_NR, > VMALLOC_START_NR, > VMALLOC_END_NR, > + VMEMMAP_START_NR, > }; > > static struct addr_marker address_markers[] = { > @@ -386,6 +387,10 @@ static int __init ptdump_init(void) > #endif > address_markers[VMALLOC_END_NR].start_address = VMALLOC_END; > ptdump_initialize(); > + if (vabits_actual < VA_BITS) { > + address_markers[VMEMMAP_START_NR].start_address = > + (unsigned long)virt_to_page(_PAGE_OFFSET(vabits_actual)); > + } As Ryan suggested, I think it'd be worth doing this unconditionally, to keep this simple. Mark. > ptdump_debugfs_register(&kernel_ptdump_info, "kernel_page_tables"); > return 0; > } > -- > 2.39.2 > >