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 2102DC77B7C for ; Mon, 17 Apr 2023 15:48:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231435AbjDQPsN (ORCPT ); Mon, 17 Apr 2023 11:48:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231420AbjDQPsJ (ORCPT ); Mon, 17 Apr 2023 11:48:09 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2B278A24F for ; Mon, 17 Apr 2023 08:48:05 -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 62B701691; Mon, 17 Apr 2023 08:48:48 -0700 (PDT) Received: from [10.57.68.227] (unknown [10.57.68.227]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 742CB3F5A1; Mon, 17 Apr 2023 08:48:03 -0700 (PDT) Message-ID: Date: Mon, 17 Apr 2023 16:48:02 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.1 Subject: Re: [PATCH v3 32/60] arm64: head: allocate more pages for the kernel mapping Content-Language: en-US To: Ard Biesheuvel , linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Marc Zyngier , Mark Rutland , Anshuman Khandual , Kees Cook References: <20230307140522.2311461-1-ardb@kernel.org> <20230307140522.2311461-33-ardb@kernel.org> From: Ryan Roberts In-Reply-To: <20230307140522.2311461-33-ardb@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/03/2023 14:04, Ard Biesheuvel wrote: > In preparation for switching to an early kernel mapping routine that > maps each segment according to its precise boundaries, and with the > correct attributes, let's allocate some extra pages for page tables for > the 4k page size configuration. This is necessary because the start and > end of each segment may not be aligned to the block size, and so we'll > need an extra page table at each segment boundary. > > Signed-off-by: Ard Biesheuvel > --- > arch/arm64/include/asm/kernel-pgtable.h | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h > index 4d13c73171e1e360..50b5c145358a5d8e 100644 > --- a/arch/arm64/include/asm/kernel-pgtable.h > +++ b/arch/arm64/include/asm/kernel-pgtable.h > @@ -80,7 +80,7 @@ > + EARLY_PGDS((vstart), (vend), add) /* each PGDIR needs a next level page table */ \ > + EARLY_PUDS((vstart), (vend), add) /* each PUD needs a next level page table */ \ > + EARLY_PMDS((vstart), (vend), add)) /* each PMD needs a next level page table */ > -#define INIT_DIR_SIZE (PAGE_SIZE * EARLY_PAGES(KIMAGE_VADDR, _end, EARLY_KASLR)) > +#define INIT_DIR_SIZE (PAGE_SIZE * (EARLY_PAGES(KIMAGE_VADDR, _end, EARLY_KASLR) + EARLY_SEGMENT_EXTRA_PAGES)) > > /* the initial ID map may need two extra pages if it needs to be extended */ > #if VA_BITS < 48 > @@ -101,6 +101,15 @@ > #define SWAPPER_TABLE_SHIFT PMD_SHIFT > #endif > > +/* The number of segments in the kernel image (text, rodata, inittext, initdata, data+bss) */ > +#define KERNEL_SEGMENT_COUNT 5 > + > +#if SWAPPER_BLOCK_SIZE > SEGMENT_ALIGN > +#define EARLY_SEGMENT_EXTRA_PAGES (KERNEL_SEGMENT_COUNT + 1) I'm guessing the block size for 4K pages is PMD, so you need these extra pages to define PTEs for the case where the section start/end addresses are not on exact 2MB boundaries? But in that case, isn't it possible that you would need 2 extra PTE tables per segment - one for the start and one for the end? > +#else > +#define EARLY_SEGMENT_EXTRA_PAGES 0 > +#endif > + > /* > * Initial memory map attributes. > */