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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFB2AC43219 for ; Mon, 29 Apr 2019 08:12:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A30582087B for ; Mon, 29 Apr 2019 08:12:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727517AbfD2IMw (ORCPT ); Mon, 29 Apr 2019 04:12:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43166 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727439AbfD2IMv (ORCPT ); Mon, 29 Apr 2019 04:12:51 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6262A309265F; Mon, 29 Apr 2019 08:12:51 +0000 (UTC) Received: from localhost (ovpn-12-38.pek2.redhat.com [10.72.12.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 12CA55786; Mon, 29 Apr 2019 08:12:49 +0000 (UTC) Date: Mon, 29 Apr 2019 16:12:46 +0800 From: Baoquan He To: "Kirill A. Shutemov" Cc: linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de, mingo@kernel.org, bp@alien8.de, hpa@zytor.com, kirill.shutemov@linux.intel.com, keescook@chromium.org, peterz@infradead.org, thgarnie@google.com, herbert@gondor.apana.org.au, mike.travis@hpe.com, frank.ramsay@hpe.com, yamada.masahiro@socionext.com Subject: Re: [PATCH v3 RESEND 2/2] x86/mm/KASLR: Fix the size of vmemmap section Message-ID: <20190429081246.GT3584@localhost.localdomain> References: <20190414072804.12560-1-bhe@redhat.com> <20190414072804.12560-3-bhe@redhat.com> <20190422091045.GB3584@localhost.localdomain> <20190428185408.macoxstmy5awsago@kshutemo-mobl1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190428185408.macoxstmy5awsago@kshutemo-mobl1> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Mon, 29 Apr 2019 08:12:51 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/28/19 at 09:54pm, Kirill A. Shutemov wrote: > > @@ -109,6 +110,14 @@ void __init kernel_randomize_memory(void) > > if (memory_tb < kaslr_regions[0].size_tb) > > kaslr_regions[0].size_tb = memory_tb; > > > > + /** > > Nit: that is weird style for inline comment. Right, will fix. Thanks a lot for reviewing. > > > + * Calculate how many TB vmemmap region needs, and aligned to > > + * 1TB boundary. > > + */ > > + vmemmap_size = (kaslr_regions[0].size_tb << (TB_SHIFT - PAGE_SHIFT)) * > > + sizeof(struct page); > > Hm. Don't we need to take into account alignment requirements for struct > page here? I'm worried about some exotic debug kernel config where > sizeof(struct page) doesn't satify __alignof__(struct page). I know sizeof(struct page) has handled its own struct alignment and padding. About __alignof__(struct page), will it conflict with below code to convert pfn < -- > page? Not sure if I got your point. #elif defined(CONFIG_SPARSEMEM_VMEMMAP) /* memmap is virtually contiguous. */ #define __pfn_to_page(pfn) (vmemmap + (pfn)) #define __page_to_pfn(page) (unsigned long)((page) - vmemmap) #elif... > > > + kaslr_regions[2].size_tb = DIV_ROUND_UP(vmemmap_size, 1UL << TB_SHIFT); > > + > > /* Calculate entropy available between regions */ > > remain_entropy = vaddr_end - vaddr_start; > > for (i = 0; i < ARRAY_SIZE(kaslr_regions); i++) > -- > Kirill A. Shutemov