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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 4C918C43381 for ; Sun, 24 Feb 2019 13:22:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2410B206B6 for ; Sun, 24 Feb 2019 13:22:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728396AbfBXNWu (ORCPT ); Sun, 24 Feb 2019 08:22:50 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45790 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728374AbfBXNWu (ORCPT ); Sun, 24 Feb 2019 08:22:50 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 00A8A30821A0; Sun, 24 Feb 2019 13:22:50 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-25.pek2.redhat.com [10.72.12.25]) by smtp.corp.redhat.com (Postfix) with ESMTP id C64536017E; Sun, 24 Feb 2019 13:22:43 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, kirill.shutemov@linux.intel.com, keescook@chromium.org, thgarnie@google.com, Baoquan He Subject: [PATCH 2/2] x86/mm/KASLR: Change the granularity of randomization to PUD size in 5-level Date: Sun, 24 Feb 2019 21:22:31 +0800 Message-Id: <20190224132231.4878-3-bhe@redhat.com> In-Reply-To: <20190224132231.4878-1-bhe@redhat.com> References: <20190224132231.4878-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Sun, 24 Feb 2019 13:22:50 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current randomization granularity of 5-level is 512 GB. Improve it to 1 GB. This can add more randomness to memory region KASLR in 5-level paging mode Signed-off-by: Baoquan He --- arch/x86/mm/kaslr.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c index 6b2a06c36b6f..248509986f1f 100644 --- a/arch/x86/mm/kaslr.c +++ b/arch/x86/mm/kaslr.c @@ -204,10 +204,7 @@ void __init kernel_randomize_memory(void) */ entropy = remain_entropy / (ARRAY_SIZE(kaslr_regions) - i); prandom_bytes_state(&rand_state, &rand, sizeof(rand)); - if (pgtable_l5_enabled()) - entropy = (rand % (entropy + 1)) & P4D_MASK; - else - entropy = (rand % (entropy + 1)) & PUD_MASK; + entropy = (rand % (entropy + 1)) & PUD_MASK; vaddr += entropy; *kaslr_regions[i].base = vaddr; @@ -216,10 +213,7 @@ void __init kernel_randomize_memory(void) * randomization alignment. */ vaddr += kaslr_regions[i].size_tb << TB_SHIFT; - if (pgtable_l5_enabled()) - vaddr = round_up(vaddr + 1, P4D_SIZE); - else - vaddr = round_up(vaddr + 1, PUD_SIZE); + vaddr = round_up(vaddr + 1, PUD_SIZE); remain_entropy -= entropy; } } -- 2.17.2