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=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 4871EC282CE for ; Fri, 5 Apr 2019 20:20:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 167792146F for ; Fri, 5 Apr 2019 20:20:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726425AbfDEUUQ (ORCPT ); Fri, 5 Apr 2019 16:20:16 -0400 Received: from terminus.zytor.com ([198.137.202.136]:43519 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725946AbfDEUUQ (ORCPT ); Fri, 5 Apr 2019 16:20:16 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x35KJu3k2896106 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Fri, 5 Apr 2019 13:19:56 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x35KJukF2896103; Fri, 5 Apr 2019 13:19:56 -0700 Date: Fri, 5 Apr 2019 13:19:56 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Baoquan He Message-ID: Cc: bhe@redhat.com, mingo@kernel.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@zytor.com Reply-To: kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org, bhe@redhat.com, mingo@kernel.org, tglx@linutronix.de, hpa@zytor.com In-Reply-To: <20190308025616.21440-3-bhe@redhat.com> References: <20190308025616.21440-3-bhe@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86/mm/KASLR: Reduce randomization granularity for 5-level paging to 1GB Git-Commit-ID: b569c18434987163a05f05a12cdf6a9975c55ff3 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: b569c18434987163a05f05a12cdf6a9975c55ff3 Gitweb: https://git.kernel.org/tip/b569c18434987163a05f05a12cdf6a9975c55ff3 Author: Baoquan He AuthorDate: Fri, 8 Mar 2019 10:56:16 +0800 Committer: Thomas Gleixner CommitDate: Fri, 5 Apr 2019 22:13:52 +0200 x86/mm/KASLR: Reduce randomization granularity for 5-level paging to 1GB The current randomization granularity of 5-level is 512 GB. The mapping of the real mode trampoline has been reduced to one PUD entry, so there is no restriction anymore. Reduce the granularity to 1GB for 5-level paging mode which allows better randomization. [ tglx: Massaged changelog ] Signed-off-by: Baoquan He Signed-off-by: Thomas Gleixner Acked-by: Kirill A. Shutemov Cc: dave.hansen@linux.intel.com Cc: luto@kernel.org Cc: peterz@infradead.org Cc: bp@alien8.de Cc: hpa@zytor.com Cc: keescook@chromium.org Cc: thgarnie@google.com Link: https://lkml.kernel.org/r/20190308025616.21440-3-bhe@redhat.com --- 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 97813751340d..f6ba2791eeb5 100644 --- a/arch/x86/mm/kaslr.c +++ b/arch/x86/mm/kaslr.c @@ -125,10 +125,7 @@ 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; @@ -137,10 +134,7 @@ void __init kernel_randomize_memory(void) * randomization alignment. */ vaddr += get_padding(&kaslr_regions[i]); - 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; } }