From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f72.google.com (mail-pl0-f72.google.com [209.85.160.72]) by kanga.kvack.org (Postfix) with ESMTP id F21BD6B0003 for ; Tue, 17 Apr 2018 17:16:43 -0400 (EDT) Received: by mail-pl0-f72.google.com with SMTP id g61-v6so13049221plb.10 for ; Tue, 17 Apr 2018 14:16:43 -0700 (PDT) Received: from mga18.intel.com (mga18.intel.com. [134.134.136.126]) by mx.google.com with ESMTPS id o128si12227098pga.653.2018.04.17.14.16.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Apr 2018 14:16:42 -0700 (PDT) Subject: [PATCH 1/2] x86, pti: fix boot problems from Global-bit setting From: Dave Hansen Date: Tue, 17 Apr 2018 14:13:02 -0700 Message-Id: <20180417211302.421F6442@viggo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, Dave Hansen , mceier@gmail.com, aaro.koskinen@nokia.com, aarcange@redhat.com, luto@kernel.org, arjan@linux.intel.com, bp@alien8.de, dan.j.williams@intel.com, dwmw2@infradead.org, gregkh@linuxfoundation.org, hughd@google.com, jpoimboe@redhat.com, jgross@suse.com, keescook@google.com, torvalds@linux-foundation.org, namit@vmware.com, peterz@infradead.org, tglx@linutronix.de These are _very_ lightly tested. I'm throwing them out there for folks are looking for a fix. --- From: Dave Hansen Part of the global bit _setting_ patches also includes clearing the Global bit when we do not want it. That is done with set_memory_nonglobal(), which uses change_page_attr_clear() in pageattr.c under the covers. However, it's pretty clear that change_page_attr_clear() has not been heavily used early in boot, or on kernel text. It has checks like BUG_ON(irqs_disabled()), looking for interrupt disabling but that also trip in early boot on certain preempt configurations. Just copy the existing BUG_ON() sequence to check for early boot. Signed-off-by: Dave Hansen Fixes: 39114b7a7 (x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image) Reported-by: Mariusz Ceier Reported-by: Aaro Koskinen Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Hugh Dickins Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kees Cook Cc: Linus Torvalds Cc: Nadav Amit Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org --- b/arch/x86/mm/pageattr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff -puN arch/x86/mm/pageattr.c~pti-glb-boot-problem-fix arch/x86/mm/pageattr.c --- a/arch/x86/mm/pageattr.c~pti-glb-boot-problem-fix 2018-04-17 14:10:13.553395577 -0700 +++ b/arch/x86/mm/pageattr.c 2018-04-17 14:10:13.559395577 -0700 @@ -172,7 +172,7 @@ static void __cpa_flush_all(void *arg) static void cpa_flush_all(unsigned long cache) { - BUG_ON(irqs_disabled()); + BUG_ON(irqs_disabled() && !early_boot_irqs_disabled); on_each_cpu(__cpa_flush_all, (void *) cache, 1); } @@ -236,7 +236,7 @@ static void cpa_flush_array(unsigned lon unsigned long do_wbinvd = cache && numpages >= 1024; /* 4M threshold */ #endif - BUG_ON(irqs_disabled()); + BUG_ON(irqs_disabled() && !early_boot_irqs_disabled); on_each_cpu(__cpa_flush_all, (void *) do_wbinvd, 1); _