From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752541AbaIMSjU (ORCPT ); Sat, 13 Sep 2014 14:39:20 -0400 Received: from mga14.intel.com ([192.55.52.115]:60268 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752116AbaIMSh5 (ORCPT ); Sat, 13 Sep 2014 14:37:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,518,1406617200"; d="scan'208";a="590897168" From: Ricardo Neri To: Matt Fleming Cc: "H. Peter Anvin" , linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, "Glenn P. Williamson" , Ricardo Neri Subject: [PATCH 5/6] yx86/efi: fixup faults from UEFI firmware Date: Sat, 13 Sep 2014 11:36:15 -0700 Message-Id: <1410633376-8822-6-git-send-email-ricardo.neri-calderon@linux.intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1410633376-8822-1-git-send-email-ricardo.neri-calderon@linux.intel.com> References: <1410633376-8822-1-git-send-email-ricardo.neri-calderon@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Buggy UEFI firmware implementations may try to access the EFI_BOOT_SERVICES_* memory regions even after those regions have been surrendered to the kernel (after calling ExitBootServices() on the firmware). If such regions are not mapped, a page fault will be generated. Fix that up. We are sure that we will not have false positives as those memory regions are reserved and the kernel cannot use them. Signed-off-by: Ricardo Neri --- arch/x86/mm/fault.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index a241946..f084912 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -14,6 +14,7 @@ #include /* hstate_index_to_shift */ #include /* prefetchw */ #include /* exception_enter(), ... */ +#include /* fixup for buggy UEFI firmware*/ #include /* dotraplinkage, ... */ #include /* pgd_*(), ... */ @@ -702,6 +703,13 @@ no_context(struct pt_regs *regs, unsigned long error_code, return; /* + * Try to fixup faults caused by illegal access to BOOT_SERVICES_* + * regions by UEFI firmware. + */ + if (efi_boot_services_fixup(address)) + return; + + /* * Oops. The kernel tried to access some bad page. We'll have to * terminate things with extreme prejudice: */ -- 1.9.1