From patchwork Fri Feb 3 16:36:16 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joseph Salisbury X-Patchwork-Id: 723818 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3vFMvK6xxcz9s7H; Sat, 4 Feb 2017 03:36:29 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1cZgqZ-00028d-Ck; Fri, 03 Feb 2017 16:36:27 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1cZgqP-00027H-Vm for kernel-team@lists.ubuntu.com; Fri, 03 Feb 2017 16:36:17 +0000 Received: from 1.general.jsalisbury.us.vpn ([10.172.67.212] helo=vp9) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1cZgqP-0000n9-KQ for kernel-team@lists.ubuntu.com; Fri, 03 Feb 2017 16:36:17 +0000 Received: by vp9 (Postfix, from userid 1000) id A335F6004C; Fri, 3 Feb 2017 11:36:16 -0500 (EST) From: Joseph Salisbury To: kernel-team@lists.ubuntu.com Subject: [SRU][Yakkety][Zesty][PATCH 1/1] UBUNTU: SAUCE: x86/efi: Always map first physical page into EFI pagetables Date: Fri, 3 Feb 2017 11:36:16 -0500 Message-Id: <707a460b19f6dec6b756494ce8e1a251a799a27a.1486138809.git.joseph.salisbury@canonical.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: References: In-Reply-To: References: X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com From: Jiri Kosina BugLink: http://bugs.launchpad.net/bugs/1659340 Commit 129766708 ("x86/efi: Only map RAM into EFI page tables if in mixed-mode") stopped creating 1:1 mapping for all RAM in case of running in native 64bit mode. It turns out though that there are 64bit EFI implementations in the wild (this particular problem has been reported on Lenovo Yoga 710-11IKB) which still make use of first physical page for their own private use even though they explicitly mark it EFI_CONVENTIONAL_MEMORY in the memory map. In case there is no mapping for this particular frame in EFI pagetables, as soon as firmware tries to make use of it, triple fault occurs and the system reboots (in case of Yoga 710-11IKB this is very early during boot). Fix that by always mapping the first page of physical memory into EFI pagetables. We're on a safe side, as trim_bios_range() will reserve the first page and isolate it away from memory allocators anyway. Note: just reverting 129766708 is not enough on v4.9-rc1+ to fix the regression on affected hardware, as commit ab72a27da ("x86/efi: Consolidate region mapping logic") later made the first physical frame not to be mapped anyway. Reported-by: Hanka Pavlikova Signed-off-by: Jiri Kosina Cc: stable@kernel.org # v4.8+ Cc: Waiman Long Cc: Borislav Petkov Cc: Laura Abbott Cc: Vojtech Pavlik Cc: Borislav Petkov Cc: Ard Biesheuvel Fixes: 129766708 ("x86/efi: Only map RAM into EFI page tables if in mixed-mode") Signed-off-by: Matt Fleming Signed-off-by: Joseph Salisbury --- arch/x86/platform/efi/efi_64.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 8dd3784..5be3868 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -240,6 +240,22 @@ int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages) efi_scratch.use_pgd = true; /* + * Certain firmware versions are way too sentimential and still believe + * they are exclusive and unquestionable owners of first physical page + * even though they explicitly mark it as EFI_CONVENTIONAL_MEMORY + * (but then write-access it later during SetVirtualAddressMap()). + * + * Create 1:1 mapping for this page to avoid triple faults during early + * boot with such firmware. We're on a safe side, as trim_bios_range() + * will reserve the first page and isolate it away from memory + * allocators anyway. + */ + if (kernel_map_pages_in_pgd(pgd, 0x0, 0x0, 1, _PAGE_RW)) { + pr_err("Failed to create 1:1 mapping of first page\n"); + return 1; + } + + /* * When making calls to the firmware everything needs to be 1:1 * mapped and addressable with 32-bit pointers. Map the kernel * text and allocate a new stack because we can't rely on the