From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:17378 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753409AbcESEV5 (ORCPT ); Thu, 19 May 2016 00:21:57 -0400 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: Wang YanQing , Matt Fleming , Ard Biesheuvel , David Herrmann , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Tomi Valkeinen , linux-efi@vger.kernel.org, Ingo Molnar , Sasha Levin Subject: [added to the 4.1 stable tree] x86/sysfb_efi: Fix valid BAR address range check Date: Thu, 19 May 2016 00:19:42 -0400 Message-Id: <1463631606-32540-43-git-send-email-sasha.levin@oracle.com> In-Reply-To: <1463631606-32540-1-git-send-email-sasha.levin@oracle.com> References: <1463631606-32540-1-git-send-email-sasha.levin@oracle.com> Sender: stable-owner@vger.kernel.org List-ID: From: Wang YanQing This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =============== [ Upstream commit c10fcb14c7afd6688c7b197a814358fecf244222 ] The code for checking whether a BAR address range is valid will break out of the loop when a start address of 0x0 is encountered. This behaviour is wrong since by breaking out of the loop we may miss the BAR that describes the EFI frame buffer in a later iteration. Because of this bug I can't use video=efifb: boot parameter to get efifb on my new ThinkPad E550 for my old linux system hard disk with 3.10 kernel. In 3.10, efifb is the only choice due to DRM/I915 not supporting the GPU. This patch also add a trivial optimization to break out after we find the frame buffer address range without testing later BARs. Signed-off-by: Wang YanQing [ Rewrote changelog. ] Signed-off-by: Matt Fleming Reviewed-by: Peter Jones Cc: Cc: Ard Biesheuvel Cc: David Herrmann Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tomi Valkeinen Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1462454061-21561-2-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- arch/x86/kernel/sysfb_efi.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/sysfb_efi.c b/arch/x86/kernel/sysfb_efi.c index b285d4e..5da924b 100644 --- a/arch/x86/kernel/sysfb_efi.c +++ b/arch/x86/kernel/sysfb_efi.c @@ -106,14 +106,24 @@ static int __init efifb_set_system(const struct dmi_system_id *id) continue; for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) { resource_size_t start, end; + unsigned long flags; + + flags = pci_resource_flags(dev, i); + if (!(flags & IORESOURCE_MEM)) + continue; + + if (flags & IORESOURCE_UNSET) + continue; + + if (pci_resource_len(dev, i) == 0) + continue; start = pci_resource_start(dev, i); - if (start == 0) - break; end = pci_resource_end(dev, i); if (screen_info.lfb_base >= start && screen_info.lfb_base < end) { found_bar = 1; + break; } } } -- 2.5.0