Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933060AbcKOMDQ (ORCPT ); Tue, 15 Nov 2016 07:03:16 -0500 Received: from mail-wm0-f67.google.com ([74.125.82.67]:36432 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932211AbcKOMC6 (ORCPT ); Tue, 15 Nov 2016 07:02:58 -0500 From: David Herrmann To: linux-kernel@vger.kernel.org Cc: Matt Fleming , Ingo Molnar , x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Tom Gundersen , David Herrmann Subject: [PATCH 2/2] x86/sysfb: fix lfb_size calculation Date: Tue, 15 Nov 2016 13:01:58 +0100 Message-Id: <20161115120158.15388-3-dh.herrmann@gmail.com> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161115120158.15388-1-dh.herrmann@gmail.com> References: <20161115120158.15388-1-dh.herrmann@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2341 Lines: 66 The screen_info.lfb_size field is shifted by 16 bits *only* in case of VBE. This has historical reasons since VBE advertised it similarly. However, in case of EFI framebuffers, the size is no longer shifted. Fix the x86 simple-framebuffer setup code to use the correct size in the non-VBE case. While at it, avoid variable abbreviations and rename 'len' to 'length', and use the correct types matching the screen_info definition. Signed-off-by: David Herrmann --- arch/x86/kernel/sysfb_simplefb.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/sysfb_simplefb.c b/arch/x86/kernel/sysfb_simplefb.c index 35b8641..85195d4 100644 --- a/arch/x86/kernel/sysfb_simplefb.c +++ b/arch/x86/kernel/sysfb_simplefb.c @@ -66,8 +66,8 @@ __init int create_simplefb(const struct screen_info *si, { struct platform_device *pd; struct resource res; - unsigned long len; - u64 base; + u64 base, size; + u32 length; /* * If the 64BIT_BASE capability is set, ext_lfb_base will contain the @@ -82,11 +82,20 @@ __init int create_simplefb(const struct screen_info *si, return -EINVAL; } - /* don't use lfb_size as it may contain the whole VMEM instead of only - * the part that is occupied by the framebuffer */ - len = mode->height * mode->stride; - len = PAGE_ALIGN(len); - if (len > (u64)si->lfb_size << 16) { + /* + * Don't use lfb_size as IORESOURCE size, since it may contain the + * entire VMEM, and thus require huge mappings. Use just the part we + * need, that is, the part where the framebuffer is located. But verify + * that it does not exceed the advertised VMEM. + * Note that in case of VBE, the lfb_size is shifted by 16 bits for + * historical reasons. + */ + size = si->lfb_size; + if (si->orig_video_isVGA == VIDEO_TYPE_VLFB) + size <<= 16; + length = mode->height * mode->stride; + length = PAGE_ALIGN(length); + if (length > size) { printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n"); return -EINVAL; } @@ -96,7 +105,7 @@ __init int create_simplefb(const struct screen_info *si, res.flags = IORESOURCE_MEM | IORESOURCE_BUSY; res.name = simplefb_resname; res.start = base; - res.end = res.start + len - 1; + res.end = res.start + length - 1; if (res.end <= res.start) return -EINVAL; -- 2.10.2