From 66dbe99cfe30e113d2e571e68b9b6a1a8985a157 Mon Sep 17 00:00:00 2001 From: =?utf8?q?M=C3=B4she=20van=20der=20Sterre?= Date: Mon, 1 Feb 2016 22:07:03 +0000 Subject: [PATCH] x86/efi/bgrt: Don't ignore the BGRT if the 'valid' bit is 0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Unintuitively, the BGRT graphic is apparently meant to be usable if the valid bit in not set. The valid bit only conveys uncertainty about the validity in relation to the screen state. Windows 10 actually uses the BGRT image for its boot screen even if not 'valid', for example when the user triggered the boot menu. Because it is unclear if all firmwares will provide a usable graphic in this case, we now look at the BMP magic number as an additional check. Reviewed-by: Josh Triplett Signed-off-by: Môshe van der Sterre Signed-off-by: Matt Fleming Cc: =?UTF-8?q?M=C3=B4she=20van=20der=20Sterre?= Link: http://lkml.kernel.org/r/1454364428-494-10-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar --- arch/x86/platform/efi/efi-bgrt.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c index b0970661870a..a2433817c987 100644 --- a/arch/x86/platform/efi/efi-bgrt.c +++ b/arch/x86/platform/efi/efi-bgrt.c @@ -57,11 +57,6 @@ void __init efi_bgrt_init(void) bgrt_tab->status); return; } - if (bgrt_tab->status != 1) { - pr_debug("Ignoring BGRT: invalid status %u (expected 1)\n", - bgrt_tab->status); - return; - } if (bgrt_tab->image_type != 0) { pr_err("Ignoring BGRT: invalid image type %u (expected 0)\n", bgrt_tab->image_type); @@ -80,6 +75,11 @@ void __init efi_bgrt_init(void) memcpy(&bmp_header, image, sizeof(bmp_header)); memunmap(image); + if (bmp_header.id != 0x4d42) { + pr_err("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n", + bmp_header.id); + return; + } bgrt_image_size = bmp_header.size; bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN); -- 2.34.1