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Date: Thu, 5 May 2016 07:03:35 -0700
From: tip-bot for Wang YanQing <tipbot@...or.com>
To: linux-tip-commits@...r.kernel.org
Cc: udknight@...il.com, pjones@...hat.com, hpa@...or.com,
tglx@...utronix.de, matt@...eblueprint.co.uk, peterz@...radead.org,
mingo@...nel.org, dh.herrmann@...il.com, stable@...r.kernel.org,
tomi.valkeinen@...com, linux-kernel@...r.kernel.org,
ard.biesheuvel@...aro.org, torvalds@...ux-foundation.org
Subject: [tip:efi/urgent] x86/sysfb_efi: Fix valid BAR address range check
Commit-ID: c10fcb14c7afd6688c7b197a814358fecf244222
Gitweb: http://git.kernel.org/tip/c10fcb14c7afd6688c7b197a814358fecf244222
Author: Wang YanQing <udknight@...il.com>
AuthorDate: Thu, 5 May 2016 14:14:21 +0100
Committer: Ingo Molnar <mingo@...nel.org>
CommitDate: Thu, 5 May 2016 16:01:00 +0200
x86/sysfb_efi: Fix valid BAR address range check
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 <udknight@...il.com>
[ Rewrote changelog. ]
Signed-off-by: Matt Fleming <matt@...eblueprint.co.uk>
Reviewed-by: Peter Jones <pjones@...hat.com>
Cc: <stable@...r.kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: David Herrmann <dh.herrmann@...il.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@...com>
Cc: linux-efi@...r.kernel.org
Link: http://lkml.kernel.org/r/1462454061-21561-2-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
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;
}
}
}
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