From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Wang YanQing <udknight@gmail.com>,
Matt Fleming <matt@codeblueprint.co.uk>,
Peter Jones <pjones@redhat.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
David Herrmann <dh.herrmann@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Tomi Valkeinen <tomi.valkeinen@ti.com>,
linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>
Subject: [PATCH 4.5 65/88] x86/sysfb_efi: Fix valid BAR address range check
Date: Mon, 9 May 2016 09:21:54 +0200 [thread overview]
Message-ID: <20160509071955.373943811@linuxfoundation.org> (raw)
In-Reply-To: <20160509071952.129092535@linuxfoundation.org>
4.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Wang YanQing <udknight@gmail.com>
commit c10fcb14c7afd6688c7b197a814358fecf244222 upstream.
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@gmail.com>
[ Rewrote changelog. ]
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Peter Jones <pjones@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
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 <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/sysfb_efi.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--- 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
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;
}
}
}
prev parent reply other threads:[~2016-05-09 7:21 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20160509071952.129092535@linuxfoundation.org>
[not found] ` <20160509071952.129092535-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
2016-05-09 7:21 ` [PATCH 4.5 59/88] MAINTAINERS: Remove asterisk from EFI directory names Greg Kroah-Hartman
2016-05-09 7:21 ` Greg Kroah-Hartman [this message]
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