This is a note to let you know that I've just added the patch titled
ARM: 7840/1: LPAE: don't reject mapping /dev/mem above 4GB
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-7840-1-lpae-don-t-reject-mapping-dev-mem-above-4gb.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3159f372354e8e1f5dee714663d705dd2c7e0759 Mon Sep 17 00:00:00 2001
From: Sergey Dyasly <dserrg@xxxxxxxxx>
Date: Tue, 24 Sep 2013 16:38:00 +0100
Subject: ARM: 7840/1: LPAE: don't reject mapping /dev/mem above 4GB
From: Sergey Dyasly <dserrg@xxxxxxxxx>
commit 3159f372354e8e1f5dee714663d705dd2c7e0759 upstream.
With LPAE enabled, physical address space is larger than 4GB. Allow mapping any
part of it via /dev/mem by using PHYS_MASK to determine valid range.
PHYS_MASK covers 40 bits with LPAE enabled and 32 bits otherwise.
Reported-by: Vassili Karpov <av1474@xxxxxxxx>
Signed-off-by: Sergey Dyasly <dserrg@xxxxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Cc: hujianyang <hujianyang@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/mm/mmap.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -204,13 +204,11 @@ int valid_phys_addr_range(phys_addr_t ad
}
/*
- * We don't use supersection mappings for mmap() on /dev/mem, which
- * means that we can't map the memory area above the 4G barrier into
- * userspace.
+ * Do not allow /dev/mem mappings beyond the supported physical range.
*/
int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
{
- return !(pfn + (size >> PAGE_SHIFT) > 0x00100000);
+ return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT));
}
#ifdef CONFIG_STRICT_DEVMEM
Patches currently in stable-queue which might be from dserrg@xxxxxxxxx are
queue-3.10/arm-7840-1-lpae-don-t-reject-mapping-dev-mem-above-4gb.patch
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