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authorSergey Dyasly <dserrg@gmail.com>2013-09-24 16:38:00 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-13 13:59:41 +0200
commitb6b461e90f8fbebb8fa46f363999ed5023be7d3c (patch)
treef1c57d2f39278100b4329d249c37877d3d55c965
parentd306606e58d53a9d8cd78fefacbe9a50b3aa9fcd (diff)
downloadlinux-linaro-stable-b6b461e90f8fbebb8fa46f363999ed5023be7d3c.tar.gz
ARM: 7840/1: LPAE: don't reject mapping /dev/mem above 4GB
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@comtv.ru> Signed-off-by: Sergey Dyasly <dserrg@gmail.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Cc: hujianyang <hujianyang@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm/mm/mmap.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index f0ef2f7d4ad7..5ef506c6f492 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -204,13 +204,11 @@ int valid_phys_addr_range(phys_addr_t addr, size_t size)
}
/*
- * 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