| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 07/48] ARM: 7840/1: LPAE: dont reject mapping /dev/mem above 4GB | Date | Sun, 11 May 2014 21:19:41 +0200 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Sergey Dyasly <dserrg@gmail.com>
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>
--- 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
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