[PATCH] ARM: LPAE: don't reject mapping /dev/mem above 4GB
From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2013-06-28 09:00:02
On Thu, Jun 27, 2013 at 06:24:35PM +0100, Sergey Dyasly wrote:
quoted hunk ↗ jump to hunk
With LPAE enabled, physical address space is larger than 4GB. Allow mapping any part of it via /dev/mem by utilizing the same check as in arm64. Reported-by: Vassili Karpov <redacted> Tested-by: Vassili Karpov <redacted> Signed-off-by: Sergey Dyasly <redacted> --- arch/arm/mm/mmap.c | 10 ++++++++++ 1 file changed, 10 insertions(+)diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 10062ce..8f1bbbc 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c@@ -203,6 +203,15 @@ int valid_phys_addr_range(phys_addr_t addr, size_t size) return 1; } +#ifdef CONFIG_ARM_LPAE +/* + * 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 << PAGE_SHIFT) + size) & ~PHYS_MASK); +} +#else /* * 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@@ -212,6 +221,7 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) { return !(pfn + (size >> PAGE_SHIFT) > 0x00100000);
BTW, I think you can use the original function with something like this: return !(pfn + (size >> PAGE_SHIFT) > (1 << (PHYS_MASK_SHIFT - PAGE_SHIFT))); and define PHYS_MASK_SHIFT to 32 for classic MMU. -- Catalin