From: dserrg@gmail.com (Sergey Dyasly) Date: Tue, 2 Jul 2013 19:58:05 +0400 Subject: [PATCH v2] ARM: LPAE: don't reject mapping /dev/mem above 4GB Message-ID: <1372780685-2528-1-git-send-email-dserrg@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. PHYS_MASK covers 40 bits with LPAE enabled and 32 bits otherwise. Signed-off-by: Sergey Dyasly --- v2: - Removed #ifdef and changed original function as suggested by Catalin Marinas arch/arm/mm/mmap.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index 10062ce..09bab92 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 << PAGE_SHIFT) + size) & ~PHYS_MASK); } #ifdef CONFIG_STRICT_DEVMEM -- 1.8.1.2