From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Wed, 11 Dec 2013 10:44:29 +0000 Subject: [PATCH] arm64: Correct virt_addr_valid In-Reply-To: <1386724982-16997-2-git-send-email-lauraa@codeaurora.org> References: <1386724982-16997-1-git-send-email-lauraa@codeaurora.org> <1386724982-16997-2-git-send-email-lauraa@codeaurora.org> Message-ID: <20131211104429.GE26730@mudshark.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Dec 11, 2013 at 01:23:02AM +0000, Laura Abbott wrote: > The definition of virt_addr_valid is that virt_addr_valid should > return true if and only if virt_to_page returns a valid pointer. > The current definition of virt_addr_valid only checks against the > virtual address range. There's no guarantee that just because a > virtual address falls bewteen PAGE_OFFSET and high_memory the > associated physical memory has a valid backing struct page. Follow > the example of other architectures and convert to pfn_valid to > verify that the virtual address is actually valid. > > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Nicolas Pitre > Signed-off-by: Laura Abbott > --- > arch/arm64/include/asm/memory.h | 3 +-- > 1 files changed, 1 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 3776217..9dc5dc3 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -146,8 +146,7 @@ static inline void *phys_to_virt(phys_addr_t x) > #define ARCH_PFN_OFFSET PHYS_PFN_OFFSET > > #define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT) > -#define virt_addr_valid(kaddr) (((void *)(kaddr) >= (void *)PAGE_OFFSET) && \ > - ((void *)(kaddr) < (void *)high_memory)) > +#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT) Hmm, this is pretty expensive on both arm and arm64, since we end up doing a binary search through all of the memblocks. Are you seeing real problems with the current code? Will