From: catalin.marinas@arm•com (Catalin Marinas)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] arm64: Correct virt_addr_valid
Date: Tue, 17 Dec 2013 14:19:07 +0000 [thread overview]
Message-ID: <20131217141907.GJ32118@arm.com> (raw)
In-Reply-To: <52AF465D.8040000@codeaurora.org>
On Mon, Dec 16, 2013 at 06:28:45PM +0000, Laura Abbott wrote:
> On 12/13/2013 3:57 AM, Catalin Marinas wrote:
> > OK, I re-read it now.
> >
> >> Yes, I believe the point was that if we call virt_addr_valid on a
> >> not-direct-mapped address it should return false. We still need the
> >> range check on arm64 systems as well to ensure this.
> >
> > On arm64 we don't have highmem, so all RAM would be directly mapped (and
> > linear). Is there a case on a 64-bit architecture where pfn_valid() is
> > true but the memory not mapped? We don't unmap any memory which is
> > pfn_valid().
> >
>
> We don't have highmem but we still have a vmalloc region. Calling
> virt_to_page on a vmalloc address will not give a valid page so
> virt_addr_valid should return false on anything in the vmalloc region.
We are talking about pfn_valid(__pa(addr) >> PAGE_SHIFT). The __pa()
cannot be used on vmalloc addresses, I agree, but from a practical point
of view it doesn't return valid memory address. I can't think of a
scenario where it would (and if it does, your v2 patch should first
check the range before invoking __pa()).
--
Catalin
next prev parent reply other threads:[~2013-12-17 14:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-11 1:23 [PATCH] arm: Correct virt_addr_valid Laura Abbott
2013-12-11 1:23 ` [PATCH] arm64: " Laura Abbott
2013-12-11 10:44 ` Will Deacon
2013-12-11 11:06 ` Russell King - ARM Linux
2013-12-11 17:26 ` Will Deacon
2013-12-11 21:13 ` Russell King - ARM Linux
2013-12-12 17:57 ` Catalin Marinas
2013-12-12 18:02 ` Russell King - ARM Linux
2013-12-12 22:09 ` Laura Abbott
2013-12-13 11:57 ` Catalin Marinas
2013-12-16 18:28 ` Laura Abbott
2013-12-17 14:19 ` Catalin Marinas [this message]
2013-12-11 17:35 ` Laura Abbott
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