Re: [PATCH 2/4] x86: ioremap: fix physical address check

[Kenji Kaneshige]

(2010/06/15 5:16), Rolf Eike Beer wrote:
> Kenji Kaneshige wrote:
> > (2010/06/14 18:13), Kenji Kaneshige wrote:
> > > Thank you Hiroyuki.
> > >
> > > So many bugs in ioremap()...
> > >
> > > Will try with those bugs fixed.
> > >
> > > Thanks,
> > > Kenji Kaneshige
> >
> > The problem seems to be fixed by the following patch. This is still
> > under testing. I will post the patch as v2 after testing.
> >
> > Thanks,
> > Kenji Kaneshige
> >
> >
> > Current x86 ioremap() doesn't handle physical address higher than
> > 32-bit properly in X86_32 PAE mode. When physical address higher than
> > 32-bit is passed to ioremap(), higher 32-bits in physical address is
> > cleared wrongly. Due to this bug, ioremap() can map wrong address to
> > linear address space.
> >
> > In my case, 64-bit MMIO region was assigned to a PCI device (ioat
> > device) on my system. Because of the ioremap()'s bug, wrong physical
> > address (instead of MMIO region) was mapped to linear address space.
> > Because of this, loading ioatdma driver caused unexpected behavior
> > (kernel panic, kernel hangup, ...).
> >
> > Signed-off-by: Kenji Kaneshige<kaneshige.kenji@xxxxxxxxxxxxxx>
> >
> > ---
> >   arch/x86/mm/ioremap.c   |   11 +++++------
> >   include/linux/io.h      |    4 ++--
> >   include/linux/vmalloc.h |    2 +-
> >   lib/ioremap.c           |   10 +++++-----
> >   4 files changed, 13 insertions(+), 14 deletions(-)
> >
> > Index: linux-2.6.34/arch/x86/mm/ioremap.c
> > ===================================================================
> > --- linux-2.6.34.orig/arch/x86/mm/ioremap.c
> > +++ linux-2.6.34/arch/x86/mm/ioremap.c
> > @@ -62,7 +62,8 @@ int ioremap_change_attr(unsigned long va
> >   static void __iomem *__ioremap_caller(resource_size_t phys_addr,
> >   		unsigned long size, unsigned long prot_val, void *caller)
> >   {
> > -	unsigned long pfn, offset, vaddr;
> > +	u64 pfn, last_pfn;
> > +	unsigned long offset, vaddr;
> >   	resource_size_t last_addr;
> >   	const resource_size_t unaligned_phys_addr = phys_addr;
> >   	const unsigned long unaligned_size = size;
>
> Why do you use u64 and not resource_size_t for those? That way this would not
> be needlessly big for "real" 32 bit platforms.

Thank you for your comment. The reason was I found other code that uses
u64 for pfn in other code. But yes, I will change that.

Thanks,
Kenji Kaneshige


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