Re: [PATCH 1/2] x86: ioremap: fix wrong physical address handling

[Kenji Kaneshige]

(2010/06/17 11:50), Matthew Wilcox wrote:
> On Thu, Jun 17, 2010 at 10:30:06AM +0900, Kenji Kaneshige wrote:
> > Index: linux-2.6.34/arch/x86/mm/ioremap.c
> > ===================================================================
> > --- linux-2.6.34.orig/arch/x86/mm/ioremap.c	2010-06-15 04:43:00.978332015 +0900
> > +++ linux-2.6.34/arch/x86/mm/ioremap.c	2010-06-15 05:32:59.291693007 +0900
> > @@ -62,8 +62,8 @@
> >   static void __iomem *__ioremap_caller(resource_size_t phys_addr,
> >   		unsigned long size, unsigned long prot_val, void *caller)
> >   {
> > -	unsigned long pfn, offset, vaddr;
> > -	resource_size_t last_addr;
> > +	unsigned long offset, vaddr;
> > +	resource_size_t pfn, last_pfn, last_addr;
>
> I have a hard time understanding this change.  pfn is always a physical
> address shifted by PAGE_SHIFT.  So a 32-bit pfn supports up to 44-bit
> physical addresses.  Are your addresses above 44-bits?
>
> > @@ -115,7 +113,7 @@
> >   	 * Mappings have to be page-aligned
> >   	 */
> >   	offset = phys_addr&  ~PAGE_MASK;
> > -	phys_addr&= PAGE_MASK;
> > +	phys_addr = (phys_addr>>  PAGE_SHIFT)<<  PAGE_SHIFT;
>
> I'd rather see PAGE_MASK fixed.  Would this work?
>
>   #define PAGE_SIZE       (_AC(1,UL)<<  PAGE_SHIFT)
> -#define PAGE_MASK       (~(PAGE_SIZE-1))
> +#define PAGE_MASK       (~(PAGE_SIZE-1ULL))

I think it should work. But I'm worrying about regressions.
Now I think using PHYSICAL_PAGE_MASK (as my v.1 patch did) is good idea
again. What do you think about this?

Thanks,
Kenji Kaneshige

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