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

Matthew Wilcox
2010-06-17T02:50:55Z

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))

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."