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Commit a361ee5c authored by Venkatesh Pallipadi's avatar Venkatesh Pallipadi Committed by Ingo Molnar
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x86: fix /dev/mem compatibility under PAT 

Add ioremap_default(), which gives a sane mapping without worrying about
type conflicts.

Use it in /dev/mem read in place of ioremap(), as with ioremap(),
any mapping of the region (other than UC_MINUS) will cause a conflict
and failure of /dev/mem read.

Should address the vbetest failure reported at:

  http://bugzilla.kernel.org/show_bug.cgi?id=11057



Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a1716d50

arch/x86/mm/ioremap.c

+24 −1
Original line number Diff line number Diff line
@@ -300,6 +300,29 @@ void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size) 
}

EXPORT_SYMBOL(ioremap_cache);



static void __iomem *ioremap_default(resource_size_t phys_addr,

					unsigned long size)

{

	unsigned long flags;

	void *ret;

	int err;



	/*

	 * - WB for WB-able memory and no other conflicting mappings

	 * - UC_MINUS for non-WB-able memory with no other conflicting mappings

	 * - Inherit from confliting mappings otherwise

	 */

	err = reserve_memtype(phys_addr, phys_addr + size, -1, &flags);

	if (err < 0)

		return NULL;



	ret = (void *) __ioremap_caller(phys_addr, size, flags,

					__builtin_return_address(0));



	free_memtype(phys_addr, phys_addr + size);

	return (void __iomem *)ret;

}



/**

 * iounmap - Free a IO remapping

 * @addr: virtual address from ioremap_*
@@ -365,7 +388,7 @@ void *xlate_dev_mem_ptr(unsigned long phys) 
	if (page_is_ram(start >> PAGE_SHIFT))

		return __va(phys);



	addr = (void *)ioremap(start, PAGE_SIZE);

	addr = (void *)ioremap_default(start, PAGE_SIZE);

	if (addr)

		addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK));