x86: add _PAGE_IOMAP pte flag for IO mappings

Use one of the software-defined PTE bits to indicate that a mapping is
intended for an IO address.  On native hardware this is irrelevent,
since a physical address is a physical address.  But in a virtual
environment, physical addresses are also virtualized, so there needs
to be some way to distinguish between pseudo-physical addresses and
actual hardware addresses; _PAGE_IOMAP indicates this intent.

By default, __supported_pte_mask masks out _PAGE_IOMAP, so it doesn't
even appear in the final pagetable.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 4 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 8cbeda15cd29..43c3b6896cd6 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -242,16 +242,16 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
         switch (prot_val) {
         case _PAGE_CACHE_UC:
         default:
-                prot = PAGE_KERNEL_NOCACHE;
+                prot = PAGE_KERNEL_IO_NOCACHE;
                 break;
         case _PAGE_CACHE_UC_MINUS:
-                prot = PAGE_KERNEL_UC_MINUS;
+                prot = PAGE_KERNEL_IO_UC_MINUS;
                 break;
         case _PAGE_CACHE_WC:
-                prot = PAGE_KERNEL_WC;
+                prot = PAGE_KERNEL_IO_WC;
                 break;
         case _PAGE_CACHE_WB:
-                prot = PAGE_KERNEL;
+                prot = PAGE_KERNEL_IO;
                 break;
         }