x86: set strong uncacheable where UC is really desired

Also use _PAGE_PWT for all the mappings which need uncache mapping.
Instead of existing PAT2 which is UC- (and can be overwritten by MTRRs),
we now use PAT3 which is strong uncacheable.

This makes it consistent with pgprot_noncached()

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/mm/ioremap_32.c b/arch/x86/mm/ioremap_32.c
index 0b27831..ef0f6a4 100644 (file)
--- a/arch/x86/mm/ioremap_32.c
+++ b/arch/x86/mm/ioremap_32.c
@@ -119,7 +119,7 @@ EXPORT_SYMBOL(__ioremap);
 void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
 {
        unsigned long last_addr;
-       void __iomem *p = __ioremap(phys_addr, size, _PAGE_PCD);
+       void __iomem *p = __ioremap(phys_addr, size, _PAGE_PCD | _PAGE_PWT);
        if (!p) 
                return p; 
 

diff --git a/arch/x86/mm/ioremap_64.c b/arch/x86/mm/ioremap_64.c
index d6cf149..2815ab6 100644 (file)
--- a/arch/x86/mm/ioremap_64.c
+++ b/arch/x86/mm/ioremap_64.c
@@ -138,7 +138,7 @@ EXPORT_SYMBOL(__ioremap);
 
 void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
 {
-       return __ioremap(phys_addr, size, _PAGE_PCD);
+       return __ioremap(phys_addr, size, _PAGE_PCD | _PAGE_PWT);
 }
 EXPORT_SYMBOL(ioremap_nocache);