Add WB/UC check for early_ioremap

On ia64 system, the function early_ioremap returned an uncached memory
reference without checking whether this was consistent with existing
mappings. This causes efi error and the kernel failed during boot.  Add a
check to test whether memory has EFI_MEMORY_WB set.  Use the function
kern_mem_attribute() in early_iomap() function to provide appropriate
cacheable or uncacheable mapped address.

See the document Documentation/ia64/aliasing.txt for more details.

Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/mm/ioremap.c

@@ -16,7 +16,7 @@
 #include <asm/meminit.h>
 
 static inline void __iomem *
-__ioremap (unsigned long phys_addr)
+__ioremap_uc(unsigned long phys_addr)
 {
 	return (void __iomem *) (__IA64_UNCACHED_OFFSET | phys_addr);
 }
@@ -24,7 +24,11 @@ __ioremap (unsigned long phys_addr)
 void __iomem *
 early_ioremap (unsigned long phys_addr, unsigned long size)
 {
-	return __ioremap(phys_addr);
+	u64 attr;
+	attr = kern_mem_attribute(phys_addr, size);
+	if (attr & EFI_MEMORY_WB)
+		return (void __iomem *) phys_to_virt(phys_addr);
+	return __ioremap_uc(phys_addr);
 }
 
 void __iomem *
@@ -47,7 +51,7 @@ ioremap (unsigned long phys_addr, unsigned long size)
 	if (attr & EFI_MEMORY_WB)
 		return (void __iomem *) phys_to_virt(phys_addr);
 	else if (attr & EFI_MEMORY_UC)
-		return __ioremap(phys_addr);
+		return __ioremap_uc(phys_addr);
 
 	/*
 	 * Some chipsets don't support UC access to memory.  If
@@ -93,7 +97,7 @@ ioremap (unsigned long phys_addr, unsigned long size)
 		return (void __iomem *) (offset + (char __iomem *)addr);
 	}
 
-	return __ioremap(phys_addr);
+	return __ioremap_uc(phys_addr);
 }
 EXPORT_SYMBOL(ioremap);
 
@@ -103,7 +107,7 @@ ioremap_nocache (unsigned long phys_addr, unsigned long size)
 	if (kern_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)
 		return NULL;
 
-	return __ioremap(phys_addr);
+	return __ioremap_uc(phys_addr);
 }
 EXPORT_SYMBOL(ioremap_nocache);