x86: fix /dev/mem mmap breakage when PAT is disabled

[linux-2.6-omap-h63xx.git] / arch / x86 / mm / pat.c

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 738fd0f2495823189daffbba1e5c836b227e6c25..eb1bf000d12e9b1aa1769284e263d43593095183 100644 (file)
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -481,12 +481,16 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
        return 1;
 }
 #else
+/* This check is needed to avoid cache aliasing when PAT is enabled */
 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 {
        u64 from = ((u64)pfn) << PAGE_SHIFT;
        u64 to = from + size;
        u64 cursor = from;
 
+       if (!pat_enabled)
+               return 1;
+
        while (cursor < to) {
                if (!devmem_is_allowed(pfn)) {
                        printk(KERN_INFO