Merge to Fedora kernel-2.6.6-1.422

[linux-2.6.git] / arch / i386 / mm / highmem.c

diff --git a/arch/i386/mm/highmem.c b/arch/i386/mm/highmem.c
index 5817532..83972da 100644 (file)
--- a/arch/i386/mm/highmem.c
+++ b/arch/i386/mm/highmem.c
@@ -41,12 +41,47 @@ void *kmap_atomic(struct page *page, enum km_type type)
        if (!pte_none(*(kmap_pte-idx)))
                BUG();
 #endif
-       set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
+       /*
+        * If the page is not a normal RAM page, then map it
+        * uncached to be on the safe side - it could be device
+        * memory that must not be prefetched:
+        */
+       if (PageReserved(page))
+               set_pte(kmap_pte-idx, mk_pte(page, kmap_prot_nocache));
+       else
+               set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
        __flush_tlb_one(vaddr);
 
        return (void*) vaddr;
 }
 
+/*
+ * page frame number based kmaps - useful for PCI mappings.
+ * NOTE: we map the page with the dont-cache flag.
+ */
+void *kmap_atomic_nocache_pfn(unsigned long pfn, enum km_type type)
+{
+       enum fixed_addresses idx;
+       unsigned long vaddr;
+
+       /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
+       inc_preempt_count();
+       if (pfn < highstart_pfn)
+               return pfn_to_kaddr(pfn);
+
+       idx = type + KM_TYPE_NR*smp_processor_id();
+       vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+#ifdef CONFIG_DEBUG_HIGHMEM
+       if (!pte_none(*(kmap_pte-idx)))
+               BUG();
+#endif
+       set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot_nocache));
+       __flush_tlb_one(vaddr);
+
+       return (void*) vaddr;
+}
+
+
 void kunmap_atomic(void *kvaddr, enum km_type type)
 {
 #ifdef CONFIG_DEBUG_HIGHMEM