1 #include <linux/highmem.h>
2 #include <linux/module.h>
3 #include <linux/swap.h> /* for totalram_pages */
5 void *kmap(struct page
*page
)
8 if (!PageHighMem(page
))
9 return page_address(page
);
10 return kmap_high(page
);
13 void kunmap(struct page
*page
)
17 if (!PageHighMem(page
))
23 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
24 * no global lock is needed and because the kmap code must perform a global TLB
25 * invalidation when the kmap pool wraps.
27 * However when holding an atomic kmap is is not legal to sleep, so atomic
28 * kmaps are appropriate for short, tight code paths only.
30 void *kmap_atomic_prot(struct page
*page
, enum km_type type
, pgprot_t prot
)
32 enum fixed_addresses idx
;
35 /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
38 if (!PageHighMem(page
))
39 return page_address(page
);
41 debug_kmap_atomic(type
);
43 idx
= type
+ KM_TYPE_NR
*smp_processor_id();
44 vaddr
= __fix_to_virt(FIX_KMAP_BEGIN
+ idx
);
45 BUG_ON(!pte_none(*(kmap_pte
-idx
)));
46 set_pte(kmap_pte
-idx
, mk_pte(page
, prot
));
51 void *kmap_atomic(struct page
*page
, enum km_type type
)
53 return kmap_atomic_prot(page
, type
, kmap_prot
);
56 void kunmap_atomic(void *kvaddr
, enum km_type type
)
58 unsigned long vaddr
= (unsigned long) kvaddr
& PAGE_MASK
;
59 enum fixed_addresses idx
= type
+ KM_TYPE_NR
*smp_processor_id();
62 * Force other mappings to Oops if they'll try to access this pte
63 * without first remap it. Keeping stale mappings around is a bad idea
64 * also, in case the page changes cacheability attributes or becomes
65 * a protected page in a hypervisor.
67 if (vaddr
== __fix_to_virt(FIX_KMAP_BEGIN
+idx
))
68 kpte_clear_flush(kmap_pte
-idx
, vaddr
);
70 #ifdef CONFIG_DEBUG_HIGHMEM
71 BUG_ON(vaddr
< PAGE_OFFSET
);
72 BUG_ON(vaddr
>= (unsigned long)high_memory
);
80 * This is the same as kmap_atomic() but can map memory that doesn't
81 * have a struct page associated with it.
83 void *kmap_atomic_pfn(unsigned long pfn
, enum km_type type
)
85 return kmap_atomic_prot_pfn(pfn
, type
, kmap_prot
);
87 EXPORT_SYMBOL_GPL(kmap_atomic_pfn
); /* temporarily in use by i915 GEM until vmap */
89 struct page
*kmap_atomic_to_page(void *ptr
)
91 unsigned long idx
, vaddr
= (unsigned long)ptr
;
94 if (vaddr
< FIXADDR_START
)
95 return virt_to_page(ptr
);
97 idx
= virt_to_fix(vaddr
);
98 pte
= kmap_pte
- (idx
- FIX_KMAP_BEGIN
);
99 return pte_page(*pte
);
103 EXPORT_SYMBOL(kunmap
);
104 EXPORT_SYMBOL(kmap_atomic
);
105 EXPORT_SYMBOL(kunmap_atomic
);
107 void __init
set_highmem_pages_init(void)
112 for_each_zone(zone
) {
113 unsigned long zone_start_pfn
, zone_end_pfn
;
115 if (!is_highmem(zone
))
118 zone_start_pfn
= zone
->zone_start_pfn
;
119 zone_end_pfn
= zone_start_pfn
+ zone
->spanned_pages
;
121 nid
= zone_to_nid(zone
);
122 printk(KERN_INFO
"Initializing %s for node %d (%08lx:%08lx)\n",
123 zone
->name
, nid
, zone_start_pfn
, zone_end_pfn
);
125 add_highpages_with_active_regions(nid
, zone_start_pfn
,
128 totalram_pages
+= totalhigh_pages
;