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
);
14 void kunmap(struct page
*page
)
18 if (!PageHighMem(page
))
22 EXPORT_SYMBOL(kunmap
);
25 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
26 * no global lock is needed and because the kmap code must perform a global TLB
27 * invalidation when the kmap pool wraps.
29 * However when holding an atomic kmap it is not legal to sleep, so atomic
30 * kmaps are appropriate for short, tight code paths only.
32 void *kmap_atomic_prot(struct page
*page
, pgprot_t prot
)
37 /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
40 if (!PageHighMem(page
))
41 return page_address(page
);
43 type
= kmap_atomic_idx_push();
44 idx
= type
+ KM_TYPE_NR
*smp_processor_id();
45 vaddr
= __fix_to_virt(FIX_KMAP_BEGIN
+ idx
);
46 BUG_ON(!pte_none(*(kmap_pte
-idx
)));
47 set_pte(kmap_pte
-idx
, mk_pte(page
, prot
));
51 EXPORT_SYMBOL(kmap_atomic_prot
);
53 void *__kmap_atomic(struct page
*page
)
55 return kmap_atomic_prot(page
, kmap_prot
);
57 EXPORT_SYMBOL(__kmap_atomic
);
60 * This is the same as kmap_atomic() but can map memory that doesn't
61 * have a struct page associated with it.
63 void *kmap_atomic_pfn(unsigned long pfn
)
65 return kmap_atomic_prot_pfn(pfn
, kmap_prot
);
67 EXPORT_SYMBOL_GPL(kmap_atomic_pfn
);
69 void __kunmap_atomic(void *kvaddr
)
71 unsigned long vaddr
= (unsigned long) kvaddr
& PAGE_MASK
;
73 if (vaddr
>= __fix_to_virt(FIX_KMAP_END
) &&
74 vaddr
<= __fix_to_virt(FIX_KMAP_BEGIN
)) {
77 type
= kmap_atomic_idx_pop();
78 idx
= type
+ KM_TYPE_NR
* smp_processor_id();
80 #ifdef CONFIG_DEBUG_HIGHMEM
81 WARN_ON_ONCE(vaddr
!= __fix_to_virt(FIX_KMAP_BEGIN
+ idx
));
84 * Force other mappings to Oops if they'll try to access this
85 * pte without first remap it. Keeping stale mappings around
86 * is a bad idea also, in case the page changes cacheability
87 * attributes or becomes a protected page in a hypervisor.
89 kpte_clear_flush(kmap_pte
-idx
, vaddr
);
91 #ifdef CONFIG_DEBUG_HIGHMEM
93 BUG_ON(vaddr
< PAGE_OFFSET
);
94 BUG_ON(vaddr
>= (unsigned long)high_memory
);
100 EXPORT_SYMBOL(__kunmap_atomic
);
102 struct page
*kmap_atomic_to_page(void *ptr
)
104 unsigned long idx
, vaddr
= (unsigned long)ptr
;
107 if (vaddr
< FIXADDR_START
)
108 return virt_to_page(ptr
);
110 idx
= virt_to_fix(vaddr
);
111 pte
= kmap_pte
- (idx
- FIX_KMAP_BEGIN
);
112 return pte_page(*pte
);
114 EXPORT_SYMBOL(kmap_atomic_to_page
);
116 void __init
set_highmem_pages_init(void)
121 for_each_zone(zone
) {
122 unsigned long zone_start_pfn
, zone_end_pfn
;
124 if (!is_highmem(zone
))
127 zone_start_pfn
= zone
->zone_start_pfn
;
128 zone_end_pfn
= zone_start_pfn
+ zone
->spanned_pages
;
130 nid
= zone_to_nid(zone
);
131 printk(KERN_INFO
"Initializing %s for node %d (%08lx:%08lx)\n",
132 zone
->name
, nid
, zone_start_pfn
, zone_end_pfn
);
134 add_highpages_with_active_regions(nid
, zone_start_pfn
,
137 totalram_pages
+= totalhigh_pages
;