1#include <linux/highmem.h>
2#include <linux/module.h>
3#include <linux/swap.h> /* for totalram_pages */
4#include <linux/bootmem.h>
5
6void *kmap(struct page *page)
7{
8	might_sleep();
9	if (!PageHighMem(page))
10		return page_address(page);
11	return kmap_high(page);
12}
13EXPORT_SYMBOL(kmap);
14
15void kunmap(struct page *page)
16{
17	if (in_interrupt())
18		BUG();
19	if (!PageHighMem(page))
20		return;
21	kunmap_high(page);
22}
23EXPORT_SYMBOL(kunmap);
24
25/*
26 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
27 * no global lock is needed and because the kmap code must perform a global TLB
28 * invalidation when the kmap pool wraps.
29 *
30 * However when holding an atomic kmap it is not legal to sleep, so atomic
31 * kmaps are appropriate for short, tight code paths only.
32 */
33void *kmap_atomic_prot(struct page *page, pgprot_t prot)
34{
35	unsigned long vaddr;
36	int idx, type;
37
38	/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
39	pagefault_disable();
40
41	if (!PageHighMem(page))
42		return page_address(page);
43
44	type = kmap_atomic_idx_push();
45	idx = type + KM_TYPE_NR*smp_processor_id();
46	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
47	BUG_ON(!pte_none(*(kmap_pte-idx)));
48	set_pte(kmap_pte-idx, mk_pte(page, prot));
49	arch_flush_lazy_mmu_mode();
50
51	return (void *)vaddr;
52}
53EXPORT_SYMBOL(kmap_atomic_prot);
54
55void *kmap_atomic(struct page *page)
56{
57	return kmap_atomic_prot(page, kmap_prot);
58}
59EXPORT_SYMBOL(kmap_atomic);
60
61/*
62 * This is the same as kmap_atomic() but can map memory that doesn't
63 * have a struct page associated with it.
64 */
65void *kmap_atomic_pfn(unsigned long pfn)
66{
67	return kmap_atomic_prot_pfn(pfn, kmap_prot);
68}
69EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
70
71void __kunmap_atomic(void *kvaddr)
72{
73	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
74
75	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
76	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
77		int idx, type;
78
79		type = kmap_atomic_idx();
80		idx = type + KM_TYPE_NR * smp_processor_id();
81
82#ifdef CONFIG_DEBUG_HIGHMEM
83		WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
84#endif
85		/*
86		 * Force other mappings to Oops if they'll try to access this
87		 * pte without first remap it.  Keeping stale mappings around
88		 * is a bad idea also, in case the page changes cacheability
89		 * attributes or becomes a protected page in a hypervisor.
90		 */
91		kpte_clear_flush(kmap_pte-idx, vaddr);
92		kmap_atomic_idx_pop();
93		arch_flush_lazy_mmu_mode();
94	}
95#ifdef CONFIG_DEBUG_HIGHMEM
96	else {
97		BUG_ON(vaddr < PAGE_OFFSET);
98		BUG_ON(vaddr >= (unsigned long)high_memory);
99	}
100#endif
101
102	pagefault_enable();
103}
104EXPORT_SYMBOL(__kunmap_atomic);
105
106struct page *kmap_atomic_to_page(void *ptr)
107{
108	unsigned long idx, vaddr = (unsigned long)ptr;
109	pte_t *pte;
110
111	if (vaddr < FIXADDR_START)
112		return virt_to_page(ptr);
113
114	idx = virt_to_fix(vaddr);
115	pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
116	return pte_page(*pte);
117}
118EXPORT_SYMBOL(kmap_atomic_to_page);
119
120void __init set_highmem_pages_init(void)
121{
122	struct zone *zone;
123	int nid;
124
125	/*
126	 * Explicitly reset zone->managed_pages because set_highmem_pages_init()
127	 * is invoked before free_all_bootmem()
128	 */
129	reset_all_zones_managed_pages();
130	for_each_zone(zone) {
131		unsigned long zone_start_pfn, zone_end_pfn;
132
133		if (!is_highmem(zone))
134			continue;
135
136		zone_start_pfn = zone->zone_start_pfn;
137		zone_end_pfn = zone_start_pfn + zone->spanned_pages;
138
139		nid = zone_to_nid(zone);
140		printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
141				zone->name, nid, zone_start_pfn, zone_end_pfn);
142
143		add_highpages_with_active_regions(nid, zone_start_pfn,
144				 zone_end_pfn);
145	}
146}
147