1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/highmem.h>
3 #include <linux/export.h>
4 #include <linux/swap.h> /* for totalram_pages */
5 #include <linux/memblock.h>
6
kmap(struct page * page)7 void *kmap(struct page *page)
8 {
9 might_sleep();
10 if (!PageHighMem(page))
11 return page_address(page);
12 return kmap_high(page);
13 }
14 EXPORT_SYMBOL(kmap);
15
kunmap(struct page * page)16 void kunmap(struct page *page)
17 {
18 if (in_interrupt())
19 BUG();
20 if (!PageHighMem(page))
21 return;
22 kunmap_high(page);
23 }
24 EXPORT_SYMBOL(kunmap);
25
26 /*
27 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
28 * no global lock is needed and because the kmap code must perform a global TLB
29 * invalidation when the kmap pool wraps.
30 *
31 * However when holding an atomic kmap it is not legal to sleep, so atomic
32 * kmaps are appropriate for short, tight code paths only.
33 */
kmap_atomic_prot(struct page * page,pgprot_t prot)34 void *kmap_atomic_prot(struct page *page, pgprot_t prot)
35 {
36 unsigned long vaddr;
37 int idx, type;
38
39 preempt_disable();
40 pagefault_disable();
41
42 if (!PageHighMem(page))
43 return page_address(page);
44
45 type = kmap_atomic_idx_push();
46 idx = type + KM_TYPE_NR*smp_processor_id();
47 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
48 BUG_ON(!pte_none(*(kmap_pte-idx)));
49 set_pte(kmap_pte-idx, mk_pte(page, prot));
50 arch_flush_lazy_mmu_mode();
51
52 return (void *)vaddr;
53 }
54 EXPORT_SYMBOL(kmap_atomic_prot);
55
kmap_atomic(struct page * page)56 void *kmap_atomic(struct page *page)
57 {
58 return kmap_atomic_prot(page, kmap_prot);
59 }
60 EXPORT_SYMBOL(kmap_atomic);
61
62 /*
63 * This is the same as kmap_atomic() but can map memory that doesn't
64 * have a struct page associated with it.
65 */
kmap_atomic_pfn(unsigned long pfn)66 void *kmap_atomic_pfn(unsigned long pfn)
67 {
68 return kmap_atomic_prot_pfn(pfn, kmap_prot);
69 }
70 EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
71
__kunmap_atomic(void * kvaddr)72 void __kunmap_atomic(void *kvaddr)
73 {
74 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
75
76 if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
77 vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
78 int idx, type;
79
80 type = kmap_atomic_idx();
81 idx = type + KM_TYPE_NR * smp_processor_id();
82
83 #ifdef CONFIG_DEBUG_HIGHMEM
84 WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
85 #endif
86 /*
87 * Force other mappings to Oops if they'll try to access this
88 * pte without first remap it. Keeping stale mappings around
89 * is a bad idea also, in case the page changes cacheability
90 * attributes or becomes a protected page in a hypervisor.
91 */
92 kpte_clear_flush(kmap_pte-idx, vaddr);
93 kmap_atomic_idx_pop();
94 arch_flush_lazy_mmu_mode();
95 }
96 #ifdef CONFIG_DEBUG_HIGHMEM
97 else {
98 BUG_ON(vaddr < PAGE_OFFSET);
99 BUG_ON(vaddr >= (unsigned long)high_memory);
100 }
101 #endif
102
103 pagefault_enable();
104 preempt_enable();
105 }
106 EXPORT_SYMBOL(__kunmap_atomic);
107
set_highmem_pages_init(void)108 void __init set_highmem_pages_init(void)
109 {
110 struct zone *zone;
111 int nid;
112
113 /*
114 * Explicitly reset zone->managed_pages because set_highmem_pages_init()
115 * is invoked before memblock_free_all()
116 */
117 reset_all_zones_managed_pages();
118 for_each_zone(zone) {
119 unsigned long zone_start_pfn, zone_end_pfn;
120
121 if (!is_highmem(zone))
122 continue;
123
124 zone_start_pfn = zone->zone_start_pfn;
125 zone_end_pfn = zone_start_pfn + zone->spanned_pages;
126
127 nid = zone_to_nid(zone);
128 printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
129 zone->name, nid, zone_start_pfn, zone_end_pfn);
130
131 add_highpages_with_active_regions(nid, zone_start_pfn,
132 zone_end_pfn);
133 }
134 }
135