1 #include <linux/highmem.h> 2 #include <linux/module.h> 3 #include <linux/swap.h> /* for totalram_pages */ 4 5 void *kmap(struct page *page) 6 { 7 might_sleep(); 8 if (!PageHighMem(page)) 9 return page_address(page); 10 return kmap_high(page); 11 } 12 EXPORT_SYMBOL(kmap); 13 14 void kunmap(struct page *page) 15 { 16 if (in_interrupt()) 17 BUG(); 18 if (!PageHighMem(page)) 19 return; 20 kunmap_high(page); 21 } 22 EXPORT_SYMBOL(kunmap); 23 24 /* 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. 28 * 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. 31 */ 32 void *kmap_atomic_prot(struct page *page, pgprot_t prot) 33 { 34 unsigned long vaddr; 35 int idx, type; 36 37 /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ 38 pagefault_disable(); 39 40 if (!PageHighMem(page)) 41 return page_address(page); 42 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)); 48 49 return (void *)vaddr; 50 } 51 EXPORT_SYMBOL(kmap_atomic_prot); 52 53 void *__kmap_atomic(struct page *page) 54 { 55 return kmap_atomic_prot(page, kmap_prot); 56 } 57 EXPORT_SYMBOL(__kmap_atomic); 58 59 /* 60 * This is the same as kmap_atomic() but can map memory that doesn't 61 * have a struct page associated with it. 62 */ 63 void *kmap_atomic_pfn(unsigned long pfn) 64 { 65 return kmap_atomic_prot_pfn(pfn, kmap_prot); 66 } 67 EXPORT_SYMBOL_GPL(kmap_atomic_pfn); 68 69 void __kunmap_atomic(void *kvaddr) 70 { 71 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; 72 73 if (vaddr >= __fix_to_virt(FIX_KMAP_END) && 74 vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) { 75 int idx, type; 76 77 type = kmap_atomic_idx(); 78 idx = type + KM_TYPE_NR * smp_processor_id(); 79 80 #ifdef CONFIG_DEBUG_HIGHMEM 81 WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); 82 #endif 83 /* 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. 88 */ 89 kpte_clear_flush(kmap_pte-idx, vaddr); 90 kmap_atomic_idx_pop(); 91 } 92 #ifdef CONFIG_DEBUG_HIGHMEM 93 else { 94 BUG_ON(vaddr < PAGE_OFFSET); 95 BUG_ON(vaddr >= (unsigned long)high_memory); 96 } 97 #endif 98 99 pagefault_enable(); 100 } 101 EXPORT_SYMBOL(__kunmap_atomic); 102 103 struct page *kmap_atomic_to_page(void *ptr) 104 { 105 unsigned long idx, vaddr = (unsigned long)ptr; 106 pte_t *pte; 107 108 if (vaddr < FIXADDR_START) 109 return virt_to_page(ptr); 110 111 idx = virt_to_fix(vaddr); 112 pte = kmap_pte - (idx - FIX_KMAP_BEGIN); 113 return pte_page(*pte); 114 } 115 EXPORT_SYMBOL(kmap_atomic_to_page); 116 117 void __init set_highmem_pages_init(void) 118 { 119 struct zone *zone; 120 int nid; 121 122 for_each_zone(zone) { 123 unsigned long zone_start_pfn, zone_end_pfn; 124 125 if (!is_highmem(zone)) 126 continue; 127 128 zone_start_pfn = zone->zone_start_pfn; 129 zone_end_pfn = zone_start_pfn + zone->spanned_pages; 130 131 nid = zone_to_nid(zone); 132 printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n", 133 zone->name, nid, zone_start_pfn, zone_end_pfn); 134 135 add_highpages_with_active_regions(nid, zone_start_pfn, 136 zone_end_pfn); 137 } 138 totalram_pages += totalhigh_pages; 139 } 140