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 arch_flush_lazy_mmu_mode(); 49 50 return (void *)vaddr; 51 } 52 EXPORT_SYMBOL(kmap_atomic_prot); 53 54 void *kmap_atomic(struct page *page) 55 { 56 return kmap_atomic_prot(page, kmap_prot); 57 } 58 EXPORT_SYMBOL(kmap_atomic); 59 60 /* 61 * This is the same as kmap_atomic() but can map memory that doesn't 62 * have a struct page associated with it. 63 */ 64 void *kmap_atomic_pfn(unsigned long pfn) 65 { 66 return kmap_atomic_prot_pfn(pfn, kmap_prot); 67 } 68 EXPORT_SYMBOL_GPL(kmap_atomic_pfn); 69 70 void __kunmap_atomic(void *kvaddr) 71 { 72 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; 73 74 if (vaddr >= __fix_to_virt(FIX_KMAP_END) && 75 vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) { 76 int idx, type; 77 78 type = kmap_atomic_idx(); 79 idx = type + KM_TYPE_NR * smp_processor_id(); 80 81 #ifdef CONFIG_DEBUG_HIGHMEM 82 WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); 83 #endif 84 /* 85 * Force other mappings to Oops if they'll try to access this 86 * pte without first remap it. Keeping stale mappings around 87 * is a bad idea also, in case the page changes cacheability 88 * attributes or becomes a protected page in a hypervisor. 89 */ 90 kpte_clear_flush(kmap_pte-idx, vaddr); 91 kmap_atomic_idx_pop(); 92 arch_flush_lazy_mmu_mode(); 93 } 94 #ifdef CONFIG_DEBUG_HIGHMEM 95 else { 96 BUG_ON(vaddr < PAGE_OFFSET); 97 BUG_ON(vaddr >= (unsigned long)high_memory); 98 } 99 #endif 100 101 pagefault_enable(); 102 } 103 EXPORT_SYMBOL(__kunmap_atomic); 104 105 struct page *kmap_atomic_to_page(void *ptr) 106 { 107 unsigned long idx, vaddr = (unsigned long)ptr; 108 pte_t *pte; 109 110 if (vaddr < FIXADDR_START) 111 return virt_to_page(ptr); 112 113 idx = virt_to_fix(vaddr); 114 pte = kmap_pte - (idx - FIX_KMAP_BEGIN); 115 return pte_page(*pte); 116 } 117 EXPORT_SYMBOL(kmap_atomic_to_page); 118 119 void __init set_highmem_pages_init(void) 120 { 121 struct zone *zone; 122 int nid; 123 124 for_each_zone(zone) { 125 unsigned long zone_start_pfn, zone_end_pfn; 126 127 if (!is_highmem(zone)) 128 continue; 129 130 zone_start_pfn = zone->zone_start_pfn; 131 zone_end_pfn = zone_start_pfn + zone->spanned_pages; 132 133 nid = zone_to_nid(zone); 134 printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n", 135 zone->name, nid, zone_start_pfn, zone_end_pfn); 136 137 add_highpages_with_active_regions(nid, zone_start_pfn, 138 zone_end_pfn); 139 } 140 } 141