1 #include <linux/highmem.h> 2 #include <linux/module.h> 3 #include <linux/swap.h> /* for totalram_pages */ 4 #include <linux/bootmem.h> 5 6 void *kmap(struct page *page) 7 { 8 might_sleep(); 9 if (!PageHighMem(page)) 10 return page_address(page); 11 return kmap_high(page); 12 } 13 EXPORT_SYMBOL(kmap); 14 15 void kunmap(struct page *page) 16 { 17 if (in_interrupt()) 18 BUG(); 19 if (!PageHighMem(page)) 20 return; 21 kunmap_high(page); 22 } 23 EXPORT_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 */ 33 void *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 } 53 EXPORT_SYMBOL(kmap_atomic_prot); 54 55 void *kmap_atomic(struct page *page) 56 { 57 return kmap_atomic_prot(page, kmap_prot); 58 } 59 EXPORT_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 */ 65 void *kmap_atomic_pfn(unsigned long pfn) 66 { 67 return kmap_atomic_prot_pfn(pfn, kmap_prot); 68 } 69 EXPORT_SYMBOL_GPL(kmap_atomic_pfn); 70 71 void __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 } 104 EXPORT_SYMBOL(__kunmap_atomic); 105 106 struct 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 } 118 EXPORT_SYMBOL(kmap_atomic_to_page); 119 120 void __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