1 #include <linux/module.h> 2 #include <linux/highmem.h> 3 #include <linux/sched.h> 4 #include <linux/smp.h> 5 #include <asm/fixmap.h> 6 #include <asm/tlbflush.h> 7 8 static pte_t *kmap_pte; 9 10 unsigned long highstart_pfn, highend_pfn; 11 12 void *__kmap(struct page *page) 13 { 14 void *addr; 15 16 might_sleep(); 17 if (!PageHighMem(page)) 18 return page_address(page); 19 addr = kmap_high(page); 20 flush_tlb_one((unsigned long)addr); 21 22 return addr; 23 } 24 EXPORT_SYMBOL(__kmap); 25 26 void __kunmap(struct page *page) 27 { 28 BUG_ON(in_interrupt()); 29 if (!PageHighMem(page)) 30 return; 31 kunmap_high(page); 32 } 33 EXPORT_SYMBOL(__kunmap); 34 35 /* 36 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because 37 * no global lock is needed and because the kmap code must perform a global TLB 38 * invalidation when the kmap pool wraps. 39 * 40 * However when holding an atomic kmap is is not legal to sleep, so atomic 41 * kmaps are appropriate for short, tight code paths only. 42 */ 43 44 void *__kmap_atomic(struct page *page, enum km_type type) 45 { 46 enum fixed_addresses idx; 47 unsigned long vaddr; 48 49 /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ 50 pagefault_disable(); 51 if (!PageHighMem(page)) 52 return page_address(page); 53 54 debug_kmap_atomic(type); 55 idx = type + KM_TYPE_NR*smp_processor_id(); 56 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); 57 #ifdef CONFIG_DEBUG_HIGHMEM 58 BUG_ON(!pte_none(*(kmap_pte - idx))); 59 #endif 60 set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL)); 61 local_flush_tlb_one((unsigned long)vaddr); 62 63 return (void*) vaddr; 64 } 65 EXPORT_SYMBOL(__kmap_atomic); 66 67 void __kunmap_atomic(void *kvaddr, enum km_type type) 68 { 69 #ifdef CONFIG_DEBUG_HIGHMEM 70 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; 71 enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); 72 73 if (vaddr < FIXADDR_START) { // FIXME 74 pagefault_enable(); 75 return; 76 } 77 78 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); 79 80 /* 81 * force other mappings to Oops if they'll try to access 82 * this pte without first remap it 83 */ 84 pte_clear(&init_mm, vaddr, kmap_pte-idx); 85 local_flush_tlb_one(vaddr); 86 #endif 87 88 pagefault_enable(); 89 } 90 EXPORT_SYMBOL(__kunmap_atomic); 91 92 /* 93 * This is the same as kmap_atomic() but can map memory that doesn't 94 * have a struct page associated with it. 95 */ 96 void *kmap_atomic_pfn(unsigned long pfn, enum km_type type) 97 { 98 enum fixed_addresses idx; 99 unsigned long vaddr; 100 101 pagefault_disable(); 102 103 debug_kmap_atomic(type); 104 idx = type + KM_TYPE_NR*smp_processor_id(); 105 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); 106 set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL)); 107 flush_tlb_one(vaddr); 108 109 return (void*) vaddr; 110 } 111 112 struct page *__kmap_atomic_to_page(void *ptr) 113 { 114 unsigned long idx, vaddr = (unsigned long)ptr; 115 pte_t *pte; 116 117 if (vaddr < FIXADDR_START) 118 return virt_to_page(ptr); 119 120 idx = virt_to_fix(vaddr); 121 pte = kmap_pte - (idx - FIX_KMAP_BEGIN); 122 return pte_page(*pte); 123 } 124 125 void __init kmap_init(void) 126 { 127 unsigned long kmap_vstart; 128 129 /* cache the first kmap pte */ 130 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 131 kmap_pte = kmap_get_fixmap_pte(kmap_vstart); 132 } 133