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