1 #include <linux/module.h>
2 #include <linux/highmem.h>
3 #include <asm/tlbflush.h>
5 void *__kmap(struct page *page)
10 if (!PageHighMem(page))
11 return page_address(page);
12 addr = kmap_high(page);
13 flush_tlb_one((unsigned long)addr);
18 void __kunmap(struct page *page)
20 BUG_ON(in_interrupt());
21 if (!PageHighMem(page))
27 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
28 * no global lock is needed and because the kmap code must perform a global TLB
29 * invalidation when the kmap pool wraps.
31 * However when holding an atomic kmap is is not legal to sleep, so atomic
32 * kmaps are appropriate for short, tight code paths only.
35 void *__kmap_atomic(struct page *page, enum km_type type)
37 enum fixed_addresses idx;
40 /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
42 if (!PageHighMem(page))
43 return page_address(page);
45 idx = type + KM_TYPE_NR*smp_processor_id();
46 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
47 #ifdef CONFIG_DEBUG_HIGHMEM
48 BUG_ON(!pte_none(*(kmap_pte - idx)));
50 set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
51 local_flush_tlb_one((unsigned long)vaddr);
56 void __kunmap_atomic(void *kvaddr, enum km_type type)
58 #ifdef CONFIG_DEBUG_HIGHMEM
59 unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
60 enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
62 if (vaddr < FIXADDR_START) { // FIXME
67 BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
70 * force other mappings to Oops if they'll try to access
71 * this pte without first remap it
73 pte_clear(&init_mm, vaddr, kmap_pte-idx);
74 local_flush_tlb_one(vaddr);
81 * This is the same as kmap_atomic() but can map memory that doesn't
82 * have a struct page associated with it.
84 void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)
86 enum fixed_addresses idx;
91 idx = type + KM_TYPE_NR*smp_processor_id();
92 vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
93 set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));
99 struct page *__kmap_atomic_to_page(void *ptr)
101 unsigned long idx, vaddr = (unsigned long)ptr;
104 if (vaddr < FIXADDR_START)
105 return virt_to_page(ptr);
107 idx = virt_to_fix(vaddr);
108 pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
109 return pte_page(*pte);
112 EXPORT_SYMBOL(__kmap);
113 EXPORT_SYMBOL(__kunmap);
114 EXPORT_SYMBOL(__kmap_atomic);
115 EXPORT_SYMBOL(__kunmap_atomic);