1 #include <linux/module.h>
2 #include <linux/highmem.h>
3 #include <asm/fixmap.h>
4 #include <asm/tlbflush.h>
6 static pte_t
*kmap_pte
;
8 unsigned long highstart_pfn
, highend_pfn
;
10 void *__kmap(struct page
*page
)
15 if (!PageHighMem(page
))
16 return page_address(page
);
17 addr
= kmap_high(page
);
18 flush_tlb_one((unsigned long)addr
);
22 EXPORT_SYMBOL(__kmap
);
24 void __kunmap(struct page
*page
)
26 BUG_ON(in_interrupt());
27 if (!PageHighMem(page
))
31 EXPORT_SYMBOL(__kunmap
);
34 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
35 * no global lock is needed and because the kmap code must perform a global TLB
36 * invalidation when the kmap pool wraps.
38 * However when holding an atomic kmap is is not legal to sleep, so atomic
39 * kmaps are appropriate for short, tight code paths only.
42 void *__kmap_atomic(struct page
*page
, enum km_type type
)
44 enum fixed_addresses idx
;
47 /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
49 if (!PageHighMem(page
))
50 return page_address(page
);
52 debug_kmap_atomic(type
);
53 idx
= type
+ KM_TYPE_NR
*smp_processor_id();
54 vaddr
= __fix_to_virt(FIX_KMAP_BEGIN
+ idx
);
55 #ifdef CONFIG_DEBUG_HIGHMEM
56 BUG_ON(!pte_none(*(kmap_pte
- idx
)));
58 set_pte(kmap_pte
-idx
, mk_pte(page
, PAGE_KERNEL
));
59 local_flush_tlb_one((unsigned long)vaddr
);
63 EXPORT_SYMBOL(__kmap_atomic
);
65 void __kunmap_atomic(void *kvaddr
, enum km_type type
)
67 #ifdef CONFIG_DEBUG_HIGHMEM
68 unsigned long vaddr
= (unsigned long) kvaddr
& PAGE_MASK
;
69 enum fixed_addresses idx
= type
+ KM_TYPE_NR
*smp_processor_id();
71 if (vaddr
< FIXADDR_START
) { // FIXME
76 BUG_ON(vaddr
!= __fix_to_virt(FIX_KMAP_BEGIN
+ idx
));
79 * force other mappings to Oops if they'll try to access
80 * this pte without first remap it
82 pte_clear(&init_mm
, vaddr
, kmap_pte
-idx
);
83 local_flush_tlb_one(vaddr
);
88 EXPORT_SYMBOL(__kunmap_atomic
);
91 * This is the same as kmap_atomic() but can map memory that doesn't
92 * have a struct page associated with it.
94 void *kmap_atomic_pfn(unsigned long pfn
, enum km_type type
)
96 enum fixed_addresses idx
;
101 debug_kmap_atomic(type
);
102 idx
= type
+ KM_TYPE_NR
*smp_processor_id();
103 vaddr
= __fix_to_virt(FIX_KMAP_BEGIN
+ idx
);
104 set_pte(kmap_pte
-idx
, pfn_pte(pfn
, PAGE_KERNEL
));
105 flush_tlb_one(vaddr
);
107 return (void*) vaddr
;
110 struct page
*__kmap_atomic_to_page(void *ptr
)
112 unsigned long idx
, vaddr
= (unsigned long)ptr
;
115 if (vaddr
< FIXADDR_START
)
116 return virt_to_page(ptr
);
118 idx
= virt_to_fix(vaddr
);
119 pte
= kmap_pte
- (idx
- FIX_KMAP_BEGIN
);
120 return pte_page(*pte
);
123 void __init
kmap_init(void)
125 unsigned long kmap_vstart
;
127 /* cache the first kmap pte */
128 kmap_vstart
= __fix_to_virt(FIX_KMAP_BEGIN
);
129 kmap_pte
= kmap_get_fixmap_pte(kmap_vstart
);