include/asm-i386/atomic_kmap.h

   1 /*
   2  * atomic_kmap.h: temporary virtual kernel memory mappings
   3  *
   4  * Copyright (C) 2003 Ingo Molnar <mingo@redhat.com>
   5  */
   6
   7 #ifndef _ASM_ATOMIC_KMAP_H
   8 #define _ASM_ATOMIC_KMAP_H
   9
  10 #ifdef __KERNEL__
  11
  12 #include <linux/config.h>
  13 #include <asm/tlbflush.h>
  14
  15 #ifdef CONFIG_DEBUG_HIGHMEM
  16 #define HIGHMEM_DEBUG 1
  17 #else
  18 #define HIGHMEM_DEBUG 0
  19 #endif
  20
  21 extern pte_t *kmap_pte;
  22 #define kmap_prot PAGE_KERNEL
  23
  24 #define PKMAP_BASE (0xff000000UL)
  25 #define NR_SHARED_PMDS ((0xffffffff-PKMAP_BASE+1)/PMD_SIZE)
  26
  27 static inline unsigned long __kmap_atomic_vaddr(enum km_type type)
  28 {
  29         enum fixed_addresses idx;
  30
  31         idx = type + KM_TYPE_NR*smp_processor_id();
  32         return __fix_to_virt(FIX_KMAP_BEGIN + idx);
  33 }
  34
  35 static inline void *__kmap_atomic_noflush(struct page *page, enum km_type type)
  36 {
  37         enum fixed_addresses idx;
  38         unsigned long vaddr;
  39
  40         idx = type + KM_TYPE_NR*smp_processor_id();
  41         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  42         /*
  43          * NOTE: entries that rely on some secondary TLB-flush
  44          * effect must not be global:
  45          */
  46         set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
  47
  48         return (void*) vaddr;
  49 }
  50
  51 static inline void *__kmap_atomic(struct page *page, enum km_type type)
  52 {
  53         enum fixed_addresses idx;
  54         unsigned long vaddr;
  55
  56         idx = type + KM_TYPE_NR*smp_processor_id();
  57         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  58 #if HIGHMEM_DEBUG
  59         BUG_ON(!pte_none(*(kmap_pte-idx)));
  60 #else
  61         /*
  62          * Performance optimization - do not flush if the new
  63          * pte is the same as the old one:
  64          */
  65         if (pte_val(*(kmap_pte-idx)) == pte_val(mk_pte(page, kmap_prot)))
  66                 return (void *) vaddr;
  67 #endif
  68         set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
  69         __flush_tlb_one(vaddr);
  70
  71         return (void*) vaddr;
  72 }
  73
  74 static inline void __kunmap_atomic(void *kvaddr, enum km_type type)
  75 {
  76 #if HIGHMEM_DEBUG
  77         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
  78         enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
  79
  80         BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
  81         /*
  82          * force other mappings to Oops if they'll try to access
  83          * this pte without first remap it
  84          */
  85         pte_clear(kmap_pte-idx);
  86         __flush_tlb_one(vaddr);
  87 #endif
  88 }
  89
  90 #define __kunmap_atomic_type(type) \
  91                 __kunmap_atomic((void *)__kmap_atomic_vaddr(type), (type))
  92
  93 #endif /* __KERNEL__ */
  94
  95 #endif /* _ASM_ATOMIC_KMAP_H */