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 #define kmap_prot_nocache PAGE_KERNEL_NOCACHE
  24
  25 #define PKMAP_BASE (0xff000000UL)
  26 #define NR_SHARED_PMDS ((0xffffffff-PKMAP_BASE+1)/PMD_SIZE)
  27
  28 static inline unsigned long __kmap_atomic_vaddr(enum km_type type)
  29 {
  30         enum fixed_addresses idx;
  31
  32         idx = type + KM_TYPE_NR*smp_processor_id();
  33         return __fix_to_virt(FIX_KMAP_BEGIN + idx);
  34 }
  35
  36 static inline void *__kmap_atomic_noflush(struct page *page, enum km_type type)
  37 {
  38         enum fixed_addresses idx;
  39         unsigned long vaddr;
  40
  41         idx = type + KM_TYPE_NR*smp_processor_id();
  42         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  43         /*
  44          * NOTE: entries that rely on some secondary TLB-flush
  45          * effect must not be global:
  46          */
  47         set_pte(kmap_pte-idx, mk_pte(page, PAGE_KERNEL));
  48
  49         return (void*) vaddr;
  50 }
  51
  52 static inline void *__kmap_atomic(struct page *page, enum km_type type)
  53 {
  54         enum fixed_addresses idx;
  55         unsigned long vaddr;
  56
  57         idx = type + KM_TYPE_NR*smp_processor_id();
  58         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  59 #if HIGHMEM_DEBUG
  60         BUG_ON(!pte_none(*(kmap_pte-idx)));
  61 #else
  62         /*
  63          * Performance optimization - do not flush if the new
  64          * pte is the same as the old one:
  65          */
  66         if (pte_val(*(kmap_pte-idx)) == pte_val(mk_pte(page, kmap_prot)))
  67                 return (void *) vaddr;
  68 #endif
  69         set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
  70         __flush_tlb_one(vaddr);
  71
  72         return (void*) vaddr;
  73 }
  74
  75 static inline void __kunmap_atomic(void *kvaddr, enum km_type type)
  76 {
  77 #if HIGHMEM_DEBUG
  78         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
  79         enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
  80
  81         BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
  82         /*
  83          * force other mappings to Oops if they'll try to access
  84          * this pte without first remap it
  85          */
  86         pte_clear(kmap_pte-idx);
  87         __flush_tlb_one(vaddr);
  88 #endif
  89 }
  90
  91 #define __kunmap_atomic_type(type) \
  92                 __kunmap_atomic((void *)__kmap_atomic_vaddr(type), (type))
  93
  94 #endif /* __KERNEL__ */
  95
  96 #endif /* _ASM_ATOMIC_KMAP_H */