include/asm-sparc/highmem.h

   1 /*
   2  * highmem.h: virtual kernel memory mappings for high memory
   3  *
   4  * Used in CONFIG_HIGHMEM systems for memory pages which
   5  * are not addressable by direct kernel virtual adresses.
   6  *
   7  * Copyright (C) 1999 Gerhard Wichert, Siemens AG
   8  *                    Gerhard.Wichert@pdb.siemens.de
   9  *
  10  *
  11  * Redesigned the x86 32-bit VM architecture to deal with
  12  * up to 16 Terrabyte physical memory. With current x86 CPUs
  13  * we now support up to 64 Gigabytes physical RAM.
  14  *
  15  * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
  16  */
  17
  18 #ifndef _ASM_HIGHMEM_H
  19 #define _ASM_HIGHMEM_H
  20
  21 #ifdef __KERNEL__
  22
  23 #include <linux/init.h>
  24 #include <linux/interrupt.h>
  25 #include <asm/vaddrs.h>
  26 #include <asm/kmap_types.h>
  27 #include <asm/pgtable.h>
  28
  29 /* undef for production */
  30 #define HIGHMEM_DEBUG 1
  31
  32 /* declarations for highmem.c */
  33 extern unsigned long highstart_pfn, highend_pfn;
  34
  35 extern pte_t *kmap_pte;
  36 extern pgprot_t kmap_prot;
  37 extern pte_t *pkmap_page_table;
  38
  39 extern void kmap_init(void) __init;
  40
  41 /*
  42  * Right now we initialize only a single pte table. It can be extended
  43  * easily, subsequent pte tables have to be allocated in one physical
  44  * chunk of RAM.
  45  */
  46 #define LAST_PKMAP 1024
  47
  48 #define LAST_PKMAP_MASK (LAST_PKMAP-1)
  49 #define PKMAP_NR(virt)  ((virt-PKMAP_BASE) >> PAGE_SHIFT)
  50 #define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  51
  52 extern void *kmap_high(struct page *page);
  53 extern void kunmap_high(struct page *page);
  54
  55 static inline void *kmap(struct page *page)
  56 {
  57         if (in_interrupt())
  58                 BUG();
  59         if (page < highmem_start_page)
  60                 return page_address(page);
  61         return kmap_high(page);
  62 }
  63
  64 static inline void kunmap(struct page *page)
  65 {
  66         if (in_interrupt())
  67                 BUG();
  68         if (page < highmem_start_page)
  69                 return;
  70         kunmap_high(page);
  71 }
  72
  73 /*
  74  * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
  75  * gives a more generic (and caching) interface. But kmap_atomic can
  76  * be used in IRQ contexts, so in some (very limited) cases we need
  77  * it.
  78  */
  79 static inline void *kmap_atomic(struct page *page, enum km_type type)
  80 {
  81         unsigned long idx;
  82         unsigned long vaddr;
  83
  84         if (page < highmem_start_page)
  85                 return page_address(page);
  86
  87         idx = type + KM_TYPE_NR*smp_processor_id();
  88         vaddr = FIX_KMAP_BEGIN + idx * PAGE_SIZE;
  89
  90 /* XXX Fix - Anton */
  91 #if 0
  92         __flush_cache_one(vaddr);
  93 #else
  94         flush_cache_all();
  95 #endif
  96
  97 #if HIGHMEM_DEBUG
  98         if (!pte_none(*(kmap_pte+idx)))
  99                 BUG();
 100 #endif
 101         set_pte(kmap_pte+idx, mk_pte(page, kmap_prot));
 102 /* XXX Fix - Anton */
 103 #if 0
 104         __flush_tlb_one(vaddr);
 105 #else
 106         flush_tlb_all();
 107 #endif
 108
 109         return (void*) vaddr;
 110 }
 111
 112 static inline void kunmap_atomic(void *kvaddr, enum km_type type)
 113 {
 114 #if HIGHMEM_DEBUG
 115         unsigned long vaddr = (unsigned long) kvaddr;
 116         unsigned long idx = type + KM_TYPE_NR*smp_processor_id();
 117
 118 #if 0
 119         if (vaddr < FIXADDR_START) // FIXME
 120                 return;
 121 #endif
 122
 123         if (vaddr != FIX_KMAP_BEGIN + idx * PAGE_SIZE)
 124                 BUG();
 125
 126 /* XXX Fix - Anton */
 127 #if 0
 128         __flush_cache_one(vaddr);
 129 #else
 130         flush_cache_all();
 131 #endif
 132
 133         /*
 134          * force other mappings to Oops if they'll try to access
 135          * this pte without first remap it
 136          */
 137         pte_clear(kmap_pte+idx);
 138 /* XXX Fix - Anton */
 139 #if 0
 140         __flush_tlb_one(vaddr);
 141 #else
 142         flush_tlb_all();
 143 #endif
 144 #endif
 145 }
 146
 147 #endif /* __KERNEL__ */
 148
 149 #endif /* _ASM_HIGHMEM_H */