arch/sparc/include/asm/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 addresses.
   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/interrupt.h>
  24 #include <asm/vaddrs.h>
  25 #include <asm/kmap_types.h>
  26 #include <asm/pgtable.h>
  27
  28 /* declarations for highmem.c */
  29 extern unsigned long highstart_pfn, highend_pfn;
  30
  31 extern pgprot_t kmap_prot;
  32 extern pte_t *pkmap_page_table;
  33
  34 extern void kmap_init(void) __init;
  35
  36 /*
  37  * Right now we initialize only a single pte table. It can be extended
  38  * easily, subsequent pte tables have to be allocated in one physical
  39  * chunk of RAM.  Currently the simplest way to do this is to align the
  40  * pkmap region on a pagetable boundary (4MB).
  41  */
  42 #define LAST_PKMAP 1024
  43 #define PKMAP_SIZE (LAST_PKMAP << PAGE_SHIFT)
  44 #define PKMAP_BASE PMD_ALIGN(SRMMU_NOCACHE_VADDR + (SRMMU_MAX_NOCACHE_PAGES << PAGE_SHIFT))
  45
  46 #define LAST_PKMAP_MASK (LAST_PKMAP - 1)
  47 #define PKMAP_NR(virt)  ((virt - PKMAP_BASE) >> PAGE_SHIFT)
  48 #define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  49
  50 #define PKMAP_END (PKMAP_ADDR(LAST_PKMAP))
  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         BUG_ON(in_interrupt());
  58         if (!PageHighMem(page))
  59                 return page_address(page);
  60         return kmap_high(page);
  61 }
  62
  63 static inline void kunmap(struct page *page)
  64 {
  65         BUG_ON(in_interrupt());
  66         if (!PageHighMem(page))
  67                 return;
  68         kunmap_high(page);
  69 }
  70
  71 extern void *kmap_atomic(struct page *page);
  72 extern void __kunmap_atomic(void *kvaddr);
  73
  74 #define flush_cache_kmaps()     flush_cache_all()
  75
  76 #endif /* __KERNEL__ */
  77
  78 #endif /* _ASM_HIGHMEM_H */