LXR linux/arch/microblaze/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 Terabyte 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#ifndef _ASM_HIGHMEM_H
  18#define _ASM_HIGHMEM_H
  19
  20#ifdef __KERNEL__
  21
  22#include <linux/init.h>
  23#include <linux/interrupt.h>
  24#include <linux/uaccess.h>
  25#include <asm/fixmap.h>
  26
  27extern pte_t *kmap_pte;
  28extern pgprot_t kmap_prot;
  29extern pte_t *pkmap_page_table;
  30
  31/*
  32 * Right now we initialize only a single pte table. It can be extended
  33 * easily, subsequent pte tables have to be allocated in one physical
  34 * chunk of RAM.
  35 */
  36/*
  37 * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
  38 * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
  39 * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
  40 * in case of 16K/64K/256K page sizes.
  41 */
  42
  43#define PKMAP_ORDER     PTE_SHIFT
  44#define LAST_PKMAP      (1 << PKMAP_ORDER)
  45
  46#define PKMAP_BASE      ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
  47                                                                & PMD_MASK)
  48
  49#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
  50#define PKMAP_NR(virt)  ((virt - PKMAP_BASE) >> PAGE_SHIFT)
  51#define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  52
  53extern void *kmap_high(struct page *page);
  54extern void kunmap_high(struct page *page);
  55extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
  56extern void __kunmap_atomic(void *kvaddr);
  57
  58static inline void *kmap(struct page *page)
  59{
  60        might_sleep();
  61        if (!PageHighMem(page))
  62                return page_address(page);
  63        return kmap_high(page);
  64}
  65
  66static inline void kunmap(struct page *page)
  67{
  68        BUG_ON(in_interrupt());
  69        if (!PageHighMem(page))
  70                return;
  71        kunmap_high(page);
  72}
  73
  74static inline void *kmap_atomic(struct page *page)
  75{
  76        return kmap_atomic_prot(page, kmap_prot);
  77}
  78
  79static inline struct page *kmap_atomic_to_page(void *ptr)
  80{
  81        unsigned long idx, vaddr = (unsigned long) ptr;
  82        pte_t *pte;
  83
  84        if (vaddr < FIXADDR_START)
  85                return virt_to_page(ptr);
  86
  87        idx = virt_to_fix(vaddr);
  88        pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
  89        return pte_page(*pte);
  90}
  91
  92#define flush_cache_kmaps()     { flush_icache(); flush_dcache(); }
  93
  94#endif /* __KERNEL__ */
  95
  96#endif /* _ASM_HIGHMEM_H */
  97