LXR linux/arch/x86/mm/highmem

   1#include <linux/highmem.h>
   2#include <linux/module.h>
   3#include <linux/swap.h> /* for totalram_pages */
   4#include <linux/bootmem.h>
   5
   6void *kmap(struct page *page)
   7{
   8        might_sleep();
   9        if (!PageHighMem(page))
  10                return page_address(page);
  11        return kmap_high(page);
  12}
  13EXPORT_SYMBOL(kmap);
  14
  15void kunmap(struct page *page)
  16{
  17        if (in_interrupt())
  18                BUG();
  19        if (!PageHighMem(page))
  20                return;
  21        kunmap_high(page);
  22}
  23EXPORT_SYMBOL(kunmap);
  24
  25/*
  26 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
  27 * no global lock is needed and because the kmap code must perform a global TLB
  28 * invalidation when the kmap pool wraps.
  29 *
  30 * However when holding an atomic kmap it is not legal to sleep, so atomic
  31 * kmaps are appropriate for short, tight code paths only.
  32 */
  33void *kmap_atomic_prot(struct page *page, pgprot_t prot)
  34{
  35        unsigned long vaddr;
  36        int idx, type;
  37
  38        /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
  39        pagefault_disable();
  40
  41        if (!PageHighMem(page))
  42                return page_address(page);
  43
  44        type = kmap_atomic_idx_push();
  45        idx = type + KM_TYPE_NR*smp_processor_id();
  46        vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  47        BUG_ON(!pte_none(*(kmap_pte-idx)));
  48        set_pte(kmap_pte-idx, mk_pte(page, prot));
  49        arch_flush_lazy_mmu_mode();
  50
  51        return (void *)vaddr;
  52}
  53EXPORT_SYMBOL(kmap_atomic_prot);
  54
  55void *kmap_atomic(struct page *page)
  56{
  57        return kmap_atomic_prot(page, kmap_prot);
  58}
  59EXPORT_SYMBOL(kmap_atomic);
  60
  61/*
  62 * This is the same as kmap_atomic() but can map memory that doesn't
  63 * have a struct page associated with it.
  64 */
  65void *kmap_atomic_pfn(unsigned long pfn)
  66{
  67        return kmap_atomic_prot_pfn(pfn, kmap_prot);
  68}
  69EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
  70
  71void __kunmap_atomic(void *kvaddr)
  72{
  73        unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
  74
  75        if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
  76            vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
  77                int idx, type;
  78
  79                type = kmap_atomic_idx();
  80                idx = type + KM_TYPE_NR * smp_processor_id();
  81
  82#ifdef CONFIG_DEBUG_HIGHMEM
  83                WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
  84#endif
  85                /*
  86                 * Force other mappings to Oops if they'll try to access this
  87                 * pte without first remap it.  Keeping stale mappings around
  88                 * is a bad idea also, in case the page changes cacheability
  89                 * attributes or becomes a protected page in a hypervisor.
  90                 */
  91                kpte_clear_flush(kmap_pte-idx, vaddr);
  92                kmap_atomic_idx_pop();
  93                arch_flush_lazy_mmu_mode();
  94        }
  95#ifdef CONFIG_DEBUG_HIGHMEM
  96        else {
  97                BUG_ON(vaddr < PAGE_OFFSET);
  98                BUG_ON(vaddr >= (unsigned long)high_memory);
  99        }
 100#endif
 101
 102        pagefault_enable();
 103}
 104EXPORT_SYMBOL(__kunmap_atomic);
 105
 106struct page *kmap_atomic_to_page(void *ptr)
 107{
 108        unsigned long idx, vaddr = (unsigned long)ptr;
 109        pte_t *pte;
 110
 111        if (vaddr < FIXADDR_START)
 112                return virt_to_page(ptr);
 113
 114        idx = virt_to_fix(vaddr);
 115        pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
 116        return pte_page(*pte);
 117}
 118EXPORT_SYMBOL(kmap_atomic_to_page);
 119
 120void __init set_highmem_pages_init(void)
 121{
 122        struct zone *zone;
 123        int nid;
 124
 125        /*
 126         * Explicitly reset zone->managed_pages because set_highmem_pages_init()
 127         * is invoked before free_all_bootmem()
 128         */
 129        reset_all_zones_managed_pages();
 130        for_each_zone(zone) {
 131                unsigned long zone_start_pfn, zone_end_pfn;
 132
 133                if (!is_highmem(zone))
 134                        continue;
 135
 136                zone_start_pfn = zone->zone_start_pfn;
 137                zone_end_pfn = zone_start_pfn + zone->spanned_pages;
 138
 139                nid = zone_to_nid(zone);
 140                printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
 141                                zone->name, nid, zone_start_pfn, zone_end_pfn);
 142
 143                add_highpages_with_active_regions(nid, zone_start_pfn,
 144                                 zone_end_pfn);
 145        }
 146}
 147