LXR linux/arch/x86/mm/highmem

   1#include <linux/highmem.h>
   2#include <linux/export.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        preempt_disable();
  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        preempt_enable();
 104}
 105EXPORT_SYMBOL(__kunmap_atomic);
 106
 107void __init set_highmem_pages_init(void)
 108{
 109        struct zone *zone;
 110        int nid;
 111
 112        /*
 113         * Explicitly reset zone->managed_pages because set_highmem_pages_init()
 114         * is invoked before free_all_bootmem()
 115         */
 116        reset_all_zones_managed_pages();
 117        for_each_zone(zone) {
 118                unsigned long zone_start_pfn, zone_end_pfn;
 119
 120                if (!is_highmem(zone))
 121                        continue;
 122
 123                zone_start_pfn = zone->zone_start_pfn;
 124                zone_end_pfn = zone_start_pfn + zone->spanned_pages;
 125
 126                nid = zone_to_nid(zone);
 127                printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
 128                                zone->name, nid, zone_start_pfn, zone_end_pfn);
 129
 130                add_highpages_with_active_regions(nid, zone_start_pfn,
 131                                 zone_end_pfn);
 132        }
 133}
 134