arch/x86/mm/highmem_32-xen.c

   1 #include <linux/highmem.h>
   2 #include <linux/module.h>
   3 #include <linux/swap.h> /* for totalram_pages */
   4
   5 void *kmap(struct page *page)
   6 {
   7         might_sleep();
   8         if (!PageHighMem(page))
   9                 return page_address(page);
  10         return kmap_high(page);
  11 }
  12 EXPORT_SYMBOL(kmap);
  13
  14 void kunmap(struct page *page)
  15 {
  16         if (in_interrupt())
  17                 BUG();
  18         if (!PageHighMem(page))
  19                 return;
  20         kunmap_high(page);
  21 }
  22 EXPORT_SYMBOL(kunmap);
  23
  24 /*
  25  * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
  26  * no global lock is needed and because the kmap code must perform a global TLB
  27  * invalidation when the kmap pool wraps.
  28  *
  29  * However when holding an atomic kmap it is not legal to sleep, so atomic
  30  * kmaps are appropriate for short, tight code paths only.
  31  */
  32 void *kmap_atomic_prot(struct page *page, pgprot_t prot)
  33 {
  34         unsigned long vaddr;
  35         int idx, type;
  36
  37         /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
  38         pagefault_disable();
  39
  40         if (!PageHighMem(page))
  41                 return page_address(page);
  42
  43         type = kmap_atomic_idx_push();
  44         idx = type + KM_TYPE_NR*smp_processor_id();
  45         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  46         BUG_ON(!pte_none(*(kmap_pte-idx)));
  47         set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
  48         /*arch_flush_lazy_mmu_mode();*/
  49
  50         return (void *)vaddr;
  51 }
  52 EXPORT_SYMBOL(kmap_atomic_prot);
  53
  54 void *kmap_atomic(struct page *page)
  55 {
  56         return kmap_atomic_prot(page, kmap_prot);
  57 }
  58 EXPORT_SYMBOL(kmap_atomic);
  59
  60 /*
  61  * This is the same as kmap_atomic() but can map memory that doesn't
  62  * have a struct page associated with it.
  63  */
  64 void *kmap_atomic_pfn(unsigned long pfn)
  65 {
  66         return kmap_atomic_prot_pfn(pfn, kmap_prot);
  67 }
  68 EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
  69
  70 void __kunmap_atomic(void *kvaddr)
  71 {
  72         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
  73
  74         if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
  75             vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
  76                 int idx, type;
  77
  78                 type = kmap_atomic_idx();
  79                 idx = type + KM_TYPE_NR * smp_processor_id();
  80
  81 #ifdef CONFIG_DEBUG_HIGHMEM
  82                 WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
  83 #endif
  84                 /*
  85                  * Force other mappings to Oops if they'll try to access this
  86                  * pte without first remap it.  Keeping stale mappings around
  87                  * is a bad idea also, in case the page changes cacheability
  88                  * attributes or becomes a protected page in a hypervisor.
  89                  */
  90                 kpte_clear_flush(kmap_pte-idx, vaddr);
  91                 kmap_atomic_idx_pop();
  92                 /*arch_flush_lazy_mmu_mode();*/
  93         }
  94 #ifdef CONFIG_DEBUG_HIGHMEM
  95         else {
  96                 BUG_ON(vaddr < PAGE_OFFSET);
  97                 BUG_ON(vaddr >= (unsigned long)high_memory);
  98         }
  99 #endif
 100
 101         pagefault_enable();
 102 }
 103 EXPORT_SYMBOL(__kunmap_atomic);
 104
 105 struct page *kmap_atomic_to_page(void *ptr)
 106 {
 107         unsigned long idx, vaddr = (unsigned long)ptr;
 108         pte_t *pte;
 109
 110         if (vaddr < FIXADDR_START)
 111                 return virt_to_page(ptr);
 112
 113         idx = virt_to_fix(vaddr);
 114         pte = kmap_pte - (idx - FIX_KMAP_BEGIN);
 115         return pte_page(*pte);
 116 }
 117 EXPORT_SYMBOL(kmap_atomic_to_page);
 118
 119 void clear_highpage(struct page *page)
 120 {
 121         void *kaddr;
 122
 123         if (likely(xen_feature(XENFEAT_highmem_assist))
 124             && PageHighMem(page)) {
 125                 struct mmuext_op meo;
 126
 127                 meo.cmd = MMUEXT_CLEAR_PAGE;
 128                 meo.arg1.mfn = pfn_to_mfn(page_to_pfn(page));
 129                 if (HYPERVISOR_mmuext_op(&meo, 1, NULL, DOMID_SELF) == 0)
 130                         return;
 131         }
 132
 133         kaddr = kmap_atomic(page);
 134         clear_page(kaddr);
 135         kunmap_atomic(kaddr);
 136 }
 137 EXPORT_SYMBOL(clear_highpage);
 138
 139 void copy_highpage(struct page *to, struct page *from)
 140 {
 141         void *vfrom, *vto;
 142
 143         if (likely(xen_feature(XENFEAT_highmem_assist))
 144             && (PageHighMem(from) || PageHighMem(to))) {
 145                 unsigned long from_pfn = page_to_pfn(from);
 146                 unsigned long to_pfn = page_to_pfn(to);
 147                 struct mmuext_op meo;
 148
 149                 meo.cmd = MMUEXT_COPY_PAGE;
 150                 meo.arg1.mfn = pfn_to_mfn(to_pfn);
 151                 meo.arg2.src_mfn = pfn_to_mfn(from_pfn);
 152                 if (mfn_to_pfn(meo.arg2.src_mfn) == from_pfn
 153                     && mfn_to_pfn(meo.arg1.mfn) == to_pfn
 154                     && HYPERVISOR_mmuext_op(&meo, 1, NULL, DOMID_SELF) == 0)
 155                         return;
 156         }
 157
 158         vfrom = kmap_atomic(from);
 159         vto = kmap_atomic(to);
 160         copy_page(vto, vfrom);
 161         kunmap_atomic(vfrom);
 162         kunmap_atomic(vto);
 163 }
 164 EXPORT_SYMBOL(copy_highpage);
 165
 166 void __init set_highmem_pages_init(void)
 167 {
 168         struct zone *zone;
 169         int nid;
 170
 171         for_each_zone(zone) {
 172                 unsigned long zone_start_pfn, zone_end_pfn;
 173
 174                 if (!is_highmem(zone))
 175                         continue;
 176
 177                 zone_start_pfn = zone->zone_start_pfn;
 178                 zone_end_pfn = zone_start_pfn + zone->spanned_pages;
 179
 180                 nid = zone_to_nid(zone);
 181                 printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
 182                                 zone->name, nid, zone_start_pfn, zone_end_pfn);
 183
 184                 add_highpages_with_active_regions(nid, zone_start_pfn,
 185                                  zone_end_pfn);
 186
 187                 /* XEN: init high-mem pages outside initial allocation. */
 188                 if (zone_start_pfn < xen_start_info->nr_pages)
 189                         zone_start_pfn = xen_start_info->nr_pages;
 190                 for (; zone_start_pfn < zone_end_pfn; zone_start_pfn++) {
 191                         ClearPageReserved(pfn_to_page(zone_start_pfn));
 192                         init_page_count(pfn_to_page(zone_start_pfn));
 193                 }
 194         }
 195         totalram_pages += totalhigh_pages;
 196 }