arch/x86/mm/highmem_32.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/highmem.h>
   3 #include <linux/export.h>
   4 #include <linux/swap.h> /* for totalram_pages */
   5 #include <linux/memblock.h>
   6
   7 void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
   8 {
   9         unsigned long vaddr;
  10         int idx, type;
  11
  12         type = kmap_atomic_idx_push();
  13         idx = type + KM_TYPE_NR*smp_processor_id();
  14         vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
  15         BUG_ON(!pte_none(*(kmap_pte-idx)));
  16         set_pte(kmap_pte-idx, mk_pte(page, prot));
  17         arch_flush_lazy_mmu_mode();
  18
  19         return (void *)vaddr;
  20 }
  21 EXPORT_SYMBOL(kmap_atomic_high_prot);
  22
  23 /*
  24  * This is the same as kmap_atomic() but can map memory that doesn't
  25  * have a struct page associated with it.
  26  */
  27 void *kmap_atomic_pfn(unsigned long pfn)
  28 {
  29         return kmap_atomic_prot_pfn(pfn, kmap_prot);
  30 }
  31 EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
  32
  33 void kunmap_atomic_high(void *kvaddr)
  34 {
  35         unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
  36
  37         if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
  38             vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
  39                 int idx, type;
  40
  41                 type = kmap_atomic_idx();
  42                 idx = type + KM_TYPE_NR * smp_processor_id();
  43
  44 #ifdef CONFIG_DEBUG_HIGHMEM
  45                 WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
  46 #endif
  47                 /*
  48                  * Force other mappings to Oops if they'll try to access this
  49                  * pte without first remap it.  Keeping stale mappings around
  50                  * is a bad idea also, in case the page changes cacheability
  51                  * attributes or becomes a protected page in a hypervisor.
  52                  */
  53                 kpte_clear_flush(kmap_pte-idx, vaddr);
  54                 kmap_atomic_idx_pop();
  55                 arch_flush_lazy_mmu_mode();
  56         }
  57 #ifdef CONFIG_DEBUG_HIGHMEM
  58         else {
  59                 BUG_ON(vaddr < PAGE_OFFSET);
  60                 BUG_ON(vaddr >= (unsigned long)high_memory);
  61         }
  62 #endif
  63 }
  64 EXPORT_SYMBOL(kunmap_atomic_high);
  65
  66 void __init set_highmem_pages_init(void)
  67 {
  68         struct zone *zone;
  69         int nid;
  70
  71         /*
  72          * Explicitly reset zone->managed_pages because set_highmem_pages_init()
  73          * is invoked before memblock_free_all()
  74          */
  75         reset_all_zones_managed_pages();
  76         for_each_zone(zone) {
  77                 unsigned long zone_start_pfn, zone_end_pfn;
  78
  79                 if (!is_highmem(zone))
  80                         continue;
  81
  82                 zone_start_pfn = zone->zone_start_pfn;
  83                 zone_end_pfn = zone_start_pfn + zone->spanned_pages;
  84
  85                 nid = zone_to_nid(zone);
  86                 printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n",
  87                                 zone->name, nid, zone_start_pfn, zone_end_pfn);
  88
  89                 add_highpages_with_active_regions(nid, zone_start_pfn,
  90                                  zone_end_pfn);
  91         }
  92 }