arch/arm/xen/p2m.c

   1 #include <linux/bootmem.h>
   2 #include <linux/gfp.h>
   3 #include <linux/export.h>
   4 #include <linux/rwlock.h>
   5 #include <linux/slab.h>
   6 #include <linux/types.h>
   7 #include <linux/dma-mapping.h>
   8 #include <linux/vmalloc.h>
   9 #include <linux/swiotlb.h>
  10
  11 #include <xen/xen.h>
  12 #include <xen/interface/memory.h>
  13 #include <xen/swiotlb-xen.h>
  14
  15 #include <asm/cacheflush.h>
  16 #include <asm/xen/page.h>
  17 #include <asm/xen/hypercall.h>
  18 #include <asm/xen/interface.h>
  19
  20 struct xen_p2m_entry {
  21         unsigned long pfn;
  22         unsigned long mfn;
  23         unsigned long nr_pages;
  24         struct rb_node rbnode_mach;
  25         struct rb_node rbnode_phys;
  26 };
  27
  28 rwlock_t p2m_lock;
  29 struct rb_root phys_to_mach = RB_ROOT;
  30 static struct rb_root mach_to_phys = RB_ROOT;
  31
  32 static int xen_add_phys_to_mach_entry(struct xen_p2m_entry *new)
  33 {
  34         struct rb_node **link = &phys_to_mach.rb_node;
  35         struct rb_node *parent = NULL;
  36         struct xen_p2m_entry *entry;
  37         int rc = 0;
  38
  39         while (*link) {
  40                 parent = *link;
  41                 entry = rb_entry(parent, struct xen_p2m_entry, rbnode_phys);
  42
  43                 if (new->mfn == entry->mfn)
  44                         goto err_out;
  45                 if (new->pfn == entry->pfn)
  46                         goto err_out;
  47
  48                 if (new->pfn < entry->pfn)
  49                         link = &(*link)->rb_left;
  50                 else
  51                         link = &(*link)->rb_right;
  52         }
  53         rb_link_node(&new->rbnode_phys, parent, link);
  54         rb_insert_color(&new->rbnode_phys, &phys_to_mach);
  55         goto out;
  56
  57 err_out:
  58         rc = -EINVAL;
  59         pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
  60                         __func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
  61 out:
  62         return rc;
  63 }
  64
  65 unsigned long __pfn_to_mfn(unsigned long pfn)
  66 {
  67         struct rb_node *n = phys_to_mach.rb_node;
  68         struct xen_p2m_entry *entry;
  69         unsigned long irqflags;
  70
  71         read_lock_irqsave(&p2m_lock, irqflags);
  72         while (n) {
  73                 entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
  74                 if (entry->pfn <= pfn &&
  75                                 entry->pfn + entry->nr_pages > pfn) {
  76                         read_unlock_irqrestore(&p2m_lock, irqflags);
  77                         return entry->mfn + (pfn - entry->pfn);
  78                 }
  79                 if (pfn < entry->pfn)
  80                         n = n->rb_left;
  81                 else
  82                         n = n->rb_right;
  83         }
  84         read_unlock_irqrestore(&p2m_lock, irqflags);
  85
  86         return INVALID_P2M_ENTRY;
  87 }
  88 EXPORT_SYMBOL_GPL(__pfn_to_mfn);
  89
  90 static int xen_add_mach_to_phys_entry(struct xen_p2m_entry *new)
  91 {
  92         struct rb_node **link = &mach_to_phys.rb_node;
  93         struct rb_node *parent = NULL;
  94         struct xen_p2m_entry *entry;
  95         int rc = 0;
  96
  97         while (*link) {
  98                 parent = *link;
  99                 entry = rb_entry(parent, struct xen_p2m_entry, rbnode_mach);
 100
 101                 if (new->mfn == entry->mfn)
 102                         goto err_out;
 103                 if (new->pfn == entry->pfn)
 104                         goto err_out;
 105
 106                 if (new->mfn < entry->mfn)
 107                         link = &(*link)->rb_left;
 108                 else
 109                         link = &(*link)->rb_right;
 110         }
 111         rb_link_node(&new->rbnode_mach, parent, link);
 112         rb_insert_color(&new->rbnode_mach, &mach_to_phys);
 113         goto out;
 114
 115 err_out:
 116         rc = -EINVAL;
 117         pr_warn("%s: cannot add pfn=%pa -> mfn=%pa: pfn=%pa -> mfn=%pa already exists\n",
 118                         __func__, &new->pfn, &new->mfn, &entry->pfn, &entry->mfn);
 119 out:
 120         return rc;
 121 }
 122
 123 unsigned long __mfn_to_pfn(unsigned long mfn)
 124 {
 125         struct rb_node *n = mach_to_phys.rb_node;
 126         struct xen_p2m_entry *entry;
 127         unsigned long irqflags;
 128
 129         read_lock_irqsave(&p2m_lock, irqflags);
 130         while (n) {
 131                 entry = rb_entry(n, struct xen_p2m_entry, rbnode_mach);
 132                 if (entry->mfn <= mfn &&
 133                                 entry->mfn + entry->nr_pages > mfn) {
 134                         read_unlock_irqrestore(&p2m_lock, irqflags);
 135                         return entry->pfn + (mfn - entry->mfn);
 136                 }
 137                 if (mfn < entry->mfn)
 138                         n = n->rb_left;
 139                 else
 140                         n = n->rb_right;
 141         }
 142         read_unlock_irqrestore(&p2m_lock, irqflags);
 143
 144         return INVALID_P2M_ENTRY;
 145 }
 146 EXPORT_SYMBOL_GPL(__mfn_to_pfn);
 147
 148 bool __set_phys_to_machine_multi(unsigned long pfn,
 149                 unsigned long mfn, unsigned long nr_pages)
 150 {
 151         int rc;
 152         unsigned long irqflags;
 153         struct xen_p2m_entry *p2m_entry;
 154         struct rb_node *n = phys_to_mach.rb_node;
 155
 156         if (mfn == INVALID_P2M_ENTRY) {
 157                 write_lock_irqsave(&p2m_lock, irqflags);
 158                 while (n) {
 159                         p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 160                         if (p2m_entry->pfn <= pfn &&
 161                                         p2m_entry->pfn + p2m_entry->nr_pages > pfn) {
 162                                 rb_erase(&p2m_entry->rbnode_mach, &mach_to_phys);
 163                                 rb_erase(&p2m_entry->rbnode_phys, &phys_to_mach);
 164                                 write_unlock_irqrestore(&p2m_lock, irqflags);
 165                                 kfree(p2m_entry);
 166                                 return true;
 167                         }
 168                         if (pfn < p2m_entry->pfn)
 169                                 n = n->rb_left;
 170                         else
 171                                 n = n->rb_right;
 172                 }
 173                 write_unlock_irqrestore(&p2m_lock, irqflags);
 174                 return true;
 175         }
 176
 177         p2m_entry = kzalloc(sizeof(struct xen_p2m_entry), GFP_NOWAIT);
 178         if (!p2m_entry) {
 179                 pr_warn("cannot allocate xen_p2m_entry\n");
 180                 return false;
 181         }
 182         p2m_entry->pfn = pfn;
 183         p2m_entry->nr_pages = nr_pages;
 184         p2m_entry->mfn = mfn;
 185
 186         write_lock_irqsave(&p2m_lock, irqflags);
 187         if ((rc = xen_add_phys_to_mach_entry(p2m_entry) < 0) ||
 188                 (rc = xen_add_mach_to_phys_entry(p2m_entry) < 0)) {
 189                 write_unlock_irqrestore(&p2m_lock, irqflags);
 190                 return false;
 191         }
 192         write_unlock_irqrestore(&p2m_lock, irqflags);
 193         return true;
 194 }
 195 EXPORT_SYMBOL_GPL(__set_phys_to_machine_multi);
 196
 197 bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 198 {
 199         return __set_phys_to_machine_multi(pfn, mfn, 1);
 200 }
 201 EXPORT_SYMBOL_GPL(__set_phys_to_machine);
 202
 203 int p2m_init(void)
 204 {
 205         rwlock_init(&p2m_lock);
 206         return 0;
 207 }
 208 arch_initcall(p2m_init);