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