arch/x86/kernel/pci-iommu_table.c

   1 #include <linux/dma-mapping.h>
   2 #include <asm/iommu_table.h>
   3 #include <linux/string.h>
   4 #include <linux/kallsyms.h>
   5
   6
   7 #define DEBUG 1
   8
   9 static struct iommu_table_entry * __init
  10 find_dependents_of(struct iommu_table_entry *start,
  11                    struct iommu_table_entry *finish,
  12                    struct iommu_table_entry *q)
  13 {
  14         struct iommu_table_entry *p;
  15
  16         if (!q)
  17                 return NULL;
  18
  19         for (p = start; p < finish; p++)
  20                 if (p->detect == q->depend)
  21                         return p;
  22
  23         return NULL;
  24 }
  25
  26
  27 void __init sort_iommu_table(struct iommu_table_entry *start,
  28                              struct iommu_table_entry *finish) {
  29
  30         struct iommu_table_entry *p, *q, tmp;
  31
  32         for (p = start; p < finish; p++) {
  33 again:
  34                 q = find_dependents_of(start, finish, p);
  35                 /* We are bit sneaky here. We use the memory address to figure
  36                  * out if the node we depend on is past our point, if so, swap.
  37                  */
  38                 if (q > p) {
  39                         tmp = *p;
  40                         memmove(p, q, sizeof(*p));
  41                         *q = tmp;
  42                         goto again;
  43                 }
  44         }
  45
  46 }
  47
  48 #ifdef DEBUG
  49 void __init check_iommu_entries(struct iommu_table_entry *start,
  50                                 struct iommu_table_entry *finish)
  51 {
  52         struct iommu_table_entry *p, *q, *x;
  53
  54         /* Simple cyclic dependency checker. */
  55         for (p = start; p < finish; p++) {
  56                 q = find_dependents_of(start, finish, p);
  57                 x = find_dependents_of(start, finish, q);
  58                 if (p == x) {
  59                         printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %pS depends on %pS and vice-versa. BREAKING IT.\n",
  60                                p->detect, q->detect);
  61                         /* Heavy handed way..*/
  62                         x->depend = 0;
  63                 }
  64         }
  65
  66         for (p = start; p < finish; p++) {
  67                 q = find_dependents_of(p, finish, p);
  68                 if (q && q > p) {
  69                         printk(KERN_ERR "EXECUTION ORDER INVALID! %pS should be called before %pS!\n",
  70                                p->detect, q->detect);
  71                 }
  72         }
  73 }
  74 #else
  75 inline void check_iommu_entries(struct iommu_table_entry *start,
  76                                        struct iommu_table_entry *finish)
  77 {
  78 }
  79 #endif