arch/sparc/mm/extable.c

   1 /*
   2  * linux/arch/sparc/mm/extable.c
   3  */
   4
   5 #include <linux/module.h>
   6 #include <asm/uaccess.h>
   7
   8 void sort_extable(struct exception_table_entry *start,
   9                   struct exception_table_entry *finish)
  10 {
  11 }
  12
  13 /* Caller knows they are in a range if ret->fixup == 0 */
  14 const struct exception_table_entry *
  15 search_extable(const struct exception_table_entry *start,
  16                const struct exception_table_entry *last,
  17                unsigned long value)
  18 {
  19         const struct exception_table_entry *walk;
  20
  21         /* Single insn entries are encoded as:
  22          *      word 1: insn address
  23          *      word 2: fixup code address
  24          *
  25          * Range entries are encoded as:
  26          *      word 1: first insn address
  27          *      word 2: 0
  28          *      word 3: last insn address + 4 bytes
  29          *      word 4: fixup code address
  30          *
  31          * See asm/uaccess.h for more details.
  32          */
  33
  34         /* 1. Try to find an exact match. */
  35         for (walk = start; walk <= last; walk++) {
  36                 if (walk->fixup == 0) {
  37                         /* A range entry, skip both parts. */
  38                         walk++;
  39                         continue;
  40                 }
  41
  42                 if (walk->insn == value)
  43                         return walk;
  44         }
  45
  46         /* 2. Try to find a range match. */
  47         for (walk = start; walk <= (last - 1); walk++) {
  48                 if (walk->fixup)
  49                         continue;
  50
  51                 if (walk[0].insn <= value && walk[1].insn > value)
  52                         return walk;
  53
  54                 walk++;
  55         }
  56
  57         return NULL;
  58 }
  59
  60 /* Special extable search, which handles ranges.  Returns fixup */
  61 unsigned long search_extables_range(unsigned long addr, unsigned long *g2)
  62 {
  63         const struct exception_table_entry *entry;
  64
  65         entry = search_exception_tables(addr);
  66         if (!entry)
  67                 return 0;
  68
  69         /* Inside range?  Fix g2 and return correct fixup */
  70         if (!entry->fixup) {
  71                 *g2 = (addr - entry->insn) / 4;
  72                 return (entry + 1)->fixup;
  73         }
  74
  75         return entry->fixup;
  76 }