arch/sparc/mm/extable.c

   1 /*
   2  * linux/arch/sparc/mm/extable.c
   3  */
   4
   5 #include <linux/config.h>
   6 #include <linux/module.h>
   7 #include <asm/uaccess.h>
   8
   9 void sort_extable(struct exception_table_entry *start,
  10                   struct exception_table_entry *finish)
  11 {
  12 }
  13
  14 /* Caller knows they are in a range if ret->fixup == 0 */
  15 const struct exception_table_entry *
  16 search_extable(const struct exception_table_entry *start,
  17                const struct exception_table_entry *last,
  18                unsigned long value)
  19 {
  20         const struct exception_table_entry *walk;
  21
  22         /* Single insn entries are encoded as:
  23          *      word 1: insn address
  24          *      word 2: fixup code address
  25          *
  26          * Range entries are encoded as:
  27          *      word 1: first insn address
  28          *      word 2: 0
  29          *      word 3: last insn address + 4 bytes
  30          *      word 4: fixup code address
  31          *
  32          * See asm/uaccess.h for more details.
  33          */
  34
  35         /* 1. Try to find an exact match. */
  36         for (walk = start; walk <= last; walk++) {
  37                 if (walk->fixup == 0) {
  38                         /* A range entry, skip both parts. */
  39                         walk++;
  40                         continue;
  41                 }
  42
  43                 if (walk->insn == value)
  44                         return walk;
  45         }
  46
  47         /* 2. Try to find a range match. */
  48         for (walk = start; walk <= (last - 1); walk++) {
  49                 if (walk->fixup)
  50                         continue;
  51
  52                 if (walk[0].insn <= value && walk[1].insn > value)
  53                         return walk;
  54
  55                 walk++;
  56         }
  57
  58         return NULL;
  59 }
  60
  61 /* Special extable search, which handles ranges.  Returns fixup */
  62 unsigned long search_extables_range(unsigned long addr, unsigned long *g2)
  63 {
  64         const struct exception_table_entry *entry;
  65
  66         entry = search_exception_tables(addr);
  67         if (!entry)
  68                 return 0;
  69
  70         /* Inside range?  Fix g2 and return correct fixup */
  71         if (!entry->fixup) {
  72                 *g2 = (addr - entry->insn) / 4;
  73                 return (entry + 1)->fixup;
  74         }
  75
  76         return entry->fixup;
  77 }