arch/sparc64/mm/extable.c

   1 /*
   2  * linux/arch/sparc64/mm/extable.c
   3  */
   4
   5 #include <linux/config.h>
   6 #include <linux/module.h>
   7 #include <asm/uaccess.h>
   8
   9 extern const struct exception_table_entry __start___ex_table[];
  10 extern const struct exception_table_entry __stop___ex_table[];
  11
  12 void sort_extable(struct exception_table_entry *start,
  13                   struct exception_table_entry *finish)
  14 {
  15 }
  16
  17 /* Caller knows they are in a range if ret->fixup == 0 */
  18 const struct exception_table_entry *
  19 search_extable(const struct exception_table_entry *start,
  20                const struct exception_table_entry *last,
  21                unsigned long value)
  22 {
  23         const struct exception_table_entry *walk;
  24
  25         /* Single insn entries are encoded as:
  26          *      word 1: insn address
  27          *      word 2: fixup code address
  28          *
  29          * Range entries are encoded as:
  30          *      word 1: first insn address
  31          *      word 2: 0
  32          *      word 3: last insn address + 4 bytes
  33          *      word 4: fixup code address
  34          *
  35          * See asm/uaccess.h for more details.
  36          */
  37
  38         /* 1. Try to find an exact match. */
  39         for (walk = start; walk <= last; walk++) {
  40                 if (walk->fixup == 0) {
  41                         /* A range entry, skip both parts. */
  42                         walk++;
  43                         continue;
  44                 }
  45
  46                 if (walk->insn == value)
  47                         return walk;
  48         }
  49
  50         /* 2. Try to find a range match. */
  51         for (walk = start; walk <= (last - 1); walk++) {
  52                 if (walk->fixup)
  53                         continue;
  54
  55                 if (walk[0].insn <= value && walk[1].insn > value)
  56                         return walk;
  57
  58                 walk++;
  59         }
  60
  61         return NULL;
  62 }
  63
  64 /* Special extable search, which handles ranges.  Returns fixup */
  65 unsigned long search_extables_range(unsigned long addr, unsigned long *g2)
  66 {
  67         const struct exception_table_entry *entry;
  68
  69         entry = search_exception_tables(addr);
  70         if (!entry)
  71                 return 0;
  72
  73         /* Inside range?  Fix g2 and return correct fixup */
  74         if (!entry->fixup) {
  75                 *g2 = (addr - entry->insn) / 4;
  76                 return (entry + 1)->fixup;
  77         }
  78
  79         return entry->fixup;
  80 }