common/kallsyms.c

   1 #include <common.h>
   2 #include <init.h>
   3 #include <kallsyms.h>
   4
   5 /* These will be re-linked against their real values during the second link stage */
   6 extern const unsigned long kallsyms_addresses[] __attribute__((weak));
   7 extern const unsigned long kallsyms_num_syms __attribute__((weak));
   8 extern const u8 kallsyms_names[] __attribute__((weak));
   9
  10 extern const u8 kallsyms_token_table[] __attribute__((weak));
  11 extern const u16 kallsyms_token_index[] __attribute__((weak));
  12
  13 extern const unsigned long kallsyms_markers[] __attribute__((weak));
  14
  15 /* expand a compressed symbol data into the resulting uncompressed string,
  16    given the offset to where the symbol is in the compressed stream */
  17 static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
  18 {
  19         int len, skipped_first = 0;
  20         const u8 *tptr, *data;
  21
  22         /* get the compressed symbol length from the first symbol byte */
  23         data = &kallsyms_names[off];
  24         len = *data;
  25         data++;
  26
  27         /* update the offset to return the offset for the next symbol on
  28          * the compressed stream */
  29         off += len + 1;
  30
  31         /* for every byte on the compressed symbol data, copy the table
  32            entry for that byte */
  33         while(len) {
  34                 tptr = &kallsyms_token_table[ kallsyms_token_index[*data] ];
  35                 data++;
  36                 len--;
  37
  38                 while (*tptr) {
  39                         if(skipped_first) {
  40                                 *result = *tptr;
  41                                 result++;
  42                         } else
  43                                 skipped_first = 1;
  44                         tptr++;
  45                 }
  46         }
  47
  48         *result = '\0';
  49
  50         /* return to offset to the next symbol */
  51         return off;
  52 }
  53
  54 /* Lookup the address for this symbol. Returns 0 if not found. */
  55 unsigned long kallsyms_lookup_name(const char *name)
  56 {
  57         char namebuf[KSYM_NAME_LEN];
  58         unsigned long i;
  59         unsigned int off;
  60
  61         for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
  62                 off = kallsyms_expand_symbol(off, namebuf);
  63
  64                 if (strcmp(namebuf, name) == 0)
  65                         return kallsyms_addresses[i];
  66         }
  67 //      return module_kallsyms_lookup_name(name);
  68         return 0;
  69 }