scripts/kallsyms.c

   1 /* Generate assembler source containing symbol information
   2  *
   3  * Copyright 2002       by Kai Germaschewski
   4  *
   5  * This software may be used and distributed according to the terms
   6  * of the GNU General Public License, incorporated herein by reference.
   7  *
   8  * Usage: nm -n vmlinux | scripts/kallsyms [--all-symbols] > symbols.S
   9  */
  10
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include <ctype.h>
  15
  16 struct sym_entry {
  17         unsigned long long addr;
  18         char type;
  19         char *sym;
  20 };
  21
  22
  23 static struct sym_entry *table;
  24 static int size, cnt;
  25 static unsigned long long _stext, _etext, _sinittext, _einittext;
  26 static int all_symbols = 0;
  27
  28 static void
  29 usage(void)
  30 {
  31         fprintf(stderr, "Usage: kallsyms [--all-symbols] < in.map > out.S\n");
  32         exit(1);
  33 }
  34
  35 static int
  36 read_symbol(FILE *in, struct sym_entry *s)
  37 {
  38         char str[500];
  39         int rc;
  40
  41         rc = fscanf(in, "%llx %c %499s\n", &s->addr, &s->type, str);
  42         if (rc != 3) {
  43                 if (rc != EOF) {
  44                         /* skip line */
  45                         fgets(str, 500, in);
  46                 }
  47                 return -1;
  48         }
  49
  50         /* Ignore most absolute/undefined (?) symbols. */
  51         if (strcmp(str, "_stext") == 0)
  52                 _stext = s->addr;
  53         else if (strcmp(str, "_etext") == 0)
  54                 _etext = s->addr;
  55         else if (strcmp(str, "_sinittext") == 0)
  56                 _sinittext = s->addr;
  57         else if (strcmp(str, "_einittext") == 0)
  58                 _einittext = s->addr;
  59         else if (toupper(s->type) == 'A' || toupper(s->type) == 'U')
  60                 return -1;
  61
  62         s->sym = strdup(str);
  63         return 0;
  64 }
  65
  66 static int
  67 symbol_valid(struct sym_entry *s)
  68 {
  69         if (!all_symbols) {
  70                 if ((s->addr < _stext || s->addr > _etext)
  71                     && (s->addr < _sinittext || s->addr > _einittext))
  72                         return 0;
  73         }
  74
  75         /* Exclude symbols which vary between passes.  Passes 1 and 2 must have
  76          * identical symbol lists.  The kallsyms_* symbols below are only added
  77          * after pass 1, they would be included in pass 2 when --all-symbols is
  78          * specified so exclude them to get a stable symbol list.
  79          */
  80         if (strstr(s->sym, "_compiled.") ||
  81             strcmp(s->sym, "kallsyms_addresses") == 0 ||
  82             strcmp(s->sym, "kallsyms_num_syms") == 0 ||
  83             strcmp(s->sym, "kallsyms_names") == 0)
  84                 return 0;
  85
  86         /* Exclude linker generated symbols which vary between passes */
  87         if (strcmp(s->sym, "_SDA_BASE_") == 0 ||        /* ppc */
  88             strcmp(s->sym, "_SDA2_BASE_") == 0)         /* ppc */
  89                 return 0;
  90
  91         return 1;
  92 }
  93
  94 static void
  95 read_map(FILE *in)
  96 {
  97         while (!feof(in)) {
  98                 if (cnt >= size) {
  99                         size += 10000;
 100                         table = realloc(table, sizeof(*table) * size);
 101                         if (!table) {
 102                                 fprintf(stderr, "out of memory\n");
 103                                 exit (1);
 104                         }
 105                 }
 106                 if (read_symbol(in, &table[cnt]) == 0)
 107                         cnt++;
 108         }
 109 }
 110
 111 static void
 112 write_src(void)
 113 {
 114         int i, valid = 0;
 115         char *prev;
 116
 117         printf("#include <asm/types.h>\n");
 118         printf("#if BITS_PER_LONG == 64\n");
 119         printf("#define PTR .quad\n");
 120         printf("#define ALGN .align 8\n");
 121         printf("#else\n");
 122         printf("#define PTR .long\n");
 123         printf("#define ALGN .align 4\n");
 124         printf("#endif\n");
 125
 126         printf(".data\n");
 127
 128         printf(".globl kallsyms_addresses\n");
 129         printf("\tALGN\n");
 130         printf("kallsyms_addresses:\n");
 131         for (i = 0; i < cnt; i++) {
 132                 if (!symbol_valid(&table[i]))
 133                         continue;
 134
 135                 printf("\tPTR\t%#llx\n", table[i].addr);
 136                 valid++;
 137         }
 138         printf("\n");
 139
 140         printf(".globl kallsyms_num_syms\n");
 141         printf("\tALGN\n");
 142         printf("kallsyms_num_syms:\n");
 143         printf("\tPTR\t%d\n", valid);
 144         printf("\n");
 145
 146         printf(".globl kallsyms_names\n");
 147         printf("\tALGN\n");
 148         printf("kallsyms_names:\n");
 149         prev = "";
 150         for (i = 0; i < cnt; i++) {
 151                 int k;
 152
 153                 if (!symbol_valid(&table[i]))
 154                         continue;
 155
 156                 for (k = 0; table[i].sym[k] && table[i].sym[k] == prev[k]; ++k)
 157                         ;
 158
 159                 printf("\t.byte 0x%02x\n\t.asciz\t\"%s\"\n", k, table[i].sym + k);
 160                 prev = table[i].sym;
 161         }
 162         printf("\n");
 163 }
 164
 165 int
 166 main(int argc, char **argv)
 167 {
 168         if (argc == 2 && strcmp(argv[1], "--all-symbols") == 0)
 169                 all_symbols = 1;
 170         else if (argc != 1)
 171                 usage();
 172
 173         read_map(stdin);
 174         write_src();
 175
 176         return 0;
 177 }
 178