664 lines
15 KiB
C
664 lines
15 KiB
C
/* Generate assembler source containing symbol information
|
|
*
|
|
* Copyright 2002 by Kai Germaschewski
|
|
*
|
|
* This software may be used and distributed according to the terms
|
|
* of the GNU General Public License, incorporated herein by reference.
|
|
*
|
|
* Usage: nm -n vmlinux | scripts/kallsyms [--all-symbols] > symbols.S
|
|
*
|
|
* Table compression uses all the unused char codes on the symbols and
|
|
* maps these to the most used substrings (tokens). For instance, it might
|
|
* map char code 0xF7 to represent "write_" and then in every symbol where
|
|
* "write_" appears it can be replaced by 0xF7, saving 5 bytes.
|
|
* The used codes themselves are also placed in the table so that the
|
|
* decompresion can work without "special cases".
|
|
* Applied to kernel symbols, this usually produces a compression ratio
|
|
* of about 50%.
|
|
*
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <ctype.h>
|
|
|
|
#ifndef ARRAY_SIZE
|
|
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
|
|
#endif
|
|
|
|
#define KSYM_NAME_LEN 128
|
|
|
|
struct sym_entry {
|
|
unsigned long long addr;
|
|
unsigned int len;
|
|
unsigned int start_pos;
|
|
unsigned char *sym;
|
|
};
|
|
|
|
struct text_range {
|
|
const char *stext, *etext;
|
|
unsigned long long start, end;
|
|
};
|
|
|
|
static unsigned long long _text;
|
|
static struct text_range text_ranges[] = {
|
|
{ "_stext", "_etext" },
|
|
{ "_sinittext", "_einittext" },
|
|
{ "_stext_l1", "_etext_l1" }, /* Blackfin on-chip L1 inst SRAM */
|
|
{ "_stext_l2", "_etext_l2" }, /* Blackfin on-chip L2 SRAM */
|
|
};
|
|
#define text_range_text (&text_ranges[0])
|
|
#define text_range_inittext (&text_ranges[1])
|
|
|
|
static struct sym_entry *table;
|
|
static unsigned int table_size, table_cnt;
|
|
static int all_symbols = 0;
|
|
static char symbol_prefix_char = '\0';
|
|
|
|
int token_profit[0x10000];
|
|
|
|
/* the table that holds the result of the compression */
|
|
unsigned char best_table[256][2];
|
|
unsigned char best_table_len[256];
|
|
|
|
|
|
static void usage(void)
|
|
{
|
|
fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n");
|
|
exit(1);
|
|
}
|
|
|
|
/*
|
|
* This ignores the intensely annoying "mapping symbols" found
|
|
* in ARM ELF files: $a, $t and $d.
|
|
*/
|
|
static inline int is_arm_mapping_symbol(const char *str)
|
|
{
|
|
return str[0] == '$' && strchr("atd", str[1])
|
|
&& (str[2] == '\0' || str[2] == '.');
|
|
}
|
|
|
|
static int read_symbol_tr(const char *sym, unsigned long long addr)
|
|
{
|
|
size_t i;
|
|
struct text_range *tr;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(text_ranges); ++i) {
|
|
tr = &text_ranges[i];
|
|
|
|
if (strcmp(sym, tr->stext) == 0) {
|
|
tr->start = addr;
|
|
return 0;
|
|
} else if (strcmp(sym, tr->etext) == 0) {
|
|
tr->end = addr;
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int read_symbol(FILE *in, struct sym_entry *s)
|
|
{
|
|
char str[500];
|
|
char *sym, stype;
|
|
int rc;
|
|
|
|
rc = fscanf(in, "%llx %c %499s\n", &s->addr, &stype, str);
|
|
if (rc != 3) {
|
|
if (rc != EOF) {
|
|
/* skip line. sym is used as dummy to
|
|
* shut of "warn_unused_result" warning.
|
|
*/
|
|
sym = fgets(str, 500, in);
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
sym = str;
|
|
/* skip prefix char */
|
|
if (symbol_prefix_char && str[0] == symbol_prefix_char)
|
|
sym++;
|
|
|
|
/* Ignore most absolute/undefined (?) symbols. */
|
|
if (strcmp(sym, "_text") == 0)
|
|
_text = s->addr;
|
|
else if (read_symbol_tr(sym, s->addr) == 0)
|
|
/* nothing to do */;
|
|
else if (toupper(stype) == 'A')
|
|
{
|
|
/* Keep these useful absolute symbols */
|
|
if (strcmp(sym, "__kernel_syscall_via_break") &&
|
|
strcmp(sym, "__kernel_syscall_via_epc") &&
|
|
strcmp(sym, "__kernel_sigtramp") &&
|
|
strcmp(sym, "__gp"))
|
|
return -1;
|
|
|
|
}
|
|
else if (toupper(stype) == 'U' ||
|
|
is_arm_mapping_symbol(sym))
|
|
return -1;
|
|
/* exclude also MIPS ELF local symbols ($L123 instead of .L123) */
|
|
else if (str[0] == '$')
|
|
return -1;
|
|
/* exclude debugging symbols */
|
|
else if (stype == 'N')
|
|
return -1;
|
|
|
|
/* include the type field in the symbol name, so that it gets
|
|
* compressed together */
|
|
s->len = strlen(str) + 1;
|
|
s->sym = malloc(s->len + 1);
|
|
if (!s->sym) {
|
|
fprintf(stderr, "kallsyms failure: "
|
|
"unable to allocate required amount of memory\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
strcpy((char *)s->sym + 1, str);
|
|
s->sym[0] = stype;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int symbol_valid_tr(struct sym_entry *s)
|
|
{
|
|
size_t i;
|
|
struct text_range *tr;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(text_ranges); ++i) {
|
|
tr = &text_ranges[i];
|
|
|
|
if (s->addr >= tr->start && s->addr <= tr->end)
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int symbol_valid(struct sym_entry *s)
|
|
{
|
|
/* Symbols which vary between passes. Passes 1 and 2 must have
|
|
* identical symbol lists. The kallsyms_* symbols below are only added
|
|
* after pass 1, they would be included in pass 2 when --all-symbols is
|
|
* specified so exclude them to get a stable symbol list.
|
|
*/
|
|
static char *special_symbols[] = {
|
|
"kallsyms_addresses",
|
|
"kallsyms_num_syms",
|
|
"kallsyms_names",
|
|
"kallsyms_markers",
|
|
"kallsyms_token_table",
|
|
"kallsyms_token_index",
|
|
|
|
/* Exclude linker generated symbols which vary between passes */
|
|
"_SDA_BASE_", /* ppc */
|
|
"_SDA2_BASE_", /* ppc */
|
|
NULL };
|
|
int i;
|
|
int offset = 1;
|
|
|
|
/* skip prefix char */
|
|
if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char)
|
|
offset++;
|
|
|
|
/* if --all-symbols is not specified, then symbols outside the text
|
|
* and inittext sections are discarded */
|
|
if (!all_symbols) {
|
|
if (symbol_valid_tr(s) == 0)
|
|
return 0;
|
|
/* Corner case. Discard any symbols with the same value as
|
|
* _etext _einittext; they can move between pass 1 and 2 when
|
|
* the kallsyms data are added. If these symbols move then
|
|
* they may get dropped in pass 2, which breaks the kallsyms
|
|
* rules.
|
|
*/
|
|
if ((s->addr == text_range_text->end &&
|
|
strcmp((char *)s->sym + offset, text_range_text->etext)) ||
|
|
(s->addr == text_range_inittext->end &&
|
|
strcmp((char *)s->sym + offset, text_range_inittext->etext)))
|
|
return 0;
|
|
}
|
|
|
|
/* Exclude symbols which vary between passes. */
|
|
if (strstr((char *)s->sym + offset, "_compiled."))
|
|
return 0;
|
|
|
|
for (i = 0; special_symbols[i]; i++)
|
|
if( strcmp((char *)s->sym + offset, special_symbols[i]) == 0 )
|
|
return 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void read_map(FILE *in)
|
|
{
|
|
while (!feof(in)) {
|
|
if (table_cnt >= table_size) {
|
|
table_size += 10000;
|
|
table = realloc(table, sizeof(*table) * table_size);
|
|
if (!table) {
|
|
fprintf(stderr, "out of memory\n");
|
|
exit (1);
|
|
}
|
|
}
|
|
if (read_symbol(in, &table[table_cnt]) == 0) {
|
|
table[table_cnt].start_pos = table_cnt;
|
|
table_cnt++;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void output_label(char *label)
|
|
{
|
|
if (symbol_prefix_char)
|
|
printf(".globl %c%s\n", symbol_prefix_char, label);
|
|
else
|
|
printf(".globl %s\n", label);
|
|
printf("\tALGN\n");
|
|
if (symbol_prefix_char)
|
|
printf("%c%s:\n", symbol_prefix_char, label);
|
|
else
|
|
printf("%s:\n", label);
|
|
}
|
|
|
|
/* uncompress a compressed symbol. When this function is called, the best table
|
|
* might still be compressed itself, so the function needs to be recursive */
|
|
static int expand_symbol(unsigned char *data, int len, char *result)
|
|
{
|
|
int c, rlen, total=0;
|
|
|
|
while (len) {
|
|
c = *data;
|
|
/* if the table holds a single char that is the same as the one
|
|
* we are looking for, then end the search */
|
|
if (best_table[c][0]==c && best_table_len[c]==1) {
|
|
*result++ = c;
|
|
total++;
|
|
} else {
|
|
/* if not, recurse and expand */
|
|
rlen = expand_symbol(best_table[c], best_table_len[c], result);
|
|
total += rlen;
|
|
result += rlen;
|
|
}
|
|
data++;
|
|
len--;
|
|
}
|
|
*result=0;
|
|
|
|
return total;
|
|
}
|
|
|
|
static void write_src(void)
|
|
{
|
|
unsigned int i, k, off;
|
|
unsigned int best_idx[256];
|
|
unsigned int *markers;
|
|
char buf[KSYM_NAME_LEN];
|
|
|
|
printf("#include <asm/types.h>\n");
|
|
printf("#if BITS_PER_LONG == 64\n");
|
|
printf("#define PTR .quad\n");
|
|
printf("#define ALGN .align 8\n");
|
|
printf("#else\n");
|
|
printf("#define PTR .long\n");
|
|
printf("#define ALGN .align 4\n");
|
|
printf("#endif\n");
|
|
|
|
printf("\t.section .rodata, \"a\"\n");
|
|
|
|
/* Provide proper symbols relocatability by their '_text'
|
|
* relativeness. The symbol names cannot be used to construct
|
|
* normal symbol references as the list of symbols contains
|
|
* symbols that are declared static and are private to their
|
|
* .o files. This prevents .tmp_kallsyms.o or any other
|
|
* object from referencing them.
|
|
*/
|
|
output_label("kallsyms_addresses");
|
|
for (i = 0; i < table_cnt; i++) {
|
|
if (toupper(table[i].sym[0]) != 'A') {
|
|
if (_text <= table[i].addr)
|
|
printf("\tPTR\t_text + %#llx\n",
|
|
table[i].addr - _text);
|
|
else
|
|
printf("\tPTR\t_text - %#llx\n",
|
|
_text - table[i].addr);
|
|
} else {
|
|
printf("\tPTR\t%#llx\n", table[i].addr);
|
|
}
|
|
}
|
|
printf("\n");
|
|
|
|
output_label("kallsyms_num_syms");
|
|
printf("\tPTR\t%d\n", table_cnt);
|
|
printf("\n");
|
|
|
|
/* table of offset markers, that give the offset in the compressed stream
|
|
* every 256 symbols */
|
|
markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256));
|
|
if (!markers) {
|
|
fprintf(stderr, "kallsyms failure: "
|
|
"unable to allocate required memory\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
output_label("kallsyms_names");
|
|
off = 0;
|
|
for (i = 0; i < table_cnt; i++) {
|
|
if ((i & 0xFF) == 0)
|
|
markers[i >> 8] = off;
|
|
|
|
printf("\t.byte 0x%02x", table[i].len);
|
|
for (k = 0; k < table[i].len; k++)
|
|
printf(", 0x%02x", table[i].sym[k]);
|
|
printf("\n");
|
|
|
|
off += table[i].len + 1;
|
|
}
|
|
printf("\n");
|
|
|
|
output_label("kallsyms_markers");
|
|
for (i = 0; i < ((table_cnt + 255) >> 8); i++)
|
|
printf("\tPTR\t%d\n", markers[i]);
|
|
printf("\n");
|
|
|
|
free(markers);
|
|
|
|
output_label("kallsyms_token_table");
|
|
off = 0;
|
|
for (i = 0; i < 256; i++) {
|
|
best_idx[i] = off;
|
|
expand_symbol(best_table[i], best_table_len[i], buf);
|
|
printf("\t.asciz\t\"%s\"\n", buf);
|
|
off += strlen(buf) + 1;
|
|
}
|
|
printf("\n");
|
|
|
|
output_label("kallsyms_token_index");
|
|
for (i = 0; i < 256; i++)
|
|
printf("\t.short\t%d\n", best_idx[i]);
|
|
printf("\n");
|
|
}
|
|
|
|
|
|
/* table lookup compression functions */
|
|
|
|
/* count all the possible tokens in a symbol */
|
|
static void learn_symbol(unsigned char *symbol, int len)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < len - 1; i++)
|
|
token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++;
|
|
}
|
|
|
|
/* decrease the count for all the possible tokens in a symbol */
|
|
static void forget_symbol(unsigned char *symbol, int len)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < len - 1; i++)
|
|
token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
|
|
}
|
|
|
|
/* remove all the invalid symbols from the table and do the initial token count */
|
|
static void build_initial_tok_table(void)
|
|
{
|
|
unsigned int i, pos;
|
|
|
|
pos = 0;
|
|
for (i = 0; i < table_cnt; i++) {
|
|
if ( symbol_valid(&table[i]) ) {
|
|
if (pos != i)
|
|
table[pos] = table[i];
|
|
learn_symbol(table[pos].sym, table[pos].len);
|
|
pos++;
|
|
}
|
|
}
|
|
table_cnt = pos;
|
|
}
|
|
|
|
static void *find_token(unsigned char *str, int len, unsigned char *token)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < len - 1; i++) {
|
|
if (str[i] == token[0] && str[i+1] == token[1])
|
|
return &str[i];
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/* replace a given token in all the valid symbols. Use the sampled symbols
|
|
* to update the counts */
|
|
static void compress_symbols(unsigned char *str, int idx)
|
|
{
|
|
unsigned int i, len, size;
|
|
unsigned char *p1, *p2;
|
|
|
|
for (i = 0; i < table_cnt; i++) {
|
|
|
|
len = table[i].len;
|
|
p1 = table[i].sym;
|
|
|
|
/* find the token on the symbol */
|
|
p2 = find_token(p1, len, str);
|
|
if (!p2) continue;
|
|
|
|
/* decrease the counts for this symbol's tokens */
|
|
forget_symbol(table[i].sym, len);
|
|
|
|
size = len;
|
|
|
|
do {
|
|
*p2 = idx;
|
|
p2++;
|
|
size -= (p2 - p1);
|
|
memmove(p2, p2 + 1, size);
|
|
p1 = p2;
|
|
len--;
|
|
|
|
if (size < 2) break;
|
|
|
|
/* find the token on the symbol */
|
|
p2 = find_token(p1, size, str);
|
|
|
|
} while (p2);
|
|
|
|
table[i].len = len;
|
|
|
|
/* increase the counts for this symbol's new tokens */
|
|
learn_symbol(table[i].sym, len);
|
|
}
|
|
}
|
|
|
|
/* search the token with the maximum profit */
|
|
static int find_best_token(void)
|
|
{
|
|
int i, best, bestprofit;
|
|
|
|
bestprofit=-10000;
|
|
best = 0;
|
|
|
|
for (i = 0; i < 0x10000; i++) {
|
|
if (token_profit[i] > bestprofit) {
|
|
best = i;
|
|
bestprofit = token_profit[i];
|
|
}
|
|
}
|
|
return best;
|
|
}
|
|
|
|
/* this is the core of the algorithm: calculate the "best" table */
|
|
static void optimize_result(void)
|
|
{
|
|
int i, best;
|
|
|
|
/* using the '\0' symbol last allows compress_symbols to use standard
|
|
* fast string functions */
|
|
for (i = 255; i >= 0; i--) {
|
|
|
|
/* if this table slot is empty (it is not used by an actual
|
|
* original char code */
|
|
if (!best_table_len[i]) {
|
|
|
|
/* find the token with the breates profit value */
|
|
best = find_best_token();
|
|
|
|
/* place it in the "best" table */
|
|
best_table_len[i] = 2;
|
|
best_table[i][0] = best & 0xFF;
|
|
best_table[i][1] = (best >> 8) & 0xFF;
|
|
|
|
/* replace this token in all the valid symbols */
|
|
compress_symbols(best_table[i], i);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* start by placing the symbols that are actually used on the table */
|
|
static void insert_real_symbols_in_table(void)
|
|
{
|
|
unsigned int i, j, c;
|
|
|
|
memset(best_table, 0, sizeof(best_table));
|
|
memset(best_table_len, 0, sizeof(best_table_len));
|
|
|
|
for (i = 0; i < table_cnt; i++) {
|
|
for (j = 0; j < table[i].len; j++) {
|
|
c = table[i].sym[j];
|
|
best_table[c][0]=c;
|
|
best_table_len[c]=1;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void optimize_token_table(void)
|
|
{
|
|
build_initial_tok_table();
|
|
|
|
insert_real_symbols_in_table();
|
|
|
|
/* When valid symbol is not registered, exit to error */
|
|
if (!table_cnt) {
|
|
fprintf(stderr, "No valid symbol.\n");
|
|
exit(1);
|
|
}
|
|
|
|
optimize_result();
|
|
}
|
|
|
|
/* guess for "linker script provide" symbol */
|
|
static int may_be_linker_script_provide_symbol(const struct sym_entry *se)
|
|
{
|
|
const char *symbol = (char *)se->sym + 1;
|
|
int len = se->len - 1;
|
|
|
|
if (len < 8)
|
|
return 0;
|
|
|
|
if (symbol[0] != '_' || symbol[1] != '_')
|
|
return 0;
|
|
|
|
/* __start_XXXXX */
|
|
if (!memcmp(symbol + 2, "start_", 6))
|
|
return 1;
|
|
|
|
/* __stop_XXXXX */
|
|
if (!memcmp(symbol + 2, "stop_", 5))
|
|
return 1;
|
|
|
|
/* __end_XXXXX */
|
|
if (!memcmp(symbol + 2, "end_", 4))
|
|
return 1;
|
|
|
|
/* __XXXXX_start */
|
|
if (!memcmp(symbol + len - 6, "_start", 6))
|
|
return 1;
|
|
|
|
/* __XXXXX_end */
|
|
if (!memcmp(symbol + len - 4, "_end", 4))
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int prefix_underscores_count(const char *str)
|
|
{
|
|
const char *tail = str;
|
|
|
|
while (*tail == '_')
|
|
tail++;
|
|
|
|
return tail - str;
|
|
}
|
|
|
|
static int compare_symbols(const void *a, const void *b)
|
|
{
|
|
const struct sym_entry *sa;
|
|
const struct sym_entry *sb;
|
|
int wa, wb;
|
|
|
|
sa = a;
|
|
sb = b;
|
|
|
|
/* sort by address first */
|
|
if (sa->addr > sb->addr)
|
|
return 1;
|
|
if (sa->addr < sb->addr)
|
|
return -1;
|
|
|
|
/* sort by "weakness" type */
|
|
wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W');
|
|
wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W');
|
|
if (wa != wb)
|
|
return wa - wb;
|
|
|
|
/* sort by "linker script provide" type */
|
|
wa = may_be_linker_script_provide_symbol(sa);
|
|
wb = may_be_linker_script_provide_symbol(sb);
|
|
if (wa != wb)
|
|
return wa - wb;
|
|
|
|
/* sort by the number of prefix underscores */
|
|
wa = prefix_underscores_count((const char *)sa->sym + 1);
|
|
wb = prefix_underscores_count((const char *)sb->sym + 1);
|
|
if (wa != wb)
|
|
return wa - wb;
|
|
|
|
/* sort by initial order, so that other symbols are left undisturbed */
|
|
return sa->start_pos - sb->start_pos;
|
|
}
|
|
|
|
static void sort_symbols(void)
|
|
{
|
|
qsort(table, table_cnt, sizeof(struct sym_entry), compare_symbols);
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
if (argc >= 2) {
|
|
int i;
|
|
for (i = 1; i < argc; i++) {
|
|
if(strcmp(argv[i], "--all-symbols") == 0)
|
|
all_symbols = 1;
|
|
else if (strncmp(argv[i], "--symbol-prefix=", 16) == 0) {
|
|
char *p = &argv[i][16];
|
|
/* skip quote */
|
|
if ((*p == '"' && *(p+2) == '"') || (*p == '\'' && *(p+2) == '\''))
|
|
p++;
|
|
symbol_prefix_char = *p;
|
|
} else
|
|
usage();
|
|
}
|
|
} else if (argc != 1)
|
|
usage();
|
|
|
|
read_map(stdin);
|
|
sort_symbols();
|
|
optimize_token_table();
|
|
write_src();
|
|
|
|
return 0;
|
|
}
|