android_kernel_motorola_sm6225/scripts/kallsyms.c
David Woodhouse 075d6eb16d [PATCH] ppc32: platform-specific functions missing from kallsyms.
The PPC32 kernel puts platform-specific functions into separate sections so
that unneeded parts of it can be freed when we've booted and actually
worked out what we're running on today.

This makes kallsyms ignore those functions, because they're not between
_[se]text or _[se]inittext.  Rather than teaching kallsyms about the
various pmac/chrp/etc sections, this patch adds '_[se]extratext' markers
for kallsyms.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-05 16:36:31 -07:00

728 lines
18 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
*
* ChangeLog:
*
* (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
* Changed the compression method from stem compression to "table lookup"
* compression
*
* 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>
/* maximum token length used. It doesn't pay to increase it a lot, because
* very long substrings probably don't repeat themselves too often. */
#define MAX_TOK_SIZE 11
#define KSYM_NAME_LEN 127
/* we use only a subset of the complete symbol table to gather the token count,
* to speed up compression, at the expense of a little compression ratio */
#define WORKING_SET 1024
/* first find the best token only on the list of tokens that would profit more
* than GOOD_BAD_THRESHOLD. Only if this list is empty go to the "bad" list.
* Increasing this value will put less tokens on the "good" list, so the search
* is faster. However, if the good list runs out of tokens, we must painfully
* search the bad list. */
#define GOOD_BAD_THRESHOLD 10
/* token hash parameters */
#define HASH_BITS 18
#define HASH_TABLE_SIZE (1 << HASH_BITS)
#define HASH_MASK (HASH_TABLE_SIZE - 1)
#define HASH_BASE_OFFSET 2166136261U
#define HASH_FOLD(a) ((a)&(HASH_MASK))
/* flags to mark symbols */
#define SYM_FLAG_VALID 1
#define SYM_FLAG_SAMPLED 2
struct sym_entry {
unsigned long long addr;
char type;
unsigned char flags;
unsigned char len;
unsigned char *sym;
};
static struct sym_entry *table;
static int size, cnt;
static unsigned long long _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;
static int all_symbols = 0;
static char symbol_prefix_char = '\0';
struct token {
unsigned char data[MAX_TOK_SIZE];
unsigned char len;
/* profit: the number of bytes that could be saved by inserting this
* token into the table */
int profit;
struct token *next; /* next token on the hash list */
struct token *right; /* next token on the good/bad list */
struct token *left; /* previous token on the good/bad list */
struct token *smaller; /* token that is less one letter than this one */
};
struct token bad_head, good_head;
struct token *hash_table[HASH_TABLE_SIZE];
/* the table that holds the result of the compression */
unsigned char best_table[256][MAX_TOK_SIZE+1];
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(FILE *in, struct sym_entry *s)
{
char str[500];
char *sym;
int rc;
rc = fscanf(in, "%llx %c %499s\n", &s->addr, &s->type, str);
if (rc != 3) {
if (rc != EOF) {
/* skip line */
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, "_stext") == 0)
_stext = s->addr;
else if (strcmp(sym, "_etext") == 0)
_etext = s->addr;
else if (strcmp(sym, "_sinittext") == 0)
_sinittext = s->addr;
else if (strcmp(sym, "_einittext") == 0)
_einittext = s->addr;
else if (strcmp(sym, "_sextratext") == 0)
_sextratext = s->addr;
else if (strcmp(sym, "_eextratext") == 0)
_eextratext = s->addr;
else if (toupper(s->type) == '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(s->type) == 'U' ||
is_arm_mapping_symbol(sym))
return -1;
/* include the type field in the symbol name, so that it gets
* compressed together */
s->len = strlen(str) + 1;
s->sym = (char *) malloc(s->len + 1);
strcpy(s->sym + 1, str);
s->sym[0] = s->type;
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 ((s->addr < _stext || s->addr > _etext)
&& (s->addr < _sinittext || s->addr > _einittext)
&& (s->addr < _sextratext || s->addr > _eextratext))
return 0;
/* Corner case. Discard any symbols with the same value as
* _etext _einittext or _eextratext; 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 == _etext && strcmp(s->sym + offset, "_etext")) ||
(s->addr == _einittext && strcmp(s->sym + offset, "_einittext")) ||
(s->addr == _eextratext && strcmp(s->sym + offset, "_eextratext")))
return 0;
}
/* Exclude symbols which vary between passes. */
if (strstr(s->sym + offset, "_compiled."))
return 0;
for (i = 0; special_symbols[i]; i++)
if( strcmp(s->sym + offset, special_symbols[i]) == 0 )
return 0;
return 1;
}
static void
read_map(FILE *in)
{
while (!feof(in)) {
if (cnt >= size) {
size += 10000;
table = realloc(table, sizeof(*table) * size);
if (!table) {
fprintf(stderr, "out of memory\n");
exit (1);
}
}
if (read_symbol(in, &table[cnt]) == 0)
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)
{
int i, k, off, valid;
unsigned int best_idx[256];
unsigned int *markers;
char buf[KSYM_NAME_LEN+1];
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(".data\n");
output_label("kallsyms_addresses");
valid = 0;
for (i = 0; i < cnt; i++) {
if (table[i].flags & SYM_FLAG_VALID) {
printf("\tPTR\t%#llx\n", table[i].addr);
valid++;
}
}
printf("\n");
output_label("kallsyms_num_syms");
printf("\tPTR\t%d\n", valid);
printf("\n");
/* table of offset markers, that give the offset in the compressed stream
* every 256 symbols */
markers = (unsigned int *) malloc(sizeof(unsigned int)*((valid + 255) / 256));
output_label("kallsyms_names");
valid = 0;
off = 0;
for (i = 0; i < cnt; i++) {
if (!table[i].flags & SYM_FLAG_VALID)
continue;
if ((valid & 0xFF) == 0)
markers[valid >> 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;
valid++;
}
printf("\n");
output_label("kallsyms_markers");
for (i = 0; i < ((valid + 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 */
static inline unsigned int rehash_token(unsigned int hash, unsigned char data)
{
return ((hash * 16777619) ^ data);
}
static unsigned int hash_token(unsigned char *data, int len)
{
unsigned int hash=HASH_BASE_OFFSET;
int i;
for (i = 0; i < len; i++)
hash = rehash_token(hash, data[i]);
return HASH_FOLD(hash);
}
/* find a token given its data and hash value */
static struct token *find_token_hash(unsigned char *data, int len, unsigned int hash)
{
struct token *ptr;
ptr = hash_table[hash];
while (ptr) {
if ((ptr->len == len) && (memcmp(ptr->data, data, len) == 0))
return ptr;
ptr=ptr->next;
}
return NULL;
}
static inline void insert_token_in_group(struct token *head, struct token *ptr)
{
ptr->right = head->right;
ptr->right->left = ptr;
head->right = ptr;
ptr->left = head;
}
static inline void remove_token_from_group(struct token *ptr)
{
ptr->left->right = ptr->right;
ptr->right->left = ptr->left;
}
/* build the counts for all the tokens that start with "data", and have lenghts
* from 2 to "len" */
static void learn_token(unsigned char *data, int len)
{
struct token *ptr,*last_ptr;
int i, newprofit;
unsigned int hash = HASH_BASE_OFFSET;
unsigned int hashes[MAX_TOK_SIZE + 1];
if (len > MAX_TOK_SIZE)
len = MAX_TOK_SIZE;
/* calculate and store the hash values for all the sub-tokens */
hash = rehash_token(hash, data[0]);
for (i = 2; i <= len; i++) {
hash = rehash_token(hash, data[i-1]);
hashes[i] = HASH_FOLD(hash);
}
last_ptr = NULL;
ptr = NULL;
for (i = len; i >= 2; i--) {
hash = hashes[i];
if (!ptr) ptr = find_token_hash(data, i, hash);
if (!ptr) {
/* create a new token entry */
ptr = (struct token *) malloc(sizeof(*ptr));
memcpy(ptr->data, data, i);
ptr->len = i;
/* when we create an entry, it's profit is 0 because
* we also take into account the size of the token on
* the compressed table. We then subtract GOOD_BAD_THRESHOLD
* so that the test to see if this token belongs to
* the good or bad list, is a comparison to zero */
ptr->profit = -GOOD_BAD_THRESHOLD;
ptr->next = hash_table[hash];
hash_table[hash] = ptr;
insert_token_in_group(&bad_head, ptr);
ptr->smaller = NULL;
} else {
newprofit = ptr->profit + (ptr->len - 1);
/* check to see if this token needs to be moved to a
* different list */
if((ptr->profit < 0) && (newprofit >= 0)) {
remove_token_from_group(ptr);
insert_token_in_group(&good_head,ptr);
}
ptr->profit = newprofit;
}
if (last_ptr) last_ptr->smaller = ptr;
last_ptr = ptr;
ptr = ptr->smaller;
}
}
/* decrease the counts for all the tokens that start with "data", and have lenghts
* from 2 to "len". This function is much simpler than learn_token because we have
* more guarantees (tho tokens exist, the ->smaller pointer is set, etc.)
* The two separate functions exist only because of compression performance */
static void forget_token(unsigned char *data, int len)
{
struct token *ptr;
int i, newprofit;
unsigned int hash=0;
if (len > MAX_TOK_SIZE) len = MAX_TOK_SIZE;
hash = hash_token(data, len);
ptr = find_token_hash(data, len, hash);
for (i = len; i >= 2; i--) {
newprofit = ptr->profit - (ptr->len - 1);
if ((ptr->profit >= 0) && (newprofit < 0)) {
remove_token_from_group(ptr);
insert_token_in_group(&bad_head, ptr);
}
ptr->profit=newprofit;
ptr=ptr->smaller;
}
}
/* 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++)
learn_token(symbol + i, len - i);
}
/* 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++)
forget_token(symbol + i, len - i);
}
/* set all the symbol flags and do the initial token count */
static void build_initial_tok_table(void)
{
int i, use_it, valid;
valid = 0;
for (i = 0; i < cnt; i++) {
table[i].flags = 0;
if ( symbol_valid(&table[i]) ) {
table[i].flags |= SYM_FLAG_VALID;
valid++;
}
}
use_it = 0;
for (i = 0; i < cnt; i++) {
/* subsample the available symbols. This method is almost like
* a Bresenham's algorithm to get uniformly distributed samples
* across the symbol table */
if (table[i].flags & SYM_FLAG_VALID) {
use_it += WORKING_SET;
if (use_it >= valid) {
table[i].flags |= SYM_FLAG_SAMPLED;
use_it -= valid;
}
}
if (table[i].flags & SYM_FLAG_SAMPLED)
learn_symbol(table[i].sym, table[i].len);
}
}
/* 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 tlen, int idx)
{
int i, len, learn, size;
unsigned char *p;
for (i = 0; i < cnt; i++) {
if (!(table[i].flags & SYM_FLAG_VALID)) continue;
len = table[i].len;
learn = 0;
p = table[i].sym;
do {
/* find the token on the symbol */
p = (unsigned char *) strstr((char *) p, (char *) str);
if (!p) break;
if (!learn) {
/* if this symbol was used to count, decrease it */
if (table[i].flags & SYM_FLAG_SAMPLED)
forget_symbol(table[i].sym, len);
learn = 1;
}
*p = idx;
size = (len - (p - table[i].sym)) - tlen + 1;
memmove(p + 1, p + tlen, size);
p++;
len -= tlen - 1;
} while (size >= tlen);
if(learn) {
table[i].len = len;
/* if this symbol was used to count, learn it again */
if(table[i].flags & SYM_FLAG_SAMPLED)
learn_symbol(table[i].sym, len);
}
}
}
/* search the token with the maximum profit */
static struct token *find_best_token(void)
{
struct token *ptr,*best,*head;
int bestprofit;
bestprofit=-10000;
/* failsafe: if the "good" list is empty search from the "bad" list */
if(good_head.right == &good_head) head = &bad_head;
else head = &good_head;
ptr = head->right;
best = NULL;
while (ptr != head) {
if (ptr->profit > bestprofit) {
bestprofit = ptr->profit;
best = ptr;
}
ptr = ptr->right;
}
return best;
}
/* this is the core of the algorithm: calculate the "best" table */
static void optimize_result(void)
{
struct token *best;
int i;
/* 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] = best->len;
memcpy(best_table[i], best->data, best_table_len[i]);
/* zero terminate the token so that we can use strstr
in compress_symbols */
best_table[i][best_table_len[i]]='\0';
/* replace this token in all the valid symbols */
compress_symbols(best_table[i], best_table_len[i], i);
}
}
}
/* start by placing the symbols that are actually used on the table */
static void insert_real_symbols_in_table(void)
{
int i, j, c;
memset(best_table, 0, sizeof(best_table));
memset(best_table_len, 0, sizeof(best_table_len));
for (i = 0; i < cnt; i++) {
if (table[i].flags & SYM_FLAG_VALID) {
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)
{
memset(hash_table, 0, sizeof(hash_table));
good_head.left = &good_head;
good_head.right = &good_head;
bad_head.left = &bad_head;
bad_head.right = &bad_head;
build_initial_tok_table();
insert_real_symbols_in_table();
/* When valid symbol is not registered, exit to error */
if (good_head.left == good_head.right &&
bad_head.left == bad_head.right) {
fprintf(stderr, "No valid symbol.\n");
exit(1);
}
optimize_result();
}
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);
optimize_token_table();
write_src();
return 0;
}