kernel26-2.6.12-alx-r9/scripts/kallsyms.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;
}
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	* ChangeLog:
11	*
12	* (25/Aug/2004) Paulo Marques <pmarques@grupopie.com>
13	* Changed the compression method from stem compression to "table lookup"
14	* compression
15	*
16	* Table compression uses all the unused char codes on the symbols and
17	* maps these to the most used substrings (tokens). For instance, it might
18	* map char code 0xF7 to represent "write_" and then in every symbol where
19	* "write_" appears it can be replaced by 0xF7, saving 5 bytes.
20	* The used codes themselves are also placed in the table so that the
21	* decompresion can work without "special cases".
22	* Applied to kernel symbols, this usually produces a compression ratio
23	* of about 50%.
24	*
25	*/
26
27	#include <stdio.h>
28	#include <stdlib.h>
29	#include <string.h>
30	#include <ctype.h>
31
32	/* maximum token length used. It doesn't pay to increase it a lot, because
33	* very long substrings probably don't repeat themselves too often. */
34	#define MAX_TOK_SIZE 11
35	#define KSYM_NAME_LEN 127
36
37	/* we use only a subset of the complete symbol table to gather the token count,
38	* to speed up compression, at the expense of a little compression ratio */
39	#define WORKING_SET 1024
40
41	/* first find the best token only on the list of tokens that would profit more
42	* than GOOD_BAD_THRESHOLD. Only if this list is empty go to the "bad" list.
43	* Increasing this value will put less tokens on the "good" list, so the search
44	* is faster. However, if the good list runs out of tokens, we must painfully
45	* search the bad list. */
46	#define GOOD_BAD_THRESHOLD 10
47
48	/* token hash parameters */
49	#define HASH_BITS 18
50	#define HASH_TABLE_SIZE (1 << HASH_BITS)
51	#define HASH_MASK (HASH_TABLE_SIZE - 1)
52	#define HASH_BASE_OFFSET 2166136261U
53	#define HASH_FOLD(a) ((a)&(HASH_MASK))
54
55	/* flags to mark symbols */
56	#define SYM_FLAG_VALID 1
57	#define SYM_FLAG_SAMPLED 2
58
59	struct sym_entry {
60	unsigned long long addr;
61	char type;
62	unsigned char flags;
63	unsigned char len;
64	unsigned char *sym;
65	};
66
67
68	static struct sym_entry *table;
69	static int size, cnt;
70	static unsigned long long _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;
71	static int all_symbols = 0;
72	static char symbol_prefix_char = '\0';
73
74	struct token {
75	unsigned char data[MAX_TOK_SIZE];
76	unsigned char len;
77	/* profit: the number of bytes that could be saved by inserting this
78	* token into the table */
79	int profit;
80	struct token next; / next token on the hash list */
81	struct token right; / next token on the good/bad list */
82	struct token left; / previous token on the good/bad list */
83	struct token smaller; / token that is less one letter than this one */
84	};
85
86	struct token bad_head, good_head;
87	struct token *hash_table[HASH_TABLE_SIZE];
88
89	/* the table that holds the result of the compression */
90	unsigned char best_table[256][MAX_TOK_SIZE+1];
91	unsigned char best_table_len[256];
92
93
94	static void
95	usage(void)
96	{
97	fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n");
98	exit(1);
99	}
100
101	/*
102	* This ignores the intensely annoying "mapping symbols" found
103	* in ARM ELF files: $a, $t and $d.
104	*/
105	static inline int
106	is_arm_mapping_symbol(const char *str)
107	{
108	return str[0] == '$' && strchr("atd", str[1])
109	&& (str[2] == '\0' \|\| str[2] == '.');
110	}
111
112	static int
113	read_symbol(FILE in, struct sym_entry s)
114	{
115	char str[500];
116	char *sym;
117	int rc;
118
119	rc = fscanf(in, "%llx %c %499s\n", &s->addr, &s->type, str);
120	if (rc != 3) {
121	if (rc != EOF) {
122	/* skip line */
123	fgets(str, 500, in);
124	}
125	return -1;
126	}
127
128	sym = str;
129	/* skip prefix char */
130	if (symbol_prefix_char && str[0] == symbol_prefix_char)
131	sym++;
132
133	/* Ignore most absolute/undefined (?) symbols. */
134	if (strcmp(sym, "_stext") == 0)
135	_stext = s->addr;
136	else if (strcmp(sym, "_etext") == 0)
137	_etext = s->addr;
138	else if (strcmp(sym, "_sinittext") == 0)
139	_sinittext = s->addr;
140	else if (strcmp(sym, "_einittext") == 0)
141	_einittext = s->addr;
142	else if (strcmp(sym, "_sextratext") == 0)
143	_sextratext = s->addr;
144	else if (strcmp(sym, "_eextratext") == 0)
145	_eextratext = s->addr;
146	else if (toupper(s->type) == 'A')
147	{
148	/* Keep these useful absolute symbols */
149	if (strcmp(sym, "__kernel_syscall_via_break") &&
150	strcmp(sym, "__kernel_syscall_via_epc") &&
151	strcmp(sym, "__kernel_sigtramp") &&
152	strcmp(sym, "__gp"))
153	return -1;
154
155	}
156	else if (toupper(s->type) == 'U' \|\|
157	is_arm_mapping_symbol(sym))
158	return -1;
159
160	/* include the type field in the symbol name, so that it gets
161	* compressed together */
162	s->len = strlen(str) + 1;
163	s->sym = (char *) malloc(s->len + 1);
164	strcpy(s->sym + 1, str);
165	s->sym[0] = s->type;
166
167	return 0;
168	}
169
170	static int
171	symbol_valid(struct sym_entry *s)
172	{
173	/* Symbols which vary between passes. Passes 1 and 2 must have
174	* identical symbol lists. The kallsyms_* symbols below are only added
175	* after pass 1, they would be included in pass 2 when --all-symbols is
176	* specified so exclude them to get a stable symbol list.
177	*/
178	static char *special_symbols[] = {
179	"kallsyms_addresses",
180	"kallsyms_num_syms",
181	"kallsyms_names",
182	"kallsyms_markers",
183	"kallsyms_token_table",
184	"kallsyms_token_index",
185
186	/* Exclude linker generated symbols which vary between passes */
187	"_SDA_BASE_", /* ppc */
188	"_SDA2_BASE_", /* ppc */
189	NULL };
190	int i;
191	int offset = 1;
192
193	/* skip prefix char */
194	if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char)
195	offset++;
196
197	/* if --all-symbols is not specified, then symbols outside the text
198	* and inittext sections are discarded */
199	if (!all_symbols) {
200	if ((s->addr < _stext \|\| s->addr > _etext)
201	&& (s->addr < _sinittext \|\| s->addr > _einittext)
202	&& (s->addr < _sextratext \|\| s->addr > _eextratext))
203	return 0;
204	/* Corner case. Discard any symbols with the same value as
205	* _etext _einittext or _eextratext; they can move between pass
206	* 1 and 2 when the kallsyms data are added. If these symbols
207	* move then they may get dropped in pass 2, which breaks the
208	* kallsyms rules.
209	*/
210	if ((s->addr == _etext && strcmp(s->sym + offset, "_etext")) \|\|
211	(s->addr == _einittext && strcmp(s->sym + offset, "_einittext")) \|\|
212	(s->addr == _eextratext && strcmp(s->sym + offset, "_eextratext")))
213	return 0;
214	}
215
216	/* Exclude symbols which vary between passes. */
217	if (strstr(s->sym + offset, "_compiled."))
218	return 0;
219
220	for (i = 0; special_symbols[i]; i++)
221	if( strcmp(s->sym + offset, special_symbols[i]) == 0 )
222	return 0;
223
224	return 1;
225	}
226
227	static void
228	read_map(FILE *in)
229	{
230	while (!feof(in)) {
231	if (cnt >= size) {
232	size += 10000;
233	table = realloc(table, sizeof(table) size);
234	if (!table) {
235	fprintf(stderr, "out of memory\n");
236	exit (1);
237	}
238	}
239	if (read_symbol(in, &table[cnt]) == 0)
240	cnt++;
241	}
242	}
243
244	static void output_label(char *label)
245	{
246	if (symbol_prefix_char)
247	printf(".globl %c%s\n", symbol_prefix_char, label);
248	else
249	printf(".globl %s\n", label);
250	printf("\tALGN\n");
251	if (symbol_prefix_char)
252	printf("%c%s:\n", symbol_prefix_char, label);
253	else
254	printf("%s:\n", label);
255	}
256
257	/* uncompress a compressed symbol. When this function is called, the best table
258	* might still be compressed itself, so the function needs to be recursive */
259	static int expand_symbol(unsigned char data, int len, char result)
260	{
261	int c, rlen, total=0;
262
263	while (len) {
264	c = *data;
265	/* if the table holds a single char that is the same as the one
266	* we are looking for, then end the search */
267	if (best_table[c][0]==c && best_table_len[c]==1) {
268	*result++ = c;
269	total++;
270	} else {
271	/* if not, recurse and expand */
272	rlen = expand_symbol(best_table[c], best_table_len[c], result);
273	total += rlen;
274	result += rlen;
275	}
276	data++;
277	len--;
278	}
279	*result=0;
280
281	return total;
282	}
283
284	static void
285	write_src(void)
286	{
287	int i, k, off, valid;
288	unsigned int best_idx[256];
289	unsigned int *markers;
290	char buf[KSYM_NAME_LEN+1];
291
292	printf("#include <asm/types.h>\n");
293	printf("#if BITS_PER_LONG == 64\n");
294	printf("#define PTR .quad\n");
295	printf("#define ALGN .align 8\n");
296	printf("#else\n");
297	printf("#define PTR .long\n");
298	printf("#define ALGN .align 4\n");
299	printf("#endif\n");
300
301	printf(".data\n");
302
303	output_label("kallsyms_addresses");
304	valid = 0;
305	for (i = 0; i < cnt; i++) {
306	if (table[i].flags & SYM_FLAG_VALID) {
307	printf("\tPTR\t%#llx\n", table[i].addr);
308	valid++;
309	}
310	}
311	printf("\n");
312
313	output_label("kallsyms_num_syms");
314	printf("\tPTR\t%d\n", valid);
315	printf("\n");
316
317	/* table of offset markers, that give the offset in the compressed stream
318	* every 256 symbols */
319	markers = (unsigned int ) malloc(sizeof(unsigned int)((valid + 255) / 256));
320
321	output_label("kallsyms_names");
322	valid = 0;
323	off = 0;
324	for (i = 0; i < cnt; i++) {
325
326	if (!table[i].flags & SYM_FLAG_VALID)
327	continue;
328
329	if ((valid & 0xFF) == 0)
330	markers[valid >> 8] = off;
331
332	printf("\t.byte 0x%02x", table[i].len);
333	for (k = 0; k < table[i].len; k++)
334	printf(", 0x%02x", table[i].sym[k]);
335	printf("\n");
336
337	off += table[i].len + 1;
338	valid++;
339	}
340	printf("\n");
341
342	output_label("kallsyms_markers");
343	for (i = 0; i < ((valid + 255) >> 8); i++)
344	printf("\tPTR\t%d\n", markers[i]);
345	printf("\n");
346
347	free(markers);
348
349	output_label("kallsyms_token_table");
350	off = 0;
351	for (i = 0; i < 256; i++) {
352	best_idx[i] = off;
353	expand_symbol(best_table[i],best_table_len[i],buf);
354	printf("\t.asciz\t\"%s\"\n", buf);
355	off += strlen(buf) + 1;
356	}
357	printf("\n");
358
359	output_label("kallsyms_token_index");
360	for (i = 0; i < 256; i++)
361	printf("\t.short\t%d\n", best_idx[i]);
362	printf("\n");
363	}
364
365
366	/* table lookup compression functions */
367
368	static inline unsigned int rehash_token(unsigned int hash, unsigned char data)
369	{
370	return ((hash * 16777619) ^ data);
371	}
372
373	static unsigned int hash_token(unsigned char *data, int len)
374	{
375	unsigned int hash=HASH_BASE_OFFSET;
376	int i;
377
378	for (i = 0; i < len; i++)
379	hash = rehash_token(hash, data[i]);
380
381	return HASH_FOLD(hash);
382	}
383
384	/* find a token given its data and hash value */
385	static struct token find_token_hash(unsigned char data, int len, unsigned int hash)
386	{
387	struct token *ptr;
388
389	ptr = hash_table[hash];
390
391	while (ptr) {
392	if ((ptr->len == len) && (memcmp(ptr->data, data, len) == 0))
393	return ptr;
394	ptr=ptr->next;
395	}
396
397	return NULL;
398	}
399
400	static inline void insert_token_in_group(struct token head, struct token ptr)
401	{
402	ptr->right = head->right;
403	ptr->right->left = ptr;
404	head->right = ptr;
405	ptr->left = head;
406	}
407
408	static inline void remove_token_from_group(struct token *ptr)
409	{
410	ptr->left->right = ptr->right;
411	ptr->right->left = ptr->left;
412	}
413
414
415	/* build the counts for all the tokens that start with "data", and have lenghts
416	* from 2 to "len" */
417	static void learn_token(unsigned char *data, int len)
418	{
419	struct token ptr,last_ptr;
420	int i, newprofit;
421	unsigned int hash = HASH_BASE_OFFSET;
422	unsigned int hashes[MAX_TOK_SIZE + 1];
423
424	if (len > MAX_TOK_SIZE)
425	len = MAX_TOK_SIZE;
426
427	/* calculate and store the hash values for all the sub-tokens */
428	hash = rehash_token(hash, data[0]);
429	for (i = 2; i <= len; i++) {
430	hash = rehash_token(hash, data[i-1]);
431	hashes[i] = HASH_FOLD(hash);
432	}
433
434	last_ptr = NULL;
435	ptr = NULL;
436
437	for (i = len; i >= 2; i--) {
438	hash = hashes[i];
439
440	if (!ptr) ptr = find_token_hash(data, i, hash);
441
442	if (!ptr) {
443	/* create a new token entry */
444	ptr = (struct token ) malloc(sizeof(ptr));
445
446	memcpy(ptr->data, data, i);
447	ptr->len = i;
448
449	/* when we create an entry, it's profit is 0 because
450	* we also take into account the size of the token on
451	* the compressed table. We then subtract GOOD_BAD_THRESHOLD
452	* so that the test to see if this token belongs to
453	* the good or bad list, is a comparison to zero */
454	ptr->profit = -GOOD_BAD_THRESHOLD;
455
456	ptr->next = hash_table[hash];
457	hash_table[hash] = ptr;
458
459	insert_token_in_group(&bad_head, ptr);
460
461	ptr->smaller = NULL;
462	} else {
463	newprofit = ptr->profit + (ptr->len - 1);
464	/* check to see if this token needs to be moved to a
465	* different list */
466	if((ptr->profit < 0) && (newprofit >= 0)) {
467	remove_token_from_group(ptr);
468	insert_token_in_group(&good_head,ptr);
469	}
470	ptr->profit = newprofit;
471	}
472
473	if (last_ptr) last_ptr->smaller = ptr;
474	last_ptr = ptr;
475
476	ptr = ptr->smaller;
477	}
478	}
479
480	/* decrease the counts for all the tokens that start with "data", and have lenghts
481	* from 2 to "len". This function is much simpler than learn_token because we have
482	* more guarantees (tho tokens exist, the ->smaller pointer is set, etc.)
483	* The two separate functions exist only because of compression performance */
484	static void forget_token(unsigned char *data, int len)
485	{
486	struct token *ptr;
487	int i, newprofit;
488	unsigned int hash=0;
489
490	if (len > MAX_TOK_SIZE) len = MAX_TOK_SIZE;
491
492	hash = hash_token(data, len);
493	ptr = find_token_hash(data, len, hash);
494
495	for (i = len; i >= 2; i--) {
496
497	newprofit = ptr->profit - (ptr->len - 1);
498	if ((ptr->profit >= 0) && (newprofit < 0)) {
499	remove_token_from_group(ptr);
500	insert_token_in_group(&bad_head, ptr);
501	}
502	ptr->profit=newprofit;
503
504	ptr=ptr->smaller;
505	}
506	}
507
508	/* count all the possible tokens in a symbol */
509	static void learn_symbol(unsigned char *symbol, int len)
510	{
511	int i;
512
513	for (i = 0; i < len - 1; i++)
514	learn_token(symbol + i, len - i);
515	}
516
517	/* decrease the count for all the possible tokens in a symbol */
518	static void forget_symbol(unsigned char *symbol, int len)
519	{
520	int i;
521
522	for (i = 0; i < len - 1; i++)
523	forget_token(symbol + i, len - i);
524	}
525
526	/* set all the symbol flags and do the initial token count */
527	static void build_initial_tok_table(void)
528	{
529	int i, use_it, valid;
530
531	valid = 0;
532	for (i = 0; i < cnt; i++) {
533	table[i].flags = 0;
534	if ( symbol_valid(&table[i]) ) {
535	table[i].flags \|= SYM_FLAG_VALID;
536	valid++;
537	}
538	}
539
540	use_it = 0;
541	for (i = 0; i < cnt; i++) {
542
543	/* subsample the available symbols. This method is almost like
544	* a Bresenham's algorithm to get uniformly distributed samples
545	* across the symbol table */
546	if (table[i].flags & SYM_FLAG_VALID) {
547
548	use_it += WORKING_SET;
549
550	if (use_it >= valid) {
551	table[i].flags \|= SYM_FLAG_SAMPLED;
552	use_it -= valid;
553	}
554	}
555	if (table[i].flags & SYM_FLAG_SAMPLED)
556	learn_symbol(table[i].sym, table[i].len);
557	}
558	}
559
560	/* replace a given token in all the valid symbols. Use the sampled symbols
561	* to update the counts */
562	static void compress_symbols(unsigned char *str, int tlen, int idx)
563	{
564	int i, len, learn, size;
565	unsigned char *p;
566
567	for (i = 0; i < cnt; i++) {
568
569	if (!(table[i].flags & SYM_FLAG_VALID)) continue;
570
571	len = table[i].len;
572	learn = 0;
573	p = table[i].sym;
574
575	do {
576	/* find the token on the symbol */
577	p = (unsigned char ) strstr((char ) p, (char *) str);
578	if (!p) break;
579
580	if (!learn) {
581	/* if this symbol was used to count, decrease it */
582	if (table[i].flags & SYM_FLAG_SAMPLED)
583	forget_symbol(table[i].sym, len);
584	learn = 1;
585	}
586
587	*p = idx;
588	size = (len - (p - table[i].sym)) - tlen + 1;
589	memmove(p + 1, p + tlen, size);
590	p++;
591	len -= tlen - 1;
592
593	} while (size >= tlen);
594
595	if(learn) {
596	table[i].len = len;
597	/* if this symbol was used to count, learn it again */
598	if(table[i].flags & SYM_FLAG_SAMPLED)
599	learn_symbol(table[i].sym, len);
600	}
601	}
602	}
603
604	/* search the token with the maximum profit */
605	static struct token *find_best_token(void)
606	{
607	struct token ptr,best,*head;
608	int bestprofit;
609
610	bestprofit=-10000;
611
612	/* failsafe: if the "good" list is empty search from the "bad" list */
613	if(good_head.right == &good_head) head = &bad_head;
614	else head = &good_head;
615
616	ptr = head->right;
617	best = NULL;
618	while (ptr != head) {
619	if (ptr->profit > bestprofit) {
620	bestprofit = ptr->profit;
621	best = ptr;
622	}
623	ptr = ptr->right;
624	}
625
626	return best;
627	}
628
629	/* this is the core of the algorithm: calculate the "best" table */
630	static void optimize_result(void)
631	{
632	struct token *best;
633	int i;
634
635	/* using the '\0' symbol last allows compress_symbols to use standard
636	* fast string functions */
637	for (i = 255; i >= 0; i--) {
638
639	/* if this table slot is empty (it is not used by an actual
640	* original char code */
641	if (!best_table_len[i]) {
642
643	/* find the token with the breates profit value */
644	best = find_best_token();
645
646	/* place it in the "best" table */
647	best_table_len[i] = best->len;
648	memcpy(best_table[i], best->data, best_table_len[i]);
649	/* zero terminate the token so that we can use strstr
650	in compress_symbols */
651	best_table[i][best_table_len[i]]='\0';
652
653	/* replace this token in all the valid symbols */
654	compress_symbols(best_table[i], best_table_len[i], i);
655	}
656	}
657	}
658
659	/* start by placing the symbols that are actually used on the table */
660	static void insert_real_symbols_in_table(void)
661	{
662	int i, j, c;
663
664	memset(best_table, 0, sizeof(best_table));
665	memset(best_table_len, 0, sizeof(best_table_len));
666
667	for (i = 0; i < cnt; i++) {
668	if (table[i].flags & SYM_FLAG_VALID) {
669	for (j = 0; j < table[i].len; j++) {
670	c = table[i].sym[j];
671	best_table[c][0]=c;
672	best_table_len[c]=1;
673	}
674	}
675	}
676	}
677
678	static void optimize_token_table(void)
679	{
680	memset(hash_table, 0, sizeof(hash_table));
681
682	good_head.left = &good_head;
683	good_head.right = &good_head;
684
685	bad_head.left = &bad_head;
686	bad_head.right = &bad_head;
687
688	build_initial_tok_table();
689
690	insert_real_symbols_in_table();
691
692	/* When valid symbol is not registered, exit to error */
693	if (good_head.left == good_head.right &&
694	bad_head.left == bad_head.right) {
695	fprintf(stderr, "No valid symbol.\n");
696	exit(1);
697	}
698
699	optimize_result();
700	}
701
702
703	int
704	main(int argc, char **argv)
705	{
706	if (argc >= 2) {
707	int i;
708	for (i = 1; i < argc; i++) {
709	if(strcmp(argv[i], "--all-symbols") == 0)
710	all_symbols = 1;
711	else if (strncmp(argv[i], "--symbol-prefix=", 16) == 0) {
712	char *p = &argv[i][16];
713	/* skip quote */
714	if ((p == '"' && (p+2) == '"') \|\| (p == '\'' && (p+2) == '\''))
715	p++;
716	symbol_prefix_char = *p;
717	} else
718	usage();
719	}
720	} else if (argc != 1)
721	usage();
722
723	read_map(stdin);
724	optimize_token_table();
725	write_src();
726
727	return 0;
728	}