xref: /linux/scripts/kallsyms.c (revision db10cb9b) 
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: kallsyms [--all-symbols] [--absolute-percpu]
9  *                         [--base-relative] [--lto-clang] in.map > out.S
10  *
11  *      Table compression uses all the unused char codes on the symbols and
12  *  maps these to the most used substrings (tokens). For instance, it might
13  *  map char code 0xF7 to represent "write_" and then in every symbol where
14  *  "write_" appears it can be replaced by 0xF7, saving 5 bytes.
15  *      The used codes themselves are also placed in the table so that the
16  *  decompresion can work without "special cases".
17  *      Applied to kernel symbols, this usually produces a compression ratio
18  *  of about 50%.
19  *
20  */
21 
22 #include <errno.h>
23 #include <getopt.h>
24 #include <stdbool.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <ctype.h>
29 #include <limits.h>
30 
31 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
32 
33 #define KSYM_NAME_LEN		512
34 
35 struct sym_entry {
36 	unsigned long long addr;
37 	unsigned int len;
38 	unsigned int seq;
39 	unsigned int start_pos;
40 	unsigned int percpu_absolute;
41 	unsigned char sym[];
42 };
43 
44 struct addr_range {
45 	const char *start_sym, *end_sym;
46 	unsigned long long start, end;
47 };
48 
49 static unsigned long long _text;
50 static unsigned long long relative_base;
51 static struct addr_range text_ranges[] = {
52 	{ "_stext",     "_etext"     },
53 	{ "_sinittext", "_einittext" },
54 };
55 #define text_range_text     (&text_ranges[0])
56 #define text_range_inittext (&text_ranges[1])
57 
58 static struct addr_range percpu_range = {
59 	"__per_cpu_start", "__per_cpu_end", -1ULL, 0
60 };
61 
62 static struct sym_entry **table;
63 static unsigned int table_size, table_cnt;
64 static int all_symbols;
65 static int absolute_percpu;
66 static int base_relative;
67 static int lto_clang;
68 
69 static int token_profit[0x10000];
70 
71 /* the table that holds the result of the compression */
72 static unsigned char best_table[256][2];
73 static unsigned char best_table_len[256];
74 
75 
76 static void usage(void)
77 {
78 	fprintf(stderr, "Usage: kallsyms [--all-symbols] [--absolute-percpu] "
79 			"[--base-relative] [--lto-clang] in.map > out.S\n");
80 	exit(1);
81 }
82 
83 static char *sym_name(const struct sym_entry *s)
84 {
85 	return (char *)s->sym + 1;
86 }
87 
88 static bool is_ignored_symbol(const char *name, char type)
89 {
90 	if (type == 'u' || type == 'n')
91 		return true;
92 
93 	if (toupper(type) == 'A') {
94 		/* Keep these useful absolute symbols */
95 		if (strcmp(name, "__kernel_syscall_via_break") &&
96 		    strcmp(name, "__kernel_syscall_via_epc") &&
97 		    strcmp(name, "__kernel_sigtramp") &&
98 		    strcmp(name, "__gp"))
99 			return true;
100 	}
101 
102 	return false;
103 }
104 
105 static void check_symbol_range(const char *sym, unsigned long long addr,
106 			       struct addr_range *ranges, int entries)
107 {
108 	size_t i;
109 	struct addr_range *ar;
110 
111 	for (i = 0; i < entries; ++i) {
112 		ar = &ranges[i];
113 
114 		if (strcmp(sym, ar->start_sym) == 0) {
115 			ar->start = addr;
116 			return;
117 		} else if (strcmp(sym, ar->end_sym) == 0) {
118 			ar->end = addr;
119 			return;
120 		}
121 	}
122 }
123 
124 static struct sym_entry *read_symbol(FILE *in, char **buf, size_t *buf_len)
125 {
126 	char *name, type, *p;
127 	unsigned long long addr;
128 	size_t len;
129 	ssize_t readlen;
130 	struct sym_entry *sym;
131 
132 	errno = 0;
133 	readlen = getline(buf, buf_len, in);
134 	if (readlen < 0) {
135 		if (errno) {
136 			perror("read_symbol");
137 			exit(EXIT_FAILURE);
138 		}
139 		return NULL;
140 	}
141 
142 	if ((*buf)[readlen - 1] == '\n')
143 		(*buf)[readlen - 1] = 0;
144 
145 	addr = strtoull(*buf, &p, 16);
146 
147 	if (*buf == p || *p++ != ' ' || !isascii((type = *p++)) || *p++ != ' ') {
148 		fprintf(stderr, "line format error\n");
149 		exit(EXIT_FAILURE);
150 	}
151 
152 	name = p;
153 	len = strlen(name);
154 
155 	if (len >= KSYM_NAME_LEN) {
156 		fprintf(stderr, "Symbol %s too long for kallsyms (%zu >= %d).\n"
157 				"Please increase KSYM_NAME_LEN both in kernel and kallsyms.c\n",
158 			name, len, KSYM_NAME_LEN);
159 		return NULL;
160 	}
161 
162 	if (strcmp(name, "_text") == 0)
163 		_text = addr;
164 
165 	/* Ignore most absolute/undefined (?) symbols. */
166 	if (is_ignored_symbol(name, type))
167 		return NULL;
168 
169 	check_symbol_range(name, addr, text_ranges, ARRAY_SIZE(text_ranges));
170 	check_symbol_range(name, addr, &percpu_range, 1);
171 
172 	/* include the type field in the symbol name, so that it gets
173 	 * compressed together */
174 	len++;
175 
176 	sym = malloc(sizeof(*sym) + len + 1);
177 	if (!sym) {
178 		fprintf(stderr, "kallsyms failure: "
179 			"unable to allocate required amount of memory\n");
180 		exit(EXIT_FAILURE);
181 	}
182 	sym->addr = addr;
183 	sym->len = len;
184 	sym->sym[0] = type;
185 	strcpy(sym_name(sym), name);
186 	sym->percpu_absolute = 0;
187 
188 	return sym;
189 }
190 
191 static int symbol_in_range(const struct sym_entry *s,
192 			   const struct addr_range *ranges, int entries)
193 {
194 	size_t i;
195 	const struct addr_range *ar;
196 
197 	for (i = 0; i < entries; ++i) {
198 		ar = &ranges[i];
199 
200 		if (s->addr >= ar->start && s->addr <= ar->end)
201 			return 1;
202 	}
203 
204 	return 0;
205 }
206 
207 static int symbol_valid(const struct sym_entry *s)
208 {
209 	const char *name = sym_name(s);
210 
211 	/* if --all-symbols is not specified, then symbols outside the text
212 	 * and inittext sections are discarded */
213 	if (!all_symbols) {
214 		if (symbol_in_range(s, text_ranges,
215 				    ARRAY_SIZE(text_ranges)) == 0)
216 			return 0;
217 		/* Corner case.  Discard any symbols with the same value as
218 		 * _etext _einittext; they can move between pass 1 and 2 when
219 		 * the kallsyms data are added.  If these symbols move then
220 		 * they may get dropped in pass 2, which breaks the kallsyms
221 		 * rules.
222 		 */
223 		if ((s->addr == text_range_text->end &&
224 		     strcmp(name, text_range_text->end_sym)) ||
225 		    (s->addr == text_range_inittext->end &&
226 		     strcmp(name, text_range_inittext->end_sym)))
227 			return 0;
228 	}
229 
230 	return 1;
231 }
232 
233 /* remove all the invalid symbols from the table */
234 static void shrink_table(void)
235 {
236 	unsigned int i, pos;
237 
238 	pos = 0;
239 	for (i = 0; i < table_cnt; i++) {
240 		if (symbol_valid(table[i])) {
241 			if (pos != i)
242 				table[pos] = table[i];
243 			pos++;
244 		} else {
245 			free(table[i]);
246 		}
247 	}
248 	table_cnt = pos;
249 
250 	/* When valid symbol is not registered, exit to error */
251 	if (!table_cnt) {
252 		fprintf(stderr, "No valid symbol.\n");
253 		exit(1);
254 	}
255 }
256 
257 static void read_map(const char *in)
258 {
259 	FILE *fp;
260 	struct sym_entry *sym;
261 	char *buf = NULL;
262 	size_t buflen = 0;
263 
264 	fp = fopen(in, "r");
265 	if (!fp) {
266 		perror(in);
267 		exit(1);
268 	}
269 
270 	while (!feof(fp)) {
271 		sym = read_symbol(fp, &buf, &buflen);
272 		if (!sym)
273 			continue;
274 
275 		sym->start_pos = table_cnt;
276 
277 		if (table_cnt >= table_size) {
278 			table_size += 10000;
279 			table = realloc(table, sizeof(*table) * table_size);
280 			if (!table) {
281 				fprintf(stderr, "out of memory\n");
282 				fclose(fp);
283 				exit (1);
284 			}
285 		}
286 
287 		table[table_cnt++] = sym;
288 	}
289 
290 	free(buf);
291 	fclose(fp);
292 }
293 
294 static void output_label(const char *label)
295 {
296 	printf(".globl %s\n", label);
297 	printf("\tALGN\n");
298 	printf("%s:\n", label);
299 }
300 
301 /* Provide proper symbols relocatability by their '_text' relativeness. */
302 static void output_address(unsigned long long addr)
303 {
304 	if (_text <= addr)
305 		printf("\tPTR\t_text + %#llx\n", addr - _text);
306 	else
307 		printf("\tPTR\t_text - %#llx\n", _text - addr);
308 }
309 
310 /* uncompress a compressed symbol. When this function is called, the best table
311  * might still be compressed itself, so the function needs to be recursive */
312 static int expand_symbol(const unsigned char *data, int len, char *result)
313 {
314 	int c, rlen, total=0;
315 
316 	while (len) {
317 		c = *data;
318 		/* if the table holds a single char that is the same as the one
319 		 * we are looking for, then end the search */
320 		if (best_table[c][0]==c && best_table_len[c]==1) {
321 			*result++ = c;
322 			total++;
323 		} else {
324 			/* if not, recurse and expand */
325 			rlen = expand_symbol(best_table[c], best_table_len[c], result);
326 			total += rlen;
327 			result += rlen;
328 		}
329 		data++;
330 		len--;
331 	}
332 	*result=0;
333 
334 	return total;
335 }
336 
337 static int symbol_absolute(const struct sym_entry *s)
338 {
339 	return s->percpu_absolute;
340 }
341 
342 static void cleanup_symbol_name(char *s)
343 {
344 	char *p;
345 
346 	/*
347 	 * ASCII[.]   = 2e
348 	 * ASCII[0-9] = 30,39
349 	 * ASCII[A-Z] = 41,5a
350 	 * ASCII[_]   = 5f
351 	 * ASCII[a-z] = 61,7a
352 	 *
353 	 * As above, replacing the first '.' in ".llvm." with '\0' does not
354 	 * affect the main sorting, but it helps us with subsorting.
355 	 */
356 	p = strstr(s, ".llvm.");
357 	if (p)
358 		*p = '\0';
359 }
360 
361 static int compare_names(const void *a, const void *b)
362 {
363 	int ret;
364 	const struct sym_entry *sa = *(const struct sym_entry **)a;
365 	const struct sym_entry *sb = *(const struct sym_entry **)b;
366 
367 	ret = strcmp(sym_name(sa), sym_name(sb));
368 	if (!ret) {
369 		if (sa->addr > sb->addr)
370 			return 1;
371 		else if (sa->addr < sb->addr)
372 			return -1;
373 
374 		/* keep old order */
375 		return (int)(sa->seq - sb->seq);
376 	}
377 
378 	return ret;
379 }
380 
381 static void sort_symbols_by_name(void)
382 {
383 	qsort(table, table_cnt, sizeof(table[0]), compare_names);
384 }
385 
386 static void write_src(void)
387 {
388 	unsigned int i, k, off;
389 	unsigned int best_idx[256];
390 	unsigned int *markers;
391 	char buf[KSYM_NAME_LEN];
392 
393 	printf("#include <asm/bitsperlong.h>\n");
394 	printf("#if BITS_PER_LONG == 64\n");
395 	printf("#define PTR .quad\n");
396 	printf("#define ALGN .balign 8\n");
397 	printf("#else\n");
398 	printf("#define PTR .long\n");
399 	printf("#define ALGN .balign 4\n");
400 	printf("#endif\n");
401 
402 	printf("\t.section .rodata, \"a\"\n");
403 
404 	output_label("kallsyms_num_syms");
405 	printf("\t.long\t%u\n", table_cnt);
406 	printf("\n");
407 
408 	/* table of offset markers, that give the offset in the compressed stream
409 	 * every 256 symbols */
410 	markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256));
411 	if (!markers) {
412 		fprintf(stderr, "kallsyms failure: "
413 			"unable to allocate required memory\n");
414 		exit(EXIT_FAILURE);
415 	}
416 
417 	output_label("kallsyms_names");
418 	off = 0;
419 	for (i = 0; i < table_cnt; i++) {
420 		if ((i & 0xFF) == 0)
421 			markers[i >> 8] = off;
422 		table[i]->seq = i;
423 
424 		/* There cannot be any symbol of length zero. */
425 		if (table[i]->len == 0) {
426 			fprintf(stderr, "kallsyms failure: "
427 				"unexpected zero symbol length\n");
428 			exit(EXIT_FAILURE);
429 		}
430 
431 		/* Only lengths that fit in up-to-two-byte ULEB128 are supported. */
432 		if (table[i]->len > 0x3FFF) {
433 			fprintf(stderr, "kallsyms failure: "
434 				"unexpected huge symbol length\n");
435 			exit(EXIT_FAILURE);
436 		}
437 
438 		/* Encode length with ULEB128. */
439 		if (table[i]->len <= 0x7F) {
440 			/* Most symbols use a single byte for the length. */
441 			printf("\t.byte 0x%02x", table[i]->len);
442 			off += table[i]->len + 1;
443 		} else {
444 			/* "Big" symbols use two bytes. */
445 			printf("\t.byte 0x%02x, 0x%02x",
446 				(table[i]->len & 0x7F) | 0x80,
447 				(table[i]->len >> 7) & 0x7F);
448 			off += table[i]->len + 2;
449 		}
450 		for (k = 0; k < table[i]->len; k++)
451 			printf(", 0x%02x", table[i]->sym[k]);
452 		printf("\n");
453 	}
454 	printf("\n");
455 
456 	/*
457 	 * Now that we wrote out the compressed symbol names, restore the
458 	 * original names, which are needed in some of the later steps.
459 	 */
460 	for (i = 0; i < table_cnt; i++) {
461 		expand_symbol(table[i]->sym, table[i]->len, buf);
462 		strcpy((char *)table[i]->sym, buf);
463 	}
464 
465 	output_label("kallsyms_markers");
466 	for (i = 0; i < ((table_cnt + 255) >> 8); i++)
467 		printf("\t.long\t%u\n", markers[i]);
468 	printf("\n");
469 
470 	free(markers);
471 
472 	output_label("kallsyms_token_table");
473 	off = 0;
474 	for (i = 0; i < 256; i++) {
475 		best_idx[i] = off;
476 		expand_symbol(best_table[i], best_table_len[i], buf);
477 		printf("\t.asciz\t\"%s\"\n", buf);
478 		off += strlen(buf) + 1;
479 	}
480 	printf("\n");
481 
482 	output_label("kallsyms_token_index");
483 	for (i = 0; i < 256; i++)
484 		printf("\t.short\t%d\n", best_idx[i]);
485 	printf("\n");
486 
487 	if (!base_relative)
488 		output_label("kallsyms_addresses");
489 	else
490 		output_label("kallsyms_offsets");
491 
492 	for (i = 0; i < table_cnt; i++) {
493 		if (base_relative) {
494 			/*
495 			 * Use the offset relative to the lowest value
496 			 * encountered of all relative symbols, and emit
497 			 * non-relocatable fixed offsets that will be fixed
498 			 * up at runtime.
499 			 */
500 
501 			long long offset;
502 			int overflow;
503 
504 			if (!absolute_percpu) {
505 				offset = table[i]->addr - relative_base;
506 				overflow = (offset < 0 || offset > UINT_MAX);
507 			} else if (symbol_absolute(table[i])) {
508 				offset = table[i]->addr;
509 				overflow = (offset < 0 || offset > INT_MAX);
510 			} else {
511 				offset = relative_base - table[i]->addr - 1;
512 				overflow = (offset < INT_MIN || offset >= 0);
513 			}
514 			if (overflow) {
515 				fprintf(stderr, "kallsyms failure: "
516 					"%s symbol value %#llx out of range in relative mode\n",
517 					symbol_absolute(table[i]) ? "absolute" : "relative",
518 					table[i]->addr);
519 				exit(EXIT_FAILURE);
520 			}
521 			printf("\t.long\t%#x	/* %s */\n", (int)offset, table[i]->sym);
522 		} else if (!symbol_absolute(table[i])) {
523 			output_address(table[i]->addr);
524 		} else {
525 			printf("\tPTR\t%#llx\n", table[i]->addr);
526 		}
527 	}
528 	printf("\n");
529 
530 	if (base_relative) {
531 		output_label("kallsyms_relative_base");
532 		output_address(relative_base);
533 		printf("\n");
534 	}
535 
536 	if (lto_clang)
537 		for (i = 0; i < table_cnt; i++)
538 			cleanup_symbol_name((char *)table[i]->sym);
539 
540 	sort_symbols_by_name();
541 	output_label("kallsyms_seqs_of_names");
542 	for (i = 0; i < table_cnt; i++)
543 		printf("\t.byte 0x%02x, 0x%02x, 0x%02x\n",
544 			(unsigned char)(table[i]->seq >> 16),
545 			(unsigned char)(table[i]->seq >> 8),
546 			(unsigned char)(table[i]->seq >> 0));
547 	printf("\n");
548 }
549 
550 
551 /* table lookup compression functions */
552 
553 /* count all the possible tokens in a symbol */
554 static void learn_symbol(const unsigned char *symbol, int len)
555 {
556 	int i;
557 
558 	for (i = 0; i < len - 1; i++)
559 		token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++;
560 }
561 
562 /* decrease the count for all the possible tokens in a symbol */
563 static void forget_symbol(const unsigned char *symbol, int len)
564 {
565 	int i;
566 
567 	for (i = 0; i < len - 1; i++)
568 		token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
569 }
570 
571 /* do the initial token count */
572 static void build_initial_token_table(void)
573 {
574 	unsigned int i;
575 
576 	for (i = 0; i < table_cnt; i++)
577 		learn_symbol(table[i]->sym, table[i]->len);
578 }
579 
580 static unsigned char *find_token(unsigned char *str, int len,
581 				 const unsigned char *token)
582 {
583 	int i;
584 
585 	for (i = 0; i < len - 1; i++) {
586 		if (str[i] == token[0] && str[i+1] == token[1])
587 			return &str[i];
588 	}
589 	return NULL;
590 }
591 
592 /* replace a given token in all the valid symbols. Use the sampled symbols
593  * to update the counts */
594 static void compress_symbols(const unsigned char *str, int idx)
595 {
596 	unsigned int i, len, size;
597 	unsigned char *p1, *p2;
598 
599 	for (i = 0; i < table_cnt; i++) {
600 
601 		len = table[i]->len;
602 		p1 = table[i]->sym;
603 
604 		/* find the token on the symbol */
605 		p2 = find_token(p1, len, str);
606 		if (!p2) continue;
607 
608 		/* decrease the counts for this symbol's tokens */
609 		forget_symbol(table[i]->sym, len);
610 
611 		size = len;
612 
613 		do {
614 			*p2 = idx;
615 			p2++;
616 			size -= (p2 - p1);
617 			memmove(p2, p2 + 1, size);
618 			p1 = p2;
619 			len--;
620 
621 			if (size < 2) break;
622 
623 			/* find the token on the symbol */
624 			p2 = find_token(p1, size, str);
625 
626 		} while (p2);
627 
628 		table[i]->len = len;
629 
630 		/* increase the counts for this symbol's new tokens */
631 		learn_symbol(table[i]->sym, len);
632 	}
633 }
634 
635 /* search the token with the maximum profit */
636 static int find_best_token(void)
637 {
638 	int i, best, bestprofit;
639 
640 	bestprofit=-10000;
641 	best = 0;
642 
643 	for (i = 0; i < 0x10000; i++) {
644 		if (token_profit[i] > bestprofit) {
645 			best = i;
646 			bestprofit = token_profit[i];
647 		}
648 	}
649 	return best;
650 }
651 
652 /* this is the core of the algorithm: calculate the "best" table */
653 static void optimize_result(void)
654 {
655 	int i, best;
656 
657 	/* using the '\0' symbol last allows compress_symbols to use standard
658 	 * fast string functions */
659 	for (i = 255; i >= 0; i--) {
660 
661 		/* if this table slot is empty (it is not used by an actual
662 		 * original char code */
663 		if (!best_table_len[i]) {
664 
665 			/* find the token with the best profit value */
666 			best = find_best_token();
667 			if (token_profit[best] == 0)
668 				break;
669 
670 			/* place it in the "best" table */
671 			best_table_len[i] = 2;
672 			best_table[i][0] = best & 0xFF;
673 			best_table[i][1] = (best >> 8) & 0xFF;
674 
675 			/* replace this token in all the valid symbols */
676 			compress_symbols(best_table[i], i);
677 		}
678 	}
679 }
680 
681 /* start by placing the symbols that are actually used on the table */
682 static void insert_real_symbols_in_table(void)
683 {
684 	unsigned int i, j, c;
685 
686 	for (i = 0; i < table_cnt; i++) {
687 		for (j = 0; j < table[i]->len; j++) {
688 			c = table[i]->sym[j];
689 			best_table[c][0]=c;
690 			best_table_len[c]=1;
691 		}
692 	}
693 }
694 
695 static void optimize_token_table(void)
696 {
697 	build_initial_token_table();
698 
699 	insert_real_symbols_in_table();
700 
701 	optimize_result();
702 }
703 
704 /* guess for "linker script provide" symbol */
705 static int may_be_linker_script_provide_symbol(const struct sym_entry *se)
706 {
707 	const char *symbol = sym_name(se);
708 	int len = se->len - 1;
709 
710 	if (len < 8)
711 		return 0;
712 
713 	if (symbol[0] != '_' || symbol[1] != '_')
714 		return 0;
715 
716 	/* __start_XXXXX */
717 	if (!memcmp(symbol + 2, "start_", 6))
718 		return 1;
719 
720 	/* __stop_XXXXX */
721 	if (!memcmp(symbol + 2, "stop_", 5))
722 		return 1;
723 
724 	/* __end_XXXXX */
725 	if (!memcmp(symbol + 2, "end_", 4))
726 		return 1;
727 
728 	/* __XXXXX_start */
729 	if (!memcmp(symbol + len - 6, "_start", 6))
730 		return 1;
731 
732 	/* __XXXXX_end */
733 	if (!memcmp(symbol + len - 4, "_end", 4))
734 		return 1;
735 
736 	return 0;
737 }
738 
739 static int compare_symbols(const void *a, const void *b)
740 {
741 	const struct sym_entry *sa = *(const struct sym_entry **)a;
742 	const struct sym_entry *sb = *(const struct sym_entry **)b;
743 	int wa, wb;
744 
745 	/* sort by address first */
746 	if (sa->addr > sb->addr)
747 		return 1;
748 	if (sa->addr < sb->addr)
749 		return -1;
750 
751 	/* sort by "weakness" type */
752 	wa = (sa->sym[0] == 'w') || (sa->sym[0] == 'W');
753 	wb = (sb->sym[0] == 'w') || (sb->sym[0] == 'W');
754 	if (wa != wb)
755 		return wa - wb;
756 
757 	/* sort by "linker script provide" type */
758 	wa = may_be_linker_script_provide_symbol(sa);
759 	wb = may_be_linker_script_provide_symbol(sb);
760 	if (wa != wb)
761 		return wa - wb;
762 
763 	/* sort by the number of prefix underscores */
764 	wa = strspn(sym_name(sa), "_");
765 	wb = strspn(sym_name(sb), "_");
766 	if (wa != wb)
767 		return wa - wb;
768 
769 	/* sort by initial order, so that other symbols are left undisturbed */
770 	return sa->start_pos - sb->start_pos;
771 }
772 
773 static void sort_symbols(void)
774 {
775 	qsort(table, table_cnt, sizeof(table[0]), compare_symbols);
776 }
777 
778 static void make_percpus_absolute(void)
779 {
780 	unsigned int i;
781 
782 	for (i = 0; i < table_cnt; i++)
783 		if (symbol_in_range(table[i], &percpu_range, 1)) {
784 			/*
785 			 * Keep the 'A' override for percpu symbols to
786 			 * ensure consistent behavior compared to older
787 			 * versions of this tool.
788 			 */
789 			table[i]->sym[0] = 'A';
790 			table[i]->percpu_absolute = 1;
791 		}
792 }
793 
794 /* find the minimum non-absolute symbol address */
795 static void record_relative_base(void)
796 {
797 	unsigned int i;
798 
799 	for (i = 0; i < table_cnt; i++)
800 		if (!symbol_absolute(table[i])) {
801 			/*
802 			 * The table is sorted by address.
803 			 * Take the first non-absolute symbol value.
804 			 */
805 			relative_base = table[i]->addr;
806 			return;
807 		}
808 }
809 
810 int main(int argc, char **argv)
811 {
812 	while (1) {
813 		static const struct option long_options[] = {
814 			{"all-symbols",     no_argument, &all_symbols,     1},
815 			{"absolute-percpu", no_argument, &absolute_percpu, 1},
816 			{"base-relative",   no_argument, &base_relative,   1},
817 			{"lto-clang",       no_argument, &lto_clang,       1},
818 			{},
819 		};
820 
821 		int c = getopt_long(argc, argv, "", long_options, NULL);
822 
823 		if (c == -1)
824 			break;
825 		if (c != 0)
826 			usage();
827 	}
828 
829 	if (optind >= argc)
830 		usage();
831 
832 	read_map(argv[optind]);
833 	shrink_table();
834 	if (absolute_percpu)
835 		make_percpus_absolute();
836 	sort_symbols();
837 	if (base_relative)
838 		record_relative_base();
839 	optimize_token_table();
840 	write_src();
841 
842 	return 0;
843 }
844