1// SPDX-License-Identifier: GPL-2.0
 2#include <stdio.h>
 3#include <stdlib.h>
 4#include <string.h>
 5#include <assert.h>
 6#include <errno.h>
 7#include <poll.h>
 8#include <unistd.h>
 9#include <linux/perf_event.h>
10#include <sys/mman.h>
11#include "trace_helpers.h"
12
13#define MAX_SYMS 300000
14static struct ksym syms[MAX_SYMS];
15static int sym_cnt;
16
17static int ksym_cmp(const void *p1, const void *p2)
18{
19	return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
20}
21
22int load_kallsyms(void)
23{
24	FILE *f = fopen("/proc/kallsyms", "r");
25	char func[256], buf[256];
26	char symbol;
27	void *addr;
28	int i = 0;
29
30	if (!f)
31		return -ENOENT;
32
33	while (fgets(buf, sizeof(buf), f)) {
34		if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
35			break;
36		if (!addr)
37			continue;
38		syms[i].addr = (long) addr;
39		syms[i].name = strdup(func);
40		i++;
41	}
42	fclose(f);
43	sym_cnt = i;
44	qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp);
45	return 0;
46}
47
48struct ksym *ksym_search(long key)
49{
50	int start = 0, end = sym_cnt;
51	int result;
52
53	/* kallsyms not loaded. return NULL */
54	if (sym_cnt <= 0)
55		return NULL;
56
57	while (start < end) {
58		size_t mid = start + (end - start) / 2;
59
60		result = key - syms[mid].addr;
61		if (result < 0)
62			end = mid;
63		else if (result > 0)
64			start = mid + 1;
65		else
66			return &syms[mid];
67	}
68
69	if (start >= 1 && syms[start - 1].addr < key &&
70	    key < syms[start].addr)
71		/* valid ksym */
72		return &syms[start - 1];
73
74	/* out of range. return _stext */
75	return &syms[0];
76}
77
78long ksym_get_addr(const char *name)
79{
80	int i;
81
82	for (i = 0; i < sym_cnt; i++) {
83		if (strcmp(syms[i].name, name) == 0)
84			return syms[i].addr;
85	}
86
87	return 0;
88}