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
14 static struct ksym syms[MAX_SYMS];
15 static int sym_cnt;
16
ksym_cmp(const void * p1,const void * p2)17 static int ksym_cmp(const void *p1, const void *p2)
18 {
19 return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
20 }
21
load_kallsyms(void)22 int 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
ksym_search(long key)48 struct 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
ksym_get_addr(const char * name)78 long 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 }
89