1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/types.h>
3 #include <linux/string.h>
4 #include <limits.h>
5 #include <stdlib.h>
6
7 #include <internal/lib.h> // page_size
8 #include "../../../util/machine.h"
9 #include "../../../util/map.h"
10 #include "../../../util/symbol.h"
11 #include <linux/ctype.h>
12
13 #include <symbol/kallsyms.h>
14
15 #if defined(__x86_64__)
16
17 struct extra_kernel_map_info {
18 int cnt;
19 int max_cnt;
20 struct extra_kernel_map *maps;
21 bool get_entry_trampolines;
22 u64 entry_trampoline;
23 };
24
25 static int add_extra_kernel_map(struct extra_kernel_map_info *mi, u64 start,
26 u64 end, u64 pgoff, const char *name)
27 {
28 if (mi->cnt >= mi->max_cnt) {
29 void *buf;
30 size_t sz;
31
32 mi->max_cnt = mi->max_cnt ? mi->max_cnt * 2 : 32;
33 sz = sizeof(struct extra_kernel_map) * mi->max_cnt;
34 buf = realloc(mi->maps, sz);
35 if (!buf)
36 return -1;
37 mi->maps = buf;
38 }
39
40 mi->maps[mi->cnt].start = start;
41 mi->maps[mi->cnt].end = end;
42 mi->maps[mi->cnt].pgoff = pgoff;
43 strlcpy(mi->maps[mi->cnt].name, name, KMAP_NAME_LEN);
44
45 mi->cnt += 1;
46
47 return 0;
48 }
49
50 static int find_extra_kernel_maps(void *arg, const char *name, char type,
51 u64 start)
52 {
53 struct extra_kernel_map_info *mi = arg;
54
55 if (!mi->entry_trampoline && kallsyms2elf_binding(type) == STB_GLOBAL &&
56 !strcmp(name, "_entry_trampoline")) {
57 mi->entry_trampoline = start;
58 return 0;
59 }
60
61 if (is_entry_trampoline(name)) {
62 u64 end = start + page_size;
63
64 return add_extra_kernel_map(mi, start, end, 0, name);
65 }
66
67 return 0;
68 }
69
70 int machine__create_extra_kernel_maps(struct machine *machine,
71 struct dso *kernel)
72 {
73 struct extra_kernel_map_info mi = { .cnt = 0, };
74 char filename[PATH_MAX];
75 int ret;
76 int i;
77
78 machine__get_kallsyms_filename(machine, filename, PATH_MAX);
79
80 if (symbol__restricted_filename(filename, "/proc/kallsyms"))
81 return 0;
82
83 ret = kallsyms__parse(filename, &mi, find_extra_kernel_maps);
84 if (ret)
85 goto out_free;
86
87 if (!mi.entry_trampoline)
88 goto out_free;
89
90 for (i = 0; i < mi.cnt; i++) {
91 struct extra_kernel_map *xm = &mi.maps[i];
92
93 xm->pgoff = mi.entry_trampoline;
94 ret = machine__create_extra_kernel_map(machine, kernel, xm);
95 if (ret)
96 goto out_free;
97 }
98
99 machine->trampolines_mapped = mi.cnt;
100 out_free:
101 free(mi.maps);
102 return ret;
103 }
104
105 #endif
106
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