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