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
17struct 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
25static 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
50static 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
70int 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;
100out_free:
101	free(mi.maps);
102	return ret;
103}
104
105#endif
106