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