x86/util/machine.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <linux/types.h>
0003 #include <linux/string.h>
0004 #include <limits.h>
0005 #include <stdlib.h>
0006
0007 #include <internal/lib.h> // page_size
0008 #include "../../../util/machine.h"
0009 #include "../../../util/map.h"
0010 #include "../../../util/symbol.h"
0011 #include <linux/ctype.h>
0012
0013 #include <symbol/kallsyms.h>
0014
0015 #if defined(__x86_64__)
0016
0017 struct extra_kernel_map_info {
0018     int cnt;
0019     int max_cnt;
0020     struct extra_kernel_map *maps;
0021     bool get_entry_trampolines;
0022     u64 entry_trampoline;
0023 };
0024
0025 static int add_extra_kernel_map(struct extra_kernel_map_info *mi, u64 start,
0026                 u64 end, u64 pgoff, const char *name)
0027 {
0028     if (mi->cnt >= mi->max_cnt) {
0029         void *buf;
0030         size_t sz;
0031
0032         mi->max_cnt = mi->max_cnt ? mi->max_cnt * 2 : 32;
0033         sz = sizeof(struct extra_kernel_map) * mi->max_cnt;
0034         buf = realloc(mi->maps, sz);
0035         if (!buf)
0036             return -1;
0037         mi->maps = buf;
0038     }
0039
0040     mi->maps[mi->cnt].start = start;
0041     mi->maps[mi->cnt].end   = end;
0042     mi->maps[mi->cnt].pgoff = pgoff;
0043     strlcpy(mi->maps[mi->cnt].name, name, KMAP_NAME_LEN);
0044
0045     mi->cnt += 1;
0046
0047     return 0;
0048 }
0049
0050 static int find_extra_kernel_maps(void *arg, const char *name, char type,
0051                   u64 start)
0052 {
0053     struct extra_kernel_map_info *mi = arg;
0054
0055     if (!mi->entry_trampoline && kallsyms2elf_binding(type) == STB_GLOBAL &&
0056         !strcmp(name, "_entry_trampoline")) {
0057         mi->entry_trampoline = start;
0058         return 0;
0059     }
0060
0061     if (is_entry_trampoline(name)) {
0062         u64 end = start + page_size;
0063
0064         return add_extra_kernel_map(mi, start, end, 0, name);
0065     }
0066
0067     return 0;
0068 }
0069
0070 int machine__create_extra_kernel_maps(struct machine *machine,
0071                       struct dso *kernel)
0072 {
0073     struct extra_kernel_map_info mi = { .cnt = 0, };
0074     char filename[PATH_MAX];
0075     int ret;
0076     int i;
0077
0078     machine__get_kallsyms_filename(machine, filename, PATH_MAX);
0079
0080     if (symbol__restricted_filename(filename, "/proc/kallsyms"))
0081         return 0;
0082
0083     ret = kallsyms__parse(filename, &mi, find_extra_kernel_maps);
0084     if (ret)
0085         goto out_free;
0086
0087     if (!mi.entry_trampoline)
0088         goto out_free;
0089
0090     for (i = 0; i < mi.cnt; i++) {
0091         struct extra_kernel_map *xm = &mi.maps[i];
0092
0093         xm->pgoff = mi.entry_trampoline;
0094         ret = machine__create_extra_kernel_map(machine, kernel, xm);
0095         if (ret)
0096             goto out_free;
0097     }
0098
0099     machine->trampolines_mapped = mi.cnt;
0100 out_free:
0101     free(mi.maps);
0102     return ret;
0103 }
0104
0105 #endif