tools/perf/arch/x86/util/machine.c

   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