tools/perf/tests/vmlinux-kallsyms.c

   1 #include <linux/compiler.h>
   2 #include <linux/rbtree.h>
   3 #include <string.h>
   4 #include "map.h"
   5 #include "symbol.h"
   6 #include "util.h"
   7 #include "tests.h"
   8 #include "debug.h"
   9 #include "machine.h"
  10
  11 static int vmlinux_matches_kallsyms_filter(struct map *map __maybe_unused,
  12                                            struct symbol *sym)
  13 {
  14         bool *visited = symbol__priv(sym);
  15         *visited = true;
  16         return 0;
  17 }
  18
  19 #define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x))
  20
  21 int test__vmlinux_matches_kallsyms(int subtest __maybe_unused)
  22 {
  23         int err = -1;
  24         struct rb_node *nd;
  25         struct symbol *sym;
  26         struct map *kallsyms_map, *vmlinux_map, *map;
  27         struct machine kallsyms, vmlinux;
  28         enum map_type type = MAP__FUNCTION;
  29         struct maps *maps = &vmlinux.kmaps.maps[type];
  30         u64 mem_start, mem_end;
  31         bool header_printed;
  32
  33         /*
  34          * Step 1:
  35          *
  36          * Init the machines that will hold kernel, modules obtained from
  37          * both vmlinux + .ko files and from /proc/kallsyms split by modules.
  38          */
  39         machine__init(&kallsyms, "", HOST_KERNEL_ID);
  40         machine__init(&vmlinux, "", HOST_KERNEL_ID);
  41
  42         /*
  43          * Step 2:
  44          *
  45          * Create the kernel maps for kallsyms and the DSO where we will then
  46          * load /proc/kallsyms. Also create the modules maps from /proc/modules
  47          * and find the .ko files that match them in /lib/modules/`uname -r`/.
  48          */
  49         if (machine__create_kernel_maps(&kallsyms) < 0) {
  50                 pr_debug("machine__create_kernel_maps ");
  51                 goto out;
  52         }
  53
  54         /*
  55          * Step 3:
  56          *
  57          * Load and split /proc/kallsyms into multiple maps, one per module.
  58          * Do not use kcore, as this test was designed before kcore support
  59          * and has parts that only make sense if using the non-kcore code.
  60          * XXX: extend it to stress the kcorre code as well, hint: the list
  61          * of modules extracted from /proc/kcore, in its current form, can't
  62          * be compacted against the list of modules found in the "vmlinux"
  63          * code and with the one got from /proc/modules from the "kallsyms" code.
  64          */
  65         if (__machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type, true, NULL) <= 0) {
  66                 pr_debug("dso__load_kallsyms ");
  67                 goto out;
  68         }
  69
  70         /*
  71          * Step 4:
  72          *
  73          * kallsyms will be internally on demand sorted by name so that we can
  74          * find the reference relocation * symbol, i.e. the symbol we will use
  75          * to see if the running kernel was relocated by checking if it has the
  76          * same value in the vmlinux file we load.
  77          */
  78         kallsyms_map = machine__kernel_map(&kallsyms);
  79
  80         /*
  81          * Step 5:
  82          *
  83          * Now repeat step 2, this time for the vmlinux file we'll auto-locate.
  84          */
  85         if (machine__create_kernel_maps(&vmlinux) < 0) {
  86                 pr_debug("machine__create_kernel_maps ");
  87                 goto out;
  88         }
  89
  90         vmlinux_map = machine__kernel_map(&vmlinux);
  91
  92         /*
  93          * Step 6:
  94          *
  95          * Locate a vmlinux file in the vmlinux path that has a buildid that
  96          * matches the one of the running kernel.
  97          *
  98          * While doing that look if we find the ref reloc symbol, if we find it
  99          * we'll have its ref_reloc_symbol.unrelocated_addr and then
 100          * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
 101          * to fixup the symbols.
 102          */
 103         if (machine__load_vmlinux_path(&vmlinux, type,
 104                                        vmlinux_matches_kallsyms_filter) <= 0) {
 105                 pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
 106                 err = TEST_SKIP;
 107                 goto out;
 108         }
 109
 110         err = 0;
 111         /*
 112          * Step 7:
 113          *
 114          * Now look at the symbols in the vmlinux DSO and check if we find all of them
 115          * in the kallsyms dso. For the ones that are in both, check its names and
 116          * end addresses too.
 117          */
 118         for (nd = rb_first(&vmlinux_map->dso->symbols[type]); nd; nd = rb_next(nd)) {
 119                 struct symbol *pair, *first_pair;
 120
 121                 sym  = rb_entry(nd, struct symbol, rb_node);
 122
 123                 if (sym->start == sym->end)
 124                         continue;
 125
 126                 mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start);
 127                 mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end);
 128
 129                 first_pair = machine__find_kernel_symbol(&kallsyms, type,
 130                                                          mem_start, NULL, NULL);
 131                 pair = first_pair;
 132
 133                 if (pair && UM(pair->start) == mem_start) {
 134 next_pair:
 135                         if (strcmp(sym->name, pair->name) == 0) {
 136                                 /*
 137                                  * kallsyms don't have the symbol end, so we
 138                                  * set that by using the next symbol start - 1,
 139                                  * in some cases we get this up to a page
 140                                  * wrong, trace_kmalloc when I was developing
 141                                  * this code was one such example, 2106 bytes
 142                                  * off the real size. More than that and we
 143                                  * _really_ have a problem.
 144                                  */
 145                                 s64 skew = mem_end - UM(pair->end);
 146                                 if (llabs(skew) >= page_size)
 147                                         pr_debug("WARN: %#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
 148                                                  mem_start, sym->name, mem_end,
 149                                                  UM(pair->end));
 150
 151                                 /*
 152                                  * Do not count this as a failure, because we
 153                                  * could really find a case where it's not
 154                                  * possible to get proper function end from
 155                                  * kallsyms.
 156                                  */
 157                                 continue;
 158
 159                         } else {
 160                                 pair = machine__find_kernel_symbol_by_name(&kallsyms, type, sym->name, NULL, NULL);
 161                                 if (pair) {
 162                                         if (UM(pair->start) == mem_start)
 163                                                 goto next_pair;
 164
 165                                         pr_debug("ERR : %#" PRIx64 ": diff name v: %s k: %s\n",
 166                                                  mem_start, sym->name, pair->name);
 167                                 } else {
 168                                         pr_debug("ERR : %#" PRIx64 ": diff name v: %s k: %s\n",
 169                                                  mem_start, sym->name, first_pair->name);
 170                                 }
 171                         }
 172                 } else
 173                         pr_debug("ERR : %#" PRIx64 ": %s not on kallsyms\n",
 174                                  mem_start, sym->name);
 175
 176                 err = -1;
 177         }
 178
 179         if (!verbose)
 180                 goto out;
 181
 182         header_printed = false;
 183
 184         for (map = maps__first(maps); map; map = map__next(map)) {
 185                 struct map *
 186                 /*
 187                  * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while
 188                  * the kernel will have the path for the vmlinux file being used,
 189                  * so use the short name, less descriptive but the same ("[kernel]" in
 190                  * both cases.
 191                  */
 192                 pair = map_groups__find_by_name(&kallsyms.kmaps, type,
 193                                                 (map->dso->kernel ?
 194                                                         map->dso->short_name :
 195                                                         map->dso->name));
 196                 if (pair) {
 197                         pair->priv = 1;
 198                 } else {
 199                         if (!header_printed) {
 200                                 pr_info("WARN: Maps only in vmlinux:\n");
 201                                 header_printed = true;
 202                         }
 203                         map__fprintf(map, stderr);
 204                 }
 205         }
 206
 207         header_printed = false;
 208
 209         for (map = maps__first(maps); map; map = map__next(map)) {
 210                 struct map *pair;
 211
 212                 mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start);
 213                 mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end);
 214
 215                 pair = map_groups__find(&kallsyms.kmaps, type, mem_start);
 216                 if (pair == NULL || pair->priv)
 217                         continue;
 218
 219                 if (pair->start == mem_start) {
 220                         if (!header_printed) {
 221                                 pr_info("WARN: Maps in vmlinux with a different name in kallsyms:\n");
 222                                 header_printed = true;
 223                         }
 224
 225                         pr_info("WARN: %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
 226                                 map->start, map->end, map->pgoff, map->dso->name);
 227                         if (mem_end != pair->end)
 228                                 pr_info(":\nWARN: *%" PRIx64 "-%" PRIx64 " %" PRIx64,
 229                                         pair->start, pair->end, pair->pgoff);
 230                         pr_info(" %s\n", pair->dso->name);
 231                         pair->priv = 1;
 232                 }
 233         }
 234
 235         header_printed = false;
 236
 237         maps = &kallsyms.kmaps.maps[type];
 238
 239         for (map = maps__first(maps); map; map = map__next(map)) {
 240                 if (!map->priv) {
 241                         if (!header_printed) {
 242                                 pr_info("WARN: Maps only in kallsyms:\n");
 243                                 header_printed = true;
 244                         }
 245                         map__fprintf(map, stderr);
 246                 }
 247         }
 248 out:
 249         machine__exit(&kallsyms);
 250         machine__exit(&vmlinux);
 251         return err;
 252 }