]> nv-tegra.nvidia Code Review - linux-2.6.git/blob - tools/perf/util/symbol.c
perf tools: Fix faulty check
[linux-2.6.git] / tools / perf / util / symbol.c
1 #include "util.h"
2 #include "../perf.h"
3 #include "string.h"
4 #include "symbol.h"
5
6 #include <libelf.h>
7 #include <gelf.h>
8 #include <elf.h>
9 #include <bfd.h>
10
11 const char *sym_hist_filter;
12
13 #ifndef DMGL_PARAMS
14 #define DMGL_PARAMS      (1 << 0)       /* Include function args */
15 #define DMGL_ANSI        (1 << 1)       /* Include const, volatile, etc */
16 #endif
17
18 static struct symbol *symbol__new(u64 start, u64 len,
19                                   const char *name, unsigned int priv_size,
20                                   u64 obj_start, int verbose)
21 {
22         size_t namelen = strlen(name) + 1;
23         struct symbol *self = calloc(1, priv_size + sizeof(*self) + namelen);
24
25         if (!self)
26                 return NULL;
27
28         if (verbose >= 2)
29                 printf("new symbol: %016Lx [%08lx]: %s, hist: %p, obj_start: %p\n",
30                         (u64)start, (unsigned long)len, name, self->hist, (void *)(unsigned long)obj_start);
31
32         self->obj_start= obj_start;
33         self->hist = NULL;
34         self->hist_sum = 0;
35
36         if (sym_hist_filter && !strcmp(name, sym_hist_filter))
37                 self->hist = calloc(sizeof(u64), len);
38
39         if (priv_size) {
40                 memset(self, 0, priv_size);
41                 self = ((void *)self) + priv_size;
42         }
43         self->start = start;
44         self->end   = len ? start + len - 1 : start;
45         memcpy(self->name, name, namelen);
46
47         return self;
48 }
49
50 static void symbol__delete(struct symbol *self, unsigned int priv_size)
51 {
52         free(((void *)self) - priv_size);
53 }
54
55 static size_t symbol__fprintf(struct symbol *self, FILE *fp)
56 {
57         if (!self->module)
58                 return fprintf(fp, " %llx-%llx %s\n",
59                        self->start, self->end, self->name);
60         else
61                 return fprintf(fp, " %llx-%llx %s \t[%s]\n",
62                        self->start, self->end, self->name, self->module->name);
63 }
64
65 struct dso *dso__new(const char *name, unsigned int sym_priv_size)
66 {
67         struct dso *self = malloc(sizeof(*self) + strlen(name) + 1);
68
69         if (self != NULL) {
70                 strcpy(self->name, name);
71                 self->syms = RB_ROOT;
72                 self->sym_priv_size = sym_priv_size;
73                 self->find_symbol = dso__find_symbol;
74                 self->slen_calculated = 0;
75         }
76
77         return self;
78 }
79
80 static void dso__delete_symbols(struct dso *self)
81 {
82         struct symbol *pos;
83         struct rb_node *next = rb_first(&self->syms);
84
85         while (next) {
86                 pos = rb_entry(next, struct symbol, rb_node);
87                 next = rb_next(&pos->rb_node);
88                 rb_erase(&pos->rb_node, &self->syms);
89                 symbol__delete(pos, self->sym_priv_size);
90         }
91 }
92
93 void dso__delete(struct dso *self)
94 {
95         dso__delete_symbols(self);
96         free(self);
97 }
98
99 static void dso__insert_symbol(struct dso *self, struct symbol *sym)
100 {
101         struct rb_node **p = &self->syms.rb_node;
102         struct rb_node *parent = NULL;
103         const u64 ip = sym->start;
104         struct symbol *s;
105
106         while (*p != NULL) {
107                 parent = *p;
108                 s = rb_entry(parent, struct symbol, rb_node);
109                 if (ip < s->start)
110                         p = &(*p)->rb_left;
111                 else
112                         p = &(*p)->rb_right;
113         }
114         rb_link_node(&sym->rb_node, parent, p);
115         rb_insert_color(&sym->rb_node, &self->syms);
116 }
117
118 struct symbol *dso__find_symbol(struct dso *self, u64 ip)
119 {
120         struct rb_node *n;
121
122         if (self == NULL)
123                 return NULL;
124
125         n = self->syms.rb_node;
126
127         while (n) {
128                 struct symbol *s = rb_entry(n, struct symbol, rb_node);
129
130                 if (ip < s->start)
131                         n = n->rb_left;
132                 else if (ip > s->end)
133                         n = n->rb_right;
134                 else
135                         return s;
136         }
137
138         return NULL;
139 }
140
141 size_t dso__fprintf(struct dso *self, FILE *fp)
142 {
143         size_t ret = fprintf(fp, "dso: %s\n", self->name);
144
145         struct rb_node *nd;
146         for (nd = rb_first(&self->syms); nd; nd = rb_next(nd)) {
147                 struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
148                 ret += symbol__fprintf(pos, fp);
149         }
150
151         return ret;
152 }
153
154 static int dso__load_kallsyms(struct dso *self, symbol_filter_t filter, int verbose)
155 {
156         struct rb_node *nd, *prevnd;
157         char *line = NULL;
158         size_t n;
159         FILE *file = fopen("/proc/kallsyms", "r");
160         int count = 0;
161
162         if (file == NULL)
163                 goto out_failure;
164
165         while (!feof(file)) {
166                 u64 start;
167                 struct symbol *sym;
168                 int line_len, len;
169                 char symbol_type;
170
171                 line_len = getline(&line, &n, file);
172                 if (line_len < 0)
173                         break;
174
175                 if (!line)
176                         goto out_failure;
177
178                 line[--line_len] = '\0'; /* \n */
179
180                 len = hex2u64(line, &start);
181
182                 len++;
183                 if (len + 2 >= line_len)
184                         continue;
185
186                 symbol_type = toupper(line[len]);
187                 /*
188                  * We're interested only in code ('T'ext)
189                  */
190                 if (symbol_type != 'T' && symbol_type != 'W')
191                         continue;
192                 /*
193                  * Well fix up the end later, when we have all sorted.
194                  */
195                 sym = symbol__new(start, 0xdead, line + len + 2,
196                                   self->sym_priv_size, 0, verbose);
197
198                 if (sym == NULL)
199                         goto out_delete_line;
200
201                 if (filter && filter(self, sym))
202                         symbol__delete(sym, self->sym_priv_size);
203                 else {
204                         dso__insert_symbol(self, sym);
205                         count++;
206                 }
207         }
208
209         /*
210          * Now that we have all sorted out, just set the ->end of all
211          * symbols
212          */
213         prevnd = rb_first(&self->syms);
214
215         if (prevnd == NULL)
216                 goto out_delete_line;
217
218         for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
219                 struct symbol *prev = rb_entry(prevnd, struct symbol, rb_node),
220                               *curr = rb_entry(nd, struct symbol, rb_node);
221
222                 prev->end = curr->start - 1;
223                 prevnd = nd;
224         }
225
226         free(line);
227         fclose(file);
228
229         return count;
230
231 out_delete_line:
232         free(line);
233 out_failure:
234         return -1;
235 }
236
237 static int dso__load_perf_map(struct dso *self, symbol_filter_t filter, int verbose)
238 {
239         char *line = NULL;
240         size_t n;
241         FILE *file;
242         int nr_syms = 0;
243
244         file = fopen(self->name, "r");
245         if (file == NULL)
246                 goto out_failure;
247
248         while (!feof(file)) {
249                 u64 start, size;
250                 struct symbol *sym;
251                 int line_len, len;
252
253                 line_len = getline(&line, &n, file);
254                 if (line_len < 0)
255                         break;
256
257                 if (!line)
258                         goto out_failure;
259
260                 line[--line_len] = '\0'; /* \n */
261
262                 len = hex2u64(line, &start);
263
264                 len++;
265                 if (len + 2 >= line_len)
266                         continue;
267
268                 len += hex2u64(line + len, &size);
269
270                 len++;
271                 if (len + 2 >= line_len)
272                         continue;
273
274                 sym = symbol__new(start, size, line + len,
275                                   self->sym_priv_size, start, verbose);
276
277                 if (sym == NULL)
278                         goto out_delete_line;
279
280                 if (filter && filter(self, sym))
281                         symbol__delete(sym, self->sym_priv_size);
282                 else {
283                         dso__insert_symbol(self, sym);
284                         nr_syms++;
285                 }
286         }
287
288         free(line);
289         fclose(file);
290
291         return nr_syms;
292
293 out_delete_line:
294         free(line);
295 out_failure:
296         return -1;
297 }
298
299 /**
300  * elf_symtab__for_each_symbol - iterate thru all the symbols
301  *
302  * @self: struct elf_symtab instance to iterate
303  * @index: uint32_t index
304  * @sym: GElf_Sym iterator
305  */
306 #define elf_symtab__for_each_symbol(syms, nr_syms, index, sym) \
307         for (index = 0, gelf_getsym(syms, index, &sym);\
308              index < nr_syms; \
309              index++, gelf_getsym(syms, index, &sym))
310
311 static inline uint8_t elf_sym__type(const GElf_Sym *sym)
312 {
313         return GELF_ST_TYPE(sym->st_info);
314 }
315
316 static inline int elf_sym__is_function(const GElf_Sym *sym)
317 {
318         return elf_sym__type(sym) == STT_FUNC &&
319                sym->st_name != 0 &&
320                sym->st_shndx != SHN_UNDEF &&
321                sym->st_size != 0;
322 }
323
324 static inline int elf_sym__is_label(const GElf_Sym *sym)
325 {
326         return elf_sym__type(sym) == STT_NOTYPE &&
327                 sym->st_name != 0 &&
328                 sym->st_shndx != SHN_UNDEF &&
329                 sym->st_shndx != SHN_ABS;
330 }
331
332 static inline const char *elf_sec__name(const GElf_Shdr *shdr,
333                                         const Elf_Data *secstrs)
334 {
335         return secstrs->d_buf + shdr->sh_name;
336 }
337
338 static inline int elf_sec__is_text(const GElf_Shdr *shdr,
339                                         const Elf_Data *secstrs)
340 {
341         return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
342 }
343
344 static inline const char *elf_sym__name(const GElf_Sym *sym,
345                                         const Elf_Data *symstrs)
346 {
347         return symstrs->d_buf + sym->st_name;
348 }
349
350 static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
351                                     GElf_Shdr *shp, const char *name,
352                                     size_t *index)
353 {
354         Elf_Scn *sec = NULL;
355         size_t cnt = 1;
356
357         while ((sec = elf_nextscn(elf, sec)) != NULL) {
358                 char *str;
359
360                 gelf_getshdr(sec, shp);
361                 str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
362                 if (!strcmp(name, str)) {
363                         if (index)
364                                 *index = cnt;
365                         break;
366                 }
367                 ++cnt;
368         }
369
370         return sec;
371 }
372
373 #define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
374         for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
375              idx < nr_entries; \
376              ++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
377
378 #define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
379         for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
380              idx < nr_entries; \
381              ++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
382
383 /*
384  * We need to check if we have a .dynsym, so that we can handle the
385  * .plt, synthesizing its symbols, that aren't on the symtabs (be it
386  * .dynsym or .symtab).
387  * And always look at the original dso, not at debuginfo packages, that
388  * have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
389  */
390 static int dso__synthesize_plt_symbols(struct  dso *self, int verbose)
391 {
392         uint32_t nr_rel_entries, idx;
393         GElf_Sym sym;
394         u64 plt_offset;
395         GElf_Shdr shdr_plt;
396         struct symbol *f;
397         GElf_Shdr shdr_rel_plt, shdr_dynsym;
398         Elf_Data *reldata, *syms, *symstrs;
399         Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
400         size_t dynsym_idx;
401         GElf_Ehdr ehdr;
402         char sympltname[1024];
403         Elf *elf;
404         int nr = 0, symidx, fd, err = 0;
405
406         fd = open(self->name, O_RDONLY);
407         if (fd < 0)
408                 goto out;
409
410         elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
411         if (elf == NULL)
412                 goto out_close;
413
414         if (gelf_getehdr(elf, &ehdr) == NULL)
415                 goto out_elf_end;
416
417         scn_dynsym = elf_section_by_name(elf, &ehdr, &shdr_dynsym,
418                                          ".dynsym", &dynsym_idx);
419         if (scn_dynsym == NULL)
420                 goto out_elf_end;
421
422         scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
423                                           ".rela.plt", NULL);
424         if (scn_plt_rel == NULL) {
425                 scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
426                                                   ".rel.plt", NULL);
427                 if (scn_plt_rel == NULL)
428                         goto out_elf_end;
429         }
430
431         err = -1;
432
433         if (shdr_rel_plt.sh_link != dynsym_idx)
434                 goto out_elf_end;
435
436         if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
437                 goto out_elf_end;
438
439         /*
440          * Fetch the relocation section to find the indexes to the GOT
441          * and the symbols in the .dynsym they refer to.
442          */
443         reldata = elf_getdata(scn_plt_rel, NULL);
444         if (reldata == NULL)
445                 goto out_elf_end;
446
447         syms = elf_getdata(scn_dynsym, NULL);
448         if (syms == NULL)
449                 goto out_elf_end;
450
451         scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
452         if (scn_symstrs == NULL)
453                 goto out_elf_end;
454
455         symstrs = elf_getdata(scn_symstrs, NULL);
456         if (symstrs == NULL)
457                 goto out_elf_end;
458
459         nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
460         plt_offset = shdr_plt.sh_offset;
461
462         if (shdr_rel_plt.sh_type == SHT_RELA) {
463                 GElf_Rela pos_mem, *pos;
464
465                 elf_section__for_each_rela(reldata, pos, pos_mem, idx,
466                                            nr_rel_entries) {
467                         symidx = GELF_R_SYM(pos->r_info);
468                         plt_offset += shdr_plt.sh_entsize;
469                         gelf_getsym(syms, symidx, &sym);
470                         snprintf(sympltname, sizeof(sympltname),
471                                  "%s@plt", elf_sym__name(&sym, symstrs));
472
473                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
474                                         sympltname, self->sym_priv_size, 0, verbose);
475                         if (!f)
476                                 goto out_elf_end;
477
478                         dso__insert_symbol(self, f);
479                         ++nr;
480                 }
481         } else if (shdr_rel_plt.sh_type == SHT_REL) {
482                 GElf_Rel pos_mem, *pos;
483                 elf_section__for_each_rel(reldata, pos, pos_mem, idx,
484                                           nr_rel_entries) {
485                         symidx = GELF_R_SYM(pos->r_info);
486                         plt_offset += shdr_plt.sh_entsize;
487                         gelf_getsym(syms, symidx, &sym);
488                         snprintf(sympltname, sizeof(sympltname),
489                                  "%s@plt", elf_sym__name(&sym, symstrs));
490
491                         f = symbol__new(plt_offset, shdr_plt.sh_entsize,
492                                         sympltname, self->sym_priv_size, 0, verbose);
493                         if (!f)
494                                 goto out_elf_end;
495
496                         dso__insert_symbol(self, f);
497                         ++nr;
498                 }
499         }
500
501         err = 0;
502 out_elf_end:
503         elf_end(elf);
504 out_close:
505         close(fd);
506
507         if (err == 0)
508                 return nr;
509 out:
510         fprintf(stderr, "%s: problems reading %s PLT info.\n",
511                 __func__, self->name);
512         return 0;
513 }
514
515 static int dso__load_sym(struct dso *self, int fd, const char *name,
516                          symbol_filter_t filter, int verbose, struct module *mod)
517 {
518         Elf_Data *symstrs, *secstrs;
519         uint32_t nr_syms;
520         int err = -1;
521         uint32_t index;
522         GElf_Ehdr ehdr;
523         GElf_Shdr shdr;
524         Elf_Data *syms;
525         GElf_Sym sym;
526         Elf_Scn *sec, *sec_strndx;
527         Elf *elf;
528         int nr = 0, kernel = !strcmp("[kernel]", self->name);
529
530         elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
531         if (elf == NULL) {
532                 if (verbose)
533                         fprintf(stderr, "%s: cannot read %s ELF file.\n",
534                                 __func__, name);
535                 goto out_close;
536         }
537
538         if (gelf_getehdr(elf, &ehdr) == NULL) {
539                 if (verbose)
540                         fprintf(stderr, "%s: cannot get elf header.\n", __func__);
541                 goto out_elf_end;
542         }
543
544         sec = elf_section_by_name(elf, &ehdr, &shdr, ".symtab", NULL);
545         if (sec == NULL) {
546                 sec = elf_section_by_name(elf, &ehdr, &shdr, ".dynsym", NULL);
547                 if (sec == NULL)
548                         goto out_elf_end;
549         }
550
551         syms = elf_getdata(sec, NULL);
552         if (syms == NULL)
553                 goto out_elf_end;
554
555         sec = elf_getscn(elf, shdr.sh_link);
556         if (sec == NULL)
557                 goto out_elf_end;
558
559         symstrs = elf_getdata(sec, NULL);
560         if (symstrs == NULL)
561                 goto out_elf_end;
562
563         sec_strndx = elf_getscn(elf, ehdr.e_shstrndx);
564         if (sec_strndx == NULL)
565                 goto out_elf_end;
566
567         secstrs = elf_getdata(sec_strndx, NULL);
568         if (secstrs == NULL)
569                 goto out_elf_end;
570
571         nr_syms = shdr.sh_size / shdr.sh_entsize;
572
573         memset(&sym, 0, sizeof(sym));
574         if (!kernel) {
575                 self->adjust_symbols = (ehdr.e_type == ET_EXEC ||
576                                 elf_section_by_name(elf, &ehdr, &shdr,
577                                                      ".gnu.prelink_undo",
578                                                      NULL) != NULL);
579         } else self->adjust_symbols = 0;
580
581         elf_symtab__for_each_symbol(syms, nr_syms, index, sym) {
582                 struct symbol *f;
583                 const char *name;
584                 char *demangled;
585                 u64 obj_start;
586                 struct section *section = NULL;
587                 int is_label = elf_sym__is_label(&sym);
588                 const char *section_name;
589
590                 if (!is_label && !elf_sym__is_function(&sym))
591                         continue;
592
593                 sec = elf_getscn(elf, sym.st_shndx);
594                 if (!sec)
595                         goto out_elf_end;
596
597                 gelf_getshdr(sec, &shdr);
598
599                 if (is_label && !elf_sec__is_text(&shdr, secstrs))
600                         continue;
601
602                 section_name = elf_sec__name(&shdr, secstrs);
603                 obj_start = sym.st_value;
604
605                 if (self->adjust_symbols) {
606                         if (verbose >= 2)
607                                 printf("adjusting symbol: st_value: %Lx sh_addr: %Lx sh_offset: %Lx\n",
608                                         (u64)sym.st_value, (u64)shdr.sh_addr, (u64)shdr.sh_offset);
609
610                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
611                 }
612
613                 if (mod) {
614                         section = mod->sections->find_section(mod->sections, section_name);
615                         if (section)
616                                 sym.st_value += section->vma;
617                         else {
618                                 fprintf(stderr, "dso__load_sym() module %s lookup of %s failed\n",
619                                         mod->name, section_name);
620                                 goto out_elf_end;
621                         }
622                 }
623                 /*
624                  * We need to figure out if the object was created from C++ sources
625                  * DWARF DW_compile_unit has this, but we don't always have access
626                  * to it...
627                  */
628                 name = elf_sym__name(&sym, symstrs);
629                 demangled = bfd_demangle(NULL, name, DMGL_PARAMS | DMGL_ANSI);
630                 if (demangled != NULL)
631                         name = demangled;
632
633                 f = symbol__new(sym.st_value, sym.st_size, name,
634                                 self->sym_priv_size, obj_start, verbose);
635                 free(demangled);
636                 if (!f)
637                         goto out_elf_end;
638
639                 if (filter && filter(self, f))
640                         symbol__delete(f, self->sym_priv_size);
641                 else {
642                         f->module = mod;
643                         dso__insert_symbol(self, f);
644                         nr++;
645                 }
646         }
647
648         err = nr;
649 out_elf_end:
650         elf_end(elf);
651 out_close:
652         return err;
653 }
654
655 int dso__load(struct dso *self, symbol_filter_t filter, int verbose)
656 {
657         int size = strlen(self->name) + sizeof("/usr/lib/debug%s.debug");
658         char *name = malloc(size);
659         int variant = 0;
660         int ret = -1;
661         int fd;
662
663         if (!name)
664                 return -1;
665
666         self->adjust_symbols = 0;
667
668         if (strncmp(self->name, "/tmp/perf-", 10) == 0)
669                 return dso__load_perf_map(self, filter, verbose);
670
671 more:
672         do {
673                 switch (variant) {
674                 case 0: /* Fedora */
675                         snprintf(name, size, "/usr/lib/debug%s.debug", self->name);
676                         break;
677                 case 1: /* Ubuntu */
678                         snprintf(name, size, "/usr/lib/debug%s", self->name);
679                         break;
680                 case 2: /* Sane people */
681                         snprintf(name, size, "%s", self->name);
682                         break;
683
684                 default:
685                         goto out;
686                 }
687                 variant++;
688
689                 fd = open(name, O_RDONLY);
690         } while (fd < 0);
691
692         ret = dso__load_sym(self, fd, name, filter, verbose, NULL);
693         close(fd);
694
695         /*
696          * Some people seem to have debuginfo files _WITHOUT_ debug info!?!?
697          */
698         if (!ret)
699                 goto more;
700
701         if (ret > 0) {
702                 int nr_plt = dso__synthesize_plt_symbols(self, verbose);
703                 if (nr_plt > 0)
704                         ret += nr_plt;
705         }
706 out:
707         free(name);
708         return ret;
709 }
710
711 static int dso__load_module(struct dso *self, struct mod_dso *mods, const char *name,
712                              symbol_filter_t filter, int verbose)
713 {
714         struct module *mod = mod_dso__find_module(mods, name);
715         int err = 0, fd;
716
717         if (mod == NULL || !mod->active)
718                 return err;
719
720         fd = open(mod->path, O_RDONLY);
721
722         if (fd < 0)
723                 return err;
724
725         err = dso__load_sym(self, fd, name, filter, verbose, mod);
726         close(fd);
727
728         return err;
729 }
730
731 int dso__load_modules(struct dso *self, symbol_filter_t filter, int verbose)
732 {
733         struct mod_dso *mods = mod_dso__new_dso("modules");
734         struct module *pos;
735         struct rb_node *next;
736         int err;
737
738         err = mod_dso__load_modules(mods);
739
740         if (err <= 0)
741                 return err;
742
743         /*
744          * Iterate over modules, and load active symbols.
745          */
746         next = rb_first(&mods->mods);
747         while (next) {
748                 pos = rb_entry(next, struct module, rb_node);
749                 err = dso__load_module(self, mods, pos->name, filter, verbose);
750
751                 if (err < 0)
752                         break;
753
754                 next = rb_next(&pos->rb_node);
755         }
756
757         if (err < 0) {
758                 mod_dso__delete_modules(mods);
759                 mod_dso__delete_self(mods);
760         }
761
762         return err;
763 }
764
765 static inline void dso__fill_symbol_holes(struct dso *self)
766 {
767         struct symbol *prev = NULL;
768         struct rb_node *nd;
769
770         for (nd = rb_last(&self->syms); nd; nd = rb_prev(nd)) {
771                 struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
772
773                 if (prev) {
774                         u64 hole = 0;
775                         int alias = pos->start == prev->start;
776
777                         if (!alias)
778                                 hole = prev->start - pos->end - 1;
779
780                         if (hole || alias) {
781                                 if (alias)
782                                         pos->end = prev->end;
783                                 else if (hole)
784                                         pos->end = prev->start - 1;
785                         }
786                 }
787                 prev = pos;
788         }
789 }
790
791 static int dso__load_vmlinux(struct dso *self, const char *vmlinux,
792                              symbol_filter_t filter, int verbose)
793 {
794         int err, fd = open(vmlinux, O_RDONLY);
795
796         if (fd < 0)
797                 return -1;
798
799         err = dso__load_sym(self, fd, vmlinux, filter, verbose, NULL);
800
801         if (err > 0)
802                 dso__fill_symbol_holes(self);
803
804         close(fd);
805
806         return err;
807 }
808
809 int dso__load_kernel(struct dso *self, const char *vmlinux,
810                      symbol_filter_t filter, int verbose, int modules)
811 {
812         int err = -1;
813
814         if (vmlinux) {
815                 err = dso__load_vmlinux(self, vmlinux, filter, verbose);
816                 if (err > 0 && modules)
817                         err = dso__load_modules(self, filter, verbose);
818         }
819
820         if (err <= 0)
821                 err = dso__load_kallsyms(self, filter, verbose);
822
823         return err;
824 }
825
826 void symbol__init(void)
827 {
828         elf_version(EV_CURRENT);
829 }