diff options
Diffstat (limited to 'tools/perf/util/symbol-elf.c')
| -rw-r--r-- | tools/perf/util/symbol-elf.c | 79 |
1 files changed, 76 insertions, 3 deletions
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 4b934ed3bf..0b91f813c4 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -23,6 +23,7 @@ #include <linux/ctype.h> #include <linux/kernel.h> #include <linux/zalloc.h> +#include <linux/string.h> #include <symbol/kallsyms.h> #include <internal/lib.h> @@ -1329,6 +1330,58 @@ out_close: return -1; } +static bool is_exe_text(int flags) +{ + return (flags & (SHF_ALLOC | SHF_EXECINSTR)) == (SHF_ALLOC | SHF_EXECINSTR); +} + +/* + * Some executable module sections like .noinstr.text might be laid out with + * .text so they can use the same mapping (memory address to file offset). + * Check if that is the case. Refer to kernel layout_sections(). Return the + * maximum offset. + */ +static u64 max_text_section(Elf *elf, GElf_Ehdr *ehdr) +{ + Elf_Scn *sec = NULL; + GElf_Shdr shdr; + u64 offs = 0; + + /* Doesn't work for some arch */ + if (ehdr->e_machine == EM_PARISC || + ehdr->e_machine == EM_ALPHA) + return 0; + + /* ELF is corrupted/truncated, avoid calling elf_strptr. */ + if (!elf_rawdata(elf_getscn(elf, ehdr->e_shstrndx), NULL)) + return 0; + + while ((sec = elf_nextscn(elf, sec)) != NULL) { + char *sec_name; + + if (!gelf_getshdr(sec, &shdr)) + break; + + if (!is_exe_text(shdr.sh_flags)) + continue; + + /* .init and .exit sections are not placed with .text */ + sec_name = elf_strptr(elf, ehdr->e_shstrndx, shdr.sh_name); + if (!sec_name || + strstarts(sec_name, ".init") || + strstarts(sec_name, ".exit")) + break; + + /* Must be next to previous, assumes .text is first */ + if (offs && PERF_ALIGN(offs, shdr.sh_addralign ?: 1) != shdr.sh_offset) + break; + + offs = shdr.sh_offset + shdr.sh_size; + } + + return offs; +} + /** * ref_reloc_sym_not_found - has kernel relocation symbol been found. * @kmap: kernel maps and relocation reference symbol @@ -1368,7 +1421,8 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map, struct maps *kmaps, struct kmap *kmap, struct dso **curr_dsop, struct map **curr_mapp, const char *section_name, - bool adjust_kernel_syms, bool kmodule, bool *remap_kernel) + bool adjust_kernel_syms, bool kmodule, bool *remap_kernel, + u64 max_text_sh_offset) { struct dso *curr_dso = *curr_dsop; struct map *curr_map; @@ -1424,6 +1478,17 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map, if (!kmap) return 0; + /* + * perf does not record module section addresses except for .text, but + * some sections can use the same mapping as .text. + */ + if (kmodule && adjust_kernel_syms && is_exe_text(shdr->sh_flags) && + shdr->sh_offset <= max_text_sh_offset) { + *curr_mapp = map; + *curr_dsop = dso; + return 0; + } + snprintf(dso_name, sizeof(dso_name), "%s%s", dso->short_name, section_name); curr_map = maps__find_by_name(kmaps, dso_name); @@ -1470,8 +1535,10 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map, dso__set_loaded(curr_dso); *curr_mapp = curr_map; *curr_dsop = curr_dso; - } else + } else { *curr_dsop = map__dso(curr_map); + map__put(curr_map); + } return 0; } @@ -1497,6 +1564,7 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss, Elf *elf; int nr = 0; bool remap_kernel = false, adjust_kernel_syms = false; + u64 max_text_sh_offset = 0; if (kmap && !kmaps) return -1; @@ -1584,6 +1652,10 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss, remap_kernel = true; adjust_kernel_syms = dso->adjust_symbols; } + + if (kmodule && adjust_kernel_syms) + max_text_sh_offset = max_text_section(runtime_ss->elf, &runtime_ss->ehdr); + elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) { struct symbol *f; const char *elf_name = elf_sym__name(&sym, symstrs); @@ -1673,7 +1745,8 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss, if (dso->kernel) { if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map, - section_name, adjust_kernel_syms, kmodule, &remap_kernel)) + section_name, adjust_kernel_syms, kmodule, + &remap_kernel, max_text_sh_offset)) goto out_elf_end; } else if ((used_opd && runtime_ss->adjust_symbols) || (!used_opd && syms_ss->adjust_symbols)) { |