correlate_symbols() will always try to match full name first. If there is no match, try match only demangled_name.
In very rare cases, it is possible to have multiple foo.llvm.<hash> in the same kernel. Whenever there is ambiguity like this, fail the klp diff. Signed-off-by: Song Liu <[email protected]> --- tools/objtool/elf.c | 13 +++++++ tools/objtool/include/objtool/elf.h | 3 ++ tools/objtool/klp-diff.c | 57 +++++++++++++++++++++++++++++ 3 files changed, 73 insertions(+) diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index efb13ec0a89d..5ddbfa8f8701 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -323,6 +323,19 @@ struct symbol *find_global_symbol_by_name(const struct elf *elf, const char *nam return NULL; } +void iterate_global_symbol_by_demangled_name(const struct elf *elf, + const char *demangled_name, + void (*process)(struct symbol *sym, void *data), + void *data) +{ + struct symbol *sym; + + elf_hash_for_each_possible(symbol_name, sym, name_hash, str_hash(demangled_name)) { + if (!strcmp(sym->demangled_name, demangled_name) && !is_local_sym(sym)) + process(sym, data); + } +} + struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec, unsigned long offset, unsigned int len) { diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h index e12c516bd320..25573e5af76e 100644 --- a/tools/objtool/include/objtool/elf.h +++ b/tools/objtool/include/objtool/elf.h @@ -186,6 +186,9 @@ struct symbol *find_func_by_offset(struct section *sec, unsigned long offset); struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset); struct symbol *find_symbol_by_name(const struct elf *elf, const char *name); struct symbol *find_global_symbol_by_name(const struct elf *elf, const char *name); +void iterate_global_symbol_by_demangled_name(const struct elf *elf, const char *demangled_name, + void (*process)(struct symbol *sym, void *data), + void *data); struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset); int find_symbol_hole_containing(const struct section *sec, unsigned long offset); struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset); diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c index 57606bc3390a..92043da0ed0b 100644 --- a/tools/objtool/klp-diff.c +++ b/tools/objtool/klp-diff.c @@ -355,6 +355,46 @@ static bool dont_correlate(struct symbol *sym) strstarts(sym->name, "__initcall__"); } +struct process_demangled_name_data { + struct symbol *ret; + int count; +}; + +static void process_demangled_name(struct symbol *sym, void *d) +{ + struct process_demangled_name_data *data = d; + + if (sym->twin) + return; + + data->count++; + data->ret = sym; +} + +/* + * When there is no full name match, try match demangled_name. This would + * match original foo.llvm.123 to patched foo.llvm.456. + * + * Note that, in very rare cases, it is possible to have multiple + * foo.llvm.<hash> in the same kernel. When this happens, report error and + * fail the diff. + */ +static int find_global_symbol_by_demangled_name(struct elf *elf, struct symbol *sym, + struct symbol **out_sym) +{ + struct process_demangled_name_data data = {}; + + iterate_global_symbol_by_demangled_name(elf, sym->demangled_name, + process_demangled_name, + &data); + if (data.count > 1) { + ERROR("Multiple (%d) correlation candidates for %s", data.count, sym->name); + return -1; + } + *out_sym = data.ret; + return 0; +} + /* * For each symbol in the original kernel, find its corresponding "twin" in the * patched kernel. @@ -453,6 +493,23 @@ static int correlate_symbols(struct elfs *e) continue; sym2 = find_global_symbol_by_name(e->patched, sym1->name); + if (sym2 && !sym2->twin) { + sym1->twin = sym2; + sym2->twin = sym1; + } + } + + /* + * Correlate globals with demangled_name. + * A separate loop is needed because we want to finish all the + * full name correlations first. + */ + for_each_sym(e->orig, sym1) { + if (sym1->bind == STB_LOCAL || sym1->twin) + continue; + + if (find_global_symbol_by_demangled_name(e->patched, sym1, &sym2)) + return -1; if (sym2 && !sym2->twin) { sym1->twin = sym2; -- 2.47.3
