diff options
Diffstat (limited to 'tapsets.cxx')
| -rw-r--r-- | tapsets.cxx | 59 |
1 files changed, 50 insertions, 9 deletions
diff --git a/tapsets.cxx b/tapsets.cxx index 96999d26..8203c568 100644 --- a/tapsets.cxx +++ b/tapsets.cxx @@ -472,7 +472,7 @@ struct func_info { func_info() - : decl_file(NULL), decl_line(-1), addr(0), prologue_end(0) + : decl_file(NULL), decl_line(-1), addr(0), prologue_end(0), weak(false) { memset(&die, 0, sizeof(die)); } @@ -482,6 +482,7 @@ func_info Dwarf_Die die; Dwarf_Addr addr; Dwarf_Addr prologue_end; + bool weak; }; struct @@ -560,12 +561,14 @@ symbol_table map<string, func_info*> map_by_name; vector<func_info*> list_by_addr; - void add_symbol(const char *name, Dwarf_Addr addr, Dwarf_Addr *high_addr); + void add_symbol(const char *name, bool weak, Dwarf_Addr addr, + Dwarf_Addr *high_addr); enum info_status read_symbols(FILE *f, const string& path); enum info_status read_from_elf_file(const string& path); enum info_status read_from_text_file(const string& path); enum info_status get_from_elf(); void mark_dwarf_redundancies(dwflpp *dw); + void purge_syscall_stubs(); func_info *lookup_symbol(const string& name); Dwarf_Addr lookup_symbol_address(const string& name); func_info *get_func_containing_address(Dwarf_Addr addr); @@ -4696,12 +4699,18 @@ symbol_table::~symbol_table() } void -symbol_table::add_symbol(const char *name, Dwarf_Addr addr, - Dwarf_Addr *high_addr) +symbol_table::add_symbol(const char *name, bool weak, Dwarf_Addr addr, + Dwarf_Addr *high_addr) { +#ifdef __powerpc__ + // Map ".sys_foo" to "sys_foo". + if (name[0] == '.') + name++; +#endif func_info *fi = new func_info(); fi->addr = addr; fi->name = name; + fi->weak = weak; map_by_name[fi->name] = fi; // TODO: Use a multimap in case there are multiple static // functions with the same name? @@ -4752,8 +4761,8 @@ symbol_table::read_symbols(FILE *f, const string& path) free(mod); goto done; } - if (type == 'T' || type == 't') - add_symbol(name, (Dwarf_Addr) addr, &high_addr); + if (type == 'T' || type == 't' || type == 'W') + add_symbol(name, (type == 'W'), (Dwarf_Addr) addr, &high_addr); free(name); } @@ -4818,9 +4827,11 @@ symbol_table::get_from_elf() for (int i = 1; i < syments; ++i) { GElf_Sym sym; - const char *name = dwfl_module_getsym(mod, i, &sym, NULL); - if (name && GELF_ST_TYPE(sym.st_info) == STT_FUNC) - add_symbol(name, sym.st_value, &high_addr); + GElf_Word section; + const char *name = dwfl_module_getsym(mod, i, &sym, §ion); + if (name && GELF_ST_TYPE(sym.st_info) == STT_FUNC && section != SHN_UNDEF) + add_symbol(name, (GELF_ST_BIND(sym.st_info) == STB_WEAK), + sym.st_value, &high_addr); } return info_present; } @@ -4912,6 +4923,33 @@ symbol_table::lookup_symbol_address(const string& name) return 0; } +// This is the kernel symbol table. The kernel macro cond_syscall creates +// a weak symbol for each system call and maps it to sys_ni_syscall. +// For system calls not implemented elsewhere, this weak symbol shows up +// in the kernel symbol table. Following the precedent of dwarfful stap, +// we refuse to consider such symbols. Here we delete them from our +// symbol table. +// TODO: Consider generalizing this and/or making it part of blacklist +// processing. +void +symbol_table::purge_syscall_stubs() +{ + Dwarf_Addr stub_addr = lookup_symbol_address("sys_ni_syscall"); + if (stub_addr == 0) + return; + for (size_t i = 0; i < list_by_addr.size(); i++) + { + func_info *fi = list_by_addr.at(i); + if (fi->weak && fi->addr == stub_addr && fi->name != "sys_ni_syscall") + { + list_by_addr.erase(list_by_addr.begin()+i); + map_by_name.erase(fi->name); + delete fi; + i--; + } + } +} + void module_info::get_symtab(dwarf_query *q) { @@ -4967,6 +5005,9 @@ module_info::get_symtab(dwarf_query *q) // precedes the call to query_module_symtab(). So we should never read // a module's symbol table without first having tried to get its dwarf. sym_table->mark_dwarf_redundancies(&q->dw); + + if (name == TOK_KERNEL) + sym_table->purge_syscall_stubs(); } module_info::~module_info() |