diff options
Diffstat (limited to 'tapsets.cxx')
| -rw-r--r-- | tapsets.cxx | 462 |
1 files changed, 460 insertions, 2 deletions
diff --git a/tapsets.cxx b/tapsets.cxx index 06c0742c..5c7d46c1 100644 --- a/tapsets.cxx +++ b/tapsets.cxx @@ -2619,7 +2619,38 @@ struct uprobe_derived_probe: public derived_probe void join_group (systemtap_session& s); }; +struct kprobe_derived_probe: public derived_probe +{ + kprobe_derived_probe (probe *base, + probe_point *location, + const string& name, + int64_t stmt_addr, + bool has_return, + bool has_statement + ); + string symbol_name; + Dwarf_Addr addr; + bool has_return; + bool has_statement; + bool has_maxactive; + long maxactive_val; + bool access_var; + void printsig (std::ostream &o) const; + void join_group (systemtap_session& s); +}; + +struct kprobe_derived_probe_group: public derived_probe_group +{ +private: + multimap<string,kprobe_derived_probe*> probes_by_module; + typedef multimap<string,kprobe_derived_probe*>::iterator p_b_m_iterator; +public: + void enroll (kprobe_derived_probe* probe); + void emit_module_decls (systemtap_session& s); + void emit_module_init (systemtap_session& s); + void emit_module_exit (systemtap_session& s); +}; struct dwarf_derived_probe_group: public derived_probe_group { @@ -4449,7 +4480,6 @@ struct dwarf_var_expanding_visitor: public var_expanding_visitor }; - unsigned var_expanding_visitor::tick = 0; void @@ -5544,6 +5574,23 @@ dwarf_derived_probe_group::enroll (dwarf_derived_probe* p) // sequentially. } +/* +void +dwarf_derived_probe_group::enroll (kprobe_derived_probe* p) +{ + dwarf_derived_probe *dw_probe = new dwarf_derived_probe (p->symbol_name, + "",0, + p->module_name, + p->section_name, + 0,0, + p->q,NULL); + probes_by_module.insert (make_pair (p->module, p)); + + // XXX: probes put at the same address should all share a + // single kprobe/kretprobe, and have their handlers executed + // sequentially. +} +*/ void dwarf_derived_probe_group::emit_module_decls (systemtap_session& s) @@ -5626,6 +5673,7 @@ dwarf_derived_probe_group::emit_module_decls (systemtap_session& s) CALCIT(module); CALCIT(section); CALCIT(pp); +#undef CALCIT s.op->newline() << "const unsigned long address;"; s.op->newline() << "void (* const ph) (struct context*);"; @@ -6395,7 +6443,6 @@ emit_vma_callback_probe_decl (systemtap_session& s, s.op->line() << " },"; } - // ------------------------------------------------------------------------ // task_finder derived 'probes': These don't really exist. The whole // purpose of the task_finder_derived_probe_group is to make sure that @@ -8028,8 +8075,402 @@ uprobe_derived_probe_group::emit_module_exit (systemtap_session& s) s.op->newline() << "mutex_destroy (& stap_uprobes_lock);"; } +// ------------------------------------------------------------------------ +// Kprobe derived probes +// ------------------------------------------------------------------------ + +static string TOK_KPROBE("kprobe"); + +kprobe_derived_probe::kprobe_derived_probe (probe *base, + probe_point *location, + const string& name, + int64_t stmt_addr, + bool if_return, + bool if_statement +): + derived_probe (base, location), + symbol_name (name), addr (stmt_addr), + has_return (if_return), has_statement (if_statement) +{ + this->tok = base->tok; + this->access_var = false; + +#ifndef USHRT_MAX +#define USHRT_MAX 32767 +#endif + + // Expansion of $target variables in the probe body produces an error during translate phase + vector<probe_point::component*> comps; + + if (has_return) + comps.push_back (new probe_point::component(TOK_RETURN)); + this->sole_location()->components = comps; +} +void kprobe_derived_probe::printsig (ostream& o) const +{ + sole_location()->print (o); + o << " /* " << " name = " << symbol_name << "*/"; + printsig_nested (o); +} + +void kprobe_derived_probe::join_group (systemtap_session& s) +{ + + if (! s.kprobe_derived_probes) + s.kprobe_derived_probes = new kprobe_derived_probe_group (); + s.kprobe_derived_probes->enroll (this); + +} + +void kprobe_derived_probe_group::enroll (kprobe_derived_probe* p) +{ + probes_by_module.insert (make_pair (p->symbol_name, p)); + // probes of same symbol should share single kprobe/kretprobe +} + +void +kprobe_derived_probe_group::emit_module_decls (systemtap_session& s) +{ + if (probes_by_module.empty()) return; + + s.op->newline() << "/* ---- kprobe-based probes ---- */"; + + // Warn of misconfigured kernels + s.op->newline() << "#if ! defined(CONFIG_KPROBES)"; + s.op->newline() << "#error \"Need CONFIG_KPROBES!\""; + s.op->newline() << "#endif"; + s.op->newline(); + + // Forward declare the master entry functions + s.op->newline() << "static int enter_kprobe_probe (struct kprobe *inst,"; + s.op->line() << " struct pt_regs *regs);"; + s.op->newline() << "static int enter_kretprobe_probe (struct kretprobe_instance *inst,"; + s.op->line() << " struct pt_regs *regs);"; + + // Emit an array of kprobe/kretprobe pointers + s.op->newline() << "#if defined(STAPCONF_UNREGISTER_KPROBES)"; + s.op->newline() << "static void * stap_unreg_kprobes[" << probes_by_module.size() << "];"; + s.op->newline() << "#endif"; + + // Emit the actual probe list. + + s.op->newline() << "static struct stap_dwarfless_kprobe {"; + s.op->newline(1) << "union { struct kprobe kp; struct kretprobe krp; } u;"; + s.op->newline() << "#ifdef __ia64__"; + s.op->newline() << "struct kprobe dummy;"; + s.op->newline() << "#endif"; + s.op->newline(-1) << "} stap_dwarfless_kprobes[" << probes_by_module.size() << "];"; + // NB: bss! + + s.op->newline() << "static struct stap_dwarfless_probe {"; + s.op->newline(1) << "const unsigned return_p:1;"; + s.op->newline() << "const unsigned maxactive_p:1;"; + s.op->newline() << "const unsigned statement_p:1;"; + s.op->newline() << "unsigned registered_p:1;"; + s.op->newline() << "const unsigned short maxactive_val;"; + + // Function Names are mostly small and uniform enough to justify putting + // char[MAX]'s into the array instead of relocated char*'s. + + size_t pp_name_max = 0, symbol_string_name_max = 0; + size_t pp_name_tot = 0, symbol_string_name_tot = 0; + for (p_b_m_iterator it = probes_by_module.begin(); it != probes_by_module.end(); it++) + { + kprobe_derived_probe* p = it->second; +#define DOIT(var,expr) do { \ + size_t var##_size = (expr) + 1; \ + var##_max = max (var##_max, var##_size); \ + var##_tot += var##_size; } while (0) + DOIT(pp_name, lex_cast_qstring(*p->sole_location()).size()); + DOIT(symbol_string_name, p->symbol_name.size()); +#undef DOIT + } + +#define CALCIT(var) \ + s.op->newline() << "const char " << #var << "[" << var##_name_max << "] ;"; + + CALCIT(pp); + CALCIT(symbol_string); +#undef CALCIT + + s.op->newline() << "const unsigned long address;"; + s.op->newline() << "void (* const ph) (struct context*);"; + s.op->newline(-1) << "} stap_dwarfless_probes[] = {"; + s.op->indent(1); + + for (p_b_m_iterator it = probes_by_module.begin(); it != probes_by_module.end(); it++) + { + kprobe_derived_probe* p = it->second; + s.op->newline() << "{"; + if (p->has_return) + s.op->line() << " .return_p=1,"; + + if (p->has_maxactive) + { + s.op->line() << " .maxactive_p=1,"; + assert (p->maxactive_val >= 0 && p->maxactive_val <= USHRT_MAX); + s.op->line() << " .maxactive_val=" << p->maxactive_val << ","; + } + if (p->has_statement) + { + s.op->line() << " .statement_p=1,"; + s.op->line() << " .address=(unsigned long)0x" << hex << p->addr << dec << "ULL,"; + s.op->line() << " .symbol_string=\"" << "\","; + } + else + { + s.op->line() << " .address=(unsigned long)0x" << hex << 0 << dec << "ULL,"; + s.op->line() << " .symbol_string=\"" << p->symbol_name << "\","; + } + + s.op->line() << " .pp=" << lex_cast_qstring (*p->sole_location()) << ","; + s.op->line() << " .ph=&" << p->name; + s.op->line() << " },"; + } + + s.op->newline(-1) << "};"; + + // Emit the kprobes callback function + s.op->newline(); + s.op->newline() << "static int enter_kprobe_probe (struct kprobe *inst,"; + s.op->line() << " struct pt_regs *regs) {"; + // NB: as of PR5673, the kprobe|kretprobe union struct is in BSS + s.op->newline(1) << "int kprobe_idx = ((uintptr_t)inst-(uintptr_t)stap_dwarfless_kprobes)/sizeof(struct stap_dwarfless_kprobe);"; + // Check that the index is plausible + s.op->newline() << "struct stap_dwarfless_probe *sdp = &stap_dwarfless_probes["; + s.op->line() << "((kprobe_idx >= 0 && kprobe_idx < " << probes_by_module.size() << ")?"; + s.op->line() << "kprobe_idx:0)"; // NB: at least we avoid memory corruption + // XXX: it would be nice to give a more verbose error though; BUG_ON later? + s.op->line() << "];"; + common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", "sdp->pp"); + s.op->newline() << "c->regs = regs;"; + s.op->newline() << "(*sdp->ph) (c);"; + common_probe_entryfn_epilogue (s.op); + s.op->newline() << "return 0;"; + s.op->newline(-1) << "}"; + + // Same for kretprobes + s.op->newline(); + s.op->newline() << "static int enter_kretprobe_probe (struct kretprobe_instance *inst,"; + s.op->line() << " struct pt_regs *regs) {"; + s.op->newline(1) << "struct kretprobe *krp = inst->rp;"; + + // NB: as of PR5673, the kprobe|kretprobe union struct is in BSS + s.op->newline() << "int kprobe_idx = ((uintptr_t)krp-(uintptr_t)stap_dwarfless_kprobes)/sizeof(struct stap_dwarfless_kprobe);"; + // Check that the index is plausible + s.op->newline() << "struct stap_dwarfless_probe *sdp = &stap_dwarfless_probes["; + s.op->line() << "((kprobe_idx >= 0 && kprobe_idx < " << probes_by_module.size() << ")?"; + s.op->line() << "kprobe_idx:0)"; // NB: at least we avoid memory corruption + // XXX: it would be nice to give a more verbose error though; BUG_ON later? + s.op->line() << "];"; + + common_probe_entryfn_prologue (s.op, "STAP_SESSION_RUNNING", "sdp->pp"); + s.op->newline() << "c->regs = regs;"; + s.op->newline() << "c->pi = inst;"; // for assisting runtime's backtrace logic + s.op->newline() << "(*sdp->ph) (c);"; + common_probe_entryfn_epilogue (s.op); + s.op->newline() << "return 0;"; + s.op->newline(-1) << "}"; +} + + +void +kprobe_derived_probe_group::emit_module_init (systemtap_session& s) +{ +#define CHECK_STMT(var) \ + s.op->newline() << "if (sdp->statement_p) {"; \ + s.op->newline() << var << ".symbol_name = NULL;"; \ + s.op->newline() << "} else {"; \ + s.op->newline() << var << ".symbol_name = sdp->symbol_string;"; \ + s.op->newline() << "}"; + + s.op->newline() << "for (i=0; i<" << probes_by_module.size() << "; i++) {"; + s.op->newline() << "struct stap_dwarfless_probe *sdp = & stap_dwarfless_probes[i];"; + s.op->newline() << "struct stap_dwarfless_kprobe *kp = & stap_dwarfless_kprobes[i];"; + s.op->newline() << "unsigned long relocated_addr = sdp->address;"; + s.op->newline() << "probe_point = sdp->pp;"; // for error messages + s.op->newline() << "if (sdp->return_p) {"; + s.op->newline(1) << "kp->u.krp.kp.addr = (void *) relocated_addr;"; + CHECK_STMT("kp->u.krp.kp"); + s.op->newline() << "if (sdp->maxactive_p) {"; + s.op->newline(1) << "kp->u.krp.maxactive = sdp->maxactive_val;"; + s.op->newline(-1) << "} else {"; + s.op->newline(1) << "kp->u.krp.maxactive = max(10, 4*NR_CPUS);"; + s.op->newline(-1) << "}"; + s.op->newline() << "kp->u.krp.handler = &enter_kretprobe_probe;"; + // to ensure safeness of bspcache, always use aggr_kprobe on ia64 + s.op->newline() << "#ifdef __ia64__"; + s.op->newline() << "kp->dummy.pre_handler = NULL;"; + s.op->newline() << "kp->dummy.addr = kp->u.krp.kp.addr;"; + CHECK_STMT("kp->dummy"); + s.op->newline() << "rc = register_kprobe (& kp->dummy);"; + s.op->newline() << "if (rc == 0) {"; + s.op->newline(1) << "rc = register_kretprobe (& kp->u.krp);"; + s.op->newline() << "if (rc != 0)"; + s.op->newline(1) << "unregister_kprobe (& kp->dummy);"; + s.op->newline(-2) << "}"; + s.op->newline() << "#else"; + s.op->newline() << "rc = register_kretprobe (& kp->u.krp);"; + s.op->newline() << "#endif"; + s.op->newline(-1) << "} else {"; + // to ensure safeness of bspcache, always use aggr_kprobe on ia64 + s.op->newline(1) << "kp->u.kp.addr = (void *) relocated_addr;"; + CHECK_STMT("kp->u.kp"); + s.op->newline(1) << "kp->u.kp.pre_handler = &enter_kprobe_probe;"; + s.op->newline() << "#ifdef __ia64__"; + s.op->newline() << "kp->dummy.addr = kp->u.kp.addr;"; + s.op->newline() << "kp->dummy.pre_handler = NULL;"; + CHECK_STMT("kp->dummy"); + s.op->newline() << "rc = register_kprobe (& kp->dummy);"; + s.op->newline() << "if (rc == 0) {"; + s.op->newline(1) << "rc = register_kprobe (& kp->u.kp);"; + s.op->newline() << "if (rc != 0)"; + s.op->newline(1) << "unregister_kprobe (& kp->dummy);"; + s.op->newline(-2) << "}"; + s.op->newline() << "#else"; + s.op->newline() << "rc = register_kprobe (& kp->u.kp);"; + s.op->newline() << "#endif"; + s.op->newline(-1) << "}"; + s.op->newline() << "if (rc) {"; // PR6749: tolerate a failed register_*probe. + s.op->newline(1) << "sdp->registered_p = 0;"; + s.op->newline() << "if (rc == -EINVAL)"; + s.op->newline() << "{"; + s.op->newline() << " _stp_error (\"Error registering kprobe,possibly an incorrect name %s OR addr = %p, rc = %d \", sdp->symbol_string, sdp->address, rc);"; + s.op->newline() << " atomic_set (&session_state, STAP_SESSION_ERROR);"; + s.op->newline() << " goto out;"; + s.op->newline() << "}"; + s.op->newline() << "else"; + s.op->newline() << "_stp_warn (\"probe %s for %s registration error (rc %d)\", probe_point, sdp->pp, rc);"; + s.op->newline() << "rc = 0;"; // continue with other probes + // XXX: shall we increment numskipped? + s.op->newline(-1) << "}"; + + s.op->newline() << "else sdp->registered_p = 1;"; + s.op->newline(-1) << "}"; // for loop +#undef CHECK_STMT +} + +void +kprobe_derived_probe_group::emit_module_exit (systemtap_session& s) +{ + //Unregister kprobes by batch interfaces. + s.op->newline() << "#if defined(STAPCONF_UNREGISTER_KPROBES)"; + s.op->newline() << "j = 0;"; + s.op->newline() << "for (i=0; i<" << probes_by_module.size() << "; i++) {"; + s.op->newline(1) << "struct stap_dwarfless_probe *sdp = & stap_dwarfless_probes[i];"; + s.op->newline() << "struct stap_dwarfless_kprobe *kp = & stap_dwarfless_kprobes[i];"; + s.op->newline() << "if (! sdp->registered_p) continue;"; + s.op->newline() << "if (!sdp->return_p)"; + s.op->newline(1) << "stap_unreg_kprobes[j++] = &kp->u.kp;"; + s.op->newline(-2) << "}"; + s.op->newline() << "unregister_kprobes((struct kprobe **)stap_unreg_kprobes, j);"; + s.op->newline() << "j = 0;"; + s.op->newline() << "for (i=0; i<" << probes_by_module.size() << "; i++) {"; + s.op->newline(1) << "struct stap_dwarfless_probe *sdp = & stap_dwarfless_probes[i];"; + s.op->newline() << "struct stap_dwarfless_kprobe *kp = & stap_dwarfless_kprobes[i];"; + s.op->newline() << "if (! sdp->registered_p) continue;"; + s.op->newline() << "if (sdp->return_p)"; + s.op->newline(1) << "stap_unreg_kprobes[j++] = &kp->u.krp;"; + s.op->newline(-2) << "}"; + s.op->newline() << "unregister_kretprobes((struct kretprobe **)stap_unreg_kprobes, j);"; + s.op->newline() << "#ifdef __ia64__"; + s.op->newline() << "j = 0;"; + s.op->newline() << "for (i=0; i<" << probes_by_module.size() << "; i++) {"; + s.op->newline(1) << "struct stap_dwarfless_probe *sdp = & stap_dwarfless_probes[i];"; + s.op->newline() << "struct stap_dwarfless_kprobe *kp = & stap_dwarfless_kprobes[i];"; + s.op->newline() << "if (! sdp->registered_p) continue;"; + s.op->newline() << "stap_unreg_kprobes[j++] = &kp->dummy;"; + s.op->newline(-1) << "}"; + s.op->newline() << "unregister_kprobes((struct kprobe **)stap_unreg_kprobes, j);"; + s.op->newline() << "#endif"; + s.op->newline() << "#endif"; + + s.op->newline() << "for (i=0; i<" << probes_by_module.size() << "; i++) {"; + s.op->newline(1) << "struct stap_dwarfless_probe *sdp = & stap_dwarfless_probes[i];"; + s.op->newline() << "struct stap_dwarfless_kprobe *kp = & stap_dwarfless_kprobes[i];"; + s.op->newline() << "if (! sdp->registered_p) continue;"; + s.op->newline() << "if (sdp->return_p) {"; + s.op->newline() << "#if !defined(STAPCONF_UNREGISTER_KPROBES)"; + s.op->newline(1) << "unregister_kretprobe (&kp->u.krp);"; + s.op->newline() << "#endif"; + s.op->newline() << "atomic_add (kp->u.krp.nmissed, & skipped_count);"; + s.op->newline() << "#ifdef STP_TIMING"; + s.op->newline() << "if (kp->u.krp.nmissed)"; + s.op->newline(1) << "_stp_warn (\"Skipped due to missed kretprobe/1 on '%s': %d\\n\", sdp->pp, kp->u.krp.nmissed);"; + s.op->newline(-1) << "#endif"; + s.op->newline() << "atomic_add (kp->u.krp.kp.nmissed, & skipped_count);"; + s.op->newline() << "#ifdef STP_TIMING"; + s.op->newline() << "if (kp->u.krp.kp.nmissed)"; + s.op->newline(1) << "_stp_warn (\"Skipped due to missed kretprobe/2 on '%s': %d\\n\", sdp->pp, kp->u.krp.kp.nmissed);"; + s.op->newline(-1) << "#endif"; + s.op->newline(-1) << "} else {"; + s.op->newline() << "#if !defined(STAPCONF_UNREGISTER_KPROBES)"; + s.op->newline(1) << "unregister_kprobe (&kp->u.kp);"; + s.op->newline() << "#endif"; + s.op->newline() << "atomic_add (kp->u.kp.nmissed, & skipped_count);"; + s.op->newline() << "#ifdef STP_TIMING"; + s.op->newline() << "if (kp->u.kp.nmissed)"; + s.op->newline(1) << "_stp_warn (\"Skipped due to missed kprobe on '%s': %d\\n\", sdp->pp, kp->u.kp.nmissed);"; + s.op->newline(-1) << "#endif"; + s.op->newline(-1) << "}"; + s.op->newline() << "#if !defined(STAPCONF_UNREGISTER_KPROBES) && defined(__ia64__)"; + s.op->newline() << "unregister_kprobe (&kp->dummy);"; + s.op->newline() << "#endif"; + s.op->newline() << "sdp->registered_p = 0;"; + s.op->newline(-1) << "}"; +} + +struct kprobe_builder: public derived_probe_builder +{ + kprobe_builder() {} + virtual void build(systemtap_session & sess, + probe * base, + probe_point * location, + literal_map_t const & parameters, + vector<derived_probe *> & finished_results); +}; + + +void +kprobe_builder::build(systemtap_session & sess, + probe * base, + probe_point * location, + literal_map_t const & parameters, + vector<derived_probe *> & finished_results) +{ + string function_string_val, module_string_val; + int64_t statement_num_val = 0; + bool has_function_str, has_module_str, has_statement_num, has_absolute, has_return; + + has_function_str = this->get_param(parameters, TOK_FUNCTION, function_string_val); + has_module_str = this->get_param(parameters, TOK_MODULE, module_string_val); + has_return = this->has_null_param (parameters, TOK_RETURN); + has_statement_num = this->get_param(parameters, TOK_STATEMENT, statement_num_val); + has_absolute = this->has_null_param (parameters, TOK_ABSOLUTE); + + if ( has_function_str ) + { + if ( has_module_str ) + function_string_val = module_string_val + ":" + function_string_val; + finished_results.push_back ( new kprobe_derived_probe ( base, + location, function_string_val, + 0, has_return, + has_statement_num) ); + } + else + { + // assert guru mode for absolute probes + if ( has_statement_num && has_absolute && !base->privileged ) + throw semantic_error ("absolute statement probe in unprivileged script", base->tok); + + finished_results.push_back(new kprobe_derived_probe ( base, + location,"", + statement_num_val, has_return, + has_statement_num)); + } +} // ------------------------------------------------------------------------ // timer derived probes // ------------------------------------------------------------------------ @@ -11053,6 +11494,10 @@ perfmon_derived_probe_group::emit_module_init (translator_output* o) } #endif +// ------------------------------------------------------------------------ +// kprobes-based probes,which postpone symbol resolution until runtime. +// ------------------------------------------------------------------------ + // ------------------------------------------------------------------------ // Standard tapset registry. @@ -11151,6 +11596,18 @@ register_standard_tapsets(systemtap_session & s) s.pattern_root->bind(TOK_PROCFS)->bind(TOK_WRITE)->bind(new procfs_builder()); s.pattern_root->bind_str(TOK_PROCFS)->bind(TOK_WRITE) ->bind(new procfs_builder()); + + // Kprobe based probe + s.pattern_root->bind(TOK_KPROBE)->bind_str(TOK_FUNCTION) + ->bind(new kprobe_builder()); + s.pattern_root->bind(TOK_KPROBE)->bind_str(TOK_MODULE) + ->bind_str(TOK_FUNCTION)->bind(new kprobe_builder()); + s.pattern_root->bind(TOK_KPROBE)->bind_str(TOK_FUNCTION)->bind(TOK_RETURN) + ->bind(new kprobe_builder()); + s.pattern_root->bind(TOK_KPROBE)->bind_str(TOK_MODULE) + ->bind_str(TOK_FUNCTION)->bind(TOK_RETURN)->bind(new kprobe_builder()); + s.pattern_root->bind(TOK_KPROBE)->bind_num(TOK_STATEMENT) + ->bind(TOK_ABSOLUTE)->bind(new kprobe_builder()); } @@ -11173,6 +11630,7 @@ all_session_groups(systemtap_session& s) DOONE(profile); DOONE(mark); DOONE(tracepoint); + DOONE(kprobe); DOONE(hrtimer); DOONE(perfmon); DOONE(procfs); |