// tapset for HW performance monitoring
// Copyright (C) 2005-2019 Red Hat Inc.
// Copyright (C) 2005-2007 Intel Corporation.
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.

#include "session.h"
#include "tapsets.h"
#include "task_finder.h"
#include "translate.h"
#include "util.h"

#include <string>

extern "C" {
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
}

using namespace std;
using namespace __gnu_cxx;


static const string TOK_PERF("perf");
static const string TOK_TYPE("type");
static const string TOK_CONFIG("config");
static const string TOK_SAMPLE("sample");
static const string TOK_HZ("hz");
static const string TOK_PROCESS("process");
static const string TOK_COUNTER("counter");


// ------------------------------------------------------------------------
// perf event derived probes
// ------------------------------------------------------------------------
// This is a new interface to the perfmon hw.
//

struct perf_derived_probe: public derived_probe
{
  int64_t event_type;
  int64_t event_config;
  int64_t interval;
  bool has_process;
  bool has_counter;
  bool has_freq;
  string process_name;
  string counter;
  perf_derived_probe (probe* p, probe_point* l, int64_t type, int64_t config,
		      int64_t i, bool pp, bool cp, bool freq, string pn, string cv);
  virtual void join_group (systemtap_session& s);
};


struct perf_derived_probe_group: public generic_dpg<perf_derived_probe>
{
  friend bool sort_for_bpf(systemtap_session& s
			   ,perf_derived_probe_group *pg,
                           sort_for_bpf_probe_arg_vector &v);

  void emit_module_decls (systemtap_session& s);
  void emit_module_init (systemtap_session& s);
  void emit_module_exit (systemtap_session& s);
};


perf_derived_probe::perf_derived_probe (probe* p, probe_point* l,
                                        int64_t type,
                                        int64_t config,
                                        int64_t i,
					bool process_p,
					bool counter_p,
					bool freq,
					string process_n,
					string counter):
  
  derived_probe (p, l, true /* .components soon rewritten */),
  event_type (type), event_config (config), interval (i),
  has_process (process_p), has_counter (counter_p), has_freq(freq),
  process_name (process_n), counter (counter)
{
  vector<probe_point::component*>& comps = this->sole_location()->components;
  comps.clear();
  comps.push_back (new probe_point::component (TOK_PERF));
  comps.push_back (new probe_point::component (TOK_TYPE, new literal_number(type)));
  comps.push_back (new probe_point::component (TOK_CONFIG, new literal_number (config)));
  comps.push_back (new probe_point::component (TOK_SAMPLE, new literal_number (interval)));
  if (has_process)
    comps.push_back (new probe_point::component (TOK_PROCESS, new literal_string (process_name)));
  if (has_counter)
    comps.push_back (new probe_point::component (TOK_COUNTER, new literal_string (counter)));
}


void
perf_derived_probe::join_group (systemtap_session& s)
{
  if (! s.perf_derived_probes)
    s.perf_derived_probes = new perf_derived_probe_group ();
  s.perf_derived_probes->enroll (this);
  this->group = s.perf_derived_probes;

  if (has_process && !has_counter)
    enable_task_finder(s);
}


void
perf_derived_probe_group::emit_module_decls (systemtap_session& s)
{
  bool have_a_process_tag = false;

  for (unsigned i=0; i < probes.size(); i++)
    if (probes[i]->has_process && !probes[i]->has_counter)
      {
	have_a_process_tag = true;
	break;
      }

  if (probes.empty()) return;

  s.op->newline() << "/* ---- perf probes ---- */";
  s.op->newline() << "#include <linux/perf_event.h>";
  s.op->newline() << "#include \"linux/perf.h\"";
  s.op->newline();

  /* declarations */
  s.op->newline() << "static void handle_perf_probe (unsigned i, struct pt_regs *regs);";
  for (unsigned i=0; i < probes.size(); i++)
    {
      s.op->newline() << "#ifdef STAPCONF_PERF_HANDLER_NMI";
      s.op->newline() << "static void enter_perf_probe_" << i
                      << " (struct perf_event *e, int nmi, "
                      << "struct perf_sample_data *data, "
                      << "struct pt_regs *regs);";
      s.op->newline() << "#else";
      s.op->newline() << "static void enter_perf_probe_" << i
                      << " (struct perf_event *e, "
                      << "struct perf_sample_data *data, "
                      << "struct pt_regs *regs);";
      s.op->newline() << "#endif";
    }
  s.op->newline();

  // Output task finder callback routine
  if (have_a_process_tag)
    {
      s.op->newline() << "static int _stp_perf_probe_cb(struct stap_task_finder_target *tgt, struct task_struct *tsk, int register_p, int process_p) {";
      s.op->indent(1);
      s.op->newline() << "int rc = 0;";
      s.op->newline() << "struct stap_perf_probe *p = container_of(tgt, struct stap_perf_probe, e.t.tgt);";
      
      s.op->newline() << "mutex_lock(&p->cb_lock);";
      s.op->newline() << "if (register_p) ";
      s.op->indent(1);
      
      s.op->newline() << "rc = _stp_perf_init(p, tsk);";
      s.op->newline(-1) << "else";
      s.op->newline(1) << "_stp_perf_del(p);";
      s.op->newline(-1) << "mutex_unlock(&p->cb_lock);";
      s.op->newline() << "return rc;";
      s.op->newline(-1) << "}";
    }

  /* data structures */
  s.op->newline() << "static struct stap_perf_probe stap_perf_probes ["
                  << probes.size() << "] = {";
  s.op->indent(1);
  for (unsigned i=0; i < probes.size(); i++)
    {
      s.op->newline() << "{";
      s.op->newline(1) << ".attr={ "
                       << ".type=" << probes[i]->event_type << "ULL, "
                       << ".config=" << probes[i]->event_config << "ULL, ";
      if (probes[i]->has_freq)
        {
          s.op->line() << "{ .sample_freq=" << probes[i]->interval << "ULL }, ";
          s.op->line() << ".freq=1, ";
        }
      else
        {
          s.op->line() << "{ .sample_period=" << probes[i]->interval << "ULL }, ";
        }
      s.op->line() << "},";
      s.op->newline() << ".callback=enter_perf_probe_" << i << ", ";
      s.op->newline() << ".probe=" << common_probe_init (probes[i]) << ", ";

      if (probes[i]->has_process && !probes[i]->has_counter)
	{
	  s.op->line() << " .e={";
	  s.op->line() << " .t={";
	  s.op->line() << " .tgt={";
	  s.op->line() << " .purpose=\"perfctr\",";
	  s.op->line() << " .procname=\"" << probes[i]->process_name << "\",";
	  s.op->line() << " .pid=0,";
	  s.op->line() << " .callback=&_stp_perf_probe_cb,";
	  s.op->line() << " },";
	  s.op->line() << " },";
	  s.op->line() << " },";
	  s.op->newline() << ".task_finder=" << "1, ";
	}
      else if (probes[i]->has_counter)
	{
	  // process counters are currently task-found by uprobes
	  // set neither .system_wide nor .task_finder
	}
      else
	s.op->newline() << ".system_wide=" << "1, ";
      s.op->newline() << ".cb_lock = __MUTEX_INITIALIZER(stap_perf_probes[" << i << "].cb_lock),";
      s.op->newline(-1) << "},";
    }
  s.op->newline(-1) << "};";
  s.op->newline();

  /* wrapper functions */
  for (unsigned i=0; i < probes.size(); i++)
    {
      s.op->newline() << "#ifdef STAPCONF_PERF_HANDLER_NMI";
      s.op->newline() << "static void enter_perf_probe_" << i
                      << " (struct perf_event *e, int nmi, "
                      << "struct perf_sample_data *data, "
                      << "struct pt_regs *regs)";
      s.op->newline() << "#else";
      s.op->newline() << "static void enter_perf_probe_" << i
                      << " (struct perf_event *e, "
                      << "struct perf_sample_data *data, "
                      << "struct pt_regs *regs)";
      s.op->newline() << "#endif";
      s.op->newline() << "{";
      s.op->newline(1) << "handle_perf_probe(" << i << ", regs);";
      s.op->newline(-1) << "}";
    }
  s.op->newline();

  s.op->newline() << "static void handle_perf_probe (unsigned i, struct pt_regs *regs)";
  s.op->newline() << "{";
  s.op->newline(1) << "struct stap_perf_probe* stp = & stap_perf_probes [i];";
  common_probe_entryfn_prologue (s, "STAP_SESSION_RUNNING", "", "stp->probe",
				 "stp_probe_type_perf");
  s.op->newline() << "if (user_mode(regs)) {";
  s.op->newline(1)<< "c->user_mode_p = 1;";
  s.op->newline() << "c->uregs = regs;";
  s.op->newline(-1) << "} else {";
  s.op->newline(1) << "c->kregs = regs;";
  s.op->newline(-1) << "}";

  s.op->newline() << "(*stp->probe->ph) (c);";
  common_probe_entryfn_epilogue (s, true, otf_safe_context(s));
  s.op->newline(-1) << "}";
  s.op->newline();
  if (have_a_process_tag)
    s.op->newline() << "#define STP_PERF_USE_TASK_FINDER 1";
  s.op->newline() << "#include \"linux/perf.c\"";
  s.op->newline();
}


void
perf_derived_probe_group::emit_module_init (systemtap_session& s)
{
  if (probes.empty()) return;

  s.op->newline() << "rc = _stp_perf_init_n (stap_perf_probes, "
		  << probes.size() << ", &probe_point);";
}


void
perf_derived_probe_group::emit_module_exit (systemtap_session& s)
{
  if (probes.empty()) return;

  s.op->newline() << "_stp_perf_del_n (stap_perf_probes, "
		  << probes.size() << ");";
}


struct perf_builder: public derived_probe_builder
{
    virtual void build(systemtap_session & sess,
                       probe * base, probe_point * location,
                       literal_map_t const & parameters,
                       vector<derived_probe *> & finished_results);

    static void register_patterns(systemtap_session& s);

    virtual string name() { return "perf builder"; }
};


void
perf_builder::build(systemtap_session & sess,
		    probe * base,
		    probe_point * location,
		    literal_map_t const & parameters,
		    vector<derived_probe *> & finished_results)
{
  // XXX need additional version checks too?
  // --- perhaps look for export of perf_event_create_kernel_counter
  if (sess.kernel_exports.find("perf_event_create_kernel_counter") == sess.kernel_exports.end())
    throw SEMANTIC_ERROR (_("perf probes not available without exported perf_event_create_kernel_counter"));
  if (sess.kernel_config["CONFIG_PERF_EVENTS"] != "y")
    throw SEMANTIC_ERROR (_("perf probes not available without CONFIG_PERF_EVENTS"));

  int64_t type;
  bool has_type = get_param(parameters, TOK_TYPE, type);
  assert(has_type);

  int64_t config;
  bool has_config = get_param(parameters, TOK_CONFIG, config);
  assert(has_config);

  int64_t period;
  bool has_period = get_param(parameters, TOK_SAMPLE, period);
  if (!has_period)
    period = 1000000; // XXX: better parametrize this default
  else if (period < 1)
    throw SEMANTIC_ERROR(_("invalid perf sample period ") + lex_cast(period),
                         parameters.find(TOK_SAMPLE)->second->tok);

  int64_t freq;
  bool has_freq = get_param(parameters, TOK_HZ, freq);

  interned_string var;
  bool has_counter = get_param(parameters, TOK_COUNTER, var);
  if (var.find_first_of("*?[") != string::npos)
    throw SEMANTIC_ERROR(_("wildcard not allowed with perf probe counter component"));
  if (has_counter)
    {
      if (var.empty())
	throw SEMANTIC_ERROR(_("missing perf probe counter component name"));

      period = 0;		// perf_event_attr.sample_freq should be 0
      vector<std::pair<string,string> >:: iterator it;
      for (it=sess.perf_counters.begin() ;
	   it != sess.perf_counters.end(); it++)
	if ((*it).first == var)
	  break;
      if (it != sess.perf_counters.end())
	throw SEMANTIC_ERROR(_("duplicate counter name"));

      // Splice a 'next' into the probe body, and then elaborate.cxx's
      // dead_stmtexpr_remover() will warn if anything of substance follows.
      statement* n = new next_statement ();
      n->tok = base->tok;
      base->body = new block (n, base->body);
    }

  bool proc_p;
  interned_string proc_n;
  if ((proc_p = has_null_param(parameters, TOK_PROCESS)))
    {
      try
        {
          proc_n = sess.cmd_file();
        }
      catch (semantic_error& e)
        {
          throw SEMANTIC_ERROR(_("invalid -c command for unspecified process"
                                 " probe [man stapprobes]"), NULL, NULL, &e);
        }
      if (proc_n.empty())
	throw SEMANTIC_ERROR(_("unspecified process probe is invalid without a "
                               "-c COMMAND [man stapprobes]"));
    }
  else
    proc_p = get_param(parameters, TOK_PROCESS, proc_n);
  if (proc_p && !proc_n.empty())
    proc_n = find_executable (proc_n, sess.sysroot, sess.sysenv);

  if (sess.verbose > 1)
    clog << _F("perf probe type=%" PRId64 " config=%" PRId64 " %s=%" PRId64 " process=%s counter=%s",
	       type, config, has_freq ? "freq" : "period", has_freq ? freq : period,
               proc_n.to_string().c_str(), var.to_string().c_str()) << endl;

  // The user-provided pp is already well-formed. Let's add a copy on the chain
  // and set it as the new base
  probe_point *new_location = new probe_point(*location);
  new_location->well_formed = true;
  probe *new_base = new probe(base, new_location);

  finished_results.push_back
    (new perf_derived_probe(new_base, location, type, config,
                            has_freq ? freq : period, proc_p,
			    has_counter, has_freq, proc_n, var));
  if (!var.empty())
    sess.perf_counters.push_back(make_pair (var, proc_n));
}


void
register_tapset_perf(systemtap_session& s)
{
  // NB: at this point, the binding is *not* unprivileged.

  derived_probe_builder *builder = new perf_builder();
  match_node* perf = s.pattern_root->bind(TOK_PERF);

  match_node* event = perf->bind_num(TOK_TYPE)->bind_num(TOK_CONFIG);
  event->bind(builder);
  event->bind_num(TOK_SAMPLE)->bind(builder);
  event->bind_num(TOK_HZ)->bind(builder);
  event->bind_str(TOK_PROCESS)->bind(builder);
  event->bind(TOK_PROCESS)->bind(builder);
  event->bind_str(TOK_COUNTER)->bind(builder);
  event->bind_str(TOK_PROCESS)->bind_str(TOK_COUNTER)->bind(builder);
}

bool
sort_for_bpf(systemtap_session& s __attribute__ ((unused)),
	     perf_derived_probe_group *pg, sort_for_bpf_probe_arg_vector &v)
{
  if (!pg)
    return false;

  for (auto i = pg->probes.begin(); i != pg->probes.end(); ++i)
    {
      perf_derived_probe *p = *i;
      std::stringstream o;

      o << "perf/" << p->event_type << "/" << p->event_config << "/";
      if (p->has_freq)
        o << "f/" << p->interval;  // uses sample_freq (hz)
      else
        o << "p/" << p->interval;  // uses sample_period

      // XXX .process, .counter
      v.push_back(std::pair<derived_probe *, std::string>(p, o.str()));
    }

  return v.empty();
}

/* vim: set sw=2 ts=8 cino=>4,n-2,{2,^-2,t0,(0,u0,w1,M1 : */
