/* SPDX-License-Identifier: GPL-2.0 */
/**
 * This file must be combined with the $(MODEL_NAME).h file generated by
 * tools/verification/rvgen.
 */

#include <linux/args.h>
#include <linux/rv.h>
#include <linux/stringify.h>
#include <linux/seq_buf.h>
#include <rv/instrumentation.h>
#include <trace/events/task.h>
#include <trace/events/sched.h>

#ifndef MONITOR_NAME
#error "Please include $(MODEL_NAME).h generated by rvgen"
#endif

#define RV_MONITOR_NAME CONCATENATE(rv_, MONITOR_NAME)
static struct rv_monitor RV_MONITOR_NAME;

static int ltl_monitor_slot = RV_PER_TASK_MONITOR_INIT;

static void ltl_atoms_fetch(struct task_struct *task, struct ltl_monitor *mon);
static void ltl_atoms_init(struct task_struct *task, struct ltl_monitor *mon, bool task_creation);

static struct ltl_monitor *ltl_get_monitor(struct task_struct *task)
{
        return &task->rv[ltl_monitor_slot].ltl_mon;
}

static void ltl_task_init(struct task_struct *task, bool task_creation)
{
        struct ltl_monitor *mon = ltl_get_monitor(task);

        memset(&mon->states, 0, sizeof(mon->states));

        for (int i = 0; i < LTL_NUM_ATOM; ++i)
                __set_bit(i, mon->unknown_atoms);

        ltl_atoms_init(task, mon, task_creation);
        ltl_atoms_fetch(task, mon);
}

static void handle_task_newtask(void *data, struct task_struct *task, u64 flags)
{
        ltl_task_init(task, true);
}

static int ltl_monitor_init(void)
{
        struct task_struct *g, *p;
        int ret, cpu;

        ret = rv_get_task_monitor_slot();
        if (ret < 0)
                return ret;

        ltl_monitor_slot = ret;

        rv_attach_trace_probe(name, task_newtask, handle_task_newtask);

        read_lock(&tasklist_lock);

        for_each_process_thread(g, p)
                ltl_task_init(p, false);

        for_each_present_cpu(cpu)
                ltl_task_init(idle_task(cpu), false);

        read_unlock(&tasklist_lock);

        return 0;
}

static void ltl_monitor_destroy(void)
{
        rv_detach_trace_probe(name, task_newtask, handle_task_newtask);

        rv_put_task_monitor_slot(ltl_monitor_slot);
        ltl_monitor_slot = RV_PER_TASK_MONITOR_INIT;
}

static void ltl_illegal_state(struct task_struct *task, struct ltl_monitor *mon)
{
        CONCATENATE(trace_error_, MONITOR_NAME)(task);
        rv_react(&RV_MONITOR_NAME, "rv: "__stringify(MONITOR_NAME)": %s[%d]: violation detected\n",
                 task->comm, task->pid);
}

static void ltl_attempt_start(struct task_struct *task, struct ltl_monitor *mon)
{
        if (rv_ltl_all_atoms_known(mon))
                ltl_start(task, mon);
}

static inline void ltl_atom_set(struct ltl_monitor *mon, enum ltl_atom atom, bool value)
{
        __clear_bit(atom, mon->unknown_atoms);
        if (value)
                __set_bit(atom, mon->atoms);
        else
                __clear_bit(atom, mon->atoms);
}

static void
ltl_trace_event(struct task_struct *task, struct ltl_monitor *mon, unsigned long *next_state)
{
        const char *format_str = "%s";
        DECLARE_SEQ_BUF(atoms, 64);
        char states[32], next[32];
        int i;

        if (!CONCATENATE(CONCATENATE(trace_event_, MONITOR_NAME), _enabled)())
                return;

        snprintf(states, sizeof(states), "%*pbl", RV_MAX_BA_STATES, mon->states);
        snprintf(next, sizeof(next), "%*pbl", RV_MAX_BA_STATES, next_state);

        for (i = 0; i < LTL_NUM_ATOM; ++i) {
                if (test_bit(i, mon->atoms)) {
                        seq_buf_printf(&atoms, format_str, ltl_atom_str(i));
                        format_str = ",%s";
                }
        }

        CONCATENATE(trace_event_, MONITOR_NAME)(task, states, atoms.buffer, next);
}

static void ltl_validate(struct task_struct *task, struct ltl_monitor *mon)
{
        DECLARE_BITMAP(next_states, RV_MAX_BA_STATES) = {0};

        if (!rv_ltl_valid_state(mon))
                return;

        for (unsigned int i = 0; i < RV_NUM_BA_STATES; ++i) {
                if (test_bit(i, mon->states))
                        ltl_possible_next_states(mon, i, next_states);
        }

        ltl_trace_event(task, mon, next_states);

        memcpy(mon->states, next_states, sizeof(next_states));

        if (!rv_ltl_valid_state(mon))
                ltl_illegal_state(task, mon);
}

static void ltl_atom_update(struct task_struct *task, enum ltl_atom atom, bool value)
{
        struct ltl_monitor *mon = ltl_get_monitor(task);

        ltl_atom_set(mon, atom, value);
        ltl_atoms_fetch(task, mon);

        if (!rv_ltl_valid_state(mon)) {
                ltl_attempt_start(task, mon);
                return;
        }

        ltl_validate(task, mon);
}

static void __maybe_unused ltl_atom_pulse(struct task_struct *task, enum ltl_atom atom, bool value)
{
        struct ltl_monitor *mon = ltl_get_monitor(task);

        ltl_atom_update(task, atom, value);

        ltl_atom_set(mon, atom, !value);
        ltl_validate(task, mon);
}