include/rv/ltl_monitor.h

/* 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 <rv/kunit.h>
#include <trace/events/task.h>
#include <trace/events/sched.h>

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

static struct rv_monitor rv_this;

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);

	tracepoint_synchronize_unregister();
	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_this, "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);
}

#if IS_ENABLED(CONFIG_RV_MONITORS_KUNIT_TEST)
#define RV_MON_OPS_INIT() {               \
	.rv_this = &rv_this,              \
	.is_per_task = true,              \
	.task_slot = &ltl_monitor_slot,   \
}
#endif /* CONFIG_RV_MONITORS_KUNIT_TEST */