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// SPDX-License-Identifier: GPL-2.0
#include <linux/ftrace.h>
#include <linux/tracepoint.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rv.h>
#include <rv/instrumentation.h>
#define MODULE_NAME "wakeup"
#include <trace/events/syscalls.h>
#include <trace/events/sched.h>
#include <trace/events/lock.h>
#include <uapi/linux/futex.h>
#include <rv_trace.h>
#include <monitors/rtapp/rtapp.h>
#ifndef __NR_futex
#define __NR_futex (-__COUNTER__)
#endif
#ifndef __NR_futex_time64
#define __NR_futex_time64 (-__COUNTER__)
#endif
#include "wakeup.h"
#include <rv/ltl_monitor.h>
static void ltl_atoms_fetch(struct task_struct *task, struct ltl_monitor *mon)
{
/*
* This includes "actual" real-time tasks and also PI-boosted
* tasks. A task being PI-boosted means it is blocking an "actual"
* real-task, therefore it should also obey the monitor's rule,
* otherwise the "actual" real-task may be delayed.
*/
ltl_atom_set(mon, LTL_RT, rt_or_dl_task(task));
}
static void ltl_atoms_init(struct task_struct *task, struct ltl_monitor *mon, bool task_creation)
{
ltl_atom_set(mon, LTL_WOKEN_BY_LOWER_PRIO, false);
ltl_atom_set(mon, LTL_WOKEN_BY_SOFTIRQ, false);
if (task_creation) {
ltl_atom_set(mon, LTL_BLOCK_ON_RT_MUTEX, false);
ltl_atom_set(mon, LTL_FUTEX_LOCK_PI, false);
}
ltl_atom_set(mon, LTL_USER_THREAD, !(task->flags & PF_KTHREAD));
}
static void handle_sched_waking(void *data, struct task_struct *task)
{
if (in_task()) {
if (current->prio > task->prio)
ltl_atom_pulse(task, LTL_WOKEN_BY_LOWER_PRIO, true);
} else if (in_serving_softirq()) {
ltl_atom_pulse(task, LTL_WOKEN_BY_SOFTIRQ, true);
}
}
static void handle_contention_begin(void *data, void *lock, unsigned int flags)
{
if (flags & LCB_F_RT)
ltl_atom_update(current, LTL_BLOCK_ON_RT_MUTEX, true);
}
static void handle_contention_end(void *data, void *lock, int ret)
{
ltl_atom_update(current, LTL_BLOCK_ON_RT_MUTEX, false);
}
static void handle_sys_enter(void *data, struct pt_regs *regs, long id)
{
unsigned long args[6];
int op, cmd;
switch (id) {
case __NR_futex:
case __NR_futex_time64:
syscall_get_arguments(current, regs, args);
op = args[1];
cmd = op & FUTEX_CMD_MASK;
switch (cmd) {
case FUTEX_LOCK_PI:
case FUTEX_LOCK_PI2:
ltl_atom_update(current, LTL_FUTEX_LOCK_PI, true);
break;
}
break;
}
}
static void handle_sys_exit(void *data, struct pt_regs *regs, long ret)
{
ltl_atom_update(current, LTL_FUTEX_LOCK_PI, false);
}
static int enable_wakeup(void)
{
int retval;
retval = ltl_monitor_init();
if (retval)
return retval;
rv_attach_trace_probe("rtapp_wakeup", sched_waking, handle_sched_waking);
rv_attach_trace_probe("rtapp_wakeup", contention_begin, handle_contention_begin);
rv_attach_trace_probe("rtapp_wakeup", contention_end, handle_contention_end);
rv_attach_trace_probe("rtapp_wakeup", sys_enter, handle_sys_enter);
rv_attach_trace_probe("rtapp_wakeup", sys_exit, handle_sys_exit);
return 0;
}
static void disable_wakeup(void)
{
rv_detach_trace_probe("rtapp_wakeup", sched_waking, handle_sched_waking);
rv_detach_trace_probe("rtapp_wakeup", contention_begin, handle_contention_begin);
rv_detach_trace_probe("rtapp_wakeup", contention_end, handle_contention_end);
rv_detach_trace_probe("rtapp_wakeup", sys_enter, handle_sys_enter);
rv_detach_trace_probe("rtapp_wakeup", sys_exit, handle_sys_exit);
ltl_monitor_destroy();
}
static struct rv_monitor rv_wakeup = {
.name = "wakeup",
.description = "Monitor that real-time tasks are not woken by lower-priority tasks",
.enable = enable_wakeup,
.disable = disable_wakeup,
};
static int __init register_wakeup(void)
{
return rv_register_monitor(&rv_wakeup, &rv_rtapp);
}
static void __exit unregister_wakeup(void)
{
rv_unregister_monitor(&rv_wakeup);
}
module_init(register_wakeup);
module_exit(unregister_wakeup);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Nam Cao <namcao@linutronix.de>");
MODULE_DESCRIPTION("Monitor that real-time tasks are not woken by lower-priority tasks");
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