1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/ftrace.h>
3 #include <linux/tracepoint.h>
4 #include <linux/kernel.h>
5 #include <linux/module.h>
6 #include <linux/init.h>
7 #include <linux/rv.h>
8 #include <rv/instrumentation.h>
9 #include <rv/da_monitor.h>
10
11 #define MODULE_NAME "nrp"
12
13 #include <trace/events/irq.h>
14 #include <trace/events/sched.h>
15 #include <rv_trace.h>
16 #include <monitors/sched/sched.h>
17
18 #include "nrp.h"
19
20 static struct rv_monitor rv_nrp;
21 DECLARE_DA_MON_PER_TASK(nrp, unsigned char);
22
23 #ifdef CONFIG_X86_LOCAL_APIC
24 #include <asm/trace/irq_vectors.h>
25
handle_vector_irq_entry(void * data,int vector)26 static void handle_vector_irq_entry(void *data, int vector)
27 {
28 da_handle_event_nrp(current, irq_entry_nrp);
29 }
30
attach_vector_irq(void)31 static void attach_vector_irq(void)
32 {
33 rv_attach_trace_probe("nrp", local_timer_entry, handle_vector_irq_entry);
34 if (IS_ENABLED(CONFIG_IRQ_WORK))
35 rv_attach_trace_probe("nrp", irq_work_entry, handle_vector_irq_entry);
36 if (IS_ENABLED(CONFIG_SMP)) {
37 rv_attach_trace_probe("nrp", reschedule_entry, handle_vector_irq_entry);
38 rv_attach_trace_probe("nrp", call_function_entry, handle_vector_irq_entry);
39 rv_attach_trace_probe("nrp", call_function_single_entry, handle_vector_irq_entry);
40 }
41 }
42
detach_vector_irq(void)43 static void detach_vector_irq(void)
44 {
45 rv_detach_trace_probe("nrp", local_timer_entry, handle_vector_irq_entry);
46 if (IS_ENABLED(CONFIG_IRQ_WORK))
47 rv_detach_trace_probe("nrp", irq_work_entry, handle_vector_irq_entry);
48 if (IS_ENABLED(CONFIG_SMP)) {
49 rv_detach_trace_probe("nrp", reschedule_entry, handle_vector_irq_entry);
50 rv_detach_trace_probe("nrp", call_function_entry, handle_vector_irq_entry);
51 rv_detach_trace_probe("nrp", call_function_single_entry, handle_vector_irq_entry);
52 }
53 }
54
55 #else
56 /* We assume irq_entry tracepoints are sufficient on other architectures */
attach_vector_irq(void)57 static void attach_vector_irq(void) { }
detach_vector_irq(void)58 static void detach_vector_irq(void) { }
59 #endif
60
handle_irq_entry(void * data,int irq,struct irqaction * action)61 static void handle_irq_entry(void *data, int irq, struct irqaction *action)
62 {
63 da_handle_event_nrp(current, irq_entry_nrp);
64 }
65
handle_sched_need_resched(void * data,struct task_struct * tsk,int cpu,int tif)66 static void handle_sched_need_resched(void *data, struct task_struct *tsk,
67 int cpu, int tif)
68 {
69 /*
70 * Although need_resched leads to both the rescheduling and preempt_irq
71 * states, it is safer to start the monitor always in preempt_irq,
72 * which may not mirror the system state but makes the monitor simpler,
73 */
74 if (tif == TIF_NEED_RESCHED)
75 da_handle_start_event_nrp(tsk, sched_need_resched_nrp);
76 }
77
handle_schedule_entry(void * data,bool preempt)78 static void handle_schedule_entry(void *data, bool preempt)
79 {
80 if (preempt)
81 da_handle_event_nrp(current, schedule_entry_preempt_nrp);
82 else
83 da_handle_event_nrp(current, schedule_entry_nrp);
84 }
85
enable_nrp(void)86 static int enable_nrp(void)
87 {
88 int retval;
89
90 retval = da_monitor_init_nrp();
91 if (retval)
92 return retval;
93
94 rv_attach_trace_probe("nrp", irq_handler_entry, handle_irq_entry);
95 rv_attach_trace_probe("nrp", sched_set_need_resched_tp, handle_sched_need_resched);
96 rv_attach_trace_probe("nrp", sched_entry_tp, handle_schedule_entry);
97 attach_vector_irq();
98
99 return 0;
100 }
101
disable_nrp(void)102 static void disable_nrp(void)
103 {
104 rv_nrp.enabled = 0;
105
106 rv_detach_trace_probe("nrp", irq_handler_entry, handle_irq_entry);
107 rv_detach_trace_probe("nrp", sched_set_need_resched_tp, handle_sched_need_resched);
108 rv_detach_trace_probe("nrp", sched_entry_tp, handle_schedule_entry);
109 detach_vector_irq();
110
111 da_monitor_destroy_nrp();
112 }
113
114 static struct rv_monitor rv_nrp = {
115 .name = "nrp",
116 .description = "need resched preempts.",
117 .enable = enable_nrp,
118 .disable = disable_nrp,
119 .reset = da_monitor_reset_all_nrp,
120 .enabled = 0,
121 };
122
register_nrp(void)123 static int __init register_nrp(void)
124 {
125 return rv_register_monitor(&rv_nrp, &rv_sched);
126 }
127
unregister_nrp(void)128 static void __exit unregister_nrp(void)
129 {
130 rv_unregister_monitor(&rv_nrp);
131 }
132
133 module_init(register_nrp);
134 module_exit(unregister_nrp);
135
136 MODULE_LICENSE("GPL");
137 MODULE_AUTHOR("Gabriele Monaco <gmonaco@redhat.com>");
138 MODULE_DESCRIPTION("nrp: need resched preempts.");
139