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
10 #define MODULE_NAME "opid"
11
12 #include <trace/events/sched.h>
13 #include <rv_trace.h>
14 #include <monitors/sched/sched.h>
15
16 #define RV_MON_TYPE RV_MON_PER_CPU
17 #include "opid.h"
18 #include <rv/ha_monitor.h>
19
ha_get_env(struct ha_monitor * ha_mon,enum envs_opid env,u64 time_ns)20 static u64 ha_get_env(struct ha_monitor *ha_mon, enum envs_opid env, u64 time_ns)
21 {
22 if (env == irq_off_opid)
23 return irqs_disabled();
24 else if (env == preempt_off_opid) {
25 /*
26 * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
27 * preemption (adding one to the preempt_count). Since we are
28 * interested in the preempt_count at the time the tracepoint was
29 * hit, we consider 1 as still enabled.
30 */
31 if (IS_ENABLED(CONFIG_PREEMPTION))
32 return (preempt_count() & PREEMPT_MASK) > 1;
33 return true;
34 }
35 return ENV_INVALID_VALUE;
36 }
37
ha_verify_guards(struct ha_monitor * ha_mon,enum states curr_state,enum events event,enum states next_state,u64 time_ns)38 static inline bool ha_verify_guards(struct ha_monitor *ha_mon,
39 enum states curr_state, enum events event,
40 enum states next_state, u64 time_ns)
41 {
42 bool res = true;
43
44 if (curr_state == any_opid && event == sched_need_resched_opid)
45 res = ha_get_env(ha_mon, irq_off_opid, time_ns) == 1ull;
46 else if (curr_state == any_opid && event == sched_waking_opid)
47 res = ha_get_env(ha_mon, irq_off_opid, time_ns) == 1ull &&
48 ha_get_env(ha_mon, preempt_off_opid, time_ns) == 1ull;
49 return res;
50 }
51
ha_verify_constraint(struct ha_monitor * ha_mon,enum states curr_state,enum events event,enum states next_state,u64 time_ns)52 static bool ha_verify_constraint(struct ha_monitor *ha_mon,
53 enum states curr_state, enum events event,
54 enum states next_state, u64 time_ns)
55 {
56 if (!ha_verify_guards(ha_mon, curr_state, event, next_state, time_ns))
57 return false;
58
59 return true;
60 }
61
handle_sched_need_resched(void * data,struct task_struct * tsk,int cpu,int tif)62 static void handle_sched_need_resched(void *data, struct task_struct *tsk, int cpu, int tif)
63 {
64 da_handle_start_run_event(sched_need_resched_opid);
65 }
66
handle_sched_waking(void * data,struct task_struct * p)67 static void handle_sched_waking(void *data, struct task_struct *p)
68 {
69 da_handle_start_run_event(sched_waking_opid);
70 }
71
enable_opid(void)72 static int enable_opid(void)
73 {
74 int retval;
75
76 retval = da_monitor_init();
77 if (retval)
78 return retval;
79
80 rv_attach_trace_probe("opid", sched_set_need_resched_tp, handle_sched_need_resched);
81 rv_attach_trace_probe("opid", sched_waking, handle_sched_waking);
82
83 return 0;
84 }
85
disable_opid(void)86 static void disable_opid(void)
87 {
88 rv_this.enabled = 0;
89
90 rv_detach_trace_probe("opid", sched_set_need_resched_tp, handle_sched_need_resched);
91 rv_detach_trace_probe("opid", sched_waking, handle_sched_waking);
92
93 da_monitor_destroy();
94 }
95
96 /*
97 * This is the monitor register section.
98 */
99 static struct rv_monitor rv_this = {
100 .name = "opid",
101 .description = "operations with preemption and irq disabled.",
102 .enable = enable_opid,
103 .disable = disable_opid,
104 .reset = da_monitor_reset_all,
105 .enabled = 0,
106 };
107
register_opid(void)108 static int __init register_opid(void)
109 {
110 return rv_register_monitor(&rv_this, &rv_sched);
111 }
112
unregister_opid(void)113 static void __exit unregister_opid(void)
114 {
115 rv_unregister_monitor(&rv_this);
116 }
117
118 module_init(register_opid);
119 module_exit(unregister_opid);
120
121 MODULE_LICENSE("GPL");
122 MODULE_AUTHOR("Gabriele Monaco <gmonaco@redhat.com>");
123 MODULE_DESCRIPTION("opid: operations with preemption and irq disabled.");
124