4 files changed, 167 insertions, 0 deletions
diff --git a/kernel/trace/rv/monitors/tss/Kconfig b/kernel/trace/rv/monitors/tss/Kconfig
new file mode 100644
index 000000000000..479f86f52e60
--- /dev/null
+++ b/kernel/trace/rv/monitors/tss/Kconfig
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+config RV_MON_TSS
+	depends on RV
+	depends on RV_MON_SCHED
+	default y
+	select DA_MON_EVENTS_IMPLICIT
+	bool "tss monitor"
+	help
+	  Monitor to ensure sched_switch happens only in scheduling context.
+	  This monitor is part of the sched monitors collection.
+
+	  For further information, see:
+	    Documentation/trace/rv/monitor_sched.rst
diff --git a/kernel/trace/rv/monitors/tss/tss.c b/kernel/trace/rv/monitors/tss/tss.c
new file mode 100644
index 000000000000..542787e6524f
--- /dev/null
+++ b/kernel/trace/rv/monitors/tss/tss.c
@@ -0,0 +1,91 @@
+// 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>
+#include <rv/da_monitor.h>
+
+#define MODULE_NAME "tss"
+
+#include <trace/events/sched.h>
+#include <rv_trace.h>
+#include <monitors/sched/sched.h>
+
+#include "tss.h"
+
+static struct rv_monitor rv_tss;
+DECLARE_DA_MON_PER_CPU(tss, unsigned char);
+
+static void handle_sched_switch(void *data, bool preempt,
+				struct task_struct *prev,
+				struct task_struct *next,
+				unsigned int prev_state)
+{
+	da_handle_event_tss(sched_switch_tss);
+}
+
+static void handle_schedule_entry(void *data, bool preempt, unsigned long ip)
+{
+	da_handle_event_tss(schedule_entry_tss);
+}
+
+static void handle_schedule_exit(void *data, bool is_switch, unsigned long ip)
+{
+	da_handle_start_event_tss(schedule_exit_tss);
+}
+
+static int enable_tss(void)
+{
+	int retval;
+
+	retval = da_monitor_init_tss();
+	if (retval)
+		return retval;
+
+	rv_attach_trace_probe("tss", sched_switch, handle_sched_switch);
+	rv_attach_trace_probe("tss", sched_entry_tp, handle_schedule_entry);
+	rv_attach_trace_probe("tss", sched_exit_tp, handle_schedule_exit);
+
+	return 0;
+}
+
+static void disable_tss(void)
+{
+	rv_tss.enabled = 0;
+
+	rv_detach_trace_probe("tss", sched_switch, handle_sched_switch);
+	rv_detach_trace_probe("tss", sched_entry_tp, handle_schedule_entry);
+	rv_detach_trace_probe("tss", sched_exit_tp, handle_schedule_exit);
+
+	da_monitor_destroy_tss();
+}
+
+static struct rv_monitor rv_tss = {
+	.name = "tss",
+	.description = "task switch while scheduling.",
+	.enable = enable_tss,
+	.disable = disable_tss,
+	.reset = da_monitor_reset_all_tss,
+	.enabled = 0,
+};
+
+static int __init register_tss(void)
+{
+	rv_register_monitor(&rv_tss, &rv_sched);
+	return 0;
+}
+
+static void __exit unregister_tss(void)
+{
+	rv_unregister_monitor(&rv_tss);
+}
+
+module_init(register_tss);
+module_exit(unregister_tss);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Gabriele Monaco <gmonaco@redhat.com>");
+MODULE_DESCRIPTION("tss: task switch while scheduling.");
diff --git a/kernel/trace/rv/monitors/tss/tss.h b/kernel/trace/rv/monitors/tss/tss.h
new file mode 100644
index 000000000000..f0a36fda1b87
--- /dev/null
+++ b/kernel/trace/rv/monitors/tss/tss.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Automatically generated C representation of tss automaton
+ * For further information about this format, see kernel documentation:
+ *   Documentation/trace/rv/deterministic_automata.rst
+ */
+
+enum states_tss {
+	thread_tss = 0,
+	sched_tss,
+	state_max_tss
+};
+
+#define INVALID_STATE state_max_tss
+
+enum events_tss {
+	sched_switch_tss = 0,
+	schedule_entry_tss,
+	schedule_exit_tss,
+	event_max_tss
+};
+
+struct automaton_tss {
+	char *state_names[state_max_tss];
+	char *event_names[event_max_tss];
+	unsigned char function[state_max_tss][event_max_tss];
+	unsigned char initial_state;
+	bool final_states[state_max_tss];
+};
+
+static const struct automaton_tss automaton_tss = {
+	.state_names = {
+		"thread",
+		"sched"
+	},
+	.event_names = {
+		"sched_switch",
+		"schedule_entry",
+		"schedule_exit"
+	},
+	.function = {
+		{     INVALID_STATE,         sched_tss,     INVALID_STATE },
+		{         sched_tss,     INVALID_STATE,        thread_tss },
+	},
+	.initial_state = thread_tss,
+	.final_states = { 1, 0 },
+};
diff --git a/kernel/trace/rv/monitors/tss/tss_trace.h b/kernel/trace/rv/monitors/tss/tss_trace.h
new file mode 100644
index 000000000000..4619dbb50cc0
--- /dev/null
+++ b/kernel/trace/rv/monitors/tss/tss_trace.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Snippet to be included in rv_trace.h
+ */
+
+#ifdef CONFIG_RV_MON_TSS
+DEFINE_EVENT(event_da_monitor, event_tss,
+	     TP_PROTO(char *state, char *event, char *next_state, bool final_state),
+	     TP_ARGS(state, event, next_state, final_state));
+
+DEFINE_EVENT(error_da_monitor, error_tss,
+	     TP_PROTO(char *state, char *event),
+	     TP_ARGS(state, event));
+#endif /* CONFIG_RV_MON_TSS */