rv: Add nrp and sssw per-task monitors

Add 2 per-task monitors as part of the sched model:

* nrp: need-resched preempts
    Monitor to ensure preemption requires need resched.
* sssw: set state sleep and wakeup
    Monitor to ensure sched_set_state to sleepable leads to sleeping and
    sleeping tasks require wakeup.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20250728135022.255578-9-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Acked-by: Nam Cao <namcao@linutronix.de>
Tested-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

12 files changed, 502 insertions, 0 deletions

diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index b688b24081c8..59d0db898d4a 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -55,6 +55,8 @@ source "kernel/trace/rv/monitors/snroc/Kconfig"
 source "kernel/trace/rv/monitors/scpd/Kconfig"
 source "kernel/trace/rv/monitors/snep/Kconfig"
 source "kernel/trace/rv/monitors/sts/Kconfig"
+source "kernel/trace/rv/monitors/nrp/Kconfig"
+source "kernel/trace/rv/monitors/sssw/Kconfig"
 # Add new sched monitors here
 
 source "kernel/trace/rv/monitors/rtapp/Kconfig"
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
index 1939d3d7621c..2afac88539d3 100644
--- a/kernel/trace/rv/Makefile
+++ b/kernel/trace/rv/Makefile
@@ -14,6 +14,8 @@ obj-$(CONFIG_RV_MON_RTAPP) += monitors/rtapp/rtapp.o
 obj-$(CONFIG_RV_MON_PAGEFAULT) += monitors/pagefault/pagefault.o
 obj-$(CONFIG_RV_MON_SLEEP) += monitors/sleep/sleep.o
 obj-$(CONFIG_RV_MON_STS) += monitors/sts/sts.o
+obj-$(CONFIG_RV_MON_NRP) += monitors/nrp/nrp.o
+obj-$(CONFIG_RV_MON_SSSW) += monitors/sssw/sssw.o
 # Add new monitors here
 obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
 obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o
diff --git a/kernel/trace/rv/monitors/nrp/Kconfig b/kernel/trace/rv/monitors/nrp/Kconfig
new file mode 100644
index 000000000000..f5ec08f65535
--- /dev/null
+++ b/kernel/trace/rv/monitors/nrp/Kconfig
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+config RV_MON_NRP
+	depends on RV
+	depends on RV_MON_SCHED
+	default y if !ARM64
+	select DA_MON_EVENTS_ID
+	bool "nrp monitor"
+	help
+	  Monitor to ensure preemption requires need resched.
+	  This monitor is part of the sched monitors collection.
+
+	  This monitor is unstable on arm64, say N unless you are testing it.
+
+	  For further information, see:
+	    Documentation/trace/rv/monitor_sched.rst
diff --git a/kernel/trace/rv/monitors/nrp/nrp.c b/kernel/trace/rv/monitors/nrp/nrp.c
new file mode 100644
index 000000000000..5a83b7171432
--- /dev/null
+++ b/kernel/trace/rv/monitors/nrp/nrp.c
@@ -0,0 +1,138 @@
+// 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 "nrp"
+
+#include <trace/events/irq.h>
+#include <trace/events/sched.h>
+#include <rv_trace.h>
+#include <monitors/sched/sched.h>
+
+#include "nrp.h"
+
+static struct rv_monitor rv_nrp;
+DECLARE_DA_MON_PER_TASK(nrp, unsigned char);
+
+#ifdef CONFIG_X86_LOCAL_APIC
+#include <asm/trace/irq_vectors.h>
+
+static void handle_vector_irq_entry(void *data, int vector)
+{
+	da_handle_event_nrp(current, irq_entry_nrp);
+}
+
+static void attach_vector_irq(void)
+{
+	rv_attach_trace_probe("nrp", local_timer_entry, handle_vector_irq_entry);
+	if (IS_ENABLED(CONFIG_IRQ_WORK))
+		rv_attach_trace_probe("nrp", irq_work_entry, handle_vector_irq_entry);
+	if (IS_ENABLED(CONFIG_SMP)) {
+		rv_attach_trace_probe("nrp", reschedule_entry, handle_vector_irq_entry);
+		rv_attach_trace_probe("nrp", call_function_entry, handle_vector_irq_entry);
+		rv_attach_trace_probe("nrp", call_function_single_entry, handle_vector_irq_entry);
+	}
+}
+
+static void detach_vector_irq(void)
+{
+	rv_detach_trace_probe("nrp", local_timer_entry, handle_vector_irq_entry);
+	if (IS_ENABLED(CONFIG_IRQ_WORK))
+		rv_detach_trace_probe("nrp", irq_work_entry, handle_vector_irq_entry);
+	if (IS_ENABLED(CONFIG_SMP)) {
+		rv_detach_trace_probe("nrp", reschedule_entry, handle_vector_irq_entry);
+		rv_detach_trace_probe("nrp", call_function_entry, handle_vector_irq_entry);
+		rv_detach_trace_probe("nrp", call_function_single_entry, handle_vector_irq_entry);
+	}
+}
+
+#else
+/* We assume irq_entry tracepoints are sufficient on other architectures */
+static void attach_vector_irq(void) { }
+static void detach_vector_irq(void) { }
+#endif
+
+static void handle_irq_entry(void *data, int irq, struct irqaction *action)
+{
+	da_handle_event_nrp(current, irq_entry_nrp);
+}
+
+static void handle_sched_need_resched(void *data, struct task_struct *tsk,
+				      int cpu, int tif)
+{
+	/*
+	 * Although need_resched leads to both the rescheduling and preempt_irq
+	 * states, it is safer to start the monitor always in preempt_irq,
+	 * which may not mirror the system state but makes the monitor simpler,
+	 */
+	if (tif == TIF_NEED_RESCHED)
+		da_handle_start_event_nrp(tsk, sched_need_resched_nrp);
+}
+
+static void handle_schedule_entry(void *data, bool preempt)
+{
+	if (preempt)
+		da_handle_event_nrp(current, schedule_entry_preempt_nrp);
+	else
+		da_handle_event_nrp(current, schedule_entry_nrp);
+}
+
+static int enable_nrp(void)
+{
+	int retval;
+
+	retval = da_monitor_init_nrp();
+	if (retval)
+		return retval;
+
+	rv_attach_trace_probe("nrp", irq_handler_entry, handle_irq_entry);
+	rv_attach_trace_probe("nrp", sched_set_need_resched_tp, handle_sched_need_resched);
+	rv_attach_trace_probe("nrp", sched_entry_tp, handle_schedule_entry);
+	attach_vector_irq();
+
+	return 0;
+}
+
+static void disable_nrp(void)
+{
+	rv_nrp.enabled = 0;
+
+	rv_detach_trace_probe("nrp", irq_handler_entry, handle_irq_entry);
+	rv_detach_trace_probe("nrp", sched_set_need_resched_tp, handle_sched_need_resched);
+	rv_detach_trace_probe("nrp", sched_entry_tp, handle_schedule_entry);
+	detach_vector_irq();
+
+	da_monitor_destroy_nrp();
+}
+
+static struct rv_monitor rv_nrp = {
+	.name = "nrp",
+	.description = "need resched preempts.",
+	.enable = enable_nrp,
+	.disable = disable_nrp,
+	.reset = da_monitor_reset_all_nrp,
+	.enabled = 0,
+};
+
+static int __init register_nrp(void)
+{
+	return rv_register_monitor(&rv_nrp, &rv_sched);
+}
+
+static void __exit unregister_nrp(void)
+{
+	rv_unregister_monitor(&rv_nrp);
+}
+
+module_init(register_nrp);
+module_exit(unregister_nrp);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Gabriele Monaco <gmonaco@redhat.com>");
+MODULE_DESCRIPTION("nrp: need resched preempts.");
diff --git a/kernel/trace/rv/monitors/nrp/nrp.h b/kernel/trace/rv/monitors/nrp/nrp.h
new file mode 100644
index 000000000000..c9f12207cbf6
--- /dev/null
+++ b/kernel/trace/rv/monitors/nrp/nrp.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Automatically generated C representation of nrp automaton
+ * For further information about this format, see kernel documentation:
+ *   Documentation/trace/rv/deterministic_automata.rst
+ */
+
+enum states_nrp {
+	preempt_irq_nrp = 0,
+	any_thread_running_nrp,
+	nested_preempt_nrp,
+	rescheduling_nrp,
+	state_max_nrp
+};
+
+#define INVALID_STATE state_max_nrp
+
+enum events_nrp {
+	irq_entry_nrp = 0,
+	sched_need_resched_nrp,
+	schedule_entry_nrp,
+	schedule_entry_preempt_nrp,
+	event_max_nrp
+};
+
+struct automaton_nrp {
+	char *state_names[state_max_nrp];
+	char *event_names[event_max_nrp];
+	unsigned char function[state_max_nrp][event_max_nrp];
+	unsigned char initial_state;
+	bool final_states[state_max_nrp];
+};
+
+static const struct automaton_nrp automaton_nrp = {
+	.state_names = {
+		"preempt_irq",
+		"any_thread_running",
+		"nested_preempt",
+		"rescheduling"
+	},
+	.event_names = {
+		"irq_entry",
+		"sched_need_resched",
+		"schedule_entry",
+		"schedule_entry_preempt"
+	},
+	.function = {
+		{
+			preempt_irq_nrp,
+			preempt_irq_nrp,
+			nested_preempt_nrp,
+			nested_preempt_nrp
+		},
+		{
+			any_thread_running_nrp,
+			rescheduling_nrp,
+			any_thread_running_nrp,
+			INVALID_STATE
+		},
+		{
+			nested_preempt_nrp,
+			preempt_irq_nrp,
+			any_thread_running_nrp,
+			any_thread_running_nrp
+		},
+		{
+			preempt_irq_nrp,
+			rescheduling_nrp,
+			any_thread_running_nrp,
+			any_thread_running_nrp
+		},
+	},
+	.initial_state = preempt_irq_nrp,
+	.final_states = { 0, 1, 0, 0 },
+};
diff --git a/kernel/trace/rv/monitors/nrp/nrp_trace.h b/kernel/trace/rv/monitors/nrp/nrp_trace.h
new file mode 100644
index 000000000000..2e13497de3b6
--- /dev/null
+++ b/kernel/trace/rv/monitors/nrp/nrp_trace.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Snippet to be included in rv_trace.h
+ */
+
+#ifdef CONFIG_RV_MON_NRP
+DEFINE_EVENT(event_da_monitor_id, event_nrp,
+	     TP_PROTO(int id, char *state, char *event, char *next_state, bool final_state),
+	     TP_ARGS(id, state, event, next_state, final_state));
+
+DEFINE_EVENT(error_da_monitor_id, error_nrp,
+	     TP_PROTO(int id, char *state, char *event),
+	     TP_ARGS(id, state, event));
+#endif /* CONFIG_RV_MON_NRP */
diff --git a/kernel/trace/rv/monitors/sched/Kconfig b/kernel/trace/rv/monitors/sched/Kconfig
index ae3eb410abd7..aa16456da864 100644
--- a/kernel/trace/rv/monitors/sched/Kconfig
+++ b/kernel/trace/rv/monitors/sched/Kconfig
@@ -2,6 +2,7 @@
 #
 config RV_MON_SCHED
 	depends on RV
+	depends on RV_PER_TASK_MONITORS >= 3
 	bool "sched monitor"
 	help
 	  Collection of monitors to check the scheduler behaves according to specifications.
diff --git a/kernel/trace/rv/monitors/sssw/Kconfig b/kernel/trace/rv/monitors/sssw/Kconfig
new file mode 100644
index 000000000000..23b7eeb38bbf
--- /dev/null
+++ b/kernel/trace/rv/monitors/sssw/Kconfig
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+config RV_MON_SSSW
+	depends on RV
+	depends on RV_MON_SCHED
+	default y
+	select DA_MON_EVENTS_ID
+	bool "sssw monitor"
+	help
+	  Monitor to ensure sched_set_state to sleepable leads to sleeping and
+	  sleeping tasks require wakeup.
+	  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/sssw/sssw.c b/kernel/trace/rv/monitors/sssw/sssw.c
new file mode 100644
index 000000000000..84b8d890d9d4
--- /dev/null
+++ b/kernel/trace/rv/monitors/sssw/sssw.c
@@ -0,0 +1,116 @@
+// 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 "sssw"
+
+#include <trace/events/sched.h>
+#include <trace/events/signal.h>
+#include <rv_trace.h>
+#include <monitors/sched/sched.h>
+
+#include "sssw.h"
+
+static struct rv_monitor rv_sssw;
+DECLARE_DA_MON_PER_TASK(sssw, unsigned char);
+
+static void handle_sched_set_state(void *data, struct task_struct *tsk, int state)
+{
+	if (state == TASK_RUNNING)
+		da_handle_start_event_sssw(tsk, sched_set_state_runnable_sssw);
+	else
+		da_handle_event_sssw(tsk, sched_set_state_sleepable_sssw);
+}
+
+static void handle_sched_switch(void *data, bool preempt,
+				struct task_struct *prev,
+				struct task_struct *next,
+				unsigned int prev_state)
+{
+	if (preempt)
+		da_handle_event_sssw(prev, sched_switch_preempt_sssw);
+	else if (prev_state == TASK_RUNNING)
+		da_handle_event_sssw(prev, sched_switch_yield_sssw);
+	else if (prev_state == TASK_RTLOCK_WAIT)
+		/* special case of sleeping task with racy conditions */
+		da_handle_event_sssw(prev, sched_switch_blocking_sssw);
+	else
+		da_handle_event_sssw(prev, sched_switch_suspend_sssw);
+	da_handle_event_sssw(next, sched_switch_in_sssw);
+}
+
+static void handle_sched_wakeup(void *data, struct task_struct *p)
+{
+	/*
+	 * Wakeup can also lead to signal_wakeup although the system is
+	 * actually runnable. The monitor can safely start with this event.
+	 */
+	da_handle_start_event_sssw(p, sched_wakeup_sssw);
+}
+
+static void handle_signal_deliver(void *data, int sig,
+				   struct kernel_siginfo *info,
+				   struct k_sigaction *ka)
+{
+	da_handle_event_sssw(current, signal_deliver_sssw);
+}
+
+static int enable_sssw(void)
+{
+	int retval;
+
+	retval = da_monitor_init_sssw();
+	if (retval)
+		return retval;
+
+	rv_attach_trace_probe("sssw", sched_set_state_tp, handle_sched_set_state);
+	rv_attach_trace_probe("sssw", sched_switch, handle_sched_switch);
+	rv_attach_trace_probe("sssw", sched_wakeup, handle_sched_wakeup);
+	rv_attach_trace_probe("sssw", signal_deliver, handle_signal_deliver);
+
+	return 0;
+}
+
+static void disable_sssw(void)
+{
+	rv_sssw.enabled = 0;
+
+	rv_detach_trace_probe("sssw", sched_set_state_tp, handle_sched_set_state);
+	rv_detach_trace_probe("sssw", sched_switch, handle_sched_switch);
+	rv_detach_trace_probe("sssw", sched_wakeup, handle_sched_wakeup);
+	rv_detach_trace_probe("sssw", signal_deliver, handle_signal_deliver);
+
+	da_monitor_destroy_sssw();
+}
+
+static struct rv_monitor rv_sssw = {
+	.name = "sssw",
+	.description = "set state sleep and wakeup.",
+	.enable = enable_sssw,
+	.disable = disable_sssw,
+	.reset = da_monitor_reset_all_sssw,
+	.enabled = 0,
+};
+
+static int __init register_sssw(void)
+{
+	return rv_register_monitor(&rv_sssw, &rv_sched);
+}
+
+static void __exit unregister_sssw(void)
+{
+	rv_unregister_monitor(&rv_sssw);
+}
+
+module_init(register_sssw);
+module_exit(unregister_sssw);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Gabriele Monaco <gmonaco@redhat.com>");
+MODULE_DESCRIPTION("sssw: set state sleep and wakeup.");
diff --git a/kernel/trace/rv/monitors/sssw/sssw.h b/kernel/trace/rv/monitors/sssw/sssw.h
new file mode 100644
index 000000000000..243d54050c94
--- /dev/null
+++ b/kernel/trace/rv/monitors/sssw/sssw.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Automatically generated C representation of sssw automaton
+ * For further information about this format, see kernel documentation:
+ *   Documentation/trace/rv/deterministic_automata.rst
+ */
+
+enum states_sssw {
+	runnable_sssw = 0,
+	signal_wakeup_sssw,
+	sleepable_sssw,
+	sleeping_sssw,
+	state_max_sssw
+};
+
+#define INVALID_STATE state_max_sssw
+
+enum events_sssw {
+	sched_set_state_runnable_sssw = 0,
+	sched_set_state_sleepable_sssw,
+	sched_switch_blocking_sssw,
+	sched_switch_in_sssw,
+	sched_switch_preempt_sssw,
+	sched_switch_suspend_sssw,
+	sched_switch_yield_sssw,
+	sched_wakeup_sssw,
+	signal_deliver_sssw,
+	event_max_sssw
+};
+
+struct automaton_sssw {
+	char *state_names[state_max_sssw];
+	char *event_names[event_max_sssw];
+	unsigned char function[state_max_sssw][event_max_sssw];
+	unsigned char initial_state;
+	bool final_states[state_max_sssw];
+};
+
+static const struct automaton_sssw automaton_sssw = {
+	.state_names = {
+		"runnable",
+		"signal_wakeup",
+		"sleepable",
+		"sleeping"
+	},
+	.event_names = {
+		"sched_set_state_runnable",
+		"sched_set_state_sleepable",
+		"sched_switch_blocking",
+		"sched_switch_in",
+		"sched_switch_preempt",
+		"sched_switch_suspend",
+		"sched_switch_yield",
+		"sched_wakeup",
+		"signal_deliver"
+	},
+	.function = {
+		{
+			runnable_sssw,
+			sleepable_sssw,
+			sleeping_sssw,
+			runnable_sssw,
+			runnable_sssw,
+			INVALID_STATE,
+			runnable_sssw,
+			runnable_sssw,
+			runnable_sssw
+		},
+		{
+			INVALID_STATE,
+			sleepable_sssw,
+			INVALID_STATE,
+			signal_wakeup_sssw,
+			signal_wakeup_sssw,
+			INVALID_STATE,
+			signal_wakeup_sssw,
+			signal_wakeup_sssw,
+			runnable_sssw
+		},
+		{
+			runnable_sssw,
+			sleepable_sssw,
+			sleeping_sssw,
+			sleepable_sssw,
+			sleepable_sssw,
+			sleeping_sssw,
+			signal_wakeup_sssw,
+			runnable_sssw,
+			sleepable_sssw
+		},
+		{
+			INVALID_STATE,
+			INVALID_STATE,
+			INVALID_STATE,
+			INVALID_STATE,
+			INVALID_STATE,
+			INVALID_STATE,
+			INVALID_STATE,
+			runnable_sssw,
+			INVALID_STATE
+		},
+	},
+	.initial_state = runnable_sssw,
+	.final_states = { 1, 0, 0, 0 },
+};
diff --git a/kernel/trace/rv/monitors/sssw/sssw_trace.h b/kernel/trace/rv/monitors/sssw/sssw_trace.h
new file mode 100644
index 000000000000..6c03cfc6960b
--- /dev/null
+++ b/kernel/trace/rv/monitors/sssw/sssw_trace.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Snippet to be included in rv_trace.h
+ */
+
+#ifdef CONFIG_RV_MON_SSSW
+DEFINE_EVENT(event_da_monitor_id, event_sssw,
+	     TP_PROTO(int id, char *state, char *event, char *next_state, bool final_state),
+	     TP_ARGS(id, state, event, next_state, final_state));
+
+DEFINE_EVENT(error_da_monitor_id, error_sssw,
+	     TP_PROTO(int id, char *state, char *event),
+	     TP_ARGS(id, state, event));
+#endif /* CONFIG_RV_MON_SSSW */
diff --git a/kernel/trace/rv/rv_trace.h b/kernel/trace/rv/rv_trace.h
index 97b2f7e07f27..e4e78d23b7b0 100644
--- a/kernel/trace/rv/rv_trace.h
+++ b/kernel/trace/rv/rv_trace.h
@@ -123,6 +123,8 @@ DECLARE_EVENT_CLASS(error_da_monitor_id,
 
 #include <monitors/wwnr/wwnr_trace.h>
 #include <monitors/snroc/snroc_trace.h>
+#include <monitors/nrp/nrp_trace.h>
+#include <monitors/sssw/sssw_trace.h>
 // Add new monitors based on CONFIG_DA_MON_EVENTS_ID here
 
 #endif /* CONFIG_DA_MON_EVENTS_ID */