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-rw-r--r--kernel/trace/rv/Kconfig78
-rw-r--r--kernel/trace/rv/Makefile8
-rw-r--r--kernel/trace/rv/monitors/wip/wip.c88
-rw-r--r--kernel/trace/rv/monitors/wip/wip.h46
-rw-r--r--kernel/trace/rv/monitors/wwnr/wwnr.c87
-rw-r--r--kernel/trace/rv/monitors/wwnr/wwnr.h46
-rw-r--r--kernel/trace/rv/reactor_panic.c42
-rw-r--r--kernel/trace/rv/reactor_printk.c41
-rw-r--r--kernel/trace/rv/rv.c797
-rw-r--r--kernel/trace/rv/rv.h68
-rw-r--r--kernel/trace/rv/rv_reactors.c510
11 files changed, 1811 insertions, 0 deletions
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
new file mode 100644
index 0000000000..831779607e
--- /dev/null
+++ b/kernel/trace/rv/Kconfig
@@ -0,0 +1,78 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+config DA_MON_EVENTS
+ bool
+
+config DA_MON_EVENTS_IMPLICIT
+ select DA_MON_EVENTS
+ bool
+
+config DA_MON_EVENTS_ID
+ select DA_MON_EVENTS
+ bool
+
+menuconfig RV
+ bool "Runtime Verification"
+ depends on TRACING
+ help
+ Enable the kernel runtime verification infrastructure. RV is a
+ lightweight (yet rigorous) method that complements classical
+ exhaustive verification techniques (such as model checking and
+ theorem proving). RV works by analyzing the trace of the system's
+ actual execution, comparing it against a formal specification of
+ the system behavior.
+
+ For further information, see:
+ Documentation/trace/rv/runtime-verification.rst
+
+config RV_MON_WIP
+ depends on RV
+ depends on PREEMPT_TRACER
+ select DA_MON_EVENTS_IMPLICIT
+ bool "wip monitor"
+ help
+ Enable wip (wakeup in preemptive) sample monitor that illustrates
+ the usage of per-cpu monitors, and one limitation of the
+ preempt_disable/enable events.
+
+ For further information, see:
+ Documentation/trace/rv/monitor_wip.rst
+
+config RV_MON_WWNR
+ depends on RV
+ select DA_MON_EVENTS_ID
+ bool "wwnr monitor"
+ help
+ Enable wwnr (wakeup while not running) sample monitor, this is a
+ sample monitor that illustrates the usage of per-task monitor.
+ The model is borken on purpose: it serves to test reactors.
+
+ For further information, see:
+ Documentation/trace/rv/monitor_wwnr.rst
+
+config RV_REACTORS
+ bool "Runtime verification reactors"
+ default y
+ depends on RV
+ help
+ Enables the online runtime verification reactors. A runtime
+ monitor can cause a reaction to the detection of an exception
+ on the model's execution. By default, the monitors have
+ tracing reactions, printing the monitor output via tracepoints,
+ but other reactions can be added (on-demand) via this interface.
+
+config RV_REACT_PRINTK
+ bool "Printk reactor"
+ depends on RV_REACTORS
+ default y
+ help
+ Enables the printk reactor. The printk reactor emits a printk()
+ message if an exception is found.
+
+config RV_REACT_PANIC
+ bool "Panic reactor"
+ depends on RV_REACTORS
+ default y
+ help
+ Enables the panic reactor. The panic reactor emits a printk()
+ message if an exception is found and panic()s the system.
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
new file mode 100644
index 0000000000..963d14875b
--- /dev/null
+++ b/kernel/trace/rv/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_RV) += rv.o
+obj-$(CONFIG_RV_MON_WIP) += monitors/wip/wip.o
+obj-$(CONFIG_RV_MON_WWNR) += monitors/wwnr/wwnr.o
+obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
+obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o
+obj-$(CONFIG_RV_REACT_PANIC) += reactor_panic.o
diff --git a/kernel/trace/rv/monitors/wip/wip.c b/kernel/trace/rv/monitors/wip/wip.c
new file mode 100644
index 0000000000..b2b49a27e8
--- /dev/null
+++ b/kernel/trace/rv/monitors/wip/wip.c
@@ -0,0 +1,88 @@
+// 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 "wip"
+
+#include <trace/events/rv.h>
+#include <trace/events/sched.h>
+#include <trace/events/preemptirq.h>
+
+#include "wip.h"
+
+static struct rv_monitor rv_wip;
+DECLARE_DA_MON_PER_CPU(wip, unsigned char);
+
+static void handle_preempt_disable(void *data, unsigned long ip, unsigned long parent_ip)
+{
+ da_handle_event_wip(preempt_disable_wip);
+}
+
+static void handle_preempt_enable(void *data, unsigned long ip, unsigned long parent_ip)
+{
+ da_handle_start_event_wip(preempt_enable_wip);
+}
+
+static void handle_sched_waking(void *data, struct task_struct *task)
+{
+ da_handle_event_wip(sched_waking_wip);
+}
+
+static int enable_wip(void)
+{
+ int retval;
+
+ retval = da_monitor_init_wip();
+ if (retval)
+ return retval;
+
+ rv_attach_trace_probe("wip", preempt_enable, handle_preempt_enable);
+ rv_attach_trace_probe("wip", sched_waking, handle_sched_waking);
+ rv_attach_trace_probe("wip", preempt_disable, handle_preempt_disable);
+
+ return 0;
+}
+
+static void disable_wip(void)
+{
+ rv_wip.enabled = 0;
+
+ rv_detach_trace_probe("wip", preempt_disable, handle_preempt_disable);
+ rv_detach_trace_probe("wip", preempt_enable, handle_preempt_enable);
+ rv_detach_trace_probe("wip", sched_waking, handle_sched_waking);
+
+ da_monitor_destroy_wip();
+}
+
+static struct rv_monitor rv_wip = {
+ .name = "wip",
+ .description = "wakeup in preemptive per-cpu testing monitor.",
+ .enable = enable_wip,
+ .disable = disable_wip,
+ .reset = da_monitor_reset_all_wip,
+ .enabled = 0,
+};
+
+static int __init register_wip(void)
+{
+ rv_register_monitor(&rv_wip);
+ return 0;
+}
+
+static void __exit unregister_wip(void)
+{
+ rv_unregister_monitor(&rv_wip);
+}
+
+module_init(register_wip);
+module_exit(unregister_wip);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira <bristot@kernel.org>");
+MODULE_DESCRIPTION("wip: wakeup in preemptive - per-cpu sample monitor.");
diff --git a/kernel/trace/rv/monitors/wip/wip.h b/kernel/trace/rv/monitors/wip/wip.h
new file mode 100644
index 0000000000..2e373f2c65
--- /dev/null
+++ b/kernel/trace/rv/monitors/wip/wip.h
@@ -0,0 +1,46 @@
+/*
+ * Automatically generated C representation of wip automaton
+ * For further information about this format, see kernel documentation:
+ * Documentation/trace/rv/deterministic_automata.rst
+ */
+
+enum states_wip {
+ preemptive_wip = 0,
+ non_preemptive_wip,
+ state_max_wip
+};
+
+#define INVALID_STATE state_max_wip
+
+enum events_wip {
+ preempt_disable_wip = 0,
+ preempt_enable_wip,
+ sched_waking_wip,
+ event_max_wip
+};
+
+struct automaton_wip {
+ char *state_names[state_max_wip];
+ char *event_names[event_max_wip];
+ unsigned char function[state_max_wip][event_max_wip];
+ unsigned char initial_state;
+ bool final_states[state_max_wip];
+};
+
+static const struct automaton_wip automaton_wip = {
+ .state_names = {
+ "preemptive",
+ "non_preemptive"
+ },
+ .event_names = {
+ "preempt_disable",
+ "preempt_enable",
+ "sched_waking"
+ },
+ .function = {
+ { non_preemptive_wip, INVALID_STATE, INVALID_STATE },
+ { INVALID_STATE, preemptive_wip, non_preemptive_wip },
+ },
+ .initial_state = preemptive_wip,
+ .final_states = { 1, 0 },
+};
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.c b/kernel/trace/rv/monitors/wwnr/wwnr.c
new file mode 100644
index 0000000000..0e43dd2db6
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.c
@@ -0,0 +1,87 @@
+// 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 "wwnr"
+
+#include <trace/events/rv.h>
+#include <trace/events/sched.h>
+
+#include "wwnr.h"
+
+static struct rv_monitor rv_wwnr;
+DECLARE_DA_MON_PER_TASK(wwnr, unsigned char);
+
+static void handle_switch(void *data, bool preempt, struct task_struct *p,
+ struct task_struct *n, unsigned int prev_state)
+{
+ /* start monitoring only after the first suspension */
+ if (prev_state == TASK_INTERRUPTIBLE)
+ da_handle_start_event_wwnr(p, switch_out_wwnr);
+ else
+ da_handle_event_wwnr(p, switch_out_wwnr);
+
+ da_handle_event_wwnr(n, switch_in_wwnr);
+}
+
+static void handle_wakeup(void *data, struct task_struct *p)
+{
+ da_handle_event_wwnr(p, wakeup_wwnr);
+}
+
+static int enable_wwnr(void)
+{
+ int retval;
+
+ retval = da_monitor_init_wwnr();
+ if (retval)
+ return retval;
+
+ rv_attach_trace_probe("wwnr", sched_switch, handle_switch);
+ rv_attach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
+
+ return 0;
+}
+
+static void disable_wwnr(void)
+{
+ rv_wwnr.enabled = 0;
+
+ rv_detach_trace_probe("wwnr", sched_switch, handle_switch);
+ rv_detach_trace_probe("wwnr", sched_wakeup, handle_wakeup);
+
+ da_monitor_destroy_wwnr();
+}
+
+static struct rv_monitor rv_wwnr = {
+ .name = "wwnr",
+ .description = "wakeup while not running per-task testing model.",
+ .enable = enable_wwnr,
+ .disable = disable_wwnr,
+ .reset = da_monitor_reset_all_wwnr,
+ .enabled = 0,
+};
+
+static int __init register_wwnr(void)
+{
+ rv_register_monitor(&rv_wwnr);
+ return 0;
+}
+
+static void __exit unregister_wwnr(void)
+{
+ rv_unregister_monitor(&rv_wwnr);
+}
+
+module_init(register_wwnr);
+module_exit(unregister_wwnr);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Daniel Bristot de Oliveira <bristot@kernel.org>");
+MODULE_DESCRIPTION("wwnr: wakeup while not running monitor");
diff --git a/kernel/trace/rv/monitors/wwnr/wwnr.h b/kernel/trace/rv/monitors/wwnr/wwnr.h
new file mode 100644
index 0000000000..d0d9c4b812
--- /dev/null
+++ b/kernel/trace/rv/monitors/wwnr/wwnr.h
@@ -0,0 +1,46 @@
+/*
+ * Automatically generated C representation of wwnr automaton
+ * For further information about this format, see kernel documentation:
+ * Documentation/trace/rv/deterministic_automata.rst
+ */
+
+enum states_wwnr {
+ not_running_wwnr = 0,
+ running_wwnr,
+ state_max_wwnr
+};
+
+#define INVALID_STATE state_max_wwnr
+
+enum events_wwnr {
+ switch_in_wwnr = 0,
+ switch_out_wwnr,
+ wakeup_wwnr,
+ event_max_wwnr
+};
+
+struct automaton_wwnr {
+ char *state_names[state_max_wwnr];
+ char *event_names[event_max_wwnr];
+ unsigned char function[state_max_wwnr][event_max_wwnr];
+ unsigned char initial_state;
+ bool final_states[state_max_wwnr];
+};
+
+static const struct automaton_wwnr automaton_wwnr = {
+ .state_names = {
+ "not_running",
+ "running"
+ },
+ .event_names = {
+ "switch_in",
+ "switch_out",
+ "wakeup"
+ },
+ .function = {
+ { running_wwnr, INVALID_STATE, not_running_wwnr },
+ { INVALID_STATE, not_running_wwnr, INVALID_STATE },
+ },
+ .initial_state = not_running_wwnr,
+ .final_states = { 1, 0 },
+};
diff --git a/kernel/trace/rv/reactor_panic.c b/kernel/trace/rv/reactor_panic.c
new file mode 100644
index 0000000000..0186ff4cbd
--- /dev/null
+++ b/kernel/trace/rv/reactor_panic.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * Panic RV reactor:
+ * Prints the exception msg to the kernel message log and panic().
+ */
+
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+
+static void rv_panic_reaction(char *msg)
+{
+ panic(msg);
+}
+
+static struct rv_reactor rv_panic = {
+ .name = "panic",
+ .description = "panic the system if an exception is found.",
+ .react = rv_panic_reaction
+};
+
+static int __init register_react_panic(void)
+{
+ rv_register_reactor(&rv_panic);
+ return 0;
+}
+
+static void __exit unregister_react_panic(void)
+{
+ rv_unregister_reactor(&rv_panic);
+}
+
+module_init(register_react_panic);
+module_exit(unregister_react_panic);
+
+MODULE_AUTHOR("Daniel Bristot de Oliveira");
+MODULE_DESCRIPTION("panic rv reactor: panic if an exception is found.");
diff --git a/kernel/trace/rv/reactor_printk.c b/kernel/trace/rv/reactor_printk.c
new file mode 100644
index 0000000000..178759dbf8
--- /dev/null
+++ b/kernel/trace/rv/reactor_printk.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * Printk RV reactor:
+ * Prints the exception msg to the kernel message log.
+ */
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+
+static void rv_printk_reaction(char *msg)
+{
+ printk_deferred(msg);
+}
+
+static struct rv_reactor rv_printk = {
+ .name = "printk",
+ .description = "prints the exception msg to the kernel message log.",
+ .react = rv_printk_reaction
+};
+
+static int __init register_react_printk(void)
+{
+ rv_register_reactor(&rv_printk);
+ return 0;
+}
+
+static void __exit unregister_react_printk(void)
+{
+ rv_unregister_reactor(&rv_printk);
+}
+
+module_init(register_react_printk);
+module_exit(unregister_react_printk);
+
+MODULE_AUTHOR("Daniel Bristot de Oliveira");
+MODULE_DESCRIPTION("printk rv reactor: printk if an exception is hit.");
diff --git a/kernel/trace/rv/rv.c b/kernel/trace/rv/rv.c
new file mode 100644
index 0000000000..2f68e93fff
--- /dev/null
+++ b/kernel/trace/rv/rv.c
@@ -0,0 +1,797 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * This is the online Runtime Verification (RV) interface.
+ *
+ * RV is a lightweight (yet rigorous) method that complements classical
+ * exhaustive verification techniques (such as model checking and
+ * theorem proving) with a more practical approach to complex systems.
+ *
+ * RV works by analyzing the trace of the system's actual execution,
+ * comparing it against a formal specification of the system behavior.
+ * RV can give precise information on the runtime behavior of the
+ * monitored system while enabling the reaction for unexpected
+ * events, avoiding, for example, the propagation of a failure on
+ * safety-critical systems.
+ *
+ * The development of this interface roots in the development of the
+ * paper:
+ *
+ * De Oliveira, Daniel Bristot; Cucinotta, Tommaso; De Oliveira, Romulo
+ * Silva. Efficient formal verification for the Linux kernel. In:
+ * International Conference on Software Engineering and Formal Methods.
+ * Springer, Cham, 2019. p. 315-332.
+ *
+ * And:
+ *
+ * De Oliveira, Daniel Bristot, et al. Automata-based formal analysis
+ * and verification of the real-time Linux kernel. PhD Thesis, 2020.
+ *
+ * == Runtime monitor interface ==
+ *
+ * A monitor is the central part of the runtime verification of a system.
+ *
+ * The monitor stands in between the formal specification of the desired
+ * (or undesired) behavior, and the trace of the actual system.
+ *
+ * In Linux terms, the runtime verification monitors are encapsulated
+ * inside the "RV monitor" abstraction. A RV monitor includes a reference
+ * model of the system, a set of instances of the monitor (per-cpu monitor,
+ * per-task monitor, and so on), and the helper functions that glue the
+ * monitor to the system via trace. Generally, a monitor includes some form
+ * of trace output as a reaction for event parsing and exceptions,
+ * as depicted bellow:
+ *
+ * Linux +----- RV Monitor ----------------------------------+ Formal
+ * Realm | | Realm
+ * +-------------------+ +----------------+ +-----------------+
+ * | Linux kernel | | Monitor | | Reference |
+ * | Tracing | -> | Instance(s) | <- | Model |
+ * | (instrumentation) | | (verification) | | (specification) |
+ * +-------------------+ +----------------+ +-----------------+
+ * | | |
+ * | V |
+ * | +----------+ |
+ * | | Reaction | |
+ * | +--+--+--+-+ |
+ * | | | | |
+ * | | | +-> trace output ? |
+ * +------------------------|--|----------------------+
+ * | +----> panic ?
+ * +-------> <user-specified>
+ *
+ * This file implements the interface for loading RV monitors, and
+ * to control the verification session.
+ *
+ * == Registering monitors ==
+ *
+ * The struct rv_monitor defines a set of callback functions to control
+ * a verification session. For instance, when a given monitor is enabled,
+ * the "enable" callback function is called to hook the instrumentation
+ * functions to the kernel trace events. The "disable" function is called
+ * when disabling the verification session.
+ *
+ * A RV monitor is registered via:
+ * int rv_register_monitor(struct rv_monitor *monitor);
+ * And unregistered via:
+ * int rv_unregister_monitor(struct rv_monitor *monitor);
+ *
+ * == User interface ==
+ *
+ * The user interface resembles kernel tracing interface. It presents
+ * these files:
+ *
+ * "available_monitors"
+ * - List the available monitors, one per line.
+ *
+ * For example:
+ * # cat available_monitors
+ * wip
+ * wwnr
+ *
+ * "enabled_monitors"
+ * - Lists the enabled monitors, one per line;
+ * - Writing to it enables a given monitor;
+ * - Writing a monitor name with a '!' prefix disables it;
+ * - Truncating the file disables all enabled monitors.
+ *
+ * For example:
+ * # cat enabled_monitors
+ * # echo wip > enabled_monitors
+ * # echo wwnr >> enabled_monitors
+ * # cat enabled_monitors
+ * wip
+ * wwnr
+ * # echo '!wip' >> enabled_monitors
+ * # cat enabled_monitors
+ * wwnr
+ * # echo > enabled_monitors
+ * # cat enabled_monitors
+ * #
+ *
+ * Note that more than one monitor can be enabled concurrently.
+ *
+ * "monitoring_on"
+ * - It is an on/off general switcher for monitoring. Note
+ * that it does not disable enabled monitors or detach events,
+ * but stops the per-entity monitors from monitoring the events
+ * received from the instrumentation. It resembles the "tracing_on"
+ * switcher.
+ *
+ * "monitors/"
+ * Each monitor will have its own directory inside "monitors/". There
+ * the monitor specific files will be presented.
+ * The "monitors/" directory resembles the "events" directory on
+ * tracefs.
+ *
+ * For example:
+ * # cd monitors/wip/
+ * # ls
+ * desc enable
+ * # cat desc
+ * auto-generated wakeup in preemptive monitor.
+ * # cat enable
+ * 0
+ *
+ * For further information, see:
+ * Documentation/trace/rv/runtime-verification.rst
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+
+#ifdef CONFIG_DA_MON_EVENTS
+#define CREATE_TRACE_POINTS
+#include <trace/events/rv.h>
+#endif
+
+#include "rv.h"
+
+DEFINE_MUTEX(rv_interface_lock);
+
+static struct rv_interface rv_root;
+
+struct dentry *get_monitors_root(void)
+{
+ return rv_root.monitors_dir;
+}
+
+/*
+ * Interface for the monitor register.
+ */
+static LIST_HEAD(rv_monitors_list);
+
+static int task_monitor_count;
+static bool task_monitor_slots[RV_PER_TASK_MONITORS];
+
+int rv_get_task_monitor_slot(void)
+{
+ int i;
+
+ lockdep_assert_held(&rv_interface_lock);
+
+ if (task_monitor_count == RV_PER_TASK_MONITORS)
+ return -EBUSY;
+
+ task_monitor_count++;
+
+ for (i = 0; i < RV_PER_TASK_MONITORS; i++) {
+ if (task_monitor_slots[i] == false) {
+ task_monitor_slots[i] = true;
+ return i;
+ }
+ }
+
+ WARN_ONCE(1, "RV task_monitor_count and slots are out of sync\n");
+
+ return -EINVAL;
+}
+
+void rv_put_task_monitor_slot(int slot)
+{
+ lockdep_assert_held(&rv_interface_lock);
+
+ if (slot < 0 || slot >= RV_PER_TASK_MONITORS) {
+ WARN_ONCE(1, "RV releasing an invalid slot!: %d\n", slot);
+ return;
+ }
+
+ WARN_ONCE(!task_monitor_slots[slot], "RV releasing unused task_monitor_slots: %d\n",
+ slot);
+
+ task_monitor_count--;
+ task_monitor_slots[slot] = false;
+}
+
+/*
+ * This section collects the monitor/ files and folders.
+ */
+static ssize_t monitor_enable_read_data(struct file *filp, char __user *user_buf, size_t count,
+ loff_t *ppos)
+{
+ struct rv_monitor_def *mdef = filp->private_data;
+ const char *buff;
+
+ buff = mdef->monitor->enabled ? "1\n" : "0\n";
+
+ return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
+}
+
+/*
+ * __rv_disable_monitor - disabled an enabled monitor
+ */
+static int __rv_disable_monitor(struct rv_monitor_def *mdef, bool sync)
+{
+ lockdep_assert_held(&rv_interface_lock);
+
+ if (mdef->monitor->enabled) {
+ mdef->monitor->enabled = 0;
+ mdef->monitor->disable();
+
+ /*
+ * Wait for the execution of all events to finish.
+ * Otherwise, the data used by the monitor could
+ * be inconsistent. i.e., if the monitor is re-enabled.
+ */
+ if (sync)
+ tracepoint_synchronize_unregister();
+ return 1;
+ }
+ return 0;
+}
+
+/**
+ * rv_disable_monitor - disable a given runtime monitor
+ *
+ * Returns 0 on success.
+ */
+int rv_disable_monitor(struct rv_monitor_def *mdef)
+{
+ __rv_disable_monitor(mdef, true);
+ return 0;
+}
+
+/**
+ * rv_enable_monitor - enable a given runtime monitor
+ *
+ * Returns 0 on success, error otherwise.
+ */
+int rv_enable_monitor(struct rv_monitor_def *mdef)
+{
+ int retval;
+
+ lockdep_assert_held(&rv_interface_lock);
+
+ if (mdef->monitor->enabled)
+ return 0;
+
+ retval = mdef->monitor->enable();
+
+ if (!retval)
+ mdef->monitor->enabled = 1;
+
+ return retval;
+}
+
+/*
+ * interface for enabling/disabling a monitor.
+ */
+static ssize_t monitor_enable_write_data(struct file *filp, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct rv_monitor_def *mdef = filp->private_data;
+ int retval;
+ bool val;
+
+ retval = kstrtobool_from_user(user_buf, count, &val);
+ if (retval)
+ return retval;
+
+ mutex_lock(&rv_interface_lock);
+
+ if (val)
+ retval = rv_enable_monitor(mdef);
+ else
+ retval = rv_disable_monitor(mdef);
+
+ mutex_unlock(&rv_interface_lock);
+
+ return retval ? : count;
+}
+
+static const struct file_operations interface_enable_fops = {
+ .open = simple_open,
+ .llseek = no_llseek,
+ .write = monitor_enable_write_data,
+ .read = monitor_enable_read_data,
+};
+
+/*
+ * Interface to read monitors description.
+ */
+static ssize_t monitor_desc_read_data(struct file *filp, char __user *user_buf, size_t count,
+ loff_t *ppos)
+{
+ struct rv_monitor_def *mdef = filp->private_data;
+ char buff[256];
+
+ memset(buff, 0, sizeof(buff));
+
+ snprintf(buff, sizeof(buff), "%s\n", mdef->monitor->description);
+
+ return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff) + 1);
+}
+
+static const struct file_operations interface_desc_fops = {
+ .open = simple_open,
+ .llseek = no_llseek,
+ .read = monitor_desc_read_data,
+};
+
+/*
+ * During the registration of a monitor, this function creates
+ * the monitor dir, where the specific options of the monitor
+ * are exposed.
+ */
+static int create_monitor_dir(struct rv_monitor_def *mdef)
+{
+ struct dentry *root = get_monitors_root();
+ const char *name = mdef->monitor->name;
+ struct dentry *tmp;
+ int retval;
+
+ mdef->root_d = rv_create_dir(name, root);
+ if (!mdef->root_d)
+ return -ENOMEM;
+
+ tmp = rv_create_file("enable", RV_MODE_WRITE, mdef->root_d, mdef, &interface_enable_fops);
+ if (!tmp) {
+ retval = -ENOMEM;
+ goto out_remove_root;
+ }
+
+ tmp = rv_create_file("desc", RV_MODE_READ, mdef->root_d, mdef, &interface_desc_fops);
+ if (!tmp) {
+ retval = -ENOMEM;
+ goto out_remove_root;
+ }
+
+ retval = reactor_populate_monitor(mdef);
+ if (retval)
+ goto out_remove_root;
+
+ return 0;
+
+out_remove_root:
+ rv_remove(mdef->root_d);
+ return retval;
+}
+
+/*
+ * Available/Enable monitor shared seq functions.
+ */
+static int monitors_show(struct seq_file *m, void *p)
+{
+ struct rv_monitor_def *mon_def = p;
+
+ seq_printf(m, "%s\n", mon_def->monitor->name);
+ return 0;
+}
+
+/*
+ * Used by the seq file operations at the end of a read
+ * operation.
+ */
+static void monitors_stop(struct seq_file *m, void *p)
+{
+ mutex_unlock(&rv_interface_lock);
+}
+
+/*
+ * Available monitor seq functions.
+ */
+static void *available_monitors_start(struct seq_file *m, loff_t *pos)
+{
+ mutex_lock(&rv_interface_lock);
+ return seq_list_start(&rv_monitors_list, *pos);
+}
+
+static void *available_monitors_next(struct seq_file *m, void *p, loff_t *pos)
+{
+ return seq_list_next(p, &rv_monitors_list, pos);
+}
+
+/*
+ * Enable monitor seq functions.
+ */
+static void *enabled_monitors_next(struct seq_file *m, void *p, loff_t *pos)
+{
+ struct rv_monitor_def *m_def = p;
+
+ (*pos)++;
+
+ list_for_each_entry_continue(m_def, &rv_monitors_list, list) {
+ if (m_def->monitor->enabled)
+ return m_def;
+ }
+
+ return NULL;
+}
+
+static void *enabled_monitors_start(struct seq_file *m, loff_t *pos)
+{
+ struct rv_monitor_def *m_def;
+ loff_t l;
+
+ mutex_lock(&rv_interface_lock);
+
+ if (list_empty(&rv_monitors_list))
+ return NULL;
+
+ m_def = list_entry(&rv_monitors_list, struct rv_monitor_def, list);
+
+ for (l = 0; l <= *pos; ) {
+ m_def = enabled_monitors_next(m, m_def, &l);
+ if (!m_def)
+ break;
+ }
+
+ return m_def;
+}
+
+/*
+ * available/enabled monitors seq definition.
+ */
+static const struct seq_operations available_monitors_seq_ops = {
+ .start = available_monitors_start,
+ .next = available_monitors_next,
+ .stop = monitors_stop,
+ .show = monitors_show
+};
+
+static const struct seq_operations enabled_monitors_seq_ops = {
+ .start = enabled_monitors_start,
+ .next = enabled_monitors_next,
+ .stop = monitors_stop,
+ .show = monitors_show
+};
+
+/*
+ * available_monitors interface.
+ */
+static int available_monitors_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &available_monitors_seq_ops);
+};
+
+static const struct file_operations available_monitors_ops = {
+ .open = available_monitors_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release
+};
+
+/*
+ * enabled_monitors interface.
+ */
+static void disable_all_monitors(void)
+{
+ struct rv_monitor_def *mdef;
+ int enabled = 0;
+
+ mutex_lock(&rv_interface_lock);
+
+ list_for_each_entry(mdef, &rv_monitors_list, list)
+ enabled += __rv_disable_monitor(mdef, false);
+
+ if (enabled) {
+ /*
+ * Wait for the execution of all events to finish.
+ * Otherwise, the data used by the monitor could
+ * be inconsistent. i.e., if the monitor is re-enabled.
+ */
+ tracepoint_synchronize_unregister();
+ }
+
+ mutex_unlock(&rv_interface_lock);
+}
+
+static int enabled_monitors_open(struct inode *inode, struct file *file)
+{
+ if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
+ disable_all_monitors();
+
+ return seq_open(file, &enabled_monitors_seq_ops);
+};
+
+static ssize_t enabled_monitors_write(struct file *filp, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char buff[MAX_RV_MONITOR_NAME_SIZE + 2];
+ struct rv_monitor_def *mdef;
+ int retval = -EINVAL;
+ bool enable = true;
+ char *ptr;
+ int len;
+
+ if (count < 1 || count > MAX_RV_MONITOR_NAME_SIZE + 1)
+ return -EINVAL;
+
+ memset(buff, 0, sizeof(buff));
+
+ retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf, count);
+ if (retval < 0)
+ return -EFAULT;
+
+ ptr = strim(buff);
+
+ if (ptr[0] == '!') {
+ enable = false;
+ ptr++;
+ }
+
+ len = strlen(ptr);
+ if (!len)
+ return count;
+
+ mutex_lock(&rv_interface_lock);
+
+ retval = -EINVAL;
+
+ list_for_each_entry(mdef, &rv_monitors_list, list) {
+ if (strcmp(ptr, mdef->monitor->name) != 0)
+ continue;
+
+ /*
+ * Monitor found!
+ */
+ if (enable)
+ retval = rv_enable_monitor(mdef);
+ else
+ retval = rv_disable_monitor(mdef);
+
+ if (!retval)
+ retval = count;
+
+ break;
+ }
+
+ mutex_unlock(&rv_interface_lock);
+ return retval;
+}
+
+static const struct file_operations enabled_monitors_ops = {
+ .open = enabled_monitors_open,
+ .read = seq_read,
+ .write = enabled_monitors_write,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+/*
+ * Monitoring on global switcher!
+ */
+static bool __read_mostly monitoring_on;
+
+/**
+ * rv_monitoring_on - checks if monitoring is on
+ *
+ * Returns 1 if on, 0 otherwise.
+ */
+bool rv_monitoring_on(void)
+{
+ /* Ensures that concurrent monitors read consistent monitoring_on */
+ smp_rmb();
+ return READ_ONCE(monitoring_on);
+}
+
+/*
+ * monitoring_on general switcher.
+ */
+static ssize_t monitoring_on_read_data(struct file *filp, char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ const char *buff;
+
+ buff = rv_monitoring_on() ? "1\n" : "0\n";
+
+ return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff) + 1);
+}
+
+static void turn_monitoring_off(void)
+{
+ WRITE_ONCE(monitoring_on, false);
+ /* Ensures that concurrent monitors read consistent monitoring_on */
+ smp_wmb();
+}
+
+static void reset_all_monitors(void)
+{
+ struct rv_monitor_def *mdef;
+
+ list_for_each_entry(mdef, &rv_monitors_list, list) {
+ if (mdef->monitor->enabled)
+ mdef->monitor->reset();
+ }
+}
+
+static void turn_monitoring_on(void)
+{
+ WRITE_ONCE(monitoring_on, true);
+ /* Ensures that concurrent monitors read consistent monitoring_on */
+ smp_wmb();
+}
+
+static void turn_monitoring_on_with_reset(void)
+{
+ lockdep_assert_held(&rv_interface_lock);
+
+ if (rv_monitoring_on())
+ return;
+
+ /*
+ * Monitors might be out of sync with the system if events were not
+ * processed because of !rv_monitoring_on().
+ *
+ * Reset all monitors, forcing a re-sync.
+ */
+ reset_all_monitors();
+ turn_monitoring_on();
+}
+
+static ssize_t monitoring_on_write_data(struct file *filp, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ int retval;
+ bool val;
+
+ retval = kstrtobool_from_user(user_buf, count, &val);
+ if (retval)
+ return retval;
+
+ mutex_lock(&rv_interface_lock);
+
+ if (val)
+ turn_monitoring_on_with_reset();
+ else
+ turn_monitoring_off();
+
+ /*
+ * Wait for the execution of all events to finish
+ * before returning to user-space.
+ */
+ tracepoint_synchronize_unregister();
+
+ mutex_unlock(&rv_interface_lock);
+
+ return count;
+}
+
+static const struct file_operations monitoring_on_fops = {
+ .open = simple_open,
+ .llseek = no_llseek,
+ .write = monitoring_on_write_data,
+ .read = monitoring_on_read_data,
+};
+
+static void destroy_monitor_dir(struct rv_monitor_def *mdef)
+{
+ reactor_cleanup_monitor(mdef);
+ rv_remove(mdef->root_d);
+}
+
+/**
+ * rv_register_monitor - register a rv monitor.
+ * @monitor: The rv_monitor to be registered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_register_monitor(struct rv_monitor *monitor)
+{
+ struct rv_monitor_def *r;
+ int retval = 0;
+
+ if (strlen(monitor->name) >= MAX_RV_MONITOR_NAME_SIZE) {
+ pr_info("Monitor %s has a name longer than %d\n", monitor->name,
+ MAX_RV_MONITOR_NAME_SIZE);
+ return -1;
+ }
+
+ mutex_lock(&rv_interface_lock);
+
+ list_for_each_entry(r, &rv_monitors_list, list) {
+ if (strcmp(monitor->name, r->monitor->name) == 0) {
+ pr_info("Monitor %s is already registered\n", monitor->name);
+ retval = -1;
+ goto out_unlock;
+ }
+ }
+
+ r = kzalloc(sizeof(struct rv_monitor_def), GFP_KERNEL);
+ if (!r) {
+ retval = -ENOMEM;
+ goto out_unlock;
+ }
+
+ r->monitor = monitor;
+
+ retval = create_monitor_dir(r);
+ if (retval) {
+ kfree(r);
+ goto out_unlock;
+ }
+
+ list_add_tail(&r->list, &rv_monitors_list);
+
+out_unlock:
+ mutex_unlock(&rv_interface_lock);
+ return retval;
+}
+
+/**
+ * rv_unregister_monitor - unregister a rv monitor.
+ * @monitor: The rv_monitor to be unregistered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_unregister_monitor(struct rv_monitor *monitor)
+{
+ struct rv_monitor_def *ptr, *next;
+
+ mutex_lock(&rv_interface_lock);
+
+ list_for_each_entry_safe(ptr, next, &rv_monitors_list, list) {
+ if (strcmp(monitor->name, ptr->monitor->name) == 0) {
+ rv_disable_monitor(ptr);
+ list_del(&ptr->list);
+ destroy_monitor_dir(ptr);
+ }
+ }
+
+ mutex_unlock(&rv_interface_lock);
+ return 0;
+}
+
+int __init rv_init_interface(void)
+{
+ struct dentry *tmp;
+ int retval;
+
+ rv_root.root_dir = rv_create_dir("rv", NULL);
+ if (!rv_root.root_dir)
+ goto out_err;
+
+ rv_root.monitors_dir = rv_create_dir("monitors", rv_root.root_dir);
+ if (!rv_root.monitors_dir)
+ goto out_err;
+
+ tmp = rv_create_file("available_monitors", RV_MODE_READ, rv_root.root_dir, NULL,
+ &available_monitors_ops);
+ if (!tmp)
+ goto out_err;
+
+ tmp = rv_create_file("enabled_monitors", RV_MODE_WRITE, rv_root.root_dir, NULL,
+ &enabled_monitors_ops);
+ if (!tmp)
+ goto out_err;
+
+ tmp = rv_create_file("monitoring_on", RV_MODE_WRITE, rv_root.root_dir, NULL,
+ &monitoring_on_fops);
+ if (!tmp)
+ goto out_err;
+ retval = init_rv_reactors(rv_root.root_dir);
+ if (retval)
+ goto out_err;
+
+ turn_monitoring_on();
+
+ return 0;
+
+out_err:
+ rv_remove(rv_root.root_dir);
+ printk(KERN_ERR "RV: Error while creating the RV interface\n");
+ return 1;
+}
diff --git a/kernel/trace/rv/rv.h b/kernel/trace/rv/rv.h
new file mode 100644
index 0000000000..db6cb0913d
--- /dev/null
+++ b/kernel/trace/rv/rv.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/mutex.h>
+
+struct rv_interface {
+ struct dentry *root_dir;
+ struct dentry *monitors_dir;
+};
+
+#include "../trace.h"
+#include <linux/tracefs.h>
+#include <linux/rv.h>
+
+#define RV_MODE_WRITE TRACE_MODE_WRITE
+#define RV_MODE_READ TRACE_MODE_READ
+
+#define rv_create_dir tracefs_create_dir
+#define rv_create_file tracefs_create_file
+#define rv_remove tracefs_remove
+
+#define MAX_RV_MONITOR_NAME_SIZE 32
+#define MAX_RV_REACTOR_NAME_SIZE 32
+
+extern struct mutex rv_interface_lock;
+
+#ifdef CONFIG_RV_REACTORS
+struct rv_reactor_def {
+ struct list_head list;
+ struct rv_reactor *reactor;
+ /* protected by the monitor interface lock */
+ int counter;
+};
+#endif
+
+struct rv_monitor_def {
+ struct list_head list;
+ struct rv_monitor *monitor;
+ struct dentry *root_d;
+#ifdef CONFIG_RV_REACTORS
+ struct rv_reactor_def *rdef;
+ bool reacting;
+#endif
+ bool task_monitor;
+};
+
+struct dentry *get_monitors_root(void);
+int rv_disable_monitor(struct rv_monitor_def *mdef);
+int rv_enable_monitor(struct rv_monitor_def *mdef);
+
+#ifdef CONFIG_RV_REACTORS
+int reactor_populate_monitor(struct rv_monitor_def *mdef);
+void reactor_cleanup_monitor(struct rv_monitor_def *mdef);
+int init_rv_reactors(struct dentry *root_dir);
+#else
+static inline int reactor_populate_monitor(struct rv_monitor_def *mdef)
+{
+ return 0;
+}
+
+static inline void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
+{
+ return;
+}
+
+static inline int init_rv_reactors(struct dentry *root_dir)
+{
+ return 0;
+}
+#endif
diff --git a/kernel/trace/rv/rv_reactors.c b/kernel/trace/rv/rv_reactors.c
new file mode 100644
index 0000000000..6aae106695
--- /dev/null
+++ b/kernel/trace/rv/rv_reactors.c
@@ -0,0 +1,510 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * Runtime reactor interface.
+ *
+ * A runtime monitor can cause a reaction to the detection of an
+ * exception on the model's execution. By default, the monitors have
+ * tracing reactions, printing the monitor output via tracepoints.
+ * But other reactions can be added (on-demand) via this interface.
+ *
+ * == Registering reactors ==
+ *
+ * The struct rv_reactor defines a callback function to be executed
+ * in case of a model exception happens. The callback function
+ * receives a message to be (optionally) printed before executing
+ * the reaction.
+ *
+ * A RV reactor is registered via:
+ * int rv_register_reactor(struct rv_reactor *reactor)
+ * And unregistered via:
+ * int rv_unregister_reactor(struct rv_reactor *reactor)
+ *
+ * These functions are exported to modules, enabling reactors to be
+ * dynamically loaded.
+ *
+ * == User interface ==
+ *
+ * The user interface resembles the kernel tracing interface and
+ * presents these files:
+ *
+ * "available_reactors"
+ * - List the available reactors, one per line.
+ *
+ * For example:
+ * # cat available_reactors
+ * nop
+ * panic
+ * printk
+ *
+ * "reacting_on"
+ * - It is an on/off general switch for reactors, disabling
+ * all reactions.
+ *
+ * "monitors/MONITOR/reactors"
+ * - List available reactors, with the select reaction for the given
+ * MONITOR inside []. The default one is the nop (no operation)
+ * reactor.
+ * - Writing the name of an reactor enables it to the given
+ * MONITOR.
+ *
+ * For example:
+ * # cat monitors/wip/reactors
+ * [nop]
+ * panic
+ * printk
+ * # echo panic > monitors/wip/reactors
+ * # cat monitors/wip/reactors
+ * nop
+ * [panic]
+ * printk
+ */
+
+#include <linux/slab.h>
+
+#include "rv.h"
+
+/*
+ * Interface for the reactor register.
+ */
+static LIST_HEAD(rv_reactors_list);
+
+static struct rv_reactor_def *get_reactor_rdef_by_name(char *name)
+{
+ struct rv_reactor_def *r;
+
+ list_for_each_entry(r, &rv_reactors_list, list) {
+ if (strcmp(name, r->reactor->name) == 0)
+ return r;
+ }
+ return NULL;
+}
+
+/*
+ * Available reactors seq functions.
+ */
+static int reactors_show(struct seq_file *m, void *p)
+{
+ struct rv_reactor_def *rea_def = p;
+
+ seq_printf(m, "%s\n", rea_def->reactor->name);
+ return 0;
+}
+
+static void reactors_stop(struct seq_file *m, void *p)
+{
+ mutex_unlock(&rv_interface_lock);
+}
+
+static void *reactors_start(struct seq_file *m, loff_t *pos)
+{
+ mutex_lock(&rv_interface_lock);
+ return seq_list_start(&rv_reactors_list, *pos);
+}
+
+static void *reactors_next(struct seq_file *m, void *p, loff_t *pos)
+{
+ return seq_list_next(p, &rv_reactors_list, pos);
+}
+
+/*
+ * available_reactors seq definition.
+ */
+static const struct seq_operations available_reactors_seq_ops = {
+ .start = reactors_start,
+ .next = reactors_next,
+ .stop = reactors_stop,
+ .show = reactors_show
+};
+
+/*
+ * available_reactors interface.
+ */
+static int available_reactors_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &available_reactors_seq_ops);
+};
+
+static const struct file_operations available_reactors_ops = {
+ .open = available_reactors_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release
+};
+
+/*
+ * Monitor's reactor file.
+ */
+static int monitor_reactor_show(struct seq_file *m, void *p)
+{
+ struct rv_monitor_def *mdef = m->private;
+ struct rv_reactor_def *rdef = p;
+
+ if (mdef->rdef == rdef)
+ seq_printf(m, "[%s]\n", rdef->reactor->name);
+ else
+ seq_printf(m, "%s\n", rdef->reactor->name);
+ return 0;
+}
+
+/*
+ * available_reactors seq definition.
+ */
+static const struct seq_operations monitor_reactors_seq_ops = {
+ .start = reactors_start,
+ .next = reactors_next,
+ .stop = reactors_stop,
+ .show = monitor_reactor_show
+};
+
+static void monitor_swap_reactors(struct rv_monitor_def *mdef, struct rv_reactor_def *rdef,
+ bool reacting)
+{
+ bool monitor_enabled;
+
+ /* nothing to do */
+ if (mdef->rdef == rdef)
+ return;
+
+ monitor_enabled = mdef->monitor->enabled;
+ if (monitor_enabled)
+ rv_disable_monitor(mdef);
+
+ /* swap reactor's usage */
+ mdef->rdef->counter--;
+ rdef->counter++;
+
+ mdef->rdef = rdef;
+ mdef->reacting = reacting;
+ mdef->monitor->react = rdef->reactor->react;
+
+ if (monitor_enabled)
+ rv_enable_monitor(mdef);
+}
+
+static ssize_t
+monitor_reactors_write(struct file *file, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char buff[MAX_RV_REACTOR_NAME_SIZE + 2];
+ struct rv_monitor_def *mdef;
+ struct rv_reactor_def *rdef;
+ struct seq_file *seq_f;
+ int retval = -EINVAL;
+ bool enable;
+ char *ptr;
+ int len;
+
+ if (count < 1 || count > MAX_RV_REACTOR_NAME_SIZE + 1)
+ return -EINVAL;
+
+ memset(buff, 0, sizeof(buff));
+
+ retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf, count);
+ if (retval < 0)
+ return -EFAULT;
+
+ ptr = strim(buff);
+
+ len = strlen(ptr);
+ if (!len)
+ return count;
+
+ /*
+ * See monitor_reactors_open()
+ */
+ seq_f = file->private_data;
+ mdef = seq_f->private;
+
+ mutex_lock(&rv_interface_lock);
+
+ retval = -EINVAL;
+
+ list_for_each_entry(rdef, &rv_reactors_list, list) {
+ if (strcmp(ptr, rdef->reactor->name) != 0)
+ continue;
+
+ if (rdef == get_reactor_rdef_by_name("nop"))
+ enable = false;
+ else
+ enable = true;
+
+ monitor_swap_reactors(mdef, rdef, enable);
+
+ retval = count;
+ break;
+ }
+
+ mutex_unlock(&rv_interface_lock);
+
+ return retval;
+}
+
+/*
+ * available_reactors interface.
+ */
+static int monitor_reactors_open(struct inode *inode, struct file *file)
+{
+ struct rv_monitor_def *mdef = inode->i_private;
+ struct seq_file *seq_f;
+ int ret;
+
+ ret = seq_open(file, &monitor_reactors_seq_ops);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * seq_open stores the seq_file on the file->private data.
+ */
+ seq_f = file->private_data;
+
+ /*
+ * Copy the create file "private" data to the seq_file private data.
+ */
+ seq_f->private = mdef;
+
+ return 0;
+};
+
+static const struct file_operations monitor_reactors_ops = {
+ .open = monitor_reactors_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+ .write = monitor_reactors_write
+};
+
+static int __rv_register_reactor(struct rv_reactor *reactor)
+{
+ struct rv_reactor_def *r;
+
+ list_for_each_entry(r, &rv_reactors_list, list) {
+ if (strcmp(reactor->name, r->reactor->name) == 0) {
+ pr_info("Reactor %s is already registered\n", reactor->name);
+ return -EINVAL;
+ }
+ }
+
+ r = kzalloc(sizeof(struct rv_reactor_def), GFP_KERNEL);
+ if (!r)
+ return -ENOMEM;
+
+ r->reactor = reactor;
+ r->counter = 0;
+
+ list_add_tail(&r->list, &rv_reactors_list);
+
+ return 0;
+}
+
+/**
+ * rv_register_reactor - register a rv reactor.
+ * @reactor: The rv_reactor to be registered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_register_reactor(struct rv_reactor *reactor)
+{
+ int retval = 0;
+
+ if (strlen(reactor->name) >= MAX_RV_REACTOR_NAME_SIZE) {
+ pr_info("Reactor %s has a name longer than %d\n",
+ reactor->name, MAX_RV_MONITOR_NAME_SIZE);
+ return -EINVAL;
+ }
+
+ mutex_lock(&rv_interface_lock);
+ retval = __rv_register_reactor(reactor);
+ mutex_unlock(&rv_interface_lock);
+ return retval;
+}
+
+/**
+ * rv_unregister_reactor - unregister a rv reactor.
+ * @reactor: The rv_reactor to be unregistered.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int rv_unregister_reactor(struct rv_reactor *reactor)
+{
+ struct rv_reactor_def *ptr, *next;
+ int ret = 0;
+
+ mutex_lock(&rv_interface_lock);
+
+ list_for_each_entry_safe(ptr, next, &rv_reactors_list, list) {
+ if (strcmp(reactor->name, ptr->reactor->name) == 0) {
+
+ if (!ptr->counter) {
+ list_del(&ptr->list);
+ } else {
+ printk(KERN_WARNING
+ "rv: the rv_reactor %s is in use by %d monitor(s)\n",
+ ptr->reactor->name, ptr->counter);
+ printk(KERN_WARNING "rv: the rv_reactor %s cannot be removed\n",
+ ptr->reactor->name);
+ ret = -EBUSY;
+ break;
+ }
+ }
+ }
+
+ mutex_unlock(&rv_interface_lock);
+ return ret;
+}
+
+/*
+ * reacting_on interface.
+ */
+static bool __read_mostly reacting_on;
+
+/**
+ * rv_reacting_on - checks if reacting is on
+ *
+ * Returns 1 if on, 0 otherwise.
+ */
+bool rv_reacting_on(void)
+{
+ /* Ensures that concurrent monitors read consistent reacting_on */
+ smp_rmb();
+ return READ_ONCE(reacting_on);
+}
+
+static ssize_t reacting_on_read_data(struct file *filp,
+ char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ char *buff;
+
+ buff = rv_reacting_on() ? "1\n" : "0\n";
+
+ return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
+}
+
+static void turn_reacting_off(void)
+{
+ WRITE_ONCE(reacting_on, false);
+ /* Ensures that concurrent monitors read consistent reacting_on */
+ smp_wmb();
+}
+
+static void turn_reacting_on(void)
+{
+ WRITE_ONCE(reacting_on, true);
+ /* Ensures that concurrent monitors read consistent reacting_on */
+ smp_wmb();
+}
+
+static ssize_t reacting_on_write_data(struct file *filp, const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ int retval;
+ bool val;
+
+ retval = kstrtobool_from_user(user_buf, count, &val);
+ if (retval)
+ return retval;
+
+ mutex_lock(&rv_interface_lock);
+
+ if (val)
+ turn_reacting_on();
+ else
+ turn_reacting_off();
+
+ /*
+ * Wait for the execution of all events to finish
+ * before returning to user-space.
+ */
+ tracepoint_synchronize_unregister();
+
+ mutex_unlock(&rv_interface_lock);
+
+ return count;
+}
+
+static const struct file_operations reacting_on_fops = {
+ .open = simple_open,
+ .llseek = no_llseek,
+ .write = reacting_on_write_data,
+ .read = reacting_on_read_data,
+};
+
+/**
+ * reactor_populate_monitor - creates per monitor reactors file
+ * @mdef: monitor's definition.
+ *
+ * Returns 0 if successful, error otherwise.
+ */
+int reactor_populate_monitor(struct rv_monitor_def *mdef)
+{
+ struct dentry *tmp;
+
+ tmp = rv_create_file("reactors", RV_MODE_WRITE, mdef->root_d, mdef, &monitor_reactors_ops);
+ if (!tmp)
+ return -ENOMEM;
+
+ /*
+ * Configure as the rv_nop reactor.
+ */
+ mdef->rdef = get_reactor_rdef_by_name("nop");
+ mdef->rdef->counter++;
+ mdef->reacting = false;
+
+ return 0;
+}
+
+/**
+ * reactor_cleanup_monitor - cleanup a monitor reference
+ * @mdef: monitor's definition.
+ */
+void reactor_cleanup_monitor(struct rv_monitor_def *mdef)
+{
+ lockdep_assert_held(&rv_interface_lock);
+ mdef->rdef->counter--;
+ WARN_ON_ONCE(mdef->rdef->counter < 0);
+}
+
+/*
+ * Nop reactor register
+ */
+static void rv_nop_reaction(char *msg)
+{
+}
+
+static struct rv_reactor rv_nop = {
+ .name = "nop",
+ .description = "no-operation reactor: do nothing.",
+ .react = rv_nop_reaction
+};
+
+int init_rv_reactors(struct dentry *root_dir)
+{
+ struct dentry *available, *reacting;
+ int retval;
+
+ available = rv_create_file("available_reactors", RV_MODE_READ, root_dir, NULL,
+ &available_reactors_ops);
+ if (!available)
+ goto out_err;
+
+ reacting = rv_create_file("reacting_on", RV_MODE_WRITE, root_dir, NULL, &reacting_on_fops);
+ if (!reacting)
+ goto rm_available;
+
+ retval = __rv_register_reactor(&rv_nop);
+ if (retval)
+ goto rm_reacting;
+
+ turn_reacting_on();
+
+ return 0;
+
+rm_reacting:
+ rv_remove(reacting);
+rm_available:
+ rv_remove(available);
+out_err:
+ return -ENOMEM;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-18 21:42:38 +0000