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authorDaniel Bristot de Oliveira <bristot@kernel.org>2022-07-29 11:38:43 +0200
committerSteven Rostedt (Google) <rostedt@goodmis.org>2022-07-30 14:01:28 -0400
commit792575348ff70e05c6040d02fce38e949ef92c37 (patch)
tree253285c43e4c648ba170015817e2a02a34f5926f /include/rv
parent09ecd8b8c585c95a3b8dbdec86c15a981fdfeba1 (diff)
downloadlinux-792575348ff70e05c6040d02fce38e949ef92c37.tar.bz2
rv/include: Add deterministic automata monitor definition via C macros
In Linux terms, the runtime verification monitors are encapsulated inside the "RV monitor" abstraction. The "RV monitor" includes a set of instances of the monitor (per-cpu monitor, per-task monitor, and so on), the helper functions that glue the monitor to the system reference model, and the trace output as a reaction for event parsing and exceptions, as depicted below: Linux +----- RV Monitor ----------------------------------+ Formal Realm | | Realm +-------------------+ +----------------+ +-----------------+ | Linux kernel | | Monitor | | Reference | | Tracing | -> | Instance(s) | <- | Model | | (instrumentation) | | (verification) | | (specification) | +-------------------+ +----------------+ +-----------------+ | | | | V | | +----------+ | | | Reaction | | | +--+--+--+-+ | | | | | | | | | +-> trace output ? | +------------------------|--|----------------------+ | +----> panic ? +-------> <user-specified> Add the rv/da_monitor.h, enabling automatic code generation for the *Monitor Instance(s)* using C macros, and code to support it. The benefits of the usage of macro for monitor synthesis are 3-fold as it: - Reduces the code duplication; - Facilitates the bug fix/improvement; - Avoids the case of developers changing the core of the monitor code to manipulate the model in a (let's say) non-standard way. This initial implementation presents three different types of monitor instances: - DECLARE_DA_MON_GLOBAL(name, type) - DECLARE_DA_MON_PER_CPU(name, type) - DECLARE_DA_MON_PER_TASK(name, type) The first declares the functions for a global deterministic automata monitor, the second for monitors with per-cpu instances, and the third with per-task instances. Link: https://lkml.kernel.org/r/51b0bf425a281e226dfeba7401d2115d6091f84e.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck <wim@linux-watchdog.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Gabriele Paoloni <gpaoloni@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: Tao Zhou <tao.zhou@linux.dev> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'include/rv')
-rw-r--r--include/rv/da_monitor.h541
1 files changed, 541 insertions, 0 deletions
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
new file mode 100644
index 000000000000..001bc298289f
--- /dev/null
+++ b/include/rv/da_monitor.h
@@ -0,0 +1,541 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
+ *
+ * Deterministic automata (DA) monitor functions, to be used together
+ * with automata models in C generated by the dot2k tool.
+ *
+ * The dot2k tool is available at tools/verification/dot2k/
+ */
+
+#include <rv/automata.h>
+#include <linux/rv.h>
+#include <linux/bug.h>
+
+#ifdef CONFIG_RV_REACTORS
+
+#define DECLARE_RV_REACTING_HELPERS(name, type) \
+static char REACT_MSG_##name[1024]; \
+ \
+static inline char *format_react_msg_##name(type curr_state, type event) \
+{ \
+ snprintf(REACT_MSG_##name, 1024, \
+ "rv: monitor %s does not allow event %s on state %s\n", \
+ #name, \
+ model_get_event_name_##name(event), \
+ model_get_state_name_##name(curr_state)); \
+ return REACT_MSG_##name; \
+} \
+ \
+static void cond_react_##name(char *msg) \
+{ \
+ if (rv_##name.react) \
+ rv_##name.react(msg); \
+} \
+ \
+static bool rv_reacting_on_##name(void) \
+{ \
+ return rv_reacting_on(); \
+}
+
+#else /* CONFIG_RV_REACTOR */
+
+#define DECLARE_RV_REACTING_HELPERS(name, type) \
+static inline char *format_react_msg_##name(type curr_state, type event) \
+{ \
+ return NULL; \
+} \
+ \
+static void cond_react_##name(char *msg) \
+{ \
+ return; \
+} \
+ \
+static bool rv_reacting_on_##name(void) \
+{ \
+ return 0; \
+}
+#endif
+
+/*
+ * Generic helpers for all types of deterministic automata monitors.
+ */
+#define DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
+ \
+DECLARE_RV_REACTING_HELPERS(name, type) \
+ \
+/* \
+ * da_monitor_reset_##name - reset a monitor and setting it to init state \
+ */ \
+static inline void da_monitor_reset_##name(struct da_monitor *da_mon) \
+{ \
+ da_mon->monitoring = 0; \
+ da_mon->curr_state = model_get_initial_state_##name(); \
+} \
+ \
+/* \
+ * da_monitor_curr_state_##name - return the current state \
+ */ \
+static inline type da_monitor_curr_state_##name(struct da_monitor *da_mon) \
+{ \
+ return da_mon->curr_state; \
+} \
+ \
+/* \
+ * da_monitor_set_state_##name - set the new current state \
+ */ \
+static inline void \
+da_monitor_set_state_##name(struct da_monitor *da_mon, enum states_##name state) \
+{ \
+ da_mon->curr_state = state; \
+} \
+ \
+/* \
+ * da_monitor_start_##name - start monitoring \
+ * \
+ * The monitor will ignore all events until monitoring is set to true. This \
+ * function needs to be called to tell the monitor to start monitoring. \
+ */ \
+static inline void da_monitor_start_##name(struct da_monitor *da_mon) \
+{ \
+ da_mon->curr_state = model_get_initial_state_##name(); \
+ da_mon->monitoring = 1; \
+} \
+ \
+/* \
+ * da_monitoring_##name - returns true if the monitor is processing events \
+ */ \
+static inline bool da_monitoring_##name(struct da_monitor *da_mon) \
+{ \
+ return da_mon->monitoring; \
+} \
+ \
+/* \
+ * da_monitor_enabled_##name - checks if the monitor is enabled \
+ */ \
+static inline bool da_monitor_enabled_##name(void) \
+{ \
+ /* global switch */ \
+ if (unlikely(!rv_monitoring_on())) \
+ return 0; \
+ \
+ /* monitor enabled */ \
+ if (unlikely(!rv_##name.enabled)) \
+ return 0; \
+ \
+ return 1; \
+} \
+ \
+/* \
+ * da_monitor_handling_event_##name - checks if the monitor is ready to handle events \
+ */ \
+static inline bool da_monitor_handling_event_##name(struct da_monitor *da_mon) \
+{ \
+ \
+ if (!da_monitor_enabled_##name()) \
+ return 0; \
+ \
+ /* monitor is actually monitoring */ \
+ if (unlikely(!da_monitoring_##name(da_mon))) \
+ return 0; \
+ \
+ return 1; \
+}
+
+/*
+ * Event handler for implicit monitors. Implicit monitor is the one which the
+ * handler does not need to specify which da_monitor to manipulate. Examples
+ * of implicit monitor are the per_cpu or the global ones.
+ */
+#define DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
+ \
+static inline bool \
+da_event_##name(struct da_monitor *da_mon, enum events_##name event) \
+{ \
+ type curr_state = da_monitor_curr_state_##name(da_mon); \
+ type next_state = model_get_next_state_##name(curr_state, event); \
+ \
+ if (next_state != INVALID_STATE) { \
+ da_monitor_set_state_##name(da_mon, next_state); \
+ \
+ trace_event_##name(model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event), \
+ model_get_state_name_##name(next_state), \
+ model_is_final_state_##name(next_state)); \
+ \
+ return true; \
+ } \
+ \
+ if (rv_reacting_on_##name()) \
+ cond_react_##name(format_react_msg_##name(curr_state, event)); \
+ \
+ trace_error_##name(model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event)); \
+ \
+ return false; \
+} \
+
+/*
+ * Event handler for per_task monitors.
+ */
+#define DECLARE_DA_MON_MODEL_HANDLER_PER_TASK(name, type) \
+ \
+static inline bool da_event_##name(struct da_monitor *da_mon, struct task_struct *tsk, \
+ enum events_##name event) \
+{ \
+ type curr_state = da_monitor_curr_state_##name(da_mon); \
+ type next_state = model_get_next_state_##name(curr_state, event); \
+ \
+ if (next_state != INVALID_STATE) { \
+ da_monitor_set_state_##name(da_mon, next_state); \
+ \
+ trace_event_##name(tsk->pid, \
+ model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event), \
+ model_get_state_name_##name(next_state), \
+ model_is_final_state_##name(next_state)); \
+ \
+ return true; \
+ } \
+ \
+ if (rv_reacting_on_##name()) \
+ cond_react_##name(format_react_msg_##name(curr_state, event)); \
+ \
+ trace_error_##name(tsk->pid, \
+ model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event)); \
+ \
+ return false; \
+}
+
+/*
+ * Functions to define, init and get a global monitor.
+ */
+#define DECLARE_DA_MON_INIT_GLOBAL(name, type) \
+ \
+/* \
+ * global monitor (a single variable) \
+ */ \
+static struct da_monitor da_mon_##name; \
+ \
+/* \
+ * da_get_monitor_##name - return the global monitor address \
+ */ \
+static struct da_monitor *da_get_monitor_##name(void) \
+{ \
+ return &da_mon_##name; \
+} \
+ \
+/* \
+ * da_monitor_reset_all_##name - reset the single monitor \
+ */ \
+static void da_monitor_reset_all_##name(void) \
+{ \
+ da_monitor_reset_##name(da_get_monitor_##name()); \
+} \
+ \
+/* \
+ * da_monitor_init_##name - initialize a monitor \
+ */ \
+static inline int da_monitor_init_##name(void) \
+{ \
+ da_monitor_reset_all_##name(); \
+ return 0; \
+} \
+ \
+/* \
+ * da_monitor_destroy_##name - destroy the monitor \
+ */ \
+static inline void da_monitor_destroy_##name(void) \
+{ \
+ return; \
+}
+
+/*
+ * Functions to define, init and get a per-cpu monitor.
+ */
+#define DECLARE_DA_MON_INIT_PER_CPU(name, type) \
+ \
+/* \
+ * per-cpu monitor variables \
+ */ \
+DEFINE_PER_CPU(struct da_monitor, da_mon_##name); \
+ \
+/* \
+ * da_get_monitor_##name - return current CPU monitor address \
+ */ \
+static struct da_monitor *da_get_monitor_##name(void) \
+{ \
+ return this_cpu_ptr(&da_mon_##name); \
+} \
+ \
+/* \
+ * da_monitor_reset_all_##name - reset all CPUs' monitor \
+ */ \
+static void da_monitor_reset_all_##name(void) \
+{ \
+ struct da_monitor *da_mon; \
+ int cpu; \
+ for_each_cpu(cpu, cpu_online_mask) { \
+ da_mon = per_cpu_ptr(&da_mon_##name, cpu); \
+ da_monitor_reset_##name(da_mon); \
+ } \
+} \
+ \
+/* \
+ * da_monitor_init_##name - initialize all CPUs' monitor \
+ */ \
+static inline int da_monitor_init_##name(void) \
+{ \
+ da_monitor_reset_all_##name(); \
+ return 0; \
+} \
+ \
+/* \
+ * da_monitor_destroy_##name - destroy the monitor \
+ */ \
+static inline void da_monitor_destroy_##name(void) \
+{ \
+ return; \
+}
+
+/*
+ * Functions to define, init and get a per-task monitor.
+ */
+#define DECLARE_DA_MON_INIT_PER_TASK(name, type) \
+ \
+/* \
+ * The per-task monitor is stored a vector in the task struct. This variable \
+ * stores the position on the vector reserved for this monitor. \
+ */ \
+static int task_mon_slot_##name = RV_PER_TASK_MONITOR_INIT; \
+ \
+/* \
+ * da_get_monitor_##name - return the monitor in the allocated slot for tsk \
+ */ \
+static inline struct da_monitor *da_get_monitor_##name(struct task_struct *tsk) \
+{ \
+ return &tsk->rv[task_mon_slot_##name].da_mon; \
+} \
+ \
+static void da_monitor_reset_all_##name(void) \
+{ \
+ struct task_struct *g, *p; \
+ \
+ read_lock(&tasklist_lock); \
+ for_each_process_thread(g, p) \
+ da_monitor_reset_##name(da_get_monitor_##name(p)); \
+ read_unlock(&tasklist_lock); \
+} \
+ \
+/* \
+ * da_monitor_init_##name - initialize the per-task monitor \
+ * \
+ * Try to allocate a slot in the task's vector of monitors. If there \
+ * is an available slot, use it and reset all task's monitor. \
+ */ \
+static int da_monitor_init_##name(void) \
+{ \
+ int slot; \
+ \
+ slot = rv_get_task_monitor_slot(); \
+ if (slot < 0 || slot >= RV_PER_TASK_MONITOR_INIT) \
+ return slot; \
+ \
+ task_mon_slot_##name = slot; \
+ \
+ da_monitor_reset_all_##name(); \
+ return 0; \
+} \
+ \
+/* \
+ * da_monitor_destroy_##name - return the allocated slot \
+ */ \
+static inline void da_monitor_destroy_##name(void) \
+{ \
+ if (task_mon_slot_##name == RV_PER_TASK_MONITOR_INIT) { \
+ WARN_ONCE(1, "Disabling a disabled monitor: " #name); \
+ return; \
+ } \
+ rv_put_task_monitor_slot(task_mon_slot_##name); \
+ task_mon_slot_##name = RV_PER_TASK_MONITOR_INIT; \
+ return; \
+}
+
+/*
+ * Handle event for implicit monitor: da_get_monitor_##name() will figure out
+ * the monitor.
+ */
+#define DECLARE_DA_MON_MONITOR_HANDLER_IMPLICIT(name, type) \
+ \
+static inline void __da_handle_event_##name(struct da_monitor *da_mon, \
+ enum events_##name event) \
+{ \
+ bool retval; \
+ \
+ retval = da_event_##name(da_mon, event); \
+ if (!retval) \
+ da_monitor_reset_##name(da_mon); \
+} \
+ \
+/* \
+ * da_handle_event_##name - handle an event \
+ */ \
+static inline void da_handle_event_##name(enum events_##name event) \
+{ \
+ struct da_monitor *da_mon = da_get_monitor_##name(); \
+ bool retval; \
+ \
+ retval = da_monitor_handling_event_##name(da_mon); \
+ if (!retval) \
+ return; \
+ \
+ __da_handle_event_##name(da_mon, event); \
+} \
+ \
+/* \
+ * da_handle_start_event_##name - start monitoring or handle event \
+ * \
+ * This function is used to notify the monitor that the system is returning \
+ * to the initial state, so the monitor can start monitoring in the next event. \
+ * Thus: \
+ * \
+ * If the monitor already started, handle the event. \
+ * If the monitor did not start yet, start the monitor but skip the event. \
+ */ \
+static inline bool da_handle_start_event_##name(enum events_##name event) \
+{ \
+ struct da_monitor *da_mon; \
+ \
+ if (!da_monitor_enabled_##name()) \
+ return 0; \
+ \
+ da_mon = da_get_monitor_##name(); \
+ \
+ if (unlikely(!da_monitoring_##name(da_mon))) { \
+ da_monitor_start_##name(da_mon); \
+ return 0; \
+ } \
+ \
+ __da_handle_event_##name(da_mon, event); \
+ \
+ return 1; \
+} \
+ \
+/* \
+ * da_handle_start_run_event_##name - start monitoring and handle event \
+ * \
+ * This function is used to notify the monitor that the system is in the \
+ * initial state, so the monitor can start monitoring and handling event. \
+ */ \
+static inline bool da_handle_start_run_event_##name(enum events_##name event) \
+{ \
+ struct da_monitor *da_mon; \
+ \
+ if (!da_monitor_enabled_##name()) \
+ return 0; \
+ \
+ da_mon = da_get_monitor_##name(); \
+ \
+ if (unlikely(!da_monitoring_##name(da_mon))) \
+ da_monitor_start_##name(da_mon); \
+ \
+ __da_handle_event_##name(da_mon, event); \
+ \
+ return 1; \
+}
+
+/*
+ * Handle event for per task.
+ */
+#define DECLARE_DA_MON_MONITOR_HANDLER_PER_TASK(name, type) \
+ \
+static inline void \
+__da_handle_event_##name(struct da_monitor *da_mon, struct task_struct *tsk, \
+ enum events_##name event) \
+{ \
+ bool retval; \
+ \
+ retval = da_event_##name(da_mon, tsk, event); \
+ if (!retval) \
+ da_monitor_reset_##name(da_mon); \
+} \
+ \
+/* \
+ * da_handle_event_##name - handle an event \
+ */ \
+static inline void \
+da_handle_event_##name(struct task_struct *tsk, enum events_##name event) \
+{ \
+ struct da_monitor *da_mon = da_get_monitor_##name(tsk); \
+ bool retval; \
+ \
+ retval = da_monitor_handling_event_##name(da_mon); \
+ if (!retval) \
+ return; \
+ \
+ __da_handle_event_##name(da_mon, tsk, event); \
+} \
+ \
+/* \
+ * da_handle_start_event_##name - start monitoring or handle event \
+ * \
+ * This function is used to notify the monitor that the system is returning \
+ * to the initial state, so the monitor can start monitoring in the next event. \
+ * Thus: \
+ * \
+ * If the monitor already started, handle the event. \
+ * If the monitor did not start yet, start the monitor but skip the event. \
+ */ \
+static inline bool \
+da_handle_start_event_##name(struct task_struct *tsk, enum events_##name event) \
+{ \
+ struct da_monitor *da_mon; \
+ \
+ if (!da_monitor_enabled_##name()) \
+ return 0; \
+ \
+ da_mon = da_get_monitor_##name(tsk); \
+ \
+ if (unlikely(!da_monitoring_##name(da_mon))) { \
+ da_monitor_start_##name(da_mon); \
+ return 0; \
+ } \
+ \
+ __da_handle_event_##name(da_mon, tsk, event); \
+ \
+ return 1; \
+}
+
+/*
+ * Entry point for the global monitor.
+ */
+#define DECLARE_DA_MON_GLOBAL(name, type) \
+ \
+DECLARE_AUTOMATA_HELPERS(name, type) \
+DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
+DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
+DECLARE_DA_MON_INIT_GLOBAL(name, type) \
+DECLARE_DA_MON_MONITOR_HANDLER_IMPLICIT(name, type)
+
+/*
+ * Entry point for the per-cpu monitor.
+ */
+#define DECLARE_DA_MON_PER_CPU(name, type) \
+ \
+DECLARE_AUTOMATA_HELPERS(name, type) \
+DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
+DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
+DECLARE_DA_MON_INIT_PER_CPU(name, type) \
+DECLARE_DA_MON_MONITOR_HANDLER_IMPLICIT(name, type)
+
+/*
+ * Entry point for the per-task monitor.
+ */
+#define DECLARE_DA_MON_PER_TASK(name, type) \
+ \
+DECLARE_AUTOMATA_HELPERS(name, type) \
+DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
+DECLARE_DA_MON_MODEL_HANDLER_PER_TASK(name, type) \
+DECLARE_DA_MON_INIT_PER_TASK(name, type) \
+DECLARE_DA_MON_MONITOR_HANDLER_PER_TASK(name, type)