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author | Daniel Bristot de Oliveira <bristot@kernel.org> | 2022-07-29 11:38:43 +0200 |
---|---|---|
committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-07-30 20:01:28 +0200 |
commit | 792575348ff70e05c6040d02fce38e949ef92c37 (patch) | |
tree | 253285c43e4c648ba170015817e2a02a34f5926f /include/rv | |
parent | rv/include: Add helper functions for deterministic automata (diff) | |
download | linux-792575348ff70e05c6040d02fce38e949ef92c37.tar.xz linux-792575348ff70e05c6040d02fce38e949ef92c37.zip |
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.h | 541 |
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) |