diff options
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/rv/Kconfig | 1 | ||||
| -rw-r--r-- | kernel/trace/rv/Makefile | 1 | ||||
| -rw-r--r-- | kernel/trace/rv/monitors/rtapp/Kconfig | 2 | ||||
| -rw-r--r-- | kernel/trace/rv/monitors/wakeup/Kconfig | 16 | ||||
| -rw-r--r-- | kernel/trace/rv/monitors/wakeup/wakeup.c | 153 | ||||
| -rw-r--r-- | kernel/trace/rv/monitors/wakeup/wakeup.h | 92 | ||||
| -rw-r--r-- | kernel/trace/rv/monitors/wakeup/wakeup_trace.h | 14 | ||||
| -rw-r--r-- | kernel/trace/rv/rv_trace.h | 1 |
8 files changed, 279 insertions, 1 deletions
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig index 3884b14df375..4d3a14a0bac2 100644 --- a/kernel/trace/rv/Kconfig +++ b/kernel/trace/rv/Kconfig @@ -76,6 +76,7 @@ source "kernel/trace/rv/monitors/opid/Kconfig" source "kernel/trace/rv/monitors/rtapp/Kconfig" source "kernel/trace/rv/monitors/pagefault/Kconfig" source "kernel/trace/rv/monitors/sleep/Kconfig" +source "kernel/trace/rv/monitors/wakeup/Kconfig" # Add new rtapp monitors here source "kernel/trace/rv/monitors/stall/Kconfig" diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile index 94498da35b37..c2c0e4142eb4 100644 --- a/kernel/trace/rv/Makefile +++ b/kernel/trace/rv/Makefile @@ -20,6 +20,7 @@ obj-$(CONFIG_RV_MON_OPID) += monitors/opid/opid.o obj-$(CONFIG_RV_MON_STALL) += monitors/stall/stall.o obj-$(CONFIG_RV_MON_DEADLINE) += monitors/deadline/deadline.o obj-$(CONFIG_RV_MON_NOMISS) += monitors/nomiss/nomiss.o +obj-$(CONFIG_RV_MON_WAKEUP) += monitors/wakeup/wakeup.o # Add new monitors here obj-$(CONFIG_RV_REACTORS) += rv_reactors.o obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o diff --git a/kernel/trace/rv/monitors/rtapp/Kconfig b/kernel/trace/rv/monitors/rtapp/Kconfig index 1ce9370a9ba8..1fcd7a400ded 100644 --- a/kernel/trace/rv/monitors/rtapp/Kconfig +++ b/kernel/trace/rv/monitors/rtapp/Kconfig @@ -1,6 +1,6 @@ config RV_MON_RTAPP depends on RV - depends on RV_PER_TASK_MONITORS >= 2 + depends on RV_PER_TASK_MONITORS >= 3 bool "rtapp monitor" help Collection of monitors to check for common problems with real-time diff --git a/kernel/trace/rv/monitors/wakeup/Kconfig b/kernel/trace/rv/monitors/wakeup/Kconfig new file mode 100644 index 000000000000..98f618f0e01d --- /dev/null +++ b/kernel/trace/rv/monitors/wakeup/Kconfig @@ -0,0 +1,16 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +config RV_MON_WAKEUP + depends on RV + depends on RV_MON_RTAPP + depends on HAVE_SYSCALL_TRACEPOINTS + default y + select LTL_MON_EVENTS_ID + bool "wakeup monitor" + help + This monitor detects a lower-priority task waking up a + higher-priority task. The RV_MON_SLEEP monitor already + detects this case, but this monitor detects in the context + of the waker task instead. This and RV_MON_SLEEP can be + enabled together to get the stacktrace of both the waker + task and the wakee task. diff --git a/kernel/trace/rv/monitors/wakeup/wakeup.c b/kernel/trace/rv/monitors/wakeup/wakeup.c new file mode 100644 index 000000000000..01b47416f24e --- /dev/null +++ b/kernel/trace/rv/monitors/wakeup/wakeup.c @@ -0,0 +1,153 @@ +// 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> + +#define MODULE_NAME "wakeup" + +#include <trace/events/syscalls.h> +#include <trace/events/sched.h> +#include <trace/events/lock.h> +#include <uapi/linux/futex.h> + +#include <rv_trace.h> +#include <monitors/rtapp/rtapp.h> + + +#ifndef __NR_futex +#define __NR_futex (-__COUNTER__) +#endif +#ifndef __NR_futex_time64 +#define __NR_futex_time64 (-__COUNTER__) +#endif + +#include "wakeup.h" +#include <rv/ltl_monitor.h> + +static void ltl_atoms_fetch(struct task_struct *task, struct ltl_monitor *mon) +{ + /* + * This includes "actual" real-time tasks and also PI-boosted + * tasks. A task being PI-boosted means it is blocking an "actual" + * real-task, therefore it should also obey the monitor's rule, + * otherwise the "actual" real-task may be delayed. + */ + ltl_atom_set(mon, LTL_RT, rt_or_dl_task(task)); +} + +static void ltl_atoms_init(struct task_struct *task, struct ltl_monitor *mon, bool task_creation) +{ + ltl_atom_set(mon, LTL_WOKEN_BY_LOWER_PRIO, false); + ltl_atom_set(mon, LTL_WOKEN_BY_SOFTIRQ, false); + + if (task_creation) { + ltl_atom_set(mon, LTL_BLOCK_ON_RT_MUTEX, false); + ltl_atom_set(mon, LTL_FUTEX_LOCK_PI, false); + } + + ltl_atom_set(mon, LTL_USER_THREAD, !(task->flags & PF_KTHREAD)); +} + +static void handle_sched_waking(void *data, struct task_struct *task) +{ + if (in_task()) { + if (current->prio > task->prio) + ltl_atom_pulse(task, LTL_WOKEN_BY_LOWER_PRIO, true); + } else if (in_serving_softirq()) { + ltl_atom_pulse(task, LTL_WOKEN_BY_SOFTIRQ, true); + } +} + +static void handle_contention_begin(void *data, void *lock, unsigned int flags) +{ + if (flags & LCB_F_RT) + ltl_atom_update(current, LTL_BLOCK_ON_RT_MUTEX, true); +} + +static void handle_contention_end(void *data, void *lock, int ret) +{ + ltl_atom_update(current, LTL_BLOCK_ON_RT_MUTEX, false); +} + +static void handle_sys_enter(void *data, struct pt_regs *regs, long id) +{ + unsigned long args[6]; + int op, cmd; + + switch (id) { + case __NR_futex: + case __NR_futex_time64: + syscall_get_arguments(current, regs, args); + op = args[1]; + cmd = op & FUTEX_CMD_MASK; + + switch (cmd) { + case FUTEX_LOCK_PI: + case FUTEX_LOCK_PI2: + ltl_atom_update(current, LTL_FUTEX_LOCK_PI, true); + break; + } + break; + } +} + +static void handle_sys_exit(void *data, struct pt_regs *regs, long ret) +{ + ltl_atom_update(current, LTL_FUTEX_LOCK_PI, false); +} + +static int enable_wakeup(void) +{ + int retval; + + retval = ltl_monitor_init(); + if (retval) + return retval; + + rv_attach_trace_probe("rtapp_wakeup", sched_waking, handle_sched_waking); + rv_attach_trace_probe("rtapp_wakeup", contention_begin, handle_contention_begin); + rv_attach_trace_probe("rtapp_wakeup", contention_end, handle_contention_end); + rv_attach_trace_probe("rtapp_wakeup", sys_enter, handle_sys_enter); + rv_attach_trace_probe("rtapp_wakeup", sys_exit, handle_sys_exit); + + return 0; +} + +static void disable_wakeup(void) +{ + rv_detach_trace_probe("rtapp_wakeup", sched_waking, handle_sched_waking); + rv_detach_trace_probe("rtapp_wakeup", contention_begin, handle_contention_begin); + rv_detach_trace_probe("rtapp_wakeup", contention_end, handle_contention_end); + rv_detach_trace_probe("rtapp_wakeup", sys_enter, handle_sys_enter); + rv_detach_trace_probe("rtapp_wakeup", sys_exit, handle_sys_exit); + + ltl_monitor_destroy(); +} + +static struct rv_monitor rv_wakeup = { + .name = "wakeup", + .description = "Monitor that real-time tasks are not woken by lower-priority tasks", + .enable = enable_wakeup, + .disable = disable_wakeup, +}; + +static int __init register_wakeup(void) +{ + return rv_register_monitor(&rv_wakeup, &rv_rtapp); +} + +static void __exit unregister_wakeup(void) +{ + rv_unregister_monitor(&rv_wakeup); +} + +module_init(register_wakeup); +module_exit(unregister_wakeup); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Nam Cao <namcao@linutronix.de>"); +MODULE_DESCRIPTION("Monitor that real-time tasks are not woken by lower-priority tasks"); diff --git a/kernel/trace/rv/monitors/wakeup/wakeup.h b/kernel/trace/rv/monitors/wakeup/wakeup.h new file mode 100644 index 000000000000..6f80da64e0e1 --- /dev/null +++ b/kernel/trace/rv/monitors/wakeup/wakeup.h @@ -0,0 +1,92 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * C implementation of Buchi automaton, automatically generated by + * tools/verification/rvgen from the linear temporal logic specification. + * For further information, see kernel documentation: + * Documentation/trace/rv/linear_temporal_logic.rst + */ + +#include <linux/rv.h> + +#define MONITOR_NAME wakeup + +enum ltl_atom { + LTL_BLOCK_ON_RT_MUTEX, + LTL_FUTEX_LOCK_PI, + LTL_RT, + LTL_USER_THREAD, + LTL_WOKEN_BY_LOWER_PRIO, + LTL_WOKEN_BY_SOFTIRQ, + LTL_NUM_ATOM +}; +static_assert(LTL_NUM_ATOM <= RV_MAX_LTL_ATOM); + +static const char *ltl_atom_str(enum ltl_atom atom) +{ + static const char *const names[] = { + "bl_on_rt_mu", + "fu_lo_pi", + "rt", + "us_th", + "wo_lo_pr", + "wo_so", + }; + + return names[atom]; +} + +enum ltl_buchi_state { + S0, + RV_NUM_BA_STATES +}; +static_assert(RV_NUM_BA_STATES <= RV_MAX_BA_STATES); + +static void ltl_start(struct task_struct *task, struct ltl_monitor *mon) +{ + bool woken_by_softirq = test_bit(LTL_WOKEN_BY_SOFTIRQ, mon->atoms); + bool woken_by_lower_prio = test_bit(LTL_WOKEN_BY_LOWER_PRIO, mon->atoms); + bool user_thread = test_bit(LTL_USER_THREAD, mon->atoms); + bool rt = test_bit(LTL_RT, mon->atoms); + bool futex_lock_pi = test_bit(LTL_FUTEX_LOCK_PI, mon->atoms); + bool block_on_rt_mutex = test_bit(LTL_BLOCK_ON_RT_MUTEX, mon->atoms); + bool val9 = block_on_rt_mutex || futex_lock_pi; + bool val6 = !woken_by_softirq; + bool val5 = !woken_by_lower_prio; + bool val8 = val5 && val6; + bool val10 = val8 || val9; + bool val3 = !user_thread; + bool val2 = !rt; + bool val4 = val2 || val3; + bool val11 = val4 || val10; + + if (val11) + __set_bit(S0, mon->states); +} + +static void +ltl_possible_next_states(struct ltl_monitor *mon, unsigned int state, unsigned long *next) +{ + bool woken_by_softirq = test_bit(LTL_WOKEN_BY_SOFTIRQ, mon->atoms); + bool woken_by_lower_prio = test_bit(LTL_WOKEN_BY_LOWER_PRIO, mon->atoms); + bool user_thread = test_bit(LTL_USER_THREAD, mon->atoms); + bool rt = test_bit(LTL_RT, mon->atoms); + bool futex_lock_pi = test_bit(LTL_FUTEX_LOCK_PI, mon->atoms); + bool block_on_rt_mutex = test_bit(LTL_BLOCK_ON_RT_MUTEX, mon->atoms); + bool val9 = block_on_rt_mutex || futex_lock_pi; + bool val6 = !woken_by_softirq; + bool val5 = !woken_by_lower_prio; + bool val8 = val5 && val6; + bool val10 = val8 || val9; + bool val3 = !user_thread; + bool val2 = !rt; + bool val4 = val2 || val3; + bool val11 = val4 || val10; + + switch (state) { + case S0: + if (val11) + __set_bit(S0, next); + break; + } +} diff --git a/kernel/trace/rv/monitors/wakeup/wakeup_trace.h b/kernel/trace/rv/monitors/wakeup/wakeup_trace.h new file mode 100644 index 000000000000..7e056183f920 --- /dev/null +++ b/kernel/trace/rv/monitors/wakeup/wakeup_trace.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Snippet to be included in rv_trace.h + */ + +#ifdef CONFIG_RV_MON_WAKEUP +DEFINE_EVENT(event_ltl_monitor_id, event_wakeup, + TP_PROTO(struct task_struct *task, char *states, char *atoms, char *next), + TP_ARGS(task, states, atoms, next)); +DEFINE_EVENT(error_ltl_monitor_id, error_wakeup, + TP_PROTO(struct task_struct *task), + TP_ARGS(task)); +#endif /* CONFIG_RV_MON_WAKEUP */ diff --git a/kernel/trace/rv/rv_trace.h b/kernel/trace/rv/rv_trace.h index 9622c269789c..2f8a932432c9 100644 --- a/kernel/trace/rv/rv_trace.h +++ b/kernel/trace/rv/rv_trace.h @@ -241,6 +241,7 @@ DECLARE_EVENT_CLASS(error_ltl_monitor_id, ); #include <monitors/pagefault/pagefault_trace.h> #include <monitors/sleep/sleep_trace.h> +#include <monitors/wakeup/wakeup_trace.h> // Add new monitors based on CONFIG_LTL_MON_EVENTS_ID here #endif /* CONFIG_LTL_MON_EVENTS_ID */ |