| /* SPDX-License-Identifier: GPL-2.0-only */ |
| #ifndef _LINUX_TRACEPOINT_H |
| #define _LINUX_TRACEPOINT_H |
| |
| /* |
| * Kernel Tracepoint API. |
| * |
| * See Documentation/trace/tracepoints.rst. |
| * |
| * Copyright (C) 2008-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| * |
| * Heavily inspired from the Linux Kernel Markers. |
| */ |
| |
| #include <linux/smp.h> |
| #include <linux/srcu.h> |
| #include <linux/errno.h> |
| #include <linux/types.h> |
| #include <linux/cpumask.h> |
| #include <linux/rcupdate.h> |
| #include <linux/tracepoint-defs.h> |
| #include <linux/static_call.h> |
| |
| struct module; |
| struct tracepoint; |
| struct notifier_block; |
| |
| struct trace_eval_map { |
| const char *system; |
| const char *eval_string; |
| unsigned long eval_value; |
| }; |
| |
| #define TRACEPOINT_DEFAULT_PRIO 10 |
| |
| extern struct srcu_struct tracepoint_srcu; |
| |
| extern int |
| tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data); |
| extern int |
| tracepoint_probe_register_prio(struct tracepoint *tp, void *probe, void *data, |
| int prio); |
| extern int |
| tracepoint_probe_register_prio_may_exist(struct tracepoint *tp, void *probe, void *data, |
| int prio); |
| extern int |
| tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data); |
| static inline int |
| tracepoint_probe_register_may_exist(struct tracepoint *tp, void *probe, |
| void *data) |
| { |
| return tracepoint_probe_register_prio_may_exist(tp, probe, data, |
| TRACEPOINT_DEFAULT_PRIO); |
| } |
| extern void |
| for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv), |
| void *priv); |
| |
| #ifdef CONFIG_MODULES |
| struct tp_module { |
| struct list_head list; |
| struct module *mod; |
| }; |
| |
| bool trace_module_has_bad_taint(struct module *mod); |
| extern int register_tracepoint_module_notifier(struct notifier_block *nb); |
| extern int unregister_tracepoint_module_notifier(struct notifier_block *nb); |
| #else |
| static inline bool trace_module_has_bad_taint(struct module *mod) |
| { |
| return false; |
| } |
| static inline |
| int register_tracepoint_module_notifier(struct notifier_block *nb) |
| { |
| return 0; |
| } |
| static inline |
| int unregister_tracepoint_module_notifier(struct notifier_block *nb) |
| { |
| return 0; |
| } |
| #endif /* CONFIG_MODULES */ |
| |
| /* |
| * tracepoint_synchronize_unregister must be called between the last tracepoint |
| * probe unregistration and the end of module exit to make sure there is no |
| * caller executing a probe when it is freed. |
| */ |
| #ifdef CONFIG_TRACEPOINTS |
| static inline void tracepoint_synchronize_unregister(void) |
| { |
| synchronize_srcu(&tracepoint_srcu); |
| synchronize_rcu(); |
| } |
| #else |
| static inline void tracepoint_synchronize_unregister(void) |
| { } |
| #endif |
| |
| #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS |
| extern int syscall_regfunc(void); |
| extern void syscall_unregfunc(void); |
| #endif /* CONFIG_HAVE_SYSCALL_TRACEPOINTS */ |
| |
| #ifndef PARAMS |
| #define PARAMS(args...) args |
| #endif |
| |
| #define TRACE_DEFINE_ENUM(x) |
| #define TRACE_DEFINE_SIZEOF(x) |
| |
| #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS |
| static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) |
| { |
| return offset_to_ptr(p); |
| } |
| |
| #define __TRACEPOINT_ENTRY(name) \ |
| asm(" .section \"__tracepoints_ptrs\", \"a\" \n" \ |
| " .balign 4 \n" \ |
| " .long __tracepoint_" #name " - . \n" \ |
| " .previous \n") |
| #else |
| static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) |
| { |
| return *p; |
| } |
| |
| #define __TRACEPOINT_ENTRY(name) \ |
| static tracepoint_ptr_t __tracepoint_ptr_##name __used \ |
| __section("__tracepoints_ptrs") = &__tracepoint_##name |
| #endif |
| |
| #endif /* _LINUX_TRACEPOINT_H */ |
| |
| /* |
| * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include |
| * file ifdef protection. |
| * This is due to the way trace events work. If a file includes two |
| * trace event headers under one "CREATE_TRACE_POINTS" the first include |
| * will override the TRACE_EVENT and break the second include. |
| */ |
| |
| #ifndef DECLARE_TRACE |
| |
| #define TP_PROTO(args...) args |
| #define TP_ARGS(args...) args |
| #define TP_CONDITION(args...) args |
| |
| /* |
| * Individual subsystem my have a separate configuration to |
| * enable their tracepoints. By default, this file will create |
| * the tracepoints if CONFIG_TRACEPOINT is defined. If a subsystem |
| * wants to be able to disable its tracepoints from being created |
| * it can define NOTRACE before including the tracepoint headers. |
| */ |
| #if defined(CONFIG_TRACEPOINTS) && !defined(NOTRACE) |
| #define TRACEPOINTS_ENABLED |
| #endif |
| |
| #ifdef TRACEPOINTS_ENABLED |
| |
| #ifdef CONFIG_HAVE_STATIC_CALL |
| #define __DO_TRACE_CALL(name, args) \ |
| do { \ |
| struct tracepoint_func *it_func_ptr; \ |
| void *__data; \ |
| it_func_ptr = \ |
| rcu_dereference_raw((&__tracepoint_##name)->funcs); \ |
| if (it_func_ptr) { \ |
| __data = (it_func_ptr)->data; \ |
| static_call(tp_func_##name)(__data, args); \ |
| } \ |
| } while (0) |
| #else |
| #define __DO_TRACE_CALL(name, args) __traceiter_##name(NULL, args) |
| #endif /* CONFIG_HAVE_STATIC_CALL */ |
| |
| /* |
| * it_func[0] is never NULL because there is at least one element in the array |
| * when the array itself is non NULL. |
| */ |
| #define __DO_TRACE(name, args, cond, rcuidle) \ |
| do { \ |
| int __maybe_unused __idx = 0; \ |
| \ |
| if (!(cond)) \ |
| return; \ |
| \ |
| /* srcu can't be used from NMI */ \ |
| WARN_ON_ONCE(rcuidle && in_nmi()); \ |
| \ |
| /* keep srcu and sched-rcu usage consistent */ \ |
| preempt_disable_notrace(); \ |
| \ |
| /* \ |
| * For rcuidle callers, use srcu since sched-rcu \ |
| * doesn't work from the idle path. \ |
| */ \ |
| if (rcuidle) { \ |
| __idx = srcu_read_lock_notrace(&tracepoint_srcu);\ |
| rcu_irq_enter_irqson(); \ |
| } \ |
| \ |
| __DO_TRACE_CALL(name, TP_ARGS(args)); \ |
| \ |
| if (rcuidle) { \ |
| rcu_irq_exit_irqson(); \ |
| srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\ |
| } \ |
| \ |
| preempt_enable_notrace(); \ |
| } while (0) |
| |
| #ifndef MODULE |
| #define __DECLARE_TRACE_RCU(name, proto, args, cond) \ |
| static inline void trace_##name##_rcuidle(proto) \ |
| { \ |
| if (static_key_false(&__tracepoint_##name.key)) \ |
| __DO_TRACE(name, \ |
| TP_ARGS(args), \ |
| TP_CONDITION(cond), 1); \ |
| } |
| #else |
| #define __DECLARE_TRACE_RCU(name, proto, args, cond) |
| #endif |
| |
| /* |
| * Make sure the alignment of the structure in the __tracepoints section will |
| * not add unwanted padding between the beginning of the section and the |
| * structure. Force alignment to the same alignment as the section start. |
| * |
| * When lockdep is enabled, we make sure to always do the RCU portions of |
| * the tracepoint code, regardless of whether tracing is on. However, |
| * don't check if the condition is false, due to interaction with idle |
| * instrumentation. This lets us find RCU issues triggered with tracepoints |
| * even when this tracepoint is off. This code has no purpose other than |
| * poking RCU a bit. |
| */ |
| #define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ |
| extern int __traceiter_##name(data_proto); \ |
| DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name); \ |
| extern struct tracepoint __tracepoint_##name; \ |
| static inline void trace_##name(proto) \ |
| { \ |
| if (static_key_false(&__tracepoint_##name.key)) \ |
| __DO_TRACE(name, \ |
| TP_ARGS(args), \ |
| TP_CONDITION(cond), 0); \ |
| if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ |
| rcu_read_lock_sched_notrace(); \ |
| rcu_dereference_sched(__tracepoint_##name.funcs);\ |
| rcu_read_unlock_sched_notrace(); \ |
| } \ |
| } \ |
| __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \ |
| PARAMS(cond)) \ |
| static inline int \ |
| register_trace_##name(void (*probe)(data_proto), void *data) \ |
| { \ |
| return tracepoint_probe_register(&__tracepoint_##name, \ |
| (void *)probe, data); \ |
| } \ |
| static inline int \ |
| register_trace_prio_##name(void (*probe)(data_proto), void *data,\ |
| int prio) \ |
| { \ |
| return tracepoint_probe_register_prio(&__tracepoint_##name, \ |
| (void *)probe, data, prio); \ |
| } \ |
| static inline int \ |
| unregister_trace_##name(void (*probe)(data_proto), void *data) \ |
| { \ |
| return tracepoint_probe_unregister(&__tracepoint_##name,\ |
| (void *)probe, data); \ |
| } \ |
| static inline void \ |
| check_trace_callback_type_##name(void (*cb)(data_proto)) \ |
| { \ |
| } \ |
| static inline bool \ |
| trace_##name##_enabled(void) \ |
| { \ |
| return static_key_false(&__tracepoint_##name.key); \ |
| } |
| |
| /* |
| * We have no guarantee that gcc and the linker won't up-align the tracepoint |
| * structures, so we create an array of pointers that will be used for iteration |
| * on the tracepoints. |
| */ |
| #define DEFINE_TRACE_FN(_name, _reg, _unreg, proto, args) \ |
| static const char __tpstrtab_##_name[] \ |
| __section("__tracepoints_strings") = #_name; \ |
| extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name); \ |
| int __traceiter_##_name(void *__data, proto); \ |
| struct tracepoint __tracepoint_##_name __used \ |
| __section("__tracepoints") = { \ |
| .name = __tpstrtab_##_name, \ |
| .key = STATIC_KEY_INIT_FALSE, \ |
| .static_call_key = &STATIC_CALL_KEY(tp_func_##_name), \ |
| .static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \ |
| .iterator = &__traceiter_##_name, \ |
| .regfunc = _reg, \ |
| .unregfunc = _unreg, \ |
| .funcs = NULL }; \ |
| __TRACEPOINT_ENTRY(_name); \ |
| int __traceiter_##_name(void *__data, proto) \ |
| { \ |
| struct tracepoint_func *it_func_ptr; \ |
| void *it_func; \ |
| \ |
| it_func_ptr = \ |
| rcu_dereference_raw((&__tracepoint_##_name)->funcs); \ |
| if (it_func_ptr) { \ |
| do { \ |
| it_func = READ_ONCE((it_func_ptr)->func); \ |
| __data = (it_func_ptr)->data; \ |
| ((void(*)(void *, proto))(it_func))(__data, args); \ |
| } while ((++it_func_ptr)->func); \ |
| } \ |
| return 0; \ |
| } \ |
| DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); |
| |
| #define DEFINE_TRACE(name, proto, args) \ |
| DEFINE_TRACE_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args)); |
| |
| #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \ |
| EXPORT_SYMBOL_GPL(__tracepoint_##name); \ |
| EXPORT_SYMBOL_GPL(__traceiter_##name); \ |
| EXPORT_STATIC_CALL_GPL(tp_func_##name) |
| #define EXPORT_TRACEPOINT_SYMBOL(name) \ |
| EXPORT_SYMBOL(__tracepoint_##name); \ |
| EXPORT_SYMBOL(__traceiter_##name); \ |
| EXPORT_STATIC_CALL(tp_func_##name) |
| |
| |
| #else /* !TRACEPOINTS_ENABLED */ |
| #define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ |
| static inline void trace_##name(proto) \ |
| { } \ |
| static inline void trace_##name##_rcuidle(proto) \ |
| { } \ |
| static inline int \ |
| register_trace_##name(void (*probe)(data_proto), \ |
| void *data) \ |
| { \ |
| return -ENOSYS; \ |
| } \ |
| static inline int \ |
| unregister_trace_##name(void (*probe)(data_proto), \ |
| void *data) \ |
| { \ |
| return -ENOSYS; \ |
| } \ |
| static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \ |
| { \ |
| } \ |
| static inline bool \ |
| trace_##name##_enabled(void) \ |
| { \ |
| return false; \ |
| } |
| |
| #define DEFINE_TRACE_FN(name, reg, unreg, proto, args) |
| #define DEFINE_TRACE(name, proto, args) |
| #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) |
| #define EXPORT_TRACEPOINT_SYMBOL(name) |
| |
| #endif /* TRACEPOINTS_ENABLED */ |
| |
| #ifdef CONFIG_TRACING |
| /** |
| * tracepoint_string - register constant persistent string to trace system |
| * @str - a constant persistent string that will be referenced in tracepoints |
| * |
| * If constant strings are being used in tracepoints, it is faster and |
| * more efficient to just save the pointer to the string and reference |
| * that with a printf "%s" instead of saving the string in the ring buffer |
| * and wasting space and time. |
| * |
| * The problem with the above approach is that userspace tools that read |
| * the binary output of the trace buffers do not have access to the string. |
| * Instead they just show the address of the string which is not very |
| * useful to users. |
| * |
| * With tracepoint_string(), the string will be registered to the tracing |
| * system and exported to userspace via the debugfs/tracing/printk_formats |
| * file that maps the string address to the string text. This way userspace |
| * tools that read the binary buffers have a way to map the pointers to |
| * the ASCII strings they represent. |
| * |
| * The @str used must be a constant string and persistent as it would not |
| * make sense to show a string that no longer exists. But it is still fine |
| * to be used with modules, because when modules are unloaded, if they |
| * had tracepoints, the ring buffers are cleared too. As long as the string |
| * does not change during the life of the module, it is fine to use |
| * tracepoint_string() within a module. |
| */ |
| #define tracepoint_string(str) \ |
| ({ \ |
| static const char *___tp_str __tracepoint_string = str; \ |
| ___tp_str; \ |
| }) |
| #define __tracepoint_string __used __section("__tracepoint_str") |
| #else |
| /* |
| * tracepoint_string() is used to save the string address for userspace |
| * tracing tools. When tracing isn't configured, there's no need to save |
| * anything. |
| */ |
| # define tracepoint_string(str) str |
| # define __tracepoint_string |
| #endif |
| |
| #define DECLARE_TRACE(name, proto, args) \ |
| __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \ |
| cpu_online(raw_smp_processor_id()), \ |
| PARAMS(void *__data, proto)) |
| |
| #define DECLARE_TRACE_CONDITION(name, proto, args, cond) \ |
| __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \ |
| cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \ |
| PARAMS(void *__data, proto)) |
| |
| #define TRACE_EVENT_FLAGS(event, flag) |
| |
| #define TRACE_EVENT_PERF_PERM(event, expr...) |
| |
| #endif /* DECLARE_TRACE */ |
| |
| #ifndef TRACE_EVENT |
| /* |
| * For use with the TRACE_EVENT macro: |
| * |
| * We define a tracepoint, its arguments, its printk format |
| * and its 'fast binary record' layout. |
| * |
| * Firstly, name your tracepoint via TRACE_EVENT(name : the |
| * 'subsystem_event' notation is fine. |
| * |
| * Think about this whole construct as the |
| * 'trace_sched_switch() function' from now on. |
| * |
| * |
| * TRACE_EVENT(sched_switch, |
| * |
| * * |
| * * A function has a regular function arguments |
| * * prototype, declare it via TP_PROTO(): |
| * * |
| * |
| * TP_PROTO(struct rq *rq, struct task_struct *prev, |
| * struct task_struct *next), |
| * |
| * * |
| * * Define the call signature of the 'function'. |
| * * (Design sidenote: we use this instead of a |
| * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.) |
| * * |
| * |
| * TP_ARGS(rq, prev, next), |
| * |
| * * |
| * * Fast binary tracing: define the trace record via |
| * * TP_STRUCT__entry(). You can think about it like a |
| * * regular C structure local variable definition. |
| * * |
| * * This is how the trace record is structured and will |
| * * be saved into the ring buffer. These are the fields |
| * * that will be exposed to user-space in |
| * * /sys/kernel/debug/tracing/events/<*>/format. |
| * * |
| * * The declared 'local variable' is called '__entry' |
| * * |
| * * __field(pid_t, prev_pid) is equivalent to a standard declaration: |
| * * |
| * * pid_t prev_pid; |
| * * |
| * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to: |
| * * |
| * * char prev_comm[TASK_COMM_LEN]; |
| * * |
| * |
| * TP_STRUCT__entry( |
| * __array( char, prev_comm, TASK_COMM_LEN ) |
| * __field( pid_t, prev_pid ) |
| * __field( int, prev_prio ) |
| * __array( char, next_comm, TASK_COMM_LEN ) |
| * __field( pid_t, next_pid ) |
| * __field( int, next_prio ) |
| * ), |
| * |
| * * |
| * * Assign the entry into the trace record, by embedding |
| * * a full C statement block into TP_fast_assign(). You |
| * * can refer to the trace record as '__entry' - |
| * * otherwise you can put arbitrary C code in here. |
| * * |
| * * Note: this C code will execute every time a trace event |
| * * happens, on an active tracepoint. |
| * * |
| * |
| * TP_fast_assign( |
| * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); |
| * __entry->prev_pid = prev->pid; |
| * __entry->prev_prio = prev->prio; |
| * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); |
| * __entry->next_pid = next->pid; |
| * __entry->next_prio = next->prio; |
| * ), |
| * |
| * * |
| * * Formatted output of a trace record via TP_printk(). |
| * * This is how the tracepoint will appear under ftrace |
| * * plugins that make use of this tracepoint. |
| * * |
| * * (raw-binary tracing wont actually perform this step.) |
| * * |
| * |
| * TP_printk("task %s:%d [%d] ==> %s:%d [%d]", |
| * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio, |
| * __entry->next_comm, __entry->next_pid, __entry->next_prio), |
| * |
| * ); |
| * |
| * This macro construct is thus used for the regular printk format |
| * tracing setup, it is used to construct a function pointer based |
| * tracepoint callback (this is used by programmatic plugins and |
| * can also by used by generic instrumentation like SystemTap), and |
| * it is also used to expose a structured trace record in |
| * /sys/kernel/debug/tracing/events/. |
| * |
| * A set of (un)registration functions can be passed to the variant |
| * TRACE_EVENT_FN to perform any (un)registration work. |
| */ |
| |
| #define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print) |
| #define DEFINE_EVENT(template, name, proto, args) \ |
| DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
| #define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)\ |
| DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
| #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ |
| DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
| #define DEFINE_EVENT_CONDITION(template, name, proto, \ |
| args, cond) \ |
| DECLARE_TRACE_CONDITION(name, PARAMS(proto), \ |
| PARAMS(args), PARAMS(cond)) |
| |
| #define TRACE_EVENT(name, proto, args, struct, assign, print) \ |
| DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
| #define TRACE_EVENT_FN(name, proto, args, struct, \ |
| assign, print, reg, unreg) \ |
| DECLARE_TRACE(name, PARAMS(proto), PARAMS(args)) |
| #define TRACE_EVENT_FN_COND(name, proto, args, cond, struct, \ |
| assign, print, reg, unreg) \ |
| DECLARE_TRACE_CONDITION(name, PARAMS(proto), \ |
| PARAMS(args), PARAMS(cond)) |
| #define TRACE_EVENT_CONDITION(name, proto, args, cond, \ |
| struct, assign, print) \ |
| DECLARE_TRACE_CONDITION(name, PARAMS(proto), \ |
| PARAMS(args), PARAMS(cond)) |
| |
| #define TRACE_EVENT_FLAGS(event, flag) |
| |
| #define TRACE_EVENT_PERF_PERM(event, expr...) |
| |
| #define DECLARE_EVENT_NOP(name, proto, args) \ |
| static inline void trace_##name(proto) \ |
| { } \ |
| static inline bool trace_##name##_enabled(void) \ |
| { \ |
| return false; \ |
| } |
| |
| #define TRACE_EVENT_NOP(name, proto, args, struct, assign, print) \ |
| DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args)) |
| |
| #define DECLARE_EVENT_CLASS_NOP(name, proto, args, tstruct, assign, print) |
| #define DEFINE_EVENT_NOP(template, name, proto, args) \ |
| DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args)) |
| |
| #endif /* ifdef TRACE_EVENT (see note above) */ |