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linuxdebug/include/linux/tracepoint.h

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/* 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_TRACEPOINTS 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);\
ct_irq_enter_irqson(); \
} \
\
__DO_TRACE_CALL(name, TP_ARGS(args)); \
\
if (rcuidle) { \
ct_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 test if RCU is
* "watching" regardless if the tracepoint is enabled or not. Tracepoints
* require RCU to be active, and it should always warn at the tracepoint
* site if it is not watching, as it will need to be active when the
* tracepoint is enabled.
*/
#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)) { \
WARN_ON_ONCE(!rcu_is_watching()); \
} \
} \
__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) */
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