android_kernel_xiaomi_sm8350/include/linux/tracepoint.h
Lai Jiangshan 7f5b774275 rcu: Fix tracepoints & lockdep false positive
tracepoint.h uses rcu_dereference(), which triggers this warning:

[    0.701161] ===================================================
[    0.702211] [ INFO: suspicious rcu_dereference_check() usage. ]
[    0.702716] ---------------------------------------------------
[    0.703203] include/trace/events/workqueue.h:68 invoked rcu_dereference_check() without protection!
[    0.703971] [ 0.703990] other info that might help us debug this:
[    0.703993]
[    0.705590]
[    0.705604] rcu_scheduler_active = 1, debug_locks = 0
[    0.706712] 1 lock held by swapper/1:
[    0.707229]  #0:  (cpu_add_remove_lock){+.+.+.}, at: [<c0142f54>] cpu_maps_update_begin+0x14/0x20
[    0.710097]
[    0.710106] stack backtrace:
[    0.712602] Pid: 1, comm: swapper Not tainted 2.6.34-rc1-tip-01613-g72662bb #168
[    0.713231] Call Trace:
[    0.713997]  [<c017174d>] lockdep_rcu_dereference+0x9d/0xb0
[    0.714746]  [<c015a117>] create_workqueue_thread+0x107/0x110
[    0.715353]  [<c015aee0>] ? worker_thread+0x0/0x340
[    0.715845]  [<c015a8e8>] __create_workqueue_key+0x138/0x240
[    0.716427]  [<c0142f92>] ? cpu_maps_update_done+0x12/0x20
[    0.717012]  [<c086b12f>] init_workqueues+0x6f/0x80
[    0.717530]  [<c08576d2>] kernel_init+0x102/0x1f0
[    0.717570]  [<c08575d0>] ? kernel_init+0x0/0x1f0
[    0.718944]  [<c01030fa>] kernel_thread_helper+0x6/0x10

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B9F48AD.4000404@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-16 10:10:40 +01:00

296 lines
8.9 KiB
C

#ifndef _LINUX_TRACEPOINT_H
#define _LINUX_TRACEPOINT_H
/*
* Kernel Tracepoint API.
*
* See Documentation/trace/tracepoints.txt.
*
* (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
*
* Heavily inspired from the Linux Kernel Markers.
*
* This file is released under the GPLv2.
* See the file COPYING for more details.
*/
#include <linux/types.h>
#include <linux/rcupdate.h>
struct module;
struct tracepoint;
struct tracepoint {
const char *name; /* Tracepoint name */
int state; /* State. */
void (*regfunc)(void);
void (*unregfunc)(void);
void **funcs;
} __attribute__((aligned(32))); /*
* Aligned on 32 bytes because it is
* globally visible and gcc happily
* align these on the structure size.
* Keep in sync with vmlinux.lds.h.
*/
#ifndef DECLARE_TRACE
#define TP_PROTO(args...) args
#define TP_ARGS(args...) args
#ifdef CONFIG_TRACEPOINTS
/*
* 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(tp, proto, args) \
do { \
void **it_func; \
\
rcu_read_lock_sched_notrace(); \
it_func = rcu_dereference_sched((tp)->funcs); \
if (it_func) { \
do { \
((void(*)(proto))(*it_func))(args); \
} while (*(++it_func)); \
} \
rcu_read_unlock_sched_notrace(); \
} while (0)
/*
* 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.
*/
#define DECLARE_TRACE(name, proto, args) \
extern struct tracepoint __tracepoint_##name; \
static inline void trace_##name(proto) \
{ \
if (unlikely(__tracepoint_##name.state)) \
__DO_TRACE(&__tracepoint_##name, \
TP_PROTO(proto), TP_ARGS(args)); \
} \
static inline int register_trace_##name(void (*probe)(proto)) \
{ \
return tracepoint_probe_register(#name, (void *)probe); \
} \
static inline int unregister_trace_##name(void (*probe)(proto)) \
{ \
return tracepoint_probe_unregister(#name, (void *)probe);\
}
#define DEFINE_TRACE_FN(name, reg, unreg) \
static const char __tpstrtab_##name[] \
__attribute__((section("__tracepoints_strings"))) = #name; \
struct tracepoint __tracepoint_##name \
__attribute__((section("__tracepoints"), aligned(32))) = \
{ __tpstrtab_##name, 0, reg, unreg, NULL }
#define DEFINE_TRACE(name) \
DEFINE_TRACE_FN(name, NULL, NULL);
#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
EXPORT_SYMBOL_GPL(__tracepoint_##name)
#define EXPORT_TRACEPOINT_SYMBOL(name) \
EXPORT_SYMBOL(__tracepoint_##name)
extern void tracepoint_update_probe_range(struct tracepoint *begin,
struct tracepoint *end);
#else /* !CONFIG_TRACEPOINTS */
#define DECLARE_TRACE(name, proto, args) \
static inline void _do_trace_##name(struct tracepoint *tp, proto) \
{ } \
static inline void trace_##name(proto) \
{ } \
static inline int register_trace_##name(void (*probe)(proto)) \
{ \
return -ENOSYS; \
} \
static inline int unregister_trace_##name(void (*probe)(proto)) \
{ \
return -ENOSYS; \
}
#define DEFINE_TRACE_FN(name, reg, unreg)
#define DEFINE_TRACE(name)
#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
#define EXPORT_TRACEPOINT_SYMBOL(name)
static inline void tracepoint_update_probe_range(struct tracepoint *begin,
struct tracepoint *end)
{ }
#endif /* CONFIG_TRACEPOINTS */
#endif /* DECLARE_TRACE */
/*
* Connect a probe to a tracepoint.
* Internal API, should not be used directly.
*/
extern int tracepoint_probe_register(const char *name, void *probe);
/*
* Disconnect a probe from a tracepoint.
* Internal API, should not be used directly.
*/
extern int tracepoint_probe_unregister(const char *name, void *probe);
extern int tracepoint_probe_register_noupdate(const char *name, void *probe);
extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe);
extern void tracepoint_probe_update_all(void);
struct tracepoint_iter {
struct module *module;
struct tracepoint *tracepoint;
};
extern void tracepoint_iter_start(struct tracepoint_iter *iter);
extern void tracepoint_iter_next(struct tracepoint_iter *iter);
extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
struct tracepoint *begin, struct tracepoint *end);
/*
* 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.
*/
static inline void tracepoint_synchronize_unregister(void)
{
synchronize_sched();
}
#define PARAMS(args...) args
#endif /* _LINUX_TRACEPOINT_H */
/*
* Note: we keep the TRACE_EVENT 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 TRACE_EVENT
/*
* For use with the TRACE_EVENT macro:
*
* We define a tracepoint, its arguments, its printk format
* and its 'fast binay 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_prid) is equivalent to a standard declariton:
* *
* * 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_PRINT(template, name, proto, args, print) \
DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
#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))
#endif /* ifdef TRACE_EVENT (see note above) */