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tracing: Ftrace dynamic ftrace_event_call support
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Add dynamic ftrace_event_call support to ftrace. Trace engines can add
new ftrace_event_call to ftrace on the fly. Each operator function of
the call takes an ftrace_event_call data structure as an argument,
because these functions may be shared among several ftrace_event_calls.

Changes from v13:
 - Define remove_subsystem_dir() always (revirt a2ca5e0), because
   trace_remove_event_call() uses it.
 - Modify syscall tracer because of ftrace_event_call change.

[fweisbec@gmail.com: Fixed conflict against latest tracing/core]

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203453.31965.71901.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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Masami Hiramatsu authored and Frederic Weisbecker committed Aug 26, 2009
1 parent b1cf540 commit bd1a5c8
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Showing 7 changed files with 130 additions and 79 deletions.
19 changes: 10 additions & 9 deletions include/linux/ftrace_event.h
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Original file line number Diff line number Diff line change
Expand Up @@ -112,12 +112,12 @@ struct ftrace_event_call {
struct dentry *dir;
struct trace_event *event;
int enabled;
int (*regfunc)(void *);
void (*unregfunc)(void *);
int (*regfunc)(struct ftrace_event_call *);
void (*unregfunc)(struct ftrace_event_call *);
int id;
int (*raw_init)(void);
int (*show_format)(struct ftrace_event_call *call,
struct trace_seq *s);
int (*raw_init)(struct ftrace_event_call *);
int (*show_format)(struct ftrace_event_call *,
struct trace_seq *);
int (*define_fields)(struct ftrace_event_call *);
struct list_head fields;
int filter_active;
Expand Down Expand Up @@ -147,11 +147,12 @@ enum {
FILTER_PTR_STRING,
};

extern int trace_define_field(struct ftrace_event_call *call,
const char *type, const char *name,
int offset, int size, int is_signed,
int filter_type);
extern int trace_define_common_fields(struct ftrace_event_call *call);
extern int trace_define_field(struct ftrace_event_call *call, char *type,
char *name, int offset, int size, int is_signed,
int filter_type);
extern int trace_add_event_call(struct ftrace_event_call *call);
extern void trace_remove_event_call(struct ftrace_event_call *call);

#define is_signed_type(type) (((type)(-1)) < 0)

Expand Down
4 changes: 2 additions & 2 deletions include/linux/syscalls.h
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Original file line number Diff line number Diff line change
Expand Up @@ -165,7 +165,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
struct trace_event enter_syscall_print_##sname = { \
.trace = print_syscall_enter, \
}; \
static int init_enter_##sname(void) \
static int init_enter_##sname(struct ftrace_event_call *call) \
{ \
int num, id; \
num = syscall_name_to_nr("sys"#sname); \
Expand Down Expand Up @@ -202,7 +202,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
struct trace_event exit_syscall_print_##sname = { \
.trace = print_syscall_exit, \
}; \
static int init_exit_##sname(void) \
static int init_exit_##sname(struct ftrace_event_call *call) \
{ \
int num, id; \
num = syscall_name_to_nr("sys"#sname); \
Expand Down
16 changes: 8 additions & 8 deletions include/trace/ftrace.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -434,7 +434,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
* event_trace_printk(_RET_IP_, "<call>: " <fmt>);
* }
*
* static int ftrace_reg_event_<call>(void)
* static int ftrace_reg_event_<call>(struct ftrace_event_call *unused)
* {
* int ret;
*
Expand All @@ -445,7 +445,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
* return ret;
* }
*
* static void ftrace_unreg_event_<call>(void)
* static void ftrace_unreg_event_<call>(struct ftrace_event_call *unused)
* {
* unregister_trace_<call>(ftrace_event_<call>);
* }
Expand Down Expand Up @@ -478,7 +478,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
* trace_current_buffer_unlock_commit(event, irq_flags, pc);
* }
*
* static int ftrace_raw_reg_event_<call>(void)
* static int ftrace_raw_reg_event_<call>(struct ftrace_event_call *unused)
* {
* int ret;
*
Expand All @@ -489,7 +489,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
* return ret;
* }
*
* static void ftrace_unreg_event_<call>(void)
* static void ftrace_unreg_event_<call>(struct ftrace_event_call *unused)
* {
* unregister_trace_<call>(ftrace_raw_event_<call>);
* }
Expand All @@ -498,7 +498,7 @@ static void ftrace_profile_disable_##call(struct ftrace_event_call *event_call)\
* .trace = ftrace_raw_output_<call>, <-- stage 2
* };
*
* static int ftrace_raw_init_event_<call>(void)
* static int ftrace_raw_init_event_<call>(struct ftrace_event_call *unused)
* {
* int id;
*
Expand Down Expand Up @@ -592,7 +592,7 @@ static void ftrace_raw_event_##call(proto) \
trace_nowake_buffer_unlock_commit(event, irq_flags, pc); \
} \
\
static int ftrace_raw_reg_event_##call(void *ptr) \
static int ftrace_raw_reg_event_##call(struct ftrace_event_call *unused)\
{ \
int ret; \
\
Expand All @@ -603,7 +603,7 @@ static int ftrace_raw_reg_event_##call(void *ptr) \
return ret; \
} \
\
static void ftrace_raw_unreg_event_##call(void *ptr) \
static void ftrace_raw_unreg_event_##call(struct ftrace_event_call *unused)\
{ \
unregister_trace_##call(ftrace_raw_event_##call); \
} \
Expand All @@ -612,7 +612,7 @@ static struct trace_event ftrace_event_type_##call = { \
.trace = ftrace_raw_output_##call, \
}; \
\
static int ftrace_raw_init_event_##call(void) \
static int ftrace_raw_init_event_##call(struct ftrace_event_call *unused)\
{ \
int id; \
\
Expand Down
11 changes: 7 additions & 4 deletions include/trace/syscall.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -39,16 +39,19 @@ void set_syscall_enter_id(int num, int id);
void set_syscall_exit_id(int num, int id);
extern struct trace_event event_syscall_enter;
extern struct trace_event event_syscall_exit;
extern int reg_event_syscall_enter(void *ptr);
extern void unreg_event_syscall_enter(void *ptr);
extern int reg_event_syscall_exit(void *ptr);
extern void unreg_event_syscall_exit(void *ptr);

extern int syscall_enter_format(struct ftrace_event_call *call,
struct trace_seq *s);
extern int syscall_exit_format(struct ftrace_event_call *call,
struct trace_seq *s);
extern int syscall_enter_define_fields(struct ftrace_event_call *call);
extern int syscall_exit_define_fields(struct ftrace_event_call *call);
extern int reg_event_syscall_enter(struct ftrace_event_call *call);
extern void unreg_event_syscall_enter(struct ftrace_event_call *call);
extern int reg_event_syscall_exit(struct ftrace_event_call *call);
extern void unreg_event_syscall_exit(struct ftrace_event_call *call);
extern int
ftrace_format_syscall(struct ftrace_event_call *call, struct trace_seq *s);
enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags);
enum print_line_t print_syscall_exit(struct trace_iterator *iter, int flags);
#endif
Expand Down
121 changes: 84 additions & 37 deletions kernel/trace/trace_events.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,8 +27,8 @@ DEFINE_MUTEX(event_mutex);

LIST_HEAD(ftrace_events);

int trace_define_field(struct ftrace_event_call *call, const char *type,
const char *name, int offset, int size, int is_signed,
int trace_define_field(struct ftrace_event_call *call, char *type,
char *name, int offset, int size, int is_signed,
int filter_type)
{
struct ftrace_event_field *field;
Expand Down Expand Up @@ -92,9 +92,7 @@ int trace_define_common_fields(struct ftrace_event_call *call)
}
EXPORT_SYMBOL_GPL(trace_define_common_fields);

#ifdef CONFIG_MODULES

static void trace_destroy_fields(struct ftrace_event_call *call)
void trace_destroy_fields(struct ftrace_event_call *call)
{
struct ftrace_event_field *field, *next;

Expand All @@ -106,8 +104,6 @@ static void trace_destroy_fields(struct ftrace_event_call *call)
}
}

#endif /* CONFIG_MODULES */

static void ftrace_event_enable_disable(struct ftrace_event_call *call,
int enable)
{
Expand All @@ -116,14 +112,14 @@ static void ftrace_event_enable_disable(struct ftrace_event_call *call,
if (call->enabled) {
call->enabled = 0;
tracing_stop_cmdline_record();
call->unregfunc(call->data);
call->unregfunc(call);
}
break;
case 1:
if (!call->enabled) {
call->enabled = 1;
tracing_start_cmdline_record();
call->regfunc(call->data);
call->regfunc(call);
}
break;
}
Expand Down Expand Up @@ -991,27 +987,43 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
return 0;
}

#define for_each_event(event, start, end) \
for (event = start; \
(unsigned long)event < (unsigned long)end; \
event++)
static int __trace_add_event_call(struct ftrace_event_call *call)
{
struct dentry *d_events;
int ret;

#ifdef CONFIG_MODULES
if (!call->name)
return -EINVAL;

static LIST_HEAD(ftrace_module_file_list);
if (call->raw_init) {
ret = call->raw_init(call);
if (ret < 0) {
if (ret != -ENOSYS)
pr_warning("Could not initialize trace "
"events/%s\n", call->name);
return ret;
}
}

/*
* Modules must own their file_operations to keep up with
* reference counting.
*/
struct ftrace_module_file_ops {
struct list_head list;
struct module *mod;
struct file_operations id;
struct file_operations enable;
struct file_operations format;
struct file_operations filter;
};
d_events = event_trace_events_dir();
if (!d_events)
return -ENOENT;

list_add(&call->list, &ftrace_events);
return event_create_dir(call, d_events, &ftrace_event_id_fops,
&ftrace_enable_fops, &ftrace_event_filter_fops,
&ftrace_event_format_fops);
}

/* Add an additional event_call dynamically */
int trace_add_event_call(struct ftrace_event_call *call)
{
int ret;
mutex_lock(&event_mutex);
ret = __trace_add_event_call(call);
mutex_unlock(&event_mutex);
return ret;
}

static void remove_subsystem_dir(const char *name)
{
Expand Down Expand Up @@ -1039,6 +1051,48 @@ static void remove_subsystem_dir(const char *name)
}
}

static void __trace_remove_event_call(struct ftrace_event_call *call)
{
ftrace_event_enable_disable(call, 0);
if (call->event)
__unregister_ftrace_event(call->event);
debugfs_remove_recursive(call->dir);
list_del(&call->list);
trace_destroy_fields(call);
destroy_preds(call);
remove_subsystem_dir(call->system);
}

/* Remove an event_call */
void trace_remove_event_call(struct ftrace_event_call *call)
{
mutex_lock(&event_mutex);
__trace_remove_event_call(call);
mutex_unlock(&event_mutex);
}

#define for_each_event(event, start, end) \
for (event = start; \
(unsigned long)event < (unsigned long)end; \
event++)

#ifdef CONFIG_MODULES

static LIST_HEAD(ftrace_module_file_list);

/*
* Modules must own their file_operations to keep up with
* reference counting.
*/
struct ftrace_module_file_ops {
struct list_head list;
struct module *mod;
struct file_operations id;
struct file_operations enable;
struct file_operations format;
struct file_operations filter;
};

static struct ftrace_module_file_ops *
trace_create_file_ops(struct module *mod)
{
Expand Down Expand Up @@ -1096,7 +1150,7 @@ static void trace_module_add_events(struct module *mod)
if (!call->name)
continue;
if (call->raw_init) {
ret = call->raw_init();
ret = call->raw_init(call);
if (ret < 0) {
if (ret != -ENOSYS)
pr_warning("Could not initialize trace "
Expand Down Expand Up @@ -1131,14 +1185,7 @@ static void trace_module_remove_events(struct module *mod)
list_for_each_entry_safe(call, p, &ftrace_events, list) {
if (call->mod == mod) {
found = true;
ftrace_event_enable_disable(call, 0);
if (call->event)
__unregister_ftrace_event(call->event);
debugfs_remove_recursive(call->dir);
list_del(&call->list);
trace_destroy_fields(call);
destroy_preds(call);
remove_subsystem_dir(call->system);
__trace_remove_event_call(call);
}
}

Expand Down Expand Up @@ -1256,7 +1303,7 @@ static __init int event_trace_init(void)
if (!call->name)
continue;
if (call->raw_init) {
ret = call->raw_init();
ret = call->raw_init(call);
if (ret < 0) {
if (ret != -ENOSYS)
pr_warning("Could not initialize trace "
Expand Down
18 changes: 9 additions & 9 deletions kernel/trace/trace_export.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -117,27 +117,27 @@ ftrace_format_##call(struct ftrace_event_call *unused, \
#define TRACE_FIELD_SPECIAL(type_item, item, len, cmd) \
cmd;

static int ftrace_raw_init_event(struct ftrace_event_call *event_call)
{
INIT_LIST_HEAD(&event_call->fields);
init_preds(event_call);
return 0;
}

#undef TRACE_EVENT_FORMAT
#define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt) \
int ftrace_define_fields_##call(struct ftrace_event_call *event_call); \
static int ftrace_raw_init_event_##call(void); \
\
struct ftrace_event_call __used \
__attribute__((__aligned__(4))) \
__attribute__((section("_ftrace_events"))) event_##call = { \
.name = #call, \
.id = proto, \
.system = __stringify(TRACE_SYSTEM), \
.raw_init = ftrace_raw_init_event_##call, \
.raw_init = ftrace_raw_init_event, \
.show_format = ftrace_format_##call, \
.define_fields = ftrace_define_fields_##call, \
}; \
static int ftrace_raw_init_event_##call(void) \
{ \
INIT_LIST_HEAD(&event_##call.fields); \
init_preds(&event_##call); \
return 0; \
} \
};

#undef TRACE_EVENT_FORMAT_NOFILTER
#define TRACE_EVENT_FORMAT_NOFILTER(call, proto, args, fmt, tstruct, \
Expand Down
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