Commit f6180773 authored by Steven Rostedt's avatar Steven Rostedt
Browse files

ftrace: add command interface for function selection



Allow for other tracers to add their own commands for function
selection. This interface gives a trace the ability to name a
command for function selection. Right now it is pretty limited
in what it offers, but this is a building step for more features.

The :mod: command is converted to this interface and also serves
as a template for other implementations.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
parent e68746a2
......@@ -95,6 +95,13 @@ stack_trace_sysctl(struct ctl_table *table, int write,
loff_t *ppos);
#endif
struct ftrace_func_command {
struct list_head list;
char *name;
int (*func)(char *func, char *cmd,
char *params, int enable);
};
#ifdef CONFIG_DYNAMIC_FTRACE
/* asm/ftrace.h must be defined for archs supporting dynamic ftrace */
#include <asm/ftrace.h>
......@@ -119,6 +126,9 @@ struct dyn_ftrace {
int ftrace_force_update(void);
void ftrace_set_filter(unsigned char *buf, int len, int reset);
int register_ftrace_command(struct ftrace_func_command *cmd);
int unregister_ftrace_command(struct ftrace_func_command *cmd);
/* defined in arch */
extern int ftrace_ip_converted(unsigned long ip);
extern int ftrace_dyn_arch_init(void *data);
......@@ -202,6 +212,12 @@ extern void ftrace_enable_daemon(void);
# define ftrace_disable_daemon() do { } while (0)
# define ftrace_enable_daemon() do { } while (0)
static inline void ftrace_release(void *start, unsigned long size) { }
static inline int register_ftrace_command(struct ftrace_func_command *cmd)
{
}
static inline int unregister_ftrace_command(char *cmd_name)
{
}
#endif /* CONFIG_DYNAMIC_FTRACE */
/* totally disable ftrace - can not re-enable after this */
......
......@@ -1239,9 +1239,93 @@ static void ftrace_match_module_records(char *buff, char *mod, int enable)
spin_unlock(&ftrace_lock);
}
/*
* We register the module command as a template to show others how
* to register the a command as well.
*/
static int
ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
{
char *mod;
/*
* cmd == 'mod' because we only registered this func
* for the 'mod' ftrace_func_command.
* But if you register one func with multiple commands,
* you can tell which command was used by the cmd
* parameter.
*/
/* we must have a module name */
if (!param)
return -EINVAL;
mod = strsep(&param, ":");
if (!strlen(mod))
return -EINVAL;
ftrace_match_module_records(func, mod, enable);
return 0;
}
static struct ftrace_func_command ftrace_mod_cmd = {
.name = "mod",
.func = ftrace_mod_callback,
};
static int __init ftrace_mod_cmd_init(void)
{
return register_ftrace_command(&ftrace_mod_cmd);
}
device_initcall(ftrace_mod_cmd_init);
static LIST_HEAD(ftrace_commands);
static DEFINE_MUTEX(ftrace_cmd_mutex);
int register_ftrace_command(struct ftrace_func_command *cmd)
{
struct ftrace_func_command *p;
int ret = 0;
mutex_lock(&ftrace_cmd_mutex);
list_for_each_entry(p, &ftrace_commands, list) {
if (strcmp(cmd->name, p->name) == 0) {
ret = -EBUSY;
goto out_unlock;
}
}
list_add(&cmd->list, &ftrace_commands);
out_unlock:
mutex_unlock(&ftrace_cmd_mutex);
return ret;
}
int unregister_ftrace_command(struct ftrace_func_command *cmd)
{
struct ftrace_func_command *p, *n;
int ret = -ENODEV;
mutex_lock(&ftrace_cmd_mutex);
list_for_each_entry_safe(p, n, &ftrace_commands, list) {
if (strcmp(cmd->name, p->name) == 0) {
ret = 0;
list_del_init(&p->list);
goto out_unlock;
}
}
out_unlock:
mutex_unlock(&ftrace_cmd_mutex);
return ret;
}
static int ftrace_process_regex(char *buff, int len, int enable)
{
char *func, *mod, *command, *next = buff;
struct ftrace_func_command *p;
char *func, *command, *next = buff;
int ret = -EINVAL;
func = strsep(&next, ":");
......@@ -1250,21 +1334,21 @@ static int ftrace_process_regex(char *buff, int len, int enable)
return 0;
}
/* command fonud */
/* command found */
command = strsep(&next, ":");
if (strcmp(command, "mod") == 0) {
/* only match modules */
if (!next)
return -EINVAL;
mod = strsep(&next, ":");
ftrace_match_module_records(func, mod, enable);
return 0;
mutex_lock(&ftrace_cmd_mutex);
list_for_each_entry(p, &ftrace_commands, list) {
if (strcmp(p->name, command) == 0) {
ret = p->func(func, command, next, enable);
goto out_unlock;
}
}
out_unlock:
mutex_unlock(&ftrace_cmd_mutex);
return -EINVAL;
return ret;
}
static ssize_t
......
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