diff options
| -rw-r--r-- | include/linux/ftrace_event.h | 11 | ||||
| -rw-r--r-- | include/trace/ftrace.h | 4 | ||||
| -rw-r--r-- | kernel/trace/Makefile | 1 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 181 | ||||
| -rw-r--r-- | kernel/trace/trace_events.c | 21 | ||||
| -rw-r--r-- | kernel/trace/trace_events_trigger.c | 278 | ||||
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 4 |
7 files changed, 495 insertions, 5 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 8c9b7a1..211e7ad 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -264,6 +264,7 @@ enum { FTRACE_EVENT_FL_NO_SET_FILTER_BIT, FTRACE_EVENT_FL_SOFT_MODE_BIT, FTRACE_EVENT_FL_SOFT_DISABLED_BIT, + FTRACE_EVENT_FL_TRIGGER_MODE_BIT, }; /* @@ -275,6 +276,7 @@ enum { * SOFT_MODE - The event is enabled/disabled by SOFT_DISABLED * SOFT_DISABLED - When set, do not trace the event (even though its * tracepoint may be enabled) + * TRIGGER_MODE - When set, invoke the triggers associated with the event */ enum { FTRACE_EVENT_FL_ENABLED = (1 << FTRACE_EVENT_FL_ENABLED_BIT), @@ -283,6 +285,7 @@ enum { FTRACE_EVENT_FL_NO_SET_FILTER = (1 << FTRACE_EVENT_FL_NO_SET_FILTER_BIT), FTRACE_EVENT_FL_SOFT_MODE = (1 << FTRACE_EVENT_FL_SOFT_MODE_BIT), FTRACE_EVENT_FL_SOFT_DISABLED = (1 << FTRACE_EVENT_FL_SOFT_DISABLED_BIT), + FTRACE_EVENT_FL_TRIGGER_MODE = (1 << FTRACE_EVENT_FL_TRIGGER_MODE_BIT), }; struct ftrace_event_file { @@ -292,6 +295,7 @@ struct ftrace_event_file { struct dentry *dir; struct trace_array *tr; struct ftrace_subsystem_dir *system; + struct list_head triggers; /* * 32 bit flags: @@ -299,6 +303,7 @@ struct ftrace_event_file { * bit 1: enabled cmd record * bit 2: enable/disable with the soft disable bit * bit 3: soft disabled + * bit 4: trigger enabled * * Note: The bits must be set atomically to prevent races * from other writers. Reads of flags do not need to be in @@ -310,6 +315,7 @@ struct ftrace_event_file { */ unsigned long flags; atomic_t sm_ref; /* soft-mode reference counter */ + atomic_t tm_ref; /* trigger-mode reference counter */ }; #define __TRACE_EVENT_FLAGS(name, value) \ @@ -337,6 +343,10 @@ struct ftrace_event_file { #define MAX_FILTER_STR_VAL 256 /* Should handle KSYM_SYMBOL_LEN */ +enum event_trigger_type { + ETT_NONE = (0), +}; + extern void destroy_preds(struct ftrace_event_file *file); extern void destroy_call_preds(struct ftrace_event_call *call); extern int filter_match_preds(struct event_filter *filter, void *rec); @@ -347,6 +357,7 @@ extern int filter_check_discard(struct ftrace_event_file *file, void *rec, extern int call_filter_check_discard(struct ftrace_event_call *call, void *rec, struct ring_buffer *buffer, struct ring_buffer_event *event); +extern void event_triggers_call(struct ftrace_event_file *file); enum { FILTER_OTHER = 0, diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 5c38606..0a48bff 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -539,6 +539,10 @@ ftrace_raw_event_##call(void *__data, proto) \ int __data_size; \ int pc; \ \ + if (test_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, \ + &ftrace_file->flags)) \ + event_triggers_call(ftrace_file); \ + \ if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, \ &ftrace_file->flags)) \ return; \ diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index d7e2068..1378e84 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -50,6 +50,7 @@ ifeq ($(CONFIG_PERF_EVENTS),y) obj-$(CONFIG_EVENT_TRACING) += trace_event_perf.o endif obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o +obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o obj-$(CONFIG_TRACEPOINTS) += power-traces.o ifeq ($(CONFIG_PM_RUNTIME),y) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index ea189e0..9775e51 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1028,9 +1028,190 @@ extern void trace_event_enable_cmd_record(bool enable); extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr); extern int event_trace_del_tracer(struct trace_array *tr); +static inline void *event_file_data(struct file *filp) +{ + return ACCESS_ONCE(file_inode(filp)->i_private); +} + extern struct mutex event_mutex; extern struct list_head ftrace_events; +extern const struct file_operations event_trigger_fops; + +extern int register_trigger_cmds(void); +extern void clear_event_triggers(struct trace_array *tr); + +struct event_trigger_data { + unsigned long count; + int ref; + struct event_trigger_ops *ops; + struct event_command *cmd_ops; + struct event_filter *filter; + char *filter_str; + void *private_data; + struct list_head list; +}; + +/** + * struct event_trigger_ops - callbacks for trace event triggers + * + * The methods in this structure provide per-event trigger hooks for + * various trigger operations. + * + * All the methods below, except for @init() and @free(), must be + * implemented. + * + * @func: The trigger 'probe' function called when the triggering + * event occurs. The data passed into this callback is the data + * that was supplied to the event_command @reg() function that + * registered the trigger (see struct event_command). + * + * @init: An optional initialization function called for the trigger + * when the trigger is registered (via the event_command reg() + * function). This can be used to perform per-trigger + * initialization such as incrementing a per-trigger reference + * count, for instance. This is usually implemented by the + * generic utility function @event_trigger_init() (see + * trace_event_triggers.c). + * + * @free: An optional de-initialization function called for the + * trigger when the trigger is unregistered (via the + * event_command @reg() function). This can be used to perform + * per-trigger de-initialization such as decrementing a + * per-trigger reference count and freeing corresponding trigger + * data, for instance. This is usually implemented by the + * generic utility function @event_trigger_free() (see + * trace_event_triggers.c). + * + * @print: The callback function invoked to have the trigger print + * itself. This is usually implemented by a wrapper function + * that calls the generic utility function @event_trigger_print() + * (see trace_event_triggers.c). + */ +struct event_trigger_ops { + void (*func)(struct event_trigger_data *data); + int (*init)(struct event_trigger_ops *ops, + struct event_trigger_data *data); + void (*free)(struct event_trigger_ops *ops, + struct event_trigger_data *data); + int (*print)(struct seq_file *m, + struct event_trigger_ops *ops, + struct event_trigger_data *data); +}; + +/** + * struct event_command - callbacks and data members for event commands + * + * Event commands are invoked by users by writing the command name + * into the 'trigger' file associated with a trace event. The + * parameters associated with a specific invocation of an event + * command are used to create an event trigger instance, which is + * added to the list of trigger instances associated with that trace + * event. When the event is hit, the set of triggers associated with + * that event is invoked. + * + * The data members in this structure provide per-event command data + * for various event commands. + * + * All the data members below, except for @post_trigger, must be set + * for each event command. + * + * @name: The unique name that identifies the event command. This is + * the name used when setting triggers via trigger files. + * + * @trigger_type: A unique id that identifies the event command + * 'type'. This value has two purposes, the first to ensure that + * only one trigger of the same type can be set at a given time + * for a particular event e.g. it doesn't make sense to have both + * a traceon and traceoff trigger attached to a single event at + * the same time, so traceon and traceoff have the same type + * though they have different names. The @trigger_type value is + * also used as a bit value for deferring the actual trigger + * action until after the current event is finished. Some + * commands need to do this if they themselves log to the trace + * buffer (see the @post_trigger() member below). @trigger_type + * values are defined by adding new values to the trigger_type + * enum in include/linux/ftrace_event.h. + * + * @post_trigger: A flag that says whether or not this command needs + * to have its action delayed until after the current event has + * been closed. Some triggers need to avoid being invoked while + * an event is currently in the process of being logged, since + * the trigger may itself log data into the trace buffer. Thus + * we make sure the current event is committed before invoking + * those triggers. To do that, the trigger invocation is split + * in two - the first part checks the filter using the current + * trace record; if a command has the @post_trigger flag set, it + * sets a bit for itself in the return value, otherwise it + * directly invokes the trigger. Once all commands have been + * either invoked or set their return flag, the current record is + * either committed or discarded. At that point, if any commands + * have deferred their triggers, those commands are finally + * invoked following the close of the current event. In other + * words, if the event_trigger_ops @func() probe implementation + * itself logs to the trace buffer, this flag should be set, + * otherwise it can be left unspecified. + * + * All the methods below, except for @set_filter(), must be + * implemented. + * + * @func: The callback function responsible for parsing and + * registering the trigger written to the 'trigger' file by the + * user. It allocates the trigger instance and registers it with + * the appropriate trace event. It makes use of the other + * event_command callback functions to orchestrate this, and is + * usually implemented by the generic utility function + * @event_trigger_callback() (see trace_event_triggers.c). + * + * @reg: Adds the trigger to the list of triggers associated with the + * event, and enables the event trigger itself, after + * initializing it (via the event_trigger_ops @init() function). + * This is also where commands can use the @trigger_type value to + * make the decision as to whether or not multiple instances of + * the trigger should be allowed. This is usually implemented by + * the generic utility function @register_trigger() (see + * trace_event_triggers.c). + * + * @unreg: Removes the trigger from the list of triggers associated + * with the event, and disables the event trigger itself, after + * initializing it (via the event_trigger_ops @free() function). + * This is usually implemented by the generic utility function + * @unregister_trigger() (see trace_event_triggers.c). + * + * @set_filter: An optional function called to parse and set a filter + * for the trigger. If no @set_filter() method is set for the + * event command, filters set by the user for the command will be + * ignored. This is usually implemented by the generic utility + * function @set_trigger_filter() (see trace_event_triggers.c). + * + * @get_trigger_ops: The callback function invoked to retrieve the + * event_trigger_ops implementation associated with the command. + */ +struct event_command { + struct list_head list; + char *name; + enum event_trigger_type trigger_type; + bool post_trigger; + int (*func)(struct event_command *cmd_ops, + struct ftrace_event_file *file, + char *glob, char *cmd, char *params); + int (*reg)(char *glob, + struct event_trigger_ops *ops, + struct event_trigger_data *data, + struct ftrace_event_file *file); + void (*unreg)(char *glob, + struct event_trigger_ops *ops, + struct event_trigger_data *data, + struct ftrace_event_file *file); + int (*set_filter)(char *filter_str, + struct event_trigger_data *data, + struct ftrace_event_file *file); + struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param); +}; + +extern int trace_event_enable_disable(struct ftrace_event_file *file, + int enable, int soft_disable); + extern const char *__start___trace_bprintk_fmt[]; extern const char *__stop___trace_bprintk_fmt[]; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index a11800a..442775c 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -342,6 +342,12 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file, return ret; } +int trace_event_enable_disable(struct ftrace_event_file *file, + int enable, int soft_disable) +{ + return __ftrace_event_enable_disable(file, enable, soft_disable); +} + static int ftrace_event_enable_disable(struct ftrace_event_file *file, int enable) { @@ -421,11 +427,6 @@ static void remove_subsystem(struct ftrace_subsystem_dir *dir) } } -static void *event_file_data(struct file *filp) -{ - return ACCESS_ONCE(file_inode(filp)->i_private); -} - static void remove_event_file_dir(struct ftrace_event_file *file) { struct dentry *dir = file->dir; @@ -1549,6 +1550,9 @@ event_create_dir(struct dentry *parent, struct ftrace_event_file *file) trace_create_file("filter", 0644, file->dir, file, &ftrace_event_filter_fops); + trace_create_file("trigger", 0644, file->dir, file, + &event_trigger_fops); + trace_create_file("format", 0444, file->dir, call, &ftrace_event_format_fops); @@ -1645,6 +1649,8 @@ trace_create_new_event(struct ftrace_event_call *call, file->event_call = call; file->tr = tr; atomic_set(&file->sm_ref, 0); + atomic_set(&file->tm_ref, 0); + INIT_LIST_HEAD(&file->triggers); list_add(&file->list, &tr->events); return file; @@ -2311,6 +2317,9 @@ int event_trace_del_tracer(struct trace_array *tr) { mutex_lock(&event_mutex); + /* Disable any event triggers and associated soft-disabled events */ + clear_event_triggers(tr); + /* Disable any running events */ __ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0); @@ -2377,6 +2386,8 @@ static __init int event_trace_enable(void) register_event_cmds(); + register_trigger_cmds(); + return 0; } diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c new file mode 100644 index 0000000..60a6a6d --- /dev/null +++ b/kernel/trace/trace_events_trigger.c @@ -0,0 +1,278 @@ +/* + * trace_events_trigger - trace event triggers + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com> + */ + +#include <linux/module.h> +#include <linux/ctype.h> +#include <linux/mutex.h> +#include <linux/slab.h> + +#include "trace.h" + +static LIST_HEAD(trigger_commands); +static DEFINE_MUTEX(trigger_cmd_mutex); + +/** + * event_triggers_call - Call triggers associated with a trace event + * @file: The ftrace_event_file associated with the event + * + * For each trigger associated with an event, invoke the trigger + * function registered with the associated trigger command. + * + * Called from tracepoint handlers (with rcu_read_lock_sched() held). + * + * Return: an enum event_trigger_type value containing a set bit for + * any trigger that should be deferred, ETT_NONE if nothing to defer. + */ +void event_triggers_call(struct ftrace_event_file *file) +{ + struct event_trigger_data *data; + + if (list_empty(&file->triggers)) + return; + + list_for_each_entry_rcu(data, &file->triggers, list) + data->ops->func(data); +} +EXPORT_SYMBOL_GPL(event_triggers_call); + +static void *trigger_next(struct seq_file *m, void *t, loff_t *pos) +{ + struct ftrace_event_file *event_file = event_file_data(m->private); + + return seq_list_next(t, &event_file->triggers, pos); +} + +static void *trigger_start(struct seq_file *m, loff_t *pos) +{ + struct ftrace_event_file *event_file; + + /* ->stop() is called even if ->start() fails */ + mutex_lock(&event_mutex); + event_file = event_file_data(m->private); + if (unlikely(!event_file)) + return ERR_PTR(-ENODEV); + + return seq_list_start(&event_file->triggers, *pos); +} + +static void trigger_stop(struct seq_file *m, void *t) +{ + mutex_unlock(&event_mutex); +} + +static int trigger_show(struct seq_file *m, void *v) +{ + struct event_trigger_data *data; + + data = list_entry(v, struct event_trigger_data, list); + data->ops->print(m, data->ops, data); + + return 0; +} + +static const struct seq_operations event_triggers_seq_ops = { + .start = trigger_start, + .next = trigger_next, + .stop = trigger_stop, + .show = trigger_show, +}; + +static int event_trigger_regex_open(struct inode *inode, struct file *file) +{ + int ret = 0; + + mutex_lock(&event_mutex); + + if (unlikely(!event_file_data(file))) { + mutex_unlock(&event_mutex); + return -ENODEV; + } + + if (file->f_mode & FMODE_READ) { + ret = seq_open(file, &event_triggers_seq_ops); + if (!ret) { + struct seq_file *m = file->private_data; + m->private = file; + } + } + + mutex_unlock(&event_mutex); + + return ret; +} + +static int trigger_process_regex(struct ftrace_event_file *file, char *buff) +{ + char *command, *next = buff; + struct event_command *p; + int ret = -EINVAL; + + command = strsep(&next, ": \t"); + command = (command[0] != '!') ? command : command + 1; + + mutex_lock(&trigger_cmd_mutex); + list_for_each_entry(p, &trigger_commands, list) { + if (strcmp(p->name, command) == 0) { + ret = p->func(p, file, buff, command, next); + goto out_unlock; + } + } + out_unlock: + mutex_unlock(&trigger_cmd_mutex); + + return ret; +} + +static ssize_t event_trigger_regex_write(struct file *file, + const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct ftrace_event_file *event_file; + ssize_t ret; + char *buf; + + if (!cnt) + return 0; + + if (cnt >= PAGE_SIZE) + return -EINVAL; + + buf = (char *)__get_free_page(GFP_TEMPORARY); + if (!buf) + return -ENOMEM; + + if (copy_from_user(buf, ubuf, cnt)) { + free_page((unsigned long)buf); + return -EFAULT; + } + buf[cnt] = '\0'; + strim(buf); + + mutex_lock(&event_mutex); + event_file = event_file_data(file); + if (unlikely(!event_file)) { + mutex_unlock(&event_mutex); + free_page((unsigned long)buf); + return -ENODEV; + } + ret = trigger_process_regex(event_file, buf); + mutex_unlock(&event_mutex); + + free_page((unsigned long)buf); + if (ret < 0) + goto out; + + *ppos += cnt; + ret = cnt; + out: + return ret; +} + +static int event_trigger_regex_release(struct inode *inode, struct file *file) +{ + mutex_lock(&event_mutex); + + if (file->f_mode & FMODE_READ) + seq_release(inode, file); + + mutex_unlock(&event_mutex); + + return 0; +} + +static ssize_t +event_trigger_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return event_trigger_regex_write(filp, ubuf, cnt, ppos); +} + +static int +event_trigger_open(struct inode *inode, struct file *filp) +{ + return event_trigger_regex_open(inode, filp); +} + +static int +event_trigger_release(struct inode *inode, struct file *file) +{ + return event_trigger_regex_release(inode, file); +} + +const struct file_operations event_trigger_fops = { + .open = event_trigger_open, + .read = seq_read, + .write = event_trigger_write, + .llseek = ftrace_filter_lseek, + .release = event_trigger_release, +}; + +static int trace_event_trigger_enable_disable(struct ftrace_event_file *file, + int trigger_enable) +{ + int ret = 0; + + if (trigger_enable) { + if (atomic_inc_return(&file->tm_ref) > 1) + return ret; + set_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &file->flags); + ret = trace_event_enable_disable(file, 1, 1); + } else { + if (atomic_dec_return(&file->tm_ref) > 0) + return ret; + clear_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &file->flags); + ret = trace_event_enable_disable(file, 0, 1); + } + + return ret; +} + +/** + * clear_event_triggers - Clear all triggers associated with a trace array + * @tr: The trace array to clear + * + * For each trigger, the triggering event has its tm_ref decremented + * via trace_event_trigger_enable_disable(), and any associated event + * (in the case of enable/disable_event triggers) will have its sm_ref + * decremented via free()->trace_event_enable_disable(). That + * combination effectively reverses the soft-mode/trigger state added + * by trigger registration. + * + * Must be called with event_mutex held. + */ +void +clear_event_triggers(struct trace_array *tr) +{ + struct ftrace_event_file *file; + + list_for_each_entry(file, &tr->events, list) { + struct event_trigger_data *data; + list_for_each_entry_rcu(data, &file->triggers, list) { + trace_event_trigger_enable_disable(file, 0); + if (data->ops->free) + data->ops->free(data->ops, data); + } + } +} + +__init int register_trigger_cmds(void) +{ + return 0; +} diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index ea90eb5..936ec39 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -321,6 +321,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) if (!ftrace_file) return; + if (test_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &ftrace_file->flags)) + event_triggers_call(ftrace_file); if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) return; @@ -369,6 +371,8 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) if (!ftrace_file) return; + if (test_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &ftrace_file->flags)) + event_triggers_call(ftrace_file); if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) return; |