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-rw-r--r--kernel/trace/trace_events_trigger.c1997
1 files changed, 1997 insertions, 0 deletions
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
new file mode 100644
index 0000000000..46439e3bce
--- /dev/null
+++ b/kernel/trace/trace_events_trigger.c
@@ -0,0 +1,1997 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace_events_trigger - trace event triggers
+ *
+ * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
+ */
+
+#include <linux/security.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+
+#include "trace.h"
+
+static LIST_HEAD(trigger_commands);
+static DEFINE_MUTEX(trigger_cmd_mutex);
+
+void trigger_data_free(struct event_trigger_data *data)
+{
+ if (data->cmd_ops->set_filter)
+ data->cmd_ops->set_filter(NULL, data, NULL);
+
+ /* make sure current triggers exit before free */
+ tracepoint_synchronize_unregister();
+
+ kfree(data);
+}
+
+/**
+ * event_triggers_call - Call triggers associated with a trace event
+ * @file: The trace_event_file associated with the event
+ * @buffer: The ring buffer that the event is being written to
+ * @rec: The trace entry for the event, NULL for unconditional invocation
+ * @event: The event meta data in the ring buffer
+ *
+ * For each trigger associated with an event, invoke the trigger
+ * function registered with the associated trigger command. If rec is
+ * non-NULL, it means that the trigger requires further processing and
+ * shouldn't be unconditionally invoked. If rec is non-NULL and the
+ * trigger has a filter associated with it, rec will checked against
+ * the filter and if the record matches the trigger will be invoked.
+ * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
+ * in any case until the current event is written, the trigger
+ * function isn't invoked but the bit associated with the deferred
+ * trigger is set in the return value.
+ *
+ * Returns an enum event_trigger_type value containing a set bit for
+ * any trigger that should be deferred, ETT_NONE if nothing to defer.
+ *
+ * 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.
+ */
+enum event_trigger_type
+event_triggers_call(struct trace_event_file *file,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct event_trigger_data *data;
+ enum event_trigger_type tt = ETT_NONE;
+ struct event_filter *filter;
+
+ if (list_empty(&file->triggers))
+ return tt;
+
+ list_for_each_entry_rcu(data, &file->triggers, list) {
+ if (data->paused)
+ continue;
+ if (!rec) {
+ data->ops->trigger(data, buffer, rec, event);
+ continue;
+ }
+ filter = rcu_dereference_sched(data->filter);
+ if (filter && !filter_match_preds(filter, rec))
+ continue;
+ if (event_command_post_trigger(data->cmd_ops)) {
+ tt |= data->cmd_ops->trigger_type;
+ continue;
+ }
+ data->ops->trigger(data, buffer, rec, event);
+ }
+ return tt;
+}
+EXPORT_SYMBOL_GPL(event_triggers_call);
+
+bool __trace_trigger_soft_disabled(struct trace_event_file *file)
+{
+ unsigned long eflags = file->flags;
+
+ if (eflags & EVENT_FILE_FL_TRIGGER_MODE)
+ event_triggers_call(file, NULL, NULL, NULL);
+ if (eflags & EVENT_FILE_FL_SOFT_DISABLED)
+ return true;
+ if (eflags & EVENT_FILE_FL_PID_FILTER)
+ return trace_event_ignore_this_pid(file);
+ return false;
+}
+EXPORT_SYMBOL_GPL(__trace_trigger_soft_disabled);
+
+/**
+ * event_triggers_post_call - Call 'post_triggers' for a trace event
+ * @file: The trace_event_file associated with the event
+ * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
+ *
+ * For each trigger associated with an event, invoke the trigger
+ * function registered with the associated trigger command, if the
+ * corresponding bit is set in the tt enum passed into this function.
+ * See @event_triggers_call for details on how those bits are set.
+ *
+ * Called from tracepoint handlers (with rcu_read_lock_sched() held).
+ */
+void
+event_triggers_post_call(struct trace_event_file *file,
+ enum event_trigger_type tt)
+{
+ struct event_trigger_data *data;
+
+ list_for_each_entry_rcu(data, &file->triggers, list) {
+ if (data->paused)
+ continue;
+ if (data->cmd_ops->trigger_type & tt)
+ data->ops->trigger(data, NULL, NULL, NULL);
+ }
+}
+EXPORT_SYMBOL_GPL(event_triggers_post_call);
+
+#define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
+
+static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
+{
+ struct trace_event_file *event_file = event_file_data(m->private);
+
+ if (t == SHOW_AVAILABLE_TRIGGERS) {
+ (*pos)++;
+ return NULL;
+ }
+ return seq_list_next(t, &event_file->triggers, pos);
+}
+
+static bool check_user_trigger(struct trace_event_file *file)
+{
+ struct event_trigger_data *data;
+
+ list_for_each_entry_rcu(data, &file->triggers, list,
+ lockdep_is_held(&event_mutex)) {
+ if (data->flags & EVENT_TRIGGER_FL_PROBE)
+ continue;
+ return true;
+ }
+ return false;
+}
+
+static void *trigger_start(struct seq_file *m, loff_t *pos)
+{
+ struct trace_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);
+
+ if (list_empty(&event_file->triggers) || !check_user_trigger(event_file))
+ return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
+
+ 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;
+ struct event_command *p;
+
+ if (v == SHOW_AVAILABLE_TRIGGERS) {
+ seq_puts(m, "# Available triggers:\n");
+ seq_putc(m, '#');
+ mutex_lock(&trigger_cmd_mutex);
+ list_for_each_entry_reverse(p, &trigger_commands, list)
+ seq_printf(m, " %s", p->name);
+ seq_putc(m, '\n');
+ mutex_unlock(&trigger_cmd_mutex);
+ return 0;
+ }
+
+ data = list_entry(v, struct event_trigger_data, list);
+ data->ops->print(m, 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;
+
+ ret = security_locked_down(LOCKDOWN_TRACEFS);
+ if (ret)
+ return ret;
+
+ mutex_lock(&event_mutex);
+
+ if (unlikely(!event_file_data(file))) {
+ mutex_unlock(&event_mutex);
+ return -ENODEV;
+ }
+
+ if ((file->f_mode & FMODE_WRITE) &&
+ (file->f_flags & O_TRUNC)) {
+ struct trace_event_file *event_file;
+ struct event_command *p;
+
+ event_file = event_file_data(file);
+
+ list_for_each_entry(p, &trigger_commands, list) {
+ if (p->unreg_all)
+ p->unreg_all(event_file);
+ }
+ }
+
+ 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;
+}
+
+int trigger_process_regex(struct trace_event_file *file, char *buff)
+{
+ char *command, *next;
+ struct event_command *p;
+ int ret = -EINVAL;
+
+ next = buff = skip_spaces(buff);
+ command = strsep(&next, ": \t");
+ if (next) {
+ next = skip_spaces(next);
+ if (!*next)
+ next = NULL;
+ }
+ 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->parse(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 trace_event_file *event_file;
+ ssize_t ret;
+ char *buf;
+
+ if (!cnt)
+ return 0;
+
+ if (cnt >= PAGE_SIZE)
+ return -EINVAL;
+
+ buf = memdup_user_nul(ubuf, cnt);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ strim(buf);
+
+ mutex_lock(&event_mutex);
+ event_file = event_file_data(file);
+ if (unlikely(!event_file)) {
+ mutex_unlock(&event_mutex);
+ kfree(buf);
+ return -ENODEV;
+ }
+ ret = trigger_process_regex(event_file, buf);
+ mutex_unlock(&event_mutex);
+
+ kfree(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)
+{
+ /* Checks for tracefs lockdown */
+ 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 = tracing_lseek,
+ .release = event_trigger_release,
+};
+
+/*
+ * Currently we only register event commands from __init, so mark this
+ * __init too.
+ */
+__init int register_event_command(struct event_command *cmd)
+{
+ struct event_command *p;
+ int ret = 0;
+
+ mutex_lock(&trigger_cmd_mutex);
+ list_for_each_entry(p, &trigger_commands, list) {
+ if (strcmp(cmd->name, p->name) == 0) {
+ ret = -EBUSY;
+ goto out_unlock;
+ }
+ }
+ list_add(&cmd->list, &trigger_commands);
+ out_unlock:
+ mutex_unlock(&trigger_cmd_mutex);
+
+ return ret;
+}
+
+/*
+ * Currently we only unregister event commands from __init, so mark
+ * this __init too.
+ */
+__init int unregister_event_command(struct event_command *cmd)
+{
+ struct event_command *p, *n;
+ int ret = -ENODEV;
+
+ mutex_lock(&trigger_cmd_mutex);
+ list_for_each_entry_safe(p, n, &trigger_commands, list) {
+ if (strcmp(cmd->name, p->name) == 0) {
+ ret = 0;
+ list_del_init(&p->list);
+ goto out_unlock;
+ }
+ }
+ out_unlock:
+ mutex_unlock(&trigger_cmd_mutex);
+
+ return ret;
+}
+
+/**
+ * event_trigger_print - Generic event_trigger_ops @print implementation
+ * @name: The name of the event trigger
+ * @m: The seq_file being printed to
+ * @data: Trigger-specific data
+ * @filter_str: filter_str to print, if present
+ *
+ * Common implementation for event triggers to print themselves.
+ *
+ * Usually wrapped by a function that simply sets the @name of the
+ * trigger command and then invokes this.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+static int
+event_trigger_print(const char *name, struct seq_file *m,
+ void *data, char *filter_str)
+{
+ long count = (long)data;
+
+ seq_puts(m, name);
+
+ if (count == -1)
+ seq_puts(m, ":unlimited");
+ else
+ seq_printf(m, ":count=%ld", count);
+
+ if (filter_str)
+ seq_printf(m, " if %s\n", filter_str);
+ else
+ seq_putc(m, '\n');
+
+ return 0;
+}
+
+/**
+ * event_trigger_init - Generic event_trigger_ops @init implementation
+ * @data: Trigger-specific data
+ *
+ * Common implementation of event trigger initialization.
+ *
+ * Usually used directly as the @init method in event trigger
+ * implementations.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_init(struct event_trigger_data *data)
+{
+ data->ref++;
+ return 0;
+}
+
+/**
+ * event_trigger_free - Generic event_trigger_ops @free implementation
+ * @data: Trigger-specific data
+ *
+ * Common implementation of event trigger de-initialization.
+ *
+ * Usually used directly as the @free method in event trigger
+ * implementations.
+ */
+static void
+event_trigger_free(struct event_trigger_data *data)
+{
+ if (WARN_ON_ONCE(data->ref <= 0))
+ return;
+
+ data->ref--;
+ if (!data->ref)
+ trigger_data_free(data);
+}
+
+int trace_event_trigger_enable_disable(struct trace_event_file *file,
+ int trigger_enable)
+{
+ int ret = 0;
+
+ if (trigger_enable) {
+ if (atomic_inc_return(&file->tm_ref) > 1)
+ return ret;
+ set_bit(EVENT_FILE_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(EVENT_FILE_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 trace_event_file *file;
+
+ list_for_each_entry(file, &tr->events, list) {
+ struct event_trigger_data *data, *n;
+ list_for_each_entry_safe(data, n, &file->triggers, list) {
+ trace_event_trigger_enable_disable(file, 0);
+ list_del_rcu(&data->list);
+ if (data->ops->free)
+ data->ops->free(data);
+ }
+ }
+}
+
+/**
+ * update_cond_flag - Set or reset the TRIGGER_COND bit
+ * @file: The trace_event_file associated with the event
+ *
+ * If an event has triggers and any of those triggers has a filter or
+ * a post_trigger, trigger invocation needs to be deferred until after
+ * the current event has logged its data, and the event should have
+ * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
+ * cleared.
+ */
+void update_cond_flag(struct trace_event_file *file)
+{
+ struct event_trigger_data *data;
+ bool set_cond = false;
+
+ lockdep_assert_held(&event_mutex);
+
+ list_for_each_entry(data, &file->triggers, list) {
+ if (data->filter || event_command_post_trigger(data->cmd_ops) ||
+ event_command_needs_rec(data->cmd_ops)) {
+ set_cond = true;
+ break;
+ }
+ }
+
+ if (set_cond)
+ set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
+ else
+ clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
+}
+
+/**
+ * register_trigger - Generic event_command @reg implementation
+ * @glob: The raw string used to register the trigger
+ * @data: Trigger-specific data to associate with the trigger
+ * @file: The trace_event_file associated with the event
+ *
+ * Common implementation for event trigger registration.
+ *
+ * Usually used directly as the @reg method in event command
+ * implementations.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+static int register_trigger(char *glob,
+ struct event_trigger_data *data,
+ struct trace_event_file *file)
+{
+ struct event_trigger_data *test;
+ int ret = 0;
+
+ lockdep_assert_held(&event_mutex);
+
+ list_for_each_entry(test, &file->triggers, list) {
+ if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
+ ret = -EEXIST;
+ goto out;
+ }
+ }
+
+ if (data->ops->init) {
+ ret = data->ops->init(data);
+ if (ret < 0)
+ goto out;
+ }
+
+ list_add_rcu(&data->list, &file->triggers);
+
+ update_cond_flag(file);
+ ret = trace_event_trigger_enable_disable(file, 1);
+ if (ret < 0) {
+ list_del_rcu(&data->list);
+ update_cond_flag(file);
+ }
+out:
+ return ret;
+}
+
+/**
+ * unregister_trigger - Generic event_command @unreg implementation
+ * @glob: The raw string used to register the trigger
+ * @test: Trigger-specific data used to find the trigger to remove
+ * @file: The trace_event_file associated with the event
+ *
+ * Common implementation for event trigger unregistration.
+ *
+ * Usually used directly as the @unreg method in event command
+ * implementations.
+ */
+static void unregister_trigger(char *glob,
+ struct event_trigger_data *test,
+ struct trace_event_file *file)
+{
+ struct event_trigger_data *data = NULL, *iter;
+
+ lockdep_assert_held(&event_mutex);
+
+ list_for_each_entry(iter, &file->triggers, list) {
+ if (iter->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
+ data = iter;
+ list_del_rcu(&data->list);
+ trace_event_trigger_enable_disable(file, 0);
+ update_cond_flag(file);
+ break;
+ }
+ }
+
+ if (data && data->ops->free)
+ data->ops->free(data);
+}
+
+/*
+ * Event trigger parsing helper functions.
+ *
+ * These functions help make it easier to write an event trigger
+ * parsing function i.e. the struct event_command.parse() callback
+ * function responsible for parsing and registering a trigger command
+ * written to the 'trigger' file.
+ *
+ * A trigger command (or just 'trigger' for short) takes the form:
+ * [trigger] [if filter]
+ *
+ * The struct event_command.parse() callback (and other struct
+ * event_command functions) refer to several components of a trigger
+ * command. Those same components are referenced by the event trigger
+ * parsing helper functions defined below. These components are:
+ *
+ * cmd - the trigger command name
+ * glob - the trigger command name optionally prefaced with '!'
+ * param_and_filter - text following cmd and ':'
+ * param - text following cmd and ':' and stripped of filter
+ * filter - the optional filter text following (and including) 'if'
+ *
+ * To illustrate the use of these componenents, here are some concrete
+ * examples. For the following triggers:
+ *
+ * echo 'traceon:5 if pid == 0' > trigger
+ * - 'traceon' is both cmd and glob
+ * - '5 if pid == 0' is the param_and_filter
+ * - '5' is the param
+ * - 'if pid == 0' is the filter
+ *
+ * echo 'enable_event:sys:event:n' > trigger
+ * - 'enable_event' is both cmd and glob
+ * - 'sys:event:n' is the param_and_filter
+ * - 'sys:event:n' is the param
+ * - there is no filter
+ *
+ * echo 'hist:keys=pid if prio > 50' > trigger
+ * - 'hist' is both cmd and glob
+ * - 'keys=pid if prio > 50' is the param_and_filter
+ * - 'keys=pid' is the param
+ * - 'if prio > 50' is the filter
+ *
+ * echo '!enable_event:sys:event:n' > trigger
+ * - 'enable_event' the cmd
+ * - '!enable_event' is the glob
+ * - 'sys:event:n' is the param_and_filter
+ * - 'sys:event:n' is the param
+ * - there is no filter
+ *
+ * echo 'traceoff' > trigger
+ * - 'traceoff' is both cmd and glob
+ * - there is no param_and_filter
+ * - there is no param
+ * - there is no filter
+ *
+ * There are a few different categories of event trigger covered by
+ * these helpers:
+ *
+ * - triggers that don't require a parameter e.g. traceon
+ * - triggers that do require a parameter e.g. enable_event and hist
+ * - triggers that though they may not require a param may support an
+ * optional 'n' param (n = number of times the trigger should fire)
+ * e.g.: traceon:5 or enable_event:sys:event:n
+ * - triggers that do not support an 'n' param e.g. hist
+ *
+ * These functions can be used or ignored as necessary - it all
+ * depends on the complexity of the trigger, and the granularity of
+ * the functions supported reflects the fact that some implementations
+ * may need to customize certain aspects of their implementations and
+ * won't need certain functions. For instance, the hist trigger
+ * implementation doesn't use event_trigger_separate_filter() because
+ * it has special requirements for handling the filter.
+ */
+
+/**
+ * event_trigger_check_remove - check whether an event trigger specifies remove
+ * @glob: The trigger command string, with optional remove(!) operator
+ *
+ * The event trigger callback implementations pass in 'glob' as a
+ * parameter. This is the command name either with or without a
+ * remove(!) operator. This function simply parses the glob and
+ * determines whether the command corresponds to a trigger removal or
+ * a trigger addition.
+ *
+ * Return: true if this is a remove command, false otherwise
+ */
+bool event_trigger_check_remove(const char *glob)
+{
+ return (glob && glob[0] == '!') ? true : false;
+}
+
+/**
+ * event_trigger_empty_param - check whether the param is empty
+ * @param: The trigger param string
+ *
+ * The event trigger callback implementations pass in 'param' as a
+ * parameter. This corresponds to the string following the command
+ * name minus the command name. This function can be called by a
+ * callback implementation for any command that requires a param; a
+ * callback that doesn't require a param can ignore it.
+ *
+ * Return: true if this is an empty param, false otherwise
+ */
+bool event_trigger_empty_param(const char *param)
+{
+ return !param;
+}
+
+/**
+ * event_trigger_separate_filter - separate an event trigger from a filter
+ * @param_and_filter: String containing trigger and possibly filter
+ * @param: outparam, will be filled with a pointer to the trigger
+ * @filter: outparam, will be filled with a pointer to the filter
+ * @param_required: Specifies whether or not the param string is required
+ *
+ * Given a param string of the form '[trigger] [if filter]', this
+ * function separates the filter from the trigger and returns the
+ * trigger in @param and the filter in @filter. Either the @param
+ * or the @filter may be set to NULL by this function - if not set to
+ * NULL, they will contain strings corresponding to the trigger and
+ * filter.
+ *
+ * There are two cases that need to be handled with respect to the
+ * passed-in param: either the param is required, or it is not
+ * required. If @param_required is set, and there's no param, it will
+ * return -EINVAL. If @param_required is not set and there's a param
+ * that starts with a number, that corresponds to the case of a
+ * trigger with :n (n = number of times the trigger should fire) and
+ * the parsing continues normally; otherwise the function just returns
+ * and assumes param just contains a filter and there's nothing else
+ * to do.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_separate_filter(char *param_and_filter, char **param,
+ char **filter, bool param_required)
+{
+ int ret = 0;
+
+ *param = *filter = NULL;
+
+ if (!param_and_filter) {
+ if (param_required)
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Here we check for an optional param. The only legal
+ * optional param is :n, and if that's the case, continue
+ * below. Otherwise we assume what's left is a filter and
+ * return it as the filter string for the caller to deal with.
+ */
+ if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) {
+ *filter = param_and_filter;
+ goto out;
+ }
+
+ /*
+ * Separate the param from the filter (param [if filter]).
+ * Here we have either an optional :n param or a required
+ * param and an optional filter.
+ */
+ *param = strsep(&param_and_filter, " \t");
+
+ /*
+ * Here we have a filter, though it may be empty.
+ */
+ if (param_and_filter) {
+ *filter = skip_spaces(param_and_filter);
+ if (!**filter)
+ *filter = NULL;
+ }
+out:
+ return ret;
+}
+
+/**
+ * event_trigger_alloc - allocate and init event_trigger_data for a trigger
+ * @cmd_ops: The event_command operations for the trigger
+ * @cmd: The cmd string
+ * @param: The param string
+ * @private_data: User data to associate with the event trigger
+ *
+ * Allocate an event_trigger_data instance and initialize it. The
+ * @cmd_ops are used along with the @cmd and @param to get the
+ * trigger_ops to assign to the event_trigger_data. @private_data can
+ * also be passed in and associated with the event_trigger_data.
+ *
+ * Use event_trigger_free() to free an event_trigger_data object.
+ *
+ * Return: The trigger_data object success, NULL otherwise
+ */
+struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
+ char *cmd,
+ char *param,
+ void *private_data)
+{
+ struct event_trigger_data *trigger_data;
+ struct event_trigger_ops *trigger_ops;
+
+ trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
+
+ trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
+ if (!trigger_data)
+ return NULL;
+
+ trigger_data->count = -1;
+ trigger_data->ops = trigger_ops;
+ trigger_data->cmd_ops = cmd_ops;
+ trigger_data->private_data = private_data;
+
+ INIT_LIST_HEAD(&trigger_data->list);
+ INIT_LIST_HEAD(&trigger_data->named_list);
+ RCU_INIT_POINTER(trigger_data->filter, NULL);
+
+ return trigger_data;
+}
+
+/**
+ * event_trigger_parse_num - parse and return the number param for a trigger
+ * @param: The param string
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Parse the :n (n = number of times the trigger should fire) param
+ * and set the count variable in the trigger_data to the parsed count.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_parse_num(char *param,
+ struct event_trigger_data *trigger_data)
+{
+ char *number;
+ int ret = 0;
+
+ if (param) {
+ number = strsep(&param, ":");
+
+ if (!strlen(number))
+ return -EINVAL;
+
+ /*
+ * We use the callback data field (which is a pointer)
+ * as our counter.
+ */
+ ret = kstrtoul(number, 0, &trigger_data->count);
+ }
+
+ return ret;
+}
+
+/**
+ * event_trigger_set_filter - set an event trigger's filter
+ * @cmd_ops: The event_command operations for the trigger
+ * @file: The event file for the trigger's event
+ * @param: The string containing the filter
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Set the filter for the trigger. If the filter is NULL, just return
+ * without error.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_set_filter(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *param,
+ struct event_trigger_data *trigger_data)
+{
+ if (param && cmd_ops->set_filter)
+ return cmd_ops->set_filter(param, trigger_data, file);
+
+ return 0;
+}
+
+/**
+ * event_trigger_reset_filter - reset an event trigger's filter
+ * @cmd_ops: The event_command operations for the trigger
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Reset the filter for the trigger to no filter.
+ */
+void event_trigger_reset_filter(struct event_command *cmd_ops,
+ struct event_trigger_data *trigger_data)
+{
+ if (cmd_ops->set_filter)
+ cmd_ops->set_filter(NULL, trigger_data, NULL);
+}
+
+/**
+ * event_trigger_register - register an event trigger
+ * @cmd_ops: The event_command operations for the trigger
+ * @file: The event file for the trigger's event
+ * @glob: The trigger command string, with optional remove(!) operator
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Register an event trigger. The @cmd_ops are used to call the
+ * cmd_ops->reg() function which actually does the registration.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_register(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob,
+ struct event_trigger_data *trigger_data)
+{
+ return cmd_ops->reg(glob, trigger_data, file);
+}
+
+/**
+ * event_trigger_unregister - unregister an event trigger
+ * @cmd_ops: The event_command operations for the trigger
+ * @file: The event file for the trigger's event
+ * @glob: The trigger command string, with optional remove(!) operator
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Unregister an event trigger. The @cmd_ops are used to call the
+ * cmd_ops->unreg() function which actually does the unregistration.
+ */
+void event_trigger_unregister(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob,
+ struct event_trigger_data *trigger_data)
+{
+ cmd_ops->unreg(glob, trigger_data, file);
+}
+
+/*
+ * End event trigger parsing helper functions.
+ */
+
+/**
+ * event_trigger_parse - Generic event_command @parse implementation
+ * @cmd_ops: The command ops, used for trigger registration
+ * @file: The trace_event_file associated with the event
+ * @glob: The raw string used to register the trigger
+ * @cmd: The cmd portion of the string used to register the trigger
+ * @param_and_filter: The param and filter portion of the string used to register the trigger
+ *
+ * Common implementation for event command parsing and trigger
+ * instantiation.
+ *
+ * Usually used directly as the @parse method in event command
+ * implementations.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+static int
+event_trigger_parse(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param_and_filter)
+{
+ struct event_trigger_data *trigger_data;
+ char *param, *filter;
+ bool remove;
+ int ret;
+
+ remove = event_trigger_check_remove(glob);
+
+ ret = event_trigger_separate_filter(param_and_filter, &param, &filter, false);
+ if (ret)
+ return ret;
+
+ ret = -ENOMEM;
+ trigger_data = event_trigger_alloc(cmd_ops, cmd, param, file);
+ if (!trigger_data)
+ goto out;
+
+ if (remove) {
+ event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
+ kfree(trigger_data);
+ ret = 0;
+ goto out;
+ }
+
+ ret = event_trigger_parse_num(param, trigger_data);
+ if (ret)
+ goto out_free;
+
+ ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
+ if (ret < 0)
+ goto out_free;
+
+ /* Up the trigger_data count to make sure reg doesn't free it on failure */
+ event_trigger_init(trigger_data);
+
+ ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
+ if (ret)
+ goto out_free;
+
+ /* Down the counter of trigger_data or free it if not used anymore */
+ event_trigger_free(trigger_data);
+ out:
+ return ret;
+
+ out_free:
+ event_trigger_reset_filter(cmd_ops, trigger_data);
+ kfree(trigger_data);
+ goto out;
+}
+
+/**
+ * set_trigger_filter - Generic event_command @set_filter implementation
+ * @filter_str: The filter string for the trigger, NULL to remove filter
+ * @trigger_data: Trigger-specific data
+ * @file: The trace_event_file associated with the event
+ *
+ * Common implementation for event command filter parsing and filter
+ * instantiation.
+ *
+ * Usually used directly as the @set_filter method in event command
+ * implementations.
+ *
+ * Also used to remove a filter (if filter_str = NULL).
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int set_trigger_filter(char *filter_str,
+ struct event_trigger_data *trigger_data,
+ struct trace_event_file *file)
+{
+ struct event_trigger_data *data = trigger_data;
+ struct event_filter *filter = NULL, *tmp;
+ int ret = -EINVAL;
+ char *s;
+
+ if (!filter_str) /* clear the current filter */
+ goto assign;
+
+ s = strsep(&filter_str, " \t");
+
+ if (!strlen(s) || strcmp(s, "if") != 0)
+ goto out;
+
+ if (!filter_str)
+ goto out;
+
+ /* The filter is for the 'trigger' event, not the triggered event */
+ ret = create_event_filter(file->tr, file->event_call,
+ filter_str, true, &filter);
+
+ /* Only enabled set_str for error handling */
+ if (filter) {
+ kfree(filter->filter_string);
+ filter->filter_string = NULL;
+ }
+
+ /*
+ * If create_event_filter() fails, filter still needs to be freed.
+ * Which the calling code will do with data->filter.
+ */
+ assign:
+ tmp = rcu_access_pointer(data->filter);
+
+ rcu_assign_pointer(data->filter, filter);
+
+ if (tmp) {
+ /*
+ * Make sure the call is done with the filter.
+ * It is possible that a filter could fail at boot up,
+ * and then this path will be called. Avoid the synchronization
+ * in that case.
+ */
+ if (system_state != SYSTEM_BOOTING)
+ tracepoint_synchronize_unregister();
+ free_event_filter(tmp);
+ }
+
+ kfree(data->filter_str);
+ data->filter_str = NULL;
+
+ if (filter_str) {
+ data->filter_str = kstrdup(filter_str, GFP_KERNEL);
+ if (!data->filter_str) {
+ free_event_filter(rcu_access_pointer(data->filter));
+ data->filter = NULL;
+ ret = -ENOMEM;
+ }
+ }
+ out:
+ return ret;
+}
+
+static LIST_HEAD(named_triggers);
+
+/**
+ * find_named_trigger - Find the common named trigger associated with @name
+ * @name: The name of the set of named triggers to find the common data for
+ *
+ * Named triggers are sets of triggers that share a common set of
+ * trigger data. The first named trigger registered with a given name
+ * owns the common trigger data that the others subsequently
+ * registered with the same name will reference. This function
+ * returns the common trigger data associated with that first
+ * registered instance.
+ *
+ * Return: the common trigger data for the given named trigger on
+ * success, NULL otherwise.
+ */
+struct event_trigger_data *find_named_trigger(const char *name)
+{
+ struct event_trigger_data *data;
+
+ if (!name)
+ return NULL;
+
+ list_for_each_entry(data, &named_triggers, named_list) {
+ if (data->named_data)
+ continue;
+ if (strcmp(data->name, name) == 0)
+ return data;
+ }
+
+ return NULL;
+}
+
+/**
+ * is_named_trigger - determine if a given trigger is a named trigger
+ * @test: The trigger data to test
+ *
+ * Return: true if 'test' is a named trigger, false otherwise.
+ */
+bool is_named_trigger(struct event_trigger_data *test)
+{
+ struct event_trigger_data *data;
+
+ list_for_each_entry(data, &named_triggers, named_list) {
+ if (test == data)
+ return true;
+ }
+
+ return false;
+}
+
+/**
+ * save_named_trigger - save the trigger in the named trigger list
+ * @name: The name of the named trigger set
+ * @data: The trigger data to save
+ *
+ * Return: 0 if successful, negative error otherwise.
+ */
+int save_named_trigger(const char *name, struct event_trigger_data *data)
+{
+ data->name = kstrdup(name, GFP_KERNEL);
+ if (!data->name)
+ return -ENOMEM;
+
+ list_add(&data->named_list, &named_triggers);
+
+ return 0;
+}
+
+/**
+ * del_named_trigger - delete a trigger from the named trigger list
+ * @data: The trigger data to delete
+ */
+void del_named_trigger(struct event_trigger_data *data)
+{
+ kfree(data->name);
+ data->name = NULL;
+
+ list_del(&data->named_list);
+}
+
+static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
+{
+ struct event_trigger_data *test;
+
+ list_for_each_entry(test, &named_triggers, named_list) {
+ if (strcmp(test->name, data->name) == 0) {
+ if (pause) {
+ test->paused_tmp = test->paused;
+ test->paused = true;
+ } else {
+ test->paused = test->paused_tmp;
+ }
+ }
+ }
+}
+
+/**
+ * pause_named_trigger - Pause all named triggers with the same name
+ * @data: The trigger data of a named trigger to pause
+ *
+ * Pauses a named trigger along with all other triggers having the
+ * same name. Because named triggers share a common set of data,
+ * pausing only one is meaningless, so pausing one named trigger needs
+ * to pause all triggers with the same name.
+ */
+void pause_named_trigger(struct event_trigger_data *data)
+{
+ __pause_named_trigger(data, true);
+}
+
+/**
+ * unpause_named_trigger - Un-pause all named triggers with the same name
+ * @data: The trigger data of a named trigger to unpause
+ *
+ * Un-pauses a named trigger along with all other triggers having the
+ * same name. Because named triggers share a common set of data,
+ * unpausing only one is meaningless, so unpausing one named trigger
+ * needs to unpause all triggers with the same name.
+ */
+void unpause_named_trigger(struct event_trigger_data *data)
+{
+ __pause_named_trigger(data, false);
+}
+
+/**
+ * set_named_trigger_data - Associate common named trigger data
+ * @data: The trigger data to associate
+ * @named_data: The common named trigger to be associated
+ *
+ * Named triggers are sets of triggers that share a common set of
+ * trigger data. The first named trigger registered with a given name
+ * owns the common trigger data that the others subsequently
+ * registered with the same name will reference. This function
+ * associates the common trigger data from the first trigger with the
+ * given trigger.
+ */
+void set_named_trigger_data(struct event_trigger_data *data,
+ struct event_trigger_data *named_data)
+{
+ data->named_data = named_data;
+}
+
+struct event_trigger_data *
+get_named_trigger_data(struct event_trigger_data *data)
+{
+ return data->named_data;
+}
+
+static void
+traceon_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct trace_event_file *file = data->private_data;
+
+ if (file) {
+ if (tracer_tracing_is_on(file->tr))
+ return;
+
+ tracer_tracing_on(file->tr);
+ return;
+ }
+
+ if (tracing_is_on())
+ return;
+
+ tracing_on();
+}
+
+static void
+traceon_count_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct trace_event_file *file = data->private_data;
+
+ if (file) {
+ if (tracer_tracing_is_on(file->tr))
+ return;
+ } else {
+ if (tracing_is_on())
+ return;
+ }
+
+ if (!data->count)
+ return;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ if (file)
+ tracer_tracing_on(file->tr);
+ else
+ tracing_on();
+}
+
+static void
+traceoff_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct trace_event_file *file = data->private_data;
+
+ if (file) {
+ if (!tracer_tracing_is_on(file->tr))
+ return;
+
+ tracer_tracing_off(file->tr);
+ return;
+ }
+
+ if (!tracing_is_on())
+ return;
+
+ tracing_off();
+}
+
+static void
+traceoff_count_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct trace_event_file *file = data->private_data;
+
+ if (file) {
+ if (!tracer_tracing_is_on(file->tr))
+ return;
+ } else {
+ if (!tracing_is_on())
+ return;
+ }
+
+ if (!data->count)
+ return;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ if (file)
+ tracer_tracing_off(file->tr);
+ else
+ tracing_off();
+}
+
+static int
+traceon_trigger_print(struct seq_file *m, struct event_trigger_data *data)
+{
+ return event_trigger_print("traceon", m, (void *)data->count,
+ data->filter_str);
+}
+
+static int
+traceoff_trigger_print(struct seq_file *m, struct event_trigger_data *data)
+{
+ return event_trigger_print("traceoff", m, (void *)data->count,
+ data->filter_str);
+}
+
+static struct event_trigger_ops traceon_trigger_ops = {
+ .trigger = traceon_trigger,
+ .print = traceon_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops traceon_count_trigger_ops = {
+ .trigger = traceon_count_trigger,
+ .print = traceon_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops traceoff_trigger_ops = {
+ .trigger = traceoff_trigger,
+ .print = traceoff_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops traceoff_count_trigger_ops = {
+ .trigger = traceoff_count_trigger,
+ .print = traceoff_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops *
+onoff_get_trigger_ops(char *cmd, char *param)
+{
+ struct event_trigger_ops *ops;
+
+ /* we register both traceon and traceoff to this callback */
+ if (strcmp(cmd, "traceon") == 0)
+ ops = param ? &traceon_count_trigger_ops :
+ &traceon_trigger_ops;
+ else
+ ops = param ? &traceoff_count_trigger_ops :
+ &traceoff_trigger_ops;
+
+ return ops;
+}
+
+static struct event_command trigger_traceon_cmd = {
+ .name = "traceon",
+ .trigger_type = ETT_TRACE_ONOFF,
+ .parse = event_trigger_parse,
+ .reg = register_trigger,
+ .unreg = unregister_trigger,
+ .get_trigger_ops = onoff_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+static struct event_command trigger_traceoff_cmd = {
+ .name = "traceoff",
+ .trigger_type = ETT_TRACE_ONOFF,
+ .flags = EVENT_CMD_FL_POST_TRIGGER,
+ .parse = event_trigger_parse,
+ .reg = register_trigger,
+ .unreg = unregister_trigger,
+ .get_trigger_ops = onoff_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+static void
+snapshot_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct trace_event_file *file = data->private_data;
+
+ if (file)
+ tracing_snapshot_instance(file->tr);
+ else
+ tracing_snapshot();
+}
+
+static void
+snapshot_count_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ if (!data->count)
+ return;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ snapshot_trigger(data, buffer, rec, event);
+}
+
+static int
+register_snapshot_trigger(char *glob,
+ struct event_trigger_data *data,
+ struct trace_event_file *file)
+{
+ if (tracing_alloc_snapshot_instance(file->tr) != 0)
+ return 0;
+
+ return register_trigger(glob, data, file);
+}
+
+static int
+snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data)
+{
+ return event_trigger_print("snapshot", m, (void *)data->count,
+ data->filter_str);
+}
+
+static struct event_trigger_ops snapshot_trigger_ops = {
+ .trigger = snapshot_trigger,
+ .print = snapshot_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops snapshot_count_trigger_ops = {
+ .trigger = snapshot_count_trigger,
+ .print = snapshot_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops *
+snapshot_get_trigger_ops(char *cmd, char *param)
+{
+ return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
+}
+
+static struct event_command trigger_snapshot_cmd = {
+ .name = "snapshot",
+ .trigger_type = ETT_SNAPSHOT,
+ .parse = event_trigger_parse,
+ .reg = register_snapshot_trigger,
+ .unreg = unregister_trigger,
+ .get_trigger_ops = snapshot_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+static __init int register_trigger_snapshot_cmd(void)
+{
+ int ret;
+
+ ret = register_event_command(&trigger_snapshot_cmd);
+ WARN_ON(ret < 0);
+
+ return ret;
+}
+#else
+static __init int register_trigger_snapshot_cmd(void) { return 0; }
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+#ifdef CONFIG_STACKTRACE
+#ifdef CONFIG_UNWINDER_ORC
+/* Skip 2:
+ * event_triggers_post_call()
+ * trace_event_raw_event_xxx()
+ */
+# define STACK_SKIP 2
+#else
+/*
+ * Skip 4:
+ * stacktrace_trigger()
+ * event_triggers_post_call()
+ * trace_event_buffer_commit()
+ * trace_event_raw_event_xxx()
+ */
+#define STACK_SKIP 4
+#endif
+
+static void
+stacktrace_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct trace_event_file *file = data->private_data;
+
+ if (file)
+ __trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP);
+ else
+ trace_dump_stack(STACK_SKIP);
+}
+
+static void
+stacktrace_count_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ if (!data->count)
+ return;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ stacktrace_trigger(data, buffer, rec, event);
+}
+
+static int
+stacktrace_trigger_print(struct seq_file *m, struct event_trigger_data *data)
+{
+ return event_trigger_print("stacktrace", m, (void *)data->count,
+ data->filter_str);
+}
+
+static struct event_trigger_ops stacktrace_trigger_ops = {
+ .trigger = stacktrace_trigger,
+ .print = stacktrace_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops stacktrace_count_trigger_ops = {
+ .trigger = stacktrace_count_trigger,
+ .print = stacktrace_trigger_print,
+ .init = event_trigger_init,
+ .free = event_trigger_free,
+};
+
+static struct event_trigger_ops *
+stacktrace_get_trigger_ops(char *cmd, char *param)
+{
+ return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
+}
+
+static struct event_command trigger_stacktrace_cmd = {
+ .name = "stacktrace",
+ .trigger_type = ETT_STACKTRACE,
+ .flags = EVENT_CMD_FL_POST_TRIGGER,
+ .parse = event_trigger_parse,
+ .reg = register_trigger,
+ .unreg = unregister_trigger,
+ .get_trigger_ops = stacktrace_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+static __init int register_trigger_stacktrace_cmd(void)
+{
+ int ret;
+
+ ret = register_event_command(&trigger_stacktrace_cmd);
+ WARN_ON(ret < 0);
+
+ return ret;
+}
+#else
+static __init int register_trigger_stacktrace_cmd(void) { return 0; }
+#endif /* CONFIG_STACKTRACE */
+
+static __init void unregister_trigger_traceon_traceoff_cmds(void)
+{
+ unregister_event_command(&trigger_traceon_cmd);
+ unregister_event_command(&trigger_traceoff_cmd);
+}
+
+static void
+event_enable_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct enable_trigger_data *enable_data = data->private_data;
+
+ if (enable_data->enable)
+ clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
+ else
+ set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
+}
+
+static void
+event_enable_count_trigger(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *event)
+{
+ struct enable_trigger_data *enable_data = data->private_data;
+
+ if (!data->count)
+ return;
+
+ /* Skip if the event is in a state we want to switch to */
+ if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
+ return;
+
+ if (data->count != -1)
+ (data->count)--;
+
+ event_enable_trigger(data, buffer, rec, event);
+}
+
+int event_enable_trigger_print(struct seq_file *m,
+ struct event_trigger_data *data)
+{
+ struct enable_trigger_data *enable_data = data->private_data;
+
+ seq_printf(m, "%s:%s:%s",
+ enable_data->hist ?
+ (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
+ (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
+ enable_data->file->event_call->class->system,
+ trace_event_name(enable_data->file->event_call));
+
+ if (data->count == -1)
+ seq_puts(m, ":unlimited");
+ else
+ seq_printf(m, ":count=%ld", data->count);
+
+ if (data->filter_str)
+ seq_printf(m, " if %s\n", data->filter_str);
+ else
+ seq_putc(m, '\n');
+
+ return 0;
+}
+
+void event_enable_trigger_free(struct event_trigger_data *data)
+{
+ struct enable_trigger_data *enable_data = data->private_data;
+
+ if (WARN_ON_ONCE(data->ref <= 0))
+ return;
+
+ data->ref--;
+ if (!data->ref) {
+ /* Remove the SOFT_MODE flag */
+ trace_event_enable_disable(enable_data->file, 0, 1);
+ trace_event_put_ref(enable_data->file->event_call);
+ trigger_data_free(data);
+ kfree(enable_data);
+ }
+}
+
+static struct event_trigger_ops event_enable_trigger_ops = {
+ .trigger = event_enable_trigger,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
+};
+
+static struct event_trigger_ops event_enable_count_trigger_ops = {
+ .trigger = event_enable_count_trigger,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
+};
+
+static struct event_trigger_ops event_disable_trigger_ops = {
+ .trigger = event_enable_trigger,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
+};
+
+static struct event_trigger_ops event_disable_count_trigger_ops = {
+ .trigger = event_enable_count_trigger,
+ .print = event_enable_trigger_print,
+ .init = event_trigger_init,
+ .free = event_enable_trigger_free,
+};
+
+int event_enable_trigger_parse(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param_and_filter)
+{
+ struct trace_event_file *event_enable_file;
+ struct enable_trigger_data *enable_data;
+ struct event_trigger_data *trigger_data;
+ struct trace_array *tr = file->tr;
+ char *param, *filter;
+ bool enable, remove;
+ const char *system;
+ const char *event;
+ bool hist = false;
+ int ret;
+
+ remove = event_trigger_check_remove(glob);
+
+ if (event_trigger_empty_param(param_and_filter))
+ return -EINVAL;
+
+ ret = event_trigger_separate_filter(param_and_filter, &param, &filter, true);
+ if (ret)
+ return ret;
+
+ system = strsep(&param, ":");
+ if (!param)
+ return -EINVAL;
+
+ event = strsep(&param, ":");
+
+ ret = -EINVAL;
+ event_enable_file = find_event_file(tr, system, event);
+ if (!event_enable_file)
+ goto out;
+
+#ifdef CONFIG_HIST_TRIGGERS
+ hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
+ (strcmp(cmd, DISABLE_HIST_STR) == 0));
+
+ enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
+ (strcmp(cmd, ENABLE_HIST_STR) == 0));
+#else
+ enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
+#endif
+ ret = -ENOMEM;
+
+ enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
+ if (!enable_data)
+ goto out;
+
+ enable_data->hist = hist;
+ enable_data->enable = enable;
+ enable_data->file = event_enable_file;
+
+ trigger_data = event_trigger_alloc(cmd_ops, cmd, param, enable_data);
+ if (!trigger_data) {
+ kfree(enable_data);
+ goto out;
+ }
+
+ if (remove) {
+ event_trigger_unregister(cmd_ops, file, glob+1, trigger_data);
+ kfree(trigger_data);
+ kfree(enable_data);
+ ret = 0;
+ goto out;
+ }
+
+ /* Up the trigger_data count to make sure nothing frees it on failure */
+ event_trigger_init(trigger_data);
+
+ ret = event_trigger_parse_num(param, trigger_data);
+ if (ret)
+ goto out_free;
+
+ ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
+ if (ret < 0)
+ goto out_free;
+
+ /* Don't let event modules unload while probe registered */
+ ret = trace_event_try_get_ref(event_enable_file->event_call);
+ if (!ret) {
+ ret = -EBUSY;
+ goto out_free;
+ }
+
+ ret = trace_event_enable_disable(event_enable_file, 1, 1);
+ if (ret < 0)
+ goto out_put;
+
+ ret = event_trigger_register(cmd_ops, file, glob, trigger_data);
+ if (ret)
+ goto out_disable;
+
+ event_trigger_free(trigger_data);
+ out:
+ return ret;
+ out_disable:
+ trace_event_enable_disable(event_enable_file, 0, 1);
+ out_put:
+ trace_event_put_ref(event_enable_file->event_call);
+ out_free:
+ event_trigger_reset_filter(cmd_ops, trigger_data);
+ event_trigger_free(trigger_data);
+ kfree(enable_data);
+
+ goto out;
+}
+
+int event_enable_register_trigger(char *glob,
+ struct event_trigger_data *data,
+ struct trace_event_file *file)
+{
+ struct enable_trigger_data *enable_data = data->private_data;
+ struct enable_trigger_data *test_enable_data;
+ struct event_trigger_data *test;
+ int ret = 0;
+
+ lockdep_assert_held(&event_mutex);
+
+ list_for_each_entry(test, &file->triggers, list) {
+ test_enable_data = test->private_data;
+ if (test_enable_data &&
+ (test->cmd_ops->trigger_type ==
+ data->cmd_ops->trigger_type) &&
+ (test_enable_data->file == enable_data->file)) {
+ ret = -EEXIST;
+ goto out;
+ }
+ }
+
+ if (data->ops->init) {
+ ret = data->ops->init(data);
+ if (ret < 0)
+ goto out;
+ }
+
+ list_add_rcu(&data->list, &file->triggers);
+
+ update_cond_flag(file);
+ ret = trace_event_trigger_enable_disable(file, 1);
+ if (ret < 0) {
+ list_del_rcu(&data->list);
+ update_cond_flag(file);
+ }
+out:
+ return ret;
+}
+
+void event_enable_unregister_trigger(char *glob,
+ struct event_trigger_data *test,
+ struct trace_event_file *file)
+{
+ struct enable_trigger_data *test_enable_data = test->private_data;
+ struct event_trigger_data *data = NULL, *iter;
+ struct enable_trigger_data *enable_data;
+
+ lockdep_assert_held(&event_mutex);
+
+ list_for_each_entry(iter, &file->triggers, list) {
+ enable_data = iter->private_data;
+ if (enable_data &&
+ (iter->cmd_ops->trigger_type ==
+ test->cmd_ops->trigger_type) &&
+ (enable_data->file == test_enable_data->file)) {
+ data = iter;
+ list_del_rcu(&data->list);
+ trace_event_trigger_enable_disable(file, 0);
+ update_cond_flag(file);
+ break;
+ }
+ }
+
+ if (data && data->ops->free)
+ data->ops->free(data);
+}
+
+static struct event_trigger_ops *
+event_enable_get_trigger_ops(char *cmd, char *param)
+{
+ struct event_trigger_ops *ops;
+ bool enable;
+
+#ifdef CONFIG_HIST_TRIGGERS
+ enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
+ (strcmp(cmd, ENABLE_HIST_STR) == 0));
+#else
+ enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
+#endif
+ if (enable)
+ ops = param ? &event_enable_count_trigger_ops :
+ &event_enable_trigger_ops;
+ else
+ ops = param ? &event_disable_count_trigger_ops :
+ &event_disable_trigger_ops;
+
+ return ops;
+}
+
+static struct event_command trigger_enable_cmd = {
+ .name = ENABLE_EVENT_STR,
+ .trigger_type = ETT_EVENT_ENABLE,
+ .parse = event_enable_trigger_parse,
+ .reg = event_enable_register_trigger,
+ .unreg = event_enable_unregister_trigger,
+ .get_trigger_ops = event_enable_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+static struct event_command trigger_disable_cmd = {
+ .name = DISABLE_EVENT_STR,
+ .trigger_type = ETT_EVENT_ENABLE,
+ .parse = event_enable_trigger_parse,
+ .reg = event_enable_register_trigger,
+ .unreg = event_enable_unregister_trigger,
+ .get_trigger_ops = event_enable_get_trigger_ops,
+ .set_filter = set_trigger_filter,
+};
+
+static __init void unregister_trigger_enable_disable_cmds(void)
+{
+ unregister_event_command(&trigger_enable_cmd);
+ unregister_event_command(&trigger_disable_cmd);
+}
+
+static __init int register_trigger_enable_disable_cmds(void)
+{
+ int ret;
+
+ ret = register_event_command(&trigger_enable_cmd);
+ if (WARN_ON(ret < 0))
+ return ret;
+ ret = register_event_command(&trigger_disable_cmd);
+ if (WARN_ON(ret < 0))
+ unregister_trigger_enable_disable_cmds();
+
+ return ret;
+}
+
+static __init int register_trigger_traceon_traceoff_cmds(void)
+{
+ int ret;
+
+ ret = register_event_command(&trigger_traceon_cmd);
+ if (WARN_ON(ret < 0))
+ return ret;
+ ret = register_event_command(&trigger_traceoff_cmd);
+ if (WARN_ON(ret < 0))
+ unregister_trigger_traceon_traceoff_cmds();
+
+ return ret;
+}
+
+__init int register_trigger_cmds(void)
+{
+ register_trigger_traceon_traceoff_cmds();
+ register_trigger_snapshot_cmd();
+ register_trigger_stacktrace_cmd();
+ register_trigger_enable_disable_cmds();
+ register_trigger_hist_enable_disable_cmds();
+ register_trigger_hist_cmd();
+
+ return 0;
+}