[PATCH 23/32] tracing: Add 'onmatch' hist trigger action support

Tom Zanussi
2017-06-26T22:52:42Z

Add an 'onmatch(matching.event).<synthetic_event_name>(param list)'
hist trigger action which is invoked with the set of variables or
event fields named in the 'param list'. The result is the generation
of a synthetic event that consists of the values contained in those
variables and/or fields at the time the invoking event was hit.

As an example the below defines a simple synthetic event using a
variable defined on the sched_wakeup_new event, and shows the event
definition with unresolved fields, since the sched_wakeup_new event
with the testpid variable hasn't been defined yet:

# echo 'wakeup_new_test pid_t pid; int prio' >> \
/sys/kernel/debug/tracing/synthetic_events

# cat /sys/kernel/debug/tracing/synthetic_events
wakeup_new_test pid_t pid; int prio

The following hist trigger both defines a testpid variable and
specifies an onmatch() trace action that uses that variable along with
a non-variable field to generate a wakeup_new_test synthetic event
whenever a sched_wakeup_new event occurs, which because of the 'if
comm == "cyclictest"' filter only happens when the executable is
cyclictest:

# echo 'hist:keys=testpid=pid:\
onmatch(sched.sched_wakeup_new).wakeup_new_test($testpid, prio) \
if comm=="cyclictest"' >> \
/sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger

Creating and displaying a histogram based on those events is now just
a matter of using the fields and new synthetic event in the
tracing/events/synthetic directory, as usual:

# echo 'hist:keys=pid,prio:sort=pid,prio' >> \
/sys/kernel/debug/tracing/events/synthetic/wakeup_new_test/trigger

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
kernel/trace/trace_events_hist.c | 955 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 940 insertions(+), 15 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index e11b3a3..b1f859c 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -59,6 +59,7 @@ struct hist_field {
unsigned int size;
unsigned int offset;
unsigned int is_signed;
+ const char *type;
struct hist_field *operands[HIST_FIELD_OPERANDS_MAX];
struct hist_trigger_data *hist_data;
struct hist_var var;
@@ -243,6 +244,16 @@ struct hist_trigger_attrs {
unsigned int n_actions;
};

+struct field_var {
+ struct hist_field *var;
+ struct hist_field *val;
+};
+
+struct field_var_hist {
+ struct hist_trigger_data *hist_data;
+ char *cmd;
+};
+
struct hist_trigger_data {
struct hist_field *fields[HIST_FIELDS_MAX];
unsigned int n_vals;
@@ -263,6 +274,14 @@ struct hist_trigger_data {

struct action_data *actions[HIST_ACTIONS_MAX];
unsigned int n_actions;
+
+ struct hist_field *synth_var_refs[SYNTH_FIELDS_MAX];
+ unsigned int n_synth_var_refs;
+ struct field_var *field_vars[SYNTH_FIELDS_MAX];
+ unsigned int n_field_vars;
+ unsigned int n_field_var_str;
+ struct field_var_hist *field_var_hists[SYNTH_FIELDS_MAX];
+ unsigned int n_field_var_hists;
};

struct synth_field {
@@ -291,7 +310,14 @@ typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,

struct action_data {
action_fn_t fn;
+ unsigned int n_params;
+ char *params[SYNTH_FIELDS_MAX];
+
unsigned int var_ref_idx;
+ char *match_event;
+ char *match_event_system;
+ char *synth_event_name;
+ struct synth_event *synth_event;
};

static LIST_HEAD(synth_event_list);
@@ -802,6 +828,50 @@ static struct synth_event *alloc_synth_event(char *event_name, int n_fields,
return event;
}

+static void action_trace(struct hist_trigger_data *hist_data,
+ struct tracing_map_elt *elt, void *rec,
+ struct ring_buffer_event *rbe,
+ struct action_data *data, u64 *var_ref_vals)
+{
+ struct synth_event *event = data->synth_event;
+
+ trace_synth(event, var_ref_vals, data->var_ref_idx);
+}
+
+static bool check_hist_action_refs(struct hist_trigger_data *hist_data,
+ struct synth_event *event)
+{
+ unsigned int i;
+
+ for (i = 0; i < hist_data->n_actions; i++) {
+ struct action_data *data = hist_data->actions[i];
+
+ if (data->fn == action_trace && data->synth_event == event)
+ return true;
+ }
+
+ return false;
+}
+
+static LIST_HEAD(hist_action_list);
+static LIST_HEAD(hist_var_list);
+
+struct hist_var_data {
+ struct list_head list;
+ struct hist_trigger_data *hist_data;
+};
+
+static bool check_synth_action_refs(struct synth_event *event)
+{
+ struct hist_var_data *var_data;
+
+ list_for_each_entry(var_data, &hist_action_list, list)
+ if (check_hist_action_refs(var_data->hist_data, event))
+ return true;
+
+ return false;
+}
+
static int create_synth_event(int argc, char **argv)
{
struct synth_field *fields[SYNTH_FIELDS_MAX];
@@ -832,15 +902,17 @@ static int create_synth_event(int argc, char **argv)
event = find_synth_event(name);
if (event) {
if (delete_event) {
+ if (check_synth_action_refs(event)) {
+ ret = -EBUSY;
+ goto out;
+ }
remove_synth_event(event);
goto err;
} else
ret = -EEXIST;
goto out;
- } else if (delete_event) {
- ret = -EINVAL;
+ } else if (delete_event)
goto out;
- }

if (argc < 2) {
ret = -EINVAL;
@@ -891,11 +963,18 @@ static int release_all_synth_events(void)

mutex_lock(&synth_event_mutex);

+ list_for_each_entry(event, &synth_event_list, list) {
+ if (check_synth_action_refs(event)) {
+ ret = -EBUSY;
+ goto out;
+ }
+ }
+
list_for_each_entry_safe(event, e, &synth_event_list, list) {
remove_synth_event(event);
free_synth_event(event);
}
-
+ out:
mutex_unlock(&synth_event_mutex);

return ret;
@@ -992,13 +1071,6 @@ static u64 hist_field_timestamp(struct hist_field *hist_field,
return ts;
}

-static LIST_HEAD(hist_var_list);
-
-struct hist_var_data {
- struct list_head list;
- struct hist_trigger_data *hist_data;
-};
-
static struct hist_field *check_var_ref(struct hist_field *hist_field,
struct hist_trigger_data *var_data,
unsigned int var_idx)
@@ -1248,6 +1320,7 @@ static struct hist_field *find_event_var(const char *system,
struct hist_elt_data {
char *comm;
u64 *var_ref_vals;
+ char *field_var_str[SYNTH_FIELDS_MAX];
};

static u64 hist_field_var_ref(struct hist_field *hist_field,
@@ -1415,11 +1488,21 @@ static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)

static int parse_action(char *str, struct hist_trigger_attrs *attrs)
{
- int ret = 0;
+ int ret = -EINVAL;

if (attrs->n_actions >= HIST_ACTIONS_MAX)
return ret;

+ if ((strncmp(str, "onmatch(", strlen("onmatch(")) == 0)) {
+ attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
+ if (!attrs->action_str[attrs->n_actions]) {
+ ret = -ENOMEM;
+ return ret;
+ }
+ attrs->n_actions++;
+ ret = 0;
+ }
+
return ret;
}

@@ -1525,7 +1608,14 @@ static inline void save_comm(char *comm, struct task_struct *task)

static void hist_trigger_elt_data_free(struct tracing_map_elt *elt)
{
+ struct hist_trigger_data *hist_data = elt->map->private_data;
struct hist_elt_data *private_data = elt->private_data;
+ unsigned int i, n_str;
+
+ n_str = hist_data->n_field_var_str;
+
+ for (i = 0; i < n_str; i++)
+ kfree(private_data->field_var_str[i]);

kfree(private_data->comm);
kfree(private_data);
@@ -1537,7 +1627,7 @@ static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
unsigned int size = TASK_COMM_LEN + 1;
struct hist_elt_data *elt_data;
struct hist_field *key_field;
- unsigned int i;
+ unsigned int i, n_str;

elt->private_data = elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL);
if (!elt_data)
@@ -1557,6 +1647,16 @@ static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
}
}

+ n_str = hist_data->n_field_var_str;
+
+ for (i = 0; i < n_str; i++) {
+ elt_data->field_var_str[i] = kzalloc(size, GFP_KERNEL);
+ if (!elt_data->field_var_str[i]) {
+ hist_trigger_elt_data_free(elt);
+ return -ENOMEM;
+ }
+ }
+
return 0;
}

@@ -1674,6 +1774,7 @@ static void destroy_hist_field(struct hist_field *hist_field,

kfree(hist_field->var.name);
kfree(hist_field->name);
+ kfree(hist_field->type);

kfree(hist_field);
}
@@ -1704,6 +1805,10 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,

if (flags & HIST_FIELD_FL_HITCOUNT) {
hist_field->fn = hist_field_counter;
+ hist_field->size = sizeof(u64);
+ hist_field->type = kstrdup("u64", GFP_KERNEL);
+ if (!hist_field->type)
+ goto free;
goto out;
}

@@ -1717,12 +1822,18 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
hist_field->fn = hist_field_log2;
hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
hist_field->size = hist_field->operands[0]->size;
+ hist_field->type = kstrdup(hist_field->operands[0]->type, GFP_KERNEL);
+ if (!hist_field->type)
+ goto free;
goto out;
}

if (flags & HIST_FIELD_FL_TIMESTAMP) {
hist_field->fn = hist_field_timestamp;
hist_field->size = sizeof(u64);
+ hist_field->type = kstrdup("u64", GFP_KERNEL);
+ if (!hist_field->type)
+ goto free;
goto out;
}

@@ -1731,6 +1842,10 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,

if (is_string_field(field)) {
flags |= HIST_FIELD_FL_STRING;
+ hist_field->size = MAX_FILTER_STR_VAL;
+ hist_field->type = kstrdup(field->type, GFP_KERNEL);
+ if (!hist_field->type)
+ goto free;

if (field->filter_type == FILTER_STATIC_STRING)
hist_field->fn = hist_field_string;
@@ -1739,6 +1854,12 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
else
hist_field->fn = hist_field_pstring;
} else {
+ hist_field->size = field->size;
+ hist_field->is_signed = field->is_signed;
+ hist_field->type = kstrdup(field->type, GFP_KERNEL);
+ if (!hist_field->type)
+ goto free;
+
hist_field->fn = select_value_fn(field->size,
field->is_signed);
if (!hist_field->fn) {
@@ -1786,7 +1907,10 @@ static struct hist_field *create_var_ref(struct hist_field *var_field)
ref_field->size = var_field->size;
ref_field->is_signed = var_field->is_signed;
ref_field->name = kstrdup(var_field->var.name, GFP_KERNEL);
- if (!ref_field->name) {
+ ref_field->type = kstrdup(var_field->type, GFP_KERNEL);
+ if (!ref_field->name || !ref_field->type) {
+ kfree(ref_field->name);
+ kfree(ref_field->type);
destroy_hist_field(ref_field, 0);
return NULL;
}
@@ -1970,6 +2094,11 @@ static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
expr->operands[0] = operand1;
expr->operator = FIELD_OP_UNARY_MINUS;
expr->name = expr_str(expr, 0);
+ expr->type = kstrdup(operand1->type, GFP_KERNEL);
+ if (!expr->type) {
+ ret = -ENOMEM;
+ goto free;
+ }

return expr;
free:
@@ -2053,6 +2182,11 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
expr->operands[1] = operand2;
expr->operator = field_op;
expr->name = expr_str(expr, 0);
+ expr->type = kstrdup(operand1->type, GFP_KERNEL);
+ if (!expr->type) {
+ ret = -ENOMEM;
+ goto free;
+ }

switch (field_op) {
case FIELD_OP_MINUS:
@@ -2074,6 +2208,718 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
return ERR_PTR(ret);
}

+static struct hist_var_data *find_actions(struct hist_trigger_data *hist_data)
+{
+ struct hist_var_data *var_data, *found = NULL;
+
+ list_for_each_entry(var_data, &hist_action_list, list) {
+ if (var_data->hist_data == hist_data) {
+ found = var_data;
+ break;
+ }
+ }
+
+ return found;
+}
+
+static int save_hist_actions(struct hist_trigger_data *hist_data)
+{
+ struct hist_var_data *var_data;
+
+ var_data = find_actions(hist_data);
+ if (var_data)
+ return 0;
+
+ var_data = kzalloc(sizeof(*var_data), GFP_KERNEL);
+ if (!var_data)
+ return -ENOMEM;
+
+ var_data->hist_data = hist_data;
+ list_add(&var_data->list, &hist_action_list);
+
+ return 0;
+}
+
+static void remove_hist_actions(struct hist_trigger_data *hist_data)
+{
+ struct hist_var_data *var_data;
+
+ var_data = find_actions(hist_data);
+ if (!var_data)
+ return;
+
+ list_del(&var_data->list);
+
+ kfree(var_data);
+}
+
+static char *find_trigger_filter(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file)
+{
+ struct event_trigger_data *test;
+
+ list_for_each_entry_rcu(test, &file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ if (test->private_data == hist_data)
+ return test->filter_str;
+ }
+ }
+
+ return NULL;
+}
+
+static struct event_command trigger_hist_cmd;
+static int event_hist_trigger_func(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param);
+
+static bool compatible_keys(struct hist_trigger_data *target_hist_data,
+ struct hist_trigger_data *hist_data,
+ unsigned int n_keys)
+{
+ struct hist_field *target_hist_field, *hist_field;
+ unsigned int n, i, j;
+
+ if (hist_data->n_fields - hist_data->n_vals != n_keys)
+ return false;
+
+ i = hist_data->n_vals;
+ j = target_hist_data->n_vals;
+
+ for (n = 0; n < n_keys; n++) {
+ hist_field = hist_data->fields[i + n];
+ target_hist_field = hist_data->fields[j + n];
+
+ if (strcmp(hist_field->type, target_hist_field->type) != 0)
+ return false;
+ if (hist_field->size != target_hist_field->size)
+ return false;
+ if (hist_field->is_signed != target_hist_field->is_signed)
+ return false;
+ }
+
+ return true;
+}
+
+static struct hist_trigger_data *
+find_compatible_hist(struct hist_trigger_data *target_hist_data,
+ struct trace_event_file *file)
+{
+ struct hist_trigger_data *hist_data;
+ struct event_trigger_data *test;
+ unsigned int n_keys;
+
+ n_keys = target_hist_data->n_fields - target_hist_data->n_vals;
+
+ list_for_each_entry_rcu(test, &file->triggers, list) {
+ if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ hist_data = test->private_data;
+
+ if (compatible_keys(target_hist_data, hist_data, n_keys))
+ return hist_data;
+ }
+ }
+
+ return NULL;
+}
+
+static struct trace_event_file *event_file(char *system, char *event_name)
+{
+ struct trace_event_file *file;
+ struct trace_array *tr;
+
+ tr = top_trace_array();
+ if (!tr)
+ return ERR_PTR(-ENODEV);
+
+ file = find_event_file(tr, system, event_name);
+ if (!file)
+ return ERR_PTR(-EINVAL);
+
+ return file;
+}
+
+static struct hist_field *
+create_field_var_hist(struct hist_trigger_data *target_hist_data,
+ char *system, char *event_name, char *field_name)
+{
+ struct hist_field *event_var = ERR_PTR(-EINVAL);
+ struct hist_trigger_data *hist_data;
+ unsigned int i, n, first = true;
+ struct field_var_hist *var_hist;
+ struct trace_event_file *file;
+ struct hist_field *key_field;
+ struct trace_array *tr;
+ char *saved_filter;
+ char *cmd;
+ int ret;
+
+ if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX)
+ return ERR_PTR(-EINVAL);
+
+ tr = top_trace_array();
+ if (!tr)
+ return ERR_PTR(-ENODEV);
+
+ file = event_file(system, event_name);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ return ERR_PTR(ret);
+ }
+
+ hist_data = find_compatible_hist(target_hist_data, file);
+ if (!hist_data)
+ return ERR_PTR(-EINVAL);
+
+ var_hist = kzalloc(sizeof(*var_hist), GFP_KERNEL);
+ if (!var_hist)
+ return ERR_PTR(-ENOMEM);
+
+ cmd = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL);
+ if (!cmd) {
+ kfree(var_hist);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ strcat(cmd, "keys=");
+
+ for_each_hist_key_field(i, hist_data) {
+ key_field = hist_data->fields[i];
+ if (!first)
+ strcat(cmd, ",");
+ strcat(cmd, key_field->field->name);
+ first = false;
+ }
+
+ strcat(cmd, ":synthetic_");
+ strcat(cmd, field_name);
+ strcat(cmd, "=");
+ strcat(cmd, field_name);
+
+ saved_filter = find_trigger_filter(hist_data, file);
+ if (saved_filter) {
+ strcat(cmd, " if ");
+ strcat(cmd, saved_filter);
+ }
+
+ var_hist->cmd = kstrdup(cmd, GFP_KERNEL);
+ if (!var_hist->cmd) {
+ kfree(cmd);
+ kfree(var_hist);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ var_hist->hist_data = hist_data;
+
+ ret = event_hist_trigger_func(&trigger_hist_cmd, file,
+ "", "hist", cmd);
+ if (ret) {
+ kfree(cmd);
+ kfree(var_hist->cmd);
+ kfree(var_hist);
+ return ERR_PTR(ret);
+ }
+
+ strcpy(cmd, "synthetic_");
+ strcat(cmd, field_name);
+
+ event_var = find_event_var(system, event_name, cmd);
+ if (!event_var) {
+ kfree(cmd);
+ kfree(var_hist->cmd);
+ kfree(var_hist);
+ return ERR_PTR(-EINVAL);
+ }
+
+ n = target_hist_data->n_field_var_hists;
+ target_hist_data->field_var_hists[n] = var_hist;
+ target_hist_data->n_field_var_hists++;
+
+ return event_var;
+}
+
+static struct hist_field *
+find_target_event_var(struct hist_trigger_data *hist_data,
+ char *system, char *event_name, char *var_name)
+{
+ struct trace_event_file *file = hist_data->event_file;
+ struct hist_field *hist_field = NULL;
+
+ if (system) {
+ struct trace_event_call *call;
+
+ if (!event_name)
+ return NULL;
+
+ call = file->event_call;
+
+ if (strcmp(system, call->class->system) != 0)
+ return NULL;
+
+ if (strcmp(event_name, trace_event_name(call)) != 0)
+ return NULL;
+ }
+
+ hist_field = find_var_field(hist_data, var_name);
+
+ return hist_field;
+}
+
+static inline void __update_field_vars(struct tracing_map_elt *elt,
+ struct ring_buffer_event *rbe,
+ void *rec,
+ struct field_var **field_vars,
+ unsigned int n_field_vars,
+ unsigned int field_var_str_start)
+{
+ struct hist_elt_data *elt_data = elt->private_data;
+ unsigned int i, j, var_idx;
+ u64 var_val;
+
+ for (i = 0, j = field_var_str_start; i < n_field_vars; i++) {
+ struct field_var *field_var = field_vars[i];
+ struct hist_field *var = field_var->var;
+ struct hist_field *val = field_var->val;
+
+ var_val = val->fn(val, elt, rbe, rec);
+ var_idx = var->var.idx;
+
+ if (val->flags & HIST_FIELD_FL_STRING) {
+ char *str = elt_data->field_var_str[j++];
+
+ memcpy(str, (char *)(uintptr_t)var_val,
+ TASK_COMM_LEN + 1);
+ var_val = (u64)(uintptr_t)str;
+ }
+ tracing_map_set_var(elt, var_idx, var_val);
+ }
+}
+
+static void update_field_vars(struct hist_trigger_data *hist_data,
+ struct tracing_map_elt *elt,
+ struct ring_buffer_event *rbe,
+ void *rec)
+{
+ __update_field_vars(elt, rbe, rec, hist_data->field_vars,
+ hist_data->n_field_vars, 0);
+}
+
+static struct hist_field *create_var(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file,
+ char *name, int size, const char *type)
+{
+ struct hist_field *var;
+ int idx;
+
+ if (find_var(file, name) && !hist_data->remove) {
+ var = ERR_PTR(-EINVAL);
+ goto out;
+ }
+
+ var = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
+ if (!var) {
+ var = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ idx = tracing_map_add_var(hist_data->map);
+ if (idx < 0) {
+ kfree(var);
+ var = ERR_PTR(-EINVAL);
+ goto out;
+ }
+
+ var->flags = HIST_FIELD_FL_VAR;
+ var->var.idx = idx;
+ var->var.hist_data = var->hist_data = hist_data;
+ var->size = size;
+ var->var.name = kstrdup(name, GFP_KERNEL);
+ var->type = kstrdup(type, GFP_KERNEL);
+ if (!var->var.name || !var->type) {
+ kfree(var->var.name);
+ kfree(var->type);
+ kfree(var);
+ var = ERR_PTR(-ENOMEM);
+ }
+ out:
+ return var;
+}
+
+static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file,
+ char *field_name)
+{
+ struct hist_field *val = NULL, *var = NULL;
+ unsigned long flags = HIST_FIELD_FL_VAR;
+ struct field_var *field_var;
+ int ret = 0;
+
+ if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) {
+ ret = -EINVAL;
+ goto err;
+ }
+
+ val = parse_atom(hist_data, file, field_name, &flags, NULL);
+ if (IS_ERR(val)) {
+ ret = PTR_ERR(val);
+ goto err;
+ }
+
+ var = create_var(hist_data, file, field_name, val->size, val->type);
+ if (IS_ERR(var)) {
+ kfree(val);
+ ret = PTR_ERR(var);
+ goto err;
+ }
+
+ field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL);
+ if (!field_var) {
+ kfree(val);
+ kfree(var);
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ field_var->var = var;
+ field_var->val = val;
+ out:
+ return field_var;
+ err:
+ field_var = ERR_PTR(ret);
+ goto out;
+}
+
+static struct field_var *
+create_target_field_var(struct hist_trigger_data *hist_data,
+ char *system, char *event_name, char *var_name)
+{
+ struct trace_event_file *file = hist_data->event_file;
+
+ if (system) {
+ struct trace_event_call *call;
+
+ if (!event_name)
+ return NULL;
+
+ call = file->event_call;
+
+ if (strcmp(system, call->class->system) != 0)
+ return NULL;
+
+ if (strcmp(event_name, trace_event_name(call)) != 0)
+ return NULL;
+ }
+
+ return create_field_var(hist_data, file, var_name);
+}
+
+static void onmatch_destroy(struct action_data *data)
+{
+ unsigned int i;
+
+ kfree(data->match_event);
+ kfree(data->match_event_system);
+ kfree(data->synth_event_name);
+
+ for (i = 0; i < data->n_params; i++)
+ kfree(data->params[i]);
+
+ kfree(data);
+}
+
+static void destroy_field_var(struct field_var *field_var)
+{
+ if (!field_var)
+ return;
+
+ destroy_hist_field(field_var->var, 0);
+ destroy_hist_field(field_var->val, 0);
+
+ kfree(field_var);
+}
+
+static void destroy_field_vars(struct hist_trigger_data *hist_data)
+{
+ unsigned int i;
+
+ for (i = 0; i < hist_data->n_field_vars; i++)
+ destroy_field_var(hist_data->field_vars[i]);
+}
+
+static void save_field_var(struct hist_trigger_data *hist_data,
+ struct field_var *field_var)
+{
+ hist_data->field_vars[hist_data->n_field_vars++] = field_var;
+
+ if (field_var->val->flags & HIST_FIELD_FL_STRING)
+ hist_data->n_field_var_str++;
+}
+
+static void destroy_synth_var_refs(struct hist_trigger_data *hist_data)
+{
+ unsigned int i;
+
+ for (i = 0; i < hist_data->n_synth_var_refs; i++)
+ destroy_hist_field(hist_data->synth_var_refs[i], 0);
+}
+
+static void save_synth_var_ref(struct hist_trigger_data *hist_data,
+ struct hist_field *var_ref)
+{
+ hist_data->synth_var_refs[hist_data->n_synth_var_refs++] = var_ref;
+
+ hist_data->var_refs[hist_data->n_var_refs] = var_ref;
+ var_ref->var_ref_idx = hist_data->n_var_refs++;
+}
+
+static int check_synth_field(struct synth_event *event,
+ struct hist_field *hist_field,
+ unsigned int field_pos)
+{
+ struct synth_field *field;
+
+ if (field_pos >= event->n_fields)
+ return -EINVAL;
+
+ field = event->fields[field_pos];
+
+ if (strcmp(field->type, hist_field->type) != 0)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int parse_action_params(char *params, struct action_data *data)
+{
+ char *param, *saved_param;
+ int ret = 0;
+
+ while (params) {
+ if (data->n_params >= SYNTH_FIELDS_MAX)
+ goto out;
+
+ param = strsep(&params, ",");
+ if (!param)
+ goto out;
+
+ param = strstrip(param);
+ if (strlen(param) < 2) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ saved_param = kstrdup(param, GFP_KERNEL);
+ if (!saved_param) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ data->params[data->n_params++] = saved_param;
+ }
+ out:
+ return ret;
+}
+
+static struct hist_field *
+onmatch_find_var(struct hist_trigger_data *hist_data, struct action_data *data,
+ char *system, char *event, char *var)
+{
+ struct hist_field *hist_field;
+
+ var++; /* skip '$' */
+
+ hist_field = find_target_event_var(hist_data, system, event, var);
+ if (!hist_field) {
+ if (!system) {
+ system = data->match_event_system;
+ event = data->match_event;
+ }
+
+ hist_field = find_event_var(system, event, var);
+ }
+
+ return hist_field;
+}
+
+static struct hist_field *
+onmatch_create_field_var(struct hist_trigger_data *hist_data,
+ struct action_data *data, char *system,
+ char *event, char *var)
+{
+ struct hist_field *hist_field = NULL;
+ struct field_var *field_var;
+
+ field_var = create_target_field_var(hist_data, system, event, var);
+ if (IS_ERR(field_var))
+ goto out;
+
+ if (field_var) {
+ save_field_var(hist_data, field_var);
+ hist_field = field_var->var;
+ } else {
+ if (!system) {
+ system = data->match_event_system;
+ event = data->match_event;
+ }
+
+ hist_field = create_field_var_hist(hist_data, system, event, var);
+ if (IS_ERR(hist_field))
+ goto free;
+ }
+ out:
+ return hist_field;
+ free:
+ destroy_field_var(field_var);
+ hist_field = NULL;
+ goto out;
+}
+
+static int onmatch_create(struct hist_trigger_data *hist_data,
+ struct trace_event_file *file,
+ struct action_data *data)
+{
+ char *event_name, *param, *system = NULL;
+ struct hist_field *hist_field, *var_ref;
+ unsigned int i, var_ref_idx;
+ unsigned int field_pos = 0;
+ struct synth_event *event;
+ int ret = 0;
+
+ mutex_lock(&synth_event_mutex);
+
+ event = find_synth_event(data->synth_event_name);
+ if (!event) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ var_ref_idx = hist_data->n_var_refs;
+
+ for (i = 0; i < data->n_params; i++) {
+ char *p;
+
+ p = param = kstrdup(data->params[i], GFP_KERNEL);
+ if (!param)
+ goto out;
+
+ system = strsep(&param, ".");
+ if (!param) {
+ param = (char *)system;
+ system = event_name = NULL;
+ } else {
+ event_name = strsep(&param, ".");
+ if (!param) {
+ kfree(p);
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ if (param[0] == '$')
+ hist_field = onmatch_find_var(hist_data, data, system,
+ event_name, param);
+ else
+ hist_field = onmatch_create_field_var(hist_data, data,
+ system,
+ event_name,
+ param);
+
+ if (!hist_field) {
+ kfree(p);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (check_synth_field(event, hist_field, field_pos) == 0) {
+ var_ref = create_var_ref(hist_field);
+ if (!var_ref) {
+ kfree(p);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ save_synth_var_ref(hist_data, var_ref);
+ field_pos++;
+ kfree(p);
+ continue;
+ }
+
+ kfree(p);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (field_pos != event->n_fields) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ data->fn = action_trace;
+ data->synth_event = event;
+ data->var_ref_idx = var_ref_idx;
+ hist_data->actions[hist_data->n_actions++] = data;
+ save_hist_actions(hist_data);
+ out:
+ mutex_unlock(&synth_event_mutex);
+
+ return ret;
+}
+
+static struct action_data *onmatch_parse(char *str)
+{
+ char *match_event, *match_event_system;
+ char *synth_event_name, *params;
+ struct action_data *data;
+ int ret = -EINVAL;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return ERR_PTR(-ENOMEM);
+
+ match_event = strsep(&str, ")");
+ if (!match_event || !str)
+ goto free;
+
+ match_event_system = strsep(&match_event, ".");
+ if (!match_event)
+ goto free;
+
+ if (IS_ERR(event_file(match_event_system, match_event)))
+ goto free;
+
+ data->match_event = kstrdup(match_event, GFP_KERNEL);
+ data->match_event_system = kstrdup(match_event_system, GFP_KERNEL);
+
+ strsep(&str, ".");
+ if (!str)
+ goto free;
+
+ synth_event_name = strsep(&str, "(");
+ if (!synth_event_name || !str)
+ goto free;
+ data->synth_event_name = kstrdup(synth_event_name, GFP_KERNEL);
+
+ params = strsep(&str, ")");
+ if (!params || !str || (str && strlen(str)))
+ goto free;
+
+ ret = parse_action_params(params, data);
+ if (ret)
+ goto free;
+
+ if (!data->match_event_system || !data->match_event ||
+ !data->synth_event_name) {
+ ret = -ENOMEM;
+ goto free;
+ }
+ out:
+ return data;
+ free:
+ onmatch_destroy(data);
+ data = ERR_PTR(ret);
+ goto out;
+}
+
static int create_hitcount_val(struct hist_trigger_data *hist_data)
{
hist_data->fields[HITCOUNT_IDX] =
@@ -2465,19 +3311,37 @@ static void destroy_actions(struct hist_trigger_data *hist_data)
for (i = 0; i < hist_data->n_actions; i++) {
struct action_data *data = hist_data->actions[i];

- kfree(data);
+ if (data->fn == action_trace)
+ onmatch_destroy(data);
+ else
+ kfree(data);
}
}

static int create_actions(struct hist_trigger_data *hist_data,
struct trace_event_file *file)
{
+ struct action_data *data;
unsigned int i;
int ret = 0;
char *str;

for (i = 0; i < hist_data->attrs->n_actions; i++) {
str = hist_data->attrs->action_str[i];
+
+ if (strncmp(str, "onmatch(", strlen("onmatch(")) == 0) {
+ char *action_str = str + strlen("onmatch(");
+
+ data = onmatch_parse(action_str);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ ret = onmatch_create(hist_data, file, data);
+ if (ret) {
+ onmatch_destroy(data);
+ return ret;
+ }
+ }
}

return ret;
@@ -2494,6 +3358,26 @@ static void print_actions(struct seq_file *m,
}
}

+static void print_onmatch_spec(struct seq_file *m,
+ struct hist_trigger_data *hist_data,
+ struct action_data *data)
+{
+ unsigned int i;
+
+ seq_printf(m, ":onmatch(%s.%s).", data->match_event_system,
+ data->match_event);
+
+ seq_printf(m, "%s(", data->synth_event->name);
+
+ for (i = 0; i < data->n_params; i++) {
+ if (i)
+ seq_puts(m, ",");
+ seq_printf(m, "%s", data->params[i]);
+ }
+
+ seq_puts(m, ")");
+}
+
static void print_actions_spec(struct seq_file *m,
struct hist_trigger_data *hist_data)
{
@@ -2501,6 +3385,19 @@ static void print_actions_spec(struct seq_file *m,

for (i = 0; i < hist_data->n_actions; i++) {
struct action_data *data = hist_data->actions[i];
+
+ if (data->fn == action_trace)
+ print_onmatch_spec(m, hist_data, data);
+ }
+}
+
+static void destroy_field_var_hists(struct hist_trigger_data *hist_data)
+{
+ unsigned int i;
+
+ for (i = 0; i < hist_data->n_field_var_hists; i++) {
+ kfree(hist_data->field_var_hists[i]->cmd);
+ kfree(hist_data->field_var_hists[i]);
}
}

@@ -2514,6 +3411,9 @@ static void destroy_hist_data(struct hist_trigger_data *hist_data)
tracing_map_destroy(hist_data->map);

destroy_actions(hist_data);
+ destroy_field_vars(hist_data);
+ destroy_field_var_hists(hist_data);
+ destroy_synth_var_refs(hist_data);

kfree(hist_data);
}
@@ -2648,6 +3548,8 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
tracing_map_set_var(elt, var_idx, hist_val);
}
}
+
+ update_field_vars(hist_data, elt, rbe, rec);
}

static inline void add_to_key(char *compound_key, void *key,
@@ -2861,6 +3763,8 @@ static void hist_trigger_stacktrace_print(struct seq_file *m,
}
}

+ print_actions(m, hist_data, elt);
+
seq_puts(m, "\n");
}

@@ -3128,6 +4032,8 @@ static void event_hist_trigger_free(struct event_trigger_ops *ops,

remove_hist_vars(hist_data);

+ remove_hist_actions(hist_data);
+
destroy_hist_data(hist_data);
}
}
@@ -3390,6 +4296,21 @@ static bool hist_trigger_check_refs(struct event_trigger_data *data,
return false;
}

+static void unregister_field_var_hists(struct hist_trigger_data *hist_data)
+{
+ struct trace_event_file *file;
+ unsigned int i;
+ char *cmd;
+ int ret;
+
+ for (i = 0; i < hist_data->n_field_var_hists; i++) {
+ file = hist_data->field_var_hists[i]->hist_data->event_file;
+ cmd = hist_data->field_var_hists[i]->cmd;
+ ret = event_hist_trigger_func(&trigger_hist_cmd, file,
+ "!hist", "hist", cmd);
+ }
+}
+
static void hist_unregister_trigger(char *glob, struct event_trigger_ops *ops,
struct event_trigger_data *data,
struct trace_event_file *file)
@@ -3405,6 +4326,7 @@ static void hist_unregister_trigger(char *glob, struct event_trigger_ops *ops,
if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
if (!hist_trigger_match(data, test, named_data, false))
continue;
+ unregister_field_var_hists(test->private_data);
unregistered = true;
list_del_rcu(&test->list);
trace_event_trigger_enable_disable(file, 0);
@@ -3448,6 +4370,7 @@ static void hist_unreg_all(struct trace_event_file *file)

list_for_each_entry_safe(test, n, &file->triggers, list) {
if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
+ unregister_field_var_hists(test->private_data);
list_del_rcu(&test->list);
trace_event_trigger_enable_disable(file, 0);
update_cond_flag(file);
@@ -3571,6 +4494,8 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,

remove_hist_vars(hist_data);

+ remove_hist_actions(hist_data);
+
kfree(trigger_data);
destroy_hist_data(hist_data);

--
1.9.3