Merge branch 'linus' into perf/core, to refresh the branch

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 1755 insertions, 0 deletions

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
new file mode 100644
index 000000000000..0c05b8a99806
--- /dev/null
+++ b/kernel/trace/trace_events_hist.c
@@ -0,0 +1,1755 @@
+/*
+ * trace_events_hist - trace event hist 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.
+ *
+ * Copyright (C) 2015 Tom Zanussi <tom.zanussi@linux.intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/stacktrace.h>
+
+#include "tracing_map.h"
+#include "trace.h"
+
+struct hist_field;
+
+typedef u64 (*hist_field_fn_t) (struct hist_field *field, void *event);
+
+struct hist_field {
+	struct ftrace_event_field	*field;
+	unsigned long			flags;
+	hist_field_fn_t			fn;
+	unsigned int			size;
+	unsigned int			offset;
+};
+
+static u64 hist_field_none(struct hist_field *field, void *event)
+{
+	return 0;
+}
+
+static u64 hist_field_counter(struct hist_field *field, void *event)
+{
+	return 1;
+}
+
+static u64 hist_field_string(struct hist_field *hist_field, void *event)
+{
+	char *addr = (char *)(event + hist_field->field->offset);
+
+	return (u64)(unsigned long)addr;
+}
+
+static u64 hist_field_dynstring(struct hist_field *hist_field, void *event)
+{
+	u32 str_item = *(u32 *)(event + hist_field->field->offset);
+	int str_loc = str_item & 0xffff;
+	char *addr = (char *)(event + str_loc);
+
+	return (u64)(unsigned long)addr;
+}
+
+static u64 hist_field_pstring(struct hist_field *hist_field, void *event)
+{
+	char **addr = (char **)(event + hist_field->field->offset);
+
+	return (u64)(unsigned long)*addr;
+}
+
+static u64 hist_field_log2(struct hist_field *hist_field, void *event)
+{
+	u64 val = *(u64 *)(event + hist_field->field->offset);
+
+	return (u64) ilog2(roundup_pow_of_two(val));
+}
+
+#define DEFINE_HIST_FIELD_FN(type)					\
+static u64 hist_field_##type(struct hist_field *hist_field, void *event)\
+{									\
+	type *addr = (type *)(event + hist_field->field->offset);	\
+									\
+	return (u64)(unsigned long)*addr;				\
+}
+
+DEFINE_HIST_FIELD_FN(s64);
+DEFINE_HIST_FIELD_FN(u64);
+DEFINE_HIST_FIELD_FN(s32);
+DEFINE_HIST_FIELD_FN(u32);
+DEFINE_HIST_FIELD_FN(s16);
+DEFINE_HIST_FIELD_FN(u16);
+DEFINE_HIST_FIELD_FN(s8);
+DEFINE_HIST_FIELD_FN(u8);
+
+#define for_each_hist_field(i, hist_data)	\
+	for ((i) = 0; (i) < (hist_data)->n_fields; (i)++)
+
+#define for_each_hist_val_field(i, hist_data)	\
+	for ((i) = 0; (i) < (hist_data)->n_vals; (i)++)
+
+#define for_each_hist_key_field(i, hist_data)	\
+	for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
+
+#define HIST_STACKTRACE_DEPTH	16
+#define HIST_STACKTRACE_SIZE	(HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
+#define HIST_STACKTRACE_SKIP	5
+
+#define HITCOUNT_IDX		0
+#define HIST_KEY_SIZE_MAX	(MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
+
+enum hist_field_flags {
+	HIST_FIELD_FL_HITCOUNT		= 1,
+	HIST_FIELD_FL_KEY		= 2,
+	HIST_FIELD_FL_STRING		= 4,
+	HIST_FIELD_FL_HEX		= 8,
+	HIST_FIELD_FL_SYM		= 16,
+	HIST_FIELD_FL_SYM_OFFSET	= 32,
+	HIST_FIELD_FL_EXECNAME		= 64,
+	HIST_FIELD_FL_SYSCALL		= 128,
+	HIST_FIELD_FL_STACKTRACE	= 256,
+	HIST_FIELD_FL_LOG2		= 512,
+};
+
+struct hist_trigger_attrs {
+	char		*keys_str;
+	char		*vals_str;
+	char		*sort_key_str;
+	char		*name;
+	bool		pause;
+	bool		cont;
+	bool		clear;
+	unsigned int	map_bits;
+};
+
+struct hist_trigger_data {
+	struct hist_field               *fields[TRACING_MAP_FIELDS_MAX];
+	unsigned int			n_vals;
+	unsigned int			n_keys;
+	unsigned int			n_fields;
+	unsigned int			key_size;
+	struct tracing_map_sort_key	sort_keys[TRACING_MAP_SORT_KEYS_MAX];
+	unsigned int			n_sort_keys;
+	struct trace_event_file		*event_file;
+	struct hist_trigger_attrs	*attrs;
+	struct tracing_map		*map;
+};
+
+static hist_field_fn_t select_value_fn(int field_size, int field_is_signed)
+{
+	hist_field_fn_t fn = NULL;
+
+	switch (field_size) {
+	case 8:
+		if (field_is_signed)
+			fn = hist_field_s64;
+		else
+			fn = hist_field_u64;
+		break;
+	case 4:
+		if (field_is_signed)
+			fn = hist_field_s32;
+		else
+			fn = hist_field_u32;
+		break;
+	case 2:
+		if (field_is_signed)
+			fn = hist_field_s16;
+		else
+			fn = hist_field_u16;
+		break;
+	case 1:
+		if (field_is_signed)
+			fn = hist_field_s8;
+		else
+			fn = hist_field_u8;
+		break;
+	}
+
+	return fn;
+}
+
+static int parse_map_size(char *str)
+{
+	unsigned long size, map_bits;
+	int ret;
+
+	strsep(&str, "=");
+	if (!str) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = kstrtoul(str, 0, &size);
+	if (ret)
+		goto out;
+
+	map_bits = ilog2(roundup_pow_of_two(size));
+	if (map_bits < TRACING_MAP_BITS_MIN ||
+	    map_bits > TRACING_MAP_BITS_MAX)
+		ret = -EINVAL;
+	else
+		ret = map_bits;
+ out:
+	return ret;
+}
+
+static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
+{
+	if (!attrs)
+		return;
+
+	kfree(attrs->name);
+	kfree(attrs->sort_key_str);
+	kfree(attrs->keys_str);
+	kfree(attrs->vals_str);
+	kfree(attrs);
+}
+
+static struct hist_trigger_attrs *parse_hist_trigger_attrs(char *trigger_str)
+{
+	struct hist_trigger_attrs *attrs;
+	int ret = 0;
+
+	attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
+	if (!attrs)
+		return ERR_PTR(-ENOMEM);
+
+	while (trigger_str) {
+		char *str = strsep(&trigger_str, ":");
+
+		if ((strncmp(str, "key=", strlen("key=")) == 0) ||
+		    (strncmp(str, "keys=", strlen("keys=")) == 0))
+			attrs->keys_str = kstrdup(str, GFP_KERNEL);
+		else if ((strncmp(str, "val=", strlen("val=")) == 0) ||
+			 (strncmp(str, "vals=", strlen("vals=")) == 0) ||
+			 (strncmp(str, "values=", strlen("values=")) == 0))
+			attrs->vals_str = kstrdup(str, GFP_KERNEL);
+		else if (strncmp(str, "sort=", strlen("sort=")) == 0)
+			attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
+		else if (strncmp(str, "name=", strlen("name=")) == 0)
+			attrs->name = kstrdup(str, GFP_KERNEL);
+		else if (strcmp(str, "pause") == 0)
+			attrs->pause = true;
+		else if ((strcmp(str, "cont") == 0) ||
+			 (strcmp(str, "continue") == 0))
+			attrs->cont = true;
+		else if (strcmp(str, "clear") == 0)
+			attrs->clear = true;
+		else if (strncmp(str, "size=", strlen("size=")) == 0) {
+			int map_bits = parse_map_size(str);
+
+			if (map_bits < 0) {
+				ret = map_bits;
+				goto free;
+			}
+			attrs->map_bits = map_bits;
+		} else {
+			ret = -EINVAL;
+			goto free;
+		}
+	}
+
+	if (!attrs->keys_str) {
+		ret = -EINVAL;
+		goto free;
+	}
+
+	return attrs;
+ free:
+	destroy_hist_trigger_attrs(attrs);
+
+	return ERR_PTR(ret);
+}
+
+static inline void save_comm(char *comm, struct task_struct *task)
+{
+	if (!task->pid) {
+		strcpy(comm, "<idle>");
+		return;
+	}
+
+	if (WARN_ON_ONCE(task->pid < 0)) {
+		strcpy(comm, "<XXX>");
+		return;
+	}
+
+	memcpy(comm, task->comm, TASK_COMM_LEN);
+}
+
+static void hist_trigger_elt_comm_free(struct tracing_map_elt *elt)
+{
+	kfree((char *)elt->private_data);
+}
+
+static int hist_trigger_elt_comm_alloc(struct tracing_map_elt *elt)
+{
+	struct hist_trigger_data *hist_data = elt->map->private_data;
+	struct hist_field *key_field;
+	unsigned int i;
+
+	for_each_hist_key_field(i, hist_data) {
+		key_field = hist_data->fields[i];
+
+		if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
+			unsigned int size = TASK_COMM_LEN + 1;
+
+			elt->private_data = kzalloc(size, GFP_KERNEL);
+			if (!elt->private_data)
+				return -ENOMEM;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static void hist_trigger_elt_comm_copy(struct tracing_map_elt *to,
+				       struct tracing_map_elt *from)
+{
+	char *comm_from = from->private_data;
+	char *comm_to = to->private_data;
+
+	if (comm_from)
+		memcpy(comm_to, comm_from, TASK_COMM_LEN + 1);
+}
+
+static void hist_trigger_elt_comm_init(struct tracing_map_elt *elt)
+{
+	char *comm = elt->private_data;
+
+	if (comm)
+		save_comm(comm, current);
+}
+
+static const struct tracing_map_ops hist_trigger_elt_comm_ops = {
+	.elt_alloc	= hist_trigger_elt_comm_alloc,
+	.elt_copy	= hist_trigger_elt_comm_copy,
+	.elt_free	= hist_trigger_elt_comm_free,
+	.elt_init	= hist_trigger_elt_comm_init,
+};
+
+static void destroy_hist_field(struct hist_field *hist_field)
+{
+	kfree(hist_field);
+}
+
+static struct hist_field *create_hist_field(struct ftrace_event_field *field,
+					    unsigned long flags)
+{
+	struct hist_field *hist_field;
+
+	if (field && is_function_field(field))
+		return NULL;
+
+	hist_field = kzalloc(sizeof(struct hist_field), GFP_KERNEL);
+	if (!hist_field)
+		return NULL;
+
+	if (flags & HIST_FIELD_FL_HITCOUNT) {
+		hist_field->fn = hist_field_counter;
+		goto out;
+	}
+
+	if (flags & HIST_FIELD_FL_STACKTRACE) {
+		hist_field->fn = hist_field_none;
+		goto out;
+	}
+
+	if (flags & HIST_FIELD_FL_LOG2) {
+		hist_field->fn = hist_field_log2;
+		goto out;
+	}
+
+	if (WARN_ON_ONCE(!field))
+		goto out;
+
+	if (is_string_field(field)) {
+		flags |= HIST_FIELD_FL_STRING;
+
+		if (field->filter_type == FILTER_STATIC_STRING)
+			hist_field->fn = hist_field_string;
+		else if (field->filter_type == FILTER_DYN_STRING)
+			hist_field->fn = hist_field_dynstring;
+		else
+			hist_field->fn = hist_field_pstring;
+	} else {
+		hist_field->fn = select_value_fn(field->size,
+						 field->is_signed);
+		if (!hist_field->fn) {
+			destroy_hist_field(hist_field);
+			return NULL;
+		}
+	}
+ out:
+	hist_field->field = field;
+	hist_field->flags = flags;
+
+	return hist_field;
+}
+
+static void destroy_hist_fields(struct hist_trigger_data *hist_data)
+{
+	unsigned int i;
+
+	for (i = 0; i < TRACING_MAP_FIELDS_MAX; i++) {
+		if (hist_data->fields[i]) {
+			destroy_hist_field(hist_data->fields[i]);
+			hist_data->fields[i] = NULL;
+		}
+	}
+}
+
+static int create_hitcount_val(struct hist_trigger_data *hist_data)
+{
+	hist_data->fields[HITCOUNT_IDX] =
+		create_hist_field(NULL, HIST_FIELD_FL_HITCOUNT);
+	if (!hist_data->fields[HITCOUNT_IDX])
+		return -ENOMEM;
+
+	hist_data->n_vals++;
+
+	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int create_val_field(struct hist_trigger_data *hist_data,
+			    unsigned int val_idx,
+			    struct trace_event_file *file,
+			    char *field_str)
+{
+	struct ftrace_event_field *field = NULL;
+	unsigned long flags = 0;
+	char *field_name;
+	int ret = 0;
+
+	if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
+		return -EINVAL;
+
+	field_name = strsep(&field_str, ".");
+	if (field_str) {
+		if (strcmp(field_str, "hex") == 0)
+			flags |= HIST_FIELD_FL_HEX;
+		else {
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+	field = trace_find_event_field(file->event_call, field_name);
+	if (!field) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	hist_data->fields[val_idx] = create_hist_field(field, flags);
+	if (!hist_data->fields[val_idx]) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	++hist_data->n_vals;
+
+	if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
+		ret = -EINVAL;
+ out:
+	return ret;
+}
+
+static int create_val_fields(struct hist_trigger_data *hist_data,
+			     struct trace_event_file *file)
+{
+	char *fields_str, *field_str;
+	unsigned int i, j;
+	int ret;
+
+	ret = create_hitcount_val(hist_data);
+	if (ret)
+		goto out;
+
+	fields_str = hist_data->attrs->vals_str;
+	if (!fields_str)
+		goto out;
+
+	strsep(&fields_str, "=");
+	if (!fields_str)
+		goto out;
+
+	for (i = 0, j = 1; i < TRACING_MAP_VALS_MAX &&
+		     j < TRACING_MAP_VALS_MAX; i++) {
+		field_str = strsep(&fields_str, ",");
+		if (!field_str)
+			break;
+		if (strcmp(field_str, "hitcount") == 0)
+			continue;
+		ret = create_val_field(hist_data, j++, file, field_str);
+		if (ret)
+			goto out;
+	}
+	if (fields_str && (strcmp(fields_str, "hitcount") != 0))
+		ret = -EINVAL;
+ out:
+	return ret;
+}
+
+static int create_key_field(struct hist_trigger_data *hist_data,
+			    unsigned int key_idx,
+			    unsigned int key_offset,
+			    struct trace_event_file *file,
+			    char *field_str)
+{
+	struct ftrace_event_field *field = NULL;
+	unsigned long flags = 0;
+	unsigned int key_size;
+	int ret = 0;
+
+	if (WARN_ON(key_idx >= TRACING_MAP_FIELDS_MAX))
+		return -EINVAL;
+
+	flags |= HIST_FIELD_FL_KEY;
+
+	if (strcmp(field_str, "stacktrace") == 0) {
+		flags |= HIST_FIELD_FL_STACKTRACE;
+		key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
+	} else {
+		char *field_name = strsep(&field_str, ".");
+
+		if (field_str) {
+			if (strcmp(field_str, "hex") == 0)
+				flags |= HIST_FIELD_FL_HEX;
+			else if (strcmp(field_str, "sym") == 0)
+				flags |= HIST_FIELD_FL_SYM;
+			else if (strcmp(field_str, "sym-offset") == 0)
+				flags |= HIST_FIELD_FL_SYM_OFFSET;
+			else if ((strcmp(field_str, "execname") == 0) &&
+				 (strcmp(field_name, "common_pid") == 0))
+				flags |= HIST_FIELD_FL_EXECNAME;
+			else if (strcmp(field_str, "syscall") == 0)
+				flags |= HIST_FIELD_FL_SYSCALL;
+			else if (strcmp(field_str, "log2") == 0)
+				flags |= HIST_FIELD_FL_LOG2;
+			else {
+				ret = -EINVAL;
+				goto out;
+			}
+		}
+
+		field = trace_find_event_field(file->event_call, field_name);
+		if (!field) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		if (is_string_field(field))
+			key_size = MAX_FILTER_STR_VAL;
+		else
+			key_size = field->size;
+	}
+
+	hist_data->fields[key_idx] = create_hist_field(field, flags);
+	if (!hist_data->fields[key_idx]) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	key_size = ALIGN(key_size, sizeof(u64));
+	hist_data->fields[key_idx]->size = key_size;
+	hist_data->fields[key_idx]->offset = key_offset;
+	hist_data->key_size += key_size;
+	if (hist_data->key_size > HIST_KEY_SIZE_MAX) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	hist_data->n_keys++;
+
+	if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
+		return -EINVAL;
+
+	ret = key_size;
+ out:
+	return ret;
+}
+
+static int create_key_fields(struct hist_trigger_data *hist_data,
+			     struct trace_event_file *file)
+{
+	unsigned int i, key_offset = 0, n_vals = hist_data->n_vals;
+	char *fields_str, *field_str;
+	int ret = -EINVAL;
+
+	fields_str = hist_data->attrs->keys_str;
+	if (!fields_str)
+		goto out;
+
+	strsep(&fields_str, "=");
+	if (!fields_str)
+		goto out;
+
+	for (i = n_vals; i < n_vals + TRACING_MAP_KEYS_MAX; i++) {
+		field_str = strsep(&fields_str, ",");
+		if (!field_str)
+			break;
+		ret = create_key_field(hist_data, i, key_offset,
+				       file, field_str);
+		if (ret < 0)
+			goto out;
+		key_offset += ret;
+	}
+	if (fields_str) {
+		ret = -EINVAL;
+		goto out;
+	}
+	ret = 0;
+ out:
+	return ret;
+}
+
+static int create_hist_fields(struct hist_trigger_data *hist_data,
+			      struct trace_event_file *file)
+{
+	int ret;
+
+	ret = create_val_fields(hist_data, file);
+	if (ret)
+		goto out;
+
+	ret = create_key_fields(hist_data, file);
+	if (ret)
+		goto out;
+
+	hist_data->n_fields = hist_data->n_vals + hist_data->n_keys;
+ out:
+	return ret;
+}
+
+static int is_descending(const char *str)
+{
+	if (!str)
+		return 0;
+
+	if (strcmp(str, "descending") == 0)
+		return 1;
+
+	if (strcmp(str, "ascending") == 0)
+		return 0;
+
+	return -EINVAL;
+}
+
+static int create_sort_keys(struct hist_trigger_data *hist_data)
+{
+	char *fields_str = hist_data->attrs->sort_key_str;
+	struct ftrace_event_field *field = NULL;
+	struct tracing_map_sort_key *sort_key;
+	int descending, ret = 0;
+	unsigned int i, j;
+
+	hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */
+
+	if (!fields_str)
+		goto out;
+
+	strsep(&fields_str, "=");
+	if (!fields_str) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	for (i = 0; i < TRACING_MAP_SORT_KEYS_MAX; i++) {
+		char *field_str, *field_name;
+
+		sort_key = &hist_data->sort_keys[i];
+
+		field_str = strsep(&fields_str, ",");
+		if (!field_str) {
+			if (i == 0)
+				ret = -EINVAL;
+			break;
+		}
+
+		if ((i == TRACING_MAP_SORT_KEYS_MAX - 1) && fields_str) {
+			ret = -EINVAL;
+			break;
+		}
+
+		field_name = strsep(&field_str, ".");
+		if (!field_name) {
+			ret = -EINVAL;
+			break;
+		}
+
+		if (strcmp(field_name, "hitcount") == 0) {
+			descending = is_descending(field_str);
+			if (descending < 0) {
+				ret = descending;
+				break;
+			}
+			sort_key->descending = descending;
+			continue;
+		}
+
+		for (j = 1; j < hist_data->n_fields; j++) {
+			field = hist_data->fields[j]->field;
+			if (field && (strcmp(field_name, field->name) == 0)) {
+				sort_key->field_idx = j;
+				descending = is_descending(field_str);
+				if (descending < 0) {
+					ret = descending;
+					goto out;
+				}
+				sort_key->descending = descending;
+				break;
+			}
+		}
+		if (j == hist_data->n_fields) {
+			ret = -EINVAL;
+			break;
+		}
+	}
+	hist_data->n_sort_keys = i;
+ out:
+	return ret;
+}
+
+static void destroy_hist_data(struct hist_trigger_data *hist_data)
+{
+	destroy_hist_trigger_attrs(hist_data->attrs);
+	destroy_hist_fields(hist_data);
+	tracing_map_destroy(hist_data->map);
+	kfree(hist_data);
+}
+
+static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
+{
+	struct tracing_map *map = hist_data->map;
+	struct ftrace_event_field *field;
+	struct hist_field *hist_field;
+	int i, idx;
+
+	for_each_hist_field(i, hist_data) {
+		hist_field = hist_data->fields[i];
+		if (hist_field->flags & HIST_FIELD_FL_KEY) {
+			tracing_map_cmp_fn_t cmp_fn;
+
+			field = hist_field->field;
+
+			if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
+				cmp_fn = tracing_map_cmp_none;
+			else if (is_string_field(field))
+				cmp_fn = tracing_map_cmp_string;
+			else
+				cmp_fn = tracing_map_cmp_num(field->size,
+							     field->is_signed);
+			idx = tracing_map_add_key_field(map,
+							hist_field->offset,
+							cmp_fn);
+
+		} else
+			idx = tracing_map_add_sum_field(map);
+
+		if (idx < 0)
+			return idx;
+	}
+
+	return 0;
+}
+
+static bool need_tracing_map_ops(struct hist_trigger_data *hist_data)
+{
+	struct hist_field *key_field;
+	unsigned int i;
+
+	for_each_hist_key_field(i, hist_data) {
+		key_field = hist_data->fields[i];
+
+		if (key_field->flags & HIST_FIELD_FL_EXECNAME)
+			return true;
+	}
+
+	return false;
+}
+
+static struct hist_trigger_data *
+create_hist_data(unsigned int map_bits,
+		 struct hist_trigger_attrs *attrs,
+		 struct trace_event_file *file)
+{
+	const struct tracing_map_ops *map_ops = NULL;
+	struct hist_trigger_data *hist_data;
+	int ret = 0;
+
+	hist_data = kzalloc(sizeof(*hist_data), GFP_KERNEL);
+	if (!hist_data)
+		return ERR_PTR(-ENOMEM);
+
+	hist_data->attrs = attrs;
+
+	ret = create_hist_fields(hist_data, file);
+	if (ret)
+		goto free;
+
+	ret = create_sort_keys(hist_data);
+	if (ret)
+		goto free;
+
+	if (need_tracing_map_ops(hist_data))
+		map_ops = &hist_trigger_elt_comm_ops;
+
+	hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
+					    map_ops, hist_data);
+	if (IS_ERR(hist_data->map)) {
+		ret = PTR_ERR(hist_data->map);
+		hist_data->map = NULL;
+		goto free;
+	}
+
+	ret = create_tracing_map_fields(hist_data);
+	if (ret)
+		goto free;
+
+	ret = tracing_map_init(hist_data->map);
+	if (ret)
+		goto free;
+
+	hist_data->event_file = file;
+ out:
+	return hist_data;
+ free:
+	hist_data->attrs = NULL;
+
+	destroy_hist_data(hist_data);
+
+	hist_data = ERR_PTR(ret);
+
+	goto out;
+}
+
+static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
+				    struct tracing_map_elt *elt,
+				    void *rec)
+{
+	struct hist_field *hist_field;
+	unsigned int i;
+	u64 hist_val;
+
+	for_each_hist_val_field(i, hist_data) {
+		hist_field = hist_data->fields[i];
+		hist_val = hist_field->fn(hist_field, rec);
+		tracing_map_update_sum(elt, i, hist_val);
+	}
+}
+
+static inline void add_to_key(char *compound_key, void *key,
+			      struct hist_field *key_field, void *rec)
+{
+	size_t size = key_field->size;
+
+	if (key_field->flags & HIST_FIELD_FL_STRING) {
+		struct ftrace_event_field *field;
+
+		field = key_field->field;
+		if (field->filter_type == FILTER_DYN_STRING)
+			size = *(u32 *)(rec + field->offset) >> 16;
+		else if (field->filter_type == FILTER_PTR_STRING)
+			size = strlen(key);
+		else if (field->filter_type == FILTER_STATIC_STRING)
+			size = field->size;
+
+		/* ensure NULL-termination */
+		if (size > key_field->size - 1)
+			size = key_field->size - 1;
+	}
+
+	memcpy(compound_key + key_field->offset, key, size);
+}
+
+static void event_hist_trigger(struct event_trigger_data *data, void *rec)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+	bool use_compound_key = (hist_data->n_keys > 1);
+	unsigned long entries[HIST_STACKTRACE_DEPTH];
+	char compound_key[HIST_KEY_SIZE_MAX];
+	struct stack_trace stacktrace;
+	struct hist_field *key_field;
+	struct tracing_map_elt *elt;
+	u64 field_contents;
+	void *key = NULL;
+	unsigned int i;
+
+	memset(compound_key, 0, hist_data->key_size);
+
+	for_each_hist_key_field(i, hist_data) {
+		key_field = hist_data->fields[i];
+
+		if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
+			stacktrace.max_entries = HIST_STACKTRACE_DEPTH;
+			stacktrace.entries = entries;
+			stacktrace.nr_entries = 0;
+			stacktrace.skip = HIST_STACKTRACE_SKIP;
+
+			memset(stacktrace.entries, 0, HIST_STACKTRACE_SIZE);
+			save_stack_trace(&stacktrace);
+
+			key = entries;
+		} else {
+			field_contents = key_field->fn(key_field, rec);
+			if (key_field->flags & HIST_FIELD_FL_STRING) {
+				key = (void *)(unsigned long)field_contents;
+				use_compound_key = true;
+			} else
+				key = (void *)&field_contents;
+		}
+
+		if (use_compound_key)
+			add_to_key(compound_key, key, key_field, rec);
+	}
+
+	if (use_compound_key)
+		key = compound_key;
+
+	elt = tracing_map_insert(hist_data->map, key);
+	if (elt)
+		hist_trigger_elt_update(hist_data, elt, rec);
+}
+
+static void hist_trigger_stacktrace_print(struct seq_file *m,
+					  unsigned long *stacktrace_entries,
+					  unsigned int max_entries)
+{
+	char str[KSYM_SYMBOL_LEN];
+	unsigned int spaces = 8;
+	unsigned int i;
+
+	for (i = 0; i < max_entries; i++) {
+		if (stacktrace_entries[i] == ULONG_MAX)
+			return;
+
+		seq_printf(m, "%*c", 1 + spaces, ' ');
+		sprint_symbol(str, stacktrace_entries[i]);
+		seq_printf(m, "%s\n", str);
+	}
+}
+
+static void
+hist_trigger_entry_print(struct seq_file *m,
+			 struct hist_trigger_data *hist_data, void *key,
+			 struct tracing_map_elt *elt)
+{
+	struct hist_field *key_field;
+	char str[KSYM_SYMBOL_LEN];
+	bool multiline = false;
+	unsigned int i;
+	u64 uval;
+
+	seq_puts(m, "{ ");
+
+	for_each_hist_key_field(i, hist_data) {
+		key_field = hist_data->fields[i];
+
+		if (i > hist_data->n_vals)
+			seq_puts(m, ", ");
+
+		if (key_field->flags & HIST_FIELD_FL_HEX) {
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: %llx",
+				   key_field->field->name, uval);
+		} else if (key_field->flags & HIST_FIELD_FL_SYM) {
+			uval = *(u64 *)(key + key_field->offset);
+			sprint_symbol_no_offset(str, uval);
+			seq_printf(m, "%s: [%llx] %-45s",
+				   key_field->field->name, uval, str);
+		} else if (key_field->flags & HIST_FIELD_FL_SYM_OFFSET) {
+			uval = *(u64 *)(key + key_field->offset);
+			sprint_symbol(str, uval);
+			seq_printf(m, "%s: [%llx] %-55s",
+				   key_field->field->name, uval, str);
+		} else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
+			char *comm = elt->private_data;
+
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: %-16s[%10llu]",
+				   key_field->field->name, comm, uval);
+		} else if (key_field->flags & HIST_FIELD_FL_SYSCALL) {
+			const char *syscall_name;
+
+			uval = *(u64 *)(key + key_field->offset);
+			syscall_name = get_syscall_name(uval);
+			if (!syscall_name)
+				syscall_name = "unknown_syscall";
+
+			seq_printf(m, "%s: %-30s[%3llu]",
+				   key_field->field->name, syscall_name, uval);
+		} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
+			seq_puts(m, "stacktrace:\n");
+			hist_trigger_stacktrace_print(m,
+						      key + key_field->offset,
+						      HIST_STACKTRACE_DEPTH);
+			multiline = true;
+		} else if (key_field->flags & HIST_FIELD_FL_LOG2) {
+			seq_printf(m, "%s: ~ 2^%-2llu", key_field->field->name,
+				   *(u64 *)(key + key_field->offset));
+		} else if (key_field->flags & HIST_FIELD_FL_STRING) {
+			seq_printf(m, "%s: %-50s", key_field->field->name,
+				   (char *)(key + key_field->offset));
+		} else {
+			uval = *(u64 *)(key + key_field->offset);
+			seq_printf(m, "%s: %10llu", key_field->field->name,
+				   uval);
+		}
+	}
+
+	if (!multiline)
+		seq_puts(m, " ");
+
+	seq_puts(m, "}");
+
+	seq_printf(m, " hitcount: %10llu",
+		   tracing_map_read_sum(elt, HITCOUNT_IDX));
+
+	for (i = 1; i < hist_data->n_vals; i++) {
+		if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) {
+			seq_printf(m, "  %s: %10llx",
+				   hist_data->fields[i]->field->name,
+				   tracing_map_read_sum(elt, i));
+		} else {
+			seq_printf(m, "  %s: %10llu",
+				   hist_data->fields[i]->field->name,
+				   tracing_map_read_sum(elt, i));
+		}
+	}
+
+	seq_puts(m, "\n");
+}
+
+static int print_entries(struct seq_file *m,
+			 struct hist_trigger_data *hist_data)
+{
+	struct tracing_map_sort_entry **sort_entries = NULL;
+	struct tracing_map *map = hist_data->map;
+	int i, n_entries;
+
+	n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
+					     hist_data->n_sort_keys,
+					     &sort_entries);
+	if (n_entries < 0)
+		return n_entries;
+
+	for (i = 0; i < n_entries; i++)
+		hist_trigger_entry_print(m, hist_data,
+					 sort_entries[i]->key,
+					 sort_entries[i]->elt);
+
+	tracing_map_destroy_sort_entries(sort_entries, n_entries);
+
+	return n_entries;
+}
+
+static void hist_trigger_show(struct seq_file *m,
+			      struct event_trigger_data *data, int n)
+{
+	struct hist_trigger_data *hist_data;
+	int n_entries, ret = 0;
+
+	if (n > 0)
+		seq_puts(m, "\n\n");
+
+	seq_puts(m, "# event histogram\n#\n# trigger info: ");
+	data->ops->print(m, data->ops, data);
+	seq_puts(m, "#\n\n");
+
+	hist_data = data->private_data;
+	n_entries = print_entries(m, hist_data);
+	if (n_entries < 0) {
+		ret = n_entries;
+		n_entries = 0;
+	}
+
+	seq_printf(m, "\nTotals:\n    Hits: %llu\n    Entries: %u\n    Dropped: %llu\n",
+		   (u64)atomic64_read(&hist_data->map->hits),
+		   n_entries, (u64)atomic64_read(&hist_data->map->drops));
+}
+
+static int hist_show(struct seq_file *m, void *v)
+{
+	struct event_trigger_data *data;
+	struct trace_event_file *event_file;
+	int n = 0, ret = 0;
+
+	mutex_lock(&event_mutex);
+
+	event_file = event_file_data(m->private);
+	if (unlikely(!event_file)) {
+		ret = -ENODEV;
+		goto out_unlock;
+	}
+
+	list_for_each_entry_rcu(data, &event_file->triggers, list) {
+		if (data->cmd_ops->trigger_type == ETT_EVENT_HIST)
+			hist_trigger_show(m, data, n++);
+	}
+
+ out_unlock:
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+static int event_hist_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, hist_show, file);
+}
+
+const struct file_operations event_hist_fops = {
+	.open = event_hist_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static const char *get_hist_field_flags(struct hist_field *hist_field)
+{
+	const char *flags_str = NULL;
+
+	if (hist_field->flags & HIST_FIELD_FL_HEX)
+		flags_str = "hex";
+	else if (hist_field->flags & HIST_FIELD_FL_SYM)
+		flags_str = "sym";
+	else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
+		flags_str = "sym-offset";
+	else if (hist_field->flags & HIST_FIELD_FL_EXECNAME)
+		flags_str = "execname";
+	else if (hist_field->flags & HIST_FIELD_FL_SYSCALL)
+		flags_str = "syscall";
+	else if (hist_field->flags & HIST_FIELD_FL_LOG2)
+		flags_str = "log2";
+
+	return flags_str;
+}
+
+static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
+{
+	seq_printf(m, "%s", hist_field->field->name);
+	if (hist_field->flags) {
+		const char *flags_str = get_hist_field_flags(hist_field);
+
+		if (flags_str)
+			seq_printf(m, ".%s", flags_str);
+	}
+}
+
+static int event_hist_trigger_print(struct seq_file *m,
+				    struct event_trigger_ops *ops,
+				    struct event_trigger_data *data)
+{
+	struct hist_trigger_data *hist_data = data->private_data;
+	struct hist_field *key_field;
+	unsigned int i;
+
+	seq_puts(m, "hist:");
+
+	if (data->name)
+		seq_printf(m, "%s:", data->name);
+
+	seq_puts(m, "keys=");
+
+	for_each_hist_key_field(i, hist_data) {
+		key_field = hist_data->fields[i];
+
+		if (i > hist_data->n_vals)
+			seq_puts(m, ",");
+
+		if (key_field->flags & HIST_FIELD_FL_STACKTRACE)
+			seq_puts(m, "stacktrace");
+		else
+			hist_field_print(m, key_field);
+	}
+
+	seq_puts(m, ":vals=");
+
+	for_each_hist_val_field(i, hist_data) {
+		if (i == HITCOUNT_IDX)
+			seq_puts(m, "hitcount");
+		else {
+			seq_puts(m, ",");
+			hist_field_print(m, hist_data->fields[i]);
+		}
+	}
+
+	seq_puts(m, ":sort=");
+
+	for (i = 0; i < hist_data->n_sort_keys; i++) {
+		struct tracing_map_sort_key *sort_key;