kernel/bpf/arraymap.c - linux - Git at Google

 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of version 2 of the GNU General Public
  * License as published by the Free Software Foundation.
  *
  * 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.
  */
 #include <linux/bpf.h>
 #include <linux/err.h>
 #include <linux/vmalloc.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
 #include <linux/filter.h>
 #include <linux/perf_event.h>

 static void bpf_array_free_percpu(struct bpf_array *array)
 {
 	int i;

 	for (i = 0; i < array->map.max_entries; i++)
 		free_percpu(array->pptrs[i]);
 }

 static int bpf_array_alloc_percpu(struct bpf_array *array)
 {
 	void __percpu *ptr;
 	int i;

 	for (i = 0; i < array->map.max_entries; i++) {
 		ptr = __alloc_percpu_gfp(array->elem_size, 8,
 					 GFP_USER | __GFP_NOWARN);
 		if (!ptr) {
 			bpf_array_free_percpu(array);
 			return -ENOMEM;
 		}
 		array->pptrs[i] = ptr;
 	}

 	return 0;
 }

 /* Called from syscall */
 static struct bpf_map *array_map_alloc(union bpf_attr *attr)
 {
 	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
 	struct bpf_array *array;
 	u64 array_size;
 	u32 elem_size;

 	/* check sanity of attributes */
 	if (attr->max_entries == 0 || attr->key_size != 4 ||
 	    attr->value_size == 0 || attr->map_flags)
 		return ERR_PTR(-EINVAL);

 	if (attr->value_size >= 1 << (KMALLOC_SHIFT_MAX - 1))
 		/* if value_size is bigger, the user space won't be able to
 		 * access the elements.
 		 */
 		return ERR_PTR(-E2BIG);

 	elem_size = round_up(attr->value_size, 8);

 	array_size = sizeof(*array);
 	if (percpu)
 		array_size += (u64) attr->max_entries * sizeof(void *);
 	else
 		array_size += (u64) attr->max_entries * elem_size;

 	/* make sure there is no u32 overflow later in round_up() */
 	if (array_size >= U32_MAX - PAGE_SIZE)
 		return ERR_PTR(-ENOMEM);


 	/* allocate all map elements and zero-initialize them */
 	array = kzalloc(array_size, GFP_USER | __GFP_NOWARN);
 	if (!array) {
 		array = vzalloc(array_size);
 		if (!array)
 			return ERR_PTR(-ENOMEM);
 	}

 	/* copy mandatory map attributes */
 	array->map.map_type = attr->map_type;
 	array->map.key_size = attr->key_size;
 	array->map.value_size = attr->value_size;
 	array->map.max_entries = attr->max_entries;
 	array->elem_size = elem_size;

 	if (!percpu)
 		goto out;

 	array_size += (u64) attr->max_entries * elem_size * num_possible_cpus();

 	if (array_size >= U32_MAX - PAGE_SIZE ||
 	    elem_size > PCPU_MIN_UNIT_SIZE || bpf_array_alloc_percpu(array)) {
 		kvfree(array);
 		return ERR_PTR(-ENOMEM);
 	}
 out:
 	array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;

 	return &array->map;
 }

 /* Called from syscall or from eBPF program */
 static void *array_map_lookup_elem(struct bpf_map *map, void *key)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	u32 index = *(u32 *)key;

 	if (unlikely(index >= array->map.max_entries))
 		return NULL;

 	return array->value + array->elem_size * index;
 }

 /* Called from eBPF program */
 static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	u32 index = *(u32 *)key;

 	if (unlikely(index >= array->map.max_entries))
 		return NULL;

 	return this_cpu_ptr(array->pptrs[index]);
 }

 int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	u32 index = *(u32 *)key;
 	void __percpu *pptr;
 	int cpu, off = 0;
 	u32 size;

 	if (unlikely(index >= array->map.max_entries))
 		return -ENOENT;

 	/* per_cpu areas are zero-filled and bpf programs can only
 	 * access 'value_size' of them, so copying rounded areas
 	 * will not leak any kernel data
 	 */
 	size = round_up(map->value_size, 8);
 	rcu_read_lock();
 	pptr = array->pptrs[index];
 	for_each_possible_cpu(cpu) {
 		bpf_long_memcpy(value + off, per_cpu_ptr(pptr, cpu), size);
 		off += size;
 	}
 	rcu_read_unlock();
 	return 0;
 }

 /* Called from syscall */
 static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	u32 index = *(u32 *)key;
 	u32 *next = (u32 *)next_key;

 	if (index >= array->map.max_entries) {
 		*next = 0;
 		return 0;
 	}

 	if (index == array->map.max_entries - 1)
 		return -ENOENT;

 	*next = index + 1;
 	return 0;
 }

 /* Called from syscall or from eBPF program */
 static int array_map_update_elem(struct bpf_map *map, void *key, void *value,
 				 u64 map_flags)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	u32 index = *(u32 *)key;

 	if (unlikely(map_flags > BPF_EXIST))
 		/* unknown flags */
 		return -EINVAL;

 	if (unlikely(index >= array->map.max_entries))
 		/* all elements were pre-allocated, cannot insert a new one */
 		return -E2BIG;

 	if (unlikely(map_flags == BPF_NOEXIST))
 		/* all elements already exist */
 		return -EEXIST;

 	if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
 		memcpy(this_cpu_ptr(array->pptrs[index]),
 		       value, map->value_size);
 	else
 		memcpy(array->value + array->elem_size * index,
 		       value, map->value_size);
 	return 0;
 }

 int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
 			    u64 map_flags)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	u32 index = *(u32 *)key;
 	void __percpu *pptr;
 	int cpu, off = 0;
 	u32 size;

 	if (unlikely(map_flags > BPF_EXIST))
 		/* unknown flags */
 		return -EINVAL;

 	if (unlikely(index >= array->map.max_entries))
 		/* all elements were pre-allocated, cannot insert a new one */
 		return -E2BIG;

 	if (unlikely(map_flags == BPF_NOEXIST))
 		/* all elements already exist */
 		return -EEXIST;

 	/* the user space will provide round_up(value_size, 8) bytes that
 	 * will be copied into per-cpu area. bpf programs can only access
 	 * value_size of it. During lookup the same extra bytes will be
 	 * returned or zeros which were zero-filled by percpu_alloc,
 	 * so no kernel data leaks possible
 	 */
 	size = round_up(map->value_size, 8);
 	rcu_read_lock();
 	pptr = array->pptrs[index];
 	for_each_possible_cpu(cpu) {
 		bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value + off, size);
 		off += size;
 	}
 	rcu_read_unlock();
 	return 0;
 }

 /* Called from syscall or from eBPF program */
 static int array_map_delete_elem(struct bpf_map *map, void *key)
 {
 	return -EINVAL;
 }

 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
 static void array_map_free(struct bpf_map *map)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);

 	/* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
 	 * so the programs (can be more than one that used this map) were
 	 * disconnected from events. Wait for outstanding programs to complete
 	 * and free the array
 	 */
 	synchronize_rcu();

 	if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
 		bpf_array_free_percpu(array);

 	kvfree(array);
 }

 static const struct bpf_map_ops array_ops = {
 	.map_alloc = array_map_alloc,
 	.map_free = array_map_free,
 	.map_get_next_key = array_map_get_next_key,
 	.map_lookup_elem = array_map_lookup_elem,
 	.map_update_elem = array_map_update_elem,
 	.map_delete_elem = array_map_delete_elem,
 };

 static struct bpf_map_type_list array_type __read_mostly = {
 	.ops = &array_ops,
 	.type = BPF_MAP_TYPE_ARRAY,
 };

 static const struct bpf_map_ops percpu_array_ops = {
 	.map_alloc = array_map_alloc,
 	.map_free = array_map_free,
 	.map_get_next_key = array_map_get_next_key,
 	.map_lookup_elem = percpu_array_map_lookup_elem,
 	.map_update_elem = array_map_update_elem,
 	.map_delete_elem = array_map_delete_elem,
 };

 static struct bpf_map_type_list percpu_array_type __read_mostly = {
 	.ops = &percpu_array_ops,
 	.type = BPF_MAP_TYPE_PERCPU_ARRAY,
 };

 static int __init register_array_map(void)
 {
 	bpf_register_map_type(&array_type);
 	bpf_register_map_type(&percpu_array_type);
 	return 0;
 }
 late_initcall(register_array_map);

 static struct bpf_map *fd_array_map_alloc(union bpf_attr *attr)
 {
 	/* only file descriptors can be stored in this type of map */
 	if (attr->value_size != sizeof(u32))
 		return ERR_PTR(-EINVAL);
 	return array_map_alloc(attr);
 }

 static void fd_array_map_free(struct bpf_map *map)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	int i;

 	synchronize_rcu();

 	/* make sure it's empty */
 	for (i = 0; i < array->map.max_entries; i++)
 		BUG_ON(array->ptrs[i] != NULL);
 	kvfree(array);
 }

 static void *fd_array_map_lookup_elem(struct bpf_map *map, void *key)
 {
 	return NULL;
 }

 /* only called from syscall */
 static int fd_array_map_update_elem(struct bpf_map *map, void *key,
 				    void *value, u64 map_flags)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	void *new_ptr, *old_ptr;
 	u32 index = *(u32 *)key, ufd;

 	if (map_flags != BPF_ANY)
 		return -EINVAL;

 	if (index >= array->map.max_entries)
 		return -E2BIG;

 	ufd = *(u32 *)value;
 	new_ptr = map->ops->map_fd_get_ptr(map, ufd);
 	if (IS_ERR(new_ptr))
 		return PTR_ERR(new_ptr);

 	old_ptr = xchg(array->ptrs + index, new_ptr);
 	if (old_ptr)
 		map->ops->map_fd_put_ptr(old_ptr);

 	return 0;
 }

 static int fd_array_map_delete_elem(struct bpf_map *map, void *key)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	void *old_ptr;
 	u32 index = *(u32 *)key;

 	if (index >= array->map.max_entries)
 		return -E2BIG;

 	old_ptr = xchg(array->ptrs + index, NULL);
 	if (old_ptr) {
 		map->ops->map_fd_put_ptr(old_ptr);
 		return 0;
 	} else {
 		return -ENOENT;
 	}
 }

 static void *prog_fd_array_get_ptr(struct bpf_map *map, int fd)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	struct bpf_prog *prog = bpf_prog_get(fd);
 	if (IS_ERR(prog))
 		return prog;

 	if (!bpf_prog_array_compatible(array, prog)) {
 		bpf_prog_put(prog);
 		return ERR_PTR(-EINVAL);
 	}
 	return prog;
 }

 static void prog_fd_array_put_ptr(void *ptr)
 {
 	struct bpf_prog *prog = ptr;

 	bpf_prog_put_rcu(prog);
 }

 /* decrement refcnt of all bpf_progs that are stored in this map */
 void bpf_fd_array_map_clear(struct bpf_map *map)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	int i;

 	for (i = 0; i < array->map.max_entries; i++)
 		fd_array_map_delete_elem(map, &i);
 }

 static const struct bpf_map_ops prog_array_ops = {
 	.map_alloc = fd_array_map_alloc,
 	.map_free = fd_array_map_free,
 	.map_get_next_key = array_map_get_next_key,
 	.map_lookup_elem = fd_array_map_lookup_elem,
 	.map_update_elem = fd_array_map_update_elem,
 	.map_delete_elem = fd_array_map_delete_elem,
 	.map_fd_get_ptr = prog_fd_array_get_ptr,
 	.map_fd_put_ptr = prog_fd_array_put_ptr,
 };

 static struct bpf_map_type_list prog_array_type __read_mostly = {
 	.ops = &prog_array_ops,
 	.type = BPF_MAP_TYPE_PROG_ARRAY,
 };

 static int __init register_prog_array_map(void)
 {
 	bpf_register_map_type(&prog_array_type);
 	return 0;
 }
 late_initcall(register_prog_array_map);

 static void perf_event_array_map_free(struct bpf_map *map)
 {
 	bpf_fd_array_map_clear(map);
 	fd_array_map_free(map);
 }

 static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd)
 {
 	struct perf_event *event;
 	const struct perf_event_attr *attr;
 	struct file *file;

 	file = perf_event_get(fd);
 	if (IS_ERR(file))
 		return file;

 	event = file->private_data;

 	attr = perf_event_attrs(event);
 	if (IS_ERR(attr))
 		goto err;

 	if (attr->inherit)
 		goto err;

 	if (attr->type == PERF_TYPE_RAW)
 		return file;

 	if (attr->type == PERF_TYPE_HARDWARE)
 		return file;

 	if (attr->type == PERF_TYPE_SOFTWARE &&
 	    attr->config == PERF_COUNT_SW_BPF_OUTPUT)
 		return file;
 err:
 	fput(file);
 	return ERR_PTR(-EINVAL);
 }

 static void perf_event_fd_array_put_ptr(void *ptr)
 {
 	fput((struct file *)ptr);
 }

 static const struct bpf_map_ops perf_event_array_ops = {
 	.map_alloc = fd_array_map_alloc,
 	.map_free = perf_event_array_map_free,
 	.map_get_next_key = array_map_get_next_key,
 	.map_lookup_elem = fd_array_map_lookup_elem,
 	.map_update_elem = fd_array_map_update_elem,
 	.map_delete_elem = fd_array_map_delete_elem,
 	.map_fd_get_ptr = perf_event_fd_array_get_ptr,
 	.map_fd_put_ptr = perf_event_fd_array_put_ptr,
 };

 static struct bpf_map_type_list perf_event_array_type __read_mostly = {
 	.ops = &perf_event_array_ops,
 	.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
 };

 static int __init register_perf_event_array_map(void)
 {
 	bpf_register_map_type(&perf_event_array_type);
 	return 0;
 }
 late_initcall(register_perf_event_array_map);
	/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of version 2 of the GNU General Public
	* License as published by the Free Software Foundation.
	*
	* 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.
	*/
	#include <linux/bpf.h>
	#include <linux/err.h>
	#include <linux/vmalloc.h>
	#include <linux/slab.h>
	#include <linux/mm.h>
	#include <linux/filter.h>
	#include <linux/perf_event.h>

	static void bpf_array_free_percpu(struct bpf_array *array)
	{
	int i;

	for (i = 0; i < array->map.max_entries; i++)
	free_percpu(array->pptrs[i]);
	}

	static int bpf_array_alloc_percpu(struct bpf_array *array)
	{
	void __percpu *ptr;
	int i;

	for (i = 0; i < array->map.max_entries; i++) {
	ptr = __alloc_percpu_gfp(array->elem_size, 8,
	GFP_USER \| __GFP_NOWARN);
	if (!ptr) {
	bpf_array_free_percpu(array);
	return -ENOMEM;
	}
	array->pptrs[i] = ptr;
	}

	return 0;
	}

	/* Called from syscall */
	static struct bpf_map array_map_alloc(union bpf_attr attr)
	{
	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
	struct bpf_array *array;
	u64 array_size;
	u32 elem_size;

	/* check sanity of attributes */
	if (attr->max_entries == 0 \|\| attr->key_size != 4 \|\|
	attr->value_size == 0 \|\| attr->map_flags)
	return ERR_PTR(-EINVAL);

	if (attr->value_size >= 1 << (KMALLOC_SHIFT_MAX - 1))
	/* if value_size is bigger, the user space won't be able to
	* access the elements.
	*/
	return ERR_PTR(-E2BIG);

	elem_size = round_up(attr->value_size, 8);

	array_size = sizeof(*array);
	if (percpu)
	array_size += (u64) attr->max_entries * sizeof(void *);
	else
	array_size += (u64) attr->max_entries * elem_size;

	/* make sure there is no u32 overflow later in round_up() */
	if (array_size >= U32_MAX - PAGE_SIZE)
	return ERR_PTR(-ENOMEM);


	/* allocate all map elements and zero-initialize them */
	array = kzalloc(array_size, GFP_USER \| __GFP_NOWARN);
	if (!array) {
	array = vzalloc(array_size);
	if (!array)
	return ERR_PTR(-ENOMEM);
	}

	/* copy mandatory map attributes */
	array->map.map_type = attr->map_type;
	array->map.key_size = attr->key_size;
	array->map.value_size = attr->value_size;
	array->map.max_entries = attr->max_entries;
	array->elem_size = elem_size;

	if (!percpu)
	goto out;

	array_size += (u64) attr->max_entries * elem_size * num_possible_cpus();

	if (array_size >= U32_MAX - PAGE_SIZE \|\|
	elem_size > PCPU_MIN_UNIT_SIZE \|\| bpf_array_alloc_percpu(array)) {
	kvfree(array);
	return ERR_PTR(-ENOMEM);
	}
	out:
	array->map.pages = round_up(array_size, PAGE_SIZE) >> PAGE_SHIFT;

	return &array->map;
	}

	/* Called from syscall or from eBPF program */
	static void array_map_lookup_elem(struct bpf_map map, void *key)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	u32 index = (u32 )key;

	if (unlikely(index >= array->map.max_entries))
	return NULL;

	return array->value + array->elem_size * index;
	}

	/* Called from eBPF program */
	static void percpu_array_map_lookup_elem(struct bpf_map map, void *key)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	u32 index = (u32 )key;

	if (unlikely(index >= array->map.max_entries))
	return NULL;

	return this_cpu_ptr(array->pptrs[index]);
	}

	int bpf_percpu_array_copy(struct bpf_map map, void key, void *value)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	u32 index = (u32 )key;
	void __percpu *pptr;
	int cpu, off = 0;
	u32 size;

	if (unlikely(index >= array->map.max_entries))
	return -ENOENT;

	/* per_cpu areas are zero-filled and bpf programs can only
	* access 'value_size' of them, so copying rounded areas
	* will not leak any kernel data
	*/
	size = round_up(map->value_size, 8);
	rcu_read_lock();
	pptr = array->pptrs[index];
	for_each_possible_cpu(cpu) {
	bpf_long_memcpy(value + off, per_cpu_ptr(pptr, cpu), size);
	off += size;
	}
	rcu_read_unlock();
	return 0;
	}

	/* Called from syscall */
	static int array_map_get_next_key(struct bpf_map map, void key, void *next_key)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	u32 index = (u32 )key;
	u32 next = (u32 )next_key;

	if (index >= array->map.max_entries) {
	*next = 0;
	return 0;
	}

	if (index == array->map.max_entries - 1)
	return -ENOENT;

	*next = index + 1;
	return 0;
	}

	/* Called from syscall or from eBPF program */
	static int array_map_update_elem(struct bpf_map map, void key, void *value,
	u64 map_flags)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	u32 index = (u32 )key;

	if (unlikely(map_flags > BPF_EXIST))
	/* unknown flags */
	return -EINVAL;

	if (unlikely(index >= array->map.max_entries))
	/* all elements were pre-allocated, cannot insert a new one */
	return -E2BIG;

	if (unlikely(map_flags == BPF_NOEXIST))
	/* all elements already exist */
	return -EEXIST;

	if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
	memcpy(this_cpu_ptr(array->pptrs[index]),
	value, map->value_size);
	else
	memcpy(array->value + array->elem_size * index,
	value, map->value_size);
	return 0;
	}

	int bpf_percpu_array_update(struct bpf_map map, void key, void *value,
	u64 map_flags)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	u32 index = (u32 )key;
	void __percpu *pptr;
	int cpu, off = 0;
	u32 size;

	if (unlikely(map_flags > BPF_EXIST))
	/* unknown flags */
	return -EINVAL;

	if (unlikely(index >= array->map.max_entries))
	/* all elements were pre-allocated, cannot insert a new one */
	return -E2BIG;

	if (unlikely(map_flags == BPF_NOEXIST))
	/* all elements already exist */
	return -EEXIST;

	/* the user space will provide round_up(value_size, 8) bytes that
	* will be copied into per-cpu area. bpf programs can only access
	* value_size of it. During lookup the same extra bytes will be
	* returned or zeros which were zero-filled by percpu_alloc,
	* so no kernel data leaks possible
	*/
	size = round_up(map->value_size, 8);
	rcu_read_lock();
	pptr = array->pptrs[index];
	for_each_possible_cpu(cpu) {
	bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value + off, size);
	off += size;
	}
	rcu_read_unlock();
	return 0;
	}

	/* Called from syscall or from eBPF program */
	static int array_map_delete_elem(struct bpf_map map, void key)
	{
	return -EINVAL;
	}

	/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
	static void array_map_free(struct bpf_map *map)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);

	/* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
	* so the programs (can be more than one that used this map) were
	* disconnected from events. Wait for outstanding programs to complete
	* and free the array
	*/
	synchronize_rcu();

	if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
	bpf_array_free_percpu(array);

	kvfree(array);
	}

	static const struct bpf_map_ops array_ops = {
	.map_alloc = array_map_alloc,
	.map_free = array_map_free,
	.map_get_next_key = array_map_get_next_key,
	.map_lookup_elem = array_map_lookup_elem,
	.map_update_elem = array_map_update_elem,
	.map_delete_elem = array_map_delete_elem,
	};

	static struct bpf_map_type_list array_type __read_mostly = {
	.ops = &array_ops,
	.type = BPF_MAP_TYPE_ARRAY,
	};

	static const struct bpf_map_ops percpu_array_ops = {
	.map_alloc = array_map_alloc,
	.map_free = array_map_free,
	.map_get_next_key = array_map_get_next_key,
	.map_lookup_elem = percpu_array_map_lookup_elem,
	.map_update_elem = array_map_update_elem,
	.map_delete_elem = array_map_delete_elem,
	};

	static struct bpf_map_type_list percpu_array_type __read_mostly = {
	.ops = &percpu_array_ops,
	.type = BPF_MAP_TYPE_PERCPU_ARRAY,
	};

	static int __init register_array_map(void)
	{
	bpf_register_map_type(&array_type);
	bpf_register_map_type(&percpu_array_type);
	return 0;
	}
	late_initcall(register_array_map);

	static struct bpf_map fd_array_map_alloc(union bpf_attr attr)
	{
	/* only file descriptors can be stored in this type of map */
	if (attr->value_size != sizeof(u32))
	return ERR_PTR(-EINVAL);
	return array_map_alloc(attr);
	}

	static void fd_array_map_free(struct bpf_map *map)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	int i;

	synchronize_rcu();

	/* make sure it's empty */
	for (i = 0; i < array->map.max_entries; i++)
	BUG_ON(array->ptrs[i] != NULL);
	kvfree(array);
	}

	static void fd_array_map_lookup_elem(struct bpf_map map, void *key)
	{
	return NULL;
	}

	/* only called from syscall */
	static int fd_array_map_update_elem(struct bpf_map map, void key,
	void *value, u64 map_flags)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	void new_ptr, old_ptr;
	u32 index = (u32 )key, ufd;

	if (map_flags != BPF_ANY)
	return -EINVAL;

	if (index >= array->map.max_entries)
	return -E2BIG;

	ufd = (u32 )value;
	new_ptr = map->ops->map_fd_get_ptr(map, ufd);
	if (IS_ERR(new_ptr))
	return PTR_ERR(new_ptr);

	old_ptr = xchg(array->ptrs + index, new_ptr);
	if (old_ptr)
	map->ops->map_fd_put_ptr(old_ptr);

	return 0;
	}

	static int fd_array_map_delete_elem(struct bpf_map map, void key)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	void *old_ptr;
	u32 index = (u32 )key;

	if (index >= array->map.max_entries)
	return -E2BIG;

	old_ptr = xchg(array->ptrs + index, NULL);
	if (old_ptr) {
	map->ops->map_fd_put_ptr(old_ptr);
	return 0;
	} else {
	return -ENOENT;
	}
	}

	static void prog_fd_array_get_ptr(struct bpf_map map, int fd)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	struct bpf_prog *prog = bpf_prog_get(fd);
	if (IS_ERR(prog))
	return prog;

	if (!bpf_prog_array_compatible(array, prog)) {
	bpf_prog_put(prog);
	return ERR_PTR(-EINVAL);
	}
	return prog;
	}

	static void prog_fd_array_put_ptr(void *ptr)
	{
	struct bpf_prog *prog = ptr;

	bpf_prog_put_rcu(prog);
	}

	/* decrement refcnt of all bpf_progs that are stored in this map */
	void bpf_fd_array_map_clear(struct bpf_map *map)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	int i;

	for (i = 0; i < array->map.max_entries; i++)
	fd_array_map_delete_elem(map, &i);
	}

	static const struct bpf_map_ops prog_array_ops = {
	.map_alloc = fd_array_map_alloc,
	.map_free = fd_array_map_free,
	.map_get_next_key = array_map_get_next_key,
	.map_lookup_elem = fd_array_map_lookup_elem,
	.map_update_elem = fd_array_map_update_elem,
	.map_delete_elem = fd_array_map_delete_elem,
	.map_fd_get_ptr = prog_fd_array_get_ptr,
	.map_fd_put_ptr = prog_fd_array_put_ptr,
	};

	static struct bpf_map_type_list prog_array_type __read_mostly = {
	.ops = &prog_array_ops,
	.type = BPF_MAP_TYPE_PROG_ARRAY,
	};

	static int __init register_prog_array_map(void)
	{
	bpf_register_map_type(&prog_array_type);
	return 0;
	}
	late_initcall(register_prog_array_map);

	static void perf_event_array_map_free(struct bpf_map *map)
	{
	bpf_fd_array_map_clear(map);
	fd_array_map_free(map);
	}

	static void perf_event_fd_array_get_ptr(struct bpf_map map, int fd)
	{
	struct perf_event *event;
	const struct perf_event_attr *attr;
	struct file *file;

	file = perf_event_get(fd);
	if (IS_ERR(file))
	return file;

	event = file->private_data;

	attr = perf_event_attrs(event);
	if (IS_ERR(attr))
	goto err;

	if (attr->inherit)
	goto err;

	if (attr->type == PERF_TYPE_RAW)
	return file;

	if (attr->type == PERF_TYPE_HARDWARE)
	return file;

	if (attr->type == PERF_TYPE_SOFTWARE &&
	attr->config == PERF_COUNT_SW_BPF_OUTPUT)
	return file;
	err:
	fput(file);
	return ERR_PTR(-EINVAL);
	}

	static void perf_event_fd_array_put_ptr(void *ptr)
	{
	fput((struct file *)ptr);
	}

	static const struct bpf_map_ops perf_event_array_ops = {
	.map_alloc = fd_array_map_alloc,
	.map_free = perf_event_array_map_free,
	.map_get_next_key = array_map_get_next_key,
	.map_lookup_elem = fd_array_map_lookup_elem,
	.map_update_elem = fd_array_map_update_elem,
	.map_delete_elem = fd_array_map_delete_elem,
	.map_fd_get_ptr = perf_event_fd_array_get_ptr,
	.map_fd_put_ptr = perf_event_fd_array_put_ptr,
	};

	static struct bpf_map_type_list perf_event_array_type __read_mostly = {
	.ops = &perf_event_array_ops,
	.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
	};

	static int __init register_perf_event_array_map(void)
	{
	bpf_register_map_type(&perf_event_array_type);
	return 0;
	}
	late_initcall(register_perf_event_array_map);