kernel/bpf/arraymap.c - kernel/common.git - 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/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]);
 		cond_resched();
 	}
 }

 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;
 		cond_resched();
 	}

 	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;
 	u32 elem_size, index_mask, max_entries;
 	bool unpriv = !capable(CAP_SYS_ADMIN);
 	u64 cost, array_size, mask64;
 	struct bpf_array *array;
 	int ret;

 	/* 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);

 	max_entries = attr->max_entries;

 	/* On 32 bit archs roundup_pow_of_two() with max_entries that has
 	 * upper most bit set in u32 space is undefined behavior due to
 	 * resulting 1U << 32, so do it manually here in u64 space.
 	 */
 	mask64 = fls_long(max_entries - 1);
 	mask64 = 1ULL << mask64;
 	mask64 -= 1;

 	index_mask = mask64;
 	if (unpriv) {
 		/* round up array size to nearest power of 2,
 		 * since cpu will speculate within index_mask limits
 		 */
 		max_entries = index_mask + 1;
 		/* Check for overflows. */
 		if (max_entries < attr->max_entries)
 			return ERR_PTR(-E2BIG);
 	}

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

 	/* make sure there is no u32 overflow later in round_up() */
 	cost = array_size;
 	if (cost >= U32_MAX - PAGE_SIZE)
 		return ERR_PTR(-ENOMEM);
 	if (percpu) {
 		cost += (u64)attr->max_entries * elem_size * num_possible_cpus();
 		if (cost >= U32_MAX - PAGE_SIZE)
 			return ERR_PTR(-ENOMEM);
 	}
 	cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;

 	ret = bpf_map_precharge_memlock(cost);
 	if (ret < 0)
 		return ERR_PTR(ret);

 	/* allocate all map elements and zero-initialize them */
 	array = bpf_map_area_alloc(array_size);
 	if (!array)
 		return ERR_PTR(-ENOMEM);
 	array->index_mask = index_mask;
 	array->map.unpriv_array = unpriv;

 	/* 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->map.map_flags = attr->map_flags;
 	array->map.pages = cost;
 	array->elem_size = elem_size;

 	if (percpu &&
 	    (elem_size > PCPU_MIN_UNIT_SIZE ||
 	     bpf_array_alloc_percpu(array))) {
 		bpf_map_area_free(array);
 		return ERR_PTR(-ENOMEM);
 	}

 	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 & array->index_mask);
 }

 /* 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 & array->index_mask]);
 }

 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 & array->index_mask];
 	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 = key ? *(u32 *)key : U32_MAX;
 	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 & array->index_mask]),
 		       value, map->value_size);
 	else
 		memcpy(array->value +
 		       array->elem_size * (index & array->index_mask),
 		       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 & array->index_mask];
 	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);

 	bpf_map_area_free(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);

 	bpf_map_area_free(array);
 }

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

 /* only called from syscall */
 int bpf_fd_array_map_update_elem(struct bpf_map *map, struct file *map_file,
 				 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, map_file, 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,
 				   struct file *map_file, 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)
 {
 	bpf_prog_put(ptr);
 }

 /* 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_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 struct bpf_event_entry *bpf_event_entry_gen(struct file *perf_file,
 						   struct file *map_file)
 {
 	struct bpf_event_entry *ee;

 	ee = kzalloc(sizeof(*ee), GFP_ATOMIC);
 	if (ee) {
 		ee->event = perf_file->private_data;
 		ee->perf_file = perf_file;
 		ee->map_file = map_file;
 	}

 	return ee;
 }

 static void __bpf_event_entry_free(struct rcu_head *rcu)
 {
 	struct bpf_event_entry *ee;

 	ee = container_of(rcu, struct bpf_event_entry, rcu);
 	fput(ee->perf_file);
 	kfree(ee);
 }

 static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
 {
 	call_rcu(&ee->rcu, __bpf_event_entry_free);
 }

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

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

 	event = perf_file->private_data;
 	ee = ERR_PTR(-EINVAL);

 	attr = perf_event_attrs(event);
 	if (IS_ERR(attr) || attr->inherit)
 		goto err_out;

 	switch (attr->type) {
 	case PERF_TYPE_SOFTWARE:
 		if (attr->config != PERF_COUNT_SW_BPF_OUTPUT)
 			goto err_out;
 		/* fall-through */
 	case PERF_TYPE_RAW:
 	case PERF_TYPE_HARDWARE:
 		ee = bpf_event_entry_gen(perf_file, map_file);
 		if (ee)
 			return ee;
 		ee = ERR_PTR(-ENOMEM);
 		/* fall-through */
 	default:
 		break;
 	}

 err_out:
 	fput(perf_file);
 	return ee;
 }

 static void perf_event_fd_array_put_ptr(void *ptr)
 {
 	bpf_event_entry_free_rcu(ptr);
 }

 static void perf_event_fd_array_release(struct bpf_map *map,
 					struct file *map_file)
 {
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
 	struct bpf_event_entry *ee;
 	int i;

 	rcu_read_lock();
 	for (i = 0; i < array->map.max_entries; i++) {
 		ee = READ_ONCE(array->ptrs[i]);
 		if (ee && ee->map_file == map_file)
 			fd_array_map_delete_elem(map, &i);
 	}
 	rcu_read_unlock();
 }

 static const struct bpf_map_ops perf_event_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_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,
 	.map_release = perf_event_fd_array_release,
 };

 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);

 #ifdef CONFIG_CGROUPS
 static void *cgroup_fd_array_get_ptr(struct bpf_map *map,
 				     struct file *map_file /* not used */,
 				     int fd)
 {
 	return cgroup_get_from_fd(fd);
 }

 static void cgroup_fd_array_put_ptr(void *ptr)
 {
 	/* cgroup_put free cgrp after a rcu grace period */
 	cgroup_put(ptr);
 }

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

 static const struct bpf_map_ops cgroup_array_ops = {
 	.map_alloc = fd_array_map_alloc,
 	.map_free = cgroup_fd_array_free,
 	.map_get_next_key = array_map_get_next_key,
 	.map_lookup_elem = fd_array_map_lookup_elem,
 	.map_delete_elem = fd_array_map_delete_elem,
 	.map_fd_get_ptr = cgroup_fd_array_get_ptr,
 	.map_fd_put_ptr = cgroup_fd_array_put_ptr,
 };

 static struct bpf_map_type_list cgroup_array_type __read_mostly = {
 	.ops = &cgroup_array_ops,
 	.type = BPF_MAP_TYPE_CGROUP_ARRAY,
 };

 static int __init register_cgroup_array_map(void)
 {
 	bpf_register_map_type(&cgroup_array_type);
 	return 0;
 }
 late_initcall(register_cgroup_array_map);
 #endif
	/* 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/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]);
	cond_resched();
	}
	}

	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;
	cond_resched();
	}

	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;
	u32 elem_size, index_mask, max_entries;
	bool unpriv = !capable(CAP_SYS_ADMIN);
	u64 cost, array_size, mask64;
	struct bpf_array *array;
	int ret;

	/* 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);

	max_entries = attr->max_entries;

	/* On 32 bit archs roundup_pow_of_two() with max_entries that has
	* upper most bit set in u32 space is undefined behavior due to
	* resulting 1U << 32, so do it manually here in u64 space.
	*/
	mask64 = fls_long(max_entries - 1);
	mask64 = 1ULL << mask64;
	mask64 -= 1;

	index_mask = mask64;
	if (unpriv) {
	/* round up array size to nearest power of 2,
	* since cpu will speculate within index_mask limits
	*/
	max_entries = index_mask + 1;
	/* Check for overflows. */
	if (max_entries < attr->max_entries)
	return ERR_PTR(-E2BIG);
	}

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

	/* make sure there is no u32 overflow later in round_up() */
	cost = array_size;
	if (cost >= U32_MAX - PAGE_SIZE)
	return ERR_PTR(-ENOMEM);
	if (percpu) {
	cost += (u64)attr->max_entries * elem_size * num_possible_cpus();
	if (cost >= U32_MAX - PAGE_SIZE)
	return ERR_PTR(-ENOMEM);
	}
	cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;

	ret = bpf_map_precharge_memlock(cost);
	if (ret < 0)
	return ERR_PTR(ret);

	/* allocate all map elements and zero-initialize them */
	array = bpf_map_area_alloc(array_size);
	if (!array)
	return ERR_PTR(-ENOMEM);
	array->index_mask = index_mask;
	array->map.unpriv_array = unpriv;

	/* 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->map.map_flags = attr->map_flags;
	array->map.pages = cost;
	array->elem_size = elem_size;

	if (percpu &&
	(elem_size > PCPU_MIN_UNIT_SIZE \|\|
	bpf_array_alloc_percpu(array))) {
	bpf_map_area_free(array);
	return ERR_PTR(-ENOMEM);
	}

	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 & array->index_mask);
	}

	/* 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 & array->index_mask]);
	}

	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 & array->index_mask];
	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 = key ? (u32 )key : U32_MAX;
	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 & array->index_mask]),
	value, map->value_size);
	else
	memcpy(array->value +
	array->elem_size * (index & array->index_mask),
	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 & array->index_mask];
	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);

	bpf_map_area_free(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);

	bpf_map_area_free(array);
	}

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

	/* only called from syscall */
	int bpf_fd_array_map_update_elem(struct bpf_map map, struct file map_file,
	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, map_file, 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,
	struct file *map_file, 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)
	{
	bpf_prog_put(ptr);
	}

	/* 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_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 struct bpf_event_entry bpf_event_entry_gen(struct file perf_file,
	struct file *map_file)
	{
	struct bpf_event_entry *ee;

	ee = kzalloc(sizeof(*ee), GFP_ATOMIC);
	if (ee) {
	ee->event = perf_file->private_data;
	ee->perf_file = perf_file;
	ee->map_file = map_file;
	}

	return ee;
	}

	static void __bpf_event_entry_free(struct rcu_head *rcu)
	{
	struct bpf_event_entry *ee;

	ee = container_of(rcu, struct bpf_event_entry, rcu);
	fput(ee->perf_file);
	kfree(ee);
	}

	static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
	{
	call_rcu(&ee->rcu, __bpf_event_entry_free);
	}

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

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

	event = perf_file->private_data;
	ee = ERR_PTR(-EINVAL);

	attr = perf_event_attrs(event);
	if (IS_ERR(attr) \|\| attr->inherit)
	goto err_out;

	switch (attr->type) {
	case PERF_TYPE_SOFTWARE:
	if (attr->config != PERF_COUNT_SW_BPF_OUTPUT)
	goto err_out;
	/* fall-through */
	case PERF_TYPE_RAW:
	case PERF_TYPE_HARDWARE:
	ee = bpf_event_entry_gen(perf_file, map_file);
	if (ee)
	return ee;
	ee = ERR_PTR(-ENOMEM);
	/* fall-through */
	default:
	break;
	}

	err_out:
	fput(perf_file);
	return ee;
	}

	static void perf_event_fd_array_put_ptr(void *ptr)
	{
	bpf_event_entry_free_rcu(ptr);
	}

	static void perf_event_fd_array_release(struct bpf_map *map,
	struct file *map_file)
	{
	struct bpf_array *array = container_of(map, struct bpf_array, map);
	struct bpf_event_entry *ee;
	int i;

	rcu_read_lock();
	for (i = 0; i < array->map.max_entries; i++) {
	ee = READ_ONCE(array->ptrs[i]);
	if (ee && ee->map_file == map_file)
	fd_array_map_delete_elem(map, &i);
	}
	rcu_read_unlock();
	}

	static const struct bpf_map_ops perf_event_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_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,
	.map_release = perf_event_fd_array_release,
	};

	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);

	#ifdef CONFIG_CGROUPS
	static void cgroup_fd_array_get_ptr(struct bpf_map map,
	struct file map_file / not used */,
	int fd)
	{
	return cgroup_get_from_fd(fd);
	}

	static void cgroup_fd_array_put_ptr(void *ptr)
	{
	/* cgroup_put free cgrp after a rcu grace period */
	cgroup_put(ptr);
	}

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

	static const struct bpf_map_ops cgroup_array_ops = {
	.map_alloc = fd_array_map_alloc,
	.map_free = cgroup_fd_array_free,
	.map_get_next_key = array_map_get_next_key,
	.map_lookup_elem = fd_array_map_lookup_elem,
	.map_delete_elem = fd_array_map_delete_elem,
	.map_fd_get_ptr = cgroup_fd_array_get_ptr,
	.map_fd_put_ptr = cgroup_fd_array_put_ptr,
	};

	static struct bpf_map_type_list cgroup_array_type __read_mostly = {
	.ops = &cgroup_array_ops,
	.type = BPF_MAP_TYPE_CGROUP_ARRAY,
	};

	static int __init register_cgroup_array_map(void)
	{
	bpf_register_map_type(&cgroup_array_type);
	return 0;
	}
	late_initcall(register_cgroup_array_map);
	#endif