path: root/kernel/bpf/arraymap.c

// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
 * Copyright (c) 2016,2017 Facebook
 */
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/filter.h>
#include <linux/perf_event.h>
#include <uapi/linux/btf.h>
#include <linux/rcupdate_trace.h>

#include "map_in_map.h"

#define ARRAY_CREATE_FLAG_MASK \
	(BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
	 BPF_F_PRESERVE_ELEMS)

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 */
int array_map_alloc_check(union bpf_attr *attr)
{
	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
	int numa_node = bpf_map_attr_numa_node(attr);

	/* check sanity of attributes */
	if (attr->max_entries == 0 || attr->key_size != 4 ||
	    attr->value_size == 0 ||
	    attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
	    !bpf_map_flags_access_ok(attr->map_flags) ||
	    (percpu && numa_node != NUMA_NO_NODE))
		return -EINVAL;

	if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
	    attr->map_flags & BPF_F_MMAPABLE)
		return -EINVAL;

	if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
	    attr->map_flags & BPF_F_PRESERVE_ELEMS)
		return -EINVAL;

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

	return 0;
}

static struct bpf_map *array_map_alloc(union bpf_attr *attr)
{
	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
	int ret, numa_node = bpf_map_attr_numa_node(attr);
	u32 elem_size, index_mask, max_entries;
	bool bypass_spec_v1 = bpf_bypass_spec_v1();
	u64 cost, array_size, mask64;
	struct bpf_map_memory mem;
	struct bpf_array *array;

	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