// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
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* Copyright (c) 2016,2017 Facebook
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*/
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#include <linux/bpf.h>
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#include <linux/btf.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/filter.h>
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#include <linux/perf_event.h>
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#include <uapi/linux/btf.h>
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#include <linux/rcupdate_trace.h>
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#include "map_in_map.h"
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#define ARRAY_CREATE_FLAG_MASK \
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(BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \
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BPF_F_PRESERVE_ELEMS | BPF_F_INNER_MAP)
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static void bpf_array_free_percpu(struct bpf_array *array)
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{
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int i;
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for (i = 0; i < array->map.max_entries; i++) {
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free_percpu(array->pptrs[i]);
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cond_resched();
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}
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}
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static int bpf_array_alloc_percpu(struct bpf_array *array)
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{
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void __percpu *ptr;
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int i;
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for (i = 0; i < array->map.max_entries; i++) {
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ptr = __alloc_percpu_gfp(array->elem_size, 8,
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GFP_USER | __GFP_NOWARN);
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if (!ptr) {
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bpf_array_free_percpu(array);
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return -ENOMEM;
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}
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array->pptrs[i] = ptr;
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cond_resched();
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}
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return 0;
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}
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/* Called from syscall */
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int array_map_alloc_check(union bpf_attr *attr)
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{
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bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
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int numa_node = bpf_map_attr_numa_node(attr);
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/* check sanity of attributes */
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if (attr->max_entries == 0 || attr->key_size != 4 ||
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attr->value_size == 0 ||
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attr->map_flags & ~ARRAY_CREATE_FLAG_MASK ||
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!bpf_map_flags_access_ok(attr->map_flags) ||
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(percpu && numa_node != NUMA_NO_NODE))
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return -EINVAL;
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if (attr->map_type != BPF_MAP_TYPE_ARRAY &&
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attr->map_flags & (BPF_F_MMAPABLE | BPF_F_INNER_MAP))
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return -EINVAL;
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if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
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attr->map_flags & BPF_F_PRESERVE_ELEMS)
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return -EINVAL;
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if (attr->value_size > KMALLOC_MAX_SIZE)
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/* if value_size is bigger, the user space won't be able to
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* access the elements.
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*/
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return -E2BIG;
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return 0;
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}
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static struct bpf_map *array_map_alloc(union bpf_attr *attr)
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{
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bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
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int ret, numa_node = bpf_map_attr_numa_node(attr);
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u32 elem_size, index_mask, max_entries;
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bool bypass_spec_v1 = bpf_bypass_spec_v1();
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u64 cost, array_size, mask64;
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struct bpf_map_memory mem;
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struct bpf_array *array;
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elem_size = round_up(attr->value_size, 8);
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max_entries = attr->max_entries;
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/* On 32 bit archs roundup_pow_of_two() with max_entries that has
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* upper most bit set in u32 space is undefined behavior due to
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* resulting 1U << 32, so do it manually here in u64 space.
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*/
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mask64 = fls_long(max_entries - 1);
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mask64 = 1ULL << mask64;
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mask64 -= 1;
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index_mask = mask64;
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if (!bypass_spec_v1) {
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/* round up array size to nearest power of 2,
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* since cpu will speculate within index_mask limits
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*/
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max_entries = index_mask + 1;
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/* Check for overflows. */
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if (max_entries < attr->max_entries)
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return ERR_PTR(-E2BIG);
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}
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array_size = sizeof(*array);
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if (percpu) {
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array_size += (u64) max_entries * sizeof(void *);
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} else {
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/* rely on vmalloc() to return page-aligned memory and
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* ensure array->value is exactly page-aligned
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*/
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if (attr->map_flags & BPF_F_MMAPABLE) {
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array_size = PAGE_ALIGN(array_size);
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array_size += PAGE_ALIGN((u64) max_entries * elem_size);
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} else {
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array_size += (u64) max_entries * elem_size;
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}
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}
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/* make sure there is no u32 overflow later in round_up() */
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cost = array_size;
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if (percpu)
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cost += (u64)attr->max_entries * elem_size * num_possible_cpus();
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ret = bpf_map_charge_init(&mem, cost);
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if (ret < 0)
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return ERR_PTR(ret);
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/* allocate all map elements and zero-initialize them */
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if (attr->map_flags & BPF_F_MMAPABLE) {
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void *data;
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/* kmalloc'ed memory can't be mmap'ed, use explicit vmalloc */
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data = bpf_map_area_mmapable_alloc(array_size, numa_node);
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if (!data) {
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bpf_map_charge_finish(&mem);
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return ERR_PTR(-ENOMEM);
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}
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array = data + PAGE_ALIGN(sizeof(struct bpf_array))
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- offsetof(struct bpf_array, value);
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} else {
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array = bpf_map_area_alloc(array_size, numa_node);
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}
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if (!array) {
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bpf_map_charge_finish(&mem);
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return ERR_PTR(-ENOMEM);
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}
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array->index_mask = index_mask;
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array->map.bypass_spec_v1 = bypass_spec_v1;
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/* copy mandatory map attributes */
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bpf_map_init_from_attr(&array->map, attr);
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bpf_map_charge_move(&array->map.memory, &mem);
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array->elem_size = elem_size;
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if (percpu && bpf_array_alloc_percpu(array)) {
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bpf_map_charge_finish(&array->map.memory);
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bpf_map_area_free(array);
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return ERR_PTR(-ENOMEM);
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}
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return &array->map;
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}
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/* Called from syscall or from eBPF program */
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static void *array_map_lookup_elem(struct bpf_map *map, void *key)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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if (unlikely(index >= array->map.max_entries))
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return NULL;
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return array->value + array->elem_size * (index & array->index_mask);
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}
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static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
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u32 off)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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if (map->max_entries != 1)
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return -ENOTSUPP;
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if (off >= map->value_size)
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return -EINVAL;
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*imm = (unsigned long)array->value;
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return 0;
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}
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static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
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u32 *off)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u64 base = (unsigned long)array->value;
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u64 range = array->elem_size;
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if (map->max_entries != 1)
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return -ENOTSUPP;
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if (imm < base || imm >= base + range)
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return -ENOENT;
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*off = imm - base;
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return 0;
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}
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/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
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static int array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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struct bpf_insn *insn = insn_buf;
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u32 elem_size = round_up(map->value_size, 8);
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const int ret = BPF_REG_0;
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const int map_ptr = BPF_REG_1;
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const int index = BPF_REG_2;
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if (map->map_flags & BPF_F_INNER_MAP)
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return -EOPNOTSUPP;
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*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
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*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
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if (!map->bypass_spec_v1) {
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*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 4);
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*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
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} else {
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*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3);
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}
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if (is_power_of_2(elem_size)) {
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*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
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} else {
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*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
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}
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*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
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*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
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*insn++ = BPF_MOV64_IMM(ret, 0);
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return insn - insn_buf;
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}
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/* Called from eBPF program */
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static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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if (unlikely(index >= array->map.max_entries))
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return NULL;
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return this_cpu_ptr(array->pptrs[index & array->index_mask]);
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}
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int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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void __percpu *pptr;
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int cpu, off = 0;
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u32 size;
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if (unlikely(index >= array->map.max_entries))
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return -ENOENT;
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/* per_cpu areas are zero-filled and bpf programs can only
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* access 'value_size' of them, so copying rounded areas
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* will not leak any kernel data
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*/
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size = round_up(map->value_size, 8);
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rcu_read_lock();
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pptr = array->pptrs[index & array->index_mask];
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for_each_possible_cpu(cpu) {
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bpf_long_memcpy(value + off, per_cpu_ptr(pptr, cpu), size);
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off += size;
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}
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rcu_read_unlock();
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return 0;
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}
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/* Called from syscall */
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static int array_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = key ? *(u32 *)key : U32_MAX;
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u32 *next = (u32 *)next_key;
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if (index >= array->map.max_entries) {
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*next = 0;
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return 0;
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}
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if (index == array->map.max_entries - 1)
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return -ENOENT;
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*next = index + 1;
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return 0;
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}
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/* Called from syscall or from eBPF program */
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static int array_map_update_elem(struct bpf_map *map, void *key, void *value,
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u64 map_flags)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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char *val;
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if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST))
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/* unknown flags */
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return -EINVAL;
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if (unlikely(index >= array->map.max_entries))
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/* all elements were pre-allocated, cannot insert a new one */
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return -E2BIG;
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if (unlikely(map_flags & BPF_NOEXIST))
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/* all elements already exist */
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return -EEXIST;
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if (unlikely((map_flags & BPF_F_LOCK) &&
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!map_value_has_spin_lock(map)))
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return -EINVAL;
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if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
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memcpy(this_cpu_ptr(array->pptrs[index & array->index_mask]),
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value, map->value_size);
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} else {
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val = array->value +
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array->elem_size * (index & array->index_mask);
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if (map_flags & BPF_F_LOCK)
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copy_map_value_locked(map, val, value, false);
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else
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copy_map_value(map, val, value);
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}
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return 0;
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}
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int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
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u64 map_flags)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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void __percpu *pptr;
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int cpu, off = 0;
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u32 size;
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if (unlikely(map_flags > BPF_EXIST))
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/* unknown flags */
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return -EINVAL;
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if (unlikely(index >= array->map.max_entries))
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/* all elements were pre-allocated, cannot insert a new one */
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return -E2BIG;
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if (unlikely(map_flags == BPF_NOEXIST))
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/* all elements already exist */
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return -EEXIST;
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/* the user space will provide round_up(value_size, 8) bytes that
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* will be copied into per-cpu area. bpf programs can only access
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* value_size of it. During lookup the same extra bytes will be
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* returned or zeros which were zero-filled by percpu_alloc,
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* so no kernel data leaks possible
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*/
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size = round_up(map->value_size, 8);
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rcu_read_lock();
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pptr = array->pptrs[index & array->index_mask];
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for_each_possible_cpu(cpu) {
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bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value + off, size);
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off += size;
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}
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rcu_read_unlock();
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return 0;
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}
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/* Called from syscall or from eBPF program */
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static int array_map_delete_elem(struct bpf_map *map, void *key)
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{
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return -EINVAL;
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}
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static void *array_map_vmalloc_addr(struct bpf_array *array)
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{
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return (void *)round_down((unsigned long)array, PAGE_SIZE);
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}
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/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
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static void array_map_free(struct bpf_map *map)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
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bpf_array_free_percpu(array);
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if (array->map.map_flags & BPF_F_MMAPABLE)
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bpf_map_area_free(array_map_vmalloc_addr(array));
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else
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bpf_map_area_free(array);
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}
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static void array_map_seq_show_elem(struct bpf_map *map, void *key,
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struct seq_file *m)
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{
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void *value;
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rcu_read_lock();
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value = array_map_lookup_elem(map, key);
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if (!value) {
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rcu_read_unlock();
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return;
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}
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if (map->btf_key_type_id)
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seq_printf(m, "%u: ", *(u32 *)key);
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btf_type_seq_show(map->btf, map->btf_value_type_id, value, m);
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seq_puts(m, "\n");
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rcu_read_unlock();
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}
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static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
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struct seq_file *m)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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u32 index = *(u32 *)key;
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void __percpu *pptr;
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int cpu;
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rcu_read_lock();
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seq_printf(m, "%u: {\n", *(u32 *)key);
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pptr = array->pptrs[index & array->index_mask];
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for_each_possible_cpu(cpu) {
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seq_printf(m, "\tcpu%d: ", cpu);
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btf_type_seq_show(map->btf, map->btf_value_type_id,
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per_cpu_ptr(pptr, cpu), m);
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seq_puts(m, "\n");
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}
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seq_puts(m, "}\n");
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rcu_read_unlock();
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}
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static int array_map_check_btf(const struct bpf_map *map,
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const struct btf *btf,
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const struct btf_type *key_type,
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const struct btf_type *value_type)
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{
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u32 int_data;
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/* One exception for keyless BTF: .bss/.data/.rodata map */
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if (btf_type_is_void(key_type)) {
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if (map->map_type != BPF_MAP_TYPE_ARRAY ||
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map->max_entries != 1)
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return -EINVAL;
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if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC)
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return -EINVAL;
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return 0;
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}
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if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT)
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return -EINVAL;
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int_data = *(u32 *)(key_type + 1);
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/* bpf array can only take a u32 key. This check makes sure
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* that the btf matches the attr used during map_create.
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*/
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if (BTF_INT_BITS(int_data) != 32 || BTF_INT_OFFSET(int_data))
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return -EINVAL;
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return 0;
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}
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static int array_map_mmap(struct bpf_map *map, struct vm_area_struct *vma)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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pgoff_t pgoff = PAGE_ALIGN(sizeof(*array)) >> PAGE_SHIFT;
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if (!(map->map_flags & BPF_F_MMAPABLE))
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return -EINVAL;
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if (vma->vm_pgoff * PAGE_SIZE + (vma->vm_end - vma->vm_start) >
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PAGE_ALIGN((u64)array->map.max_entries * array->elem_size))
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return -EINVAL;
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return remap_vmalloc_range(vma, array_map_vmalloc_addr(array),
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vma->vm_pgoff + pgoff);
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}
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static bool array_map_meta_equal(const struct bpf_map *meta0,
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const struct bpf_map *meta1)
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{
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if (!bpf_map_meta_equal(meta0, meta1))
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return false;
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return meta0->map_flags & BPF_F_INNER_MAP ? true :
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meta0->max_entries == meta1->max_entries;
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}
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struct bpf_iter_seq_array_map_info {
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struct bpf_map *map;
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void *percpu_value_buf;
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u32 index;
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};
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static void *bpf_array_map_seq_start(struct seq_file *seq, loff_t *pos)
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{
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struct bpf_iter_seq_array_map_info *info = seq->private;
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struct bpf_map *map = info->map;
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struct bpf_array *array;
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u32 index;
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if (info->index >= map->max_entries)
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return NULL;
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if (*pos == 0)
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++*pos;
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array = container_of(map, struct bpf_array, map);
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index = info->index & array->index_mask;
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if (info->percpu_value_buf)
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return array->pptrs[index];
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return array->value + array->elem_size * index;
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}
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static void *bpf_array_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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{
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struct bpf_iter_seq_array_map_info *info = seq->private;
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struct bpf_map *map = info->map;
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struct bpf_array *array;
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u32 index;
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++*pos;
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++info->index;
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if (info->index >= map->max_entries)
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return NULL;
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array = container_of(map, struct bpf_array, map);
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index = info->index & array->index_mask;
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if (info->percpu_value_buf)
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return array->pptrs[index];
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return array->value + array->elem_size * index;
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}
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static int __bpf_array_map_seq_show(struct seq_file *seq, void *v)
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{
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struct bpf_iter_seq_array_map_info *info = seq->private;
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struct bpf_iter__bpf_map_elem ctx = {};
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struct bpf_map *map = info->map;
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struct bpf_iter_meta meta;
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struct bpf_prog *prog;
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int off = 0, cpu = 0;
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void __percpu **pptr;
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u32 size;
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meta.seq = seq;
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prog = bpf_iter_get_info(&meta, v == NULL);
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if (!prog)
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return 0;
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ctx.meta = &meta;
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ctx.map = info->map;
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if (v) {
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ctx.key = &info->index;
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if (!info->percpu_value_buf) {
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ctx.value = v;
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} else {
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pptr = v;
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size = round_up(map->value_size, 8);
|
for_each_possible_cpu(cpu) {
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bpf_long_memcpy(info->percpu_value_buf + off,
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per_cpu_ptr(pptr, cpu),
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size);
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off += size;
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}
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ctx.value = info->percpu_value_buf;
|
}
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}
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return bpf_iter_run_prog(prog, &ctx);
|
}
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static int bpf_array_map_seq_show(struct seq_file *seq, void *v)
|
{
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return __bpf_array_map_seq_show(seq, v);
|
}
|
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static void bpf_array_map_seq_stop(struct seq_file *seq, void *v)
|
{
|
if (!v)
|
(void)__bpf_array_map_seq_show(seq, NULL);
|
}
|
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static int bpf_iter_init_array_map(void *priv_data,
|
struct bpf_iter_aux_info *aux)
|
{
|
struct bpf_iter_seq_array_map_info *seq_info = priv_data;
|
struct bpf_map *map = aux->map;
|
void *value_buf;
|
u32 buf_size;
|
|
if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
|
buf_size = round_up(map->value_size, 8) * num_possible_cpus();
|
value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN);
|
if (!value_buf)
|
return -ENOMEM;
|
|
seq_info->percpu_value_buf = value_buf;
|
}
|
|
/* bpf_iter_attach_map() acquires a map uref, and the uref may be
|
* released before or in the middle of iterating map elements, so
|
* acquire an extra map uref for iterator.
|
*/
|
bpf_map_inc_with_uref(map);
|
seq_info->map = map;
|
return 0;
|
}
|
|
static void bpf_iter_fini_array_map(void *priv_data)
|
{
|
struct bpf_iter_seq_array_map_info *seq_info = priv_data;
|
|
bpf_map_put_with_uref(seq_info->map);
|
kfree(seq_info->percpu_value_buf);
|
}
|
|
static const struct seq_operations bpf_array_map_seq_ops = {
|
.start = bpf_array_map_seq_start,
|
.next = bpf_array_map_seq_next,
|
.stop = bpf_array_map_seq_stop,
|
.show = bpf_array_map_seq_show,
|
};
|
|
static const struct bpf_iter_seq_info iter_seq_info = {
|
.seq_ops = &bpf_array_map_seq_ops,
|
.init_seq_private = bpf_iter_init_array_map,
|
.fini_seq_private = bpf_iter_fini_array_map,
|
.seq_priv_size = sizeof(struct bpf_iter_seq_array_map_info),
|
};
|
|
static int array_map_btf_id;
|
const struct bpf_map_ops array_map_ops = {
|
.map_meta_equal = array_map_meta_equal,
|
.map_alloc_check = array_map_alloc_check,
|
.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,
|
.map_gen_lookup = array_map_gen_lookup,
|
.map_direct_value_addr = array_map_direct_value_addr,
|
.map_direct_value_meta = array_map_direct_value_meta,
|
.map_mmap = array_map_mmap,
|
.map_seq_show_elem = array_map_seq_show_elem,
|
.map_check_btf = array_map_check_btf,
|
.map_lookup_batch = generic_map_lookup_batch,
|
.map_update_batch = generic_map_update_batch,
|
.map_btf_name = "bpf_array",
|
.map_btf_id = &array_map_btf_id,
|
.iter_seq_info = &iter_seq_info,
|
};
|
|
static int percpu_array_map_btf_id;
|
const struct bpf_map_ops percpu_array_map_ops = {
|
.map_meta_equal = bpf_map_meta_equal,
|
.map_alloc_check = array_map_alloc_check,
|
.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,
|
.map_seq_show_elem = percpu_array_map_seq_show_elem,
|
.map_check_btf = array_map_check_btf,
|
.map_btf_name = "bpf_array",
|
.map_btf_id = &percpu_array_map_btf_id,
|
.iter_seq_info = &iter_seq_info,
|
};
|
|
static int fd_array_map_alloc_check(union bpf_attr *attr)
|
{
|
/* only file descriptors can be stored in this type of map */
|
if (attr->value_size != sizeof(u32))
|
return -EINVAL;
|
/* Program read-only/write-only not supported for special maps yet. */
|
if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG))
|
return -EINVAL;
|
return array_map_alloc_check(attr);
|
}
|
|
static void fd_array_map_free(struct bpf_map *map)
|
{
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
int i;
|
|
/* 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 ERR_PTR(-EOPNOTSUPP);
|
}
|
|
/* only called from syscall */
|
int bpf_fd_array_map_lookup_elem(struct bpf_map *map, void *key, u32 *value)
|
{
|
void **elem, *ptr;
|
int ret = 0;
|
|
if (!map->ops->map_fd_sys_lookup_elem)
|
return -ENOTSUPP;
|
|
rcu_read_lock();
|
elem = array_map_lookup_elem(map, key);
|
if (elem && (ptr = READ_ONCE(*elem)))
|
*value = map->ops->map_fd_sys_lookup_elem(ptr);
|
else
|
ret = -ENOENT;
|
rcu_read_unlock();
|
|
return ret;
|
}
|
|
/* 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);
|
|
if (map->ops->map_poke_run) {
|
mutex_lock(&array->aux->poke_mutex);
|
old_ptr = xchg(array->ptrs + index, new_ptr);
|
map->ops->map_poke_run(map, index, old_ptr, new_ptr);
|
mutex_unlock(&array->aux->poke_mutex);
|
} else {
|
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;
|
|
if (map->ops->map_poke_run) {
|
mutex_lock(&array->aux->poke_mutex);
|
old_ptr = xchg(array->ptrs + index, NULL);
|
map->ops->map_poke_run(map, index, old_ptr, NULL);
|
mutex_unlock(&array->aux->poke_mutex);
|
} else {
|
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);
|
}
|
|
static u32 prog_fd_array_sys_lookup_elem(void *ptr)
|
{
|
return ((struct bpf_prog *)ptr)->aux->id;
|
}
|
|
/* decrement refcnt of all bpf_progs that are stored in this map */
|
static 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 void prog_array_map_seq_show_elem(struct bpf_map *map, void *key,
|
struct seq_file *m)
|
{
|
void **elem, *ptr;
|
u32 prog_id;
|
|
rcu_read_lock();
|
|
elem = array_map_lookup_elem(map, key);
|
if (elem) {
|
ptr = READ_ONCE(*elem);
|
if (ptr) {
|
seq_printf(m, "%u: ", *(u32 *)key);
|
prog_id = prog_fd_array_sys_lookup_elem(ptr);
|
btf_type_seq_show(map->btf, map->btf_value_type_id,
|
&prog_id, m);
|
seq_puts(m, "\n");
|
}
|
}
|
|
rcu_read_unlock();
|
}
|
|
struct prog_poke_elem {
|
struct list_head list;
|
struct bpf_prog_aux *aux;
|
};
|
|
static int prog_array_map_poke_track(struct bpf_map *map,
|
struct bpf_prog_aux *prog_aux)
|
{
|
struct prog_poke_elem *elem;
|
struct bpf_array_aux *aux;
|
int ret = 0;
|
|
aux = container_of(map, struct bpf_array, map)->aux;
|
mutex_lock(&aux->poke_mutex);
|
list_for_each_entry(elem, &aux->poke_progs, list) {
|
if (elem->aux == prog_aux)
|
goto out;
|
}
|
|
elem = kmalloc(sizeof(*elem), GFP_KERNEL);
|
if (!elem) {
|
ret = -ENOMEM;
|
goto out;
|
}
|
|
INIT_LIST_HEAD(&elem->list);
|
/* We must track the program's aux info at this point in time
|
* since the program pointer itself may not be stable yet, see
|
* also comment in prog_array_map_poke_run().
|
*/
|
elem->aux = prog_aux;
|
|
list_add_tail(&elem->list, &aux->poke_progs);
|
out:
|
mutex_unlock(&aux->poke_mutex);
|
return ret;
|
}
|
|
static void prog_array_map_poke_untrack(struct bpf_map *map,
|
struct bpf_prog_aux *prog_aux)
|
{
|
struct prog_poke_elem *elem, *tmp;
|
struct bpf_array_aux *aux;
|
|
aux = container_of(map, struct bpf_array, map)->aux;
|
mutex_lock(&aux->poke_mutex);
|
list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
|
if (elem->aux == prog_aux) {
|
list_del_init(&elem->list);
|
kfree(elem);
|
break;
|
}
|
}
|
mutex_unlock(&aux->poke_mutex);
|
}
|
|
static void prog_array_map_poke_run(struct bpf_map *map, u32 key,
|
struct bpf_prog *old,
|
struct bpf_prog *new)
|
{
|
u8 *old_addr, *new_addr, *old_bypass_addr;
|
struct prog_poke_elem *elem;
|
struct bpf_array_aux *aux;
|
|
aux = container_of(map, struct bpf_array, map)->aux;
|
WARN_ON_ONCE(!mutex_is_locked(&aux->poke_mutex));
|
|
list_for_each_entry(elem, &aux->poke_progs, list) {
|
struct bpf_jit_poke_descriptor *poke;
|
int i, ret;
|
|
for (i = 0; i < elem->aux->size_poke_tab; i++) {
|
poke = &elem->aux->poke_tab[i];
|
|
/* Few things to be aware of:
|
*
|
* 1) We can only ever access aux in this context, but
|
* not aux->prog since it might not be stable yet and
|
* there could be danger of use after free otherwise.
|
* 2) Initially when we start tracking aux, the program
|
* is not JITed yet and also does not have a kallsyms
|
* entry. We skip these as poke->tailcall_target_stable
|
* is not active yet. The JIT will do the final fixup
|
* before setting it stable. The various
|
* poke->tailcall_target_stable are successively
|
* activated, so tail call updates can arrive from here
|
* while JIT is still finishing its final fixup for
|
* non-activated poke entries.
|
* 3) On program teardown, the program's kallsym entry gets
|
* removed out of RCU callback, but we can only untrack
|
* from sleepable context, therefore bpf_arch_text_poke()
|
* might not see that this is in BPF text section and
|
* bails out with -EINVAL. As these are unreachable since
|
* RCU grace period already passed, we simply skip them.
|
* 4) Also programs reaching refcount of zero while patching
|
* is in progress is okay since we're protected under
|
* poke_mutex and untrack the programs before the JIT
|
* buffer is freed. When we're still in the middle of
|
* patching and suddenly kallsyms entry of the program
|
* gets evicted, we just skip the rest which is fine due
|
* to point 3).
|
* 5) Any other error happening below from bpf_arch_text_poke()
|
* is a unexpected bug.
|
*/
|
if (!READ_ONCE(poke->tailcall_target_stable))
|
continue;
|
if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
|
continue;
|
if (poke->tail_call.map != map ||
|
poke->tail_call.key != key)
|
continue;
|
|
old_bypass_addr = old ? NULL : poke->bypass_addr;
|
old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
|
new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
|
|
if (new) {
|
ret = bpf_arch_text_poke(poke->tailcall_target,
|
BPF_MOD_JUMP,
|
old_addr, new_addr);
|
BUG_ON(ret < 0 && ret != -EINVAL);
|
if (!old) {
|
ret = bpf_arch_text_poke(poke->tailcall_bypass,
|
BPF_MOD_JUMP,
|
poke->bypass_addr,
|
NULL);
|
BUG_ON(ret < 0 && ret != -EINVAL);
|
}
|
} else {
|
ret = bpf_arch_text_poke(poke->tailcall_bypass,
|
BPF_MOD_JUMP,
|
old_bypass_addr,
|
poke->bypass_addr);
|
BUG_ON(ret < 0 && ret != -EINVAL);
|
/* let other CPUs finish the execution of program
|
* so that it will not possible to expose them
|
* to invalid nop, stack unwind, nop state
|
*/
|
if (!ret)
|
synchronize_rcu();
|
ret = bpf_arch_text_poke(poke->tailcall_target,
|
BPF_MOD_JUMP,
|
old_addr, NULL);
|
BUG_ON(ret < 0 && ret != -EINVAL);
|
}
|
}
|
}
|
}
|
|
static void prog_array_map_clear_deferred(struct work_struct *work)
|
{
|
struct bpf_map *map = container_of(work, struct bpf_array_aux,
|
work)->map;
|
bpf_fd_array_map_clear(map);
|
bpf_map_put(map);
|
}
|
|
static void prog_array_map_clear(struct bpf_map *map)
|
{
|
struct bpf_array_aux *aux = container_of(map, struct bpf_array,
|
map)->aux;
|
bpf_map_inc(map);
|
schedule_work(&aux->work);
|
}
|
|
static struct bpf_map *prog_array_map_alloc(union bpf_attr *attr)
|
{
|
struct bpf_array_aux *aux;
|
struct bpf_map *map;
|
|
aux = kzalloc(sizeof(*aux), GFP_KERNEL);
|
if (!aux)
|
return ERR_PTR(-ENOMEM);
|
|
INIT_WORK(&aux->work, prog_array_map_clear_deferred);
|
INIT_LIST_HEAD(&aux->poke_progs);
|
mutex_init(&aux->poke_mutex);
|
spin_lock_init(&aux->owner.lock);
|
|
map = array_map_alloc(attr);
|
if (IS_ERR(map)) {
|
kfree(aux);
|
return map;
|
}
|
|
container_of(map, struct bpf_array, map)->aux = aux;
|
aux->map = map;
|
|
return map;
|
}
|
|
static void prog_array_map_free(struct bpf_map *map)
|
{
|
struct prog_poke_elem *elem, *tmp;
|
struct bpf_array_aux *aux;
|
|
aux = container_of(map, struct bpf_array, map)->aux;
|
list_for_each_entry_safe(elem, tmp, &aux->poke_progs, list) {
|
list_del_init(&elem->list);
|
kfree(elem);
|
}
|
kfree(aux);
|
fd_array_map_free(map);
|
}
|
|
/* prog_array->aux->{type,jited} is a runtime binding.
|
* Doing static check alone in the verifier is not enough.
|
* Thus, prog_array_map cannot be used as an inner_map
|
* and map_meta_equal is not implemented.
|
*/
|
static int prog_array_map_btf_id;
|
const struct bpf_map_ops prog_array_map_ops = {
|
.map_alloc_check = fd_array_map_alloc_check,
|
.map_alloc = prog_array_map_alloc,
|
.map_free = prog_array_map_free,
|
.map_poke_track = prog_array_map_poke_track,
|
.map_poke_untrack = prog_array_map_poke_untrack,
|
.map_poke_run = prog_array_map_poke_run,
|
.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,
|
.map_fd_sys_lookup_elem = prog_fd_array_sys_lookup_elem,
|
.map_release_uref = prog_array_map_clear,
|
.map_seq_show_elem = prog_array_map_seq_show_elem,
|
.map_btf_name = "bpf_array",
|
.map_btf_id = &prog_array_map_btf_id,
|
};
|
|
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)
|
{
|
struct bpf_event_entry *ee;
|
struct perf_event *event;
|
struct file *perf_file;
|
u64 value;
|
|
perf_file = perf_event_get(fd);
|
if (IS_ERR(perf_file))
|
return perf_file;
|
|
ee = ERR_PTR(-EOPNOTSUPP);
|
event = perf_file->private_data;
|
if (perf_event_read_local(event, &value, NULL, NULL) == -EOPNOTSUPP)
|
goto err_out;
|
|
ee = bpf_event_entry_gen(perf_file, map_file);
|
if (ee)
|
return ee;
|
ee = ERR_PTR(-ENOMEM);
|
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;
|
|
if (map->map_flags & BPF_F_PRESERVE_ELEMS)
|
return;
|
|
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 void perf_event_fd_array_map_free(struct bpf_map *map)
|
{
|
if (map->map_flags & BPF_F_PRESERVE_ELEMS)
|
bpf_fd_array_map_clear(map);
|
fd_array_map_free(map);
|
}
|
|
static int perf_event_array_map_btf_id;
|
const struct bpf_map_ops perf_event_array_map_ops = {
|
.map_meta_equal = bpf_map_meta_equal,
|
.map_alloc_check = fd_array_map_alloc_check,
|
.map_alloc = array_map_alloc,
|
.map_free = perf_event_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,
|
.map_check_btf = map_check_no_btf,
|
.map_btf_name = "bpf_array",
|
.map_btf_id = &perf_event_array_map_btf_id,
|
};
|
|
#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 int cgroup_array_map_btf_id;
|
const struct bpf_map_ops cgroup_array_map_ops = {
|
.map_meta_equal = bpf_map_meta_equal,
|
.map_alloc_check = fd_array_map_alloc_check,
|
.map_alloc = 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,
|
.map_check_btf = map_check_no_btf,
|
.map_btf_name = "bpf_array",
|
.map_btf_id = &cgroup_array_map_btf_id,
|
};
|
#endif
|
|
static struct bpf_map *array_of_map_alloc(union bpf_attr *attr)
|
{
|
struct bpf_map *map, *inner_map_meta;
|
|
inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd);
|
if (IS_ERR(inner_map_meta))
|
return inner_map_meta;
|
|
map = array_map_alloc(attr);
|
if (IS_ERR(map)) {
|
bpf_map_meta_free(inner_map_meta);
|
return map;
|
}
|
|
map->inner_map_meta = inner_map_meta;
|
|
return map;
|
}
|
|
static void array_of_map_free(struct bpf_map *map)
|
{
|
/* map->inner_map_meta is only accessed by syscall which
|
* is protected by fdget/fdput.
|
*/
|
bpf_map_meta_free(map->inner_map_meta);
|
bpf_fd_array_map_clear(map);
|
fd_array_map_free(map);
|
}
|
|
static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
|
{
|
struct bpf_map **inner_map = array_map_lookup_elem(map, key);
|
|
if (!inner_map)
|
return NULL;
|
|
return READ_ONCE(*inner_map);
|
}
|
|
static int array_of_map_gen_lookup(struct bpf_map *map,
|
struct bpf_insn *insn_buf)
|
{
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
u32 elem_size = round_up(map->value_size, 8);
|
struct bpf_insn *insn = insn_buf;
|
const int ret = BPF_REG_0;
|
const int map_ptr = BPF_REG_1;
|
const int index = BPF_REG_2;
|
|
*insn++ = BPF_ALU64_IMM(BPF_ADD, map_ptr, offsetof(struct bpf_array, value));
|
*insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0);
|
if (!map->bypass_spec_v1) {
|
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 6);
|
*insn++ = BPF_ALU32_IMM(BPF_AND, ret, array->index_mask);
|
} else {
|
*insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5);
|
}
|
if (is_power_of_2(elem_size))
|
*insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(elem_size));
|
else
|
*insn++ = BPF_ALU64_IMM(BPF_MUL, ret, elem_size);
|
*insn++ = BPF_ALU64_REG(BPF_ADD, ret, map_ptr);
|
*insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0);
|
*insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1);
|
*insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1);
|
*insn++ = BPF_MOV64_IMM(ret, 0);
|
|
return insn - insn_buf;
|
}
|
|
static int array_of_maps_map_btf_id;
|
const struct bpf_map_ops array_of_maps_map_ops = {
|
.map_alloc_check = fd_array_map_alloc_check,
|
.map_alloc = array_of_map_alloc,
|
.map_free = array_of_map_free,
|
.map_get_next_key = array_map_get_next_key,
|
.map_lookup_elem = array_of_map_lookup_elem,
|
.map_delete_elem = fd_array_map_delete_elem,
|
.map_fd_get_ptr = bpf_map_fd_get_ptr,
|
.map_fd_put_ptr = bpf_map_fd_put_ptr,
|
.map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem,
|
.map_gen_lookup = array_of_map_gen_lookup,
|
.map_check_btf = map_check_no_btf,
|
.map_btf_name = "bpf_array",
|
.map_btf_id = &array_of_maps_map_btf_id,
|
};
|
