diff options
Diffstat (limited to 'kernel/bpf/arraymap.c')
| -rw-r--r-- | kernel/bpf/arraymap.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 6b6f41f0b211..bc9da93db403 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -1,4 +1,5 @@ /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com + * Copyright (c) 2016,2017 Facebook * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public @@ -16,6 +17,8 @@ #include <linux/filter.h> #include <linux/perf_event.h> +#include "map_in_map.h" + static void bpf_array_free_percpu(struct bpf_array *array) { int i; @@ -113,6 +116,30 @@ static void *array_map_lookup_elem(struct bpf_map *map, void *key) return array->value + array->elem_size * index; } +/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */ +static u32 array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf) +{ + struct bpf_insn *insn = insn_buf; + u32 elem_size = round_up(map->value_size, 8); + 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); + *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 3); + + 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_JMP_IMM(BPF_JA, 0, 0, 1); + *insn++ = BPF_MOV64_IMM(ret, 0); + return insn - insn_buf; +} + /* Called from eBPF program */ static void *percpu_array_map_lookup_elem(struct bpf_map *map, void *key) { @@ -267,6 +294,7 @@ static const struct bpf_map_ops array_ops = { .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, }; static struct bpf_map_type_list array_type __ro_after_init = { @@ -576,3 +604,64 @@ static int __init register_cgroup_array_map(void) } late_initcall(register_cgroup_array_map); #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 = fd_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 const struct bpf_map_ops array_of_map_ops = { + .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, +}; + +static struct bpf_map_type_list array_of_map_type __ro_after_init = { + .ops = &array_of_map_ops, + .type = BPF_MAP_TYPE_ARRAY_OF_MAPS, +}; + +static int __init register_array_of_map(void) +{ + bpf_register_map_type(&array_of_map_type); + return 0; +} +late_initcall(register_array_of_map); |