diff options
| -rw-r--r-- | include/linux/bpf.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/bpf.h | 1 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 48 | ||||
| -rw-r--r-- | kernel/trace/bpf_trace.c | 31 |
4 files changed, 66 insertions, 15 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 4fc1f4070789..f57d7fed9ec3 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -190,6 +190,7 @@ extern const struct bpf_func_proto bpf_map_lookup_elem_proto; extern const struct bpf_func_proto bpf_map_update_elem_proto; extern const struct bpf_func_proto bpf_map_delete_elem_proto; +extern const struct bpf_func_proto bpf_perf_event_read_proto; extern const struct bpf_func_proto bpf_get_prandom_u32_proto; extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; extern const struct bpf_func_proto bpf_tail_call_proto; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index a1814e8e53a7..92a48e2d5461 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -271,6 +271,7 @@ enum bpf_func_id { */ BPF_FUNC_skb_get_tunnel_key, BPF_FUNC_skb_set_tunnel_key, + BPF_FUNC_perf_event_read, /* u64 bpf_perf_event_read(&map, index) */ __BPF_FUNC_MAX_ID, }; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index cd307df98cb3..48e1c7192560 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -238,6 +238,14 @@ static const char * const reg_type_str[] = { [CONST_IMM] = "imm", }; +static const struct { + int map_type; + int func_id; +} func_limit[] = { + {BPF_MAP_TYPE_PROG_ARRAY, BPF_FUNC_tail_call}, + {BPF_MAP_TYPE_PERF_EVENT_ARRAY, BPF_FUNC_perf_event_read}, +}; + static void print_verifier_state(struct verifier_env *env) { enum bpf_reg_type t; @@ -837,6 +845,28 @@ static int check_func_arg(struct verifier_env *env, u32 regno, return err; } +static int check_map_func_compatibility(struct bpf_map *map, int func_id) +{ + bool bool_map, bool_func; + int i; + + if (!map) + return 0; + + for (i = 0; i <= ARRAY_SIZE(func_limit); i++) { + bool_map = (map->map_type == func_limit[i].map_type); + bool_func = (func_id == func_limit[i].func_id); + /* only when map & func pair match it can continue. + * don't allow any other map type to be passed into + * the special func; + */ + if (bool_map != bool_func) + return -EINVAL; + } + + return 0; +} + static int check_call(struct verifier_env *env, int func_id) { struct verifier_state *state = &env->cur_state; @@ -912,21 +942,9 @@ static int check_call(struct verifier_env *env, int func_id) return -EINVAL; } - if (map && map->map_type == BPF_MAP_TYPE_PROG_ARRAY && - func_id != BPF_FUNC_tail_call) - /* prog_array map type needs extra care: - * only allow to pass it into bpf_tail_call() for now. - * bpf_map_delete_elem() can be allowed in the future, - * while bpf_map_update_elem() must only be done via syscall - */ - return -EINVAL; - - if (func_id == BPF_FUNC_tail_call && - map->map_type != BPF_MAP_TYPE_PROG_ARRAY) - /* don't allow any other map type to be passed into - * bpf_tail_call() - */ - return -EINVAL; + err = check_map_func_compatibility(map, func_id); + if (err) + return err; return 0; } diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 88a041adee90..ef9936df1b04 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -158,6 +158,35 @@ const struct bpf_func_proto *bpf_get_trace_printk_proto(void) return &bpf_trace_printk_proto; } +static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5) +{ + struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; + struct bpf_array *array = container_of(map, struct bpf_array, map); + struct perf_event *event; + + if (unlikely(index >= array->map.max_entries)) + return -E2BIG; + + event = (struct perf_event *)array->ptrs[index]; + if (!event) + return -ENOENT; + + /* + * we don't know if the function is run successfully by the + * return value. It can be judged in other places, such as + * eBPF programs. + */ + return perf_event_read_local(event); +} + +const struct bpf_func_proto bpf_perf_event_read_proto = { + .func = bpf_perf_event_read, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_ANYTHING, +}; + static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id) { switch (func_id) { @@ -183,6 +212,8 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func return bpf_get_trace_printk_proto(); case BPF_FUNC_get_smp_processor_id: return &bpf_get_smp_processor_id_proto; + case BPF_FUNC_perf_event_read: + return &bpf_perf_event_read_proto; default: return NULL; } |