From 35578d7984003097af2b1e34502bc943d40c1804 Mon Sep 17 00:00:00 2001 From: Kaixu Xia Date: Thu, 6 Aug 2015 07:02:35 +0000 Subject: bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter According to the perf_event_map_fd and index, the function bpf_perf_event_read() can convert the corresponding map value to the pointer to struct perf_event and return the Hardware PMU counter value. Signed-off-by: Kaixu Xia Signed-off-by: David S. Miller --- kernel/bpf/verifier.c | 48 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 33 insertions(+), 15 deletions(-) (limited to 'kernel/bpf') diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index cd307df..48e1c71 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; } -- cgit v1.1