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 <xiakaixu@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 @@
[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 @@
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 @@
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;
}
