Commit 35578d79 authored by Kaixu Xia's avatar Kaixu Xia Committed by David S. Miller
Browse files

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: default avatarKaixu Xia <xiakaixu@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ea317b26
......@@ -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;
......
......@@ -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,
};
......
......@@ -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;
}
......
......@@ -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;
}
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment