mirror of https://gitee.com/openkylin/linux.git
77 lines
1.9 KiB
C
77 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
// Copyright (c) 2018 Facebook
|
|
|
|
#include <linux/bpf.h>
|
|
#include "bpf_helpers.h"
|
|
|
|
#ifndef PERF_MAX_STACK_DEPTH
|
|
#define PERF_MAX_STACK_DEPTH 127
|
|
#endif
|
|
|
|
struct bpf_map_def SEC("maps") control_map = {
|
|
.type = BPF_MAP_TYPE_ARRAY,
|
|
.key_size = sizeof(__u32),
|
|
.value_size = sizeof(__u32),
|
|
.max_entries = 1,
|
|
};
|
|
|
|
struct bpf_map_def SEC("maps") stackid_hmap = {
|
|
.type = BPF_MAP_TYPE_HASH,
|
|
.key_size = sizeof(__u32),
|
|
.value_size = sizeof(__u32),
|
|
.max_entries = 16384,
|
|
};
|
|
|
|
struct bpf_map_def SEC("maps") stackmap = {
|
|
.type = BPF_MAP_TYPE_STACK_TRACE,
|
|
.key_size = sizeof(__u32),
|
|
.value_size = sizeof(struct bpf_stack_build_id)
|
|
* PERF_MAX_STACK_DEPTH,
|
|
.max_entries = 128,
|
|
.map_flags = BPF_F_STACK_BUILD_ID,
|
|
};
|
|
|
|
struct bpf_map_def SEC("maps") stack_amap = {
|
|
.type = BPF_MAP_TYPE_ARRAY,
|
|
.key_size = sizeof(__u32),
|
|
.value_size = sizeof(struct bpf_stack_build_id)
|
|
* PERF_MAX_STACK_DEPTH,
|
|
.max_entries = 128,
|
|
};
|
|
|
|
/* taken from /sys/kernel/debug/tracing/events/random/urandom_read/format */
|
|
struct random_urandom_args {
|
|
unsigned long long pad;
|
|
int got_bits;
|
|
int pool_left;
|
|
int input_left;
|
|
};
|
|
|
|
SEC("tracepoint/random/urandom_read")
|
|
int oncpu(struct random_urandom_args *args)
|
|
{
|
|
__u32 max_len = sizeof(struct bpf_stack_build_id)
|
|
* PERF_MAX_STACK_DEPTH;
|
|
__u32 key = 0, val = 0, *value_p;
|
|
void *stack_p;
|
|
|
|
value_p = bpf_map_lookup_elem(&control_map, &key);
|
|
if (value_p && *value_p)
|
|
return 0; /* skip if non-zero *value_p */
|
|
|
|
/* The size of stackmap and stackid_hmap should be the same */
|
|
key = bpf_get_stackid(args, &stackmap, BPF_F_USER_STACK);
|
|
if ((int)key >= 0) {
|
|
bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
|
|
stack_p = bpf_map_lookup_elem(&stack_amap, &key);
|
|
if (stack_p)
|
|
bpf_get_stack(args, stack_p, max_len,
|
|
BPF_F_USER_STACK | BPF_F_USER_BUILD_ID);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
char _license[] SEC("license") = "GPL";
|
|
__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */
|