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linux-next/samples/bpf/tracex6_kern.c
Yonghong Song 020a32d958 bpf: add a test case for helper bpf_perf_event_read_value
The bpf sample program tracex6 is enhanced to use the new
helper to read enabled/running time as well.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-07 23:05:57 +01:00

68 lines
1.5 KiB
C

#include <linux/ptrace.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"
struct bpf_map_def SEC("maps") counters = {
.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(u32),
.max_entries = 64,
};
struct bpf_map_def SEC("maps") values = {
.type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(int),
.value_size = sizeof(u64),
.max_entries = 64,
};
struct bpf_map_def SEC("maps") values2 = {
.type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(int),
.value_size = sizeof(struct bpf_perf_event_value),
.max_entries = 64,
};
SEC("kprobe/htab_map_get_next_key")
int bpf_prog1(struct pt_regs *ctx)
{
u32 key = bpf_get_smp_processor_id();
u64 count, *val;
s64 error;
count = bpf_perf_event_read(&counters, key);
error = (s64)count;
if (error <= -2 && error >= -22)
return 0;
val = bpf_map_lookup_elem(&values, &key);
if (val)
*val = count;
else
bpf_map_update_elem(&values, &key, &count, BPF_NOEXIST);
return 0;
}
SEC("kprobe/htab_map_lookup_elem")
int bpf_prog2(struct pt_regs *ctx)
{
u32 key = bpf_get_smp_processor_id();
struct bpf_perf_event_value *val, buf;
int error;
error = bpf_perf_event_read_value(&counters, key, &buf, sizeof(buf));
if (error)
return 0;
val = bpf_map_lookup_elem(&values2, &key);
if (val)
*val = buf;
else
bpf_map_update_elem(&values2, &key, &buf, BPF_NOEXIST);
return 0;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;