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bpf/tracing: add a bpf test for new ioctl query interface

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Added a subtest in test_progs. The tracepoint is
sched/sched_switch. Multiple bpf programs are attached to
this tracepoint and the query interface is exercised.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song 2017-12-11 11:39:03 -08:00 committed by Alexei Starovoitov
parent f371b304f1
commit d279f1f8c6
4 changed files with 182 additions and 1 deletions
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22
tools/include/uapi/linux/perf_event.h
View File

@ -418,6 +418,27 @@ struct perf_event_attr {
__u16 __reserved_2; /* align to __u64 */
};
/*
* Structure used by below PERF_EVENT_IOC_QUERY_BPF command
* to query bpf programs attached to the same perf tracepoint
* as the given perf event.
*/
struct perf_event_query_bpf {
/*
* The below ids array length
*/
__u32 ids_len;
/*
* Set by the kernel to indicate the number of
* available programs
*/
__u32 prog_cnt;
/*
* User provided buffer to store program ids
*/
__u32 ids[0];
};
#define perf_flags(attr) (*(&(attr)->read_format + 1))
/*
@ -433,6 +454,7 @@ struct perf_event_attr {
#define PERF_EVENT_IOC_ID _IOR('$', 7, __u64 *)
#define PERF_EVENT_IOC_SET_BPF _IOW('$', 8, __u32)
#define PERF_EVENT_IOC_PAUSE_OUTPUT _IOW('$', 9, __u32)
#define PERF_EVENT_IOC_QUERY_BPF _IOWR('$', 10, struct perf_event_query_bpf *)
enum perf_event_ioc_flags {
PERF_IOC_FLAG_GROUP = 1U << 0,

2
tools/testing/selftests/bpf/Makefile
View File

@ -17,7 +17,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \
sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o
sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o test_tracepoint.o
TEST_PROGS := test_kmod.sh test_xdp_redirect.sh test_xdp_meta.sh \
test_offload.py

133
tools/testing/selftests/bpf/test_progs.c
View File

@ -21,8 +21,10 @@ typedef __u16 __sum16;
#include <linux/ipv6.h>
#include <linux/tcp.h>
#include <linux/filter.h>
#include <linux/perf_event.h>
#include <linux/unistd.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <sys/resource.h>
#include <sys/types.h>
@ -617,6 +619,136 @@ static void test_obj_name(void)
}
}
static void test_tp_attach_query(void)
{
const int num_progs = 3;
int i, j, bytes, efd, err, prog_fd[num_progs], pmu_fd[num_progs];
__u32 duration = 0, info_len, saved_prog_ids[num_progs];
const char *file = "./test_tracepoint.o";
struct perf_event_query_bpf *query;
struct perf_event_attr attr = {};
struct bpf_object *obj[num_progs];
struct bpf_prog_info prog_info;
char buf[256];
snprintf(buf, sizeof(buf),
"/sys/kernel/debug/tracing/events/sched/sched_switch/id");
efd = open(buf, O_RDONLY, 0);
if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno))
return;
bytes = read(efd, buf, sizeof(buf));
close(efd);
if (CHECK(bytes <= 0 || bytes >= sizeof(buf),
"read", "bytes %d errno %d\n", bytes, errno))
return;
attr.config = strtol(buf, NULL, 0);
attr.type = PERF_TYPE_TRACEPOINT;
attr.sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN;
attr.sample_period = 1;
attr.wakeup_events = 1;
query = malloc(sizeof(*query) + sizeof(__u32) * num_progs);
for (i = 0; i < num_progs; i++) {
err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj[i],
&prog_fd[i]);
if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno))
goto cleanup1;
bzero(&prog_info, sizeof(prog_info));
prog_info.jited_prog_len = 0;
prog_info.xlated_prog_len = 0;
prog_info.nr_map_ids = 0;
info_len = sizeof(prog_info);
err = bpf_obj_get_info_by_fd(prog_fd[i], &prog_info, &info_len);
if (CHECK(err, "bpf_obj_get_info_by_fd", "err %d errno %d\n",
err, errno))
goto cleanup1;
saved_prog_ids[i] = prog_info.id;
pmu_fd[i] = syscall(__NR_perf_event_open, &attr, -1 /* pid */,
0 /* cpu 0 */, -1 /* group id */,
0 /* flags */);
if (CHECK(pmu_fd[i] < 0, "perf_event_open", "err %d errno %d\n",
pmu_fd[i], errno))
goto cleanup2;
err = ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0);
if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n",
err, errno))
goto cleanup3;
if (i == 0) {
/* check NULL prog array query */
query->ids_len = num_progs;
err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, query);
if (CHECK(err || query->prog_cnt != 0,
"perf_event_ioc_query_bpf",
"err %d errno %d query->prog_cnt %u\n",
err, errno, query->prog_cnt))
goto cleanup3;
}
err = ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[i]);
if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n",
err, errno))
goto cleanup3;
if (i == 1) {
/* try to get # of programs only */
query->ids_len = 0;
err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, query);
if (CHECK(err || query->prog_cnt != 2,
"perf_event_ioc_query_bpf",
"err %d errno %d query->prog_cnt %u\n",
err, errno, query->prog_cnt))
goto cleanup3;
/* try a few negative tests */
/* invalid query pointer */
err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF,
(struct perf_event_query_bpf *)0x1);
if (CHECK(!err || errno != EFAULT,
"perf_event_ioc_query_bpf",
"err %d errno %d\n", err, errno))
goto cleanup3;
/* no enough space */
query->ids_len = 1;
err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, query);
if (CHECK(!err || errno != ENOSPC || query->prog_cnt != 2,
"perf_event_ioc_query_bpf",
"err %d errno %d query->prog_cnt %u\n",
err, errno, query->prog_cnt))
goto cleanup3;
}
query->ids_len = num_progs;
err = ioctl(pmu_fd[i], PERF_EVENT_IOC_QUERY_BPF, query);
if (CHECK(err || query->prog_cnt != (i + 1),
"perf_event_ioc_query_bpf",
"err %d errno %d query->prog_cnt %u\n",
err, errno, query->prog_cnt))
goto cleanup3;
for (j = 0; j < i + 1; j++)
if (CHECK(saved_prog_ids[j] != query->ids[j],
"perf_event_ioc_query_bpf",
"#%d saved_prog_id %x query prog_id %x\n",
j, saved_prog_ids[j], query->ids[j]))
goto cleanup3;
}
i = num_progs - 1;
for (; i >= 0; i--) {
cleanup3:
ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
cleanup2:
close(pmu_fd[i]);
cleanup1:
bpf_object__close(obj[i]);
}
free(query);
}
int main(void)
{
struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
@ -630,6 +762,7 @@ int main(void)
test_bpf_obj_id();
test_pkt_md_access();
test_obj_name();
test_tp_attach_query();
printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;

26
tools/testing/selftests/bpf/test_tracepoint.c Normal file
View File

@ -0,0 +1,26 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2017 Facebook
#include <linux/bpf.h>
#include "bpf_helpers.h"
/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
struct sched_switch_args {
unsigned long long pad;
char prev_comm[16];
int prev_pid;
int prev_prio;
long long prev_state;
char next_comm[16];
int next_pid;
int next_prio;
};
SEC("tracepoint/sched/sched_switch")
int oncpu(struct sched_switch_args *ctx)
{
return 0;
}
char _license[] SEC("license") = "GPL";
__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */