63841bc083
Currently, the kprobe BPF program attachment method for bpf_load is quite old. The implementation of bpf_load "directly" controls and manages(create, delete) the kprobe events of DEBUGFS. On the other hand, using using the libbpf automatically manages the kprobe event. (under bpf_link interface) By calling bpf_program__attach(_kprobe) in libbpf, the corresponding kprobe is created and the BPF program will be attached to this kprobe. To remove this, by simply invoking bpf_link__destroy will clean up the event. This commit refactors kprobe tracing programs (tracex{1~7}_user.c) with libbpf using bpf_link interface and bpf_program__attach. tracex2_kern.c, which tracks system calls (sys_*), has been modified to append prefix depending on architecture. Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200516040608.1377876-3-danieltimlee@gmail.com
227 lines
5.6 KiB
C
227 lines
5.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#define _GNU_SOURCE
|
|
|
|
#include <assert.h>
|
|
#include <fcntl.h>
|
|
#include <linux/perf_event.h>
|
|
#include <sched.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/resource.h>
|
|
#include <sys/time.h>
|
|
#include <sys/types.h>
|
|
#include <sys/wait.h>
|
|
#include <unistd.h>
|
|
|
|
#include <bpf/bpf.h>
|
|
#include <bpf/libbpf.h>
|
|
#include "perf-sys.h"
|
|
|
|
#define SAMPLE_PERIOD 0x7fffffffffffffffULL
|
|
|
|
/* counters, values, values2 */
|
|
static int map_fd[3];
|
|
|
|
static void check_on_cpu(int cpu, struct perf_event_attr *attr)
|
|
{
|
|
struct bpf_perf_event_value value2;
|
|
int pmu_fd, error = 0;
|
|
cpu_set_t set;
|
|
__u64 value;
|
|
|
|
/* Move to target CPU */
|
|
CPU_ZERO(&set);
|
|
CPU_SET(cpu, &set);
|
|
assert(sched_setaffinity(0, sizeof(set), &set) == 0);
|
|
/* Open perf event and attach to the perf_event_array */
|
|
pmu_fd = sys_perf_event_open(attr, -1/*pid*/, cpu/*cpu*/, -1/*group_fd*/, 0);
|
|
if (pmu_fd < 0) {
|
|
fprintf(stderr, "sys_perf_event_open failed on CPU %d\n", cpu);
|
|
error = 1;
|
|
goto on_exit;
|
|
}
|
|
assert(bpf_map_update_elem(map_fd[0], &cpu, &pmu_fd, BPF_ANY) == 0);
|
|
assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0);
|
|
/* Trigger the kprobe */
|
|
bpf_map_get_next_key(map_fd[1], &cpu, NULL);
|
|
/* Check the value */
|
|
if (bpf_map_lookup_elem(map_fd[1], &cpu, &value)) {
|
|
fprintf(stderr, "Value missing for CPU %d\n", cpu);
|
|
error = 1;
|
|
goto on_exit;
|
|
} else {
|
|
fprintf(stderr, "CPU %d: %llu\n", cpu, value);
|
|
}
|
|
/* The above bpf_map_lookup_elem should trigger the second kprobe */
|
|
if (bpf_map_lookup_elem(map_fd[2], &cpu, &value2)) {
|
|
fprintf(stderr, "Value2 missing for CPU %d\n", cpu);
|
|
error = 1;
|
|
goto on_exit;
|
|
} else {
|
|
fprintf(stderr, "CPU %d: counter: %llu, enabled: %llu, running: %llu\n", cpu,
|
|
value2.counter, value2.enabled, value2.running);
|
|
}
|
|
|
|
on_exit:
|
|
assert(bpf_map_delete_elem(map_fd[0], &cpu) == 0 || error);
|
|
assert(ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE, 0) == 0 || error);
|
|
assert(close(pmu_fd) == 0 || error);
|
|
assert(bpf_map_delete_elem(map_fd[1], &cpu) == 0 || error);
|
|
exit(error);
|
|
}
|
|
|
|
static void test_perf_event_array(struct perf_event_attr *attr,
|
|
const char *name)
|
|
{
|
|
int i, status, nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
|
|
pid_t pid[nr_cpus];
|
|
int err = 0;
|
|
|
|
printf("Test reading %s counters\n", name);
|
|
|
|
for (i = 0; i < nr_cpus; i++) {
|
|
pid[i] = fork();
|
|
assert(pid[i] >= 0);
|
|
if (pid[i] == 0) {
|
|
check_on_cpu(i, attr);
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < nr_cpus; i++) {
|
|
assert(waitpid(pid[i], &status, 0) == pid[i]);
|
|
err |= status;
|
|
}
|
|
|
|
if (err)
|
|
printf("Test: %s FAILED\n", name);
|
|
}
|
|
|
|
static void test_bpf_perf_event(void)
|
|
{
|
|
struct perf_event_attr attr_cycles = {
|
|
.freq = 0,
|
|
.sample_period = SAMPLE_PERIOD,
|
|
.inherit = 0,
|
|
.type = PERF_TYPE_HARDWARE,
|
|
.read_format = 0,
|
|
.sample_type = 0,
|
|
.config = PERF_COUNT_HW_CPU_CYCLES,
|
|
};
|
|
struct perf_event_attr attr_clock = {
|
|
.freq = 0,
|
|
.sample_period = SAMPLE_PERIOD,
|
|
.inherit = 0,
|
|
.type = PERF_TYPE_SOFTWARE,
|
|
.read_format = 0,
|
|
.sample_type = 0,
|
|
.config = PERF_COUNT_SW_CPU_CLOCK,
|
|
};
|
|
struct perf_event_attr attr_raw = {
|
|
.freq = 0,
|
|
.sample_period = SAMPLE_PERIOD,
|
|
.inherit = 0,
|
|
.type = PERF_TYPE_RAW,
|
|
.read_format = 0,
|
|
.sample_type = 0,
|
|
/* Intel Instruction Retired */
|
|
.config = 0xc0,
|
|
};
|
|
struct perf_event_attr attr_l1d_load = {
|
|
.freq = 0,
|
|
.sample_period = SAMPLE_PERIOD,
|
|
.inherit = 0,
|
|
.type = PERF_TYPE_HW_CACHE,
|
|
.read_format = 0,
|
|
.sample_type = 0,
|
|
.config =
|
|
PERF_COUNT_HW_CACHE_L1D |
|
|
(PERF_COUNT_HW_CACHE_OP_READ << 8) |
|
|
(PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
|
|
};
|
|
struct perf_event_attr attr_llc_miss = {
|
|
.freq = 0,
|
|
.sample_period = SAMPLE_PERIOD,
|
|
.inherit = 0,
|
|
.type = PERF_TYPE_HW_CACHE,
|
|
.read_format = 0,
|
|
.sample_type = 0,
|
|
.config =
|
|
PERF_COUNT_HW_CACHE_LL |
|
|
(PERF_COUNT_HW_CACHE_OP_READ << 8) |
|
|
(PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
|
|
};
|
|
struct perf_event_attr attr_msr_tsc = {
|
|
.freq = 0,
|
|
.sample_period = 0,
|
|
.inherit = 0,
|
|
/* From /sys/bus/event_source/devices/msr/ */
|
|
.type = 7,
|
|
.read_format = 0,
|
|
.sample_type = 0,
|
|
.config = 0,
|
|
};
|
|
|
|
test_perf_event_array(&attr_cycles, "HARDWARE-cycles");
|
|
test_perf_event_array(&attr_clock, "SOFTWARE-clock");
|
|
test_perf_event_array(&attr_raw, "RAW-instruction-retired");
|
|
test_perf_event_array(&attr_l1d_load, "HW_CACHE-L1D-load");
|
|
|
|
/* below tests may fail in qemu */
|
|
test_perf_event_array(&attr_llc_miss, "HW_CACHE-LLC-miss");
|
|
test_perf_event_array(&attr_msr_tsc, "Dynamic-msr-tsc");
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
|
|
struct bpf_link *links[2];
|
|
struct bpf_program *prog;
|
|
struct bpf_object *obj;
|
|
char filename[256];
|
|
int i = 0;
|
|
|
|
setrlimit(RLIMIT_MEMLOCK, &r);
|
|
|
|
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
|
|
obj = bpf_object__open_file(filename, NULL);
|
|
if (libbpf_get_error(obj)) {
|
|
fprintf(stderr, "ERROR: opening BPF object file failed\n");
|
|
return 0;
|
|
}
|
|
|
|
/* load BPF program */
|
|
if (bpf_object__load(obj)) {
|
|
fprintf(stderr, "ERROR: loading BPF object file failed\n");
|
|
goto cleanup;
|
|
}
|
|
|
|
map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counters");
|
|
map_fd[1] = bpf_object__find_map_fd_by_name(obj, "values");
|
|
map_fd[2] = bpf_object__find_map_fd_by_name(obj, "values2");
|
|
if (map_fd[0] < 0 || map_fd[1] < 0 || map_fd[2] < 0) {
|
|
fprintf(stderr, "ERROR: finding a map in obj file failed\n");
|
|
goto cleanup;
|
|
}
|
|
|
|
bpf_object__for_each_program(prog, obj) {
|
|
links[i] = bpf_program__attach(prog);
|
|
if (libbpf_get_error(links[i])) {
|
|
fprintf(stderr, "ERROR: bpf_program__attach failed\n");
|
|
links[i] = NULL;
|
|
goto cleanup;
|
|
}
|
|
i++;
|
|
}
|
|
|
|
test_bpf_perf_event();
|
|
|
|
cleanup:
|
|
for (i--; i >= 0; i--)
|
|
bpf_link__destroy(links[i]);
|
|
|
|
bpf_object__close(obj);
|
|
return 0;
|
|
}
|