samples/bpf/tracex6_user.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #define _GNU_SOURCE
0003
0004 #include <assert.h>
0005 #include <fcntl.h>
0006 #include <linux/perf_event.h>
0007 #include <sched.h>
0008 #include <stdio.h>
0009 #include <stdlib.h>
0010 #include <sys/ioctl.h>
0011 #include <sys/time.h>
0012 #include <sys/types.h>
0013 #include <sys/wait.h>
0014 #include <unistd.h>
0015
0016 #include <bpf/bpf.h>
0017 #include <bpf/libbpf.h>
0018 #include "perf-sys.h"
0019
0020 #define SAMPLE_PERIOD  0x7fffffffffffffffULL
0021
0022 /* counters, values, values2 */
0023 static int map_fd[3];
0024
0025 static void check_on_cpu(int cpu, struct perf_event_attr *attr)
0026 {
0027     struct bpf_perf_event_value value2;
0028     int pmu_fd, error = 0;
0029     cpu_set_t set;
0030     __u64 value;
0031
0032     /* Move to target CPU */
0033     CPU_ZERO(&set);
0034     CPU_SET(cpu, &set);
0035     assert(sched_setaffinity(0, sizeof(set), &set) == 0);
0036     /* Open perf event and attach to the perf_event_array */
0037     pmu_fd = sys_perf_event_open(attr, -1/*pid*/, cpu/*cpu*/, -1/*group_fd*/, 0);
0038     if (pmu_fd < 0) {
0039         fprintf(stderr, "sys_perf_event_open failed on CPU %d\n", cpu);
0040         error = 1;
0041         goto on_exit;
0042     }
0043     assert(bpf_map_update_elem(map_fd[0], &cpu, &pmu_fd, BPF_ANY) == 0);
0044     assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0);
0045     /* Trigger the kprobe */
0046     bpf_map_get_next_key(map_fd[1], &cpu, NULL);
0047     /* Check the value */
0048     if (bpf_map_lookup_elem(map_fd[1], &cpu, &value)) {
0049         fprintf(stderr, "Value missing for CPU %d\n", cpu);
0050         error = 1;
0051         goto on_exit;
0052     } else {
0053         fprintf(stderr, "CPU %d: %llu\n", cpu, value);
0054     }
0055     /* The above bpf_map_lookup_elem should trigger the second kprobe */
0056     if (bpf_map_lookup_elem(map_fd[2], &cpu, &value2)) {
0057         fprintf(stderr, "Value2 missing for CPU %d\n", cpu);
0058         error = 1;
0059         goto on_exit;
0060     } else {
0061         fprintf(stderr, "CPU %d: counter: %llu, enabled: %llu, running: %llu\n", cpu,
0062             value2.counter, value2.enabled, value2.running);
0063     }
0064
0065 on_exit:
0066     assert(bpf_map_delete_elem(map_fd[0], &cpu) == 0 || error);
0067     assert(ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE, 0) == 0 || error);
0068     assert(close(pmu_fd) == 0 || error);
0069     assert(bpf_map_delete_elem(map_fd[1], &cpu) == 0 || error);
0070     exit(error);
0071 }
0072
0073 static void test_perf_event_array(struct perf_event_attr *attr,
0074                   const char *name)
0075 {
0076     int i, status, nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
0077     pid_t pid[nr_cpus];
0078     int err = 0;
0079
0080     printf("Test reading %s counters\n", name);
0081
0082     for (i = 0; i < nr_cpus; i++) {
0083         pid[i] = fork();
0084         assert(pid[i] >= 0);
0085         if (pid[i] == 0) {
0086             check_on_cpu(i, attr);
0087             exit(1);
0088         }
0089     }
0090
0091     for (i = 0; i < nr_cpus; i++) {
0092         assert(waitpid(pid[i], &status, 0) == pid[i]);
0093         err |= status;
0094     }
0095
0096     if (err)
0097         printf("Test: %s FAILED\n", name);
0098 }
0099
0100 static void test_bpf_perf_event(void)
0101 {
0102     struct perf_event_attr attr_cycles = {
0103         .freq = 0,
0104         .sample_period = SAMPLE_PERIOD,
0105         .inherit = 0,
0106         .type = PERF_TYPE_HARDWARE,
0107         .read_format = 0,
0108         .sample_type = 0,
0109         .config = PERF_COUNT_HW_CPU_CYCLES,
0110     };
0111     struct perf_event_attr attr_clock = {
0112         .freq = 0,
0113         .sample_period = SAMPLE_PERIOD,
0114         .inherit = 0,
0115         .type = PERF_TYPE_SOFTWARE,
0116         .read_format = 0,
0117         .sample_type = 0,
0118         .config = PERF_COUNT_SW_CPU_CLOCK,
0119     };
0120     struct perf_event_attr attr_raw = {
0121         .freq = 0,
0122         .sample_period = SAMPLE_PERIOD,
0123         .inherit = 0,
0124         .type = PERF_TYPE_RAW,
0125         .read_format = 0,
0126         .sample_type = 0,
0127         /* Intel Instruction Retired */
0128         .config = 0xc0,
0129     };
0130     struct perf_event_attr attr_l1d_load = {
0131         .freq = 0,
0132         .sample_period = SAMPLE_PERIOD,
0133         .inherit = 0,
0134         .type = PERF_TYPE_HW_CACHE,
0135         .read_format = 0,
0136         .sample_type = 0,
0137         .config =
0138             PERF_COUNT_HW_CACHE_L1D |
0139             (PERF_COUNT_HW_CACHE_OP_READ << 8) |
0140             (PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
0141     };
0142     struct perf_event_attr attr_llc_miss = {
0143         .freq = 0,
0144         .sample_period = SAMPLE_PERIOD,
0145         .inherit = 0,
0146         .type = PERF_TYPE_HW_CACHE,
0147         .read_format = 0,
0148         .sample_type = 0,
0149         .config =
0150             PERF_COUNT_HW_CACHE_LL |
0151             (PERF_COUNT_HW_CACHE_OP_READ << 8) |
0152             (PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
0153     };
0154     struct perf_event_attr attr_msr_tsc = {
0155         .freq = 0,
0156         .sample_period = 0,
0157         .inherit = 0,
0158         /* From /sys/bus/event_source/devices/msr/ */
0159         .type = 7,
0160         .read_format = 0,
0161         .sample_type = 0,
0162         .config = 0,
0163     };
0164
0165     test_perf_event_array(&attr_cycles, "HARDWARE-cycles");
0166     test_perf_event_array(&attr_clock, "SOFTWARE-clock");
0167     test_perf_event_array(&attr_raw, "RAW-instruction-retired");
0168     test_perf_event_array(&attr_l1d_load, "HW_CACHE-L1D-load");
0169
0170     /* below tests may fail in qemu */
0171     test_perf_event_array(&attr_llc_miss, "HW_CACHE-LLC-miss");
0172     test_perf_event_array(&attr_msr_tsc, "Dynamic-msr-tsc");
0173 }
0174
0175 int main(int argc, char **argv)
0176 {
0177     struct bpf_link *links[2];
0178     struct bpf_program *prog;
0179     struct bpf_object *obj;
0180     char filename[256];
0181     int i = 0;
0182
0183     snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
0184     obj = bpf_object__open_file(filename, NULL);
0185     if (libbpf_get_error(obj)) {
0186         fprintf(stderr, "ERROR: opening BPF object file failed\n");
0187         return 0;
0188     }
0189
0190     /* load BPF program */
0191     if (bpf_object__load(obj)) {
0192         fprintf(stderr, "ERROR: loading BPF object file failed\n");
0193         goto cleanup;
0194     }
0195
0196     map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counters");
0197     map_fd[1] = bpf_object__find_map_fd_by_name(obj, "values");
0198     map_fd[2] = bpf_object__find_map_fd_by_name(obj, "values2");
0199     if (map_fd[0] < 0 || map_fd[1] < 0 || map_fd[2] < 0) {
0200         fprintf(stderr, "ERROR: finding a map in obj file failed\n");
0201         goto cleanup;
0202     }
0203
0204     bpf_object__for_each_program(prog, obj) {
0205         links[i] = bpf_program__attach(prog);
0206         if (libbpf_get_error(links[i])) {
0207             fprintf(stderr, "ERROR: bpf_program__attach failed\n");
0208             links[i] = NULL;
0209             goto cleanup;
0210         }
0211         i++;
0212     }
0213
0214     test_bpf_perf_event();
0215
0216 cleanup:
0217     for (i--; i >= 0; i--)
0218         bpf_link__destroy(links[i]);
0219
0220     bpf_object__close(obj);
0221     return 0;
0222 }