131 lines · c
1// SPDX-License-Identifier: GPL-2.02/* Copyright (c) 2021 Facebook */3#include <test_progs.h>4#include "get_branch_snapshot.skel.h"5 6static int *pfd_array;7static int cpu_cnt;8 9static bool is_hypervisor(void)10{11 char *line = NULL;12 bool ret = false;13 size_t len;14 FILE *fp;15 16 fp = fopen("/proc/cpuinfo", "r");17 if (!fp)18 return false;19 20 while (getline(&line, &len, fp) != -1) {21 if (!strncmp(line, "flags", 5)) {22 if (strstr(line, "hypervisor") != NULL)23 ret = true;24 break;25 }26 }27 28 free(line);29 fclose(fp);30 return ret;31}32 33static int create_perf_events(void)34{35 struct perf_event_attr attr = {0};36 int cpu;37 38 /* create perf event */39 attr.size = sizeof(attr);40 attr.type = PERF_TYPE_HARDWARE;41 attr.config = PERF_COUNT_HW_CPU_CYCLES;42 attr.sample_type = PERF_SAMPLE_BRANCH_STACK;43 attr.branch_sample_type = PERF_SAMPLE_BRANCH_KERNEL |44 PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY;45 46 cpu_cnt = libbpf_num_possible_cpus();47 pfd_array = malloc(sizeof(int) * cpu_cnt);48 if (!pfd_array) {49 cpu_cnt = 0;50 return 1;51 }52 53 for (cpu = 0; cpu < cpu_cnt; cpu++) {54 pfd_array[cpu] = syscall(__NR_perf_event_open, &attr,55 -1, cpu, -1, PERF_FLAG_FD_CLOEXEC);56 if (pfd_array[cpu] < 0)57 break;58 }59 60 return cpu == 0;61}62 63static void close_perf_events(void)64{65 int cpu, fd;66 67 for (cpu = 0; cpu < cpu_cnt; cpu++) {68 fd = pfd_array[cpu];69 if (fd < 0)70 break;71 close(fd);72 }73 free(pfd_array);74}75 76void serial_test_get_branch_snapshot(void)77{78 struct get_branch_snapshot *skel = NULL;79 int err;80 81 /* Skip the test before we fix LBR snapshot for hypervisor. */82 if (is_hypervisor()) {83 test__skip();84 return;85 }86 87 if (create_perf_events()) {88 test__skip(); /* system doesn't support LBR */89 goto cleanup;90 }91 92 skel = get_branch_snapshot__open_and_load();93 if (!ASSERT_OK_PTR(skel, "get_branch_snapshot__open_and_load"))94 goto cleanup;95 96 err = kallsyms_find("bpf_testmod_loop_test", &skel->bss->address_low);97 if (!ASSERT_OK(err, "kallsyms_find"))98 goto cleanup;99 100 /* Just a guess for the end of this function, as module functions101 * in /proc/kallsyms could come in any order.102 */103 skel->bss->address_high = skel->bss->address_low + 128;104 105 err = get_branch_snapshot__attach(skel);106 if (!ASSERT_OK(err, "get_branch_snapshot__attach"))107 goto cleanup;108 109 trigger_module_test_read(100);110 111 if (skel->bss->total_entries < 16) {112 /* too few entries for the hit/waste test */113 test__skip();114 goto cleanup;115 }116 117 ASSERT_GT(skel->bss->test1_hits, 6, "find_looptest_in_lbr");118 119 /* Given we stop LBR in software, we will waste a few entries.120 * But we should try to waste as few as possible entries. We are at121 * about 7 on x86_64 systems.122 * Add a check for < 10 so that we get heads-up when something123 * changes and wastes too many entries.124 */125 ASSERT_LT(skel->bss->wasted_entries, 10, "check_wasted_entries");126 127cleanup:128 get_branch_snapshot__destroy(skel);129 close_perf_events();130}131