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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */
#include <test_progs.h>
#include "get_branch_snapshot.skel.h"
static int *pfd_array;
static int cpu_cnt;
static bool is_hypervisor(void)
{
char *line = NULL;
bool ret = false;
size_t len;
FILE *fp;
fp = fopen("/proc/cpuinfo", "r");
if (!fp)
return false;
while (getline(&line, &len, fp) != -1) {
if (!strncmp(line, "flags", 5)) {
if (strstr(line, "hypervisor") != NULL)
ret = true;
break;
}
}
free(line);
fclose(fp);
return ret;
}
static int create_perf_events(void)
{
struct perf_event_attr attr = {0};
int cpu;
/* create perf event */
attr.size = sizeof(attr);
attr.type = PERF_TYPE_RAW;
attr.config = 0x1b00;
attr.sample_type = PERF_SAMPLE_BRANCH_STACK;
attr.branch_sample_type = PERF_SAMPLE_BRANCH_KERNEL |
PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY;
cpu_cnt = libbpf_num_possible_cpus();
pfd_array = malloc(sizeof(int) * cpu_cnt);
if (!pfd_array) {
cpu_cnt = 0;
return 1;
}
for (cpu = 0; cpu < cpu_cnt; cpu++) {
pfd_array[cpu] = syscall(__NR_perf_event_open, &attr,
-1, cpu, -1, PERF_FLAG_FD_CLOEXEC);
if (pfd_array[cpu] < 0)
break;
}
return cpu == 0;
}
static void close_perf_events(void)
{
int cpu, fd;
for (cpu = 0; cpu < cpu_cnt; cpu++) {
fd = pfd_array[cpu];
if (fd < 0)
break;
close(fd);
}
free(pfd_array);
}
void test_get_branch_snapshot(void)
{
struct get_branch_snapshot *skel = NULL;
int err;
if (create_perf_events()) {
test__skip(); /* system doesn't support LBR */
goto cleanup;
}
skel = get_branch_snapshot__open_and_load();
if (!ASSERT_OK_PTR(skel, "get_branch_snapshot__open_and_load"))
goto cleanup;
err = kallsyms_find("bpf_testmod_loop_test", &skel->bss->address_low);
if (!ASSERT_OK(err, "kallsyms_find"))
goto cleanup;
err = kallsyms_find_next("bpf_testmod_loop_test", &skel->bss->address_high);
if (!ASSERT_OK(err, "kallsyms_find_next"))
goto cleanup;
err = get_branch_snapshot__attach(skel);
if (!ASSERT_OK(err, "get_branch_snapshot__attach"))
goto cleanup;
trigger_module_test_read(100);
if (skel->bss->total_entries < 16) {
/* too few entries for the hit/waste test */
test__skip();
goto cleanup;
}
if (is_hypervisor()) {
/* As of today, LBR in hypervisor cannot be stopped before
* too many entries are flushed. Skip the hit/waste test
* for now in hypervisor until we optimize the LBR in
* hypervisor.
*/
test__skip();
goto cleanup;
}
ASSERT_GT(skel->bss->test1_hits, 6, "find_looptest_in_lbr");
/* Given we stop LBR in software, we will waste a few entries.
* But we should try to waste as few as possible entries. We are at
* about 7 on x86_64 systems.
* Add a check for < 10 so that we get heads-up when something
* changes and wastes too many entries.
*/
ASSERT_LT(skel->bss->wasted_entries, 10, "check_wasted_entries");
cleanup:
get_branch_snapshot__destroy(skel);
close_perf_events();
}
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