20d1b54a52
Function in modules could appear in /proc/kallsyms in random order. ffffffffa02608a0 t bpf_testmod_loop_test ffffffffa02600c0 t __traceiter_bpf_testmod_test_writable_bare ffffffffa0263b60 d __tracepoint_bpf_testmod_test_write_bare ffffffffa02608c0 T bpf_testmod_test_read ffffffffa0260d08 t __SCT__tp_func_bpf_testmod_test_writable_bare ffffffffa0263300 d __SCK__tp_func_bpf_testmod_test_read ffffffffa0260680 T bpf_testmod_test_write ffffffffa0260860 t bpf_testmod_test_mod_kfunc Therefore, we cannot reliably use kallsyms_find_next() to find the end of a function. Replace it with a simple guess (start + 128). This is good enough for this test. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211022234814.318457-1-songliubraving@fb.com
131 lines
2.8 KiB
C
131 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2021 Facebook */
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#include <test_progs.h>
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#include "get_branch_snapshot.skel.h"
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static int *pfd_array;
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static int cpu_cnt;
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static bool is_hypervisor(void)
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{
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char *line = NULL;
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bool ret = false;
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size_t len;
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FILE *fp;
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fp = fopen("/proc/cpuinfo", "r");
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if (!fp)
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return false;
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while (getline(&line, &len, fp) != -1) {
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if (!strncmp(line, "flags", 5)) {
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if (strstr(line, "hypervisor") != NULL)
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ret = true;
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break;
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}
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}
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free(line);
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fclose(fp);
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return ret;
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}
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static int create_perf_events(void)
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{
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struct perf_event_attr attr = {0};
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int cpu;
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/* create perf event */
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attr.size = sizeof(attr);
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attr.type = PERF_TYPE_RAW;
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attr.config = 0x1b00;
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attr.sample_type = PERF_SAMPLE_BRANCH_STACK;
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attr.branch_sample_type = PERF_SAMPLE_BRANCH_KERNEL |
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PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY;
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cpu_cnt = libbpf_num_possible_cpus();
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pfd_array = malloc(sizeof(int) * cpu_cnt);
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if (!pfd_array) {
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cpu_cnt = 0;
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return 1;
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}
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for (cpu = 0; cpu < cpu_cnt; cpu++) {
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pfd_array[cpu] = syscall(__NR_perf_event_open, &attr,
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-1, cpu, -1, PERF_FLAG_FD_CLOEXEC);
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if (pfd_array[cpu] < 0)
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break;
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}
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return cpu == 0;
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}
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static void close_perf_events(void)
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{
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int cpu, fd;
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for (cpu = 0; cpu < cpu_cnt; cpu++) {
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fd = pfd_array[cpu];
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if (fd < 0)
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break;
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close(fd);
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}
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free(pfd_array);
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}
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void serial_test_get_branch_snapshot(void)
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{
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struct get_branch_snapshot *skel = NULL;
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int err;
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/* Skip the test before we fix LBR snapshot for hypervisor. */
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if (is_hypervisor()) {
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test__skip();
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return;
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}
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if (create_perf_events()) {
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test__skip(); /* system doesn't support LBR */
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goto cleanup;
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}
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skel = get_branch_snapshot__open_and_load();
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if (!ASSERT_OK_PTR(skel, "get_branch_snapshot__open_and_load"))
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goto cleanup;
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err = kallsyms_find("bpf_testmod_loop_test", &skel->bss->address_low);
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if (!ASSERT_OK(err, "kallsyms_find"))
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goto cleanup;
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/* Just a guess for the end of this function, as module functions
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* in /proc/kallsyms could come in any order.
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*/
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skel->bss->address_high = skel->bss->address_low + 128;
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err = get_branch_snapshot__attach(skel);
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if (!ASSERT_OK(err, "get_branch_snapshot__attach"))
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goto cleanup;
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trigger_module_test_read(100);
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if (skel->bss->total_entries < 16) {
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/* too few entries for the hit/waste test */
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test__skip();
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goto cleanup;
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}
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ASSERT_GT(skel->bss->test1_hits, 6, "find_looptest_in_lbr");
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/* Given we stop LBR in software, we will waste a few entries.
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* But we should try to waste as few as possible entries. We are at
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* about 7 on x86_64 systems.
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* Add a check for < 10 so that we get heads-up when something
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* changes and wastes too many entries.
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*/
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ASSERT_LT(skel->bss->wasted_entries, 10, "check_wasted_entries");
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cleanup:
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get_branch_snapshot__destroy(skel);
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close_perf_events();
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}
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