[PATCH v6 08/13] user_events: Add self-test for perf_event integration

Beau Belgrave
2021-12-01T18:26:07Z

Tests perf can be attached to and written out correctly. Ensures attach
updates status bits in user programs.

Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
---
tools/testing/selftests/user_events/Makefile | 2 +-
.../testing/selftests/user_events/perf_test.c | 168 ++++++++++++++++++
2 files changed, 169 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/user_events/perf_test.c

diff --git a/tools/testing/selftests/user_events/Makefile b/tools/testing/selftests/user_events/Makefile
index e824b9c2cae7..c765d8635d9a 100644
--- a/tools/testing/selftests/user_events/Makefile
+++ b/tools/testing/selftests/user_events/Makefile
@@ -2,7 +2,7 @@
CFLAGS += -Wl,-no-as-needed -Wall -I../../../../usr/include
LDLIBS += -lrt -lpthread -lm

-TEST_GEN_PROGS = ftrace_test dyn_test
+TEST_GEN_PROGS = ftrace_test dyn_test perf_test

TEST_FILES := settings

diff --git a/tools/testing/selftests/user_events/perf_test.c b/tools/testing/selftests/user_events/perf_test.c
new file mode 100644
index 000000000000..26851d51d6bb
--- /dev/null
+++ b/tools/testing/selftests/user_events/perf_test.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * User Events Perf Events Test Program
+ *
+ * Copyright (c) 2021 Beau Belgrave <beaub@linux.microsoft.com>
+ */
+
+#include <errno.h>
+#include <linux/user_events.h>
+#include <linux/perf_event.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <asm/unistd.h>
+
+#include "../kselftest_harness.h"
+
+const char *data_file = "/sys/kernel/debug/tracing/user_events_data";
+const char *status_file = "/sys/kernel/debug/tracing/user_events_status";
+const char *id_file = "/sys/kernel/debug/tracing/events/user_events/__test_event/id";
+const char *fmt_file = "/sys/kernel/debug/tracing/events/user_events/__test_event/format";
+
+struct event {
+ __u32 index;
+ __u32 field1;
+ __u32 field2;
+};
+
+static long perf_event_open(struct perf_event_attr *pe, pid_t pid,
+ int cpu, int group_fd, unsigned long flags)
+{
+ return syscall(__NR_perf_event_open, pe, pid, cpu, group_fd, flags);
+}
+
+static int get_id(void)
+{
+ FILE *fp = fopen(id_file, "r");
+ int ret, id = 0;
+
+ if (!fp)
+ return -1;
+
+ ret = fscanf(fp, "%d", &id);
+ fclose(fp);
+
+ if (ret != 1)
+ return -1;
+
+ return id;
+}
+
+static int get_offset(void)
+{
+ FILE *fp = fopen(fmt_file, "r");
+ int ret, c, last = 0, offset = 0;
+
+ if (!fp)
+ return -1;
+
+ /* Read until empty line */
+ while (true) {
+ c = getc(fp);
+
+ if (c == EOF)
+ break;
+
+ if (last == '\n' && c == '\n')
+ break;
+
+ last = c;
+ }
+
+ ret = fscanf(fp, "\tfield:u32 field1;\toffset:%d;", &offset);
+ fclose(fp);
+
+ if (ret != 1)
+ return -1;
+
+ return offset;
+}
+
+FIXTURE(user) {
+ int status_fd;
+ int data_fd;
+};
+
+FIXTURE_SETUP(user) {
+ self->status_fd = open(status_file, O_RDONLY);
+ ASSERT_NE(-1, self->status_fd);
+
+ self->data_fd = open(data_file, O_RDWR);
+ ASSERT_NE(-1, self->data_fd);
+}
+
+FIXTURE_TEARDOWN(user) {
+ close(self->status_fd);
+ close(self->data_fd);
+}
+
+TEST_F(user, perf_write) {
+ struct perf_event_attr pe = {0};
+ struct user_reg reg = {0};
+ int page_size = sysconf(_SC_PAGESIZE);
+ char *status_page;
+ struct event event;
+ struct perf_event_mmap_page *perf_page;
+ int id, fd, offset;
+ __u32 *val;
+
+ reg.size = sizeof(reg);
+ reg.name_args = (__u64)"__test_event u32 field1; u32 field2";
+
+ status_page = mmap(NULL, page_size, PROT_READ, MAP_SHARED,
+ self->status_fd, 0);
+ ASSERT_NE(MAP_FAILED, status_page);
+
+ /* Register should work */
+ ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
+ ASSERT_EQ(0, reg.write_index);
+ ASSERT_NE(0, reg.status_index);
+ ASSERT_EQ(0, status_page[reg.status_index]);
+
+ /* Id should be there */
+ id = get_id();
+ ASSERT_NE(-1, id);
+ offset = get_offset();
+ ASSERT_NE(-1, offset);
+
+ pe.type = PERF_TYPE_TRACEPOINT;
+ pe.size = sizeof(pe);
+ pe.config = id;
+ pe.sample_type = PERF_SAMPLE_RAW;
+ pe.sample_period = 1;
+ pe.wakeup_events = 1;
+
+ /* Tracepoint attach should work */
+ fd = perf_event_open(&pe, 0, -1, -1, 0);
+ ASSERT_NE(-1, fd);
+
+ perf_page = mmap(NULL, page_size * 2, PROT_READ, MAP_SHARED, fd, 0);
+ ASSERT_NE(MAP_FAILED, perf_page);
+
+ /* Status should be updated */
+ ASSERT_EQ(EVENT_STATUS_PERF, status_page[reg.status_index]);
+
+ event.index = reg.write_index;
+ event.field1 = 0xc001;
+ event.field2 = 0xc01a;
+
+ /* Ensure write shows up at correct offset */
+ ASSERT_NE(-1, write(self->data_fd, &event, sizeof(event)));
+ val = (void *)(((char *)perf_page) + perf_page->data_offset);
+ ASSERT_EQ(PERF_RECORD_SAMPLE, *val);
+ /* Skip over header and size, move to offset */
+ val += 3;
+ val = (void *)((char *)val) + offset;
+ /* Ensure correct */
+ ASSERT_EQ(event.field1, *val++);
+ ASSERT_EQ(event.field2, *val++);
+}
+
+int main(int argc, char **argv)
+{
+ return test_harness_run(argc, argv);
+}
--
2.17.1