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Subject[PATCH 6/6] perf tests: Add breakpoint accounting/modify test
Date
Adding test that:
- detects the number of watch/break-points,
skip test if any is missing
- detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
skip test if it's missing
- detects if watchpoints and breakpoints share
same slots
- create all possible watchpoints on cpu 0
- change one of it to breakpoint
- in case wp and bp do not share slots,
we create another watchpoint to ensure
the slot accounting is correct

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/perf/tests/Build | 1 +
tools/perf/tests/bp_account.c | 195 ++++++++++++++++++++++++++++++++++++++++
tools/perf/tests/builtin-test.c | 4 +
tools/perf/tests/tests.h | 1 +
4 files changed, 201 insertions(+)
create mode 100644 tools/perf/tests/bp_account.c

diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index 87bf3edb037c..62ca0174d5e1 100644
--- a/tools/perf/tests/Build
+++ b/tools/perf/tests/Build
@@ -20,6 +20,7 @@ perf-y += hists_cumulate.o
perf-y += python-use.o
perf-y += bp_signal.o
perf-y += bp_signal_overflow.o
+perf-y += bp_account.o
perf-y += task-exit.o
perf-y += sw-clock.o
perf-y += mmap-thread-lookup.o
diff --git a/tools/perf/tests/bp_account.c b/tools/perf/tests/bp_account.c
new file mode 100644
index 000000000000..2f75fa0c4fef
--- /dev/null
+++ b/tools/perf/tests/bp_account.c
@@ -0,0 +1,195 @@
+/*
+ * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
+ * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
+ */
+#define __SANE_USERSPACE_TYPES__
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <time.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include <linux/compiler.h>
+#include <linux/hw_breakpoint.h>
+#include <sys/ioctl.h>
+
+#include "tests.h"
+#include "debug.h"
+#include "perf.h"
+#include "cloexec.h"
+
+volatile long the_var;
+
+static noinline int test_function(void)
+{
+ return 0;
+}
+
+static int __event(bool is_x, void *addr, struct perf_event_attr *attr)
+{
+ int fd;
+
+ memset(attr, 0, sizeof(struct perf_event_attr));
+ attr->type = PERF_TYPE_BREAKPOINT;
+ attr->size = sizeof(struct perf_event_attr);
+
+ attr->config = 0;
+ attr->bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
+ attr->bp_addr = (unsigned long) addr;
+ attr->bp_len = sizeof(long);
+
+ attr->sample_period = 1;
+ attr->sample_type = PERF_SAMPLE_IP;
+
+ attr->exclude_kernel = 1;
+ attr->exclude_hv = 1;
+
+ fd = sys_perf_event_open(attr, -1, 0, -1,
+ perf_event_open_cloexec_flag());
+ if (fd < 0) {
+ pr_debug("failed opening event %llx\n", attr->config);
+ return TEST_FAIL;
+ }
+
+ return fd;
+}
+
+static int wp_event(void *addr, struct perf_event_attr *attr)
+{
+ return __event(false, addr, attr);
+}
+
+static int bp_event(void *addr, struct perf_event_attr *attr)
+{
+ return __event(true, addr, attr);
+}
+
+static int bp_accounting(int wp_cnt, int share)
+{
+ struct perf_event_attr attr, attr_mod, attr_new;
+ int i, fd[wp_cnt], fd_wp, ret;
+
+ for (i = 0; i < wp_cnt; i++) {
+ fd[i] = wp_event((void *)&the_var, &attr);
+ TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
+ pr_debug("wp %d created\n", i);
+ }
+
+ attr_mod = attr;
+ attr_mod.bp_type = HW_BREAKPOINT_X;
+ attr_mod.bp_addr = (unsigned long) test_function;
+
+ ret = ioctl(fd[0], PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr_mod);
+ TEST_ASSERT_VAL("failed to modify wp\n", ret == 0);
+
+ pr_debug("wp 0 modified to bp\n");
+
+ if (!share) {
+ fd_wp = wp_event((void *)&the_var, &attr_new);
+ TEST_ASSERT_VAL("failed to create max wp\n", fd_wp != -1);
+ pr_debug("wp max created\n");
+ }
+
+ for (i = 0; i < wp_cnt; i++)
+ close(fd[i]);
+
+ return 0;
+}
+
+static int detect_cnt(bool is_x)
+{
+ struct perf_event_attr attr;
+ void *addr = is_x ? test_function : (void *) &the_var;
+ int fd[100], cnt = 0, i;
+
+ while (1) {
+ fd[cnt] = __event(is_x, addr, &attr);
+
+ if (fd[cnt] < 0)
+ break;
+
+ if (cnt == 100) {
+ pr_debug("way too many debug registers, fix the test\n");
+ return 0;
+ }
+
+ cnt++;
+ }
+
+ for (i = 0; i < cnt; i++)
+ close(fd[i]);
+
+ return cnt;
+}
+
+static int detect_ioctl(void)
+{
+ struct perf_event_attr attr;
+ int fd, ret = 1;
+
+ fd = wp_event((void *) &the_var, &attr);
+ if (fd > 0) {
+ ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr);
+ close(fd);
+ }
+
+ return ret ? 0 : 1;
+}
+
+static int detect_share(int wp_cnt, int bp_cnt)
+{
+ struct perf_event_attr attr;
+ int i, fd[wp_cnt + bp_cnt], ret;
+
+ for (i = 0; i < wp_cnt; i++) {
+ fd[i] = wp_event((void *)&the_var, &attr);
+ TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
+ }
+
+ for (; i < (bp_cnt + wp_cnt); i++) {
+ fd[i] = bp_event((void *)test_function, &attr);
+ if (fd[i] == -1)
+ break;
+ }
+
+ ret = i != (bp_cnt + wp_cnt);
+
+ while (i--)
+ close(fd[i]);
+
+ return ret;
+}
+
+/*
+ * This test does following:
+ * - detects the number of watch/break-points,
+ * skip test if any is missing
+ * - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
+ * skip test if it's missing
+ * - detects if watchpoints and breakpoints share
+ * same slots
+ * - create all possible watchpoints on cpu 0
+ * - change one of it to breakpoint
+ * - in case wp and bp do not share slots,
+ * we create another watchpoint to ensure
+ * the slot accounting is correct
+ */
+int test__bp_accounting(struct test *test __maybe_unused, int subtest __maybe_unused)
+{
+ int has_ioctl = detect_ioctl();
+ int wp_cnt = detect_cnt(false);
+ int bp_cnt = detect_cnt(true);
+ int share = detect_share(wp_cnt, bp_cnt);
+
+ pr_debug("watchpoints count %d, breakpoints count %d, has_ioctl %d, share %d\n",
+ wp_cnt, bp_cnt, has_ioctl, share);
+
+ if (!wp_cnt || !bp_cnt || !has_ioctl)
+ return TEST_SKIP;
+
+ return bp_accounting(wp_cnt, share);
+}
diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 766573e236e4..705558805a8c 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -116,6 +116,10 @@ static struct test generic_tests[] = {
.is_supported = test__bp_signal_is_supported,
},
{
+ .desc = "Breakpoint accounting",
+ .func = test__bp_accounting,
+ },
+ {
.desc = "Number of exit events of a simple workload",
.func = test__task_exit,
},
diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
index 2862b80bc288..9f51edac44ae 100644
--- a/tools/perf/tests/tests.h
+++ b/tools/perf/tests/tests.h
@@ -58,6 +58,7 @@ int test__hists_link(struct test *test, int subtest);
int test__python_use(struct test *test, int subtest);
int test__bp_signal(struct test *test, int subtest);
int test__bp_signal_overflow(struct test *test, int subtest);
+int test__bp_accounting(struct test *test, int subtest);
int test__task_exit(struct test *test, int subtest);
int test__mem(struct test *test, int subtest);
int test__sw_clock_freq(struct test *test, int subtest);
--
2.13.6
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