Commit-ID:  5acc575fec9f424f0b557844dbda8aed57baae1e
Gitweb:     https://git.kernel.org/tip/5acc575fec9f424f0b557844dbda8aed57baae1e
Author:     Jiri Olsa <jo...@kernel.org>
AuthorDate: Mon, 12 Mar 2018 14:45:48 +0100
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Tue, 13 Mar 2018 06:56:09 +0100

perf tests: Add breakpoint accounting/modify test

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 <jo...@kernel.org>
Cc: Alexander Shishkin <alexander.shish...@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: David Ahern <dsah...@gmail.com>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Hari Bathini <hbath...@linux.vnet.ibm.com>
Cc: Jin Yao <yao....@linux.intel.com>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Kan Liang <kan.li...@intel.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Milind Chabbi <chabbi.mil...@gmail.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Oleg Nesterov <onest...@redhat.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Will Deacon <will.dea...@arm.com>
Link: http://lkml.kernel.org/r/20180312134548.31532-9-jo...@kernel.org
Signed-off-by: Ingo Molnar <mi...@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(+)

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 fafa014240cd..38bf109ce106 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -115,6 +115,10 @@ static struct test generic_tests[] = {
                .func = test__bp_signal_overflow,
                .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);

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