[PATCH] perf test: Implement skip_reason callback for watchpoint tests

[Tommi Rantala]

Currently reason for skipping the read only watchpoint test is only seen
when running in verbose mode:

  $ perf test watchpoint
  23: Watchpoint                                            :
  23.1: Read Only Watchpoint                                : Skip
  23.2: Write Only Watchpoint                               : Ok
  23.3: Read / Write Watchpoint                             : Ok
  23.4: Modify Watchpoint                                   : Ok

  $ perf test -v watchpoint
  23: Watchpoint                                            :
  23.1: Read Only Watchpoint                                :
  --- start ---
  test child forked, pid 60204
  Hardware does not support read only watchpoints.
  test child finished with -2

Implement skip_reason callback for the watchpoint tests, so that it's
easy to see reason why the test is skipped:

  $ perf test watchpoint
  23: Watchpoint                                            :
  23.1: Read Only Watchpoint                                : Skip (missing 
hardware support)
  23.2: Write Only Watchpoint                               : Ok
  23.3: Read / Write Watchpoint                             : Ok
  23.4: Modify Watchpoint                                   : Ok

Signed-off-by: Tommi Rantala <tommi.t.rant...@nokia.com>
---
 tools/perf/tests/builtin-test.c |  1 +
 tools/perf/tests/tests.h        |  1 +
 tools/perf/tests/wp.c           | 21 +++++++++++++++------
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index d328caaba45d..3bfad4ee31ae 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -142,6 +142,7 @@ static struct test generic_tests[] = {
                        .skip_if_fail   = false,
                        .get_nr         = test__wp_subtest_get_nr,
                        .get_desc       = test__wp_subtest_get_desc,
+                       .skip_reason    = test__wp_subtest_skip_reason,
                },
        },
        {
diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
index 4447a516c689..0630301087a6 100644
--- a/tools/perf/tests/tests.h
+++ b/tools/perf/tests/tests.h
@@ -66,6 +66,7 @@ int test__bp_signal_overflow(struct test *test, int subtest);
 int test__bp_accounting(struct test *test, int subtest);
 int test__wp(struct test *test, int subtest);
 const char *test__wp_subtest_get_desc(int subtest);
+const char *test__wp_subtest_skip_reason(int subtest);
 int test__wp_subtest_get_nr(void);
 int test__task_exit(struct test *test, int subtest);
 int test__mem(struct test *test, int subtest);
diff --git a/tools/perf/tests/wp.c b/tools/perf/tests/wp.c
index d262d6639829..9387fa76faa5 100644
--- a/tools/perf/tests/wp.c
+++ b/tools/perf/tests/wp.c
@@ -174,10 +174,12 @@ static bool wp_ro_supported(void)
 #endif
 }
 
-static void wp_ro_skip_msg(void)
+static const char *wp_ro_skip_msg(void)
 {
 #if defined (__x86_64__) || defined (__i386__)
-       pr_debug("Hardware does not support read only watchpoints.\n");
+       return "missing hardware support";
+#else
+       return NULL;
 #endif
 }
 
@@ -185,7 +187,7 @@ static struct {
        const char *desc;
        int (*target_func)(void);
        bool (*is_supported)(void);
-       void (*skip_msg)(void);
+       const char *(*skip_msg)(void);
 } wp_testcase_table[] = {
        {
                .desc = "Read Only Watchpoint",
@@ -219,16 +221,23 @@ const char *test__wp_subtest_get_desc(int i)
        return wp_testcase_table[i].desc;
 }
 
+const char *test__wp_subtest_skip_reason(int i)
+{
+       if (i < 0 || i >= (int)ARRAY_SIZE(wp_testcase_table))
+               return NULL;
+       if (!wp_testcase_table[i].skip_msg)
+               return NULL;
+       return wp_testcase_table[i].skip_msg();
+}
+
 int test__wp(struct test *test __maybe_unused, int i)
 {
        if (i < 0 || i >= (int)ARRAY_SIZE(wp_testcase_table))
                return TEST_FAIL;
 
        if (wp_testcase_table[i].is_supported &&
-           !wp_testcase_table[i].is_supported()) {
-               wp_testcase_table[i].skip_msg();
+           !wp_testcase_table[i].is_supported())
                return TEST_SKIP;
-       }
 
        return !wp_testcase_table[i].target_func() ? TEST_OK : TEST_FAIL;
 }
-- 
2.26.2