[igt-dev] [PATCH i-g-t 1/2] lib: Add hooks for enabling ftrace

* [igt-dev] [PATCH i-g-t 1/2] lib: Add hooks for enabling ftrace
@ 2019-03-16  9:25 Chris Wilson
  2019-03-16  9:25 ` [igt-dev] [PATCH i-g-t 2/2] i915/pm_rpm: Enable ftrace logging Chris Wilson
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Chris Wilson @ 2019-03-16  9:25 UTC (permalink / raw)
  To: igt-dev

If the kernel has tracing support builtin, we can enable around
troublesome tests to obtain greater detail from the kernel that may
prove invaluable in debugging the problem.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 lib/Makefile.sources |   2 +
 lib/igt_core.c       |  28 ++----
 lib/igt_ftrace.c     | 204 +++++++++++++++++++++++++++++++++++++++++++
 lib/igt_ftrace.h     |  46 ++++++++++
 lib/meson.build      |   1 +
 5 files changed, 258 insertions(+), 23 deletions(-)
 create mode 100644 lib/igt_ftrace.c
 create mode 100644 lib/igt_ftrace.h

diff --git a/lib/Makefile.sources b/lib/Makefile.sources
index cf2720981..24ee5f094 100644
--- a/lib/Makefile.sources
+++ b/lib/Makefile.sources
@@ -26,6 +26,8 @@ lib_source_list =	 	\
 	igt_color_encoding.c	\
 	igt_color_encoding.h	\
 	igt_edid_template.h	\
+	igt_ftrace.c		\
+	igt_ftrace.h		\
 	igt_gt.c		\
 	igt_gt.h		\
 	igt_gvt.c		\
diff --git a/lib/igt_core.c b/lib/igt_core.c
index 6eb4798e2..3e69cf66c 100644
--- a/lib/igt_core.c
+++ b/lib/igt_core.c
@@ -62,6 +62,7 @@
 #include "intel_io.h"
 #include "igt_debugfs.h"
 #include "igt_dummyload.h"
+#include "igt_ftrace.h"
 #include "version.h"
 #include "config.h"
 
@@ -490,31 +491,11 @@ void __igt_fixture_end(void)
 	siglongjmp(igt_subtest_jmpbuf, 1);
 }
 
-/*
- * If the test takes out the machine, in addition to the usual dmesg
- * spam, the kernel may also emit a "death rattle" -- extra debug
- * information that is overkill for normal successful tests, but
- * vital for post-mortem analysis.
- */
-static void ftrace_dump_on_oops(bool enable)
-{
-	int fd;
-
-	fd = open("/proc/sys/kernel/ftrace_dump_on_oops", O_WRONLY);
-	if (fd < 0)
-		return;
-
-	/*
-	 * If we fail, we do not get the death rattle we wish, but we
-	 * still want to run the tests anyway.
-	 */
-	igt_ignore_warn(write(fd, enable ? "1\n" : "0\n", 2));
-	close(fd);
-}
-
 bool igt_exit_called;
 static void common_exit_handler(int sig)
 {
+	igt_ftrace_close();
+
 	if (!igt_only_list_subtests()) {
 		bind_fbcon(true);
 	}
@@ -812,7 +793,8 @@ out:
 
 		sync();
 		oom_adjust_for_doom();
-		ftrace_dump_on_oops(true);
+
+		igt_ftrace_open();
 	}
 
 	/* install exit handler, to ensure we clean up */
diff --git a/lib/igt_ftrace.c b/lib/igt_ftrace.c
new file mode 100644
index 000000000..428b35132
--- /dev/null
+++ b/lib/igt_ftrace.c
@@ -0,0 +1,204 @@
+/*
+ * Copyright © 2017 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "igt.h"
+#include "igt_ftrace.h"
+#include "igt_debugfs.h"
+#include "igt_sysfs.h"
+
+#define BIT(x) (1ul << (x))
+
+/* Only a single tracer in the kernel, so we can use a singleton */
+struct igt_ftrace {
+	int dir;
+
+	unsigned long flags;
+#define PID_SET BIT(0)
+#define INCLUDE_SET BIT(1)
+#define EXCLUDE_SET BIT(2)
+
+} igt_ftrace = { -1 };
+
+/*
+ * If the test takes out the machine, in addition to the usual dmesg
+ * spam, the kernel may also emit a "death rattle" -- extra debug
+ * information that is overkill for normal successful tests, but
+ * vital for post-mortem analysis.
+ */
+static void ftrace_dump_on_oops(bool enable)
+{
+	int fd;
+
+	fd = open("/proc/sys/kernel/ftrace_dump_on_oops", O_WRONLY);
+	if (fd < 0)
+		return;
+
+	/*
+	 * If we fail, we do not get the death rattle we wish, but we
+	 * still want to run the tests anyway.
+	 */
+	igt_ignore_warn(write(fd, enable ? "1\n" : "0\n", 2));
+	close(fd);
+}
+
+int igt_ftrace_open(void)
+{
+	int dir;
+	int err;
+
+	dir = open(igt_debugfs_mount(), O_RDONLY);
+	if (dir < 0)
+		return -errno;
+
+	igt_ftrace.dir = openat(dir, "tracing", O_RDONLY);
+	close(dir);
+	if (igt_ftrace.dir < 0)
+		return -errno;
+
+	err = igt_ftrace_disable();
+	if (err)
+		goto ft_close;
+
+	ftrace_dump_on_oops(true);
+	return 0;
+
+ft_close:
+	close(igt_ftrace.dir);
+	igt_ftrace.dir = -1;
+	return err;
+}
+
+int __igt_ftrace_enable(const char *mode,
+			const struct igt_ftrace_options *opts)
+{
+	int err;
+
+	if (igt_ftrace.dir < 0)
+		return -ENODEV;
+
+	if (!mode)
+		return -EINVAL;
+
+	err = igt_sysfs_set(igt_ftrace.dir, "current_tracer", mode);
+	if (err < 0)
+		return err;
+
+	if (opts && opts->pid) {
+		err = igt_sysfs_printf(igt_ftrace.dir,
+				       "set_ftrace_pid", "%d",
+				       opts->pid);
+		if (err < 0)
+			goto disable;
+
+		igt_ftrace.flags |= PID_SET;
+	}
+
+	if (opts && opts->include) {
+		err = igt_sysfs_set(igt_ftrace.dir,
+				    "set_ftrace_filter",
+				    opts->include);
+		if (err < 0)
+			goto disable;
+
+		igt_ftrace.flags |= INCLUDE_SET;
+	}
+
+	if (opts && opts->exclude) {
+		err = igt_sysfs_set(igt_ftrace.dir,
+				    "set_ftrace_notrace",
+				    opts->exclude);
+		if (err < 0)
+			goto disable;
+
+		igt_ftrace.flags |= EXCLUDE_SET;
+	}
+
+	err = igt_sysfs_set(igt_ftrace.dir, "tracer_on", "1");
+	if (err < 0)
+		return err;
+
+	return 0;
+
+disable:
+	igt_ftrace_disable();
+	return err;
+}
+
+int igt_ftrace_disable(void)
+{
+	int err;
+
+	if (igt_ftrace.dir < 0)
+		return -ENODEV;
+
+	err = igt_sysfs_set(igt_ftrace.dir, "tracer_on", "0");
+	if (err < 0)
+		return err;
+
+	if (igt_ftrace.flags & PID_SET) {
+		igt_sysfs_set(igt_ftrace.dir, "set_ftrace_pid", "");
+		igt_ftrace.flags &= ~PID_SET;
+	}
+
+	if (igt_ftrace.flags & INCLUDE_SET) {
+		igt_sysfs_set(igt_ftrace.dir, "set_ftrace_filter", "");
+		igt_ftrace.flags &= ~INCLUDE_SET;
+	}
+
+	if (igt_ftrace.flags & EXCLUDE_SET) {
+		igt_sysfs_set(igt_ftrace.dir, "set_ftrace_notrace", "");
+		igt_ftrace.flags &= ~EXCLUDE_SET;
+	}
+
+	return 0;
+}
+
+void igt_ftrace_dump(const char *header)
+{
+	char *txt;
+
+	if (igt_ftrace.dir < 0)
+		return;
+
+	txt = igt_sysfs_get(igt_ftrace.dir, "trace");
+	if (!txt)
+		return;
+
+	igt_info("%s:\n%s", header, txt);
+	free(txt);
+}
+
+void igt_ftrace_close(void)
+{
+	if (igt_ftrace.dir < 0)
+		return;
+
+	close(igt_ftrace.dir);
+	igt_ftrace.dir = -1;
+}
diff --git a/lib/igt_ftrace.h b/lib/igt_ftrace.h
new file mode 100644
index 000000000..3dd676829
--- /dev/null
+++ b/lib/igt_ftrace.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright © 2017 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef IGT_FTRACE_H
+#define IGT_FTRACE_H
+
+int igt_ftrace_open(void);
+
+struct igt_ftrace_options {
+	int pid;
+	const char *include;
+	const char *exclude;
+};
+
+int __igt_ftrace_enable(const char *mode,
+			const struct igt_ftrace_options *opts);
+#define igt_ftrace_enable() __igt_ftrace_enable("function_graph", NULL)
+
+int igt_ftrace_disable(void);
+
+void igt_ftrace_dump(const char *header);
+
+void igt_ftrace_close(void);
+
+#endif /* IGT_FTRACE_H */
diff --git a/lib/meson.build b/lib/meson.build
index 0eb5585d7..2f0f65a08 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -9,6 +9,7 @@ lib_sources = [
 	'igt_debugfs.c',
 	'igt_device.c',
 	'igt_aux.c',
+	'igt_ftrace.c',
 	'igt_gt.c',
 	'igt_gvt.c',
 	'igt_matrix.c',
-- 
2.20.1

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