drm: Add some kselftests for the DRM range manager (struct drm_mm)

First we introduce a smattering of infrastructure for writing selftests.
The idea is that we have a test module that exercises a particular
portion of the exported API, and that module provides a set of tests
that can either be run as an ensemble via kselftest or individually via
an igt harness (in this case igt/drm_mm). To accommodate selecting
individual tests, we export a boolean parameter to control selection of
each test - that is hidden inside a bunch of reusable boilerplate macros
to keep writing the tests simple.

v2: Choose a random random_seed unless one is specified by the user.
v3: More parameters to control max_iterations and max_prime of the
tests.

Testcase: igt/drm_mm
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161222083641.2691-7-chris@chris-wilson.co.uk

drivers/gpu/drm/Kconfig

@@ -48,6 +48,21 @@ config DRM_DEBUG_MM
 
 	  If in doubt, say "N".
 
+config DRM_DEBUG_MM_SELFTEST
+	tristate "kselftests for DRM range manager (struct drm_mm)"
+	depends on DRM
+	depends on DEBUG_KERNEL
+	select PRIME_NUMBERS
+	select DRM_LIB_RANDOM
+	default n
+	help
+	  This option provides a kernel module that can be used to test
+	  the DRM range manager (drm_mm) and its API. This option is not
+	  useful for distributions or general kernels, but only for kernel
+	  developers working on DRM and associated drivers.
+
+	  If in doubt, say "N".
+
 config DRM_KMS_HELPER
 	tristate
 	depends on DRM

drivers/gpu/drm/Makefile

@@ -38,6 +38,7 @@ drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
 drm_kms_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o
 
 obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
+obj-$(CONFIG_DRM_DEBUG_MM_SELFTEST) += selftests/test-drm_mm.o
 
 CFLAGS_drm_trace_points.o := -I$(src)
 

drivers/gpu/drm/selftests/drm_mm_selftests.h

@@ -0,0 +1,8 @@
+/* List each unit test as selftest(name, function)
+ *
+ * The name is used as both an enum and expanded as igt__name to create
+ * a module parameter. It must be unique and legal for a C identifier.
+ *
+ * Tests are executed in order by igt/drm_mm
+ */
+selftest(sanitycheck, igt_sanitycheck) /* keep first (selfcheck for igt) */

drivers/gpu/drm/selftests/drm_selftest.c

@@ -0,0 +1,109 @@
+/*
+ * Copyright © 2016 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 <linux/compiler.h>
+
+#define selftest(name, func) __idx_##name,
+enum {
+#include TESTS
+};
+#undef selftest
+
+#define selftest(n, f) [__idx_##n] = { .name = #n, .func = f },
+static struct drm_selftest {
+	bool enabled;
+	const char *name;
+	int (*func)(void *);
+} selftests[] = {
+#include TESTS
+};
+#undef selftest
+
+/* Embed the line number into the parameter name so that we can order tests */
+#define param(n) __PASTE(igt__, __PASTE(__PASTE(__LINE__, __), n))
+#define selftest_0(n, func, id) \
+module_param_named(id, selftests[__idx_##n].enabled, bool, 0400);
+#define selftest(n, func) selftest_0(n, func, param(n))
+#include TESTS
+#undef selftest
+
+static void set_default_test_all(struct drm_selftest *st, unsigned long count)
+{
+	unsigned long i;
+
+	for (i = 0; i < count; i++)
+		if (st[i].enabled)
+			return;
+
+	for (i = 0; i < count; i++)
+		st[i].enabled = true;
+}
+
+static int run_selftests(struct drm_selftest *st,
+			 unsigned long count,
+			 void *data)
+{
+	int err = 0;
+
+	set_default_test_all(st, count);
+
+	/* Tests are listed in natural order in drm_*_selftests.h */
+	for (; count--; st++) {
+		if (!st->enabled)
+			continue;
+
+		pr_debug("drm: Running %s\n", st->name);
+		err = st->func(data);
+		if (err)
+			break;
+	}
+
+	if (WARN(err > 0 || err == -ENOTTY,
+		 "%s returned %d, conflicting with selftest's magic values!\n",
+		 st->name, err))
+		err = -1;
+
+	rcu_barrier();
+	return err;
+}
+
+static int __maybe_unused
+__drm_subtests(const char *caller,
+	       const struct drm_subtest *st,
+	       int count,
+	       void *data)
+{
+	int err;
+
+	for (; count--; st++) {
+		pr_debug("Running %s/%s\n", caller, st->name);
+		err = st->func(data);
+		if (err) {
+			pr_err("%s: %s failed with error %d\n",
+			       caller, st->name, err);
+			return err;
+		}
+	}
+
+	return 0;
+}

drivers/gpu/drm/selftests/drm_selftest.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright © 2016 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 __DRM_SELFTEST_H__
+#define __DRM_SELFTEST_H__
+
+struct drm_subtest {
+	int (*func)(void *data);
+	const char *name;
+};
+
+static int __drm_subtests(const char *caller,
+			  const struct drm_subtest *st,
+			  int count,
+			  void *data);
+#define drm_subtests(T, data) \
+	__drm_subtests(__func__, T, ARRAY_SIZE(T), data)
+
+#define SUBTEST(x) { x, #x }
+
+#endif /* __DRM_SELFTEST_H__ */

drivers/gpu/drm/selftests/test-drm_mm.c

@@ -0,0 +1,58 @@
+/*
+ * Test cases for the drm_mm range manager
+ */
+
+#define pr_fmt(fmt) "drm_mm: " fmt
+
+#include <linux/module.h>
+#include <linux/prime_numbers.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/vmalloc.h>
+
+#include <drm/drm_mm.h>
+
+#include "../lib/drm_random.h"
+
+#define TESTS "drm_mm_selftests.h"
+#include "drm_selftest.h"
+
+static unsigned int random_seed;
+static unsigned int max_iterations = 8192;
+static unsigned int max_prime = 128;
+
+static int igt_sanitycheck(void *ignored)
+{
+	pr_info("%s - ok!\n", __func__);
+	return 0;
+}
+
+#include "drm_selftest.c"
+
+static int __init test_drm_mm_init(void)
+{
+	int err;
+
+	while (!random_seed)
+		random_seed = get_random_int();
+
+	pr_info("Testing DRM range manger (struct drm_mm), with random_seed=0x%x max_iterations=%u max_prime=%u\n",
+		random_seed, max_iterations, max_prime);
+	err = run_selftests(selftests, ARRAY_SIZE(selftests), NULL);
+
+	return err > 0 ? 0 : err;
+}
+
+static void __exit test_drm_mm_exit(void)
+{
+}
+
+module_init(test_drm_mm_init);
+module_exit(test_drm_mm_exit);
+
+module_param(random_seed, uint, 0400);
+module_param(max_iterations, uint, 0400);
+module_param(max_prime, uint, 0400);
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL");

tools/testing/selftests/drivers/gpu/drm_mm.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+# Runs API tests for struct drm_mm (DRM range manager)
+
+if ! /sbin/modprobe -n -q test-drm_mm; then
+       echo "drivers/gpu/drm_mm: [skip]"
+       exit 77
+fi
+
+if /sbin/modprobe -q test-drm_mm; then
+       /sbin/modprobe -q -r test-drm_mm
+       echo "drivers/gpu/drm_mm: ok"
+else
+       echo "drivers/gpu/drm_mm: [FAIL]"
+       exit 1
+fi