Merge tag 'linux_kselftest-kunit-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull KUnit updates from Shuah Khan:

 - a new feature that adds APIs for managing devices introducing a set
   of helper functions which allow devices (internally a struct
   kunit_device) to be created and managed by KUnit.

   These devices will be automatically unregistered on test exit. These
   helpers can either use a user-provided struct device_driver, or have
   one automatically created and managed by KUnit. In both cases, the
   device lives on a new kunit_bus.

 - changes to switch drm/tests to use kunit devices

 - several fixes and enhancements to attribute feature

 - changes to reorganize deferred action function introducing
   KUNIT_DEFINE_ACTION_WRAPPER

 - new feature adds ability to run tests after boot using debugfs

 - fixes and enhancements to string-stream-test:
     - parse ERR_PTR in string_stream_destroy()
     - unchecked dereference in bug fix in debugfs_print_results()
     - handling errors from alloc_string_stream()
     - NULL-dereference bug fix in kunit_init_suite()

* tag 'linux_kselftest-kunit-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (27 commits)
  kunit: Fix some comments which were mistakenly kerneldoc
  kunit: Protect string comparisons against NULL
  kunit: Add example of kunit_activate_static_stub() with pointer-to-function
  kunit: Allow passing function pointer to kunit_activate_static_stub()
  kunit: Fix NULL-dereference in kunit_init_suite() if suite->log is NULL
  kunit: Reset test->priv after each param iteration
  kunit: Add example for using test->priv
  drm/tests: Switch to kunit devices
  ASoC: topology: Replace fake root_device with kunit_device in tests
  overflow: Replace fake root_device with kunit_device
  fortify: test: Use kunit_device
  kunit: Add APIs for managing devices
  Documentation: Add debugfs docs with run after boot
  kunit: add ability to run tests after boot using debugfs
  kunit: add is_init test attribute
  kunit: add example suite to test init suites
  kunit: add KUNIT_INIT_TABLE to init linker section
  kunit: move KUNIT_TABLE out of INIT_DATA
  kunit: tool: add test for parsing attributes
  kunit: tool: fix parsing of test attributes
  ...

Documentation/dev-tools/kunit/api/resource.rst

@@ -11,3 +11,12 @@ state on a per-test basis, register custom cleanup actions, and more.
 
 .. kernel-doc:: include/kunit/resource.h
    :internal:
+
+Managed Devices
+---------------
+
+Functions for using KUnit-managed struct device and struct device_driver.
+Include ``kunit/device.h`` to use these.
+
+.. kernel-doc:: include/kunit/device.h
+   :internal:

Documentation/dev-tools/kunit/run_manual.rst

@@ -49,9 +49,52 @@ loaded.
 
 The results will appear in TAP format in ``dmesg``.
 
+debugfs
+=======
+
+KUnit can be accessed from userspace via the debugfs filesystem (See more
+information about debugfs at Documentation/filesystems/debugfs.rst).
+
+If ``CONFIG_KUNIT_DEBUGFS`` is enabled, the KUnit debugfs filesystem is
+mounted at /sys/kernel/debug/kunit. You can use this filesystem to perform
+the following actions.
+
+Retrieve Test Results
+=====================
+
+You can use debugfs to retrieve KUnit test results. The test results are
+accessible from the debugfs filesystem in the following read-only file:
+
+.. code-block :: bash
+
+	/sys/kernel/debug/kunit/<test_suite>/results
+
+The test results are printed in a KTAP document. Note this document is separate
+to the kernel log and thus, may have different test suite numbering.
+
+Run Tests After Kernel Has Booted
+=================================
+
+You can use the debugfs filesystem to trigger built-in tests to run after
+boot. To run the test suite, you can use the following command to write to
+the ``/sys/kernel/debug/kunit/<test_suite>/run`` file:
+
+.. code-block :: bash
+
+	echo "any string" > /sys/kernel/debugfs/kunit/<test_suite>/run
+
+As a result, the test suite runs and the results are printed to the kernel
+log.
+
+However, this feature is not available with KUnit suites that use init data,
+because init data may have been discarded after the kernel boots. KUnit
+suites that use init data should be defined using the
+kunit_test_init_section_suites() macro.
+
+Also, you cannot use this feature to run tests concurrently. Instead a test
+will wait to run until other tests have completed or failed.
+
 .. note ::
 
-	If ``CONFIG_KUNIT_DEBUGFS`` is enabled, KUnit test results will
-	be accessible from the ``debugfs`` filesystem (if mounted).
-	They will be in ``/sys/kernel/debug/kunit/<test_suite>/results``, in
-	TAP format.
+	For test authors, to use this feature, tests will need to correctly initialise
+	and/or clean up any data, so the test runs correctly a second time.

Documentation/dev-tools/kunit/running_tips.rst

@@ -428,3 +428,10 @@ This attribute indicates the name of the module associated with the test.
 
 This attribute is automatically saved as a string and is printed for each suite.
 Tests can also be filtered using this attribute.
+
+``is_init``
+
+This attribute indicates whether the test uses init data or functions.
+
+This attribute is automatically saved as a boolean and tests can also be
+filtered using this attribute.

Documentation/dev-tools/kunit/usage.rst

@@ -651,12 +651,16 @@ For example:
 	}
 
 Note that, for functions like device_unregister which only accept a single
-pointer-sized argument, it's possible to directly cast that function to
-a ``kunit_action_t`` rather than writing a wrapper function, for example:
+pointer-sized argument, it's possible to automatically generate a wrapper
+with the ``KUNIT_DEFINE_ACTION_WRAPPER()`` macro, for example:
 
 .. code-block:: C
 
-	kunit_add_action(test, (kunit_action_t *)&device_unregister, &dev);
+	KUNIT_DEFINE_ACTION_WRAPPER(device_unregister, device_unregister_wrapper, struct device *);
+	kunit_add_action(test, &device_unregister_wrapper, &dev);
+
+You should do this in preference to manually casting to the ``kunit_action_t`` type,
+as casting function pointers will break Control Flow Integrity (CFI).
 
 ``kunit_add_action`` can fail if, for example, the system is out of memory.
 You can use ``kunit_add_action_or_reset`` instead which runs the action
@@ -793,3 +797,53 @@ structures as shown below:
 KUnit is not enabled, or if no test is running in the current task, it will do
 nothing. This compiles down to either a no-op or a static key check, so will
 have a negligible performance impact when no test is running.
+
+Managing Fake Devices and Drivers
+---------------------------------
+
+When testing drivers or code which interacts with drivers, many functions will
+require a ``struct device`` or ``struct device_driver``. In many cases, setting
+up a real device is not required to test any given function, so a fake device
+can be used instead.
+
+KUnit provides helper functions to create and manage these fake devices, which
+are internally of type ``struct kunit_device``, and are attached to a special
+``kunit_bus``. These devices support managed device resources (devres), as
+described in Documentation/driver-api/driver-model/devres.rst
+
+To create a KUnit-managed ``struct device_driver``, use ``kunit_driver_create()``,
+which will create a driver with the given name, on the ``kunit_bus``. This driver
+will automatically be destroyed when the corresponding test finishes, but can also
+be manually destroyed with ``driver_unregister()``.
+
+To create a fake device, use the ``kunit_device_register()``, which will create
+and register a device, using a new KUnit-managed driver created with ``kunit_driver_create()``.
+To provide a specific, non-KUnit-managed driver, use ``kunit_device_register_with_driver()``
+instead. Like with managed drivers, KUnit-managed fake devices are automatically
+cleaned up when the test finishes, but can be manually cleaned up early with
+``kunit_device_unregister()``.
+
+The KUnit devices should be used in preference to ``root_device_register()``, and
+instead of ``platform_device_register()`` in cases where the device is not otherwise
+a platform device.
+
+For example:
+
+.. code-block:: c
+
+	#include <kunit/device.h>
+
+	static void test_my_device(struct kunit *test)
+	{
+		struct device *fake_device;
+		const char *dev_managed_string;
+
+		// Create a fake device.
+		fake_device = kunit_device_register(test, "my_device");
+		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fake_device)
+
+		// Pass it to functions which need a device.
+		dev_managed_string = devm_kstrdup(fake_device, "Hello, World!");
+
+		// Everything is cleaned up automatically when the test ends.
+	}

drivers/gpu/drm/tests/drm_kunit_helpers.c

@@ -5,6 +5,7 @@
 #include <drm/drm_kunit_helpers.h>
 #include <drm/drm_managed.h>
 
+#include <kunit/device.h>
 #include <kunit/resource.h>
 
 #include <linux/device.h>
@@ -15,40 +16,6 @@
 static const struct drm_mode_config_funcs drm_mode_config_funcs = {
 };
 
-static int fake_probe(struct platform_device *pdev)
-{
-	return 0;
-}
-
-static struct platform_driver fake_platform_driver = {
-	.probe	= fake_probe,
-	.driver = {
-		.name	= KUNIT_DEVICE_NAME,
-	},
-};
-
-static void kunit_action_platform_driver_unregister(void *ptr)
-{
-	struct platform_driver *drv = ptr;
-
-	platform_driver_unregister(drv);
-
-}
-
-static void kunit_action_platform_device_put(void *ptr)
-{
-	struct platform_device *pdev = ptr;
-
-	platform_device_put(pdev);
-}
-
-static void kunit_action_platform_device_del(void *ptr)
-{
-	struct platform_device *pdev = ptr;
-
-	platform_device_del(pdev);
-}
-
 /**
  * drm_kunit_helper_alloc_device - Allocate a mock device for a KUnit test
  * @test: The test context object
@@ -66,34 +33,7 @@ static void kunit_action_platform_device_del(void *ptr)
  */
 struct device *drm_kunit_helper_alloc_device(struct kunit *test)
 {
-	struct platform_device *pdev;
-	int ret;
-
-	ret = platform_driver_register(&fake_platform_driver);
-	KUNIT_ASSERT_EQ(test, ret, 0);
-
-	ret = kunit_add_action_or_reset(test,
-					kunit_action_platform_driver_unregister,
-					&fake_platform_driver);
-	KUNIT_ASSERT_EQ(test, ret, 0);
-
-	pdev = platform_device_alloc(KUNIT_DEVICE_NAME, PLATFORM_DEVID_NONE);
-	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
-
-	ret = kunit_add_action_or_reset(test,
-					kunit_action_platform_device_put,
-					pdev);
-	KUNIT_ASSERT_EQ(test, ret, 0);
-
-	ret = platform_device_add(pdev);
-	KUNIT_ASSERT_EQ(test, ret, 0);
-
-	ret = kunit_add_action_or_reset(test,
-					kunit_action_platform_device_del,
-					pdev);
-	KUNIT_ASSERT_EQ(test, ret, 0);
-
-	return &pdev->dev;
+	return kunit_device_register(test, KUNIT_DEVICE_NAME);
 }
 EXPORT_SYMBOL_GPL(drm_kunit_helper_alloc_device);
 
@@ -106,19 +46,7 @@ EXPORT_SYMBOL_GPL(drm_kunit_helper_alloc_device);
  */
 void drm_kunit_helper_free_device(struct kunit *test, struct device *dev)
 {
-	struct platform_device *pdev = to_platform_device(dev);
-
-	kunit_release_action(test,
-			     kunit_action_platform_device_del,
-			     pdev);
-
-	kunit_release_action(test,
-			     kunit_action_platform_device_put,
-			     pdev);
-
-	kunit_release_action(test,
-			     kunit_action_platform_driver_unregister,
-			     &fake_platform_driver);
+	kunit_device_unregister(test, dev);
 }
 EXPORT_SYMBOL_GPL(drm_kunit_helper_free_device);
 

drivers/gpu/drm/vc4/tests/vc4_mock.c

@@ -153,12 +153,9 @@ static int __build_mock(struct kunit *test, struct drm_device *drm,
 	return 0;
 }
 
-static void kunit_action_drm_dev_unregister(void *ptr)
-{
-	struct drm_device *drm = ptr;
-
-	drm_dev_unregister(drm);
-}
+KUNIT_DEFINE_ACTION_WRAPPER(kunit_action_drm_dev_unregister,
+			    drm_dev_unregister,
+			    struct drm_device *);
 
 static struct vc4_dev *__mock_device(struct kunit *test, bool is_vc5)
 {

include/asm-generic/vmlinux.lds.h

@@ -370,7 +370,8 @@
 	BRANCH_PROFILE()						\
 	TRACE_PRINTKS()							\
 	BPF_RAW_TP()							\
-	TRACEPOINT_STR()
+	TRACEPOINT_STR()						\
+	KUNIT_TABLE()
 
 /*
  * Data section helpers
@@ -700,7 +701,7 @@
 	EARLYCON_TABLE()						\
 	LSM_TABLE()							\
 	EARLY_LSM_TABLE()						\
-	KUNIT_TABLE()
+	KUNIT_INIT_TABLE()
 
 #define INIT_TEXT							\
 	*(.init.text .init.text.*)					\
@@ -926,6 +927,12 @@
 		. = ALIGN(8);						\
 		BOUNDED_SECTION_POST_LABEL(.kunit_test_suites, __kunit_suites, _start, _end)
 
+/* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */
+#define KUNIT_INIT_TABLE()						\
+		. = ALIGN(8);						\
+		BOUNDED_SECTION_POST_LABEL(.kunit_init_test_suites, \
+				__kunit_init_suites, _start, _end)
+
 #ifdef CONFIG_BLK_DEV_INITRD
 #define INIT_RAM_FS							\
 	. = ALIGN(4);							\

include/kunit/device.h

@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KUnit basic device implementation
+ *
+ * Helpers for creating and managing fake devices for KUnit tests.
+ *
+ * Copyright (C) 2023, Google LLC.
+ * Author: David Gow <davidgow@google.com>
+ */
+
+#ifndef _KUNIT_DEVICE_H
+#define _KUNIT_DEVICE_H
+
+#if IS_ENABLED(CONFIG_KUNIT)
+
+#include <kunit/test.h>
+
+struct device;
+struct device_driver;
+
+/**
+ * kunit_driver_create() - Create a struct device_driver attached to the kunit_bus
+ * @test: The test context object.
+ * @name: The name to give the created driver.
+ *
+ * Creates a struct device_driver attached to the kunit_bus, with the name @name.
+ * This driver will automatically be cleaned up on test exit.
+ *
+ * Return: a stub struct device_driver, managed by KUnit, with the name @name.
+ */
+struct device_driver *kunit_driver_create(struct kunit *test, const char *name);
+
+/**
+ * kunit_device_register() - Create a struct device for use in KUnit tests
+ * @test: The test context object.
+ * @name: The name to give the created device.
+ *
+ * Creates a struct kunit_device (which is a struct device) with the given name,
+ * and a corresponding driver. The device and driver will be cleaned up on test
+ * exit, or when kunit_device_unregister is called. See also
+ * kunit_device_register_with_driver, if you wish to provide your own
+ * struct device_driver.
+ *
+ * Return: a pointer to a struct device which will be cleaned up when the test
+ * exits, or an error pointer if the device could not be allocated or registered.
+ */
+struct device *kunit_device_register(struct kunit *test, const char *name);
+
+/**
+ * kunit_device_register_with_driver() - Create a struct device for use in KUnit tests
+ * @test: The test context object.
+ * @name: The name to give the created device.
+ * @drv: The struct device_driver to associate with the device.
+ *
+ * Creates a struct kunit_device (which is a struct device) with the given
+ * name, and driver. The device will be cleaned up on test exit, or when
+ * kunit_device_unregister is called. See also kunit_device_register, if you
+ * wish KUnit to create and manage a driver for you.
+ *
+ * Return: a pointer to a struct device which will be cleaned up when the test
+ * exits, or an error pointer if the device could not be allocated or registered.
+ */
+struct device *kunit_device_register_with_driver(struct kunit *test,
+						 const char *name,
+						 const struct device_driver *drv);
+
+/**
+ * kunit_device_unregister() - Unregister a KUnit-managed device
+ * @test: The test context object which created the device
+ * @dev: The device.
+ *
+ * Unregisters and destroys a struct device which was created with
+ * kunit_device_register or kunit_device_register_with_driver. If KUnit created
+ * a driver, cleans it up as well.
+ */
+void kunit_device_unregister(struct kunit *test, struct device *dev);
+
+#endif
+
+#endif

include/kunit/resource.h

@@ -390,6 +390,27 @@ void kunit_remove_resource(struct kunit *test, struct kunit_resource *res);
 /* A 'deferred action' function to be used with kunit_add_action. */
 typedef void (kunit_action_t)(void *);
 
+/**
+ * KUNIT_DEFINE_ACTION_WRAPPER() - Wrap a function for use as a deferred action.
+ *
+ * @wrapper: The name of the new wrapper function define.
+ * @orig: The original function to wrap.
+ * @arg_type: The type of the argument accepted by @orig.
+ *
+ * Defines a wrapper for a function which accepts a single, pointer-sized
+ * argument. This wrapper can then be passed to kunit_add_action() and
+ * similar. This should be used in preference to casting a function
+ * directly to kunit_action_t, as casting function pointers will break
+ * control flow integrity (CFI), leading to crashes.
+ */
+#define KUNIT_DEFINE_ACTION_WRAPPER(wrapper, orig, arg_type)	\
+	static void wrapper(void *in)				\
+	{							\
+		arg_type arg = (arg_type)in;			\
+		orig(arg);					\
+	}
+
+
 /**
  * kunit_add_action() - Call a function when the test ends.
  * @test: Test case to associate the action with.

include/kunit/static_stub.h

@@ -93,7 +93,7 @@ void __kunit_activate_static_stub(struct kunit *test,
  * The redirection can be disabled again with kunit_deactivate_static_stub().
  */
 #define kunit_activate_static_stub(test, real_fn_addr, replacement_addr) do {	\
-	typecheck_fn(typeof(&real_fn_addr), replacement_addr);			\
+	typecheck_fn(typeof(&replacement_addr), real_fn_addr);			\
 	__kunit_activate_static_stub(test, real_fn_addr, replacement_addr);	\
 } while (0)
 

include/kunit/test.h

@@ -253,6 +253,7 @@ struct kunit_suite {
 	struct dentry *debugfs;
 	struct string_stream *log;
 	int suite_init_err;
+	bool is_init;
 };
 
 /* Stores an array of suites, end points one past the end */
@@ -337,6 +338,9 @@ void __kunit_test_suites_exit(struct kunit_suite **suites, int num_suites);
 void kunit_exec_run_tests(struct kunit_suite_set *suite_set, bool builtin);
 void kunit_exec_list_tests(struct kunit_suite_set *suite_set, bool include_attr);
 
+struct kunit_suite_set kunit_merge_suite_sets(struct kunit_suite_set init_suite_set,
+		struct kunit_suite_set suite_set);
+
 #if IS_BUILTIN(CONFIG_KUNIT)
 int kunit_run_all_tests(void);
 #else
@@ -371,6 +375,11 @@ static inline int kunit_run_all_tests(void)
 
 #define kunit_test_suite(suite)	kunit_test_suites(&suite)
 
+#define __kunit_init_test_suites(unique_array, ...)			       \
+	static struct kunit_suite *unique_array[]			       \
+	__aligned(sizeof(struct kunit_suite *))				       \
+	__used __section(".kunit_init_test_suites") = { __VA_ARGS__ }
+
 /**
  * kunit_test_init_section_suites() - used to register one or more &struct
  *				      kunit_suite containing init functions or
@@ -378,21 +387,21 @@ static inline int kunit_run_all_tests(void)
  *
  * @__suites: a statically allocated list of &struct kunit_suite.
  *
- * This functions identically as kunit_test_suites() except that it suppresses
- * modpost warnings for referencing functions marked __init or data marked
- * __initdata; this is OK because currently KUnit only runs tests upon boot
- * during the init phase or upon loading a module during the init phase.
+ * This functions similar to kunit_test_suites() except that it compiles the
+ * list of suites during init phase.
  *
- * NOTE TO KUNIT DEVS: If we ever allow KUnit tests to be run after boot, these
- * tests must be excluded.
+ * This macro also suffixes the array and suite declarations it makes with
+ * _probe; so that modpost suppresses warnings about referencing init data
+ * for symbols named in this manner.
  *
- * The only thing this macro does that's different from kunit_test_suites is
- * that it suffixes the array and suite declarations it makes with _probe;
- * modpost suppresses warnings about referencing init data for symbols named in
- * this manner.
+ * Note: these init tests are not able to be run after boot so there is no
+ * "run" debugfs file generated for these tests.
+ *
+ * Also, do not mark the suite or test case structs with __initdata because
+ * they will be used after the init phase with debugfs.
  */
 #define kunit_test_init_section_suites(__suites...)			\
-	__kunit_test_suites(CONCATENATE(__UNIQUE_ID(array), _probe),	\
+	__kunit_init_test_suites(CONCATENATE(__UNIQUE_ID(array), _probe), \
 			    ##__suites)
 
 #define kunit_test_init_section_suite(suite)	\
@@ -749,7 +758,7 @@ do {									       \
 		.right_text = #right,					       \
 	};								       \
 									       \
-	if (likely(strcmp(__left, __right) op 0))			       \
+	if (likely((__left) && (__right) && (strcmp(__left, __right) op 0)))   \
 		break;							       \
 									       \
 									       \

include/linux/module.h

@@ -540,6 +540,8 @@ struct module {
 	struct static_call_site *static_call_sites;
 #endif
 #if IS_ENABLED(CONFIG_KUNIT)
+	int num_kunit_init_suites;
+	struct kunit_suite **kunit_init_suites;
 	int num_kunit_suites;
 	struct kunit_suite **kunit_suites;
 #endif

kernel/module/main.c

@@ -2199,6 +2199,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 	mod->kunit_suites = section_objs(info, ".kunit_test_suites",
 					      sizeof(*mod->kunit_suites),
 					      &mod->num_kunit_suites);
+	mod->kunit_init_suites = section_objs(info, ".kunit_init_test_suites",
+					      sizeof(*mod->kunit_init_suites),
+					      &mod->num_kunit_init_suites);
 #endif
 
 	mod->extable = section_objs(info, "__ex_table",

lib/fortify_kunit.c

@@ -15,6 +15,7 @@
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <kunit/device.h>
 #include <kunit/test.h>
 #include <linux/device.h>
 #include <linux/slab.h>
@@ -269,7 +270,7 @@ DEFINE_ALLOC_SIZE_TEST_PAIR(kvmalloc)
 	size_t len;							\
 									\
 	/* Create dummy device for devm_kmalloc()-family tests. */	\
-	dev = root_device_register(dev_name);				\
+	dev = kunit_device_register(test, dev_name);			\
 	KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev),			\
 			       "Cannot register test device\n");	\
 									\
@@ -303,7 +304,7 @@ DEFINE_ALLOC_SIZE_TEST_PAIR(kvmalloc)
 	checker(len, devm_kmemdup(dev, "Ohai", len, gfp),		\
 		devm_kfree(dev, p));					\
 									\
-	device_unregister(dev);						\
+	kunit_device_unregister(test, dev);				\
 } while (0)
 DEFINE_ALLOC_SIZE_TEST_PAIR(devm_kmalloc)
 

lib/kunit/Makefile

@@ -7,7 +7,8 @@ kunit-objs +=				test.o \
 					assert.o \
 					try-catch.o \
 					executor.o \
-					attributes.o
+					attributes.o \
+					device.o
 
 ifeq ($(CONFIG_KUNIT_DEBUGFS),y)
 kunit-objs +=				debugfs.o

lib/kunit/attributes.c

@@ -58,6 +58,16 @@ static const char *attr_enum_to_string(void *attr, const char * const str_list[]
 	return str_list[val];
 }
 
+static const char *attr_bool_to_string(void *attr, bool *to_free)
+{
+	bool val = (bool)attr;
+
+	*to_free = false;
+	if (val)
+		return "true";
+	return "false";
+}
+
 static const char *attr_speed_to_string(void *attr, bool *to_free)
 {
 	return attr_enum_to_string(attr, speed_str_list, to_free);
@@ -166,6 +176,37 @@ static int attr_string_filter(void *attr, const char *input, int *err)
 	return false;
 }
 
+static int attr_bool_filter(void *attr, const char *input, int *err)
+{
+	int i, input_int = -1;
+	long val = (long)attr;
+	const char *input_str = NULL;
+
+	for (i = 0; input[i]; i++) {
+		if (!strchr(op_list, input[i])) {
+			input_str = input + i;
+			break;
+		}
+	}
+
+	if (!input_str) {
+		*err = -EINVAL;
+		pr_err("kunit executor: filter value not found: %s\n", input);
+		return false;
+	}
+
+	if (!strcmp(input_str, "true"))
+		input_int = (int)true;
+	else if (!strcmp(input_str, "false"))
+		input_int = (int)false;
+	else {
+		*err = -EINVAL;
+		pr_err("kunit executor: invalid filter input: %s\n", input);
+		return false;
+	}
+
+	return int_filter(val, input, input_int, err);
+}
 
 /* Get Attribute Methods */
 
@@ -194,6 +235,17 @@ static void *attr_module_get(void *test_or_suite, bool is_test)
 		return (void *) "";
 }
 
+static void *attr_is_init_get(void *test_or_suite, bool is_test)
+{
+	struct kunit_suite *suite = is_test ? NULL : test_or_suite;
+	struct kunit_case *test = is_test ? test_or_suite : NULL;
+
+	if (test)
+		return ((void *) NULL);
+	else
+		return ((void *) suite->is_init);
+}
+
 /* List of all Test Attributes */
 
 static struct kunit_attr kunit_attr_list[] = {
@@ -212,6 +264,14 @@ static struct kunit_attr kunit_attr_list[] = {
 		.filter = attr_string_filter,
 		.attr_default = (void *)"",
 		.print = PRINT_SUITE,
+	},
+	{
+		.name = "is_init",
+		.get_attr = attr_is_init_get,
+		.to_string = attr_bool_to_string,
+		.filter = attr_bool_filter,
+		.attr_default = (void *)false,
+		.print = PRINT_SUITE,
 	}
 };
 

lib/kunit/debugfs.c

@@ -8,12 +8,14 @@
 #include <linux/module.h>
 
 #include <kunit/test.h>
+#include <kunit/test-bug.h>
 
 #include "string-stream.h"
 #include "debugfs.h"
 
 #define KUNIT_DEBUGFS_ROOT             "kunit"
 #define KUNIT_DEBUGFS_RESULTS          "results"
+#define KUNIT_DEBUGFS_RUN              "run"
 
 /*
  * Create a debugfs representation of test suites:
@@ -21,6 +23,8 @@
  * Path						Semantics
  * /sys/kernel/debug/kunit/<testsuite>/results	Show results of last run for
  *						testsuite
+ * /sys/kernel/debug/kunit/<testsuite>/run	Write to this file to trigger
+ *						testsuite to run
  *
  */
 
@@ -60,12 +64,14 @@ static void debugfs_print_result(struct seq_file *seq, struct string_stream *log
 static int debugfs_print_results(struct seq_file *seq, void *v)
 {
 	struct kunit_suite *suite = (struct kunit_suite *)seq->private;
-	enum kunit_status success = kunit_suite_has_succeeded(suite);
+	enum kunit_status success;
 	struct kunit_case *test_case;
 
 	if (!suite)
 		return 0;
 
+	success = kunit_suite_has_succeeded(suite);
+
 	/* Print KTAP header so the debugfs log can be parsed as valid KTAP. */
 	seq_puts(seq, "KTAP version 1\n");
 	seq_puts(seq, "1..1\n");
@@ -99,6 +105,51 @@ static int debugfs_results_open(struct inode *inode, struct file *file)
 	return single_open(file, debugfs_print_results, suite);
 }
 
+/*
+ * Print a usage message to the debugfs "run" file
+ * (/sys/kernel/debug/kunit/<testsuite>/run) if opened.
+ */
+static int debugfs_print_run(struct seq_file *seq, void *v)
+{
+	struct kunit_suite *suite = (struct kunit_suite *)seq->private;
+
+	seq_puts(seq, "Write to this file to trigger the test suite to run.\n");
+	seq_printf(seq, "usage: echo \"any string\" > /sys/kernel/debugfs/kunit/%s/run\n",
+			suite->name);
+	return 0;
+}
+
+/*
+ * The debugfs "run" file (/sys/kernel/debug/kunit/<testsuite>/run)
+ * contains no information. Write to the file to trigger the test suite
+ * to run.
+ */
+static int debugfs_run_open(struct inode *inode, struct file *file)
+{
+	struct kunit_suite *suite;
+
+	suite = (struct kunit_suite *)inode->i_private;
+
+	return single_open(file, debugfs_print_run, suite);
+}
+
+/*
+ * Trigger a test suite to run by writing to the suite's "run" debugfs
+ * file found at: /sys/kernel/debug/kunit/<testsuite>/run
+ *
+ * Note: what is written to this file will not be saved.
+ */
+static ssize_t debugfs_run(struct file *file,
+		const char __user *buf, size_t count, loff_t *ppos)
+{
+	struct inode *f_inode = file->f_inode;
+	struct kunit_suite *suite = (struct kunit_suite *) f_inode->i_private;
+
+	__kunit_test_suites_init(&suite, 1);
+
+	return count;
+}
+
 static const struct file_operations debugfs_results_fops = {
 	.open = debugfs_results_open,
 	.read = seq_read,
@@ -106,17 +157,43 @@ static const struct file_operations debugfs_results_fops = {
 	.release = debugfs_release,
 };
 
+static const struct file_operations debugfs_run_fops = {
+	.open = debugfs_run_open,
+	.read = seq_read,
+	.write = debugfs_run,
+	.llseek = seq_lseek,
+	.release = debugfs_release,
+};
+
 void kunit_debugfs_create_suite(struct kunit_suite *suite)
 {
 	struct kunit_case *test_case;
+	struct string_stream *stream;
 
-	/* Allocate logs before creating debugfs representation. */
-	suite->log = alloc_string_stream(GFP_KERNEL);
-	string_stream_set_append_newlines(suite->log, true);
+	/* If suite log already allocated, do not create new debugfs files. */
+	if (suite->log)
+		return;
+
+	/*
+	 * Allocate logs before creating debugfs representation.
+	 * The suite->log and test_case->log pointer are expected to be NULL
+	 * if there isn't a log, so only set it if the log stream was created
+	 * successfully.
+	 */
+	stream = alloc_string_stream(GFP_KERNEL);
+	if (IS_ERR_OR_NULL(stream))
+		return;
+
+	string_stream_set_append_newlines(stream, true);
+	suite->log = stream;
 
 	kunit_suite_for_each_test_case(suite, test_case) {
-		test_case->log = alloc_string_stream(GFP_KERNEL);
-		string_stream_set_append_newlines(test_case->log, true);
+		stream = alloc_string_stream(GFP_KERNEL);
+		if (IS_ERR_OR_NULL(stream))
+			goto err;
+
+		string_stream_set_append_newlines(stream, true);
+		test_case->log = stream;
 	}
 
 	suite->debugfs = debugfs_create_dir(suite->name, debugfs_rootdir);
@@ -124,6 +201,19 @@ void kunit_debugfs_create_suite(struct kunit_suite *suite)
 	debugfs_create_file(KUNIT_DEBUGFS_RESULTS, S_IFREG | 0444,
 			    suite->debugfs,
 			    suite, &debugfs_results_fops);
+
+	/* Do not create file to re-run test if test runs on init */
+	if (!suite->is_init) {
+		debugfs_create_file(KUNIT_DEBUGFS_RUN, S_IFREG | 0644,
+				    suite->debugfs,
+				    suite, &debugfs_run_fops);
+	}
+	return;
+
+err:
+	string_stream_destroy(suite->log);
+	kunit_suite_for_each_test_case(suite, test_case)
+		string_stream_destroy(test_case->log);
 }
 
 void kunit_debugfs_destroy_suite(struct kunit_suite *suite)

lib/kunit/device-impl.h

@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KUnit internal header for device helpers
+ *
+ * Header for KUnit-internal driver / bus management.
+ *
+ * Copyright (C) 2023, Google LLC.
+ * Author: David Gow <davidgow@google.com>
+ */
+
+#ifndef _KUNIT_DEVICE_IMPL_H
+#define _KUNIT_DEVICE_IMPL_H
+
+// For internal use only -- registers the kunit_bus.
+int kunit_bus_init(void);
+
+#endif //_KUNIT_DEVICE_IMPL_H

lib/kunit/device.c

@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit-managed device implementation
+ *
+ * Implementation of struct kunit_device helpers for fake devices whose
+ * lifecycle is managed by KUnit.
+ *
+ * Copyright (C) 2023, Google LLC.
+ * Author: David Gow <davidgow@google.com>
+ */
+
+#include <linux/device.h>
+
+#include <kunit/test.h>
+#include <kunit/device.h>
+#include <kunit/resource.h>
+
+#include "device-impl.h"
+
+/* Wrappers for use with kunit_add_action() */
+KUNIT_DEFINE_ACTION_WRAPPER(device_unregister_wrapper, device_unregister, struct device *);
+KUNIT_DEFINE_ACTION_WRAPPER(driver_unregister_wrapper, driver_unregister, struct device_driver *);
+
+/* The root device for the KUnit bus, parent of all kunit_devices. */
+static struct device *kunit_bus_device;
+
+/* A device owned by a KUnit test. */
+struct kunit_device {
+	struct device dev;
+	/* The KUnit test which owns this device. */
+	struct kunit *owner;
+	/* If the driver is managed by KUnit and unique to this device. */
+	const struct device_driver *driver;
+};
+
+#define to_kunit_device(d) container_of_const(d, struct kunit_device, dev)
+
+static struct bus_type kunit_bus_type = {
+	.name		= "kunit",
+};
+
+/* Register the 'kunit_bus' used for fake devices. */
+int kunit_bus_init(void)
+{
+	int error;
+
+	kunit_bus_device = root_device_register("kunit");
+	if (!kunit_bus_device)
+		return -ENOMEM;
+
+	error = bus_register(&kunit_bus_type);
+	if (error)
+		bus_unregister(&kunit_bus_type);
+	return error;
+}
+
+/* Release a 'fake' KUnit device. */
+static void kunit_device_release(struct device *d)
+{
+	kfree(to_kunit_device(d));
+}
+
+/*
+ * Create and register a KUnit-managed struct device_driver on the kunit_bus.
+ * Returns an error pointer on failure.
+ */
+struct device_driver *kunit_driver_create(struct kunit *test, const char *name)
+{
+	struct device_driver *driver;
+	int err = -ENOMEM;
+
+	driver = kunit_kzalloc(test, sizeof(*driver), GFP_KERNEL);
+
+	if (!driver)
+		return ERR_PTR(err);
+
+	driver->name = name;
+	driver->bus = &kunit_bus_type;
+	driver->owner = THIS_MODULE;
+
+	err = driver_register(driver);
+	if (err) {
+		kunit_kfree(test, driver);
+		return ERR_PTR(err);
+	}
+
+	kunit_add_action(test, driver_unregister_wrapper, driver);
+	return driver;
+}
+EXPORT_SYMBOL_GPL(kunit_driver_create);
+
+/* Helper which creates a kunit_device, attaches it to the kunit_bus*/
+static struct kunit_device *kunit_device_register_internal(struct kunit *test,
+							   const char *name,
+							   const struct device_driver *drv)
+{
+	struct kunit_device *kunit_dev;
+	int err = -ENOMEM;
+
+	kunit_dev = kzalloc(sizeof(*kunit_dev), GFP_KERNEL);
+	if (!kunit_dev)
+		return ERR_PTR(err);
+
+	kunit_dev->owner = test;
+
+	err = dev_set_name(&kunit_dev->dev, "%s.%s", test->name, name);
+	if (err) {
+		kfree(kunit_dev);
+		return ERR_PTR(err);
+	}
+
+	kunit_dev->dev.release = kunit_device_release;
+	kunit_dev->dev.bus = &kunit_bus_type;
+	kunit_dev->dev.parent = kunit_bus_device;
+
+	err = device_register(&kunit_dev->dev);
+	if (err) {
+		put_device(&kunit_dev->dev);
+		return ERR_PTR(err);
+	}
+
+	kunit_add_action(test, device_unregister_wrapper, &kunit_dev->dev);
+
+	return kunit_dev;
+}
+
+/*
+ * Create and register a new KUnit-managed device, using the user-supplied device_driver.
+ * On failure, returns an error pointer.
+ */
+struct device *kunit_device_register_with_driver(struct kunit *test,
+						 const char *name,
+						 const struct device_driver *drv)
+{
+	struct kunit_device *kunit_dev = kunit_device_register_internal(test, name, drv);
+
+	if (IS_ERR_OR_NULL(kunit_dev))
+		return ERR_CAST(kunit_dev);
+
+	return &kunit_dev->dev;
+}
+EXPORT_SYMBOL_GPL(kunit_device_register_with_driver);
+
+/*
+ * Create and register a new KUnit-managed device, including a matching device_driver.
+ * On failure, returns an error pointer.
+ */
+struct device *kunit_device_register(struct kunit *test, const char *name)
+{
+	struct device_driver *drv;
+	struct kunit_device *dev;
+
+	drv = kunit_driver_create(test, name);
+	if (IS_ERR(drv))
+		return ERR_CAST(drv);
+
+	dev = kunit_device_register_internal(test, name, drv);
+	if (IS_ERR(dev)) {
+		kunit_release_action(test, driver_unregister_wrapper, (void *)drv);
+		return ERR_CAST(dev);
+	}
+
+	/* Request the driver be freed. */
+	dev->driver = drv;
+
+
+	return &dev->dev;
+}
+EXPORT_SYMBOL_GPL(kunit_device_register);
+
+/* Unregisters a KUnit-managed device early (including the driver, if automatically created). */
+void kunit_device_unregister(struct kunit *test, struct device *dev)
+{
+	const struct device_driver *driver = to_kunit_device(dev)->driver;
+
+	kunit_release_action(test, device_unregister_wrapper, dev);
+	if (driver)
+		kunit_release_action(test, driver_unregister_wrapper, (void *)driver);
+}
+EXPORT_SYMBOL_GPL(kunit_device_unregister);
+

lib/kunit/executor.c

@@ -12,6 +12,8 @@
  */
 extern struct kunit_suite * const __kunit_suites_start[];
 extern struct kunit_suite * const __kunit_suites_end[];
+extern struct kunit_suite * const __kunit_init_suites_start[];
+extern struct kunit_suite * const __kunit_init_suites_end[];
 
 static char *action_param;
 
@@ -292,6 +294,37 @@ void kunit_exec_list_tests(struct kunit_suite_set *suite_set, bool include_attr)
 	}
 }
 
+struct kunit_suite_set kunit_merge_suite_sets(struct kunit_suite_set init_suite_set,
+		struct kunit_suite_set suite_set)
+{
+	struct kunit_suite_set total_suite_set = {NULL, NULL};
+	struct kunit_suite **total_suite_start = NULL;
+	size_t init_num_suites, num_suites, suite_size;
+	int i = 0;
+
+	init_num_suites = init_suite_set.end - init_suite_set.start;
+	num_suites = suite_set.end - suite_set.start;
+	suite_size = sizeof(suite_set.start);
+
+	/* Allocate memory for array of all kunit suites */
+	total_suite_start = kmalloc_array(init_num_suites + num_suites, suite_size, GFP_KERNEL);
+	if (!total_suite_start)
+		return total_suite_set;
+
+	/* Append and mark init suites and then append all other kunit suites */
+	memcpy(total_suite_start, init_suite_set.start, init_num_suites * suite_size);
+	for (i = 0; i < init_num_suites; i++)
+		total_suite_start[i]->is_init = true;
+
+	memcpy(total_suite_start + init_num_suites, suite_set.start, num_suites * suite_size);
+
+	/* Set kunit suite set start and end */
+	total_suite_set.start = total_suite_start;
+	total_suite_set.end = total_suite_start + (init_num_suites + num_suites);
+
+	return total_suite_set;
+}
+
 #if IS_BUILTIN(CONFIG_KUNIT)
 
 static char *kunit_shutdown;
@@ -313,21 +346,41 @@ static void kunit_handle_shutdown(void)
 
 int kunit_run_all_tests(void)
 {
-	struct kunit_suite_set suite_set = {
+	struct kunit_suite_set suite_set = {NULL, NULL};
+	struct kunit_suite_set filtered_suite_set = {NULL, NULL};
+	struct kunit_suite_set init_suite_set = {
+		__kunit_init_suites_start, __kunit_init_suites_end,
+	};
+	struct kunit_suite_set normal_suite_set = {
 		__kunit_suites_start, __kunit_suites_end,
 	};
+	size_t init_num_suites = init_suite_set.end - init_suite_set.start;
 	int err = 0;
+
+	if (init_num_suites > 0) {
+		suite_set = kunit_merge_suite_sets(init_suite_set, normal_suite_set);
+		if (!suite_set.start)
+			goto out;
+	} else
+		suite_set = normal_suite_set;
+
 	if (!kunit_enabled()) {
 		pr_info("kunit: disabled\n");
-		goto out;
+		goto free_out;
 	}
 
 	if (filter_glob_param || filter_param) {
-		suite_set = kunit_filter_suites(&suite_set, filter_glob_param,
+		filtered_suite_set = kunit_filter_suites(&suite_set, filter_glob_param,
 				filter_param, filter_action_param, &err);
+
+		/* Free original suite set before using filtered suite set */
+		if (init_num_suites > 0)
+			kfree(suite_set.start);
+		suite_set = filtered_suite_set;
+
 		if (err) {
 			pr_err("kunit executor: error filtering suites: %d\n", err);
-			goto out;
+			goto free_out;
 		}
 	}
 
@@ -340,9 +393,12 @@ int kunit_run_all_tests(void)
 	else
 		pr_err("kunit executor: unknown action '%s'\n", action_param);
 
-	if (filter_glob_param || filter_param) { /* a copy was made of each suite */
+free_out:
+	if (filter_glob_param || filter_param)
 		kunit_free_suite_set(suite_set);
-	}
+	else if (init_num_suites > 0)
+		/* Don't use kunit_free_suite_set because suites aren't individually allocated */
+		kfree(suite_set.start);
 
 out:
 	kunit_handle_shutdown();