Commit dc7c5163 authored by Takashi Sakamoto's avatar Takashi Sakamoto
Browse files

firewire: add KUnit test to check layout of UAPI structures 

In future commits, some new structure will be added to express new type
of event. They are exposed to user space as the part of UAPI. It is likely
to get trouble in ioctl compatibility layer for 32 bit binaries in 64 bit
host machine since the layout of structure could differ depending on
System V ABI for these architectures. Actually the subsystem already got
such trouble at v2.6.27. It is preferable to decide the layout of
structure carefully so that the layer is free from such trouble.

This commit utilizes KUnit framework to check the layout of structure for
the purpose. A test is added for the existent issue.

Cc: kunit-dev@googlegroups.com
Link: https://lore.kernel.org/r/20230529113406.986289-2-o-takashi@sakamocchi.jp


Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
parent 44c026a7

drivers/firewire/.kunitconfig

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+4 −0
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CONFIG_KUNIT=y

CONFIG_PCI=y

CONFIG_FIREWIRE=y

CONFIG_FIREWIRE_KUNIT_UAPI_TEST=y

drivers/firewire/Kconfig

+16 −0
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@@ -18,6 +18,22 @@ config FIREWIRE 
	  To compile this driver as a module, say M here: the module will be

	  called firewire-core.



config FIREWIRE_KUNIT_UAPI_TEST

	tristate "KUnit tests for layout of structure in UAPI" if !KUNIT_ALL_TESTS

	depends on FIREWIRE && KUNIT

	default KUNIT_ALL_TESTS

	help

	  This builds the KUnit tests whether structures exposed to user

	  space have expected layout.



	  KUnit tests run during boot and output the results to the debug

	  log in TAP format (https://testanything.org/). Only useful for

	  kernel devs running KUnit test harness and are not for inclusion

	  into a production build.



	  For more information on KUnit and unit tests in general, refer

	  to the KUnit documentation in Documentation/dev-tools/kunit/.



config FIREWIRE_OHCI

	tristate "OHCI-1394 controllers"

	depends on PCI && FIREWIRE && MMU

drivers/firewire/Makefile

+3 −0
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@@ -15,3 +15,6 @@ obj-$(CONFIG_FIREWIRE_SBP2) += firewire-sbp2.o 
obj-$(CONFIG_FIREWIRE_NET)  += firewire-net.o

obj-$(CONFIG_FIREWIRE_NOSY) += nosy.o

obj-$(CONFIG_PROVIDE_OHCI1394_DMA_INIT) += init_ohci1394_dma.o



firewire-uapi-test-objs += uapi-test.o

obj-$(CONFIG_FIREWIRE_KUNIT_UAPI_TEST) += firewire-uapi-test.o

drivers/firewire/uapi-test.c

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// SPDX-License-Identifier: GPL-2.0-only

//

// uapi_test.c - An application of Kunit to check layout of structures exposed to user space for

//		 FireWire subsystem.

//

// Copyright (c) 2023 Takashi Sakamoto



#include <kunit/test.h>

#include <linux/firewire-cdev.h>



// Known issue added at v2.6.27 kernel.

static void structure_layout_event_response(struct kunit *test)

{

#if defined(CONFIG_X86_32)

	// 4 bytes alignment for aggregate type including 8 bytes storage types.

	KUNIT_EXPECT_EQ(test, 20, sizeof(struct fw_cdev_event_response));

#else

	// 8 bytes alignment for aggregate type including 8 bytes storage types.

	KUNIT_EXPECT_EQ(test, 24, sizeof(struct fw_cdev_event_response));

#endif



	KUNIT_EXPECT_EQ(test, 0, offsetof(struct fw_cdev_event_response, closure));

	KUNIT_EXPECT_EQ(test, 8, offsetof(struct fw_cdev_event_response, type));

	KUNIT_EXPECT_EQ(test, 12, offsetof(struct fw_cdev_event_response, rcode));

	KUNIT_EXPECT_EQ(test, 16, offsetof(struct fw_cdev_event_response, length));

	KUNIT_EXPECT_EQ(test, 20, offsetof(struct fw_cdev_event_response, data));

}



static struct kunit_case structure_layout_test_cases[] = {

	KUNIT_CASE(structure_layout_event_response),

	{}

};



static struct kunit_suite structure_layout_test_suite = {

	.name = "firewire-uapi-structure-layout",

	.test_cases = structure_layout_test_cases,

};

kunit_test_suite(structure_layout_test_suite);