lib: packing: add KUnit tests adapted from selftests

Add 24 simple KUnit tests for the lib/packing.c pack() and unpack() APIs.

The first 16 tests exercise all combinations of quirks with a simple magic
number value on a 16-byte buffer. The remaining 8 tests cover
non-multiple-of-4 buffer sizes.

These tests were originally written by Vladimir as simple selftest
functions. I adapted them to KUnit, refactoring them into a table driven
approach. This will aid in adding additional tests in the future.

Co-developed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20241002-packing-kunit-tests-and-split-pack-unpack-v2-6-8373e551eae3@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

MAINTAINERS

@@ -17471,6 +17471,7 @@ S:	Supported
 F:	Documentation/core-api/packing.rst
 F:	include/linux/packing.h
 F:	lib/packing.c
+F:	lib/packing_test.c
 
 PADATA PARALLEL EXECUTION MECHANISM
 M:	Steffen Klassert <steffen.klassert@secunet.com>

lib/Kconfig

@@ -40,6 +40,18 @@ config PACKING
 
 	  When in doubt, say N.
 
+config PACKING_KUNIT_TEST
+	tristate "KUnit tests for packing library" if !KUNIT_ALL_TESTS
+	depends on PACKING && KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This builds KUnit tests for the packing library.
+
+	  For more information on KUnit and unit tests in general,
+	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  When in doubt, say N.
+
 config BITREVERSE
 	tristate
 

lib/Makefile

@@ -154,6 +154,7 @@ obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o
 obj-$(CONFIG_BITREVERSE) += bitrev.o
 obj-$(CONFIG_LINEAR_RANGES) += linear_ranges.o
 obj-$(CONFIG_PACKING)	+= packing.o
+obj-$(CONFIG_PACKING_KUNIT_TEST) += packing_test.o
 obj-$(CONFIG_CRC_CCITT)	+= crc-ccitt.o
 obj-$(CONFIG_CRC16)	+= crc16.o
 obj-$(CONFIG_CRC_T10DIF)+= crc-t10dif.o

lib/packing_test.c

@@ -0,0 +1,258 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024, Vladimir Oltean <olteanv@gmail.com>
+ * Copyright (c) 2024, Intel Corporation.
+ */
+#include <kunit/test.h>
+#include <linux/packing.h>
+
+struct packing_test_case {
+	const char *desc;
+	const u8 *pbuf;
+	size_t pbuf_size;
+	u64 uval;
+	size_t start_bit;
+	size_t end_bit;
+	u8 quirks;
+};
+
+#define NO_QUIRKS	0
+
+/**
+ * PBUF - Initialize .pbuf and .pbuf_size
+ * @array: elements of constant physical buffer
+ *
+ * Initializes the .pbuf and .pbuf_size fields of a struct packing_test_case
+ * with a constant array of the specified elements.
+ */
+#define PBUF(array...)					\
+	.pbuf = (const u8[]){ array },			\
+	.pbuf_size = sizeof((const u8 []){ array })
+
+static const struct packing_test_case cases[] = {
+	/* These tests pack and unpack a magic 64-bit value
+	 * (0xcafedeadbeefcafe) at a fixed logical offset (32) within an
+	 * otherwise zero array of 128 bits (16 bytes). They test all possible
+	 * bit layouts of the 128 bit buffer.
+	 */
+	{
+		.desc = "no quirks, 16 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xca, 0xfe, 0xde, 0xad,
+		     0xbe, 0xef, 0xca, 0xfe, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = NO_QUIRKS,
+	},
+	{
+		.desc = "lsw32 first, 16 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xbe, 0xef, 0xca, 0xfe,
+		     0xca, 0xfe, 0xde, 0xad, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_LSW32_IS_FIRST,
+	},
+	{
+		.desc = "little endian words, 16 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xad, 0xde, 0xfe, 0xca,
+		     0xfe, 0xca, 0xef, 0xbe, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_LITTLE_ENDIAN,
+	},
+	{
+		.desc = "lsw32 first + little endian words, 16 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe,
+		     0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN,
+	},
+	{
+		.desc = "msb right, 16 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0x53, 0x7f, 0x7b, 0xb5,
+		     0x7d, 0xf7, 0x53, 0x7f, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_MSB_ON_THE_RIGHT,
+	},
+	{
+		.desc = "msb right + lsw32 first, 16 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0x7d, 0xf7, 0x53, 0x7f,
+		     0x53, 0x7f, 0x7b, 0xb5, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LSW32_IS_FIRST,
+	},
+	{
+		.desc = "msb right + little endian words, 16 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xb5, 0x7b, 0x7f, 0x53,
+		     0x7f, 0x53, 0xf7, 0x7d, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LITTLE_ENDIAN,
+	},
+	{
+		.desc = "msb right + lsw32 first + little endian words, 16 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0x7f, 0x53, 0xf7, 0x7d,
+		     0xb5, 0x7b, 0x7f, 0x53, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_MSB_ON_THE_RIGHT | QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN,
+	},
+	/* These tests pack and unpack a magic 64-bit value
+	 * (0xcafedeadbeefcafe) at a fixed logical offset (32) within an
+	 * otherwise zero array of varying size from 18 bytes to 24 bytes.
+	 */
+	{
+		.desc = "no quirks, 18 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xca, 0xfe,
+		     0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe, 0x00, 0x00,
+		     0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = NO_QUIRKS,
+	},
+	{
+		.desc = "no quirks, 19 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xca,
+		     0xfe, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe, 0x00,
+		     0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = NO_QUIRKS,
+	},
+	{
+		.desc = "no quirks, 20 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		     0xca, 0xfe, 0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe,
+		     0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = NO_QUIRKS,
+	},
+	{
+		.desc = "no quirks, 22 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00, 0xca, 0xfe, 0xde, 0xad, 0xbe, 0xef,
+		     0xca, 0xfe, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = NO_QUIRKS,
+	},
+	{
+		.desc = "no quirks, 24 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00, 0x00, 0x00, 0xca, 0xfe, 0xde, 0xad,
+		     0xbe, 0xef, 0xca, 0xfe, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = NO_QUIRKS,
+	},
+	{
+		.desc = "lsw32 first + little endian words, 18 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe,
+		     0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN,
+	},
+	{
+		.desc = "lsw32 first + little endian words, 19 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe,
+		     0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN,
+	},
+	{
+		.desc = "lsw32 first + little endian words, 20 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe,
+		     0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN,
+	},
+	{
+		.desc = "lsw32 first + little endian words, 22 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe,
+		     0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN,
+	},
+	{
+		.desc = "lsw32 first + little endian words, 24 bytes",
+		PBUF(0x00, 0x00, 0x00, 0x00, 0xfe, 0xca, 0xef, 0xbe,
+		     0xad, 0xde, 0xfe, 0xca, 0x00, 0x00, 0x00, 0x00,
+		     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00),
+		.uval = 0xcafedeadbeefcafe,
+		.start_bit = 95,
+		.end_bit = 32,
+		.quirks = QUIRK_LSW32_IS_FIRST | QUIRK_LITTLE_ENDIAN,
+	},
+};
+
+KUNIT_ARRAY_PARAM_DESC(packing, cases, desc);
+
+static void packing_test_pack(struct kunit *test)
+{
+	const struct packing_test_case *params = test->param_value;
+	u8 *pbuf;
+	int err;
+
+	pbuf = kunit_kzalloc(test, params->pbuf_size, GFP_KERNEL);
+
+	err = pack(pbuf, params->uval, params->start_bit, params->end_bit,
+		   params->pbuf_size, params->quirks);
+
+	KUNIT_EXPECT_EQ_MSG(test, err, 0, "pack() returned %pe\n", ERR_PTR(err));
+	KUNIT_EXPECT_MEMEQ(test, pbuf, params->pbuf, params->pbuf_size);
+}
+
+static void packing_test_unpack(struct kunit *test)
+{
+	const struct packing_test_case *params = test->param_value;
+	u64 uval;
+	int err;
+
+	err = unpack(params->pbuf, &uval, params->start_bit, params->end_bit,
+		     params->pbuf_size, params->quirks);
+	KUNIT_EXPECT_EQ_MSG(test, err, 0, "unpack() returned %pe\n", ERR_PTR(err));
+	KUNIT_EXPECT_EQ(test, uval, params->uval);
+}
+
+static struct kunit_case packing_test_cases[] = {
+	KUNIT_CASE_PARAM(packing_test_pack, packing_gen_params),
+	KUNIT_CASE_PARAM(packing_test_unpack, packing_gen_params),
+	{},
+};
+
+static struct kunit_suite packing_test_suite = {
+	.name = "packing",
+	.test_cases = packing_test_cases,
+};
+
+kunit_test_suite(packing_test_suite);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("KUnit tests for packing library");