platform/wmi: Add kunit test for the string conversion code

The string conversion frunctions provided by the WMI driver core
have no dependencies on the remaining WMI API, making them suitable
for unit tests.

Implement such a unit test using kunit. Those unit tests verify that
converting between WMI strings and UTF8 strings works as expected.
They also verify that edge cases are handled correctly.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://patch.msgid.link/20260116204116.4030-5-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

diff --git a/drivers/platform/wmi/tests/Kconfig b/drivers/platform/wmi/tests/Kconfig
index efcbcb51c251f75039f095bf85d71ccc3235b612..f7f0f3c540f564dbabc620f2296d4df6b31de415 100644 (file)
--- a/drivers/platform/wmi/tests/Kconfig
+++ b/drivers/platform/wmi/tests/Kconfig
@@ -14,3 +14,14 @@ config ACPI_WMI_MARSHALLING_KUNIT_TEST
          to the KUnit documentation in Documentation/dev-tools/kunit/.
 
          If unsure, say N.
+
+config ACPI_WMI_STRING_KUNIT_TEST
+       tristate "KUnit Test for ACPI-WMI string conversion" if !KUNIT_ALL_TESTS
+       depends on KUNIT
+       default KUNIT_ALL_TESTS
+       help
+         This builds unit tests for the ACPI-WMI string conversion code.
+         For more information on KUnit and unit tests in general, please refer
+         to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+         If unsure, say N.

diff --git a/drivers/platform/wmi/tests/Makefile b/drivers/platform/wmi/tests/Makefile
index 252c3125353acc6eb5c3d1d6cd0474be4e5f8e99..62c438e26259e3814af678526861a5a2cee47219 100644 (file)
--- a/drivers/platform/wmi/tests/Makefile
+++ b/drivers/platform/wmi/tests/Makefile
@@ -6,3 +6,6 @@
 
 wmi_marshalling_kunit-y                                := marshalling_kunit.o
 obj-$(CONFIG_ACPI_WMI_MARSHALLING_KUNIT_TEST)  += wmi_marshalling_kunit.o
+
+wmi_string_kunit-y                             := string_kunit.o
+obj-$(CONFIG_ACPI_WMI_STRING_KUNIT_TEST)       += wmi_string_kunit.o

diff --git a/drivers/platform/wmi/tests/string_kunit.c b/drivers/platform/wmi/tests/string_kunit.c
new file mode 100644 (file)
index 0000000..9aa3ffa
--- /dev/null
+++ b/drivers/platform/wmi/tests/string_kunit.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * KUnit test for the ACPI-WMI string conversion code.
+ *
+ * Copyright (C) 2025 Armin Wolf <W_Armin@gmx.de>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/wmi.h>
+
+#include <kunit/resource.h>
+#include <kunit/test.h>
+
+#include <asm/byteorder.h>
+
+struct wmi_string_param {
+       const char *name;
+       const struct wmi_string *wmi_string;
+       /*
+        * Remember that using sizeof() on a struct wmi_string will
+        * always return a size of two bytes due to the flexible
+        * array member!
+        */
+       size_t wmi_string_length;
+       const u8 *utf8_string;
+       size_t utf8_string_length;
+};
+
+#define TEST_WMI_STRING_LENGTH 12
+
+static const struct wmi_string test_wmi_string = {
+       .length = cpu_to_le16(10),
+       .chars = {
+               cpu_to_le16(u'T'),
+               cpu_to_le16(u'E'),
+               cpu_to_le16(u'S'),
+               cpu_to_le16(u'T'),
+               cpu_to_le16(u'\0'),
+       },
+};
+
+static const u8 test_utf8_string[] = "TEST";
+
+#define SPECIAL_WMI_STRING_LENGTH 14
+
+static const struct wmi_string special_wmi_string = {
+       .length = cpu_to_le16(12),
+       .chars = {
+               cpu_to_le16(u'Ä'),
+               cpu_to_le16(u'Ö'),
+               cpu_to_le16(u'Ü'),
+               cpu_to_le16(u'ß'),
+               cpu_to_le16(u'€'),
+               cpu_to_le16(u'\0'),
+       },
+};
+
+static const u8 special_utf8_string[] = "ÄÖÜ߀";
+
+#define MULTI_POINT_WMI_STRING_LENGTH 12
+
+static const struct wmi_string multi_point_wmi_string = {
+       .length = cpu_to_le16(10),
+       .chars = {
+               cpu_to_le16(u'K'),
+               /* 🐧 */
+               cpu_to_le16(0xD83D),
+               cpu_to_le16(0xDC27),
+               cpu_to_le16(u'!'),
+               cpu_to_le16(u'\0'),
+       },
+};
+
+static const u8 multi_point_utf8_string[] = "K🐧!";
+
+#define PADDED_TEST_WMI_STRING_LENGTH 14
+
+static const struct wmi_string padded_test_wmi_string = {
+       .length = cpu_to_le16(12),
+       .chars = {
+               cpu_to_le16(u'T'),
+               cpu_to_le16(u'E'),
+               cpu_to_le16(u'S'),
+               cpu_to_le16(u'T'),
+               cpu_to_le16(u'\0'),
+               cpu_to_le16(u'\0'),
+       },
+};
+
+static const u8 padded_test_utf8_string[] = "TEST\0";
+
+#define OVERSIZED_TEST_WMI_STRING_LENGTH 14
+
+static const struct wmi_string oversized_test_wmi_string = {
+       .length = cpu_to_le16(8),
+       .chars = {
+               cpu_to_le16(u'T'),
+               cpu_to_le16(u'E'),
+               cpu_to_le16(u'S'),
+               cpu_to_le16(u'T'),
+               cpu_to_le16(u'!'),
+               cpu_to_le16(u'\0'),
+       },
+};
+
+static const u8 oversized_test_utf8_string[] = "TEST!";
+
+#define INVALID_TEST_WMI_STRING_LENGTH 14
+
+static const struct wmi_string invalid_test_wmi_string = {
+       .length = cpu_to_le16(12),
+       .chars = {
+               cpu_to_le16(u'T'),
+               /* 🐧, with low surrogate missing */
+               cpu_to_le16(0xD83D),
+               cpu_to_le16(u'E'),
+               cpu_to_le16(u'S'),
+               cpu_to_le16(u'T'),
+               cpu_to_le16(u'\0'),
+       },
+};
+
+/* We have to split the string here to end the hex escape sequence */
+static const u8 invalid_test_utf8_string[] = "T" "\xF0\x9F" "EST";
+
+static const struct wmi_string_param wmi_string_params_array[] = {
+       {
+               .name = "ascii_string",
+               .wmi_string = &test_wmi_string,
+               .wmi_string_length = TEST_WMI_STRING_LENGTH,
+               .utf8_string = test_utf8_string,
+               .utf8_string_length = sizeof(test_utf8_string),
+       },
+       {
+               .name = "special_string",
+               .wmi_string = &special_wmi_string,
+               .wmi_string_length = SPECIAL_WMI_STRING_LENGTH,
+               .utf8_string = special_utf8_string,
+               .utf8_string_length = sizeof(special_utf8_string),
+       },
+       {
+               .name = "multi_point_string",
+               .wmi_string = &multi_point_wmi_string,
+               .wmi_string_length = MULTI_POINT_WMI_STRING_LENGTH,
+               .utf8_string = multi_point_utf8_string,
+               .utf8_string_length = sizeof(multi_point_utf8_string),
+       },
+};
+
+static void wmi_string_param_get_desc(const struct wmi_string_param *param, char *desc)
+{
+       strscpy(desc, param->name, KUNIT_PARAM_DESC_SIZE);
+}
+
+KUNIT_ARRAY_PARAM(wmi_string, wmi_string_params_array, wmi_string_param_get_desc);
+
+static void wmi_string_to_utf8s_test(struct kunit *test)
+{
+       const struct wmi_string_param *param = test->param_value;
+       ssize_t ret;
+       u8 *result;
+
+       result = kunit_kzalloc(test, param->utf8_string_length, GFP_KERNEL);
+       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, result);
+
+       ret = wmi_string_to_utf8s(param->wmi_string, result, param->utf8_string_length);
+
+       KUNIT_EXPECT_EQ(test, ret, param->utf8_string_length - 1);
+       KUNIT_EXPECT_MEMEQ(test, result, param->utf8_string, param->utf8_string_length);
+}
+
+static void wmi_string_from_utf8s_test(struct kunit *test)
+{
+       const struct wmi_string_param *param = test->param_value;
+       struct wmi_string *result;
+       size_t max_chars;
+       ssize_t ret;
+
+       max_chars = (param->wmi_string_length - sizeof(*result)) / 2;
+       result = kunit_kzalloc(test, param->wmi_string_length, GFP_KERNEL);
+       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, result);
+
+       ret = wmi_string_from_utf8s(result, max_chars, param->utf8_string,
+                                   param->utf8_string_length);
+
+       KUNIT_EXPECT_EQ(test, ret, max_chars - 1);
+       KUNIT_EXPECT_MEMEQ(test, result, param->wmi_string, param->wmi_string_length);
+}
+
+static void wmi_string_to_utf8s_padded_test(struct kunit *test)
+{
+       u8 result[sizeof(padded_test_utf8_string)];
+       ssize_t ret;
+
+       ret = wmi_string_to_utf8s(&padded_test_wmi_string, result, sizeof(result));
+
+       KUNIT_EXPECT_EQ(test, ret, sizeof(test_utf8_string) - 1);
+       KUNIT_EXPECT_MEMEQ(test, result, test_utf8_string, sizeof(test_utf8_string));
+}
+
+static void wmi_string_from_utf8s_padded_test(struct kunit *test)
+{
+       struct wmi_string *result;
+       size_t max_chars;
+       ssize_t ret;
+
+       max_chars = (PADDED_TEST_WMI_STRING_LENGTH - sizeof(*result)) / 2;
+       result = kunit_kzalloc(test, PADDED_TEST_WMI_STRING_LENGTH, GFP_KERNEL);
+       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, result);
+
+       ret = wmi_string_from_utf8s(result, max_chars, padded_test_utf8_string,
+                                   sizeof(padded_test_utf8_string));
+
+       KUNIT_EXPECT_EQ(test, ret, sizeof(test_utf8_string) - 1);
+       KUNIT_EXPECT_MEMEQ(test, result, &test_wmi_string, sizeof(test_wmi_string));
+}
+
+static void wmi_string_to_utf8s_oversized_test(struct kunit *test)
+{
+       u8 result[sizeof(oversized_test_utf8_string)];
+       ssize_t ret;
+
+       ret = wmi_string_to_utf8s(&oversized_test_wmi_string, result, sizeof(result));
+
+       KUNIT_EXPECT_EQ(test, ret, sizeof(test_utf8_string) - 1);
+       KUNIT_EXPECT_MEMEQ(test, result, test_utf8_string, sizeof(test_utf8_string));
+}
+
+static void wmi_string_to_utf8s_invalid_test(struct kunit *test)
+{
+       u8 result[sizeof(invalid_test_utf8_string)];
+       ssize_t ret;
+
+       ret = wmi_string_to_utf8s(&invalid_test_wmi_string, result, sizeof(result));
+
+       KUNIT_EXPECT_EQ(test, ret, sizeof(test_utf8_string) - 1);
+       KUNIT_EXPECT_MEMEQ(test, result, test_utf8_string, sizeof(test_utf8_string));
+}
+
+static void wmi_string_from_utf8s_invalid_test(struct kunit *test)
+{
+       struct wmi_string *result;
+       size_t max_chars;
+       ssize_t ret;
+
+       max_chars = (INVALID_TEST_WMI_STRING_LENGTH - sizeof(*result)) / 2;
+       result = kunit_kzalloc(test, INVALID_TEST_WMI_STRING_LENGTH, GFP_KERNEL);
+       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, result);
+
+       ret = wmi_string_from_utf8s(result, max_chars, invalid_test_utf8_string,
+                                   sizeof(invalid_test_utf8_string));
+
+       KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+}
+
+static struct kunit_case wmi_string_test_cases[] = {
+       KUNIT_CASE_PARAM(wmi_string_to_utf8s_test, wmi_string_gen_params),
+       KUNIT_CASE_PARAM(wmi_string_from_utf8s_test, wmi_string_gen_params),
+       KUNIT_CASE(wmi_string_to_utf8s_padded_test),
+       KUNIT_CASE(wmi_string_from_utf8s_padded_test),
+       KUNIT_CASE(wmi_string_to_utf8s_oversized_test),
+       KUNIT_CASE(wmi_string_to_utf8s_invalid_test),
+       KUNIT_CASE(wmi_string_from_utf8s_invalid_test),
+       {}
+};
+
+static struct kunit_suite wmi_string_test_suite = {
+       .name = "wmi_string",
+       .test_cases = wmi_string_test_cases,
+};
+
+kunit_test_suite(wmi_string_test_suite);
+
+MODULE_AUTHOR("Armin Wolf <W_Armin@gmx.de>");
+MODULE_DESCRIPTION("KUnit test for the ACPI-WMI string conversion code");
+MODULE_LICENSE("GPL");