kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 422 insertions, 0 deletions

diff --git a/drivers/phy/phy-common-props-test.c b/drivers/phy/phy-common-props-test.c
new file mode 100644
index 000000000..e937ec8a4
--- /dev/null
+++ b/drivers/phy/phy-common-props-test.c
@@ -0,0 +1,422 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * phy-common-props-test.c  --  Unit tests for PHY common properties API
+ *
+ * Copyright 2025-2026 NXP
+ */
+#include <kunit/test.h>
+#include <linux/property.h>
+#include <linux/phy/phy-common-props.h>
+#include <dt-bindings/phy/phy.h>
+
+/* Test: rx-polarity property is missing */
+static void phy_test_rx_polarity_is_missing(struct kunit *test)
+{
+	static const struct property_entry entries[] = {
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_rx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_NORMAL);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: rx-polarity has more values than rx-polarity-names */
+static void phy_test_rx_polarity_more_values_than_names(struct kunit *test)
+{
+	static const u32 rx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT, PHY_POL_NORMAL };
+	static const char * const rx_pol_names[] = { "sgmii", "2500base-x" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("rx-polarity", rx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("rx-polarity-names", rx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_rx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: rx-polarity has 1 value and rx-polarity-names does not exist */
+static void phy_test_rx_polarity_single_value_no_names(struct kunit *test)
+{
+	static const u32 rx_pol[] = { PHY_POL_INVERT };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("rx-polarity", rx_pol),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_rx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_INVERT);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: rx-polarity-names has more values than rx-polarity */
+static void phy_test_rx_polarity_more_names_than_values(struct kunit *test)
+{
+	static const u32 rx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT };
+	static const char * const rx_pol_names[] = { "sgmii", "2500base-x", "1000base-x" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("rx-polarity", rx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("rx-polarity-names", rx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_rx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: rx-polarity and rx-polarity-names have same length, find the name */
+static void phy_test_rx_polarity_find_by_name(struct kunit *test)
+{
+	static const u32 rx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT, PHY_POL_AUTO };
+	static const char * const rx_pol_names[] = { "sgmii", "2500base-x", "usb-ss" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("rx-polarity", rx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("rx-polarity-names", rx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_rx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_NORMAL);
+
+	ret = phy_get_manual_rx_polarity(node, "2500base-x", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_INVERT);
+
+	ret = phy_get_rx_polarity(node, "usb-ss", BIT(PHY_POL_AUTO),
+				  PHY_POL_AUTO, &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_AUTO);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: same length, name not found, no "default" - error */
+static void phy_test_rx_polarity_name_not_found_no_default(struct kunit *test)
+{
+	static const u32 rx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT };
+	static const char * const rx_pol_names[] = { "2500base-x", "1000base-x" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("rx-polarity", rx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("rx-polarity-names", rx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_rx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: same length, name not found, but "default" exists */
+static void phy_test_rx_polarity_name_not_found_with_default(struct kunit *test)
+{
+	static const u32 rx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT };
+	static const char * const rx_pol_names[] = { "2500base-x", "default" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("rx-polarity", rx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("rx-polarity-names", rx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_rx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_INVERT);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: polarity found but value is unsupported */
+static void phy_test_rx_polarity_unsupported_value(struct kunit *test)
+{
+	static const u32 rx_pol[] = { PHY_POL_AUTO };
+	static const char * const rx_pol_names[] = { "sgmii" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("rx-polarity", rx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("rx-polarity-names", rx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_rx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, -EOPNOTSUPP);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: tx-polarity property is missing */
+static void phy_test_tx_polarity_is_missing(struct kunit *test)
+{
+	static const struct property_entry entries[] = {
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_tx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_NORMAL);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: tx-polarity has more values than tx-polarity-names */
+static void phy_test_tx_polarity_more_values_than_names(struct kunit *test)
+{
+	static const u32 tx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT, PHY_POL_NORMAL };
+	static const char * const tx_pol_names[] = { "sgmii", "2500base-x" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("tx-polarity", tx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("tx-polarity-names", tx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_tx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: tx-polarity has 1 value and tx-polarity-names does not exist */
+static void phy_test_tx_polarity_single_value_no_names(struct kunit *test)
+{
+	static const u32 tx_pol[] = { PHY_POL_INVERT };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("tx-polarity", tx_pol),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_tx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_INVERT);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: tx-polarity-names has more values than tx-polarity */
+static void phy_test_tx_polarity_more_names_than_values(struct kunit *test)
+{
+	static const u32 tx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT };
+	static const char * const tx_pol_names[] = { "sgmii", "2500base-x", "1000base-x" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("tx-polarity", tx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("tx-polarity-names", tx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_tx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: tx-polarity and tx-polarity-names have same length, find the name */
+static void phy_test_tx_polarity_find_by_name(struct kunit *test)
+{
+	static const u32 tx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT, PHY_POL_NORMAL };
+	static const char * const tx_pol_names[] = { "sgmii", "2500base-x", "1000base-x" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("tx-polarity", tx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("tx-polarity-names", tx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_tx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_NORMAL);
+
+	ret = phy_get_manual_tx_polarity(node, "2500base-x", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_INVERT);
+
+	ret = phy_get_manual_tx_polarity(node, "1000base-x", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_NORMAL);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: same length, name not found, no "default" - error */
+static void phy_test_tx_polarity_name_not_found_no_default(struct kunit *test)
+{
+	static const u32 tx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT };
+	static const char * const tx_pol_names[] = { "2500base-x", "1000base-x" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("tx-polarity", tx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("tx-polarity-names", tx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_tx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, -EINVAL);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: same length, name not found, but "default" exists */
+static void phy_test_tx_polarity_name_not_found_with_default(struct kunit *test)
+{
+	static const u32 tx_pol[] = { PHY_POL_NORMAL, PHY_POL_INVERT };
+	static const char * const tx_pol_names[] = { "2500base-x", "default" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("tx-polarity", tx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("tx-polarity-names", tx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_tx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, val, PHY_POL_INVERT);
+
+	fwnode_remove_software_node(node);
+}
+
+/* Test: polarity found but value is unsupported (AUTO for TX) */
+static void phy_test_tx_polarity_unsupported_value(struct kunit *test)
+{
+	static const u32 tx_pol[] = { PHY_POL_AUTO };
+	static const char * const tx_pol_names[] = { "sgmii" };
+	static const struct property_entry entries[] = {
+		PROPERTY_ENTRY_U32_ARRAY("tx-polarity", tx_pol),
+		PROPERTY_ENTRY_STRING_ARRAY("tx-polarity-names", tx_pol_names),
+		{}
+	};
+	struct fwnode_handle *node;
+	unsigned int val;
+	int ret;
+
+	node = fwnode_create_software_node(entries, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
+
+	ret = phy_get_manual_tx_polarity(node, "sgmii", &val);
+	KUNIT_EXPECT_EQ(test, ret, -EOPNOTSUPP);
+
+	fwnode_remove_software_node(node);
+}
+
+static struct kunit_case phy_common_props_test_cases[] = {
+	KUNIT_CASE(phy_test_rx_polarity_is_missing),
+	KUNIT_CASE(phy_test_rx_polarity_more_values_than_names),
+	KUNIT_CASE(phy_test_rx_polarity_single_value_no_names),
+	KUNIT_CASE(phy_test_rx_polarity_more_names_than_values),
+	KUNIT_CASE(phy_test_rx_polarity_find_by_name),
+	KUNIT_CASE(phy_test_rx_polarity_name_not_found_no_default),
+	KUNIT_CASE(phy_test_rx_polarity_name_not_found_with_default),
+	KUNIT_CASE(phy_test_rx_polarity_unsupported_value),
+	KUNIT_CASE(phy_test_tx_polarity_is_missing),
+	KUNIT_CASE(phy_test_tx_polarity_more_values_than_names),
+	KUNIT_CASE(phy_test_tx_polarity_single_value_no_names),
+	KUNIT_CASE(phy_test_tx_polarity_more_names_than_values),
+	KUNIT_CASE(phy_test_tx_polarity_find_by_name),
+	KUNIT_CASE(phy_test_tx_polarity_name_not_found_no_default),
+	KUNIT_CASE(phy_test_tx_polarity_name_not_found_with_default),
+	KUNIT_CASE(phy_test_tx_polarity_unsupported_value),
+	{}
+};
+
+static struct kunit_suite phy_common_props_test_suite = {
+	.name = "phy-common-props",
+	.test_cases = phy_common_props_test_cases,
+};
+
+kunit_test_suite(phy_common_props_test_suite);
+
+MODULE_DESCRIPTION("Test module for PHY common properties API");
+MODULE_AUTHOR("Vladimir Oltean <vladimir.oltean@nxp.com>");
+MODULE_LICENSE("GPL");