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, 47 insertions, 0 deletions

diff --git a/include/sound/rt5659.h b/include/sound/rt5659.h
new file mode 100644
index 000000000..d495311df
--- /dev/null
+++ b/include/sound/rt5659.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * linux/sound/rt5659.h -- Platform data for RT5659
+ *
+ * Copyright 2013 Realtek Microelectronics
+ */
+
+#ifndef __LINUX_SND_RT5659_H
+#define __LINUX_SND_RT5659_H
+
+enum rt5659_dmic1_data_pin {
+	RT5659_DMIC1_NULL,
+	RT5659_DMIC1_DATA_IN2N,
+	RT5659_DMIC1_DATA_GPIO5,
+	RT5659_DMIC1_DATA_GPIO9,
+	RT5659_DMIC1_DATA_GPIO11,
+};
+
+enum rt5659_dmic2_data_pin {
+	RT5659_DMIC2_NULL,
+	RT5659_DMIC2_DATA_IN2P,
+	RT5659_DMIC2_DATA_GPIO6,
+	RT5659_DMIC2_DATA_GPIO10,
+	RT5659_DMIC2_DATA_GPIO12,
+};
+
+enum rt5659_jd_src {
+	RT5659_JD_NULL,
+	RT5659_JD3,
+	RT5659_JD_HDA_HEADER,
+};
+
+struct rt5659_platform_data {
+	bool in1_diff;
+	bool in3_diff;
+	bool in4_diff;
+
+	int ldo1_en; /* GPIO for LDO1_EN */
+	int reset; /* GPIO for RESET */
+
+	enum rt5659_dmic1_data_pin dmic1_data_pin;
+	enum rt5659_dmic2_data_pin dmic2_data_pin;
+	enum rt5659_jd_src jd_src;
+};
+
+#endif
+