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, 61 insertions, 0 deletions

diff --git a/include/sound/max98095.h b/include/sound/max98095.h
new file mode 100644
index 000000000..731c88551
--- /dev/null
+++ b/include/sound/max98095.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Platform data for MAX98095
+ *
+ * Copyright 2011 Maxim Integrated Products
+ */
+
+#ifndef __SOUND_MAX98095_PDATA_H__
+#define __SOUND_MAX98095_PDATA_H__
+
+/* Equalizer filter response configuration */
+struct max98095_eq_cfg {
+	const char *name;
+	unsigned int rate;
+	u16 band1[5];
+	u16 band2[5];
+	u16 band3[5];
+	u16 band4[5];
+	u16 band5[5];
+};
+
+/* Biquad filter response configuration */
+struct max98095_biquad_cfg {
+	const char *name;
+	unsigned int rate;
+	u16 band1[5];
+	u16 band2[5];
+};
+
+/* codec platform data */
+struct max98095_pdata {
+
+	/* Equalizers for DAI1 and DAI2 */
+	struct max98095_eq_cfg *eq_cfg;
+	unsigned int eq_cfgcnt;
+
+	/* Biquad filter for DAI1 and DAI2 */
+	struct max98095_biquad_cfg *bq_cfg;
+	unsigned int bq_cfgcnt;
+
+	/* Analog/digital microphone configuration:
+	 * 0 = analog microphone input (normal setting)
+	 * 1 = digital microphone input
+	 */
+	unsigned int digmic_left_mode:1;
+	unsigned int digmic_right_mode:1;
+
+	/* Pin5 is the mechanical method of sensing jack insertion
+	 * but it is something that might not be supported.
+	 * 0 = PIN5 not supported
+	 * 1 = PIN5 supported
+	 */
+	unsigned int jack_detect_pin5en:1;
+
+	/* Slew amount for jack detection. Calculated as 4 * (delay + 1).
+	 * Default delay is 24 to get a time of 100ms.
+	 */
+	unsigned int jack_detect_delay;
+};
+
+#endif