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/sof/dai-imx.h b/include/sound/sof/dai-imx.h
new file mode 100644
index 000000000..6bc987bd4
--- /dev/null
+++ b/include/sound/sof/dai-imx.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */
+/*
+ * Copyright 2019 NXP
+ *
+ * Author: Daniel Baluta <daniel.baluta@nxp.com>
+ */
+
+#ifndef __INCLUDE_SOUND_SOF_DAI_IMX_H__
+#define __INCLUDE_SOUND_SOF_DAI_IMX_H__
+
+#include <sound/sof/header.h>
+
+/* ESAI Configuration Request - SOF_IPC_DAI_ESAI_CONFIG */
+struct sof_ipc_dai_esai_params {
+	struct sof_ipc_hdr hdr;
+
+	/* MCLK */
+	uint16_t reserved1;
+	uint16_t mclk_id;
+	uint32_t mclk_direction;
+
+	uint32_t mclk_rate;	/* MCLK frequency in Hz */
+	uint32_t fsync_rate;	/* FSYNC frequency in Hz */
+	uint32_t bclk_rate;	/* BCLK frequency in Hz */
+
+	/* TDM */
+	uint32_t tdm_slots;
+	uint32_t rx_slots;
+	uint32_t tx_slots;
+	uint16_t tdm_slot_width;
+	uint16_t reserved2;	/* alignment */
+} __packed;
+
+/* SAI Configuration Request - SOF_IPC_DAI_SAI_CONFIG */
+struct sof_ipc_dai_sai_params {
+	struct sof_ipc_hdr hdr;
+
+	/* MCLK */
+	uint16_t reserved1;
+	uint16_t mclk_id;
+	uint32_t mclk_direction;
+
+	uint32_t mclk_rate;	/* MCLK frequency in Hz */
+	uint32_t fsync_rate;	/* FSYNC frequency in Hz */
+	uint32_t bclk_rate;	/* BCLK frequency in Hz */
+
+	/* TDM */
+	uint32_t tdm_slots;
+	uint32_t rx_slots;
+	uint32_t tx_slots;
+	uint16_t tdm_slot_width;
+	uint16_t reserved2;	/* alignment */
+} __packed;
+
+/* MICFIL Configuration Request - SOF_IPC_DAI_MICFIL_CONFIG */
+struct sof_ipc_dai_micfil_params {
+	uint32_t pdm_rate;
+	uint32_t pdm_ch;
+} __packed;
+
+#endif