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, 151 insertions, 0 deletions

diff --git a/include/sound/sof/stream.h b/include/sound/sof/stream.h
new file mode 100644
index 000000000..1bb25487d
--- /dev/null
+++ b/include/sound/sof/stream.h
@@ -0,0 +1,151 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * Copyright(c) 2018 Intel Corporation
+ */
+
+#ifndef __INCLUDE_SOUND_SOF_STREAM_H__
+#define __INCLUDE_SOUND_SOF_STREAM_H__
+
+#include <sound/sof/header.h>
+
+/*
+ * Stream configuration.
+ */
+
+#define SOF_IPC_MAX_CHANNELS			8
+
+/* common sample rates for use in masks */
+#define SOF_RATE_8000		(1 <<  0) /**< 8000Hz  */
+#define SOF_RATE_11025		(1 <<  1) /**< 11025Hz */
+#define SOF_RATE_12000		(1 <<  2) /**< 12000Hz */
+#define SOF_RATE_16000		(1 <<  3) /**< 16000Hz */
+#define SOF_RATE_22050		(1 <<  4) /**< 22050Hz */
+#define SOF_RATE_24000		(1 <<  5) /**< 24000Hz */
+#define SOF_RATE_32000		(1 <<  6) /**< 32000Hz */
+#define SOF_RATE_44100		(1 <<  7) /**< 44100Hz */
+#define SOF_RATE_48000		(1 <<  8) /**< 48000Hz */
+#define SOF_RATE_64000		(1 <<  9) /**< 64000Hz */
+#define SOF_RATE_88200		(1 << 10) /**< 88200Hz */
+#define SOF_RATE_96000		(1 << 11) /**< 96000Hz */
+#define SOF_RATE_176400		(1 << 12) /**< 176400Hz */
+#define SOF_RATE_192000		(1 << 13) /**< 192000Hz */
+
+/* continuous and non-standard rates for flexibility */
+#define SOF_RATE_CONTINUOUS	(1 << 30)  /**< range */
+#define SOF_RATE_KNOT		(1 << 31)  /**< non-continuous */
+
+/* generic PCM flags for runtime settings */
+#define SOF_PCM_FLAG_XRUN_STOP	(1 << 0) /**< Stop on any XRUN */
+
+/* stream PCM frame format */
+enum sof_ipc_frame {
+	SOF_IPC_FRAME_S16_LE = 0,
+	SOF_IPC_FRAME_S24_4LE,
+	SOF_IPC_FRAME_S32_LE,
+	SOF_IPC_FRAME_FLOAT,
+	/* other formats here */
+};
+
+/* stream buffer format */
+enum sof_ipc_buffer_format {
+	SOF_IPC_BUFFER_INTERLEAVED,
+	SOF_IPC_BUFFER_NONINTERLEAVED,
+	/* other formats here */
+};
+
+/* stream direction */
+enum sof_ipc_stream_direction {
+	SOF_IPC_STREAM_PLAYBACK = 0,
+	SOF_IPC_STREAM_CAPTURE,
+};
+
+/* stream ring info */
+struct sof_ipc_host_buffer {
+	struct sof_ipc_hdr hdr;
+	uint32_t phy_addr;
+	uint32_t pages;
+	uint32_t size;
+	uint32_t reserved[3];
+} __packed;
+
+struct sof_ipc_stream_params {
+	struct sof_ipc_hdr hdr;
+	struct sof_ipc_host_buffer buffer;
+	uint32_t direction;	/**< enum sof_ipc_stream_direction */
+	uint32_t frame_fmt;	/**< enum sof_ipc_frame */
+	uint32_t buffer_fmt;	/**< enum sof_ipc_buffer_format */
+	uint32_t rate;
+	uint16_t stream_tag;
+	uint16_t channels;
+	uint16_t sample_valid_bytes;
+	uint16_t sample_container_bytes;
+
+	uint32_t host_period_bytes;
+	uint16_t no_stream_position; /**< 1 means don't send stream position */
+	uint8_t cont_update_posn; /**< 1 means continuous update stream position */
+	uint8_t reserved0;
+	int16_t ext_data_length; /**< 0, means no extended data */
+	uint8_t reserved[2];
+	uint16_t chmap[SOF_IPC_MAX_CHANNELS];	/**< channel map - SOF_CHMAP_ */
+	uint8_t ext_data[]; /**< extended data */
+} __packed;
+
+/* PCM params info - SOF_IPC_STREAM_PCM_PARAMS */
+struct sof_ipc_pcm_params {
+	struct sof_ipc_cmd_hdr hdr;
+	uint32_t comp_id;
+	uint32_t flags;		/**< generic PCM flags - SOF_PCM_FLAG_ */
+	uint32_t reserved[2];
+	struct sof_ipc_stream_params params;
+}  __packed;
+
+/* PCM params info reply - SOF_IPC_STREAM_PCM_PARAMS_REPLY */
+struct sof_ipc_pcm_params_reply {
+	struct sof_ipc_reply rhdr;
+	uint32_t comp_id;
+	uint32_t posn_offset;
+} __packed;
+
+/* free stream - SOF_IPC_STREAM_PCM_PARAMS */
+struct sof_ipc_stream {
+	struct sof_ipc_cmd_hdr hdr;
+	uint32_t comp_id;
+} __packed;
+
+/* flags indicating which time stamps are in sync with each other */
+#define	SOF_TIME_HOST_SYNC	(1 << 0)
+#define	SOF_TIME_DAI_SYNC	(1 << 1)
+#define	SOF_TIME_WALL_SYNC	(1 << 2)
+#define	SOF_TIME_STAMP_SYNC	(1 << 3)
+
+/* flags indicating which time stamps are valid */
+#define	SOF_TIME_HOST_VALID	(1 << 8)
+#define	SOF_TIME_DAI_VALID	(1 << 9)
+#define	SOF_TIME_WALL_VALID	(1 << 10)
+#define	SOF_TIME_STAMP_VALID	(1 << 11)
+
+/* flags indicating time stamps are 64bit else 3use low 32bit */
+#define	SOF_TIME_HOST_64	(1 << 16)
+#define	SOF_TIME_DAI_64		(1 << 17)
+#define	SOF_TIME_WALL_64	(1 << 18)
+#define	SOF_TIME_STAMP_64	(1 << 19)
+
+struct sof_ipc_stream_posn {
+	struct sof_ipc_reply rhdr;
+	uint32_t comp_id;	/**< host component ID */
+	uint32_t flags;		/**< SOF_TIME_ */
+	uint32_t wallclock_hz;	/**< frequency of wallclock in Hz */
+	uint32_t timestamp_ns;	/**< resolution of timestamp in ns */
+	uint64_t host_posn;	/**< host DMA position in bytes */
+	uint64_t dai_posn;	/**< DAI DMA position in bytes */
+	uint64_t comp_posn;	/**< comp position in bytes */
+	uint64_t wallclock;	/**< audio wall clock */
+	uint64_t timestamp;	/**< system time stamp */
+	uint32_t xrun_comp_id;	/**< comp ID of XRUN component */
+	int32_t xrun_size;	/**< XRUN size in bytes */
+}  __packed;
+
+#endif