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, 38 insertions, 0 deletions

diff --git a/include/sound/wm8960.h b/include/sound/wm8960.h
new file mode 100644
index 000000000..275fd5b20
--- /dev/null
+++ b/include/sound/wm8960.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * wm8960.h  --  WM8960 Soc Audio driver platform data
+ */
+
+#ifndef _WM8960_PDATA_H
+#define _WM8960_PDATA_H
+
+#define WM8960_DRES_400R 0
+#define WM8960_DRES_200R 1
+#define WM8960_DRES_600R 2
+#define WM8960_DRES_150R 3
+#define WM8960_DRES_MAX  3
+
+struct wm8960_data {
+	bool capless;  /* Headphone outputs configured in capless mode */
+
+	bool shared_lrclk;  /* DAC and ADC LRCLKs are wired together */
+
+	/*
+	 * Setup for headphone detection
+	 *
+	 * hp_cfg[0]: HPSEL[1:0] of R48 (Additional Control 4)
+	 * hp_cfg[1]: {HPSWEN:HPSWPOL} of R24 (Additional Control 2).
+	 * hp_cfg[2]: {TOCLKSEL:TOEN} of R23 (Additional Control 1).
+	 */
+	u32 hp_cfg[3];
+
+	/*
+	 * Setup for gpio configuration
+	 *
+	 * gpio_cfg[0]: ALRCGPIO of R9 (Audio interface)
+	 * gpio_cfg[1]: {GPIOPOL:GPIOSEL[2:0]} of R48 (Additional Control 4).
+	 */
+	u32 gpio_cfg[2];
+};
+
+#endif