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, 82 insertions, 0 deletions

diff --git a/include/dt-bindings/clock/sh73a0-clock.h b/include/dt-bindings/clock/sh73a0-clock.h
new file mode 100644
index 000000000..5b544ad7f
--- /dev/null
+++ b/include/dt-bindings/clock/sh73a0-clock.h
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright 2014 Ulrich Hecht
+ */
+
+#ifndef __DT_BINDINGS_CLOCK_SH73A0_H__
+#define __DT_BINDINGS_CLOCK_SH73A0_H__
+
+/* CPG */
+#define SH73A0_CLK_MAIN		0
+#define SH73A0_CLK_PLL0		1
+#define SH73A0_CLK_PLL1		2
+#define SH73A0_CLK_PLL2		3
+#define SH73A0_CLK_PLL3		4
+#define SH73A0_CLK_DSI0PHY	5
+#define SH73A0_CLK_DSI1PHY	6
+#define SH73A0_CLK_ZG		7
+#define SH73A0_CLK_M3		8
+#define SH73A0_CLK_B		9
+#define SH73A0_CLK_M1		10
+#define SH73A0_CLK_M2		11
+#define SH73A0_CLK_Z		12
+#define SH73A0_CLK_ZX		13
+#define SH73A0_CLK_HP		14
+
+/* MSTP0 */
+#define SH73A0_CLK_IIC2		1
+#define SH73A0_CLK_MSIOF0	0
+
+/* MSTP1 */
+#define SH73A0_CLK_CEU1		29
+#define SH73A0_CLK_CSI2_RX1	28
+#define SH73A0_CLK_CEU0		27
+#define SH73A0_CLK_CSI2_RX0	26
+#define SH73A0_CLK_TMU0		25
+#define SH73A0_CLK_DSITX0	18
+#define SH73A0_CLK_IIC0		16
+#define SH73A0_CLK_SGX		12
+#define SH73A0_CLK_LCDC0	0
+
+/* MSTP2 */
+#define SH73A0_CLK_SCIFA7	19
+#define SH73A0_CLK_SY_DMAC	18
+#define SH73A0_CLK_MP_DMAC	17
+#define SH73A0_CLK_MSIOF3	15
+#define SH73A0_CLK_MSIOF1	8
+#define SH73A0_CLK_SCIFA5	7
+#define SH73A0_CLK_SCIFB	6
+#define SH73A0_CLK_MSIOF2	5
+#define SH73A0_CLK_SCIFA0	4
+#define SH73A0_CLK_SCIFA1	3
+#define SH73A0_CLK_SCIFA2	2
+#define SH73A0_CLK_SCIFA3	1
+#define SH73A0_CLK_SCIFA4	0
+
+/* MSTP3 */
+#define SH73A0_CLK_SCIFA6	31
+#define SH73A0_CLK_CMT1		29
+#define SH73A0_CLK_FSI		28
+#define SH73A0_CLK_IRDA		25
+#define SH73A0_CLK_IIC1		23
+#define SH73A0_CLK_USB		22
+#define SH73A0_CLK_FLCTL	15
+#define SH73A0_CLK_SDHI0	14
+#define SH73A0_CLK_SDHI1	13
+#define SH73A0_CLK_MMCIF0	12
+#define SH73A0_CLK_SDHI2	11
+#define SH73A0_CLK_TPU0		4
+#define SH73A0_CLK_TPU1		3
+#define SH73A0_CLK_TPU2		2
+#define SH73A0_CLK_TPU3		1
+#define SH73A0_CLK_TPU4		0
+
+/* MSTP4 */
+#define SH73A0_CLK_IIC3		11
+#define SH73A0_CLK_IIC4		10
+#define SH73A0_CLK_KEYSC	3
+
+/* MSTP5 */
+#define SH73A0_CLK_INTCA0	8
+
+#endif