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, 64 insertions, 0 deletions

diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h
new file mode 100644
index 000000000..714d8f265
--- /dev/null
+++ b/include/acpi/acnames.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 */
+/******************************************************************************
+ *
+ * Name: acnames.h - Global names and strings
+ *
+ * Copyright (C) 2000 - 2026, Intel Corp.
+ *
+ *****************************************************************************/
+
+#ifndef __ACNAMES_H__
+#define __ACNAMES_H__
+
+/* Method names - these methods can appear anywhere in the namespace */
+
+#define METHOD_NAME__ADR        "_ADR"
+#define METHOD_NAME__AEI        "_AEI"
+#define METHOD_NAME__BBN        "_BBN"
+#define METHOD_NAME__CBA        "_CBA"
+#define METHOD_NAME__CID        "_CID"
+#define METHOD_NAME__CLS        "_CLS"
+#define METHOD_NAME__CRS        "_CRS"
+#define METHOD_NAME__DDN        "_DDN"
+#define METHOD_NAME__DIS        "_DIS"
+#define METHOD_NAME__DMA        "_DMA"
+#define METHOD_NAME__EVT        "_EVT"
+#define METHOD_NAME__HID        "_HID"
+#define METHOD_NAME__INI        "_INI"
+#define METHOD_NAME__PLD        "_PLD"
+#define METHOD_NAME__DSD        "_DSD"
+#define METHOD_NAME__PRS        "_PRS"
+#define METHOD_NAME__PRT        "_PRT"
+#define METHOD_NAME__PRW        "_PRW"
+#define METHOD_NAME__PS0        "_PS0"
+#define METHOD_NAME__PS1        "_PS1"
+#define METHOD_NAME__PS2        "_PS2"
+#define METHOD_NAME__PS3        "_PS3"
+#define METHOD_NAME__REG        "_REG"
+#define METHOD_NAME__SB_        "_SB_"
+#define METHOD_NAME__SEG        "_SEG"
+#define METHOD_NAME__SRS        "_SRS"
+#define METHOD_NAME__STA        "_STA"
+#define METHOD_NAME__SUB        "_SUB"
+#define METHOD_NAME__UID        "_UID"
+
+/* Method names - these methods must appear at the namespace root */
+
+#define METHOD_PATHNAME__PTS    "\\_PTS"
+#define METHOD_PATHNAME__SST    "\\_SI._SST"
+#define METHOD_PATHNAME__WAK    "\\_WAK"
+
+/* Definitions of the predefined namespace names  */
+
+#define ACPI_UNKNOWN_NAME       (u32) 0x3F3F3F3F	/* Unknown name is "????" */
+#define ACPI_PREFIX_MIXED       (u32) 0x69706341	/* "Acpi" */
+#define ACPI_PREFIX_LOWER       (u32) 0x69706361	/* "acpi" */
+
+/* Root name stuff */
+
+#define ACPI_ROOT_NAME          (u32) 0x5F5F5F5C	/* Root name is    "\___" */
+#define ACPI_ROOT_PATHNAME      "\\___"
+#define ACPI_NAMESPACE_ROOT     "Namespace Root"
+#define ACPI_NS_ROOT_PATH       "\\"
+
+#endif				/* __ACNAMES_H__  */