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, 56 insertions, 0 deletions

diff --git a/sound/hda/controllers/Kconfig b/sound/hda/controllers/Kconfig
new file mode 100644
index 000000000..5d6a77e68
--- /dev/null
+++ b/sound/hda/controllers/Kconfig
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SND_HDA_INTEL
+	tristate "HD Audio PCI"
+	depends on PCI
+	select SND_HDA
+	select SND_INTEL_DSP_CONFIG
+	help
+	  Say Y here to include support for Intel "High Definition
+	  Audio" (Azalia) and its compatible devices.
+
+	  This option enables the HD-audio controller.  Don't forget
+	  to choose the appropriate HD-audio codec options.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-hda-intel.
+
+config SND_HDA_TEGRA
+	tristate "NVIDIA Tegra HD Audio"
+	depends on ARCH_TEGRA
+	select SND_HDA
+	select SND_HDA_ALIGNED_MMIO
+	help
+	  Say Y here to support the HDA controller present in NVIDIA
+	  Tegra SoCs
+
+	  This options enables support for the HD Audio controller
+	  present in some NVIDIA Tegra SoCs, used to communicate audio
+	  to the HDMI output.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-hda-tegra.
+
+config SND_HDA_CIX_IPBLOQ
+	tristate "CIX IPBLOQ HD Audio"
+	depends on ARCH_CIX || COMPILE_TEST
+	select SND_HDA
+	select SND_HDA_ALIGNED_MMIO
+	help
+	  Say Y here to support the HDA controller present in CIX SoCs
+
+	  This options enables support for the HD Audio controller
+	  present in some CIX SoCs.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-hda-cix-ipbloq.
+
+config SND_HDA_ACPI
+	tristate "HD Audio ACPI"
+	depends on ACPI
+	select SND_HDA
+	help
+	  Say Y here to include support for Azalia-compatible HDA controllers
+	  which are advertised via ACPI objects.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-hda-acpi.