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, 175 insertions, 0 deletions

diff --git a/drivers/pinctrl/intel/Kconfig b/drivers/pinctrl/intel/Kconfig
new file mode 100644
index 000000000..04c3a5b58
--- /dev/null
+++ b/drivers/pinctrl/intel/Kconfig
@@ -0,0 +1,175 @@
+# SPDX-License-Identifier: GPL-2.0
+# Intel pin control drivers
+menu "Intel pinctrl drivers"
+	depends on (ACPI && X86) || COMPILE_TEST
+
+config PINCTRL_BAYTRAIL
+	bool "Intel Baytrail GPIO pin control"
+	select PINCTRL_INTEL
+	help
+	  driver for memory mapped GPIO functionality on Intel Baytrail
+	  platforms. Supports 3 banks with 102, 28 and 44 gpios.
+	  Most pins are usually muxed to some other functionality by firmware,
+	  so only a small amount is available for gpio use.
+
+	  Requires ACPI device enumeration code to set up a platform device.
+
+config PINCTRL_CHERRYVIEW
+	tristate "Intel Cherryview/Braswell pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  Cherryview/Braswell pinctrl driver provides an interface that
+	  allows configuring of SoC pins and using them as GPIOs.
+
+config PINCTRL_LYNXPOINT
+	tristate "Intel Lynxpoint pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  Lynxpoint is the PCH of Intel Haswell. This pinctrl driver
+	  provides an interface that allows configuring of PCH pins and
+	  using them as GPIOs.
+
+config PINCTRL_INTEL
+	tristate
+	select PINMUX
+	select PINCONF
+	select GENERIC_PINCONF
+	select GPIOLIB
+	select GPIOLIB_IRQCHIP
+
+config PINCTRL_INTEL_PLATFORM
+	tristate "Intel pinctrl and GPIO platform driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel PCH pins and using them as GPIOs. Currently the following
+	  Intel SoCs / platforms require this to be functional:
+	  - Lunar Lake
+	  - Nova Lake
+	  - Panther Lake
+
+config PINCTRL_ALDERLAKE
+	tristate "Intel Alder Lake pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  PCH pins of the following platforms and using them as GPIOs:
+	  - Alder Lake HX, N, and S
+	  - Raptor Lake HX, E, and S
+	  - Twin Lake
+
+config PINCTRL_BROXTON
+	tristate "Intel Broxton pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  Broxton pinctrl driver provides an interface that allows
+	  configuring of SoC pins and using them as GPIOs.
+
+config PINCTRL_CANNONLAKE
+	tristate "Intel Cannon Lake PCH pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Cannon Lake PCH pins and using them as GPIOs.
+
+config PINCTRL_CEDARFORK
+	tristate "Intel Cedar Fork pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Cedar Fork PCH pins and using them as GPIOs.
+
+config PINCTRL_DENVERTON
+	tristate "Intel Denverton pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Denverton SoC pins and using them as GPIOs.
+
+config PINCTRL_ELKHARTLAKE
+	tristate "Intel Elkhart Lake SoC pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Elkhart Lake SoC pins and using them as GPIOs.
+
+config PINCTRL_EMMITSBURG
+	tristate "Intel Emmitsburg pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Emmitsburg pins and using them as GPIOs.
+
+config PINCTRL_GEMINILAKE
+	tristate "Intel Gemini Lake SoC pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Gemini Lake SoC pins and using them as GPIOs.
+
+config PINCTRL_ICELAKE
+	tristate "Intel Ice Lake PCH pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Ice Lake PCH pins and using them as GPIOs.
+
+config PINCTRL_JASPERLAKE
+	tristate "Intel Jasper Lake PCH pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Jasper Lake PCH pins and using them as GPIOs.
+
+config PINCTRL_LAKEFIELD
+	tristate "Intel Lakefield SoC pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Lakefield SoC pins and using them as GPIOs.
+
+config PINCTRL_LEWISBURG
+	tristate "Intel Lewisburg pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  of Intel Lewisburg pins and using them as GPIOs.
+
+config PINCTRL_METEORLAKE
+	tristate "Intel Meteor Lake pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  SoC pins of the following platforms and using them as GPIOs:
+	  - Arrow Lake (all variants)
+	  - Meteor Lake (all variants)
+
+config PINCTRL_METEORPOINT
+	tristate "Intel Meteor Point pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  PCH pins of the following platforms and using them as GPIOs:
+	  - Arrow Lake HX and S
+
+config PINCTRL_SUNRISEPOINT
+	tristate "Intel Sunrisepoint pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  Sunrisepoint is the PCH of Intel Skylake. This pinctrl driver
+	  provides an interface that allows configuring of PCH pins and
+	  using them as GPIOs.
+
+config PINCTRL_TIGERLAKE
+	tristate "Intel Tiger Lake pinctrl and GPIO driver"
+	select PINCTRL_INTEL
+	help
+	  This pinctrl driver provides an interface that allows configuring
+	  PCH pins of the following platforms and using them as GPIOs:
+	  - Alder Lake H, P, PS, and U
+	  - Raptor Lake H, P, PS, PX, and U
+	  - Rocket Lake S
+	  - Tiger Lake (all variants)
+
+source "drivers/pinctrl/intel/Kconfig.tng"
+endmenu