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, 206 insertions, 0 deletions

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
new file mode 100644
index 000000000..19f3b7d12
--- /dev/null
+++ b/drivers/phy/Kconfig
@@ -0,0 +1,206 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# PHY
+#
+
+menu "PHY Subsystem"
+
+config PHY_COMMON_PROPS
+	bool "PHY common properties" if KUNIT_ALL_TESTS
+	help
+	  This parses properties common between generic PHYs and Ethernet PHYs.
+
+	  Select this from consumer drivers to gain access to helpers for
+	  parsing properties from the
+	  Documentation/devicetree/bindings/phy/phy-common-props.yaml schema.
+
+config PHY_COMMON_PROPS_TEST
+	tristate "KUnit tests for PHY common props" if !KUNIT_ALL_TESTS
+	depends on KUNIT && PHY_COMMON_PROPS
+	default KUNIT_ALL_TESTS
+	help
+	  This builds KUnit tests for the PHY common property API.
+
+	  For more information on KUnit and unit tests in general,
+	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  When in doubt, say N.
+
+config GENERIC_PHY
+	bool "PHY Core"
+	help
+	  Generic PHY support.
+
+	  This framework is designed to provide a generic interface for PHY
+	  devices present in the kernel. This layer will have the generic
+	  API by which phy drivers can create PHY using the phy framework and
+	  phy users can obtain reference to the PHY. All the users of this
+	  framework should select this config.
+
+config GENERIC_PHY_MIPI_DPHY
+	bool
+	select GENERIC_PHY
+	help
+	  Generic MIPI D-PHY support.
+
+	  Provides a number of helpers a core functions for MIPI D-PHY
+	  drivers to us.
+
+config PHY_AIROHA_PCIE
+	tristate "Airoha PCIe-PHY Driver"
+	depends on ARCH_AIROHA || COMPILE_TEST
+	depends on OF
+	select GENERIC_PHY
+	help
+	  Say Y here to add support for Airoha PCIe PHY driver.
+	  This driver create the basic PHY instance and provides initialize
+	  callback for PCIe GEN3 port.
+
+config PHY_CAN_TRANSCEIVER
+	tristate "CAN transceiver PHY"
+	select GENERIC_PHY
+	select MULTIPLEXER
+	help
+	  This option enables support for CAN transceivers as a PHY. This
+	  driver provides function for putting the transceivers in various
+	  functional modes using gpios and sets the attribute max link
+	  rate, for CAN drivers.
+
+config PHY_EYEQ5_ETH
+	tristate "Ethernet PHY Driver on EyeQ5"
+	depends on OF
+	depends on MACH_EYEQ5 || COMPILE_TEST
+	select AUXILIARY_BUS
+	select GENERIC_PHY
+	default MACH_EYEQ5
+	help
+	  Enable this to support the Ethernet PHY integrated on EyeQ5.
+	  It supports both RGMII and SGMII. Registers are located in a
+	  shared register region called OLB. If M is selected, the
+	  module will be called phy-eyeq5-eth.
+
+config PHY_ECONET_PCIE
+	tristate "EcoNet PCIe-PHY Driver"
+	depends on ECONET || COMPILE_TEST
+	depends on OF
+	select GENERIC_PHY
+	select REGMAP_MMIO
+	help
+	  Say Y here to add support for EcoNet PCIe PHY driver.
+	  This driver create the basic PHY instance and provides initialize
+	  callback for PCIe GEN1 and GEN2 ports. This PHY is found on
+	  EcoNet SoCs including EN751221 and EN7528.
+
+config PHY_GOOGLE_USB
+	tristate "Google Tensor SoC USB PHY driver"
+	select GENERIC_PHY
+	depends on TYPEC
+	help
+	  Enable support for the USB PHY on Google Tensor SoCs, starting with
+	  the G5 generation (Laguna). This driver provides the PHY interfaces
+	  to interact with the SNPS eUSB2 and USB 3.2/DisplayPort Combo PHY,
+	  both of which are integrated with the DWC3 USB DRD controller.
+	  This driver currently supports USB high-speed.
+
+config USB_LGM_PHY
+	tristate "INTEL Lightning Mountain USB PHY Driver"
+	depends on USB_SUPPORT
+	depends on X86 || COMPILE_TEST
+	select USB_PHY
+	select REGULATOR
+	select REGULATOR_FIXED_VOLTAGE
+	help
+	  Enable this to support Intel DWC3 PHY USB phy. This driver provides
+	  interface to interact with USB GEN-II and USB 3.x PHY that is part
+	  of the Intel network SOC.
+
+config PHY_LPC18XX_USB_OTG
+	tristate "NXP LPC18xx/43xx SoC USB OTG PHY driver"
+	depends on OF && (ARCH_LPC18XX || COMPILE_TEST)
+	depends on MFD_SYSCON
+	select GENERIC_PHY
+	help
+	  Enable this to support NXP LPC18xx/43xx internal USB OTG PHY.
+
+	  This driver is need for USB0 support on LPC18xx/43xx and takes
+	  care of enabling and clock setup.
+
+config PHY_NXP_PTN3222
+	tristate "NXP PTN3222 1-port eUSB2 to USB2 redriver"
+	depends on I2C
+	depends on OF
+	select GENERIC_PHY
+	help
+	  Enable this to support NXP PTN3222 1-port eUSB2 to USB2 Redriver.
+	  This redriver performs translation between eUSB2 and USB2 signalling
+	  schemes. It supports all three USB 2.0 data rates: Low Speed, Full
+	  Speed and High Speed.
+
+config PHY_NXP_TJA1145
+	tristate "NXP TJA1145 CAN transceiver PHY"
+	select GENERIC_PHY
+	select REGMAP_SPI
+	depends on SPI
+	help
+	  This option enables support for NXPs TJA1145 CAN transceiver as a PHY.
+	  This driver provides function for putting the transceiver in various
+	  functional modes using SPI commands.
+
+config PHY_PISTACHIO_USB
+	tristate "IMG Pistachio USB2.0 PHY driver"
+	depends on MIPS || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Enable this to support the USB2.0 PHY on the IMG Pistachio SoC.
+
+config PHY_SNPS_EUSB2
+	tristate "SNPS eUSB2 PHY Driver"
+	depends on OF && (ARCH_EXYNOS || ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Enable support for the USB high-speed SNPS eUSB2 phy on select
+	  SoCs. The PHY is usually paired with a Synopsys DWC3 USB controller.
+
+config PHY_XGENE
+	tristate "APM X-Gene 15Gbps PHY support"
+	depends on HAS_IOMEM && OF && (ARCH_XGENE || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  This option enables support for APM X-Gene SoC multi-purpose PHY.
+
+source "drivers/phy/allwinner/Kconfig"
+source "drivers/phy/amlogic/Kconfig"
+source "drivers/phy/apple/Kconfig"
+source "drivers/phy/axiado/Kconfig"
+source "drivers/phy/broadcom/Kconfig"
+source "drivers/phy/cadence/Kconfig"
+source "drivers/phy/canaan/Kconfig"
+source "drivers/phy/eswin/Kconfig"
+source "drivers/phy/freescale/Kconfig"
+source "drivers/phy/hisilicon/Kconfig"
+source "drivers/phy/ingenic/Kconfig"
+source "drivers/phy/intel/Kconfig"
+source "drivers/phy/lantiq/Kconfig"
+source "drivers/phy/marvell/Kconfig"
+source "drivers/phy/mediatek/Kconfig"
+source "drivers/phy/microchip/Kconfig"
+source "drivers/phy/motorola/Kconfig"
+source "drivers/phy/mscc/Kconfig"
+source "drivers/phy/nuvoton/Kconfig"
+source "drivers/phy/qualcomm/Kconfig"
+source "drivers/phy/ralink/Kconfig"
+source "drivers/phy/realtek/Kconfig"
+source "drivers/phy/renesas/Kconfig"
+source "drivers/phy/rockchip/Kconfig"
+source "drivers/phy/samsung/Kconfig"
+source "drivers/phy/socionext/Kconfig"
+source "drivers/phy/sophgo/Kconfig"
+source "drivers/phy/spacemit/Kconfig"
+source "drivers/phy/st/Kconfig"
+source "drivers/phy/starfive/Kconfig"
+source "drivers/phy/sunplus/Kconfig"
+source "drivers/phy/tegra/Kconfig"
+source "drivers/phy/ti/Kconfig"
+source "drivers/phy/xilinx/Kconfig"
+
+endmenu