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, 60 insertions, 0 deletions

diff --git a/drivers/phy/st/Kconfig b/drivers/phy/st/Kconfig
new file mode 100644
index 000000000..49206185e
--- /dev/null
+++ b/drivers/phy/st/Kconfig
@@ -0,0 +1,60 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Phy drivers for STMicro platforms
+#
+config PHY_MIPHY28LP
+	tristate "STMicroelectronics MIPHY28LP PHY driver for STiH407"
+	depends on ARCH_STI || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Enable this to support the miphy transceiver (for SATA/PCIE/USB3)
+	  that is part of STMicroelectronics STiH407 SoC.
+
+config PHY_ST_SPEAR1310_MIPHY
+	tristate "ST SPEAR1310-MIPHY driver"
+	select GENERIC_PHY
+	depends on MACH_SPEAR1310 || COMPILE_TEST
+	help
+	  Support for ST SPEAr1310 MIPHY which can be used for PCIe and SATA.
+
+config PHY_ST_SPEAR1340_MIPHY
+	tristate "ST SPEAR1340-MIPHY driver"
+	select GENERIC_PHY
+	depends on MACH_SPEAR1340 || COMPILE_TEST
+	help
+	  Support for ST SPEAr1340 MIPHY which can be used for PCIe and SATA.
+
+config PHY_STIH407_USB
+	tristate "STMicroelectronics USB2 picoPHY driver for STiH407 family"
+	depends on RESET_CONTROLLER
+	depends on ARCH_STI || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Enable this support to enable the picoPHY device used by USB2
+	  and USB3 controllers on STMicroelectronics STiH407 SoC families.
+
+config PHY_STM32_COMBOPHY
+	tristate "STMicroelectronics COMBOPHY driver for STM32MP25"
+	depends on ARCH_STM32 || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Enable this to support the COMBOPHY device used by USB3 or PCIe
+	  controllers on STMicroelectronics STM32MP25 SoC.
+	  This driver controls the COMBOPHY block to generate the PCIe 100Mhz
+	  reference clock from either the external clock generator or HSE
+	  internal SoC clock source.
+
+config PHY_STM32_USBPHYC
+	tristate "STMicroelectronics STM32 USB HS PHY Controller driver"
+	depends on ARCH_STM32 || COMPILE_TEST
+	depends on COMMON_CLK
+	select GENERIC_PHY
+	help
+	  Enable this to support the High-Speed USB transceivers that are part
+	  of some STMicroelectronics STM32 SoCs.
+
+	  This driver controls the entire USB PHY block: the USB PHY controller
+	  (USBPHYC) and the two 8-bit wide UTMI+ interfaces. First interface is
+	  used by an HS USB Host controller, and the second one is shared
+	  between an HS USB OTG controller and an HS USB Host controller,
+	  selected by a USB switch.