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, 77 insertions, 0 deletions

diff --git a/drivers/phy/freescale/Kconfig b/drivers/phy/freescale/Kconfig
new file mode 100644
index 000000000..5bf3864fb
--- /dev/null
+++ b/drivers/phy/freescale/Kconfig
@@ -0,0 +1,77 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+if (ARCH_MXC && ARM64) || COMPILE_TEST
+
+config PHY_FSL_IMX8MQ_USB
+	tristate "Freescale i.MX8M USB3 PHY"
+	depends on OF && HAS_IOMEM
+	depends on TYPEC || TYPEC=n
+	select GENERIC_PHY
+	default ARCH_MXC && ARM64
+
+config PHY_MIXEL_LVDS_PHY
+	tristate "Mixel LVDS PHY support"
+	depends on OF
+	select GENERIC_PHY
+	select REGMAP_MMIO
+	help
+	  Enable this to add support for the Mixel LVDS PHY as found
+	  on NXP's i.MX8qm SoC.
+
+config PHY_MIXEL_MIPI_DPHY
+	tristate "Mixel MIPI DSI PHY support"
+	depends on OF && HAS_IOMEM
+	select GENERIC_PHY
+	select GENERIC_PHY_MIPI_DPHY
+	select REGMAP_MMIO
+	help
+	  Enable this to add support for the Mixel DSI PHY as found
+	  on NXP's i.MX8 family of SOCs.
+
+config PHY_FSL_IMX8M_PCIE
+	tristate "Freescale i.MX8M PCIE PHY"
+	depends on OF && HAS_IOMEM
+	select GENERIC_PHY
+	help
+	  Enable this to add support for the PCIE PHY as found on
+	  i.MX8M family of SOCs.
+
+config PHY_FSL_IMX8QM_HSIO
+	tristate "Freescale i.MX8QM HSIO PHY"
+	depends on OF && HAS_IOMEM
+	select GENERIC_PHY
+	help
+	  Enable this to add support for the HSIO PHY as found on
+	  i.MX8QM family of SOCs.
+
+config PHY_FSL_SAMSUNG_HDMI_PHY
+	tristate "Samsung HDMI PHY support"
+	depends on OF && HAS_IOMEM && COMMON_CLK
+	help
+	  Enable this to add support for the Samsung HDMI PHY in i.MX8MP.
+endif
+
+config PHY_FSL_LYNX_CORE
+	tristate
+
+config PHY_FSL_LYNX_10G
+	tristate "Freescale Layerscape Lynx 10G SerDes PHY support"
+	depends on OF
+	depends on ARCH_LAYERSCAPE || COMPILE_TEST
+	select GENERIC_PHY
+	select PHY_FSL_LYNX_CORE
+	help
+	  Enable this to add support for the Lynx 10G SerDes PHY as found on
+	  NXP's Layerscape platform such as LS1088A or LS1028A.
+
+config PHY_FSL_LYNX_28G
+	tristate "Freescale Layerscape Lynx 28G SerDes PHY support"
+	depends on OF
+	depends on ARCH_LAYERSCAPE || COMPILE_TEST
+	select GENERIC_PHY
+	select PHY_FSL_LYNX_CORE
+	help
+	  Enable this to add support for the Lynx SerDes 28G PHY as
+	  found on NXP's Layerscape platforms such as LX2160A.
+	  Used to change the protocol running on SerDes lanes at runtime.
+	  Only useful for a restricted set of Ethernet protocols.