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, 117 insertions, 0 deletions

diff --git a/drivers/phy/broadcom/Kconfig b/drivers/phy/broadcom/Kconfig
new file mode 100644
index 000000000..46371a894
--- /dev/null
+++ b/drivers/phy/broadcom/Kconfig
@@ -0,0 +1,117 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Phy drivers for Broadcom platforms
+#
+menu "PHY drivers for Broadcom platforms"
+
+config PHY_BCM63XX_USBH
+	tristate "BCM63xx USBH PHY driver"
+	depends on BMIPS_GENERIC || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Enable this to support the BCM63xx USBH PHY driver.
+	  If unsure, say N.
+
+config PHY_CYGNUS_PCIE
+	tristate "Broadcom Cygnus PCIe PHY driver"
+	depends on OF && (ARCH_BCM_CYGNUS || COMPILE_TEST)
+	select GENERIC_PHY
+	default ARCH_BCM_CYGNUS
+	help
+	  Enable this to support the Broadcom Cygnus PCIe PHY.
+	  If unsure, say N.
+
+config PHY_BCM_SR_USB
+	tristate "Broadcom Stingray USB PHY driver"
+	depends on OF && (ARCH_BCM_IPROC || COMPILE_TEST)
+	select GENERIC_PHY
+	default ARCH_BCM_IPROC
+	help
+	  Enable this to support the Broadcom Stingray USB PHY
+	  driver. It supports all versions of Superspeed and
+	  Highspeed PHYs.
+	  If unsure, say N.
+
+config BCM_KONA_USB2_PHY
+	tristate "Broadcom Kona USB2 PHY Driver"
+	depends on HAS_IOMEM
+	select GENERIC_PHY
+	help
+	  Enable this to support the Broadcom Kona USB 2.0 PHY.
+
+config PHY_BCM_NS_USB2
+	tristate "Broadcom Northstar USB 2.0 PHY Driver"
+	depends on ARCH_BCM_IPROC || COMPILE_TEST
+	depends on HAS_IOMEM && OF
+	select GENERIC_PHY
+	help
+	  Enable this to support Broadcom USB 2.0 PHY connected to the USB
+	  controller on Northstar family.
+
+config PHY_BCM_NS_USB3
+	tristate "Broadcom Northstar USB 3.0 PHY Driver"
+	depends on ARCH_BCM_IPROC || COMPILE_TEST
+	depends on HAS_IOMEM && OF
+	depends on PHYLIB
+	select GENERIC_PHY
+	help
+	  Enable this to support Broadcom USB 3.0 PHY connected to the USB
+	  controller on Northstar family.
+
+config PHY_NS2_PCIE
+	tristate "Broadcom Northstar2 PCIe PHY driver"
+	depends on (OF && MDIO_BUS_MUX_BCM_IPROC) || (COMPILE_TEST && PHYLIB)
+	select GENERIC_PHY
+	default ARCH_BCM_IPROC
+	help
+	  Enable this to support the Broadcom Northstar2 PCIe PHY.
+	  If unsure, say N.
+
+config PHY_NS2_USB_DRD
+	tristate "Broadcom Northstar2 USB DRD PHY support"
+	depends on OF && (ARCH_BCM_IPROC || COMPILE_TEST)
+	select GENERIC_PHY
+	select EXTCON
+	default ARCH_BCM_IPROC
+	help
+	  Enable this to support the Broadcom Northstar2 USB DRD PHY.
+	  This driver initializes the PHY in either HOST or DEVICE mode.
+	  The host or device configuration is read from device tree.
+
+	  If unsure, say N.
+
+config PHY_BRCM_SATA
+	tristate "Broadcom SATA PHY driver"
+	depends on ARCH_BRCMSTB || ARCH_BCM_IPROC || BMIPS_GENERIC || \
+		   ARCH_BCMBCA || COMPILE_TEST
+	depends on OF
+	select GENERIC_PHY
+	default ARCH_BCM_IPROC
+	help
+	  Enable this to support the Broadcom SATA PHY.
+	  If unsure, say N.
+
+config PHY_BRCM_USB
+	tristate "Broadcom STB USB PHY driver"
+	depends on ARCH_BCMBCA || ARCH_BRCMSTB || COMPILE_TEST
+	depends on OF
+	select GENERIC_PHY
+	select SOC_BRCMSTB if ARCH_BRCMSTB
+	default ARCH_BCMBCA || ARCH_BRCMSTB
+	help
+	  Enable this to support the Broadcom STB USB PHY.
+	  This driver is required by the USB XHCI, EHCI and OHCI
+	  drivers.
+	  If unsure, say N.
+
+config PHY_BCM_SR_PCIE
+	tristate "Broadcom Stingray PCIe PHY driver"
+	depends on OF && (ARCH_BCM_IPROC || COMPILE_TEST)
+	select GENERIC_PHY
+	select MFD_SYSCON
+	default ARCH_BCM_IPROC
+	help
+	  Enable this to support the Broadcom Stingray PCIe PHY
+	  If unsure, say N.
+
+endmenu