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, 55 insertions, 0 deletions

diff --git a/drivers/memstick/host/Kconfig b/drivers/memstick/host/Kconfig
new file mode 100644
index 000000000..fcd2c2cc3
--- /dev/null
+++ b/drivers/memstick/host/Kconfig
@@ -0,0 +1,55 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# MemoryStick host controller drivers
+#
+
+comment "MemoryStick Host Controller Drivers"
+
+config MEMSTICK_TIFM_MS
+	tristate "TI Flash Media MemoryStick Interface support "
+	depends on PCI
+	select TIFM_CORE
+	help
+	  Say Y here if you want to be able to access MemoryStick cards with
+	  the Texas Instruments(R) Flash Media card reader, found in many
+	  laptops.
+	  This option 'selects' (turns on, enables) 'TIFM_CORE', but you
+	  probably also need appropriate card reader host adapter, such as
+	  'Misc devices: TI Flash Media PCI74xx/PCI76xx host adapter support
+	  (TIFM_7XX1)'.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called tifm_ms.
+
+config MEMSTICK_JMICRON_38X
+	tristate "JMicron JMB38X MemoryStick interface support"
+	depends on PCI
+
+	help
+	  Say Y here if you want to be able to access MemoryStick cards with
+	  the JMicron(R) JMB38X MemoryStick card reader.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called jmb38x_ms.
+
+config MEMSTICK_R592
+	tristate "Ricoh R5C592 MemoryStick interface support"
+	depends on PCI
+
+	help
+	  Say Y here if you want to be able to access MemoryStick cards with
+	  the Ricoh R5C592 MemoryStick card reader (which is part of 5 in one
+		multifunction reader)
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called r592.
+
+config MEMSTICK_REALTEK_USB
+	tristate "Realtek USB Memstick Card Interface Driver"
+	depends on MISC_RTSX_USB
+	help
+	  Say Y here to include driver code to support Memstick card interface
+	  of Realtek RTS5129/39 series USB card reader
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called rts5139_ms.