From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers 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 Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- drivers/fwctl/Kconfig | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 drivers/fwctl/Kconfig (limited to 'drivers/fwctl/Kconfig') diff --git a/drivers/fwctl/Kconfig b/drivers/fwctl/Kconfig new file mode 100644 index 000000000..d1b1925bd --- /dev/null +++ b/drivers/fwctl/Kconfig @@ -0,0 +1,44 @@ +# SPDX-License-Identifier: GPL-2.0-only +menuconfig FWCTL + tristate "fwctl device firmware access framework" + help + fwctl provides a userspace API for restricted access to communicate + with on-device firmware. The communication channel is intended to + support a wide range of lockdown compatible device behaviors including + manipulating device FLASH, debugging, and other activities that don't + fit neatly into an existing subsystem. + +if FWCTL +config FWCTL_BNXT + tristate "bnxt control fwctl driver" + depends on BNXT + help + BNXT provides interface for the user process to access the debug and + configuration registers of the Broadcom NIC hardware family. + This will allow configuration and debug tools to work out of the box on + mainstream kernel. + + If you don't know what to do here, say N. + +config FWCTL_MLX5 + tristate "mlx5 ConnectX control fwctl driver" + depends on MLX5_CORE + help + MLX5 provides interface for the user process to access the debug and + configuration registers of the ConnectX hardware family + (NICs, PCI switches and SmartNIC SoCs). + This will allow configuration and debug tools to work out of the box on + mainstream kernel. + + If you don't know what to do here, say N. + +config FWCTL_PDS + tristate "AMD/Pensando pds fwctl driver" + depends on PDS_CORE + help + The pds_fwctl driver provides an fwctl interface for a user process + to access the debug and configuration information of the AMD/Pensando + DSC hardware family. + + If you don't know what to do here, say N. +endif -- cgit v1.3.1