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/hte/Kconfig | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 drivers/hte/Kconfig (limited to 'drivers/hte/Kconfig') diff --git a/drivers/hte/Kconfig b/drivers/hte/Kconfig new file mode 100644 index 000000000..f57bad67d --- /dev/null +++ b/drivers/hte/Kconfig @@ -0,0 +1,34 @@ +# SPDX-License-Identifier: GPL-2.0-only +menuconfig HTE + bool "Hardware Timestamping Engine (HTE) Support" + help + Hardware Timestamping Engine (HTE) Support. + + Some devices provide a hardware timestamping engine which can + timestamp certain device lines/signals in realtime. It comes with a + benefit for the applications needing accurate timestamping event with + less jitter. This framework provides a generic interface to such HTE + providers and consumer devices. + + If unsure, say no. + +if HTE + +config HTE_TEGRA194 + tristate "NVIDIA Tegra194 HTE Support" + depends on (ARCH_TEGRA || COMPILE_TEST) + depends on GPIOLIB + help + Enable this option for integrated hardware timestamping engine also + known as generic timestamping engine (GTE) support on NVIDIA Tegra194 + and later systems-on-chip. The driver supports 352 LIC IRQs and 39 + AON GPIOs lines for timestamping in realtime. + +config HTE_TEGRA194_TEST + tristate "NVIDIA Tegra194 HTE Test" + depends on (HTE_TEGRA194 || COMPILE_TEST) + help + The NVIDIA Tegra194 GTE test driver demonstrates how to use HTE + framework to timestamp GPIO and LIC IRQ lines. + +endif -- cgit v1.3.1