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/gpu/host1x/Kconfig | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 drivers/gpu/host1x/Kconfig (limited to 'drivers/gpu/host1x/Kconfig') diff --git a/drivers/gpu/host1x/Kconfig b/drivers/gpu/host1x/Kconfig new file mode 100644 index 000000000..e6c78ae20 --- /dev/null +++ b/drivers/gpu/host1x/Kconfig @@ -0,0 +1,30 @@ +# SPDX-License-Identifier: GPL-2.0-only + +config TEGRA_HOST1X_CONTEXT_BUS + bool + +config TEGRA_HOST1X + tristate "NVIDIA Tegra host1x driver" + depends on ARCH_TEGRA || COMPILE_TEST + select DMA_SHARED_BUFFER + select TEGRA_HOST1X_CONTEXT_BUS + select IOMMU_IOVA + help + Driver for the NVIDIA Tegra host1x hardware. + + The Tegra host1x module is the DMA engine for register access to + Tegra's graphics- and multimedia-related modules. The modules served + by host1x are referred to as clients. host1x includes some other + functionality, such as synchronization. + +if TEGRA_HOST1X + +config TEGRA_HOST1X_FIREWALL + bool "Enable HOST1X security firewall" + default y + help + Say yes if kernel should protect command streams from tampering. + + If unsure, choose Y. + +endif -- cgit v1.3.1