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/cdx/controller/mcdid.h | 63 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 drivers/cdx/controller/mcdid.h (limited to 'drivers/cdx/controller/mcdid.h') diff --git a/drivers/cdx/controller/mcdid.h b/drivers/cdx/controller/mcdid.h new file mode 100644 index 000000000..7fc29f099 --- /dev/null +++ b/drivers/cdx/controller/mcdid.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Copyright 2008-2013 Solarflare Communications Inc. + * Copyright (C) 2022-2025, Advanced Micro Devices, Inc. + */ + +#ifndef CDX_MCDID_H +#define CDX_MCDID_H + +#include +#include +#include + +#include "mc_cdx_pcol.h" + +#ifdef DEBUG +#define CDX_WARN_ON_ONCE_PARANOID(x) WARN_ON_ONCE(x) +#define CDX_WARN_ON_PARANOID(x) WARN_ON(x) +#else +#define CDX_WARN_ON_ONCE_PARANOID(x) do {} while (0) +#define CDX_WARN_ON_PARANOID(x) do {} while (0) +#endif + +#define MCDI_BUF_LEN (8 + MCDI_CTL_SDU_LEN_MAX) + +static inline struct cdx_mcdi_iface *cdx_mcdi_if(struct cdx_mcdi *cdx) +{ + return cdx->mcdi ? &cdx->mcdi->iface : NULL; +} + +int cdx_mcdi_rpc_async(struct cdx_mcdi *cdx, unsigned int cmd, + const struct cdx_dword *inbuf, size_t inlen, + cdx_mcdi_async_completer *complete, + unsigned long cookie); +int cdx_mcdi_wait_for_quiescence(struct cdx_mcdi *cdx, + unsigned int timeout_jiffies); + +/* + * We expect that 16- and 32-bit fields in MCDI requests and responses + * are appropriately aligned, but 64-bit fields are only + * 32-bit-aligned. + */ +#define MCDI_BYTE(_buf, _field) \ + ((void)BUILD_BUG_ON_ZERO(MC_CMD_ ## _field ## _LEN != 1), \ + *MCDI_PTR(_buf, _field)) +#define MCDI_WORD(_buf, _field) \ + ((void)BUILD_BUG_ON_ZERO(MC_CMD_ ## _field ## _LEN != 2), \ + le16_to_cpu(*(__force const __le16 *)MCDI_PTR(_buf, _field))) +#define MCDI_POPULATE_DWORD_1(_buf, _field, _name1, _value1) \ + CDX_POPULATE_DWORD_1(*_MCDI_DWORD(_buf, _field), \ + MC_CMD_ ## _name1, _value1) +#define MCDI_SET_QWORD(_buf, _field, _value) \ + do { \ + CDX_POPULATE_DWORD_1(_MCDI_DWORD(_buf, _field)[0], \ + CDX_DWORD, (u32)(_value)); \ + CDX_POPULATE_DWORD_1(_MCDI_DWORD(_buf, _field)[1], \ + CDX_DWORD, (u64)(_value) >> 32); \ + } while (0) +#define MCDI_QWORD(_buf, _field) \ + (CDX_DWORD_FIELD(_MCDI_DWORD(_buf, _field)[0], CDX_DWORD) | \ + (u64)CDX_DWORD_FIELD(_MCDI_DWORD(_buf, _field)[1], CDX_DWORD) << 32) + +#endif /* CDX_MCDID_H */ -- cgit v1.3.1