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 --- include/acpi/pcc.h | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 include/acpi/pcc.h (limited to 'include/acpi/pcc.h') diff --git a/include/acpi/pcc.h b/include/acpi/pcc.h new file mode 100644 index 000000000..840bfc95b --- /dev/null +++ b/include/acpi/pcc.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * PCC (Platform Communications Channel) methods + */ + +#ifndef _PCC_H +#define _PCC_H + +#include +#include + +struct pcc_mbox_chan { + struct mbox_chan *mchan; + u64 shmem_base_addr; + void __iomem *shmem; + u64 shmem_size; + u32 latency; + u32 max_access_rate; + u16 min_turnaround_time; +}; + +/* Generic Communications Channel Shared Memory Region */ +#define PCC_SIGNATURE 0x50434300 +/* Generic Communications Channel Command Field */ +#define PCC_CMD_GENERATE_DB_INTR BIT(15) +/* Generic Communications Channel Status Field */ +#define PCC_STATUS_CMD_COMPLETE BIT(0) +#define PCC_STATUS_SCI_DOORBELL BIT(1) +#define PCC_STATUS_ERROR BIT(2) +#define PCC_STATUS_PLATFORM_NOTIFY BIT(3) +/* Initiator Responder Communications Channel Flags */ +#define PCC_CMD_COMPLETION_NOTIFY BIT(0) + +#define MAX_PCC_SUBSPACES 256 + +#ifdef CONFIG_PCC +extern struct pcc_mbox_chan * +pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id); +extern void pcc_mbox_free_channel(struct pcc_mbox_chan *chan); +#else +static inline struct pcc_mbox_chan * +pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id) +{ + return ERR_PTR(-ENODEV); +} +static inline void pcc_mbox_free_channel(struct pcc_mbox_chan *chan) { } +#endif + +#endif /* _PCC_H */ -- cgit v1.3.1