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/rpmsg/rpmsg_internal.h | 96 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 drivers/rpmsg/rpmsg_internal.h (limited to 'drivers/rpmsg/rpmsg_internal.h') diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h new file mode 100644 index 000000000..a8b7065fd --- /dev/null +++ b/drivers/rpmsg/rpmsg_internal.h @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * remote processor messaging bus internals + * + * Copyright (C) 2011 Texas Instruments, Inc. + * Copyright (C) 2011 Google, Inc. + * + * Ohad Ben-Cohen + * Brian Swetland + */ + +#ifndef __RPMSG_INTERNAL_H__ +#define __RPMSG_INTERNAL_H__ + +#include +#include + +#define to_rpmsg_device(d) container_of(d, struct rpmsg_device, dev) +#define to_rpmsg_driver(d) container_of_const(d, struct rpmsg_driver, drv) + +extern const struct class rpmsg_class; + +/** + * struct rpmsg_device_ops - indirection table for the rpmsg_device operations + * @create_channel: create backend-specific channel, optional + * @release_channel: release backend-specific channel, optional + * @create_ept: create backend-specific endpoint, required + * @announce_create: announce presence of new channel, optional + * @announce_destroy: announce destruction of channel, optional + * + * Indirection table for the operations that a rpmsg backend should implement. + * @announce_create and @announce_destroy are optional as the backend might + * advertise new channels implicitly by creating the endpoints. + */ +struct rpmsg_device_ops { + struct rpmsg_device *(*create_channel)(struct rpmsg_device *rpdev, + struct rpmsg_channel_info *chinfo); + int (*release_channel)(struct rpmsg_device *rpdev, + struct rpmsg_channel_info *chinfo); + struct rpmsg_endpoint *(*create_ept)(struct rpmsg_device *rpdev, + rpmsg_rx_cb_t cb, void *priv, + struct rpmsg_channel_info chinfo); + + int (*announce_create)(struct rpmsg_device *rpdev); + int (*announce_destroy)(struct rpmsg_device *rpdev); +}; + +/** + * struct rpmsg_endpoint_ops - indirection table for rpmsg_endpoint operations + * @destroy_ept: see @rpmsg_destroy_ept(), required + * @send: see @rpmsg_send(), required + * @sendto: see @rpmsg_sendto(), optional + * @trysend: see @rpmsg_trysend(), required + * @trysendto: see @rpmsg_trysendto(), optional + * @poll: see @rpmsg_poll(), optional + * @set_flow_control: see @rpmsg_set_flow_control(), optional + * @get_mtu: see @rpmsg_get_mtu(), optional + * + * Indirection table for the operations that a rpmsg backend should implement. + * In addition to @destroy_ept, the backend must at least implement @send and + * @trysend, while the variants sending data off-channel are optional. + */ +struct rpmsg_endpoint_ops { + void (*destroy_ept)(struct rpmsg_endpoint *ept); + + int (*send)(struct rpmsg_endpoint *ept, const void *data, int len); + int (*sendto)(struct rpmsg_endpoint *ept, const void *data, int len, u32 dst); + + int (*trysend)(struct rpmsg_endpoint *ept, const void *data, int len); + int (*trysendto)(struct rpmsg_endpoint *ept, const void *data, int len, u32 dst); + __poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp, + poll_table *wait); + int (*set_flow_control)(struct rpmsg_endpoint *ept, bool pause, u32 dst); + ssize_t (*get_mtu)(struct rpmsg_endpoint *ept); +}; + +struct device *rpmsg_find_device(struct device *parent, + struct rpmsg_channel_info *chinfo); + +struct rpmsg_device *rpmsg_create_channel(struct rpmsg_device *rpdev, + struct rpmsg_channel_info *chinfo); +int rpmsg_release_channel(struct rpmsg_device *rpdev, + struct rpmsg_channel_info *chinfo); +/** + * rpmsg_ctrldev_register_device() - register a char device for control based on rpdev + * @rpdev: prepared rpdev to be used for creating endpoints + * + * This function wraps rpmsg_register_device() preparing the rpdev for use as + * basis for the rpmsg chrdev. + */ +static inline int rpmsg_ctrldev_register_device(struct rpmsg_device *rpdev) +{ + return rpmsg_register_device_override(rpdev, "rpmsg_ctrl"); +} + +#endif -- cgit v1.3.1