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/media/v4l2-isp.h | 91 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 include/media/v4l2-isp.h (limited to 'include/media/v4l2-isp.h') diff --git a/include/media/v4l2-isp.h b/include/media/v4l2-isp.h new file mode 100644 index 000000000..f3a6d0edc --- /dev/null +++ b/include/media/v4l2-isp.h @@ -0,0 +1,91 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Video4Linux2 generic ISP parameters and statistics support + * + * Copyright (C) 2025 Ideas On Board Oy + * Author: Jacopo Mondi + */ + +#ifndef _V4L2_ISP_H_ +#define _V4L2_ISP_H_ + +#include + +struct device; +struct vb2_buffer; + +/** + * v4l2_isp_params_buffer_size - Calculate size of v4l2_isp_params_buffer + * @max_params_size: The total size of the ISP configuration blocks + * + * Users of the v4l2 extensible parameters will have differing sized data arrays + * depending on their specific parameter buffers. Drivers and userspace will + * need to be able to calculate the appropriate size of the struct to + * accommodate all ISP configuration blocks provided by the platform. + * This macro provides a convenient tool for the calculation. + */ +#define v4l2_isp_params_buffer_size(max_params_size) \ + (offsetof(struct v4l2_isp_params_buffer, data) + (max_params_size)) + +/** + * v4l2_isp_params_validate_buffer_size - Validate a V4L2 ISP buffer sizes + * @dev: the driver's device pointer + * @vb: the videobuf2 buffer + * @max_size: the maximum allowed buffer size + * + * This function performs validation of the size of a V4L2 ISP parameters buffer + * before the driver can access the actual data buffer content. + * + * After the sizes validation, drivers should copy the buffer content to a + * kernel-only memory area to prevent userspace from modifying it, + * before completing validation using v4l2_isp_params_validate_buffer(). + * + * The @vb buffer as received from the vb2 .buf_prepare() operation is checked + * against @max_size and it's validated to be large enough to accommodate at + * least one ISP configuration block. + */ +int v4l2_isp_params_validate_buffer_size(struct device *dev, + struct vb2_buffer *vb, + size_t max_size); + +/** + * struct v4l2_isp_params_block_type_info - V4L2 ISP per-block-type info + * @size: the block type expected size + * + * The v4l2_isp_params_block_type_info collects information of the ISP + * configuration block types for validation purposes. It currently only contains + * the expected block type size. + * + * Drivers shall prepare a list of block type info, indexed by block type, one + * for each supported ISP block type and correctly populate them with the + * expected block type size. + */ +struct v4l2_isp_params_block_type_info { + size_t size; +}; + +/** + * v4l2_isp_params_validate_buffer - Validate a V4L2 ISP parameters buffer + * @dev: the driver's device pointer + * @vb: the videobuf2 buffer + * @buffer: the V4L2 ISP parameters buffer + * @type_info: the array of per-block-type validation info + * @num_block_types: the number of block types in the type_info array + * + * This function completes the validation of a V4L2 ISP parameters buffer, + * verifying each configuration block correctness before the driver can use + * them to program the hardware. + * + * Drivers should use this function after having validated the correctness of + * the vb2 buffer sizes by using the v4l2_isp_params_validate_buffer_size() + * helper first. Once the buffer size has been validated, drivers should + * perform a copy of the user provided buffer into a kernel-only memory buffer + * to prevent userspace from modifying its content after it has been submitted + * to the driver, and then call this function to complete validation. + */ +int v4l2_isp_params_validate_buffer(struct device *dev, struct vb2_buffer *vb, + const struct v4l2_isp_params_buffer *buffer, + const struct v4l2_isp_params_block_type_info *type_info, + size_t num_block_types); + +#endif /* _V4L2_ISP_H_ */ -- cgit v1.3.1