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/crypto/twofish.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 include/crypto/twofish.h (limited to 'include/crypto/twofish.h') diff --git a/include/crypto/twofish.h b/include/crypto/twofish.h new file mode 100644 index 000000000..f6b307a58 --- /dev/null +++ b/include/crypto/twofish.h @@ -0,0 +1,25 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _CRYPTO_TWOFISH_H +#define _CRYPTO_TWOFISH_H + +#include + +#define TF_MIN_KEY_SIZE 16 +#define TF_MAX_KEY_SIZE 32 +#define TF_BLOCK_SIZE 16 + +struct crypto_tfm; + +/* Structure for an expanded Twofish key. s contains the key-dependent + * S-boxes composed with the MDS matrix; w contains the eight "whitening" + * subkeys, K[0] through K[7]. k holds the remaining, "round" subkeys. Note + * that k[i] corresponds to what the Twofish paper calls K[i+8]. */ +struct twofish_ctx { + u32 s[4][256], w[8], k[32]; +}; + +int __twofish_setkey(struct twofish_ctx *ctx, const u8 *key, + unsigned int key_len); +int twofish_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int key_len); + +#endif -- cgit v1.3.1