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/aes-xts.h | 94 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 include/crypto/aes-xts.h (limited to 'include/crypto/aes-xts.h') diff --git a/include/crypto/aes-xts.h b/include/crypto/aes-xts.h new file mode 100644 index 000000000..b9e828265 --- /dev/null +++ b/include/crypto/aes-xts.h @@ -0,0 +1,94 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * AES-XTS unauthenticated encryption and decryption + * + * Copyright 2026 Google LLC + */ +#ifndef _CRYPTO_AES_XTS_H +#define _CRYPTO_AES_XTS_H + +#include +#include + +/** + * struct aes_xts_key - A key prepared for AES-XTS encryption and decryption + * + * Note that (depending on the architecture) this typically is around 768 bytes, + * which makes it a bit too large to allocate on the stack in most cases. + */ +struct aes_xts_key { + /* private: */ + struct aes_key main_key; + struct aes_enckey tweak_key; +}; + +/** + * aes_xts_preparekey() - Prepare a key for AES-XTS encryption and decryption + * @key: (output) The key structure to initialize + * @in_key: The raw AES-XTS key + * @key_len: Length of the raw key in bytes + * @flags: Optional flag XTS_FORBID_WEAK_KEYS to forbid keys whose two halves + * are the same. + * + * Users should use memzero_explicit() to zeroize the key struct at the end of + * its lifetime. (But if this function fails, zeroization is unnecessary.) + * + * Context: Any context. + * Return: + * * 0 on success + * * -EINVAL if the key is rejected because its length isn't 32, 64, or (when + * FIPS mode isn't enabled) 48; or because its two halves are the same and + * either XTS_FORBID_WEAK_KEYS is given or FIPS mode is enabled. + */ +int __must_check aes_xts_preparekey(struct aes_xts_key *key, const u8 *in_key, + size_t key_len, int flags); + +/** + * aes_xts_encrypt() - Encrypt data using AES-XTS + * @dst: The destination buffer. Can be in-place or out-of-place. For other + * overlaps the behavior is unspecified. + * @src: The source data + * @len: Number of bytes to encrypt. On non-final calls it must be a nonzero + * multiple of AES_BLOCK_SIZE. On the final call it can be any value >= + * AES_BLOCK_SIZE, i.e. ciphertext stealing is supported. + * @tweak: The tweak. It is updated with the next value, unless @len isn't a + * multiple of AES_BLOCK_SIZE in which case the value is unspecified. + * @key: The key, already prepared using aes_xts_preparekey() + * @cont: %false to begin encrypting a new message (do the tweak encryption); + * %true to continue encrypting a message (skip tweak encryption) + * + * This supports both one-shot and incremental encryption. On the first call, + * pass @cont = %false. On any later calls, pass @cont = %true and the updated + * @tweak; all earlier @len must have been multiples of AES_BLOCK_SIZE. + * + * Context: Any context. + */ +void aes_xts_encrypt(u8 *dst, const u8 *src, size_t len, + u8 tweak[at_least AES_BLOCK_SIZE], + const struct aes_xts_key *key, bool cont); + +/** + * aes_xts_decrypt() - Decrypt data using AES-XTS + * @dst: The destination buffer. Can be in-place or out-of-place. For other + * overlaps the behavior is unspecified. + * @src: The source data + * @len: Number of bytes to decrypt. On non-final calls it must be a nonzero + * multiple of AES_BLOCK_SIZE. On the final call it can be any value >= + * AES_BLOCK_SIZE, i.e. ciphertext stealing is supported. + * @tweak: The tweak. It is updated with the next value, unless @len isn't a + * multiple of AES_BLOCK_SIZE in which case the value is unspecified. + * @key: The key, already prepared using aes_xts_preparekey() + * @cont: %false to begin decrypting a new message (do the tweak encryption); + * %true to continue decrypting a message (skip tweak encryption) + * + * This supports both one-shot and incremental decryption. On the first call, + * pass @cont = %false. On any later calls, pass @cont = %true and the updated + * @tweak; all earlier @len must have been multiples of AES_BLOCK_SIZE. + * + * Context: Any context. + */ +void aes_xts_decrypt(u8 *dst, const u8 *src, size_t len, + u8 tweak[at_least AES_BLOCK_SIZE], + const struct aes_xts_key *key, bool cont); + +#endif /* _CRYPTO_AES_XTS_H */ -- cgit v1.3.1