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 --- fs/unicode/utf8n.h | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) create mode 100644 fs/unicode/utf8n.h (limited to 'fs/unicode/utf8n.h') diff --git a/fs/unicode/utf8n.h b/fs/unicode/utf8n.h new file mode 100644 index 000000000..fc703aa4b --- /dev/null +++ b/fs/unicode/utf8n.h @@ -0,0 +1,83 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2014 SGI. + * All rights reserved. + */ + +#ifndef UTF8NORM_H +#define UTF8NORM_H + +#include +#include +#include +#include +#include + +int utf8version_is_supported(const struct unicode_map *um, unsigned int version); + +/* + * Determine the length of the normalized from of the string, + * excluding any terminating NULL byte. + * Returns 0 if only ignorable code points are present. + * Returns -1 if the input is not valid UTF-8. + */ +ssize_t utf8nlen(const struct unicode_map *um, enum utf8_normalization n, + const char *s, size_t len); + +/* Needed in struct utf8cursor below. */ +#define UTF8HANGULLEAF (12) + +/* + * Cursor structure used by the normalizer. + */ +struct utf8cursor { + const struct unicode_map *um; + enum utf8_normalization n; + const char *s; + const char *p; + const char *ss; + const char *sp; + unsigned int len; + unsigned int slen; + short int ccc; + short int nccc; + unsigned char hangul[UTF8HANGULLEAF]; +}; + +/* + * Initialize a utf8cursor to normalize a string. + * Returns 0 on success. + * Returns -1 on failure. + */ +int utf8ncursor(struct utf8cursor *u8c, const struct unicode_map *um, + enum utf8_normalization n, const char *s, size_t len); + +/* + * Get the next byte in the normalization. + * Returns a value > 0 && < 256 on success. + * Returns 0 when the end of the normalization is reached. + * Returns -1 if the string being normalized is not valid UTF-8. + */ +extern int utf8byte(struct utf8cursor *u8c); + +struct utf8data { + unsigned int maxage; + unsigned int offset; +}; + +struct utf8data_table { + const unsigned int *utf8agetab; + int utf8agetab_size; + + const struct utf8data *utf8nfdicfdata; + int utf8nfdicfdata_size; + + const struct utf8data *utf8nfdidata; + int utf8nfdidata_size; + + const unsigned char *utf8data; +}; + +extern const struct utf8data_table utf8_data_table; + +#endif /* UTF8NORM_H */ -- cgit v1.3.1