kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

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 <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/fs/ntfs/ea.h b/fs/ntfs/ea.h
new file mode 100644
index 000000000..1f63bd55e
--- /dev/null
+++ b/fs/ntfs/ea.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _LINUX_NTFS_EA_H
+#define _LINUX_NTFS_EA_H
+
+#define NTFS_EA_UID	BIT(1)
+#define NTFS_EA_GID	BIT(2)
+#define NTFS_EA_MODE	BIT(3)
+
+extern const struct xattr_handler *const ntfs_xattr_handlers[];
+
+int ntfs_ea_set_wsl_not_symlink(struct ntfs_inode *ni, mode_t mode, dev_t dev);
+int ntfs_ea_get_wsl_inode(struct inode *inode, dev_t *rdevp, unsigned int flags);
+int ntfs_ea_set_wsl_inode(struct inode *inode, dev_t rdev, __le16 *ea_size,
+		unsigned int flags);
+ssize_t ntfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
+
+#ifdef CONFIG_NTFS_FS_POSIX_ACL
+struct posix_acl *ntfs_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+			       int type);
+int ntfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		 struct posix_acl *acl, int type);
+int ntfs_init_acl(struct mnt_idmap *idmap, struct inode *inode,
+		  struct inode *dir);
+#else
+#define ntfs_get_acl NULL
+#define ntfs_set_acl NULL
+#endif
+
+#endif /* _LINUX_NTFS_EA_H */