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/minix/dir.c | 458 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 458 insertions(+) create mode 100644 fs/minix/dir.c (limited to 'fs/minix/dir.c') diff --git a/fs/minix/dir.c b/fs/minix/dir.c new file mode 100644 index 000000000..2ca16f849 --- /dev/null +++ b/fs/minix/dir.c @@ -0,0 +1,458 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/minix/dir.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * minix directory handling functions + * + * Updated to filesystem version 3 by Daniel Aragones + */ + +#include "minix.h" +#include +#include +#include + +typedef struct minix_dir_entry minix_dirent; +typedef struct minix3_dir_entry minix3_dirent; + +static int minix_readdir(struct file *, struct dir_context *); + +const struct file_operations minix_dir_operations = { + .llseek = generic_file_llseek, + .read = generic_read_dir, + .iterate_shared = minix_readdir, + .fsync = simple_fsync, +}; + +/* + * Return the offset into page `page_nr' of the last valid + * byte in that page, plus one. + */ +static unsigned +minix_last_byte(struct inode *inode, unsigned long page_nr) +{ + unsigned last_byte = PAGE_SIZE; + + if (page_nr == (inode->i_size >> PAGE_SHIFT)) + last_byte = inode->i_size & (PAGE_SIZE - 1); + return last_byte; +} + +static void dir_commit_chunk(struct folio *folio, loff_t pos, unsigned len) +{ + struct address_space *mapping = folio->mapping; + struct inode *dir = mapping->host; + + block_write_end(pos, len, len, folio); + + if (pos+len > dir->i_size) { + i_size_write(dir, pos+len); + mark_inode_dirty(dir); + } + folio_unlock(folio); +} + +static int minix_handle_dirsync(struct inode *dir) +{ + int err; + + err = filemap_write_and_wait(dir->i_mapping); + if (!err) + err = sync_inode_metadata(dir, 1); + return err; +} + +static void *dir_get_folio(struct inode *dir, unsigned long n, + struct folio **foliop) +{ + struct folio *folio = read_mapping_folio(dir->i_mapping, n, NULL); + + if (IS_ERR(folio)) + return ERR_CAST(folio); + *foliop = folio; + return kmap_local_folio(folio, 0); +} + +static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi) +{ + return (void*)((char*)de + sbi->s_dirsize); +} + +static int minix_readdir(struct file *file, struct dir_context *ctx) +{ + struct inode *inode = file_inode(file); + struct super_block *sb = inode->i_sb; + struct minix_sb_info *sbi = minix_sb(sb); + unsigned chunk_size = sbi->s_dirsize; + unsigned long npages = dir_pages(inode); + unsigned long pos = ctx->pos; + unsigned offset; + unsigned long n; + + ctx->pos = pos = ALIGN(pos, chunk_size); + if (pos >= inode->i_size) + return 0; + + offset = pos & ~PAGE_MASK; + n = pos >> PAGE_SHIFT; + + for ( ; n < npages; n++, offset = 0) { + char *p, *kaddr, *limit; + struct folio *folio; + + kaddr = dir_get_folio(inode, n, &folio); + if (IS_ERR(kaddr)) + continue; + p = kaddr+offset; + limit = kaddr + minix_last_byte(inode, n) - chunk_size; + for ( ; p <= limit; p = minix_next_entry(p, sbi)) { + const char *name; + __u32 inumber; + if (sbi->s_version == MINIX_V3) { + minix3_dirent *de3 = (minix3_dirent *)p; + name = de3->name; + inumber = de3->inode; + } else { + minix_dirent *de = (minix_dirent *)p; + name = de->name; + inumber = de->inode; + } + if (inumber) { + unsigned l = strnlen(name, sbi->s_namelen); + if (!dir_emit(ctx, name, l, + inumber, DT_UNKNOWN)) { + folio_release_kmap(folio, p); + return 0; + } + } + ctx->pos += chunk_size; + } + folio_release_kmap(folio, kaddr); + } + return 0; +} + +static inline int namecompare(int len, int maxlen, + const char * name, const char * buffer) +{ + if (len < maxlen && buffer[len]) + return 0; + return !memcmp(name, buffer, len); +} + +/* + * minix_find_entry() + * + * finds an entry in the specified directory with the wanted name. + * It does NOT read the inode of the + * entry - you'll have to do that yourself if you want to. + * + * On Success folio_release_kmap() should be called on *foliop. + */ +minix_dirent *minix_find_entry(struct dentry *dentry, struct folio **foliop) +{ + const char * name = dentry->d_name.name; + int namelen = dentry->d_name.len; + struct inode * dir = d_inode(dentry->d_parent); + struct super_block * sb = dir->i_sb; + struct minix_sb_info * sbi = minix_sb(sb); + unsigned long n; + unsigned long npages = dir_pages(dir); + char *p; + + char *namx; + __u32 inumber; + + for (n = 0; n < npages; n++) { + char *kaddr, *limit; + + kaddr = dir_get_folio(dir, n, foliop); + if (IS_ERR(kaddr)) + continue; + + limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize; + for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) { + if (sbi->s_version == MINIX_V3) { + minix3_dirent *de3 = (minix3_dirent *)p; + namx = de3->name; + inumber = de3->inode; + } else { + minix_dirent *de = (minix_dirent *)p; + namx = de->name; + inumber = de->inode; + } + if (!inumber) + continue; + if (namecompare(namelen, sbi->s_namelen, name, namx)) + goto found; + } + folio_release_kmap(*foliop, kaddr); + } + return NULL; + +found: + return (minix_dirent *)p; +} + +int minix_add_link(struct dentry *dentry, struct inode *inode) +{ + struct inode *dir = d_inode(dentry->d_parent); + const char * name = dentry->d_name.name; + int namelen = dentry->d_name.len; + struct super_block * sb = dir->i_sb; + struct minix_sb_info * sbi = minix_sb(sb); + struct folio *folio = NULL; + unsigned long npages = dir_pages(dir); + unsigned long n; + char *kaddr, *p; + minix_dirent *de; + minix3_dirent *de3; + loff_t pos; + int err; + char *namx = NULL; + __u32 inumber; + + /* + * We take care of directory expansion in the same loop + * This code plays outside i_size, so it locks the page + * to protect that region. + */ + for (n = 0; n <= npages; n++) { + char *limit, *dir_end; + + kaddr = dir_get_folio(dir, n, &folio); + if (IS_ERR(kaddr)) + return PTR_ERR(kaddr); + folio_lock(folio); + dir_end = kaddr + minix_last_byte(dir, n); + limit = kaddr + PAGE_SIZE - sbi->s_dirsize; + for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) { + de = (minix_dirent *)p; + de3 = (minix3_dirent *)p; + if (sbi->s_version == MINIX_V3) { + namx = de3->name; + inumber = de3->inode; + } else { + namx = de->name; + inumber = de->inode; + } + if (p == dir_end) { + /* We hit i_size */ + if (sbi->s_version == MINIX_V3) + de3->inode = 0; + else + de->inode = 0; + goto got_it; + } + if (!inumber) + goto got_it; + err = -EEXIST; + if (namecompare(namelen, sbi->s_namelen, name, namx)) + goto out_unlock; + } + folio_unlock(folio); + folio_release_kmap(folio, kaddr); + } + BUG(); + return -EINVAL; + +got_it: + pos = folio_pos(folio) + offset_in_folio(folio, p); + err = minix_prepare_chunk(folio, pos, sbi->s_dirsize); + if (err) + goto out_unlock; + memcpy (namx, name, namelen); + if (sbi->s_version == MINIX_V3) { + memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4); + de3->inode = inode->i_ino; + } else { + memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2); + de->inode = inode->i_ino; + } + dir_commit_chunk(folio, pos, sbi->s_dirsize); + inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); + mark_inode_dirty(dir); + err = minix_handle_dirsync(dir); +out_put: + folio_release_kmap(folio, kaddr); + return err; +out_unlock: + folio_unlock(folio); + goto out_put; +} + +int minix_delete_entry(struct minix_dir_entry *de, struct folio *folio) +{ + struct inode *inode = folio->mapping->host; + loff_t pos = folio_pos(folio) + offset_in_folio(folio, de); + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + unsigned len = sbi->s_dirsize; + int err; + + folio_lock(folio); + err = minix_prepare_chunk(folio, pos, len); + if (err) { + folio_unlock(folio); + return err; + } + if (sbi->s_version == MINIX_V3) + ((minix3_dirent *)de)->inode = 0; + else + de->inode = 0; + dir_commit_chunk(folio, pos, len); + inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode)); + mark_inode_dirty(inode); + return minix_handle_dirsync(inode); +} + +int minix_make_empty(struct inode *inode, struct inode *dir) +{ + struct folio *folio = filemap_grab_folio(inode->i_mapping, 0); + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + char *kaddr; + int err; + + if (IS_ERR(folio)) + return PTR_ERR(folio); + err = minix_prepare_chunk(folio, 0, 2 * sbi->s_dirsize); + if (err) { + folio_unlock(folio); + goto fail; + } + + kaddr = kmap_local_folio(folio, 0); + memset(kaddr, 0, folio_size(folio)); + + if (sbi->s_version == MINIX_V3) { + minix3_dirent *de3 = (minix3_dirent *)kaddr; + + de3->inode = inode->i_ino; + strcpy(de3->name, "."); + de3 = minix_next_entry(de3, sbi); + de3->inode = dir->i_ino; + strcpy(de3->name, ".."); + } else { + minix_dirent *de = (minix_dirent *)kaddr; + + de->inode = inode->i_ino; + strcpy(de->name, "."); + de = minix_next_entry(de, sbi); + de->inode = dir->i_ino; + strcpy(de->name, ".."); + } + kunmap_local(kaddr); + + dir_commit_chunk(folio, 0, 2 * sbi->s_dirsize); + err = minix_handle_dirsync(inode); +fail: + folio_put(folio); + return err; +} + +/* + * routine to check that the specified directory is empty (for rmdir) + */ +int minix_empty_dir(struct inode * inode) +{ + struct folio *folio = NULL; + unsigned long i, npages = dir_pages(inode); + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + char *name, *kaddr; + __u32 inumber; + + for (i = 0; i < npages; i++) { + char *p, *limit; + + kaddr = dir_get_folio(inode, i, &folio); + if (IS_ERR(kaddr)) + continue; + + limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize; + for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) { + if (sbi->s_version == MINIX_V3) { + minix3_dirent *de3 = (minix3_dirent *)p; + name = de3->name; + inumber = de3->inode; + } else { + minix_dirent *de = (minix_dirent *)p; + name = de->name; + inumber = de->inode; + } + + if (inumber != 0) { + /* check for . and .. */ + if (name[0] != '.') + goto not_empty; + if (!name[1]) { + if (inumber != inode->i_ino) + goto not_empty; + } else if (name[1] != '.') + goto not_empty; + else if (name[2]) + goto not_empty; + } + } + folio_release_kmap(folio, kaddr); + } + return 1; + +not_empty: + folio_release_kmap(folio, kaddr); + return 0; +} + +/* Releases the page */ +int minix_set_link(struct minix_dir_entry *de, struct folio *folio, + struct inode *inode) +{ + struct inode *dir = folio->mapping->host; + struct minix_sb_info *sbi = minix_sb(dir->i_sb); + loff_t pos = folio_pos(folio) + offset_in_folio(folio, de); + int err; + + folio_lock(folio); + err = minix_prepare_chunk(folio, pos, sbi->s_dirsize); + if (err) { + folio_unlock(folio); + return err; + } + if (sbi->s_version == MINIX_V3) + ((minix3_dirent *)de)->inode = inode->i_ino; + else + de->inode = inode->i_ino; + dir_commit_chunk(folio, pos, sbi->s_dirsize); + inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); + mark_inode_dirty(dir); + return minix_handle_dirsync(dir); +} + +struct minix_dir_entry *minix_dotdot(struct inode *dir, struct folio **foliop) +{ + struct minix_sb_info *sbi = minix_sb(dir->i_sb); + struct minix_dir_entry *de = dir_get_folio(dir, 0, foliop); + + if (!IS_ERR(de)) + return minix_next_entry(de, sbi); + return NULL; +} + +ino_t minix_inode_by_name(struct dentry *dentry) +{ + struct folio *folio; + struct minix_dir_entry *de = minix_find_entry(dentry, &folio); + ino_t res = 0; + + if (de) { + struct inode *inode = folio->mapping->host; + struct minix_sb_info *sbi = minix_sb(inode->i_sb); + + if (sbi->s_version == MINIX_V3) + res = ((minix3_dirent *) de)->inode; + else + res = de->inode; + folio_release_kmap(folio, de); + } + return res; +} -- cgit v1.3.1