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 --- io_uring/filetable.c | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 158 insertions(+) create mode 100644 io_uring/filetable.c (limited to 'io_uring/filetable.c') diff --git a/io_uring/filetable.c b/io_uring/filetable.c new file mode 100644 index 000000000..cb1838c9f --- /dev/null +++ b/io_uring/filetable.c @@ -0,0 +1,158 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "io_uring.h" +#include "rsrc.h" +#include "filetable.h" + +static int io_file_bitmap_get(struct io_ring_ctx *ctx) +{ + struct io_file_table *table = &ctx->file_table; + unsigned long nr = ctx->file_alloc_end; + int ret; + + if (!table->bitmap) + return -ENFILE; + + if (table->alloc_hint < ctx->file_alloc_start || + table->alloc_hint >= ctx->file_alloc_end) + table->alloc_hint = ctx->file_alloc_start; + + do { + ret = find_next_zero_bit(table->bitmap, nr, table->alloc_hint); + if (ret != nr) + return ret; + + if (table->alloc_hint == ctx->file_alloc_start) + break; + nr = table->alloc_hint; + table->alloc_hint = ctx->file_alloc_start; + } while (1); + + return -ENFILE; +} + +bool io_alloc_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table, + unsigned nr_files) +{ + if (io_rsrc_data_alloc(&table->data, nr_files)) + return false; + table->bitmap = bitmap_zalloc(nr_files, GFP_KERNEL_ACCOUNT); + if (table->bitmap) + return true; + io_rsrc_data_free(ctx, &table->data); + return false; +} + +void io_free_file_tables(struct io_ring_ctx *ctx, struct io_file_table *table) +{ + io_rsrc_data_free(ctx, &table->data); + bitmap_free(table->bitmap); + table->bitmap = NULL; +} + +static int io_install_fixed_file(struct io_ring_ctx *ctx, struct file *file, + u32 slot_index) + __must_hold(&ctx->uring_lock) +{ + struct io_rsrc_node *node; + + if (io_is_uring_fops(file)) + return -EBADF; + if (!ctx->file_table.data.nr) + return -ENXIO; + if (slot_index >= ctx->file_table.data.nr) + return -EINVAL; + + node = io_rsrc_node_alloc(ctx, IORING_RSRC_FILE); + if (!node) + return -ENOMEM; + + if (!io_reset_rsrc_node(ctx, &ctx->file_table.data, slot_index)) + io_file_bitmap_set(&ctx->file_table, slot_index); + + ctx->file_table.data.nodes[slot_index] = node; + io_fixed_file_set(node, file); + return 0; +} + +int __io_fixed_fd_install(struct io_ring_ctx *ctx, struct file *file, + unsigned int file_slot) +{ + bool alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC; + int ret; + + if (alloc_slot) { + ret = io_file_bitmap_get(ctx); + if (unlikely(ret < 0)) + return ret; + file_slot = ret; + } else { + file_slot--; + } + + ret = io_install_fixed_file(ctx, file, file_slot); + if (!ret && alloc_slot) + ret = file_slot; + return ret; +} +/* + * Note when io_fixed_fd_install() returns error value, it will ensure + * fput() is called correspondingly. + */ +int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags, + struct file *file, unsigned int file_slot) +{ + struct io_ring_ctx *ctx = req->ctx; + int ret; + + io_ring_submit_lock(ctx, issue_flags); + ret = __io_fixed_fd_install(ctx, file, file_slot); + io_ring_submit_unlock(ctx, issue_flags); + + if (unlikely(ret < 0)) + fput(file); + return ret; +} + +int io_fixed_fd_remove(struct io_ring_ctx *ctx, unsigned int offset) +{ + struct io_rsrc_node *node; + + if (unlikely(!ctx->file_table.data.nr)) + return -ENXIO; + if (offset >= ctx->file_table.data.nr) + return -EINVAL; + + node = io_rsrc_node_lookup(&ctx->file_table.data, offset); + if (!node) + return -EBADF; + io_reset_rsrc_node(ctx, &ctx->file_table.data, offset); + io_file_bitmap_clear(&ctx->file_table, offset); + return 0; +} + +int io_register_file_alloc_range(struct io_ring_ctx *ctx, + struct io_uring_file_index_range __user *arg) +{ + struct io_uring_file_index_range range; + u32 end; + + if (copy_from_user(&range, arg, sizeof(range))) + return -EFAULT; + if (check_add_overflow(range.off, range.len, &end)) + return -EOVERFLOW; + if (range.resv || end > ctx->file_table.data.nr) + return -EINVAL; + + io_file_table_set_alloc_range(ctx, range.off, range.len); + return 0; +} -- cgit v1.3.1