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 --- block/bio-integrity-auto.c | 133 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 133 insertions(+) create mode 100644 block/bio-integrity-auto.c (limited to 'block/bio-integrity-auto.c') diff --git a/block/bio-integrity-auto.c b/block/bio-integrity-auto.c new file mode 100644 index 000000000..b1c733ecf --- /dev/null +++ b/block/bio-integrity-auto.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2007, 2008, 2009 Oracle Corporation + * Written by: Martin K. Petersen + * + * Automatically generate and verify integrity data on PI capable devices if the + * bio submitter didn't provide PI itself. This ensures that kernel verifies + * data integrity even if the file system (or other user of the block device) is + * not aware of PI. + */ +#include +#include +#include +#include "blk.h" + +struct bio_integrity_data { + struct bio *bio; + struct bvec_iter saved_bio_iter; + struct work_struct work; + struct bio_integrity_payload bip; + struct bio_vec bvec; +}; + +static struct kmem_cache *bid_slab; +static mempool_t bid_pool; +static struct workqueue_struct *kintegrityd_wq; + +static void bio_integrity_finish(struct bio_integrity_data *bid) +{ + bid->bio->bi_integrity = NULL; + bid->bio->bi_opf &= ~REQ_INTEGRITY; + bio_integrity_free_buf(&bid->bip); + mempool_free(bid, &bid_pool); +} + +static void bio_integrity_verify_fn(struct work_struct *work) +{ + struct bio_integrity_data *bid = + container_of(work, struct bio_integrity_data, work); + struct bio *bio = bid->bio; + + bio->bi_status = bio_integrity_verify(bio, &bid->saved_bio_iter); + bio_integrity_finish(bid); + bio_endio(bio); +} + +#define BIP_CHECK_FLAGS (BIP_CHECK_GUARD | BIP_CHECK_REFTAG | BIP_CHECK_APPTAG) +static bool bip_should_check(struct bio_integrity_payload *bip) +{ + return bip->bip_flags & BIP_CHECK_FLAGS; +} + +/** + * __bio_integrity_endio - Integrity I/O completion function + * @bio: Protected bio + * + * Normally I/O completion is done in interrupt context. However, verifying I/O + * integrity is a time-consuming task which must be run in process context. + * + * This function postpones completion accordingly. + */ +bool __bio_integrity_endio(struct bio *bio) +{ + struct bio_integrity_payload *bip = bio_integrity(bio); + struct bio_integrity_data *bid = + container_of(bip, struct bio_integrity_data, bip); + + if (bio_op(bio) == REQ_OP_READ && !bio->bi_status && + bip_should_check(bip)) { + INIT_WORK(&bid->work, bio_integrity_verify_fn); + queue_work(kintegrityd_wq, &bid->work); + return false; + } + + bio_integrity_finish(bid); + return true; +} + +/** + * bio_integrity_prep - Prepare bio for integrity I/O + * @bio: bio to prepare + * @action: preparation action needed (BI_ACT_*) + * + * Allocate the integrity payload. For writes, generate the integrity metadata + * and for reads, setup the completion handler to verify the metadata. + * + * This is used for bios that do not have user integrity payloads attached. + */ +void bio_integrity_prep(struct bio *bio, unsigned int action) +{ + struct bio_integrity_data *bid; + + bid = mempool_alloc(&bid_pool, GFP_NOIO); + bio_integrity_init(bio, &bid->bip, &bid->bvec, 1); + bid->bio = bio; + bid->bip.bip_flags |= BIP_BLOCK_INTEGRITY; + bio_integrity_alloc_buf(bio, GFP_NOIO, action & BI_ACT_ZERO); + if (action & BI_ACT_CHECK) + bio_integrity_setup_default(bio); + + /* Auto-generate integrity metadata if this is a write */ + if (bio_data_dir(bio) == WRITE && bip_should_check(&bid->bip)) + bio_integrity_generate(bio); + else + bid->saved_bio_iter = bio->bi_iter; +} +EXPORT_SYMBOL(bio_integrity_prep); + +void blk_flush_integrity(void) +{ + flush_workqueue(kintegrityd_wq); +} + +static int __init blk_integrity_auto_init(void) +{ + bid_slab = kmem_cache_create("bio_integrity_data", + sizeof(struct bio_integrity_data), 0, + SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); + + if (mempool_init_slab_pool(&bid_pool, BIO_POOL_SIZE, bid_slab)) + panic("bio: can't create integrity pool\n"); + + /* + * kintegrityd won't block much but may burn a lot of CPU cycles. + * Make it highpri CPU intensive wq with max concurrency of 1. + */ + kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM | + WQ_HIGHPRI | WQ_CPU_INTENSIVE | WQ_PERCPU, 1); + if (!kintegrityd_wq) + panic("Failed to create kintegrityd\n"); + return 0; +} +subsys_initcall(blk_integrity_auto_init); -- cgit v1.3.1