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/coda/psdev.c | 438 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 438 insertions(+) create mode 100644 fs/coda/psdev.c (limited to 'fs/coda/psdev.c') diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c new file mode 100644 index 000000000..3c3148588 --- /dev/null +++ b/fs/coda/psdev.c @@ -0,0 +1,438 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * An implementation of a loadable kernel mode driver providing + * multiple kernel/user space bidirectional communications links. + * + * Author: Alan Cox + * + * Adapted to become the Linux 2.0 Coda pseudo device + * Peter Braam + * Michael Callahan + * + * Changes for Linux 2.1 + * Copyright (c) 1997 Carnegie-Mellon University + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include "coda_psdev.h" +#include "coda_linux.h" + +#include "coda_int.h" + +/* statistics */ +int coda_hard; /* allows signals during upcalls */ +unsigned long coda_timeout = 30; /* .. secs, then signals will dequeue */ + + +struct venus_comm coda_comms[MAX_CODADEVS]; +static struct class *coda_psdev_class; + +/* + * Device operations + */ + +static __poll_t coda_psdev_poll(struct file *file, poll_table * wait) +{ + struct venus_comm *vcp = (struct venus_comm *) file->private_data; + __poll_t mask = EPOLLOUT | EPOLLWRNORM; + + poll_wait(file, &vcp->vc_waitq, wait); + mutex_lock(&vcp->vc_mutex); + if (!list_empty(&vcp->vc_pending)) + mask |= EPOLLIN | EPOLLRDNORM; + mutex_unlock(&vcp->vc_mutex); + + return mask; +} + +static long coda_psdev_ioctl(struct file * filp, unsigned int cmd, unsigned long arg) +{ + unsigned int data; + + switch(cmd) { + case CIOC_KERNEL_VERSION: + data = CODA_KERNEL_VERSION; + return put_user(data, (int __user *) arg); + default: + return -ENOTTY; + } + + return 0; +} + +/* + * Receive a message written by Venus to the psdev + */ + +static ssize_t coda_psdev_write(struct file *file, const char __user *buf, + size_t nbytes, loff_t *off) +{ + struct venus_comm *vcp = (struct venus_comm *) file->private_data; + struct upc_req *req = NULL; + struct upc_req *tmp; + struct list_head *lh; + struct coda_in_hdr hdr; + ssize_t retval = 0, count = 0; + int error; + + /* make sure there is enough to copy out the (opcode, unique) values */ + if (nbytes < (2 * sizeof(u_int32_t))) + return -EINVAL; + + /* Peek at the opcode, uniquefier */ + if (copy_from_user(&hdr, buf, 2 * sizeof(u_int32_t))) + return -EFAULT; + + if (DOWNCALL(hdr.opcode)) { + union outputArgs *dcbuf; + int size = sizeof(*dcbuf); + + if ( nbytes < sizeof(struct coda_out_hdr) ) { + pr_warn("coda_downcall opc %d uniq %d, not enough!\n", + hdr.opcode, hdr.unique); + count = nbytes; + goto out; + } + if ( nbytes > size ) { + pr_warn("downcall opc %d, uniq %d, too much!", + hdr.opcode, hdr.unique); + nbytes = size; + } + + dcbuf = vmemdup_user(buf, nbytes); + if (IS_ERR(dcbuf)) { + retval = PTR_ERR(dcbuf); + goto out; + } + + /* what downcall errors does Venus handle ? */ + error = coda_downcall(vcp, hdr.opcode, dcbuf, nbytes); + + kvfree(dcbuf); + if (error) { + pr_warn("%s: coda_downcall error: %d\n", + __func__, error); + retval = error; + goto out; + } + count = nbytes; + goto out; + } + + /* Look for the message on the processing queue. */ + mutex_lock(&vcp->vc_mutex); + list_for_each(lh, &vcp->vc_processing) { + tmp = list_entry(lh, struct upc_req , uc_chain); + if (tmp->uc_unique == hdr.unique) { + req = tmp; + list_del(&req->uc_chain); + break; + } + } + mutex_unlock(&vcp->vc_mutex); + + if (!req) { + pr_warn("%s: msg (%d, %d) not found\n", + __func__, hdr.opcode, hdr.unique); + retval = -ESRCH; + goto out; + } + + /* move data into response buffer. */ + if (req->uc_outSize < nbytes) { + pr_warn("%s: too much cnt: %d, cnt: %ld, opc: %d, uniq: %d.\n", + __func__, req->uc_outSize, (long)nbytes, + hdr.opcode, hdr.unique); + nbytes = req->uc_outSize; /* don't have more space! */ + } + if (copy_from_user(req->uc_data, buf, nbytes)) { + req->uc_flags |= CODA_REQ_ABORT; + wake_up(&req->uc_sleep); + retval = -EFAULT; + goto out; + } + + /* adjust outsize. is this useful ?? */ + req->uc_outSize = nbytes; + req->uc_flags |= CODA_REQ_WRITE; + count = nbytes; + + /* Convert filedescriptor into a file handle */ + if (req->uc_opcode == CODA_OPEN_BY_FD) { + struct coda_open_by_fd_out *outp = + (struct coda_open_by_fd_out *)req->uc_data; + if (!outp->oh.result) { + outp->fh = fget(outp->fd); + if (!outp->fh) + return -EBADF; + } + } + + wake_up(&req->uc_sleep); +out: + return(count ? count : retval); +} + +/* + * Read a message from the kernel to Venus + */ + +static ssize_t coda_psdev_read(struct file * file, char __user * buf, + size_t nbytes, loff_t *off) +{ + DECLARE_WAITQUEUE(wait, current); + struct venus_comm *vcp = (struct venus_comm *) file->private_data; + struct upc_req *req; + ssize_t retval = 0, count = 0; + + if (nbytes == 0) + return 0; + + mutex_lock(&vcp->vc_mutex); + + add_wait_queue(&vcp->vc_waitq, &wait); + set_current_state(TASK_INTERRUPTIBLE); + + while (list_empty(&vcp->vc_pending)) { + if (file->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + break; + } + if (signal_pending(current)) { + retval = -ERESTARTSYS; + break; + } + mutex_unlock(&vcp->vc_mutex); + schedule(); + mutex_lock(&vcp->vc_mutex); + } + + set_current_state(TASK_RUNNING); + remove_wait_queue(&vcp->vc_waitq, &wait); + + if (retval) + goto out; + + req = list_entry(vcp->vc_pending.next, struct upc_req,uc_chain); + list_del(&req->uc_chain); + + /* Move the input args into userspace */ + count = req->uc_inSize; + if (nbytes < req->uc_inSize) { + pr_warn("%s: Venus read %ld bytes of %d in message\n", + __func__, (long)nbytes, req->uc_inSize); + count = nbytes; + } + + if (copy_to_user(buf, req->uc_data, count)) + retval = -EFAULT; + + /* If request was not a signal, enqueue and don't free */ + if (!(req->uc_flags & CODA_REQ_ASYNC)) { + req->uc_flags |= CODA_REQ_READ; + list_add_tail(&(req->uc_chain), &vcp->vc_processing); + goto out; + } + + kvfree(req->uc_data); + kfree(req); +out: + mutex_unlock(&vcp->vc_mutex); + return (count ? count : retval); +} + +static int coda_psdev_open(struct inode * inode, struct file * file) +{ + struct venus_comm *vcp; + int idx, err; + + if (task_active_pid_ns(current) != &init_pid_ns) + return -EINVAL; + + if (current_user_ns() != &init_user_ns) + return -EINVAL; + + idx = iminor(inode); + if (idx < 0 || idx >= MAX_CODADEVS) + return -ENODEV; + + err = -EBUSY; + vcp = &coda_comms[idx]; + mutex_lock(&vcp->vc_mutex); + + if (!vcp->vc_inuse) { + vcp->vc_inuse++; + + INIT_LIST_HEAD(&vcp->vc_pending); + INIT_LIST_HEAD(&vcp->vc_processing); + init_waitqueue_head(&vcp->vc_waitq); + vcp->vc_sb = NULL; + vcp->vc_seq = 0; + + file->private_data = vcp; + err = 0; + } + + mutex_unlock(&vcp->vc_mutex); + return err; +} + + +static int coda_psdev_release(struct inode * inode, struct file * file) +{ + struct venus_comm *vcp = (struct venus_comm *) file->private_data; + struct upc_req *req, *tmp; + + if (!vcp || !vcp->vc_inuse ) { + pr_warn("%s: Not open.\n", __func__); + return -1; + } + + mutex_lock(&vcp->vc_mutex); + + /* Wakeup clients so they can return. */ + list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) { + list_del(&req->uc_chain); + + /* Async requests need to be freed here */ + if (req->uc_flags & CODA_REQ_ASYNC) { + kvfree(req->uc_data); + kfree(req); + continue; + } + req->uc_flags |= CODA_REQ_ABORT; + wake_up(&req->uc_sleep); + } + + list_for_each_entry_safe(req, tmp, &vcp->vc_processing, uc_chain) { + list_del(&req->uc_chain); + + req->uc_flags |= CODA_REQ_ABORT; + wake_up(&req->uc_sleep); + } + + file->private_data = NULL; + vcp->vc_inuse--; + mutex_unlock(&vcp->vc_mutex); + return 0; +} + + +static const struct file_operations coda_psdev_fops = { + .owner = THIS_MODULE, + .read = coda_psdev_read, + .write = coda_psdev_write, + .poll = coda_psdev_poll, + .unlocked_ioctl = coda_psdev_ioctl, + .open = coda_psdev_open, + .release = coda_psdev_release, + .llseek = noop_llseek, +}; + +static int __init init_coda_psdev(void) +{ + int i, err = 0; + if (register_chrdev(CODA_PSDEV_MAJOR, "coda", &coda_psdev_fops)) { + pr_err("%s: unable to get major %d\n", + __func__, CODA_PSDEV_MAJOR); + return -EIO; + } + coda_psdev_class = class_create("coda"); + if (IS_ERR(coda_psdev_class)) { + err = PTR_ERR(coda_psdev_class); + goto out_chrdev; + } + for (i = 0; i < MAX_CODADEVS; i++) { + mutex_init(&(&coda_comms[i])->vc_mutex); + device_create(coda_psdev_class, NULL, + MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i); + } + coda_sysctl_init(); + goto out; + +out_chrdev: + unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); +out: + return err; +} + +MODULE_AUTHOR("Jan Harkes, Peter J. Braam"); +MODULE_DESCRIPTION("Coda Distributed File System VFS interface"); +MODULE_ALIAS_CHARDEV_MAJOR(CODA_PSDEV_MAJOR); +MODULE_LICENSE("GPL"); +MODULE_VERSION("7.2"); + +static int __init init_coda(void) +{ + int status; + int i; + + status = coda_init_inodecache(); + if (status) + goto out2; + status = init_coda_psdev(); + if ( status ) { + pr_warn("Problem (%d) in init_coda_psdev\n", status); + goto out1; + } + + status = register_filesystem(&coda_fs_type); + if (status) { + pr_warn("failed to register filesystem!\n"); + goto out; + } + return 0; +out: + for (i = 0; i < MAX_CODADEVS; i++) + device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); + class_destroy(coda_psdev_class); + unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); + coda_sysctl_clean(); +out1: + coda_destroy_inodecache(); +out2: + return status; +} + +static void __exit exit_coda(void) +{ + int err, i; + + err = unregister_filesystem(&coda_fs_type); + if (err != 0) + pr_warn("failed to unregister filesystem\n"); + for (i = 0; i < MAX_CODADEVS; i++) + device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i)); + class_destroy(coda_psdev_class); + unregister_chrdev(CODA_PSDEV_MAJOR, "coda"); + coda_sysctl_clean(); + coda_destroy_inodecache(); +} + +module_init(init_coda); +module_exit(exit_coda); + -- cgit v1.3.1