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 --- drivers/accessibility/speakup/devsynth.c | 178 +++++++++++++++++++++++++++++++ 1 file changed, 178 insertions(+) create mode 100644 drivers/accessibility/speakup/devsynth.c (limited to 'drivers/accessibility/speakup/devsynth.c') diff --git a/drivers/accessibility/speakup/devsynth.c b/drivers/accessibility/speakup/devsynth.c new file mode 100644 index 000000000..e3d909bd0 --- /dev/null +++ b/drivers/accessibility/speakup/devsynth.c @@ -0,0 +1,178 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include /* for misc_register, and MISC_DYNAMIC_MINOR */ +#include +#include + +#include "speakup.h" +#include "spk_priv.h" + +static int synth_registered, synthu_registered; +static int dev_opened; + +/* Latin1 version */ +static ssize_t speakup_file_write(struct file *fp, const char __user *buffer, + size_t nbytes, loff_t *ppos) +{ + size_t count = nbytes; + const char __user *ptr = buffer; + size_t bytes; + unsigned long flags; + u_char buf[256]; + + if (!synth) + return -ENODEV; + while (count > 0) { + bytes = min(count, sizeof(buf)); + if (copy_from_user(buf, ptr, bytes)) + return -EFAULT; + count -= bytes; + ptr += bytes; + spin_lock_irqsave(&speakup_info.spinlock, flags); + synth_write(buf, bytes); + spin_unlock_irqrestore(&speakup_info.spinlock, flags); + } + return (ssize_t)nbytes; +} + +/* UTF-8 version */ +static ssize_t speakup_file_writeu(struct file *fp, const char __user *buffer, + size_t nbytes, loff_t *ppos) +{ + size_t count = nbytes, consumed, want; + const char __user *ptr = buffer; + size_t bytes; + unsigned long flags; + unsigned char buf[256]; + u16 ubuf[256]; + size_t in, out; + + if (!synth) + return -ENODEV; + + want = 1; + while (count >= want) { + /* Copy some UTF-8 piece from userland */ + bytes = min(count, sizeof(buf)); + if (copy_from_user(buf, ptr, bytes)) + return -EFAULT; + + /* Convert to u16 */ + for (in = 0, out = 0; in < bytes; in += consumed) { + s32 value; + + value = synth_utf8_get(buf + in, bytes - in, &consumed, &want); + if (value == -1) { + /* Invalid or incomplete */ + + if (want > bytes - in) + /* We don't have it all yet, stop here + * and wait for the rest + */ + bytes = in; + + continue; + } + + if (value < 0x10000) + ubuf[out++] = value; + } + + count -= bytes; + ptr += bytes; + + /* And speak this up */ + if (out) { + spin_lock_irqsave(&speakup_info.spinlock, flags); + for (in = 0; in < out; in++) + synth_buffer_add(ubuf[in]); + synth_start(); + spin_unlock_irqrestore(&speakup_info.spinlock, flags); + } + } + + return (ssize_t)(nbytes - count); +} + +static ssize_t speakup_file_read(struct file *fp, char __user *buf, + size_t nbytes, loff_t *ppos) +{ + return 0; +} + +static int speakup_file_open(struct inode *ip, struct file *fp) +{ + if (!synth) + return -ENODEV; + if (xchg(&dev_opened, 1)) + return -EBUSY; + return 0; +} + +static int speakup_file_release(struct inode *ip, struct file *fp) +{ + dev_opened = 0; + return 0; +} + +static const struct file_operations synth_fops = { + .read = speakup_file_read, + .write = speakup_file_write, + .open = speakup_file_open, + .release = speakup_file_release, +}; + +static const struct file_operations synthu_fops = { + .read = speakup_file_read, + .write = speakup_file_writeu, + .open = speakup_file_open, + .release = speakup_file_release, +}; + +static struct miscdevice synth_device = { + .minor = MISC_DYNAMIC_MINOR, + .name = "synth", + .fops = &synth_fops, +}; + +static struct miscdevice synthu_device = { + .minor = MISC_DYNAMIC_MINOR, + .name = "synthu", + .fops = &synthu_fops, +}; + +void speakup_register_devsynth(void) +{ + if (!synth_registered) { + if (misc_register(&synth_device)) { + pr_warn("Couldn't initialize miscdevice /dev/synth.\n"); + } else { + pr_info("initialized device: /dev/synth, node (MAJOR %d, MINOR %d)\n", + MISC_MAJOR, synth_device.minor); + synth_registered = 1; + } + } + if (!synthu_registered) { + if (misc_register(&synthu_device)) { + pr_warn("Couldn't initialize miscdevice /dev/synthu.\n"); + } else { + pr_info("initialized device: /dev/synthu, node (MAJOR %d, MINOR %d)\n", + MISC_MAJOR, synthu_device.minor); + synthu_registered = 1; + } + } +} + +void speakup_unregister_devsynth(void) +{ + if (synth_registered) { + pr_info("speakup: unregistering synth device /dev/synth\n"); + misc_deregister(&synth_device); + synth_registered = 0; + } + if (synthu_registered) { + pr_info("speakup: unregistering synth device /dev/synthu\n"); + misc_deregister(&synthu_device); + synthu_registered = 0; + } +} -- cgit v1.3.1