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/input/serio/parkbd.c | 222 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 222 insertions(+) create mode 100644 drivers/input/serio/parkbd.c (limited to 'drivers/input/serio/parkbd.c') diff --git a/drivers/input/serio/parkbd.c b/drivers/input/serio/parkbd.c new file mode 100644 index 000000000..09a24413d --- /dev/null +++ b/drivers/input/serio/parkbd.c @@ -0,0 +1,222 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Parallel port to Keyboard port adapter driver for Linux + * + * Copyright (c) 1999-2004 Vojtech Pavlik + */ + + +/* + * To connect an AT or XT keyboard to the parallel port, a fairly simple adapter + * can be made: + * + * Parallel port Keyboard port + * + * +5V --------------------- +5V (4) + * + * ______ + * +5V -------|______|--. + * | + * ACK (10) ------------| + * |--- KBD CLOCK (5) + * STROBE (1) ---|<|----' + * + * ______ + * +5V -------|______|--. + * | + * BUSY (11) -----------| + * |--- KBD DATA (1) + * AUTOFD (14) --|<|----' + * + * GND (18-25) ------------- GND (3) + * + * The diodes can be fairly any type, and the resistors should be somewhere + * around 5 kOhm, but the adapter will likely work without the resistors, + * too. + * + * The +5V source can be taken either from USB, from mouse or keyboard ports, + * or from a joystick port. Unfortunately, the parallel port of a PC doesn't + * have a +5V pin, and feeding the keyboard from signal pins is out of question + * with 300 mA power reqirement of a typical AT keyboard. + */ + +#include +#include +#include +#include +#include + +MODULE_AUTHOR("Vojtech Pavlik "); +MODULE_DESCRIPTION("Parallel port to Keyboard port adapter driver"); +MODULE_LICENSE("GPL"); + +static unsigned int parkbd_pp_no; +module_param_named(port, parkbd_pp_no, int, 0); +MODULE_PARM_DESC(port, "Parallel port the adapter is connected to (default is 0)"); + +static unsigned int parkbd_mode = SERIO_8042; +module_param_named(mode, parkbd_mode, uint, 0); +MODULE_PARM_DESC(mode, "Mode of operation: XT = 0/AT = 1 (default)"); + +#define PARKBD_CLOCK 0x01 /* Strobe & Ack */ +#define PARKBD_DATA 0x02 /* AutoFd & Busy */ + +static int parkbd_buffer; +static int parkbd_counter; +static unsigned long parkbd_last; +static int parkbd_writing; +static unsigned long parkbd_start; + +static struct pardevice *parkbd_dev; +static struct serio *parkbd_port; + +static int parkbd_readlines(void) +{ + return (parport_read_status(parkbd_dev->port) >> 6) ^ 2; +} + +static void parkbd_writelines(int data) +{ + parport_write_control(parkbd_dev->port, (~data & 3) | 0x10); +} + +static int parkbd_write(struct serio *port, unsigned char c) +{ + unsigned char p; + + if (!parkbd_mode) return -1; + + p = c ^ (c >> 4); + p = p ^ (p >> 2); + p = p ^ (p >> 1); + + parkbd_counter = 0; + parkbd_writing = 1; + parkbd_buffer = c | (((int) (~p & 1)) << 8) | 0x600; + + parkbd_writelines(2); + + return 0; +} + +static void parkbd_interrupt(void *dev_id) +{ + + if (parkbd_writing) { + + if (parkbd_counter && ((parkbd_counter == 11) || time_after(jiffies, parkbd_last + HZ/100))) { + parkbd_counter = 0; + parkbd_buffer = 0; + parkbd_writing = 0; + parkbd_writelines(3); + return; + } + + parkbd_writelines(((parkbd_buffer >> parkbd_counter++) & 1) | 2); + + if (parkbd_counter == 11) { + parkbd_counter = 0; + parkbd_buffer = 0; + parkbd_writing = 0; + parkbd_writelines(3); + } + + } else { + + if ((parkbd_counter == parkbd_mode + 10) || time_after(jiffies, parkbd_last + HZ/100)) { + parkbd_counter = 0; + parkbd_buffer = 0; + } + + parkbd_buffer |= (parkbd_readlines() >> 1) << parkbd_counter++; + + if (parkbd_counter == parkbd_mode + 10) + serio_interrupt(parkbd_port, (parkbd_buffer >> (2 - parkbd_mode)) & 0xff, 0); + } + + parkbd_last = jiffies; +} + +static int parkbd_getport(struct parport *pp) +{ + struct pardev_cb parkbd_parport_cb; + + memset(&parkbd_parport_cb, 0, sizeof(parkbd_parport_cb)); + parkbd_parport_cb.irq_func = parkbd_interrupt; + parkbd_parport_cb.flags = PARPORT_FLAG_EXCL; + + parkbd_dev = parport_register_dev_model(pp, "parkbd", + &parkbd_parport_cb, 0); + + if (!parkbd_dev) + return -ENODEV; + + if (parport_claim(parkbd_dev)) { + parport_unregister_device(parkbd_dev); + return -EBUSY; + } + + parkbd_start = jiffies; + + return 0; +} + +static struct serio *parkbd_allocate_serio(void) +{ + struct serio *serio; + + serio = kzalloc_obj(*serio); + if (serio) { + serio->id.type = parkbd_mode; + serio->write = parkbd_write; + strscpy(serio->name, "PARKBD AT/XT keyboard adapter", sizeof(serio->name)); + snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", parkbd_dev->port->name); + } + + return serio; +} + +static void parkbd_attach(struct parport *pp) +{ + if (pp->number != parkbd_pp_no) { + pr_debug("Not using parport%d.\n", pp->number); + return; + } + + if (parkbd_getport(pp)) + return; + + parkbd_port = parkbd_allocate_serio(); + if (!parkbd_port) { + parport_release(parkbd_dev); + parport_unregister_device(parkbd_dev); + return; + } + + parkbd_writelines(3); + + serio_register_port(parkbd_port); + + printk(KERN_INFO "serio: PARKBD %s adapter on %s\n", + parkbd_mode ? "AT" : "XT", parkbd_dev->port->name); + + return; +} + +static void parkbd_detach(struct parport *port) +{ + if (!parkbd_port || port->number != parkbd_pp_no) + return; + + parport_release(parkbd_dev); + serio_unregister_port(parkbd_port); + parport_unregister_device(parkbd_dev); + parkbd_port = NULL; +} + +static struct parport_driver parkbd_parport_driver = { + .name = "parkbd", + .match_port = parkbd_attach, + .detach = parkbd_detach, +}; +module_parport_driver(parkbd_parport_driver); -- cgit v1.3.1