From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/input/serio/ps2mult.c | 293 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 293 insertions(+) create mode 100644 drivers/input/serio/ps2mult.c (limited to 'drivers/input/serio/ps2mult.c') diff --git a/drivers/input/serio/ps2mult.c b/drivers/input/serio/ps2mult.c new file mode 100644 index 000000000..27d554b59 --- /dev/null +++ b/drivers/input/serio/ps2mult.c @@ -0,0 +1,293 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * TQC PS/2 Multiplexer driver + * + * Copyright (C) 2010 Dmitry Eremin-Solenikov + */ + + +#include +#include +#include +#include + +MODULE_AUTHOR("Dmitry Eremin-Solenikov "); +MODULE_DESCRIPTION("TQC PS/2 Multiplexer driver"); +MODULE_LICENSE("GPL"); + +#define PS2MULT_KB_SELECTOR 0xA0 +#define PS2MULT_MS_SELECTOR 0xA1 +#define PS2MULT_ESCAPE 0x7D +#define PS2MULT_BSYNC 0x7E +#define PS2MULT_SESSION_START 0x55 +#define PS2MULT_SESSION_END 0x56 + +struct ps2mult_port { + struct serio *serio; + unsigned char sel; + bool registered; +}; + +#define PS2MULT_NUM_PORTS 2 +#define PS2MULT_KBD_PORT 0 +#define PS2MULT_MOUSE_PORT 1 + +struct ps2mult { + struct serio *mx_serio; + struct ps2mult_port ports[PS2MULT_NUM_PORTS]; + + spinlock_t lock; + struct ps2mult_port *in_port; + struct ps2mult_port *out_port; + bool escape; +}; + +/* First MUST come PS2MULT_NUM_PORTS selectors */ +static const unsigned char ps2mult_controls[] = { + PS2MULT_KB_SELECTOR, PS2MULT_MS_SELECTOR, + PS2MULT_ESCAPE, PS2MULT_BSYNC, + PS2MULT_SESSION_START, PS2MULT_SESSION_END, +}; + +static const struct serio_device_id ps2mult_serio_ids[] = { + { + .type = SERIO_RS232, + .proto = SERIO_PS2MULT, + .id = SERIO_ANY, + .extra = SERIO_ANY, + }, + { 0 } +}; + +MODULE_DEVICE_TABLE(serio, ps2mult_serio_ids); + +static void ps2mult_select_port(struct ps2mult *psm, struct ps2mult_port *port) +{ + struct serio *mx_serio = psm->mx_serio; + + serio_write(mx_serio, port->sel); + psm->out_port = port; + dev_dbg(&mx_serio->dev, "switched to sel %02x\n", port->sel); +} + +static int ps2mult_serio_write(struct serio *serio, unsigned char data) +{ + struct serio *mx_port = serio->parent; + struct ps2mult *psm = serio_get_drvdata(mx_port); + struct ps2mult_port *port = serio->port_data; + bool need_escape; + + guard(spinlock_irqsave)(&psm->lock); + + if (psm->out_port != port) + ps2mult_select_port(psm, port); + + need_escape = memchr(ps2mult_controls, data, sizeof(ps2mult_controls)); + + dev_dbg(&serio->dev, + "write: %s%02x\n", need_escape ? "ESC " : "", data); + + if (need_escape) + serio_write(mx_port, PS2MULT_ESCAPE); + + serio_write(mx_port, data); + + return 0; +} + +static int ps2mult_serio_start(struct serio *serio) +{ + struct ps2mult *psm = serio_get_drvdata(serio->parent); + struct ps2mult_port *port = serio->port_data; + + guard(spinlock_irqsave)(&psm->lock); + + port->registered = true; + + return 0; +} + +static void ps2mult_serio_stop(struct serio *serio) +{ + struct ps2mult *psm = serio_get_drvdata(serio->parent); + struct ps2mult_port *port = serio->port_data; + + guard(spinlock_irqsave)(&psm->lock); + + port->registered = false; +} + +static int ps2mult_create_port(struct ps2mult *psm, int i) +{ + struct serio *mx_serio = psm->mx_serio; + struct serio *serio; + + serio = kzalloc_obj(*serio); + if (!serio) + return -ENOMEM; + + strscpy(serio->name, "TQC PS/2 Multiplexer", sizeof(serio->name)); + snprintf(serio->phys, sizeof(serio->phys), + "%s/port%d", mx_serio->phys, i); + serio->id.type = SERIO_8042; + serio->write = ps2mult_serio_write; + serio->start = ps2mult_serio_start; + serio->stop = ps2mult_serio_stop; + serio->parent = psm->mx_serio; + serio->port_data = &psm->ports[i]; + + psm->ports[i].serio = serio; + + return 0; +} + +static void ps2mult_reset(struct ps2mult *psm) +{ + guard(spinlock_irqsave)(&psm->lock); + + serio_write(psm->mx_serio, PS2MULT_SESSION_END); + serio_write(psm->mx_serio, PS2MULT_SESSION_START); + + ps2mult_select_port(psm, &psm->ports[PS2MULT_KBD_PORT]); +} + +static int ps2mult_connect(struct serio *serio, struct serio_driver *drv) +{ + struct ps2mult *psm; + int i; + int error; + + if (!serio->write) + return -EINVAL; + + psm = kzalloc_obj(*psm); + if (!psm) + return -ENOMEM; + + spin_lock_init(&psm->lock); + psm->mx_serio = serio; + + for (i = 0; i < PS2MULT_NUM_PORTS; i++) { + psm->ports[i].sel = ps2mult_controls[i]; + error = ps2mult_create_port(psm, i); + if (error) + goto err_out; + } + + psm->in_port = psm->out_port = &psm->ports[PS2MULT_KBD_PORT]; + + serio_set_drvdata(serio, psm); + error = serio_open(serio, drv); + if (error) + goto err_out; + + ps2mult_reset(psm); + + for (i = 0; i < PS2MULT_NUM_PORTS; i++) { + struct serio *s = psm->ports[i].serio; + + dev_info(&serio->dev, "%s port at %s\n", s->name, serio->phys); + serio_register_port(s); + } + + return 0; + +err_out: + while (--i >= 0) + kfree(psm->ports[i].serio); + kfree(psm); + return error; +} + +static void ps2mult_disconnect(struct serio *serio) +{ + struct ps2mult *psm = serio_get_drvdata(serio); + + /* Note that serio core already take care of children ports */ + serio_write(serio, PS2MULT_SESSION_END); + serio_close(serio); + kfree(psm); + + serio_set_drvdata(serio, NULL); +} + +static int ps2mult_reconnect(struct serio *serio) +{ + struct ps2mult *psm = serio_get_drvdata(serio); + + ps2mult_reset(psm); + + return 0; +} + +static irqreturn_t ps2mult_interrupt(struct serio *serio, + unsigned char data, unsigned int dfl) +{ + struct ps2mult *psm = serio_get_drvdata(serio); + struct ps2mult_port *in_port; + + dev_dbg(&serio->dev, "Received %02x flags %02x\n", data, dfl); + + guard(spinlock_irqsave)(&psm->lock); + + if (psm->escape) { + psm->escape = false; + in_port = psm->in_port; + if (in_port->registered) + serio_interrupt(in_port->serio, data, dfl); + goto out; + } + + switch (data) { + case PS2MULT_ESCAPE: + dev_dbg(&serio->dev, "ESCAPE\n"); + psm->escape = true; + break; + + case PS2MULT_BSYNC: + dev_dbg(&serio->dev, "BSYNC\n"); + psm->in_port = psm->out_port; + break; + + case PS2MULT_SESSION_START: + dev_dbg(&serio->dev, "SS\n"); + break; + + case PS2MULT_SESSION_END: + dev_dbg(&serio->dev, "SE\n"); + break; + + case PS2MULT_KB_SELECTOR: + dev_dbg(&serio->dev, "KB\n"); + psm->in_port = &psm->ports[PS2MULT_KBD_PORT]; + break; + + case PS2MULT_MS_SELECTOR: + dev_dbg(&serio->dev, "MS\n"); + psm->in_port = &psm->ports[PS2MULT_MOUSE_PORT]; + break; + + default: + in_port = psm->in_port; + if (in_port->registered) + serio_interrupt(in_port->serio, data, dfl); + break; + } + + out: + return IRQ_HANDLED; +} + +static struct serio_driver ps2mult_drv = { + .driver = { + .name = "ps2mult", + }, + .description = "TQC PS/2 Multiplexer driver", + .id_table = ps2mult_serio_ids, + .interrupt = ps2mult_interrupt, + .connect = ps2mult_connect, + .disconnect = ps2mult_disconnect, + .reconnect = ps2mult_reconnect, +}; + +module_serio_driver(ps2mult_drv); -- cgit v1.3.1