This driver has a number of issues (accesses arbitrary I/O ports
without identifying the hardware, doesn't document what hardware it
supports, suspiciously inconsistent locking model, doesn't implement
WDIOC_SETTIMEOUT, potential integer overflow...)

The driver was added in 2003 and there's no evidence that it has any
recent user, all changes seem to be tree-wide, subsystem-wide, or the
result of static code analysis. So I believe we should simply drop
this legacy piece of code.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Message-ID: <20241011170710.484a257a@endymion.delvare>
---
 Documentation/watchdog/watchdog-parameters.rst |   10 
 drivers/watchdog/Kconfig                       |    8 
 drivers/watchdog/Makefile                      |    1 
 drivers/watchdog/cpu5wdt.c                     |  285 -------------------------
 4 files changed, 304 deletions(-)

--- linux-6.11.orig/Documentation/watchdog/watchdog-parameters.rst
+++ linux-6.11/Documentation/watchdog/watchdog-parameters.rst
@@ -120,16 +120,6 @@ modules.
 
 -------------------------------------------------
 
-cpu5wdt:
-    port:
-	base address of watchdog card, default is 0x91
-    verbose:
-	be verbose, default is 0 (no)
-    ticks:
-	count down ticks, default is 10000
-
--------------------------------------------------
-
 cpwd:
     wd0_timeout:
 	Default watchdog0 timeout in 1/10secs
--- linux-6.11.orig/drivers/watchdog/Kconfig
+++ linux-6.11/drivers/watchdog/Kconfig
@@ -1524,14 +1524,6 @@ config SBC7240_WDT
 	  To compile this driver as a module, choose M here: the
 	  module will be called sbc7240_wdt.
 
-config CPU5_WDT
-	tristate "SMA CPU5 Watchdog"
-	depends on (X86 || COMPILE_TEST) && HAS_IOPORT
-	help
-	  TBD.
-	  To compile this driver as a module, choose M here: the
-	  module will be called cpu5wdt.
-
 config SMSC_SCH311X_WDT
 	tristate "SMSC SCH311X Watchdog Timer"
 	depends on (X86 || COMPILE_TEST) && HAS_IOPORT
--- linux-6.11.orig/drivers/watchdog/Makefile
+++ linux-6.11/drivers/watchdog/Makefile
@@ -136,7 +136,6 @@ obj-$(CONFIG_RDC321X_WDT) += rdc321x_wdt
 obj-$(CONFIG_60XX_WDT) += sbc60xxwdt.o
 obj-$(CONFIG_SBC8360_WDT) += sbc8360.o
 obj-$(CONFIG_SBC7240_WDT) += sbc7240_wdt.o
-obj-$(CONFIG_CPU5_WDT) += cpu5wdt.o
 obj-$(CONFIG_SMSC_SCH311X_WDT) += sch311x_wdt.o
 obj-$(CONFIG_SMSC37B787_WDT) += smsc37b787_wdt.o
 obj-$(CONFIG_TQMX86_WDT) += tqmx86_wdt.o
--- linux-6.11.orig/drivers/watchdog/cpu5wdt.c
+++ /dev/null
@@ -1,285 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * sma cpu5 watchdog driver
- *
- * Copyright (C) 2003 Heiko Ronsdorf <hero@ihg.uni-duisburg.de>
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/module.h>
-#include <linux/moduleparam.h>
-#include <linux/types.h>
-#include <linux/errno.h>
-#include <linux/miscdevice.h>
-#include <linux/fs.h>
-#include <linux/ioport.h>
-#include <linux/timer.h>
-#include <linux/completion.h>
-#include <linux/jiffies.h>
-#include <linux/io.h>
-#include <linux/uaccess.h>
-#include <linux/watchdog.h>
-
-/* adjustable parameters */
-
-static int verbose;
-static int port = 0x91;
-static int ticks = 10000;
-static DEFINE_SPINLOCK(cpu5wdt_lock);
-
-#define PFX			"cpu5wdt: "
-
-#define CPU5WDT_EXTENT          0x0A
-
-#define CPU5WDT_STATUS_REG      0x00
-#define CPU5WDT_TIME_A_REG      0x02
-#define CPU5WDT_TIME_B_REG      0x03
-#define CPU5WDT_MODE_REG        0x04
-#define CPU5WDT_TRIGGER_REG     0x07
-#define CPU5WDT_ENABLE_REG      0x08
-#define CPU5WDT_RESET_REG       0x09
-
-#define CPU5WDT_INTERVAL	(HZ/10+1)
-
-/* some device data */
-
-static struct {
-	struct completion stop;
-	int running;
-	struct timer_list timer;
-	int queue;
-	int default_ticks;
-	unsigned long inuse;
-} cpu5wdt_device;
-
-/* generic helper functions */
-
-static void cpu5wdt_trigger(struct timer_list *unused)
-{
-	if (verbose > 2)
-		pr_debug("trigger at %i ticks\n", ticks);
-
-	if (cpu5wdt_device.running)
-		ticks--;
-
-	spin_lock(&cpu5wdt_lock);
-	/* keep watchdog alive */
-	outb(1, port + CPU5WDT_TRIGGER_REG);
-
-	/* requeue?? */
-	if (cpu5wdt_device.queue && ticks)
-		mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
-	else {
-		/* ticks doesn't matter anyway */
-		complete(&cpu5wdt_device.stop);
-	}
-	spin_unlock(&cpu5wdt_lock);
-
-}
-
-static void cpu5wdt_reset(void)
-{
-	ticks = cpu5wdt_device.default_ticks;
-
-	if (verbose)
-		pr_debug("reset (%i ticks)\n", (int) ticks);
-
-}
-
-static void cpu5wdt_start(void)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&cpu5wdt_lock, flags);
-	if (!cpu5wdt_device.queue) {
-		cpu5wdt_device.queue = 1;
-		outb(0, port + CPU5WDT_TIME_A_REG);
-		outb(0, port + CPU5WDT_TIME_B_REG);
-		outb(1, port + CPU5WDT_MODE_REG);
-		outb(0, port + CPU5WDT_RESET_REG);
-		outb(0, port + CPU5WDT_ENABLE_REG);
-		mod_timer(&cpu5wdt_device.timer, jiffies + CPU5WDT_INTERVAL);
-	}
-	/* if process dies, counter is not decremented */
-	cpu5wdt_device.running++;
-	spin_unlock_irqrestore(&cpu5wdt_lock, flags);
-}
-
-static int cpu5wdt_stop(void)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&cpu5wdt_lock, flags);
-	if (cpu5wdt_device.running)
-		cpu5wdt_device.running = 0;
-	ticks = cpu5wdt_device.default_ticks;
-	spin_unlock_irqrestore(&cpu5wdt_lock, flags);
-	if (verbose)
-		pr_crit("stop not possible\n");
-	return -EIO;
-}
-
-/* filesystem operations */
-
-static int cpu5wdt_open(struct inode *inode, struct file *file)
-{
-	if (test_and_set_bit(0, &cpu5wdt_device.inuse))
-		return -EBUSY;
-	return stream_open(inode, file);
-}
-
-static int cpu5wdt_release(struct inode *inode, struct file *file)
-{
-	clear_bit(0, &cpu5wdt_device.inuse);
-	return 0;
-}
-
-static long cpu5wdt_ioctl(struct file *file, unsigned int cmd,
-						unsigned long arg)
-{
-	void __user *argp = (void __user *)arg;
-	int __user *p = argp;
-	unsigned int value;
-	static const struct watchdog_info ident = {
-		.options = WDIOF_CARDRESET,
-		.identity = "CPU5 WDT",
-	};
-
-	switch (cmd) {
-	case WDIOC_GETSUPPORT:
-		if (copy_to_user(argp, &ident, sizeof(ident)))
-			return -EFAULT;
-		break;
-	case WDIOC_GETSTATUS:
-		value = inb(port + CPU5WDT_STATUS_REG);
-		value = (value >> 2) & 1;
-		return put_user(value, p);
-	case WDIOC_GETBOOTSTATUS:
-		return put_user(0, p);
-	case WDIOC_SETOPTIONS:
-		if (get_user(value, p))
-			return -EFAULT;
-		if (value & WDIOS_ENABLECARD)
-			cpu5wdt_start();
-		if (value & WDIOS_DISABLECARD)
-			cpu5wdt_stop();
-		break;
-	case WDIOC_KEEPALIVE:
-		cpu5wdt_reset();
-		break;
-	default:
-		return -ENOTTY;
-	}
-	return 0;
-}
-
-static ssize_t cpu5wdt_write(struct file *file, const char __user *buf,
-						size_t count, loff_t *ppos)
-{
-	if (!count)
-		return -EIO;
-	cpu5wdt_reset();
-	return count;
-}
-
-static const struct file_operations cpu5wdt_fops = {
-	.owner		= THIS_MODULE,
-	.llseek		= no_llseek,
-	.unlocked_ioctl	= cpu5wdt_ioctl,
-	.compat_ioctl	= compat_ptr_ioctl,
-	.open		= cpu5wdt_open,
-	.write		= cpu5wdt_write,
-	.release	= cpu5wdt_release,
-};
-
-static struct miscdevice cpu5wdt_misc = {
-	.minor	= WATCHDOG_MINOR,
-	.name	= "watchdog",
-	.fops	= &cpu5wdt_fops,
-};
-
-/* init/exit function */
-
-static int cpu5wdt_init(void)
-{
-	unsigned int val;
-	int err;
-
-	if (verbose)
-		pr_debug("port=0x%x, verbose=%i\n", port, verbose);
-
-	init_completion(&cpu5wdt_device.stop);
-	cpu5wdt_device.queue = 0;
-	timer_setup(&cpu5wdt_device.timer, cpu5wdt_trigger, 0);
-	cpu5wdt_device.default_ticks = ticks;
-
-	if (!request_region(port, CPU5WDT_EXTENT, PFX)) {
-		pr_err("request_region failed\n");
-		err = -EBUSY;
-		goto no_port;
-	}
-
-	/* watchdog reboot? */
-	val = inb(port + CPU5WDT_STATUS_REG);
-	val = (val >> 2) & 1;
-	if (!val)
-		pr_info("sorry, was my fault\n");
-
-	err = misc_register(&cpu5wdt_misc);
-	if (err < 0) {
-		pr_err("misc_register failed\n");
-		goto no_misc;
-	}
-
-
-	pr_info("init success\n");
-	return 0;
-
-no_misc:
-	release_region(port, CPU5WDT_EXTENT);
-no_port:
-	return err;
-}
-
-static int cpu5wdt_init_module(void)
-{
-	return cpu5wdt_init();
-}
-
-static void cpu5wdt_exit(void)
-{
-	if (cpu5wdt_device.queue) {
-		cpu5wdt_device.queue = 0;
-		wait_for_completion(&cpu5wdt_device.stop);
-		timer_shutdown_sync(&cpu5wdt_device.timer);
-	}
-
-	misc_deregister(&cpu5wdt_misc);
-
-	release_region(port, CPU5WDT_EXTENT);
-
-}
-
-static void cpu5wdt_exit_module(void)
-{
-	cpu5wdt_exit();
-}
-
-/* module entry points */
-
-module_init(cpu5wdt_init_module);
-module_exit(cpu5wdt_exit_module);
-
-MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
-MODULE_DESCRIPTION("sma cpu5 watchdog driver");
-MODULE_LICENSE("GPL");
-
-module_param_hw(port, int, ioport, 0);
-MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
-
-module_param(verbose, int, 0);
-MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");
-
-module_param(ticks, int, 0);
-MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");


-- 
Jean Delvare
SUSE L3 Support

On 10/15/24 04:37, Jean Delvare wrote:
> This driver has a number of issues (accesses arbitrary I/O ports
> without identifying the hardware, doesn't document what hardware it
> supports, suspiciously inconsistent locking model, doesn't implement
> WDIOC_SETTIMEOUT, potential integer overflow...)
> 
> The driver was added in 2003 and there's no evidence that it has any
> recent user, all changes seem to be tree-wide, subsystem-wide, or the
> result of static code analysis. So I believe we should simply drop
> this legacy piece of code.
> 
> Signed-off-by: Jean Delvare <jdelvare@suse.de>
> Message-ID: <20241011170710.484a257a@endymion.delvare>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

Ultimately we should consider removing all watchdog drivers not implementing
the watchdog API, or at least declare them deprecated.

Guenter