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linux/drivers/watchdog/nv_tco.c
Alexander A. Klimov 2ab77a34d0 watchdog: Replace HTTP links with HTTPS ones 
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  If not .svg:
    For each line:
      If doesn't contain `\bxmlns\b`:
        For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
	  If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`:
            If both the HTTP and HTTPS versions
            return 200 OK and serve the same content:
              Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200713205821.38223-1-grandmaster@al2klimov.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-08-05 18:43:01 +02:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* nv_tco 0.01: TCO timer driver for NV chipsets
*
* (c) Copyright 2005 Google Inc., All Rights Reserved.
*
* Based off i8xx_tco.c:
* (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
* Reserved.
* https://www.kernelconcepts.de
*
* TCO timer driver for NV chipsets
* based on softdog.c by Alan Cox <alan@redhat.com>
*/
/*
* Includes, defines, variables, module parameters, ...
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/platform_device.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "nv_tco.h"
/* Module and version information */
#define TCO_VERSION "0.01"
#define TCO_MODULE_NAME "NV_TCO"
#define TCO_DRIVER_NAME TCO_MODULE_NAME ", v" TCO_VERSION
/* internal variables */
static unsigned int tcobase;
static DEFINE_SPINLOCK(tco_lock); /* Guards the hardware */
static unsigned long timer_alive;
static char tco_expect_close;
static struct pci_dev *tco_pci;
/* the watchdog platform device */
static struct platform_device *nv_tco_platform_device;
/* module parameters */
#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat (2<heartbeat<39) */
static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
"default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
" (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/*
* Some TCO specific functions
*/
static inline unsigned char seconds_to_ticks(int seconds)
{
/* the internal timer is stored as ticks which decrement
* every 0.6 seconds */
return (seconds * 10) / 6;
}
static void tco_timer_start(void)
{
u32 val;
unsigned long flags;
spin_lock_irqsave(&tco_lock, flags);
val = inl(TCO_CNT(tcobase));
val &= ~TCO_CNT_TCOHALT;
outl(val, TCO_CNT(tcobase));
spin_unlock_irqrestore(&tco_lock, flags);
}
static void tco_timer_stop(void)
{
u32 val;
unsigned long flags;
spin_lock_irqsave(&tco_lock, flags);
val = inl(TCO_CNT(tcobase));
val |= TCO_CNT_TCOHALT;
outl(val, TCO_CNT(tcobase));
spin_unlock_irqrestore(&tco_lock, flags);
}
static void tco_timer_keepalive(void)
{
unsigned long flags;
spin_lock_irqsave(&tco_lock, flags);
outb(0x01, TCO_RLD(tcobase));
spin_unlock_irqrestore(&tco_lock, flags);
}
static int tco_timer_set_heartbeat(int t)
{
int ret = 0;
unsigned char tmrval;
unsigned long flags;
u8 val;
/*
* note seconds_to_ticks(t) > t, so if t > 0x3f, so is
* tmrval=seconds_to_ticks(t). Check that the count in seconds isn't
* out of range on it's own (to avoid overflow in tmrval).
*/
if (t < 0 || t > 0x3f)
return -EINVAL;
tmrval = seconds_to_ticks(t);
/* "Values of 0h-3h are ignored and should not be attempted" */
if (tmrval > 0x3f || tmrval < 0x04)
return -EINVAL;
/* Write new heartbeat to watchdog */
spin_lock_irqsave(&tco_lock, flags);
val = inb(TCO_TMR(tcobase));
val &= 0xc0;
val |= tmrval;
outb(val, TCO_TMR(tcobase));
val = inb(TCO_TMR(tcobase));
if ((val & 0x3f) != tmrval)
ret = -EINVAL;
spin_unlock_irqrestore(&tco_lock, flags);
if (ret)
return ret;
heartbeat = t;
return 0;
}
/*
* /dev/watchdog handling
*/
static int nv_tco_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */
if (test_and_set_bit(0, &timer_alive))
return -EBUSY;
/* Reload and activate timer */
tco_timer_keepalive();
tco_timer_start();
return stream_open(inode, file);
}
static int nv_tco_release(struct inode *inode, struct file *file)
{
/* Shut off the timer */
if (tco_expect_close == 42) {
tco_timer_stop();
} else {
pr_crit("Unexpected close, not stopping watchdog!\n");
tco_timer_keepalive();
}
clear_bit(0, &timer_alive);
tco_expect_close = 0;
return 0;
}
static ssize_t nv_tco_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
/* See if we got the magic character 'V' and reload the timer */
if (len) {
if (!nowayout) {
size_t i;
/*
* note: just in case someone wrote the magic character
* five months ago...
*/
tco_expect_close = 0;
/*
* scan to see whether or not we got the magic
* character
*/
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
tco_expect_close = 42;
}
}
/* someone wrote to us, we should reload the timer */
tco_timer_keepalive();
}
return len;
}
static long nv_tco_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int new_options, retval = -EINVAL;
int new_heartbeat;
void __user *argp = (void __user *)arg;
int __user *p = argp;
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = TCO_MODULE_NAME,
};
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_SETOPTIONS:
if (get_user(new_options, p))
return -EFAULT;
if (new_options & WDIOS_DISABLECARD) {
tco_timer_stop();
retval = 0;
}
if (new_options & WDIOS_ENABLECARD) {
tco_timer_keepalive();
tco_timer_start();
retval = 0;
}
return retval;
case WDIOC_KEEPALIVE:
tco_timer_keepalive();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_heartbeat, p))
return -EFAULT;
if (tco_timer_set_heartbeat(new_heartbeat))
return -EINVAL;
tco_timer_keepalive();
fallthrough;
case WDIOC_GETTIMEOUT:
return put_user(heartbeat, p);
default:
return -ENOTTY;
}
}
/*
* Kernel Interfaces
*/
static const struct file_operations nv_tco_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = nv_tco_write,
.unlocked_ioctl = nv_tco_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = nv_tco_open,
.release = nv_tco_release,
};
static struct miscdevice nv_tco_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &nv_tco_fops,
};
/*
* Data for PCI driver interface
*
* This data only exists for exporting the supported
* PCI ids via MODULE_DEVICE_TABLE. We do not actually
* register a pci_driver, because someone else might one day
* want to register another driver on the same PCI id.
*/
static const struct pci_device_id tco_pci_tbl[] = {
{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS,
PCI_ANY_ID, PCI_ANY_ID, },
{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS,
PCI_ANY_ID, PCI_ANY_ID, },
{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP78S_SMBUS,
PCI_ANY_ID, PCI_ANY_ID, },
{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_SMBUS,
PCI_ANY_ID, PCI_ANY_ID, },
{ 0, }, /* End of list */
};
MODULE_DEVICE_TABLE(pci, tco_pci_tbl);
/*
* Init & exit routines
*/
static unsigned char nv_tco_getdevice(void)
{
struct pci_dev *dev = NULL;
u32 val;
/* Find the PCI device */
for_each_pci_dev(dev) {
if (pci_match_id(tco_pci_tbl, dev) != NULL) {
tco_pci = dev;
break;
}
}
if (!tco_pci)
return 0;
/* Find the base io port */
pci_read_config_dword(tco_pci, 0x64, &val);
val &= 0xffff;
if (val == 0x0001 || val == 0x0000) {
/* Something is wrong here, bar isn't setup */
pr_err("failed to get tcobase address\n");
return 0;
}
val &= 0xff00;
tcobase = val + 0x40;
if (!request_region(tcobase, 0x10, "NV TCO")) {
pr_err("I/O address 0x%04x already in use\n", tcobase);
return 0;
}
/* Set a reasonable heartbeat before we stop the timer */
tco_timer_set_heartbeat(30);
/*
* Stop the TCO before we change anything so we don't race with
* a zeroed timer.
*/
tco_timer_keepalive();
tco_timer_stop();
/* Disable SMI caused by TCO */
if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) {
pr_err("I/O address 0x%04x already in use\n",
MCP51_SMI_EN(tcobase));
goto out;
}
val = inl(MCP51_SMI_EN(tcobase));
val &= ~MCP51_SMI_EN_TCO;
outl(val, MCP51_SMI_EN(tcobase));
val = inl(MCP51_SMI_EN(tcobase));
release_region(MCP51_SMI_EN(tcobase), 4);
if (val & MCP51_SMI_EN_TCO) {
pr_err("Could not disable SMI caused by TCO\n");
goto out;
}
/* Check chipset's NO_REBOOT bit */
pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT;
pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) {
pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n");
goto out;
}
return 1;
out:
release_region(tcobase, 0x10);
return 0;
}
static int nv_tco_init(struct platform_device *dev)
{
int ret;
/* Check whether or not the hardware watchdog is there */
if (!nv_tco_getdevice())
return -ENODEV;
/* Check to see if last reboot was due to watchdog timeout */
pr_info("Watchdog reboot %sdetected\n",
inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not ");
/* Clear out the old status */
outl(TCO_STS_RESET, TCO_STS(tcobase));
/*
* Check that the heartbeat value is within it's range.
* If not, reset to the default.
*/
if (tco_timer_set_heartbeat(heartbeat)) {
heartbeat = WATCHDOG_HEARTBEAT;
tco_timer_set_heartbeat(heartbeat);
pr_info("heartbeat value must be 2<heartbeat<39, using %d\n",
heartbeat);
}
ret = misc_register(&nv_tco_miscdev);
if (ret != 0) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto unreg_region;
}
clear_bit(0, &timer_alive);
tco_timer_stop();
pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n",
tcobase, heartbeat, nowayout);
return 0;
unreg_region:
release_region(tcobase, 0x10);
return ret;
}
static void nv_tco_cleanup(void)
{
u32 val;
/* Stop the timer before we leave */
if (!nowayout)
tco_timer_stop();
/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) {
pr_crit("Couldn't unset REBOOT bit. Machine may soon reset\n");
}
/* Deregister */
misc_deregister(&nv_tco_miscdev);
release_region(tcobase, 0x10);
}
static int nv_tco_remove(struct platform_device *dev)
{
if (tcobase)
nv_tco_cleanup();
return 0;
}
static void nv_tco_shutdown(struct platform_device *dev)
{
u32 val;
tco_timer_stop();
/* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not
* unset during shutdown. */
pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
}
static struct platform_driver nv_tco_driver = {
.probe = nv_tco_init,
.remove = nv_tco_remove,
.shutdown = nv_tco_shutdown,
.driver = {
.name = TCO_MODULE_NAME,
},
};
static int __init nv_tco_init_module(void)
{
int err;
pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION);
err = platform_driver_register(&nv_tco_driver);
if (err)
return err;
nv_tco_platform_device = platform_device_register_simple(
TCO_MODULE_NAME, -1, NULL, 0);
if (IS_ERR(nv_tco_platform_device)) {
err = PTR_ERR(nv_tco_platform_device);
goto unreg_platform_driver;
}
return 0;
unreg_platform_driver:
platform_driver_unregister(&nv_tco_driver);
return err;
}
static void __exit nv_tco_cleanup_module(void)
{
platform_device_unregister(nv_tco_platform_device);
platform_driver_unregister(&nv_tco_driver);
pr_info("NV TCO Watchdog Module Unloaded\n");
}
module_init(nv_tco_init_module);
module_exit(nv_tco_cleanup_module);
MODULE_AUTHOR("Mike Waychison");
MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
MODULE_LICENSE("GPL");
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