/* * Watchdog driver for z/VM and LPAR using the diag 288 interface. * * Under z/VM, expiration of the watchdog will send a "system restart" command * to CP. * * The command can be altered using the module parameter "cmd". This is * not recommended because it's only supported on z/VM but not whith LPAR. * * On LPAR, the watchdog will always trigger a system restart. the module * paramter cmd is meaningless here. * * * Copyright IBM Corp. 2004, 2013 * Author(s): Arnd Bergmann (arndb@de.ibm.com) * Philipp Hachtmann (phacht@de.ibm.com) * */ #define KMSG_COMPONENT "diag288_wdt" #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #define MAX_CMDLEN 240 #define DEFAULT_CMD "SYSTEM RESTART" #define MIN_INTERVAL 15 /* Minimal time supported by diag88 */ #define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */ #define WDT_DEFAULT_TIMEOUT 30 /* Function codes - init, change, cancel */ #define WDT_FUNC_INIT 0 #define WDT_FUNC_CHANGE 1 #define WDT_FUNC_CANCEL 2 #define WDT_FUNC_CONCEAL 0x80000000 /* Action codes for LPAR watchdog */ #define LPARWDT_RESTART 0 static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD; static bool conceal_on; static bool nowayout_info = WATCHDOG_NOWAYOUT; MODULE_LICENSE("GPL"); MODULE_AUTHOR("Arnd Bergmann "); MODULE_AUTHOR("Philipp Hachtmann "); MODULE_DESCRIPTION("System z diag288 Watchdog Timer"); module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644); MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)"); module_param_named(conceal, conceal_on, bool, 0644); MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)"); module_param_named(nowayout, nowayout_info, bool, 0444); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); MODULE_ALIAS("vmwatchdog"); static int __diag288(unsigned int func, unsigned int timeout, unsigned long action, unsigned int len) { register unsigned long __func asm("2") = func; register unsigned long __timeout asm("3") = timeout; register unsigned long __action asm("4") = action; register unsigned long __len asm("5") = len; int err; err = -EINVAL; asm volatile( " diag %1, %3, 0x288\n" "0: la %0, 0\n" "1:\n" EX_TABLE(0b, 1b) : "+d" (err) : "d"(__func), "d"(__timeout), "d"(__action), "d"(__len) : "1", "cc"); return err; } static int __diag288_vm(unsigned int func, unsigned int timeout, char *cmd, size_t len) { diag_stat_inc(DIAG_STAT_X288); return __diag288(func, timeout, virt_to_phys(cmd), len); } static int __diag288_lpar(unsigned int func, unsigned int timeout, unsigned long action) { diag_stat_inc(DIAG_STAT_X288); return __diag288(func, timeout, action, 0); } static unsigned long wdt_status; #define DIAG_WDOG_BUSY 0 static int wdt_start(struct watchdog_device *dev) { char *ebc_cmd; size_t len; int ret; unsigned int func; if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) return -EBUSY; ret = -ENODEV; if (MACHINE_IS_VM) { ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); if (!ebc_cmd) { clear_bit(DIAG_WDOG_BUSY, &wdt_status); return -ENOMEM; } len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); ASCEBC(ebc_cmd, MAX_CMDLEN); EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) : WDT_FUNC_INIT; ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); WARN_ON(ret != 0); kfree(ebc_cmd); } else { ret = __diag288_lpar(WDT_FUNC_INIT, dev->timeout, LPARWDT_RESTART); } if (ret) { pr_err("The watchdog cannot be activated\n"); clear_bit(DIAG_WDOG_BUSY, &wdt_status); return ret; } return 0; } static int wdt_stop(struct watchdog_device *dev) { int ret; diag_stat_inc(DIAG_STAT_X288); ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0); clear_bit(DIAG_WDOG_BUSY, &wdt_status); return ret; } static int wdt_ping(struct watchdog_device *dev) { char *ebc_cmd; size_t len; int ret; unsigned int func; ret = -ENODEV; if (MACHINE_IS_VM) { ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); if (!ebc_cmd) return -ENOMEM; len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); ASCEBC(ebc_cmd, MAX_CMDLEN); EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); /* * It seems to be ok to z/VM to use the init function to * retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must * be used when the watchdog is running. */ func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) : WDT_FUNC_INIT; ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); WARN_ON(ret != 0); kfree(ebc_cmd); } else { ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0); } if (ret) pr_err("The watchdog timer cannot be started or reset\n"); return ret; } static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to) { dev->timeout = new_to; return wdt_ping(dev); } static struct watchdog_ops wdt_ops = { .owner = THIS_MODULE, .start = wdt_start, .stop = wdt_stop, .ping = wdt_ping, .set_timeout = wdt_set_timeout, }; static struct watchdog_info wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .firmware_version = 0, .identity = "z Watchdog", }; static struct watchdog_device wdt_dev = { .parent = NULL, .info = &wdt_info, .ops = &wdt_ops, .bootstatus = 0, .timeout = WDT_DEFAULT_TIMEOUT, .min_timeout = MIN_INTERVAL, .max_timeout = MAX_INTERVAL, }; /* * It makes no sense to go into suspend while the watchdog is running. * Depending on the memory size, the watchdog might trigger, while we * are still saving the memory. */ static int wdt_suspend(void) { if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status)) { pr_err("Linux cannot be suspended while the watchdog is in use\n"); return notifier_from_errno(-EBUSY); } return NOTIFY_DONE; } static int wdt_resume(void) { clear_bit(DIAG_WDOG_BUSY, &wdt_status); return NOTIFY_DONE; } static int wdt_power_event(struct notifier_block *this, unsigned long event, void *ptr) { switch (event) { case PM_POST_HIBERNATION: case PM_POST_SUSPEND: return wdt_resume(); case PM_HIBERNATION_PREPARE: case PM_SUSPEND_PREPARE: return wdt_suspend(); default: return NOTIFY_DONE; } } static struct notifier_block wdt_power_notifier = { .notifier_call = wdt_power_event, }; static int __init diag288_init(void) { int ret; char ebc_begin[] = { 194, 197, 199, 201, 213 }; watchdog_set_nowayout(&wdt_dev, nowayout_info); if (MACHINE_IS_VM) { if (__diag288_vm(WDT_FUNC_INIT, 15, ebc_begin, sizeof(ebc_begin)) != 0) { pr_err("The watchdog cannot be initialized\n"); return -EINVAL; } } else { if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) { pr_err("The watchdog cannot be initialized\n"); return -EINVAL; } } if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) { pr_err("The watchdog cannot be deactivated\n"); return -EINVAL; } ret = register_pm_notifier(&wdt_power_notifier); if (ret) return ret; ret = watchdog_register_device(&wdt_dev); if (ret) unregister_pm_notifier(&wdt_power_notifier); return ret; } static void __exit diag288_exit(void) { watchdog_unregister_device(&wdt_dev); unregister_pm_notifier(&wdt_power_notifier); } module_init(diag288_init); module_exit(diag288_exit); 480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net/8021q/Kconfig')