/* drivers/char/watchdog/scx200_wdt.c National Semiconductor SCx200 Watchdog support Copyright (c) 2001,2002 Christer Weinigel Some code taken from: National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver (c) Copyright 2002 Zwane Mwaikambo This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The author(s) of this software shall not be held liable for damages of any nature resulting due to the use of this software. This software is provided AS-IS with no warranties. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #define DEBUG MODULE_AUTHOR("Christer Weinigel "); MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver"); MODULE_LICENSE("GPL"); static int margin = 60; /* in seconds */ module_param(margin, int, 0); MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); static u16 wdto_restart; static char expect_close; static unsigned long open_lock; static DEFINE_SPINLOCK(scx_lock); /* Bits of the WDCNFG register */ #define W_ENABLE 0x00fa /* Enable watchdog */ #define W_DISABLE 0x0000 /* Disable watchdog */ /* The scaling factor for the timer, this depends on the value of W_ENABLE */ #define W_SCALE (32768/1024) static void scx200_wdt_ping(void) { spin_lock(&scx_lock); outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO); spin_unlock(&scx_lock); } static void scx200_wdt_update_margin(void) { pr_info("timer margin %d seconds\n", margin); wdto_restart = margin * W_SCALE; } static void scx200_wdt_enable(void) { pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart); spin_lock(&scx_lock); outw(0, scx200_cb_base + SCx200_WDT_WDTO); outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG); spin_unlock(&scx_lock); scx200_wdt_ping(); } static void scx200_wdt_disable(void) { pr_debug("disabling watchdog timer\n"); spin_lock(&scx_lock); outw(0, scx200_cb_base + SCx200_WDT_WDTO); outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG); spin_unlock(&scx_lock); } static int scx200_wdt_open(struct inode *inode, struct file *file) { /* only allow one at a time */ if (test_and_set_bit(0, &open_lock)) return -EBUSY; scx200_wdt_enable(); return nonseekable_open(inode, file); } static int scx200_wdt_release(struct inode *inode, struct file *file) { if (expect_close != 42) pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n"); else if (!nowayout) scx200_wdt_disable(); expect_close = 0; clear_bit(0, &open_lock); return 0; } static int scx200_wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_HALT || code == SYS_POWER_OFF) if (!nowayout) scx200_wdt_disable(); return NOTIFY_DONE; } static struct notifier_block scx200_wdt_notifier = { .notifier_call = scx200_wdt_notify_sys, }; static ssize_t scx200_wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { /* check for a magic close character */ if (len) { size_t i; scx200_wdt_ping(); expect_close = 0; for (i = 0; i < len; ++i) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') expect_close = 42; } return len; } return 0; } static long scx200_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; static const struct watchdog_info ident = { .identity = "NatSemi SCx200 Watchdog", .firmware_version = 1, .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; int new_margin; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &ident, sizeof(ident))) return -EFAULT; return 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: if (put_user(0, p)) return -EFAULT; return 0; case WDIOC_KEEPALIVE: scx200_wdt_ping(); return 0; case WDIOC_SETTIMEOUT: if (get_user(new_margin, p)) return -EFAULT; if (new_margin < 1) return -EINVAL; margin = new_margin; scx200_wdt_update_margin(); scx200_wdt_ping(); case WDIOC_GETTIMEOUT: if (put_user(margin, p)) return -EFAULT; return 0; default: return -ENOTTY; } } static const struct file_operations scx200_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = scx200_wdt_write, .unlocked_ioctl = scx200_wdt_ioctl, .open = scx200_wdt_open, .release = scx200_wdt_release, }; static struct miscdevice scx200_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &scx200_wdt_fops, }; static int __init scx200_wdt_init(void) { int r; pr_debug("NatSemi SCx200 Watchdog Driver\n"); /* check that we have found the configuration block */ if (!scx200_cb_present()) return -ENODEV; if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET, SCx200_WDT_SIZE, "NatSemi SCx200 Watchdog")) { pr_warn("watchdog I/O region busy\n"); return -EBUSY; } scx200_wdt_update_margin(); scx200_wdt_disable(); r = register_reboot_notifier(&scx200_wdt_notifier); if (r) { pr_err("unable to register reboot notifier\n"); release_region(scx200_cb_base + SCx200_WDT_OFFSET, SCx200_WDT_SIZE); return r; } r = misc_register(&scx200_wdt_miscdev); if (r) { unregister_reboot_notifier(&scx200_wdt_notifier); release_region(scx200_cb_base + SCx200_WDT_OFFSET, SCx200_WDT_SIZE); return r; } return 0; } static void __exit scx200_wdt_cleanup(void) { misc_deregister(&scx200_wdt_miscdev); unregister_reboot_notifier(&scx200_wdt_notifier); release_region(scx200_cb_base + SCx200_WDT_OFFSET, SCx200_WDT_SIZE); } module_init(scx200_wdt_init); module_exit(scx200_wdt_cleanup); /* Local variables: compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules" c-basic-offset: 8 End: */ down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 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 'sound/firewire')