/* * Watchdog driver for Renesas WDT watchdog * * Copyright (C) 2015-16 Wolfram Sang, Sang Engineering * Copyright (C) 2015-16 Renesas Electronics Corporation * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published by * the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #define RWTCNT 0 #define RWTCSRA 4 #define RWTCSRA_WOVF BIT(4) #define RWTCSRA_WRFLG BIT(5) #define RWTCSRA_TME BIT(7) #define RWDT_DEFAULT_TIMEOUT 60U static const unsigned int clk_divs[] = { 1, 4, 16, 32, 64, 128, 1024 }; 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) ")"); struct rwdt_priv { void __iomem *base; struct watchdog_device wdev; struct clk *clk; unsigned int clks_per_sec; u8 cks; }; static void rwdt_write(struct rwdt_priv *priv, u32 val, unsigned int reg) { if (reg == RWTCNT) val |= 0x5a5a0000; else val |= 0xa5a5a500; writel_relaxed(val, priv->base + reg); } static int rwdt_init_timeout(struct watchdog_device *wdev) { struct rwdt_priv *priv = watchdog_get_drvdata(wdev); rwdt_write(priv, 65536 - wdev->timeout * priv->clks_per_sec, RWTCNT); return 0; } static int rwdt_start(struct watchdog_device *wdev) { struct rwdt_priv *priv = watchdog_get_drvdata(wdev); clk_prepare_enable(priv->clk); rwdt_write(priv, priv->cks, RWTCSRA); rwdt_init_timeout(wdev); while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG) cpu_relax(); rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA); return 0; } static int rwdt_stop(struct watchdog_device *wdev) { struct rwdt_priv *priv = watchdog_get_drvdata(wdev); rwdt_write(priv, priv->cks, RWTCSRA); clk_disable_unprepare(priv->clk); return 0; } static unsigned int rwdt_get_timeleft(struct watchdog_device *wdev) { struct rwdt_priv *priv = watchdog_get_drvdata(wdev); u16 val = readw_relaxed(priv->base + RWTCNT); return DIV_ROUND_CLOSEST(65536 - val, priv->clks_per_sec); } static const struct watchdog_info rwdt_ident = { .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, .identity = "Renesas WDT Watchdog", }; static const struct watchdog_ops rwdt_ops = { .owner = THIS_MODULE, .start = rwdt_start, .stop = rwdt_stop, .ping = rwdt_init_timeout, .get_timeleft = rwdt_get_timeleft, }; static int rwdt_probe(struct platform_device *pdev) { struct rwdt_priv *priv; struct resource *res; unsigned long rate; unsigned int clks_per_sec; int ret, i; priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); priv->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(priv->base)) return PTR_ERR(priv->base); priv->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(priv->clk)) return PTR_ERR(priv->clk); rate = clk_get_rate(priv->clk); if (!rate) return -ENOENT; for (i = ARRAY_SIZE(clk_divs) - 1; i >= 0; i--) { clks_per_sec = DIV_ROUND_UP(rate, clk_divs[i]); if (clks_per_sec) { priv->clks_per_sec = clks_per_sec; priv->cks = i; break; } } if (!clks_per_sec) { dev_err(&pdev->dev, "Can't find suitable clock divider\n"); return -ERANGE; } pm_runtime_enable(&pdev->dev); pm_runtime_get_sync(&pdev->dev); priv->wdev.info = &rwdt_ident, priv->wdev.ops = &rwdt_ops, priv->wdev.parent = &pdev->dev; priv->wdev.min_timeout = 1; priv->wdev.max_timeout = 65536 / clks_per_sec; priv->wdev.timeout = min(priv->wdev.max_timeout, RWDT_DEFAULT_TIMEOUT); platform_set_drvdata(pdev, priv); watchdog_set_drvdata(&priv->wdev, priv); watchdog_set_nowayout(&priv->wdev, nowayout); /* This overrides the default timeout only if DT configuration was found */ ret = watchdog_init_timeout(&priv->wdev, 0, &pdev->dev); if (ret) dev_warn(&pdev->dev, "Specified timeout value invalid, using default\n"); ret = watchdog_register_device(&priv->wdev); if (ret < 0) { pm_runtime_put(&pdev->dev); pm_runtime_disable(&pdev->dev); return ret; } return 0; } static int rwdt_remove(struct platform_device *pdev) { struct rwdt_priv *priv = platform_get_drvdata(pdev); watchdog_unregister_device(&priv->wdev); pm_runtime_put(&pdev->dev); pm_runtime_disable(&pdev->dev); return 0; } /* * This driver does also fit for R-Car Gen2 (r8a779[0-4]) WDT. However, for SMP * to work there, one also needs a RESET (RST) driver which does not exist yet * due to HW issues. This needs to be solved before adding compatibles here. */ static const struct of_device_id rwdt_ids[] = { { .compatible = "renesas,rcar-gen3-wdt", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, rwdt_ids); static struct platform_driver rwdt_driver = { .driver = { .name = "renesas_wdt", .of_match_table = rwdt_ids, }, .probe = rwdt_probe, .remove = rwdt_remove, }; module_platform_driver(rwdt_driver); MODULE_DESCRIPTION("Renesas WDT Watchdog Driver"); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Wolfram Sang "); /cgit.cgi/linux/net-next.git/diff/net/can?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e&id2=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>diff)
drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()
I've seen this trigger twice now, where the i915_gem_object_to_ggtt() call in intel_unpin_fb_obj() returns NULL, resulting in an oops immediately afterwards as the (inlined) call to i915_vma_unpin_fence() tries to dereference it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting 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 'net/can')