/* * Renesas Emma Mobile 8250 driver * * Copyright (C) 2012 Magnus Damm * * 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 * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include #include "8250.h" #define UART_DLL_EM 9 #define UART_DLM_EM 10 struct serial8250_em_priv { struct clk *sclk; int line; }; static void serial8250_em_serial_out(struct uart_port *p, int offset, int value) { switch (offset) { case UART_TX: /* TX @ 0x00 */ writeb(value, p->membase); break; case UART_FCR: /* FCR @ 0x0c (+1) */ case UART_LCR: /* LCR @ 0x10 (+1) */ case UART_MCR: /* MCR @ 0x14 (+1) */ case UART_SCR: /* SCR @ 0x20 (+1) */ writel(value, p->membase + ((offset + 1) << 2)); break; case UART_IER: /* IER @ 0x04 */ value &= 0x0f; /* only 4 valid bits - not Xscale */ /* fall-through */ case UART_DLL_EM: /* DLL @ 0x24 (+9) */ case UART_DLM_EM: /* DLM @ 0x28 (+9) */ writel(value, p->membase + (offset << 2)); } } static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset) { switch (offset) { case UART_RX: /* RX @ 0x00 */ return readb(p->membase); case UART_MCR: /* MCR @ 0x14 (+1) */ case UART_LSR: /* LSR @ 0x18 (+1) */ case UART_MSR: /* MSR @ 0x1c (+1) */ case UART_SCR: /* SCR @ 0x20 (+1) */ return readl(p->membase + ((offset + 1) << 2)); case UART_IER: /* IER @ 0x04 */ case UART_IIR: /* IIR @ 0x08 */ case UART_DLL_EM: /* DLL @ 0x24 (+9) */ case UART_DLM_EM: /* DLM @ 0x28 (+9) */ return readl(p->membase + (offset << 2)); } return 0; } static int serial8250_em_serial_dl_read(struct uart_8250_port *up) { return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8; } static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value) { serial_out(up, UART_DLL_EM, value & 0xff); serial_out(up, UART_DLM_EM, value >> 8 & 0xff); } static int serial8250_em_probe(struct platform_device *pdev) { struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); struct serial8250_em_priv *priv; struct uart_8250_port up; int ret; if (!regs || !irq) { dev_err(&pdev->dev, "missing registers or irq\n"); return -EINVAL; } priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->sclk = devm_clk_get(&pdev->dev, "sclk"); if (IS_ERR(priv->sclk)) { dev_err(&pdev->dev, "unable to get clock\n"); return PTR_ERR(priv->sclk); } memset(&up, 0, sizeof(up)); up.port.mapbase = regs->start; up.port.irq = irq->start; up.port.type = PORT_UNKNOWN; up.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP; up.port.dev = &pdev->dev; up.port.private_data = priv; clk_prepare_enable(priv->sclk); up.port.uartclk = clk_get_rate(priv->sclk); up.port.iotype = UPIO_MEM32; up.port.serial_in = serial8250_em_serial_in; up.port.serial_out = serial8250_em_serial_out; up.dl_read = serial8250_em_serial_dl_read; up.dl_write = serial8250_em_serial_dl_write; ret = serial8250_register_8250_port(&up); if (ret < 0) { dev_err(&pdev->dev, "unable to register 8250 port\n"); clk_disable_unprepare(priv->sclk); return ret; } priv->line = ret; platform_set_drvdata(pdev, priv); return 0; } static int serial8250_em_remove(struct platform_device *pdev) { struct serial8250_em_priv *priv = platform_get_drvdata(pdev); serial8250_unregister_port(priv->line); clk_disable_unprepare(priv->sclk); return 0; } static const struct of_device_id serial8250_em_dt_ids[] = { { .compatible = "renesas,em-uart", }, {}, }; MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids); static struct platform_driver serial8250_em_platform_driver = { .driver = { .name = "serial8250-em", .of_match_table = serial8250_em_dt_ids, }, .probe = serial8250_em_probe, .remove = serial8250_em_remove, }; module_platform_driver(serial8250_em_platform_driver); MODULE_AUTHOR("Magnus Damm"); MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver"); MODULE_LICENSE("GPL v2"); r> commit39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch) tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /include/net/gue.h parent2c5d9555d6d937966d79d4c6529a5f7b9206e405 (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 'include/net/gue.h')