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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
commitcf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch)
tree757a3d280760c654767631cab5ad8af2d86d1848 /drivers/char/hangcheck-timer.c
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Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij: "Core changes: - Use the non-blocking mux_state_try_select() in the generic MUX pin control back-end - Free pin maps on pinctrl_generic_to_map() failure in the core helpers New hardware pin control: - Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC (this is for the low power audio, LPASS = Low Power Audio SubSystem portions) - Upboard support on top of the Intel pin controller - Apple T6030 and T6031 support (just compatible strings) - Samsung Exynos 8855 SoC - Mediatek MT6858 SoC - Rockchip RK3308B and RV1106 SoCs - Airoha EN7523 and AN7563 SoCs Improvements: - Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable - Qualcomm improvements on top of the Qualcomm PDC (power domain controller) irqchip improvements from tglx:s tree - Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups - The NPCM8xx driver has been put into shape fixing many pin and group definitions - Some non-urgent Tegra 264 pin assignments are fixed up - Some non-urgent fixups to Airoha AN7581 and AN7583 registers and pin assignments, missing features etc" * tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits) dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema pinctrl: meson: sync some modify from A4 pinctrl: meson: a4: Add input enable pin configuration pinctrl: realtek: rtd1625: remove unused group name spdif_sel pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13 dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema Revert "Merge branch 'ib-rsk7204' into devel" pinctrl: rockchip: Add RV1106 pinctrl support dt-bindings: pinctrl: rockchip: Add RV1106 compatible pinctrl: rockchip: Decode drive strength in the get function pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable pinctrl: airoha: add support of an7563 SoC dt-bindings: pinctrl: airoha: add support of an7563 pin controller pinctrl: airoha: try to find chip scu node by phandle first pinctrl: airoha: add support of en7523 SoC dt-bindings: pinctrl: airoha: add support of en7523 pin controller pinctrl: airoha: an7583: add support for olt pinmux pinctrl: airoha: an7583: add support for pon_alt pinmux pinctrl: airoha: an7583: add support for npu_uart pinmux dt-bindings: pinctrl: airoha: an7583: add missed features ...
Diffstat (limited to 'drivers/char/hangcheck-timer.c')
-rw-r--r--drivers/char/hangcheck-timer.c179
1 files changed, 179 insertions, 0 deletions
diff --git a/drivers/char/hangcheck-timer.c b/drivers/char/hangcheck-timer.c
new file mode 100644
index 000000000..231cbf7b3
--- /dev/null
+++ b/drivers/char/hangcheck-timer.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * hangcheck-timer.c
+ *
+ * Driver for a little io fencing timer.
+ *
+ * Copyright (C) 2002, 2003 Oracle. All rights reserved.
+ *
+ * Author: Joel Becker <joel.becker@oracle.com>
+ */
+
+/*
+ * The hangcheck-timer driver uses the TSC to catch delays that
+ * jiffies does not notice. A timer is set. When the timer fires, it
+ * checks whether it was delayed and if that delay exceeds a given
+ * margin of error. The hangcheck_tick module parameter takes the timer
+ * duration in seconds. The hangcheck_margin parameter defines the
+ * margin of error, in seconds. The defaults are 60 seconds for the
+ * timer and 180 seconds for the margin of error. IOW, a timer is set
+ * for 60 seconds. When the timer fires, the callback checks the
+ * actual duration that the timer waited. If the duration exceeds the
+ * allotted time and margin (here 60 + 180, or 240 seconds), the machine
+ * is restarted. A healthy machine will have the duration match the
+ * expected timeout very closely.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <linux/sysrq.h>
+#include <linux/timer.h>
+#include <linux/hrtimer.h>
+
+#define VERSION_STR "0.9.1"
+
+#define DEFAULT_IOFENCE_MARGIN 60 /* Default fudge factor, in seconds */
+#define DEFAULT_IOFENCE_TICK 180 /* Default timer timeout, in seconds */
+
+static int hangcheck_tick = DEFAULT_IOFENCE_TICK;
+static int hangcheck_margin = DEFAULT_IOFENCE_MARGIN;
+static int hangcheck_reboot; /* Defaults to not reboot */
+static int hangcheck_dump_tasks; /* Defaults to not dumping SysRQ T */
+
+/* options - modular */
+module_param(hangcheck_tick, int, 0);
+MODULE_PARM_DESC(hangcheck_tick, "Timer delay.");
+module_param(hangcheck_margin, int, 0);
+MODULE_PARM_DESC(hangcheck_margin, "If the hangcheck timer has been delayed more than hangcheck_margin seconds, the driver will fire.");
+module_param(hangcheck_reboot, int, 0);
+MODULE_PARM_DESC(hangcheck_reboot, "If nonzero, the machine will reboot when the timer margin is exceeded.");
+module_param(hangcheck_dump_tasks, int, 0);
+MODULE_PARM_DESC(hangcheck_dump_tasks, "If nonzero, the machine will dump the system task state when the timer margin is exceeded.");
+
+MODULE_AUTHOR("Oracle");
+MODULE_DESCRIPTION("Hangcheck-timer detects when the system has gone out to lunch past a certain margin.");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(VERSION_STR);
+
+/* options - nonmodular */
+#ifndef MODULE
+
+static int __init hangcheck_parse_tick(char *str)
+{
+ int par;
+
+ if (get_option(&str, &par))
+ hangcheck_tick = par;
+ return 1;
+}
+
+static int __init hangcheck_parse_margin(char *str)
+{
+ int par;
+
+ if (get_option(&str, &par))
+ hangcheck_margin = par;
+ return 1;
+}
+
+static int __init hangcheck_parse_reboot(char *str)
+{
+ int par;
+
+ if (get_option(&str, &par))
+ hangcheck_reboot = par;
+ return 1;
+}
+
+static int __init hangcheck_parse_dump_tasks(char *str)
+{
+ int par;
+
+ if (get_option(&str, &par))
+ hangcheck_dump_tasks = par;
+ return 1;
+}
+
+__setup("hcheck_tick", hangcheck_parse_tick);
+__setup("hcheck_margin", hangcheck_parse_margin);
+__setup("hcheck_reboot", hangcheck_parse_reboot);
+__setup("hcheck_dump_tasks", hangcheck_parse_dump_tasks);
+#endif /* not MODULE */
+
+#define TIMER_FREQ 1000000000ULL
+
+/* Last time scheduled */
+static unsigned long long hangcheck_tsc, hangcheck_tsc_margin;
+
+static void hangcheck_fire(struct timer_list *);
+
+static DEFINE_TIMER(hangcheck_ticktock, hangcheck_fire);
+
+static void hangcheck_fire(struct timer_list *unused)
+{
+ unsigned long long cur_tsc, tsc_diff;
+
+ cur_tsc = ktime_get_ns();
+
+ if (cur_tsc > hangcheck_tsc)
+ tsc_diff = cur_tsc - hangcheck_tsc;
+ else
+ tsc_diff = (cur_tsc + (~0ULL - hangcheck_tsc)); /* or something */
+
+ if (tsc_diff > hangcheck_tsc_margin) {
+ if (hangcheck_dump_tasks) {
+ pr_crit("Hangcheck: Task state:\n");
+#ifdef CONFIG_MAGIC_SYSRQ
+ handle_sysrq('t');
+#endif /* CONFIG_MAGIC_SYSRQ */
+ }
+ if (hangcheck_reboot) {
+ pr_crit("Hangcheck: hangcheck is restarting the machine.\n");
+ emergency_restart();
+ } else {
+ pr_crit("Hangcheck: hangcheck value past margin!\n");
+ }
+ }
+#if 0
+ /*
+ * Enable to investigate delays in detail
+ */
+ pr_debug("Hangcheck: called %lld ns since last time (%lld ns overshoot)\n",
+ tsc_diff, tsc_diff - hangcheck_tick*TIMER_FREQ);
+#endif
+ mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
+ hangcheck_tsc = ktime_get_ns();
+}
+
+
+static int __init hangcheck_init(void)
+{
+ pr_debug("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
+ VERSION_STR, hangcheck_tick, hangcheck_margin);
+ hangcheck_tsc_margin =
+ (unsigned long long)hangcheck_margin + hangcheck_tick;
+ hangcheck_tsc_margin *= TIMER_FREQ;
+
+ hangcheck_tsc = ktime_get_ns();
+ mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
+
+ return 0;
+}
+
+
+static void __exit hangcheck_exit(void)
+{
+ timer_delete_sync(&hangcheck_ticktock);
+ pr_debug("Hangcheck: Stopped hangcheck timer.\n");
+}
+
+module_init(hangcheck_init);
+module_exit(hangcheck_exit);