From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ... --- drivers/char/hangcheck-timer.c | 179 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 179 insertions(+) create mode 100644 drivers/char/hangcheck-timer.c (limited to 'drivers/char/hangcheck-timer.c') 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 + */ + +/* + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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); -- cgit v1.3.1