Thomas Gleixner | 35728b8 | 2018-10-31 19:21:09 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 2 | /* |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 3 | * This file contains the base functions to manage periodic tick |
| 4 | * related events. |
| 5 | * |
| 6 | * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> |
| 7 | * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar |
| 8 | * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 9 | */ |
| 10 | #include <linux/cpu.h> |
| 11 | #include <linux/err.h> |
| 12 | #include <linux/hrtimer.h> |
Russell King | d7b9068 | 2008-04-17 07:46:24 +0200 | [diff] [blame] | 13 | #include <linux/interrupt.h> |
Chunyan Zhang | 5167c50 | 2020-01-10 16:39:02 +0800 | [diff] [blame] | 14 | #include <linux/nmi.h> |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 15 | #include <linux/percpu.h> |
| 16 | #include <linux/profile.h> |
| 17 | #include <linux/sched.h> |
Thomas Gleixner | ccf33d6 | 2013-04-25 20:31:49 +0000 | [diff] [blame] | 18 | #include <linux/module.h> |
Rafael J. Wysocki | 75e0678 | 2015-05-10 01:23:35 +0200 | [diff] [blame] | 19 | #include <trace/events/power.h> |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 20 | |
Russell King | d7b9068 | 2008-04-17 07:46:24 +0200 | [diff] [blame] | 21 | #include <asm/irq_regs.h> |
| 22 | |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 23 | #include "tick-internal.h" |
| 24 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 25 | /* |
| 26 | * Tick devices |
| 27 | */ |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 28 | DEFINE_PER_CPU(struct tick_device, tick_cpu_device); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 29 | /* |
Thomas Gleixner | c398960 | 2020-11-17 14:19:44 +0100 | [diff] [blame] | 30 | * Tick next event: keeps track of the tick time. It's updated by the |
| 31 | * CPU which handles the tick and protected by jiffies_lock. There is |
| 32 | * no requirement to write hold the jiffies seqcount for it. |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 33 | */ |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 34 | ktime_t tick_next_period; |
Andrew Morton | 050ded1 | 2013-11-15 14:15:33 -0800 | [diff] [blame] | 35 | |
| 36 | /* |
| 37 | * tick_do_timer_cpu is a timer core internal variable which holds the CPU NR |
| 38 | * which is responsible for calling do_timer(), i.e. the timekeeping stuff. This |
| 39 | * variable has two functions: |
| 40 | * |
| 41 | * 1) Prevent a thundering herd issue of a gazillion of CPUs trying to grab the |
| 42 | * timekeeping lock all at once. Only the CPU which is assigned to do the |
| 43 | * update is handling it. |
| 44 | * |
| 45 | * 2) Hand off the duty in the NOHZ idle case by setting the value to |
| 46 | * TICK_DO_TIMER_NONE, i.e. a non existing CPU. So the next cpu which looks |
| 47 | * at it will take over and keep the time keeping alive. The handover |
| 48 | * procedure also covers cpu hotplug. |
| 49 | */ |
Thomas Gleixner | 6441402 | 2008-09-22 18:46:37 +0200 | [diff] [blame] | 50 | int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT; |
Nicholas Piggin | 08ae95f | 2019-04-11 13:34:48 +1000 | [diff] [blame] | 51 | #ifdef CONFIG_NO_HZ_FULL |
| 52 | /* |
| 53 | * tick_do_timer_boot_cpu indicates the boot CPU temporarily owns |
| 54 | * tick_do_timer_cpu and it should be taken over by an eligible secondary |
| 55 | * when one comes online. |
| 56 | */ |
| 57 | static int tick_do_timer_boot_cpu __read_mostly = -1; |
| 58 | #endif |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 59 | |
Ingo Molnar | 289f480 | 2007-02-16 01:28:15 -0800 | [diff] [blame] | 60 | /* |
| 61 | * Debugging: see timer_list.c |
| 62 | */ |
| 63 | struct tick_device *tick_get_device(int cpu) |
| 64 | { |
| 65 | return &per_cpu(tick_cpu_device, cpu); |
| 66 | } |
| 67 | |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 68 | /** |
| 69 | * tick_is_oneshot_available - check for a oneshot capable event device |
| 70 | */ |
| 71 | int tick_is_oneshot_available(void) |
| 72 | { |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 73 | struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 74 | |
Thomas Gleixner | 3a142a0 | 2011-02-25 22:34:23 +0100 | [diff] [blame] | 75 | if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT)) |
| 76 | return 0; |
| 77 | if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) |
| 78 | return 1; |
| 79 | return tick_broadcast_oneshot_available(); |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 80 | } |
| 81 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 82 | /* |
| 83 | * Periodic tick |
| 84 | */ |
| 85 | static void tick_periodic(int cpu) |
| 86 | { |
| 87 | if (tick_do_timer_cpu == cpu) { |
Thomas Gleixner | e5d4d17 | 2020-03-21 12:25:58 +0100 | [diff] [blame] | 88 | raw_spin_lock(&jiffies_lock); |
| 89 | write_seqcount_begin(&jiffies_seq); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 90 | |
| 91 | /* Keep track of the next tick event */ |
Thomas Gleixner | b996544 | 2020-11-17 14:19:49 +0100 | [diff] [blame] | 92 | tick_next_period = ktime_add_ns(tick_next_period, TICK_NSEC); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 93 | |
| 94 | do_timer(1); |
Thomas Gleixner | e5d4d17 | 2020-03-21 12:25:58 +0100 | [diff] [blame] | 95 | write_seqcount_end(&jiffies_seq); |
| 96 | raw_spin_unlock(&jiffies_lock); |
John Stultz | 47a1b796 | 2013-12-12 13:10:55 -0800 | [diff] [blame] | 97 | update_wall_time(); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 98 | } |
| 99 | |
| 100 | update_process_times(user_mode(get_irq_regs())); |
| 101 | profile_tick(CPU_PROFILING); |
| 102 | } |
| 103 | |
| 104 | /* |
| 105 | * Event handler for periodic ticks |
| 106 | */ |
| 107 | void tick_handle_periodic(struct clock_event_device *dev) |
| 108 | { |
| 109 | int cpu = smp_processor_id(); |
Viresh Kumar | b97f029 | 2014-03-25 13:56:23 +0530 | [diff] [blame] | 110 | ktime_t next = dev->next_event; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 111 | |
| 112 | tick_periodic(cpu); |
| 113 | |
Thomas Gleixner | c6eb3f7 | 2015-04-14 21:08:51 +0000 | [diff] [blame] | 114 | #if defined(CONFIG_HIGH_RES_TIMERS) || defined(CONFIG_NO_HZ_COMMON) |
| 115 | /* |
| 116 | * The cpu might have transitioned to HIGHRES or NOHZ mode via |
| 117 | * update_process_times() -> run_local_timers() -> |
| 118 | * hrtimer_run_queues(). |
| 119 | */ |
| 120 | if (dev->event_handler != tick_handle_periodic) |
| 121 | return; |
| 122 | #endif |
| 123 | |
Viresh Kumar | 472c4a9 | 2015-05-21 13:33:46 +0530 | [diff] [blame] | 124 | if (!clockevent_state_oneshot(dev)) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 125 | return; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 126 | for (;;) { |
Viresh Kumar | b97f029 | 2014-03-25 13:56:23 +0530 | [diff] [blame] | 127 | /* |
| 128 | * Setup the next period for devices, which do not have |
| 129 | * periodic mode: |
| 130 | */ |
Thomas Gleixner | b996544 | 2020-11-17 14:19:49 +0100 | [diff] [blame] | 131 | next = ktime_add_ns(next, TICK_NSEC); |
Viresh Kumar | b97f029 | 2014-03-25 13:56:23 +0530 | [diff] [blame] | 132 | |
Martin Schwidefsky | d174830 | 2011-08-23 15:29:42 +0200 | [diff] [blame] | 133 | if (!clockevents_program_event(dev, next, false)) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 134 | return; |
john stultz | 74a03b6 | 2009-05-01 13:10:25 -0700 | [diff] [blame] | 135 | /* |
| 136 | * Have to be careful here. If we're in oneshot mode, |
| 137 | * before we call tick_periodic() in a loop, we need |
| 138 | * to be sure we're using a real hardware clocksource. |
| 139 | * Otherwise we could get trapped in an infinite |
| 140 | * loop, as the tick_periodic() increments jiffies, |
Viresh Kumar | cacb3c7 | 2014-03-25 16:09:18 +0530 | [diff] [blame] | 141 | * which then will increment time, possibly causing |
john stultz | 74a03b6 | 2009-05-01 13:10:25 -0700 | [diff] [blame] | 142 | * the loop to trigger again and again. |
| 143 | */ |
| 144 | if (timekeeping_valid_for_hres()) |
| 145 | tick_periodic(cpu); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 146 | } |
| 147 | } |
| 148 | |
| 149 | /* |
| 150 | * Setup the device for a periodic tick |
| 151 | */ |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 152 | void tick_setup_periodic(struct clock_event_device *dev, int broadcast) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 153 | { |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 154 | tick_set_periodic_handler(dev, broadcast); |
| 155 | |
| 156 | /* Broadcast setup ? */ |
| 157 | if (!tick_device_is_functional(dev)) |
| 158 | return; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 159 | |
Thomas Gleixner | 27ce4cb4a | 2008-09-22 19:04:02 +0200 | [diff] [blame] | 160 | if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) && |
| 161 | !tick_broadcast_oneshot_active()) { |
Thomas Gleixner | d7eb231 | 2015-06-02 14:08:46 +0200 | [diff] [blame] | 162 | clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 163 | } else { |
Rasmus Villemoes | e1e41b6 | 2019-03-18 20:55:56 +0100 | [diff] [blame] | 164 | unsigned int seq; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 165 | ktime_t next; |
| 166 | |
| 167 | do { |
Thomas Gleixner | e5d4d17 | 2020-03-21 12:25:58 +0100 | [diff] [blame] | 168 | seq = read_seqcount_begin(&jiffies_seq); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 169 | next = tick_next_period; |
Thomas Gleixner | e5d4d17 | 2020-03-21 12:25:58 +0100 | [diff] [blame] | 170 | } while (read_seqcount_retry(&jiffies_seq, seq)); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 171 | |
Thomas Gleixner | d7eb231 | 2015-06-02 14:08:46 +0200 | [diff] [blame] | 172 | clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 173 | |
| 174 | for (;;) { |
Martin Schwidefsky | d174830 | 2011-08-23 15:29:42 +0200 | [diff] [blame] | 175 | if (!clockevents_program_event(dev, next, false)) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 176 | return; |
Thomas Gleixner | b996544 | 2020-11-17 14:19:49 +0100 | [diff] [blame] | 177 | next = ktime_add_ns(next, TICK_NSEC); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 178 | } |
| 179 | } |
| 180 | } |
| 181 | |
Nicholas Piggin | 08ae95f | 2019-04-11 13:34:48 +1000 | [diff] [blame] | 182 | #ifdef CONFIG_NO_HZ_FULL |
| 183 | static void giveup_do_timer(void *info) |
| 184 | { |
| 185 | int cpu = *(unsigned int *)info; |
| 186 | |
| 187 | WARN_ON(tick_do_timer_cpu != smp_processor_id()); |
| 188 | |
| 189 | tick_do_timer_cpu = cpu; |
| 190 | } |
| 191 | |
| 192 | static void tick_take_do_timer_from_boot(void) |
| 193 | { |
| 194 | int cpu = smp_processor_id(); |
| 195 | int from = tick_do_timer_boot_cpu; |
| 196 | |
| 197 | if (from >= 0 && from != cpu) |
| 198 | smp_call_function_single(from, giveup_do_timer, &cpu, 1); |
| 199 | } |
| 200 | #endif |
| 201 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 202 | /* |
| 203 | * Setup the tick device |
| 204 | */ |
| 205 | static void tick_setup_device(struct tick_device *td, |
| 206 | struct clock_event_device *newdev, int cpu, |
Rusty Russell | 0de2652 | 2008-12-13 21:20:26 +1030 | [diff] [blame] | 207 | const struct cpumask *cpumask) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 208 | { |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 209 | void (*handler)(struct clock_event_device *) = NULL; |
Thomas Gleixner | 8b0e195 | 2016-12-25 12:30:41 +0100 | [diff] [blame] | 210 | ktime_t next_event = 0; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 211 | |
| 212 | /* |
| 213 | * First device setup ? |
| 214 | */ |
| 215 | if (!td->evtdev) { |
| 216 | /* |
| 217 | * If no cpu took the do_timer update, assign it to |
| 218 | * this cpu: |
| 219 | */ |
Thomas Gleixner | 6441402 | 2008-09-22 18:46:37 +0200 | [diff] [blame] | 220 | if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) { |
Nicholas Piggin | 08ae95f | 2019-04-11 13:34:48 +1000 | [diff] [blame] | 221 | tick_do_timer_cpu = cpu; |
| 222 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 223 | tick_next_period = ktime_get(); |
Nicholas Piggin | 08ae95f | 2019-04-11 13:34:48 +1000 | [diff] [blame] | 224 | #ifdef CONFIG_NO_HZ_FULL |
| 225 | /* |
| 226 | * The boot CPU may be nohz_full, in which case set |
| 227 | * tick_do_timer_boot_cpu so the first housekeeping |
| 228 | * secondary that comes up will take do_timer from |
| 229 | * us. |
| 230 | */ |
| 231 | if (tick_nohz_full_cpu(cpu)) |
| 232 | tick_do_timer_boot_cpu = cpu; |
| 233 | |
| 234 | } else if (tick_do_timer_boot_cpu != -1 && |
| 235 | !tick_nohz_full_cpu(cpu)) { |
| 236 | tick_take_do_timer_from_boot(); |
| 237 | tick_do_timer_boot_cpu = -1; |
| 238 | WARN_ON(tick_do_timer_cpu != cpu); |
| 239 | #endif |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 240 | } |
| 241 | |
| 242 | /* |
| 243 | * Startup in periodic mode first. |
| 244 | */ |
| 245 | td->mode = TICKDEV_MODE_PERIODIC; |
| 246 | } else { |
| 247 | handler = td->evtdev->event_handler; |
| 248 | next_event = td->evtdev->next_event; |
Venkatesh Pallipadi | 7c1e768 | 2008-09-03 21:36:50 +0000 | [diff] [blame] | 249 | td->evtdev->event_handler = clockevents_handle_noop; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 250 | } |
| 251 | |
| 252 | td->evtdev = newdev; |
| 253 | |
| 254 | /* |
| 255 | * When the device is not per cpu, pin the interrupt to the |
| 256 | * current cpu: |
| 257 | */ |
Rusty Russell | 320ab2b | 2008-12-13 21:20:26 +1030 | [diff] [blame] | 258 | if (!cpumask_equal(newdev->cpumask, cpumask)) |
Rusty Russell | 0de2652 | 2008-12-13 21:20:26 +1030 | [diff] [blame] | 259 | irq_set_affinity(newdev->irq, cpumask); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 260 | |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 261 | /* |
| 262 | * When global broadcasting is active, check if the current |
| 263 | * device is registered as a placeholder for broadcast mode. |
| 264 | * This allows us to handle this x86 misfeature in a generic |
Thomas Gleixner | 07bd117 | 2013-07-01 22:14:10 +0200 | [diff] [blame] | 265 | * way. This function also returns !=0 when we keep the |
| 266 | * current active broadcast state for this CPU. |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 267 | */ |
| 268 | if (tick_device_uses_broadcast(newdev, cpu)) |
| 269 | return; |
| 270 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 271 | if (td->mode == TICKDEV_MODE_PERIODIC) |
| 272 | tick_setup_periodic(newdev, 0); |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 273 | else |
| 274 | tick_setup_oneshot(newdev, handler, next_event); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 275 | } |
| 276 | |
Thomas Gleixner | 03e13cf | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 277 | void tick_install_replacement(struct clock_event_device *newdev) |
| 278 | { |
Christoph Lameter | 22127e9 | 2014-08-17 12:30:25 -0500 | [diff] [blame] | 279 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
Thomas Gleixner | 03e13cf | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 280 | int cpu = smp_processor_id(); |
| 281 | |
| 282 | clockevents_exchange_device(td->evtdev, newdev); |
| 283 | tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); |
| 284 | if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) |
| 285 | tick_oneshot_notify(); |
| 286 | } |
| 287 | |
Thomas Gleixner | 45cb8e0 | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 288 | static bool tick_check_percpu(struct clock_event_device *curdev, |
| 289 | struct clock_event_device *newdev, int cpu) |
| 290 | { |
| 291 | if (!cpumask_test_cpu(cpu, newdev->cpumask)) |
| 292 | return false; |
| 293 | if (cpumask_equal(newdev->cpumask, cpumask_of(cpu))) |
| 294 | return true; |
| 295 | /* Check if irq affinity can be set */ |
| 296 | if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq)) |
| 297 | return false; |
| 298 | /* Prefer an existing cpu local device */ |
| 299 | if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu))) |
| 300 | return false; |
| 301 | return true; |
| 302 | } |
| 303 | |
| 304 | static bool tick_check_preferred(struct clock_event_device *curdev, |
| 305 | struct clock_event_device *newdev) |
| 306 | { |
| 307 | /* Prefer oneshot capable device */ |
| 308 | if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) { |
| 309 | if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT)) |
| 310 | return false; |
| 311 | if (tick_oneshot_mode_active()) |
| 312 | return false; |
| 313 | } |
| 314 | |
Stephen Boyd | 70e5975 | 2013-06-13 11:39:50 -0700 | [diff] [blame] | 315 | /* |
| 316 | * Use the higher rated one, but prefer a CPU local device with a lower |
| 317 | * rating than a non-CPU local device |
| 318 | */ |
| 319 | return !curdev || |
| 320 | newdev->rating > curdev->rating || |
Sudeep Holla | 5b5ccbc | 2018-07-09 16:45:35 +0100 | [diff] [blame] | 321 | !cpumask_equal(curdev->cpumask, newdev->cpumask); |
Thomas Gleixner | 45cb8e0 | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 322 | } |
| 323 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 324 | /* |
Thomas Gleixner | 03e13cf | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 325 | * Check whether the new device is a better fit than curdev. curdev |
| 326 | * can be NULL ! |
| 327 | */ |
| 328 | bool tick_check_replacement(struct clock_event_device *curdev, |
| 329 | struct clock_event_device *newdev) |
| 330 | { |
Viresh Kumar | 521c429 | 2014-04-15 10:54:37 +0530 | [diff] [blame] | 331 | if (!tick_check_percpu(curdev, newdev, smp_processor_id())) |
Thomas Gleixner | 03e13cf | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 332 | return false; |
| 333 | |
| 334 | return tick_check_preferred(curdev, newdev); |
| 335 | } |
| 336 | |
| 337 | /* |
Thomas Gleixner | 7126cac | 2013-04-25 20:31:48 +0000 | [diff] [blame] | 338 | * Check, if the new registered device should be used. Called with |
| 339 | * clockevents_lock held and interrupts disabled. |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 340 | */ |
Thomas Gleixner | 7172a286 | 2013-04-25 20:31:47 +0000 | [diff] [blame] | 341 | void tick_check_new_device(struct clock_event_device *newdev) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 342 | { |
| 343 | struct clock_event_device *curdev; |
| 344 | struct tick_device *td; |
Thomas Gleixner | 7172a286 | 2013-04-25 20:31:47 +0000 | [diff] [blame] | 345 | int cpu; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 346 | |
| 347 | cpu = smp_processor_id(); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 348 | td = &per_cpu(tick_cpu_device, cpu); |
| 349 | curdev = td->evtdev; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 350 | |
Wang Wensheng | d7840aa | 2021-03-26 02:23:28 +0000 | [diff] [blame] | 351 | if (!tick_check_replacement(curdev, newdev)) |
Thomas Gleixner | 45cb8e0 | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 352 | goto out_bc; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 353 | |
Thomas Gleixner | ccf33d6 | 2013-04-25 20:31:49 +0000 | [diff] [blame] | 354 | if (!try_module_get(newdev->owner)) |
| 355 | return; |
| 356 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 357 | /* |
| 358 | * Replace the eventually existing device by the new |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 359 | * device. If the current device is the broadcast device, do |
| 360 | * not give it back to the clockevents layer ! |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 361 | */ |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 362 | if (tick_is_broadcast_device(curdev)) { |
Thomas Gleixner | 2344abb | 2008-09-16 11:32:50 -0700 | [diff] [blame] | 363 | clockevents_shutdown(curdev); |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 364 | curdev = NULL; |
| 365 | } |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 366 | clockevents_exchange_device(curdev, newdev); |
Rusty Russell | 6b95482 | 2009-01-01 10:12:25 +1030 | [diff] [blame] | 367 | tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 368 | if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) |
| 369 | tick_oneshot_notify(); |
Thomas Gleixner | 7172a286 | 2013-04-25 20:31:47 +0000 | [diff] [blame] | 370 | return; |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 371 | |
| 372 | out_bc: |
| 373 | /* |
| 374 | * Can the new device be used as a broadcast device ? |
| 375 | */ |
Will Deacon | c94a853 | 2021-05-24 23:18:16 +0100 | [diff] [blame] | 376 | tick_install_broadcast_device(newdev, cpu); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 377 | } |
| 378 | |
Thomas Gleixner | f32dd11 | 2015-07-07 16:29:38 +0200 | [diff] [blame] | 379 | /** |
| 380 | * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode |
| 381 | * @state: The target state (enter/exit) |
| 382 | * |
| 383 | * The system enters/leaves a state, where affected devices might stop |
| 384 | * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups. |
| 385 | * |
| 386 | * Called with interrupts disabled, so clockevents_lock is not |
| 387 | * required here because the local clock event device cannot go away |
| 388 | * under us. |
| 389 | */ |
| 390 | int tick_broadcast_oneshot_control(enum tick_broadcast_state state) |
| 391 | { |
| 392 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
| 393 | |
| 394 | if (!(td->evtdev->features & CLOCK_EVT_FEAT_C3STOP)) |
| 395 | return 0; |
| 396 | |
| 397 | return __tick_broadcast_oneshot_control(state); |
| 398 | } |
Thomas Gleixner | 0f44705 | 2015-07-14 12:01:04 +0200 | [diff] [blame] | 399 | EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control); |
Thomas Gleixner | f32dd11 | 2015-07-07 16:29:38 +0200 | [diff] [blame] | 400 | |
Thomas Gleixner | 52c063d | 2015-04-03 02:37:24 +0200 | [diff] [blame] | 401 | #ifdef CONFIG_HOTPLUG_CPU |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 402 | /* |
Sebastien Dugue | 94df7de | 2008-12-01 14:09:07 +0100 | [diff] [blame] | 403 | * Transfer the do_timer job away from a dying cpu. |
| 404 | * |
Thomas Gleixner | f12ad42 | 2020-12-06 22:12:54 +0100 | [diff] [blame] | 405 | * Called with interrupts disabled. No locking required. If |
Thomas Gleixner | 52c063d | 2015-04-03 02:37:24 +0200 | [diff] [blame] | 406 | * tick_do_timer_cpu is owned by this cpu, nothing can change it. |
Sebastien Dugue | 94df7de | 2008-12-01 14:09:07 +0100 | [diff] [blame] | 407 | */ |
Thomas Gleixner | 52c063d | 2015-04-03 02:37:24 +0200 | [diff] [blame] | 408 | void tick_handover_do_timer(void) |
Sebastien Dugue | 94df7de | 2008-12-01 14:09:07 +0100 | [diff] [blame] | 409 | { |
Thomas Gleixner | f12ad42 | 2020-12-06 22:12:54 +0100 | [diff] [blame] | 410 | if (tick_do_timer_cpu == smp_processor_id()) |
| 411 | tick_do_timer_cpu = cpumask_first(cpu_online_mask); |
Sebastien Dugue | 94df7de | 2008-12-01 14:09:07 +0100 | [diff] [blame] | 412 | } |
| 413 | |
| 414 | /* |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 415 | * Shutdown an event device on a given cpu: |
| 416 | * |
| 417 | * This is called on a life CPU, when a CPU is dead. So we cannot |
| 418 | * access the hardware device itself. |
| 419 | * We just set the mode and remove it from the lists. |
| 420 | */ |
Thomas Gleixner | a49b116 | 2015-04-03 02:38:05 +0200 | [diff] [blame] | 421 | void tick_shutdown(unsigned int cpu) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 422 | { |
Thomas Gleixner | a49b116 | 2015-04-03 02:38:05 +0200 | [diff] [blame] | 423 | struct tick_device *td = &per_cpu(tick_cpu_device, cpu); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 424 | struct clock_event_device *dev = td->evtdev; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 425 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 426 | td->mode = TICKDEV_MODE_PERIODIC; |
| 427 | if (dev) { |
| 428 | /* |
| 429 | * Prevent that the clock events layer tries to call |
| 430 | * the set mode function! |
| 431 | */ |
Thomas Gleixner | 051ebd1 | 2015-06-02 14:13:46 +0200 | [diff] [blame] | 432 | clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 433 | clockevents_exchange_device(dev, NULL); |
Thomas Gleixner | 6f7a05d7 | 2013-04-25 11:45:53 +0200 | [diff] [blame] | 434 | dev->event_handler = clockevents_handle_noop; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 435 | td->evtdev = NULL; |
| 436 | } |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 437 | } |
Thomas Gleixner | a49b116 | 2015-04-03 02:38:05 +0200 | [diff] [blame] | 438 | #endif |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 439 | |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 440 | /** |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 441 | * tick_suspend_local - Suspend the local tick device |
| 442 | * |
| 443 | * Called from the local cpu for freeze with interrupts disabled. |
| 444 | * |
| 445 | * No locks required. Nothing can change the per cpu device. |
| 446 | */ |
Thomas Gleixner | 7270d11 | 2015-03-25 13:11:52 +0100 | [diff] [blame] | 447 | void tick_suspend_local(void) |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 448 | { |
| 449 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
| 450 | |
| 451 | clockevents_shutdown(td->evtdev); |
| 452 | } |
| 453 | |
| 454 | /** |
| 455 | * tick_resume_local - Resume the local tick device |
| 456 | * |
| 457 | * Called from the local CPU for unfreeze or XEN resume magic. |
| 458 | * |
| 459 | * No locks required. Nothing can change the per cpu device. |
| 460 | */ |
| 461 | void tick_resume_local(void) |
| 462 | { |
| 463 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
| 464 | bool broadcast = tick_resume_check_broadcast(); |
| 465 | |
| 466 | clockevents_tick_resume(td->evtdev); |
| 467 | if (!broadcast) { |
| 468 | if (td->mode == TICKDEV_MODE_PERIODIC) |
| 469 | tick_setup_periodic(td->evtdev, 0); |
| 470 | else |
| 471 | tick_resume_oneshot(); |
| 472 | } |
Thomas Gleixner | a761a67 | 2021-07-13 15:39:51 +0200 | [diff] [blame] | 473 | |
| 474 | /* |
| 475 | * Ensure that hrtimers are up to date and the clockevents device |
| 476 | * is reprogrammed correctly when high resolution timers are |
| 477 | * enabled. |
| 478 | */ |
| 479 | hrtimers_resume_local(); |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 480 | } |
| 481 | |
| 482 | /** |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 483 | * tick_suspend - Suspend the tick and the broadcast device |
| 484 | * |
| 485 | * Called from syscore_suspend() via timekeeping_suspend with only one |
| 486 | * CPU online and interrupts disabled or from tick_unfreeze() under |
| 487 | * tick_freeze_lock. |
| 488 | * |
| 489 | * No locks required. Nothing can change the per cpu device. |
| 490 | */ |
Thomas Gleixner | 8c53daf | 2013-04-25 20:31:48 +0000 | [diff] [blame] | 491 | void tick_suspend(void) |
Thomas Gleixner | 6321dd6 | 2007-03-06 08:25:42 +0100 | [diff] [blame] | 492 | { |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 493 | tick_suspend_local(); |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 494 | tick_suspend_broadcast(); |
Thomas Gleixner | 6321dd6 | 2007-03-06 08:25:42 +0100 | [diff] [blame] | 495 | } |
| 496 | |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 497 | /** |
| 498 | * tick_resume - Resume the tick and the broadcast device |
| 499 | * |
| 500 | * Called from syscore_resume() via timekeeping_resume with only one |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 501 | * CPU online and interrupts disabled. |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 502 | * |
| 503 | * No locks required. Nothing can change the per cpu device. |
| 504 | */ |
Thomas Gleixner | 8c53daf | 2013-04-25 20:31:48 +0000 | [diff] [blame] | 505 | void tick_resume(void) |
Thomas Gleixner | 6321dd6 | 2007-03-06 08:25:42 +0100 | [diff] [blame] | 506 | { |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 507 | tick_resume_broadcast(); |
| 508 | tick_resume_local(); |
Thomas Gleixner | 6321dd6 | 2007-03-06 08:25:42 +0100 | [diff] [blame] | 509 | } |
| 510 | |
Rafael J. Wysocki | 87e9b9f | 2015-05-16 01:38:15 +0200 | [diff] [blame] | 511 | #ifdef CONFIG_SUSPEND |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 512 | static DEFINE_RAW_SPINLOCK(tick_freeze_lock); |
| 513 | static unsigned int tick_freeze_depth; |
| 514 | |
| 515 | /** |
| 516 | * tick_freeze - Suspend the local tick and (possibly) timekeeping. |
| 517 | * |
| 518 | * Check if this is the last online CPU executing the function and if so, |
| 519 | * suspend timekeeping. Otherwise suspend the local tick. |
| 520 | * |
| 521 | * Call with interrupts disabled. Must be balanced with %tick_unfreeze(). |
| 522 | * Interrupts must not be enabled before the subsequent %tick_unfreeze(). |
| 523 | */ |
| 524 | void tick_freeze(void) |
| 525 | { |
| 526 | raw_spin_lock(&tick_freeze_lock); |
| 527 | |
| 528 | tick_freeze_depth++; |
Rafael J. Wysocki | 75e0678 | 2015-05-10 01:23:35 +0200 | [diff] [blame] | 529 | if (tick_freeze_depth == num_online_cpus()) { |
| 530 | trace_suspend_resume(TPS("timekeeping_freeze"), |
| 531 | smp_processor_id(), true); |
Thomas Gleixner | c1a957d | 2018-05-25 17:54:41 +0200 | [diff] [blame] | 532 | system_state = SYSTEM_SUSPEND; |
Chang-An Chen | 3f2552f | 2019-03-29 10:59:09 +0800 | [diff] [blame] | 533 | sched_clock_suspend(); |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 534 | timekeeping_suspend(); |
Rafael J. Wysocki | 75e0678 | 2015-05-10 01:23:35 +0200 | [diff] [blame] | 535 | } else { |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 536 | tick_suspend_local(); |
Rafael J. Wysocki | 75e0678 | 2015-05-10 01:23:35 +0200 | [diff] [blame] | 537 | } |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 538 | |
| 539 | raw_spin_unlock(&tick_freeze_lock); |
| 540 | } |
| 541 | |
| 542 | /** |
| 543 | * tick_unfreeze - Resume the local tick and (possibly) timekeeping. |
| 544 | * |
| 545 | * Check if this is the first CPU executing the function and if so, resume |
| 546 | * timekeeping. Otherwise resume the local tick. |
| 547 | * |
| 548 | * Call with interrupts disabled. Must be balanced with %tick_freeze(). |
| 549 | * Interrupts must not be enabled after the preceding %tick_freeze(). |
| 550 | */ |
| 551 | void tick_unfreeze(void) |
| 552 | { |
| 553 | raw_spin_lock(&tick_freeze_lock); |
| 554 | |
Rafael J. Wysocki | 75e0678 | 2015-05-10 01:23:35 +0200 | [diff] [blame] | 555 | if (tick_freeze_depth == num_online_cpus()) { |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 556 | timekeeping_resume(); |
Chang-An Chen | 3f2552f | 2019-03-29 10:59:09 +0800 | [diff] [blame] | 557 | sched_clock_resume(); |
Thomas Gleixner | c1a957d | 2018-05-25 17:54:41 +0200 | [diff] [blame] | 558 | system_state = SYSTEM_RUNNING; |
Rafael J. Wysocki | 75e0678 | 2015-05-10 01:23:35 +0200 | [diff] [blame] | 559 | trace_suspend_resume(TPS("timekeeping_freeze"), |
| 560 | smp_processor_id(), false); |
| 561 | } else { |
Chunyan Zhang | 5167c50 | 2020-01-10 16:39:02 +0800 | [diff] [blame] | 562 | touch_softlockup_watchdog(); |
Rafael J. Wysocki | 422fe75 | 2015-04-03 15:21:51 +0200 | [diff] [blame] | 563 | tick_resume_local(); |
Rafael J. Wysocki | 75e0678 | 2015-05-10 01:23:35 +0200 | [diff] [blame] | 564 | } |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 565 | |
| 566 | tick_freeze_depth--; |
| 567 | |
| 568 | raw_spin_unlock(&tick_freeze_lock); |
| 569 | } |
Rafael J. Wysocki | 87e9b9f | 2015-05-16 01:38:15 +0200 | [diff] [blame] | 570 | #endif /* CONFIG_SUSPEND */ |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 571 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 572 | /** |
| 573 | * tick_init - initialize the tick control |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 574 | */ |
| 575 | void __init tick_init(void) |
| 576 | { |
Thomas Gleixner | b352bc1 | 2013-03-05 14:25:32 +0100 | [diff] [blame] | 577 | tick_broadcast_init(); |
Frederic Weisbecker | a80e49e | 2014-08-16 17:47:18 +0200 | [diff] [blame] | 578 | tick_nohz_init(); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 579 | } |