Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/time/tick-common.c |
| 3 | * |
| 4 | * This file contains the base functions to manage periodic tick |
| 5 | * related events. |
| 6 | * |
| 7 | * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> |
| 8 | * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar |
| 9 | * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner |
| 10 | * |
| 11 | * This code is licenced under the GPL version 2. For details see |
| 12 | * kernel-base/COPYING. |
| 13 | */ |
| 14 | #include <linux/cpu.h> |
| 15 | #include <linux/err.h> |
| 16 | #include <linux/hrtimer.h> |
Russell King | d7b9068 | 2008-04-17 07:46:24 +0200 | [diff] [blame] | 17 | #include <linux/interrupt.h> |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 18 | #include <linux/percpu.h> |
| 19 | #include <linux/profile.h> |
| 20 | #include <linux/sched.h> |
Thomas Gleixner | ccf33d6 | 2013-04-25 20:31:49 +0000 | [diff] [blame] | 21 | #include <linux/module.h> |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 22 | |
Russell King | d7b9068 | 2008-04-17 07:46:24 +0200 | [diff] [blame] | 23 | #include <asm/irq_regs.h> |
| 24 | |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 25 | #include "tick-internal.h" |
| 26 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 27 | /* |
| 28 | * Tick devices |
| 29 | */ |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 30 | DEFINE_PER_CPU(struct tick_device, tick_cpu_device); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 31 | /* |
| 32 | * Tick next event: keeps track of the tick time |
| 33 | */ |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 34 | ktime_t tick_next_period; |
| 35 | ktime_t tick_period; |
Andrew Morton | 050ded1 | 2013-11-15 14:15:33 -0800 | [diff] [blame] | 36 | |
| 37 | /* |
| 38 | * tick_do_timer_cpu is a timer core internal variable which holds the CPU NR |
| 39 | * which is responsible for calling do_timer(), i.e. the timekeeping stuff. This |
| 40 | * variable has two functions: |
| 41 | * |
| 42 | * 1) Prevent a thundering herd issue of a gazillion of CPUs trying to grab the |
| 43 | * timekeeping lock all at once. Only the CPU which is assigned to do the |
| 44 | * update is handling it. |
| 45 | * |
| 46 | * 2) Hand off the duty in the NOHZ idle case by setting the value to |
| 47 | * TICK_DO_TIMER_NONE, i.e. a non existing CPU. So the next cpu which looks |
| 48 | * at it will take over and keep the time keeping alive. The handover |
| 49 | * procedure also covers cpu hotplug. |
| 50 | */ |
Thomas Gleixner | 6441402 | 2008-09-22 18:46:37 +0200 | [diff] [blame] | 51 | int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 52 | |
Ingo Molnar | 289f480 | 2007-02-16 01:28:15 -0800 | [diff] [blame] | 53 | /* |
| 54 | * Debugging: see timer_list.c |
| 55 | */ |
| 56 | struct tick_device *tick_get_device(int cpu) |
| 57 | { |
| 58 | return &per_cpu(tick_cpu_device, cpu); |
| 59 | } |
| 60 | |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 61 | /** |
| 62 | * tick_is_oneshot_available - check for a oneshot capable event device |
| 63 | */ |
| 64 | int tick_is_oneshot_available(void) |
| 65 | { |
Christoph Lameter | 909ea96 | 2010-12-08 16:22:55 +0100 | [diff] [blame] | 66 | struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 67 | |
Thomas Gleixner | 3a142a0 | 2011-02-25 22:34:23 +0100 | [diff] [blame] | 68 | if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT)) |
| 69 | return 0; |
| 70 | if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) |
| 71 | return 1; |
| 72 | return tick_broadcast_oneshot_available(); |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 73 | } |
| 74 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 75 | /* |
| 76 | * Periodic tick |
| 77 | */ |
| 78 | static void tick_periodic(int cpu) |
| 79 | { |
| 80 | if (tick_do_timer_cpu == cpu) { |
John Stultz | d6ad418 | 2012-02-28 16:50:11 -0800 | [diff] [blame] | 81 | write_seqlock(&jiffies_lock); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 82 | |
| 83 | /* Keep track of the next tick event */ |
| 84 | tick_next_period = ktime_add(tick_next_period, tick_period); |
| 85 | |
| 86 | do_timer(1); |
John Stultz | d6ad418 | 2012-02-28 16:50:11 -0800 | [diff] [blame] | 87 | write_sequnlock(&jiffies_lock); |
John Stultz | 47a1b796 | 2013-12-12 13:10:55 -0800 | [diff] [blame] | 88 | update_wall_time(); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | update_process_times(user_mode(get_irq_regs())); |
| 92 | profile_tick(CPU_PROFILING); |
| 93 | } |
| 94 | |
| 95 | /* |
| 96 | * Event handler for periodic ticks |
| 97 | */ |
| 98 | void tick_handle_periodic(struct clock_event_device *dev) |
| 99 | { |
| 100 | int cpu = smp_processor_id(); |
Viresh Kumar | b97f029 | 2014-03-25 13:56:23 +0530 | [diff] [blame] | 101 | ktime_t next = dev->next_event; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 102 | |
| 103 | tick_periodic(cpu); |
| 104 | |
Thomas Gleixner | c6eb3f7 | 2015-04-14 21:08:51 +0000 | [diff] [blame^] | 105 | #if defined(CONFIG_HIGH_RES_TIMERS) || defined(CONFIG_NO_HZ_COMMON) |
| 106 | /* |
| 107 | * The cpu might have transitioned to HIGHRES or NOHZ mode via |
| 108 | * update_process_times() -> run_local_timers() -> |
| 109 | * hrtimer_run_queues(). |
| 110 | */ |
| 111 | if (dev->event_handler != tick_handle_periodic) |
| 112 | return; |
| 113 | #endif |
| 114 | |
Viresh Kumar | 77e32c8 | 2015-02-27 17:21:33 +0530 | [diff] [blame] | 115 | if (dev->state != CLOCK_EVT_STATE_ONESHOT) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 116 | return; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 117 | for (;;) { |
Viresh Kumar | b97f029 | 2014-03-25 13:56:23 +0530 | [diff] [blame] | 118 | /* |
| 119 | * Setup the next period for devices, which do not have |
| 120 | * periodic mode: |
| 121 | */ |
| 122 | next = ktime_add(next, tick_period); |
| 123 | |
Martin Schwidefsky | d174830 | 2011-08-23 15:29:42 +0200 | [diff] [blame] | 124 | if (!clockevents_program_event(dev, next, false)) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 125 | return; |
john stultz | 74a03b6 | 2009-05-01 13:10:25 -0700 | [diff] [blame] | 126 | /* |
| 127 | * Have to be careful here. If we're in oneshot mode, |
| 128 | * before we call tick_periodic() in a loop, we need |
| 129 | * to be sure we're using a real hardware clocksource. |
| 130 | * Otherwise we could get trapped in an infinite |
| 131 | * loop, as the tick_periodic() increments jiffies, |
Viresh Kumar | cacb3c7 | 2014-03-25 16:09:18 +0530 | [diff] [blame] | 132 | * which then will increment time, possibly causing |
john stultz | 74a03b6 | 2009-05-01 13:10:25 -0700 | [diff] [blame] | 133 | * the loop to trigger again and again. |
| 134 | */ |
| 135 | if (timekeeping_valid_for_hres()) |
| 136 | tick_periodic(cpu); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 137 | } |
| 138 | } |
| 139 | |
| 140 | /* |
| 141 | * Setup the device for a periodic tick |
| 142 | */ |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 143 | void tick_setup_periodic(struct clock_event_device *dev, int broadcast) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 144 | { |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 145 | tick_set_periodic_handler(dev, broadcast); |
| 146 | |
| 147 | /* Broadcast setup ? */ |
| 148 | if (!tick_device_is_functional(dev)) |
| 149 | return; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 150 | |
Thomas Gleixner | 27ce4cb | 2008-09-22 19:04:02 +0200 | [diff] [blame] | 151 | if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) && |
| 152 | !tick_broadcast_oneshot_active()) { |
Viresh Kumar | 77e32c8 | 2015-02-27 17:21:33 +0530 | [diff] [blame] | 153 | clockevents_set_state(dev, CLOCK_EVT_STATE_PERIODIC); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 154 | } else { |
| 155 | unsigned long seq; |
| 156 | ktime_t next; |
| 157 | |
| 158 | do { |
John Stultz | d6ad418 | 2012-02-28 16:50:11 -0800 | [diff] [blame] | 159 | seq = read_seqbegin(&jiffies_lock); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 160 | next = tick_next_period; |
John Stultz | d6ad418 | 2012-02-28 16:50:11 -0800 | [diff] [blame] | 161 | } while (read_seqretry(&jiffies_lock, seq)); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 162 | |
Viresh Kumar | 77e32c8 | 2015-02-27 17:21:33 +0530 | [diff] [blame] | 163 | clockevents_set_state(dev, CLOCK_EVT_STATE_ONESHOT); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 164 | |
| 165 | for (;;) { |
Martin Schwidefsky | d174830 | 2011-08-23 15:29:42 +0200 | [diff] [blame] | 166 | if (!clockevents_program_event(dev, next, false)) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 167 | return; |
| 168 | next = ktime_add(next, tick_period); |
| 169 | } |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * Setup the tick device |
| 175 | */ |
| 176 | static void tick_setup_device(struct tick_device *td, |
| 177 | struct clock_event_device *newdev, int cpu, |
Rusty Russell | 0de2652 | 2008-12-13 21:20:26 +1030 | [diff] [blame] | 178 | const struct cpumask *cpumask) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 179 | { |
| 180 | ktime_t next_event; |
| 181 | void (*handler)(struct clock_event_device *) = NULL; |
| 182 | |
| 183 | /* |
| 184 | * First device setup ? |
| 185 | */ |
| 186 | if (!td->evtdev) { |
| 187 | /* |
| 188 | * If no cpu took the do_timer update, assign it to |
| 189 | * this cpu: |
| 190 | */ |
Thomas Gleixner | 6441402 | 2008-09-22 18:46:37 +0200 | [diff] [blame] | 191 | if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) { |
Frederic Weisbecker | c5bfece | 2013-04-12 16:45:34 +0200 | [diff] [blame] | 192 | if (!tick_nohz_full_cpu(cpu)) |
Frederic Weisbecker | a382bf9 | 2012-12-18 18:24:35 +0100 | [diff] [blame] | 193 | tick_do_timer_cpu = cpu; |
| 194 | else |
| 195 | tick_do_timer_cpu = TICK_DO_TIMER_NONE; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 196 | tick_next_period = ktime_get(); |
| 197 | tick_period = ktime_set(0, NSEC_PER_SEC / HZ); |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * Startup in periodic mode first. |
| 202 | */ |
| 203 | td->mode = TICKDEV_MODE_PERIODIC; |
| 204 | } else { |
| 205 | handler = td->evtdev->event_handler; |
| 206 | next_event = td->evtdev->next_event; |
Venkatesh Pallipadi | 7c1e768 | 2008-09-03 21:36:50 +0000 | [diff] [blame] | 207 | td->evtdev->event_handler = clockevents_handle_noop; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 208 | } |
| 209 | |
| 210 | td->evtdev = newdev; |
| 211 | |
| 212 | /* |
| 213 | * When the device is not per cpu, pin the interrupt to the |
| 214 | * current cpu: |
| 215 | */ |
Rusty Russell | 320ab2b | 2008-12-13 21:20:26 +1030 | [diff] [blame] | 216 | if (!cpumask_equal(newdev->cpumask, cpumask)) |
Rusty Russell | 0de2652 | 2008-12-13 21:20:26 +1030 | [diff] [blame] | 217 | irq_set_affinity(newdev->irq, cpumask); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 218 | |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 219 | /* |
| 220 | * When global broadcasting is active, check if the current |
| 221 | * device is registered as a placeholder for broadcast mode. |
| 222 | * This allows us to handle this x86 misfeature in a generic |
Thomas Gleixner | 07bd117 | 2013-07-01 22:14:10 +0200 | [diff] [blame] | 223 | * way. This function also returns !=0 when we keep the |
| 224 | * current active broadcast state for this CPU. |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 225 | */ |
| 226 | if (tick_device_uses_broadcast(newdev, cpu)) |
| 227 | return; |
| 228 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 229 | if (td->mode == TICKDEV_MODE_PERIODIC) |
| 230 | tick_setup_periodic(newdev, 0); |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 231 | else |
| 232 | tick_setup_oneshot(newdev, handler, next_event); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 233 | } |
| 234 | |
Thomas Gleixner | 03e13cf | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 235 | void tick_install_replacement(struct clock_event_device *newdev) |
| 236 | { |
Christoph Lameter | 22127e9 | 2014-08-17 12:30:25 -0500 | [diff] [blame] | 237 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
Thomas Gleixner | 03e13cf | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 238 | int cpu = smp_processor_id(); |
| 239 | |
| 240 | clockevents_exchange_device(td->evtdev, newdev); |
| 241 | tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); |
| 242 | if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) |
| 243 | tick_oneshot_notify(); |
| 244 | } |
| 245 | |
Thomas Gleixner | 45cb8e0 | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 246 | static bool tick_check_percpu(struct clock_event_device *curdev, |
| 247 | struct clock_event_device *newdev, int cpu) |
| 248 | { |
| 249 | if (!cpumask_test_cpu(cpu, newdev->cpumask)) |
| 250 | return false; |
| 251 | if (cpumask_equal(newdev->cpumask, cpumask_of(cpu))) |
| 252 | return true; |
| 253 | /* Check if irq affinity can be set */ |
| 254 | if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq)) |
| 255 | return false; |
| 256 | /* Prefer an existing cpu local device */ |
| 257 | if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu))) |
| 258 | return false; |
| 259 | return true; |
| 260 | } |
| 261 | |
| 262 | static bool tick_check_preferred(struct clock_event_device *curdev, |
| 263 | struct clock_event_device *newdev) |
| 264 | { |
| 265 | /* Prefer oneshot capable device */ |
| 266 | if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) { |
| 267 | if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT)) |
| 268 | return false; |
| 269 | if (tick_oneshot_mode_active()) |
| 270 | return false; |
| 271 | } |
| 272 | |
Stephen Boyd | 70e5975 | 2013-06-13 11:39:50 -0700 | [diff] [blame] | 273 | /* |
| 274 | * Use the higher rated one, but prefer a CPU local device with a lower |
| 275 | * rating than a non-CPU local device |
| 276 | */ |
| 277 | return !curdev || |
| 278 | newdev->rating > curdev->rating || |
| 279 | !cpumask_equal(curdev->cpumask, newdev->cpumask); |
Thomas Gleixner | 45cb8e0 | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 280 | } |
| 281 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 282 | /* |
Thomas Gleixner | 03e13cf | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 283 | * Check whether the new device is a better fit than curdev. curdev |
| 284 | * can be NULL ! |
| 285 | */ |
| 286 | bool tick_check_replacement(struct clock_event_device *curdev, |
| 287 | struct clock_event_device *newdev) |
| 288 | { |
Viresh Kumar | 521c429 | 2014-04-15 10:54:37 +0530 | [diff] [blame] | 289 | if (!tick_check_percpu(curdev, newdev, smp_processor_id())) |
Thomas Gleixner | 03e13cf | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 290 | return false; |
| 291 | |
| 292 | return tick_check_preferred(curdev, newdev); |
| 293 | } |
| 294 | |
| 295 | /* |
Thomas Gleixner | 7126cac | 2013-04-25 20:31:48 +0000 | [diff] [blame] | 296 | * Check, if the new registered device should be used. Called with |
| 297 | * clockevents_lock held and interrupts disabled. |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 298 | */ |
Thomas Gleixner | 7172a28 | 2013-04-25 20:31:47 +0000 | [diff] [blame] | 299 | void tick_check_new_device(struct clock_event_device *newdev) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 300 | { |
| 301 | struct clock_event_device *curdev; |
| 302 | struct tick_device *td; |
Thomas Gleixner | 7172a28 | 2013-04-25 20:31:47 +0000 | [diff] [blame] | 303 | int cpu; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 304 | |
| 305 | cpu = smp_processor_id(); |
Rusty Russell | 320ab2b | 2008-12-13 21:20:26 +1030 | [diff] [blame] | 306 | if (!cpumask_test_cpu(cpu, newdev->cpumask)) |
Venki Pallipadi | 4a93232 | 2007-10-12 23:04:23 +0200 | [diff] [blame] | 307 | goto out_bc; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 308 | |
| 309 | td = &per_cpu(tick_cpu_device, cpu); |
| 310 | curdev = td->evtdev; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 311 | |
| 312 | /* cpu local device ? */ |
Thomas Gleixner | 45cb8e0 | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 313 | if (!tick_check_percpu(curdev, newdev, cpu)) |
| 314 | goto out_bc; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 315 | |
Thomas Gleixner | 45cb8e0 | 2013-04-25 20:31:50 +0000 | [diff] [blame] | 316 | /* Preference decision */ |
| 317 | if (!tick_check_preferred(curdev, newdev)) |
| 318 | goto out_bc; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 319 | |
Thomas Gleixner | ccf33d6 | 2013-04-25 20:31:49 +0000 | [diff] [blame] | 320 | if (!try_module_get(newdev->owner)) |
| 321 | return; |
| 322 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 323 | /* |
| 324 | * Replace the eventually existing device by the new |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 325 | * device. If the current device is the broadcast device, do |
| 326 | * not give it back to the clockevents layer ! |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 327 | */ |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 328 | if (tick_is_broadcast_device(curdev)) { |
Thomas Gleixner | 2344abb | 2008-09-16 11:32:50 -0700 | [diff] [blame] | 329 | clockevents_shutdown(curdev); |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 330 | curdev = NULL; |
| 331 | } |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 332 | clockevents_exchange_device(curdev, newdev); |
Rusty Russell | 6b95482 | 2009-01-01 10:12:25 +1030 | [diff] [blame] | 333 | tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); |
Thomas Gleixner | 79bf2bb | 2007-02-16 01:28:03 -0800 | [diff] [blame] | 334 | if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) |
| 335 | tick_oneshot_notify(); |
Thomas Gleixner | 7172a28 | 2013-04-25 20:31:47 +0000 | [diff] [blame] | 336 | return; |
Thomas Gleixner | f8381cb | 2007-02-16 01:28:02 -0800 | [diff] [blame] | 337 | |
| 338 | out_bc: |
| 339 | /* |
| 340 | * Can the new device be used as a broadcast device ? |
| 341 | */ |
Thomas Gleixner | 7172a28 | 2013-04-25 20:31:47 +0000 | [diff] [blame] | 342 | tick_install_broadcast_device(newdev); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 343 | } |
| 344 | |
Thomas Gleixner | 52c063d | 2015-04-03 02:37:24 +0200 | [diff] [blame] | 345 | #ifdef CONFIG_HOTPLUG_CPU |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 346 | /* |
Sebastien Dugue | 94df7de | 2008-12-01 14:09:07 +0100 | [diff] [blame] | 347 | * Transfer the do_timer job away from a dying cpu. |
| 348 | * |
Thomas Gleixner | 52c063d | 2015-04-03 02:37:24 +0200 | [diff] [blame] | 349 | * Called with interrupts disabled. Not locking required. If |
| 350 | * 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] | 351 | */ |
Thomas Gleixner | 52c063d | 2015-04-03 02:37:24 +0200 | [diff] [blame] | 352 | void tick_handover_do_timer(void) |
Sebastien Dugue | 94df7de | 2008-12-01 14:09:07 +0100 | [diff] [blame] | 353 | { |
Thomas Gleixner | 52c063d | 2015-04-03 02:37:24 +0200 | [diff] [blame] | 354 | if (tick_do_timer_cpu == smp_processor_id()) { |
Sebastien Dugue | 94df7de | 2008-12-01 14:09:07 +0100 | [diff] [blame] | 355 | int cpu = cpumask_first(cpu_online_mask); |
| 356 | |
| 357 | tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu : |
| 358 | TICK_DO_TIMER_NONE; |
| 359 | } |
| 360 | } |
| 361 | |
| 362 | /* |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 363 | * Shutdown an event device on a given cpu: |
| 364 | * |
| 365 | * This is called on a life CPU, when a CPU is dead. So we cannot |
| 366 | * access the hardware device itself. |
| 367 | * We just set the mode and remove it from the lists. |
| 368 | */ |
Thomas Gleixner | a49b116 | 2015-04-03 02:38:05 +0200 | [diff] [blame] | 369 | void tick_shutdown(unsigned int cpu) |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 370 | { |
Thomas Gleixner | a49b116 | 2015-04-03 02:38:05 +0200 | [diff] [blame] | 371 | struct tick_device *td = &per_cpu(tick_cpu_device, cpu); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 372 | struct clock_event_device *dev = td->evtdev; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 373 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 374 | td->mode = TICKDEV_MODE_PERIODIC; |
| 375 | if (dev) { |
| 376 | /* |
| 377 | * Prevent that the clock events layer tries to call |
| 378 | * the set mode function! |
| 379 | */ |
Viresh Kumar | 77e32c8 | 2015-02-27 17:21:33 +0530 | [diff] [blame] | 380 | dev->state = CLOCK_EVT_STATE_DETACHED; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 381 | dev->mode = CLOCK_EVT_MODE_UNUSED; |
| 382 | clockevents_exchange_device(dev, NULL); |
Thomas Gleixner | 6f7a05d | 2013-04-25 11:45:53 +0200 | [diff] [blame] | 383 | dev->event_handler = clockevents_handle_noop; |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 384 | td->evtdev = NULL; |
| 385 | } |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 386 | } |
Thomas Gleixner | a49b116 | 2015-04-03 02:38:05 +0200 | [diff] [blame] | 387 | #endif |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 388 | |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 389 | /** |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 390 | * tick_suspend_local - Suspend the local tick device |
| 391 | * |
| 392 | * Called from the local cpu for freeze with interrupts disabled. |
| 393 | * |
| 394 | * No locks required. Nothing can change the per cpu device. |
| 395 | */ |
Thomas Gleixner | 7270d11 | 2015-03-25 13:11:52 +0100 | [diff] [blame] | 396 | void tick_suspend_local(void) |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 397 | { |
| 398 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
| 399 | |
| 400 | clockevents_shutdown(td->evtdev); |
| 401 | } |
| 402 | |
| 403 | /** |
| 404 | * tick_resume_local - Resume the local tick device |
| 405 | * |
| 406 | * Called from the local CPU for unfreeze or XEN resume magic. |
| 407 | * |
| 408 | * No locks required. Nothing can change the per cpu device. |
| 409 | */ |
| 410 | void tick_resume_local(void) |
| 411 | { |
| 412 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
| 413 | bool broadcast = tick_resume_check_broadcast(); |
| 414 | |
| 415 | clockevents_tick_resume(td->evtdev); |
| 416 | if (!broadcast) { |
| 417 | if (td->mode == TICKDEV_MODE_PERIODIC) |
| 418 | tick_setup_periodic(td->evtdev, 0); |
| 419 | else |
| 420 | tick_resume_oneshot(); |
| 421 | } |
| 422 | } |
| 423 | |
| 424 | /** |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 425 | * tick_suspend - Suspend the tick and the broadcast device |
| 426 | * |
| 427 | * Called from syscore_suspend() via timekeeping_suspend with only one |
| 428 | * CPU online and interrupts disabled or from tick_unfreeze() under |
| 429 | * tick_freeze_lock. |
| 430 | * |
| 431 | * No locks required. Nothing can change the per cpu device. |
| 432 | */ |
Thomas Gleixner | 8c53daf | 2013-04-25 20:31:48 +0000 | [diff] [blame] | 433 | void tick_suspend(void) |
Thomas Gleixner | 6321dd6 | 2007-03-06 08:25:42 +0100 | [diff] [blame] | 434 | { |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 435 | tick_suspend_local(); |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 436 | tick_suspend_broadcast(); |
Thomas Gleixner | 6321dd6 | 2007-03-06 08:25:42 +0100 | [diff] [blame] | 437 | } |
| 438 | |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 439 | /** |
| 440 | * tick_resume - Resume the tick and the broadcast device |
| 441 | * |
| 442 | * Called from syscore_resume() via timekeeping_resume with only one |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 443 | * CPU online and interrupts disabled. |
Thomas Gleixner | 4ffee52 | 2015-03-25 13:09:16 +0100 | [diff] [blame] | 444 | * |
| 445 | * No locks required. Nothing can change the per cpu device. |
| 446 | */ |
Thomas Gleixner | 8c53daf | 2013-04-25 20:31:48 +0000 | [diff] [blame] | 447 | void tick_resume(void) |
Thomas Gleixner | 6321dd6 | 2007-03-06 08:25:42 +0100 | [diff] [blame] | 448 | { |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 449 | tick_resume_broadcast(); |
| 450 | tick_resume_local(); |
Thomas Gleixner | 6321dd6 | 2007-03-06 08:25:42 +0100 | [diff] [blame] | 451 | } |
| 452 | |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 453 | static DEFINE_RAW_SPINLOCK(tick_freeze_lock); |
| 454 | static unsigned int tick_freeze_depth; |
| 455 | |
| 456 | /** |
| 457 | * tick_freeze - Suspend the local tick and (possibly) timekeeping. |
| 458 | * |
| 459 | * Check if this is the last online CPU executing the function and if so, |
| 460 | * suspend timekeeping. Otherwise suspend the local tick. |
| 461 | * |
| 462 | * Call with interrupts disabled. Must be balanced with %tick_unfreeze(). |
| 463 | * Interrupts must not be enabled before the subsequent %tick_unfreeze(). |
| 464 | */ |
| 465 | void tick_freeze(void) |
| 466 | { |
| 467 | raw_spin_lock(&tick_freeze_lock); |
| 468 | |
| 469 | tick_freeze_depth++; |
Rafael J. Wysocki | def7470 | 2015-04-03 15:31:32 +0200 | [diff] [blame] | 470 | if (tick_freeze_depth == num_online_cpus()) |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 471 | timekeeping_suspend(); |
Rafael J. Wysocki | def7470 | 2015-04-03 15:31:32 +0200 | [diff] [blame] | 472 | else |
Thomas Gleixner | f46481d | 2015-03-25 13:11:04 +0100 | [diff] [blame] | 473 | tick_suspend_local(); |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 474 | |
| 475 | raw_spin_unlock(&tick_freeze_lock); |
| 476 | } |
| 477 | |
| 478 | /** |
| 479 | * tick_unfreeze - Resume the local tick and (possibly) timekeeping. |
| 480 | * |
| 481 | * Check if this is the first CPU executing the function and if so, resume |
| 482 | * timekeeping. Otherwise resume the local tick. |
| 483 | * |
| 484 | * Call with interrupts disabled. Must be balanced with %tick_freeze(). |
| 485 | * Interrupts must not be enabled after the preceding %tick_freeze(). |
| 486 | */ |
| 487 | void tick_unfreeze(void) |
| 488 | { |
| 489 | raw_spin_lock(&tick_freeze_lock); |
| 490 | |
| 491 | if (tick_freeze_depth == num_online_cpus()) |
| 492 | timekeeping_resume(); |
| 493 | else |
Rafael J. Wysocki | 422fe75 | 2015-04-03 15:21:51 +0200 | [diff] [blame] | 494 | tick_resume_local(); |
Rafael J. Wysocki | 124cf911 | 2015-02-13 23:50:43 +0100 | [diff] [blame] | 495 | |
| 496 | tick_freeze_depth--; |
| 497 | |
| 498 | raw_spin_unlock(&tick_freeze_lock); |
| 499 | } |
| 500 | |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 501 | /** |
| 502 | * tick_init - initialize the tick control |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 503 | */ |
| 504 | void __init tick_init(void) |
| 505 | { |
Thomas Gleixner | b352bc1 | 2013-03-05 14:25:32 +0100 | [diff] [blame] | 506 | tick_broadcast_init(); |
Frederic Weisbecker | a80e49e | 2014-08-16 17:47:18 +0200 | [diff] [blame] | 507 | tick_nohz_init(); |
Thomas Gleixner | 906568c | 2007-02-16 01:28:01 -0800 | [diff] [blame] | 508 | } |