Doug / smarc-fsl-linux-kernel

Download as
Browse Code ยป

Commit a7dc19b8652c862d5b7c4d2339bd3c428bd29c4a

Authored by Mark Rutland
Committed by Thomas Gleixner
1 parent 6dbe51c251
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

clockevents: Don't allow dummy broadcast timers 

Currently tick_check_broadcast_device doesn't reject clock_event_devices
with CLOCK_EVT_FEAT_DUMMY, and may select them in preference to real
hardware if they have a higher rating value. In this situation, the
dummy timer is responsible for broadcasting to itself, and the core
clockevents code may attempt to call non-existent callbacks for
programming the dummy, eventually leading to a panic.

This patch makes tick_check_broadcast_device always reject dummy timers,
preventing this problem.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Jon Medhurst (Tixy) <tixy@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Showing 1 changed file with 2 additions and 1 deletions Inline Diff

kernel/time/tick-broadcast.c
Diff comments   View file @ a7dc19b
1 /* 1 /*
2 * linux/kernel/time/tick-broadcast.c 2 * linux/kernel/time/tick-broadcast.c
3 * 3 *
4 * This file contains functions which emulate a local clock-event 4 * This file contains functions which emulate a local clock-event
5 * device via a broadcast event source. 5 * device via a broadcast event source.
6 * 6 *
7 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> 7 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
8 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar 8 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
9 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner 9 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
10 * 10 *
11 * This code is licenced under the GPL version 2. For details see 11 * This code is licenced under the GPL version 2. For details see
12 * kernel-base/COPYING. 12 * kernel-base/COPYING.
13 */ 13 */
14 #include <linux/cpu.h> 14 #include <linux/cpu.h>
15 #include <linux/err.h> 15 #include <linux/err.h>
16 #include <linux/hrtimer.h> 16 #include <linux/hrtimer.h>
17 #include <linux/interrupt.h> 17 #include <linux/interrupt.h>
18 #include <linux/percpu.h> 18 #include <linux/percpu.h>
19 #include <linux/profile.h> 19 #include <linux/profile.h>
20 #include <linux/sched.h> 20 #include <linux/sched.h>
21 #include <linux/smp.h> 21 #include <linux/smp.h>
22 22
23 #include "tick-internal.h" 23 #include "tick-internal.h"
24 24
25 /* 25 /*
26 * Broadcast support for broken x86 hardware, where the local apic 26 * Broadcast support for broken x86 hardware, where the local apic
27 * timer stops in C3 state. 27 * timer stops in C3 state.
28 */ 28 */
29 29
30 static struct tick_device tick_broadcast_device; 30 static struct tick_device tick_broadcast_device;
31 /* FIXME: Use cpumask_var_t. */ 31 /* FIXME: Use cpumask_var_t. */
32 static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS); 32 static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS);
33 static DECLARE_BITMAP(tmpmask, NR_CPUS); 33 static DECLARE_BITMAP(tmpmask, NR_CPUS);
34 static DEFINE_RAW_SPINLOCK(tick_broadcast_lock); 34 static DEFINE_RAW_SPINLOCK(tick_broadcast_lock);
35 static int tick_broadcast_force; 35 static int tick_broadcast_force;
36 36
37 #ifdef CONFIG_TICK_ONESHOT 37 #ifdef CONFIG_TICK_ONESHOT
38 static void tick_broadcast_clear_oneshot(int cpu); 38 static void tick_broadcast_clear_oneshot(int cpu);
39 #else 39 #else
40 static inline void tick_broadcast_clear_oneshot(int cpu) { } 40 static inline void tick_broadcast_clear_oneshot(int cpu) { }
41 #endif 41 #endif
42 42
43 /* 43 /*
44 * Debugging: see timer_list.c 44 * Debugging: see timer_list.c
45 */ 45 */
46 struct tick_device *tick_get_broadcast_device(void) 46 struct tick_device *tick_get_broadcast_device(void)
47 { 47 {
48 return &tick_broadcast_device; 48 return &tick_broadcast_device;
49 } 49 }
50 50
51 struct cpumask *tick_get_broadcast_mask(void) 51 struct cpumask *tick_get_broadcast_mask(void)
52 { 52 {
53 return to_cpumask(tick_broadcast_mask); 53 return to_cpumask(tick_broadcast_mask);
54 } 54 }
55 55
56 /* 56 /*
57 * Start the device in periodic mode 57 * Start the device in periodic mode
58 */ 58 */
59 static void tick_broadcast_start_periodic(struct clock_event_device *bc) 59 static void tick_broadcast_start_periodic(struct clock_event_device *bc)
60 { 60 {
61 if (bc) 61 if (bc)
62 tick_setup_periodic(bc, 1); 62 tick_setup_periodic(bc, 1);
63 } 63 }
64 64
65 /* 65 /*
66 * Check, if the device can be utilized as broadcast device: 66 * Check, if the device can be utilized as broadcast device:
67 */ 67 */
68 int tick_check_broadcast_device(struct clock_event_device *dev) 68 int tick_check_broadcast_device(struct clock_event_device *dev)
69 { 69 {
70 if ((tick_broadcast_device.evtdev && 70 if ((dev->features & CLOCK_EVT_FEAT_DUMMY) ||
71 (tick_broadcast_device.evtdev &&
71 tick_broadcast_device.evtdev->rating >= dev->rating) || 72 tick_broadcast_device.evtdev->rating >= dev->rating) ||
72 (dev->features & CLOCK_EVT_FEAT_C3STOP)) 73 (dev->features & CLOCK_EVT_FEAT_C3STOP))
73 return 0; 74 return 0;
74 75
75 clockevents_exchange_device(tick_broadcast_device.evtdev, dev); 76 clockevents_exchange_device(tick_broadcast_device.evtdev, dev);
76 tick_broadcast_device.evtdev = dev; 77 tick_broadcast_device.evtdev = dev;
77 if (!cpumask_empty(tick_get_broadcast_mask())) 78 if (!cpumask_empty(tick_get_broadcast_mask()))
78 tick_broadcast_start_periodic(dev); 79 tick_broadcast_start_periodic(dev);
79 return 1; 80 return 1;
80 } 81 }
81 82
82 /* 83 /*
83 * Check, if the device is the broadcast device 84 * Check, if the device is the broadcast device
84 */ 85 */
85 int tick_is_broadcast_device(struct clock_event_device *dev) 86 int tick_is_broadcast_device(struct clock_event_device *dev)
86 { 87 {
87 return (dev && tick_broadcast_device.evtdev == dev); 88 return (dev && tick_broadcast_device.evtdev == dev);
88 } 89 }
89 90
90 static void err_broadcast(const struct cpumask *mask) 91 static void err_broadcast(const struct cpumask *mask)
91 { 92 {
92 pr_crit_once("Failed to broadcast timer tick. Some CPUs may be unresponsive.\n"); 93 pr_crit_once("Failed to broadcast timer tick. Some CPUs may be unresponsive.\n");
93 } 94 }
94 95
95 static void tick_device_setup_broadcast_func(struct clock_event_device *dev) 96 static void tick_device_setup_broadcast_func(struct clock_event_device *dev)
96 { 97 {
97 if (!dev->broadcast) 98 if (!dev->broadcast)
98 dev->broadcast = tick_broadcast; 99 dev->broadcast = tick_broadcast;
99 if (!dev->broadcast) { 100 if (!dev->broadcast) {
100 pr_warn_once("%s depends on broadcast, but no broadcast function available\n", 101 pr_warn_once("%s depends on broadcast, but no broadcast function available\n",
101 dev->name); 102 dev->name);
102 dev->broadcast = err_broadcast; 103 dev->broadcast = err_broadcast;
103 } 104 }
104 } 105 }
105 106
106 /* 107 /*
107 * Check, if the device is disfunctional and a place holder, which 108 * Check, if the device is disfunctional and a place holder, which
108 * needs to be handled by the broadcast device. 109 * needs to be handled by the broadcast device.
109 */ 110 */
110 int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) 111 int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
111 { 112 {
112 unsigned long flags; 113 unsigned long flags;
113 int ret = 0; 114 int ret = 0;
114 115
115 raw_spin_lock_irqsave(&tick_broadcast_lock, flags); 116 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
116 117
117 /* 118 /*
118 * Devices might be registered with both periodic and oneshot 119 * Devices might be registered with both periodic and oneshot
119 * mode disabled. This signals, that the device needs to be 120 * mode disabled. This signals, that the device needs to be
120 * operated from the broadcast device and is a placeholder for 121 * operated from the broadcast device and is a placeholder for
121 * the cpu local device. 122 * the cpu local device.
122 */ 123 */
123 if (!tick_device_is_functional(dev)) { 124 if (!tick_device_is_functional(dev)) {
124 dev->event_handler = tick_handle_periodic; 125 dev->event_handler = tick_handle_periodic;
125 tick_device_setup_broadcast_func(dev); 126 tick_device_setup_broadcast_func(dev);
126 cpumask_set_cpu(cpu, tick_get_broadcast_mask()); 127 cpumask_set_cpu(cpu, tick_get_broadcast_mask());
127 tick_broadcast_start_periodic(tick_broadcast_device.evtdev); 128 tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
128 ret = 1; 129 ret = 1;
129 } else { 130 } else {
130 /* 131 /*
131 * When the new device is not affected by the stop 132 * When the new device is not affected by the stop
132 * feature and the cpu is marked in the broadcast mask 133 * feature and the cpu is marked in the broadcast mask
133 * then clear the broadcast bit. 134 * then clear the broadcast bit.
134 */ 135 */
135 if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) { 136 if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
136 int cpu = smp_processor_id(); 137 int cpu = smp_processor_id();
137 cpumask_clear_cpu(cpu, tick_get_broadcast_mask()); 138 cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
138 tick_broadcast_clear_oneshot(cpu); 139 tick_broadcast_clear_oneshot(cpu);
139 } else { 140 } else {
140 tick_device_setup_broadcast_func(dev); 141 tick_device_setup_broadcast_func(dev);
141 } 142 }
142 } 143 }
143 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); 144 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
144 return ret; 145 return ret;
145 } 146 }
146 147
147 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 148 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
148 int tick_receive_broadcast(void) 149 int tick_receive_broadcast(void)
149 { 150 {
150 struct tick_device *td = this_cpu_ptr(&tick_cpu_device); 151 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
151 struct clock_event_device *evt = td->evtdev; 152 struct clock_event_device *evt = td->evtdev;
152 153
153 if (!evt) 154 if (!evt)
154 return -ENODEV; 155 return -ENODEV;
155 156
156 if (!evt->event_handler) 157 if (!evt->event_handler)
157 return -EINVAL; 158 return -EINVAL;
158 159
159 evt->event_handler(evt); 160 evt->event_handler(evt);
160 return 0; 161 return 0;
161 } 162 }
162 #endif 163 #endif
163 164
164 /* 165 /*
165 * Broadcast the event to the cpus, which are set in the mask (mangled). 166 * Broadcast the event to the cpus, which are set in the mask (mangled).
166 */ 167 */
167 static void tick_do_broadcast(struct cpumask *mask) 168 static void tick_do_broadcast(struct cpumask *mask)
168 { 169 {
169 int cpu = smp_processor_id(); 170 int cpu = smp_processor_id();
170 struct tick_device *td; 171 struct tick_device *td;
171 172
172 /* 173 /*
173 * Check, if the current cpu is in the mask 174 * Check, if the current cpu is in the mask
174 */ 175 */
175 if (cpumask_test_cpu(cpu, mask)) { 176 if (cpumask_test_cpu(cpu, mask)) {
176 cpumask_clear_cpu(cpu, mask); 177 cpumask_clear_cpu(cpu, mask);
177 td = &per_cpu(tick_cpu_device, cpu); 178 td = &per_cpu(tick_cpu_device, cpu);
178 td->evtdev->event_handler(td->evtdev); 179 td->evtdev->event_handler(td->evtdev);
179 } 180 }
180 181
181 if (!cpumask_empty(mask)) { 182 if (!cpumask_empty(mask)) {
182 /* 183 /*
183 * It might be necessary to actually check whether the devices 184 * It might be necessary to actually check whether the devices
184 * have different broadcast functions. For now, just use the 185 * have different broadcast functions. For now, just use the
185 * one of the first device. This works as long as we have this 186 * one of the first device. This works as long as we have this
186 * misfeature only on x86 (lapic) 187 * misfeature only on x86 (lapic)
187 */ 188 */
188 td = &per_cpu(tick_cpu_device, cpumask_first(mask)); 189 td = &per_cpu(tick_cpu_device, cpumask_first(mask));
189 td->evtdev->broadcast(mask); 190 td->evtdev->broadcast(mask);
190 } 191 }
191 } 192 }
192 193
193 /* 194 /*
194 * Periodic broadcast: 195 * Periodic broadcast:
195 * - invoke the broadcast handlers 196 * - invoke the broadcast handlers
196 */ 197 */
197 static void tick_do_periodic_broadcast(void) 198 static void tick_do_periodic_broadcast(void)
198 { 199 {
199 raw_spin_lock(&tick_broadcast_lock); 200 raw_spin_lock(&tick_broadcast_lock);
200 201
201 cpumask_and(to_cpumask(tmpmask), 202 cpumask_and(to_cpumask(tmpmask),
202 cpu_online_mask, tick_get_broadcast_mask()); 203 cpu_online_mask, tick_get_broadcast_mask());
203 tick_do_broadcast(to_cpumask(tmpmask)); 204 tick_do_broadcast(to_cpumask(tmpmask));
204 205
205 raw_spin_unlock(&tick_broadcast_lock); 206 raw_spin_unlock(&tick_broadcast_lock);
206 } 207 }
207 208
208 /* 209 /*
209 * Event handler for periodic broadcast ticks 210 * Event handler for periodic broadcast ticks
210 */ 211 */
211 static void tick_handle_periodic_broadcast(struct clock_event_device *dev) 212 static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
212 { 213 {
213 ktime_t next; 214 ktime_t next;
214 215
215 tick_do_periodic_broadcast(); 216 tick_do_periodic_broadcast();
216 217
217 /* 218 /*
218 * The device is in periodic mode. No reprogramming necessary: 219 * The device is in periodic mode. No reprogramming necessary:
219 */ 220 */
220 if (dev->mode == CLOCK_EVT_MODE_PERIODIC) 221 if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
221 return; 222 return;
222 223
223 /* 224 /*
224 * Setup the next period for devices, which do not have 225 * Setup the next period for devices, which do not have
225 * periodic mode. We read dev->next_event first and add to it 226 * periodic mode. We read dev->next_event first and add to it
226 * when the event already expired. clockevents_program_event() 227 * when the event already expired. clockevents_program_event()
227 * sets dev->next_event only when the event is really 228 * sets dev->next_event only when the event is really
228 * programmed to the device. 229 * programmed to the device.
229 */ 230 */
230 for (next = dev->next_event; ;) { 231 for (next = dev->next_event; ;) {
231 next = ktime_add(next, tick_period); 232 next = ktime_add(next, tick_period);
232 233
233 if (!clockevents_program_event(dev, next, false)) 234 if (!clockevents_program_event(dev, next, false))
234 return; 235 return;
235 tick_do_periodic_broadcast(); 236 tick_do_periodic_broadcast();
236 } 237 }
237 } 238 }
238 239
239 /* 240 /*
240 * Powerstate information: The system enters/leaves a state, where 241 * Powerstate information: The system enters/leaves a state, where
241 * affected devices might stop 242 * affected devices might stop
242 */ 243 */
243 static void tick_do_broadcast_on_off(unsigned long *reason) 244 static void tick_do_broadcast_on_off(unsigned long *reason)
244 { 245 {
245 struct clock_event_device *bc, *dev; 246 struct clock_event_device *bc, *dev;
246 struct tick_device *td; 247 struct tick_device *td;
247 unsigned long flags; 248 unsigned long flags;
248 int cpu, bc_stopped; 249 int cpu, bc_stopped;
249 250
250 raw_spin_lock_irqsave(&tick_broadcast_lock, flags); 251 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
251 252
252 cpu = smp_processor_id(); 253 cpu = smp_processor_id();
253 td = &per_cpu(tick_cpu_device, cpu); 254 td = &per_cpu(tick_cpu_device, cpu);
254 dev = td->evtdev; 255 dev = td->evtdev;
255 bc = tick_broadcast_device.evtdev; 256 bc = tick_broadcast_device.evtdev;
256 257
257 /* 258 /*
258 * Is the device not affected by the powerstate ? 259 * Is the device not affected by the powerstate ?
259 */ 260 */
260 if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP)) 261 if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
261 goto out; 262 goto out;
262 263
263 if (!tick_device_is_functional(dev)) 264 if (!tick_device_is_functional(dev))
264 goto out; 265 goto out;
265 266
266 bc_stopped = cpumask_empty(tick_get_broadcast_mask()); 267 bc_stopped = cpumask_empty(tick_get_broadcast_mask());
267 268
268 switch (*reason) { 269 switch (*reason) {
269 case CLOCK_EVT_NOTIFY_BROADCAST_ON: 270 case CLOCK_EVT_NOTIFY_BROADCAST_ON:
270 case CLOCK_EVT_NOTIFY_BROADCAST_FORCE: 271 case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
271 if (!cpumask_test_cpu(cpu, tick_get_broadcast_mask())) { 272 if (!cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
272 cpumask_set_cpu(cpu, tick_get_broadcast_mask()); 273 cpumask_set_cpu(cpu, tick_get_broadcast_mask());
273 if (tick_broadcast_device.mode == 274 if (tick_broadcast_device.mode ==
274 TICKDEV_MODE_PERIODIC) 275 TICKDEV_MODE_PERIODIC)
275 clockevents_shutdown(dev); 276 clockevents_shutdown(dev);
276 } 277 }
277 if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE) 278 if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
278 tick_broadcast_force = 1; 279 tick_broadcast_force = 1;
279 break; 280 break;
280 case CLOCK_EVT_NOTIFY_BROADCAST_OFF: 281 case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
281 if (!tick_broadcast_force && 282 if (!tick_broadcast_force &&
282 cpumask_test_cpu(cpu, tick_get_broadcast_mask())) { 283 cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
283 cpumask_clear_cpu(cpu, tick_get_broadcast_mask()); 284 cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
284 if (tick_broadcast_device.mode == 285 if (tick_broadcast_device.mode ==
285 TICKDEV_MODE_PERIODIC) 286 TICKDEV_MODE_PERIODIC)
286 tick_setup_periodic(dev, 0); 287 tick_setup_periodic(dev, 0);
287 } 288 }
288 break; 289 break;
289 } 290 }
290 291
291 if (cpumask_empty(tick_get_broadcast_mask())) { 292 if (cpumask_empty(tick_get_broadcast_mask())) {
292 if (!bc_stopped) 293 if (!bc_stopped)
293 clockevents_shutdown(bc); 294 clockevents_shutdown(bc);
294 } else if (bc_stopped) { 295 } else if (bc_stopped) {
295 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) 296 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
296 tick_broadcast_start_periodic(bc); 297 tick_broadcast_start_periodic(bc);
297 else 298 else
298 tick_broadcast_setup_oneshot(bc); 299 tick_broadcast_setup_oneshot(bc);
299 } 300 }
300 out: 301 out:
301 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); 302 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
302 } 303 }
303 304
304 /* 305 /*
305 * Powerstate information: The system enters/leaves a state, where 306 * Powerstate information: The system enters/leaves a state, where
306 * affected devices might stop. 307 * affected devices might stop.
307 */ 308 */
308 void tick_broadcast_on_off(unsigned long reason, int *oncpu) 309 void tick_broadcast_on_off(unsigned long reason, int *oncpu)
309 { 310 {
310 if (!cpumask_test_cpu(*oncpu, cpu_online_mask)) 311 if (!cpumask_test_cpu(*oncpu, cpu_online_mask))
311 printk(KERN_ERR "tick-broadcast: ignoring broadcast for " 312 printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
312 "offline CPU #%d\n", *oncpu); 313 "offline CPU #%d\n", *oncpu);
313 else 314 else
314 tick_do_broadcast_on_off(&reason); 315 tick_do_broadcast_on_off(&reason);
315 } 316 }
316 317
317 /* 318 /*
318 * Set the periodic handler depending on broadcast on/off 319 * Set the periodic handler depending on broadcast on/off
319 */ 320 */
320 void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast) 321 void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
321 { 322 {
322 if (!broadcast) 323 if (!broadcast)
323 dev->event_handler = tick_handle_periodic; 324 dev->event_handler = tick_handle_periodic;
324 else 325 else
325 dev->event_handler = tick_handle_periodic_broadcast; 326 dev->event_handler = tick_handle_periodic_broadcast;
326 } 327 }
327 328
328 /* 329 /*
329 * Remove a CPU from broadcasting 330 * Remove a CPU from broadcasting
330 */ 331 */
331 void tick_shutdown_broadcast(unsigned int *cpup) 332 void tick_shutdown_broadcast(unsigned int *cpup)
332 { 333 {
333 struct clock_event_device *bc; 334 struct clock_event_device *bc;
334 unsigned long flags; 335 unsigned long flags;
335 unsigned int cpu = *cpup; 336 unsigned int cpu = *cpup;
336 337
337 raw_spin_lock_irqsave(&tick_broadcast_lock, flags); 338 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
338 339
339 bc = tick_broadcast_device.evtdev; 340 bc = tick_broadcast_device.evtdev;
340 cpumask_clear_cpu(cpu, tick_get_broadcast_mask()); 341 cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
341 342
342 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) { 343 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
343 if (bc && cpumask_empty(tick_get_broadcast_mask())) 344 if (bc && cpumask_empty(tick_get_broadcast_mask()))
344 clockevents_shutdown(bc); 345 clockevents_shutdown(bc);
345 } 346 }
346 347
347 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); 348 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
348 } 349 }
349 350
350 void tick_suspend_broadcast(void) 351 void tick_suspend_broadcast(void)
351 { 352 {
352 struct clock_event_device *bc; 353 struct clock_event_device *bc;
353 unsigned long flags; 354 unsigned long flags;
354 355
355 raw_spin_lock_irqsave(&tick_broadcast_lock, flags); 356 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
356 357
357 bc = tick_broadcast_device.evtdev; 358 bc = tick_broadcast_device.evtdev;
358 if (bc) 359 if (bc)
359 clockevents_shutdown(bc); 360 clockevents_shutdown(bc);
360 361
361 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); 362 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
362 } 363 }
363 364
364 int tick_resume_broadcast(void) 365 int tick_resume_broadcast(void)
365 { 366 {
366 struct clock_event_device *bc; 367 struct clock_event_device *bc;
367 unsigned long flags; 368 unsigned long flags;
368 int broadcast = 0; 369 int broadcast = 0;
369 370
370 raw_spin_lock_irqsave(&tick_broadcast_lock, flags); 371 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
371 372
372 bc = tick_broadcast_device.evtdev; 373 bc = tick_broadcast_device.evtdev;
373 374
374 if (bc) { 375 if (bc) {
375 clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME); 376 clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
376 377
377 switch (tick_broadcast_device.mode) { 378 switch (tick_broadcast_device.mode) {
378 case TICKDEV_MODE_PERIODIC: 379 case TICKDEV_MODE_PERIODIC:
379 if (!cpumask_empty(tick_get_broadcast_mask())) 380 if (!cpumask_empty(tick_get_broadcast_mask()))
380 tick_broadcast_start_periodic(bc); 381 tick_broadcast_start_periodic(bc);
381 broadcast = cpumask_test_cpu(smp_processor_id(), 382 broadcast = cpumask_test_cpu(smp_processor_id(),
382 tick_get_broadcast_mask()); 383 tick_get_broadcast_mask());
383 break; 384 break;
384 case TICKDEV_MODE_ONESHOT: 385 case TICKDEV_MODE_ONESHOT:
385 if (!cpumask_empty(tick_get_broadcast_mask())) 386 if (!cpumask_empty(tick_get_broadcast_mask()))
386 broadcast = tick_resume_broadcast_oneshot(bc); 387 broadcast = tick_resume_broadcast_oneshot(bc);
387 break; 388 break;
388 } 389 }
389 } 390 }
390 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); 391 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
391 392
392 return broadcast; 393 return broadcast;
393 } 394 }
394 395
395 396
396 #ifdef CONFIG_TICK_ONESHOT 397 #ifdef CONFIG_TICK_ONESHOT
397 398
398 /* FIXME: use cpumask_var_t. */ 399 /* FIXME: use cpumask_var_t. */
399 static DECLARE_BITMAP(tick_broadcast_oneshot_mask, NR_CPUS); 400 static DECLARE_BITMAP(tick_broadcast_oneshot_mask, NR_CPUS);
400 401
401 /* 402 /*
402 * Exposed for debugging: see timer_list.c 403 * Exposed for debugging: see timer_list.c
403 */ 404 */
404 struct cpumask *tick_get_broadcast_oneshot_mask(void) 405 struct cpumask *tick_get_broadcast_oneshot_mask(void)
405 { 406 {
406 return to_cpumask(tick_broadcast_oneshot_mask); 407 return to_cpumask(tick_broadcast_oneshot_mask);
407 } 408 }
408 409
409 static int tick_broadcast_set_event(ktime_t expires, int force) 410 static int tick_broadcast_set_event(ktime_t expires, int force)
410 { 411 {
411 struct clock_event_device *bc = tick_broadcast_device.evtdev; 412 struct clock_event_device *bc = tick_broadcast_device.evtdev;
412 413
413 if (bc->mode != CLOCK_EVT_MODE_ONESHOT) 414 if (bc->mode != CLOCK_EVT_MODE_ONESHOT)
414 clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); 415 clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
415 416
416 return clockevents_program_event(bc, expires, force); 417 return clockevents_program_event(bc, expires, force);
417 } 418 }
418 419
419 int tick_resume_broadcast_oneshot(struct clock_event_device *bc) 420 int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
420 { 421 {
421 clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); 422 clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
422 return 0; 423 return 0;
423 } 424 }
424 425
425 /* 426 /*
426 * Called from irq_enter() when idle was interrupted to reenable the 427 * Called from irq_enter() when idle was interrupted to reenable the
427 * per cpu device. 428 * per cpu device.
428 */ 429 */
429 void tick_check_oneshot_broadcast(int cpu) 430 void tick_check_oneshot_broadcast(int cpu)
430 { 431 {
431 if (cpumask_test_cpu(cpu, to_cpumask(tick_broadcast_oneshot_mask))) { 432 if (cpumask_test_cpu(cpu, to_cpumask(tick_broadcast_oneshot_mask))) {
432 struct tick_device *td = &per_cpu(tick_cpu_device, cpu); 433 struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
433 434
434 clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT); 435 clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT);
435 } 436 }
436 } 437 }
437 438
438 /* 439 /*
439 * Handle oneshot mode broadcasting 440 * Handle oneshot mode broadcasting
440 */ 441 */
441 static void tick_handle_oneshot_broadcast(struct clock_event_device *dev) 442 static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
442 { 443 {
443 struct tick_device *td; 444 struct tick_device *td;
444 ktime_t now, next_event; 445 ktime_t now, next_event;
445 int cpu; 446 int cpu;
446 447
447 raw_spin_lock(&tick_broadcast_lock); 448 raw_spin_lock(&tick_broadcast_lock);
448 again: 449 again:
449 dev->next_event.tv64 = KTIME_MAX; 450 dev->next_event.tv64 = KTIME_MAX;
450 next_event.tv64 = KTIME_MAX; 451 next_event.tv64 = KTIME_MAX;
451 cpumask_clear(to_cpumask(tmpmask)); 452 cpumask_clear(to_cpumask(tmpmask));
452 now = ktime_get(); 453 now = ktime_get();
453 /* Find all expired events */ 454 /* Find all expired events */
454 for_each_cpu(cpu, tick_get_broadcast_oneshot_mask()) { 455 for_each_cpu(cpu, tick_get_broadcast_oneshot_mask()) {
455 td = &per_cpu(tick_cpu_device, cpu); 456 td = &per_cpu(tick_cpu_device, cpu);
456 if (td->evtdev->next_event.tv64 <= now.tv64) 457 if (td->evtdev->next_event.tv64 <= now.tv64)
457 cpumask_set_cpu(cpu, to_cpumask(tmpmask)); 458 cpumask_set_cpu(cpu, to_cpumask(tmpmask));
458 else if (td->evtdev->next_event.tv64 < next_event.tv64) 459 else if (td->evtdev->next_event.tv64 < next_event.tv64)
459 next_event.tv64 = td->evtdev->next_event.tv64; 460 next_event.tv64 = td->evtdev->next_event.tv64;
460 } 461 }
461 462
462 /* 463 /*
463 * Wakeup the cpus which have an expired event. 464 * Wakeup the cpus which have an expired event.
464 */ 465 */
465 tick_do_broadcast(to_cpumask(tmpmask)); 466 tick_do_broadcast(to_cpumask(tmpmask));
466 467
467 /* 468 /*
468 * Two reasons for reprogram: 469 * Two reasons for reprogram:
469 * 470 *
470 * - The global event did not expire any CPU local 471 * - The global event did not expire any CPU local
471 * events. This happens in dyntick mode, as the maximum PIT 472 * events. This happens in dyntick mode, as the maximum PIT
472 * delta is quite small. 473 * delta is quite small.
473 * 474 *
474 * - There are pending events on sleeping CPUs which were not 475 * - There are pending events on sleeping CPUs which were not
475 * in the event mask 476 * in the event mask
476 */ 477 */
477 if (next_event.tv64 != KTIME_MAX) { 478 if (next_event.tv64 != KTIME_MAX) {
478 /* 479 /*
479 * Rearm the broadcast device. If event expired, 480 * Rearm the broadcast device. If event expired,
480 * repeat the above 481 * repeat the above
481 */ 482 */
482 if (tick_broadcast_set_event(next_event, 0)) 483 if (tick_broadcast_set_event(next_event, 0))
483 goto again; 484 goto again;
484 } 485 }
485 raw_spin_unlock(&tick_broadcast_lock); 486 raw_spin_unlock(&tick_broadcast_lock);
486 } 487 }
487 488
488 /* 489 /*
489 * Powerstate information: The system enters/leaves a state, where 490 * Powerstate information: The system enters/leaves a state, where
490 * affected devices might stop 491 * affected devices might stop
491 */ 492 */
492 void tick_broadcast_oneshot_control(unsigned long reason) 493 void tick_broadcast_oneshot_control(unsigned long reason)
493 { 494 {
494 struct clock_event_device *bc, *dev; 495 struct clock_event_device *bc, *dev;
495 struct tick_device *td; 496 struct tick_device *td;
496 unsigned long flags; 497 unsigned long flags;
497 int cpu; 498 int cpu;
498 499
499 /* 500 /*
500 * Periodic mode does not care about the enter/exit of power 501 * Periodic mode does not care about the enter/exit of power
501 * states 502 * states
502 */ 503 */
503 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) 504 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
504 return; 505 return;
505 506
506 /* 507 /*
507 * We are called with preemtion disabled from the depth of the 508 * We are called with preemtion disabled from the depth of the
508 * idle code, so we can't be moved away. 509 * idle code, so we can't be moved away.
509 */ 510 */
510 cpu = smp_processor_id(); 511 cpu = smp_processor_id();
511 td = &per_cpu(tick_cpu_device, cpu); 512 td = &per_cpu(tick_cpu_device, cpu);
512 dev = td->evtdev; 513 dev = td->evtdev;
513 514
514 if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) 515 if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
515 return; 516 return;
516 517
517 bc = tick_broadcast_device.evtdev; 518 bc = tick_broadcast_device.evtdev;
518 519
519 raw_spin_lock_irqsave(&tick_broadcast_lock, flags); 520 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
520 if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) { 521 if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
521 if (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) { 522 if (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
522 cpumask_set_cpu(cpu, tick_get_broadcast_oneshot_mask()); 523 cpumask_set_cpu(cpu, tick_get_broadcast_oneshot_mask());
523 clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN); 524 clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
524 if (dev->next_event.tv64 < bc->next_event.tv64) 525 if (dev->next_event.tv64 < bc->next_event.tv64)
525 tick_broadcast_set_event(dev->next_event, 1); 526 tick_broadcast_set_event(dev->next_event, 1);
526 } 527 }
527 } else { 528 } else {
528 if (cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) { 529 if (cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
529 cpumask_clear_cpu(cpu, 530 cpumask_clear_cpu(cpu,
530 tick_get_broadcast_oneshot_mask()); 531 tick_get_broadcast_oneshot_mask());
531 clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT); 532 clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
532 if (dev->next_event.tv64 != KTIME_MAX) 533 if (dev->next_event.tv64 != KTIME_MAX)
533 tick_program_event(dev->next_event, 1); 534 tick_program_event(dev->next_event, 1);
534 } 535 }
535 } 536 }
536 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); 537 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
537 } 538 }
538 539
539 /* 540 /*
540 * Reset the one shot broadcast for a cpu 541 * Reset the one shot broadcast for a cpu
541 * 542 *
542 * Called with tick_broadcast_lock held 543 * Called with tick_broadcast_lock held
543 */ 544 */
544 static void tick_broadcast_clear_oneshot(int cpu) 545 static void tick_broadcast_clear_oneshot(int cpu)
545 { 546 {
546 cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask()); 547 cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
547 } 548 }
548 549
549 static void tick_broadcast_init_next_event(struct cpumask *mask, 550 static void tick_broadcast_init_next_event(struct cpumask *mask,
550 ktime_t expires) 551 ktime_t expires)
551 { 552 {
552 struct tick_device *td; 553 struct tick_device *td;
553 int cpu; 554 int cpu;
554 555
555 for_each_cpu(cpu, mask) { 556 for_each_cpu(cpu, mask) {
556 td = &per_cpu(tick_cpu_device, cpu); 557 td = &per_cpu(tick_cpu_device, cpu);
557 if (td->evtdev) 558 if (td->evtdev)
558 td->evtdev->next_event = expires; 559 td->evtdev->next_event = expires;
559 } 560 }
560 } 561 }
561 562
562 /** 563 /**
563 * tick_broadcast_setup_oneshot - setup the broadcast device 564 * tick_broadcast_setup_oneshot - setup the broadcast device
564 */ 565 */
565 void tick_broadcast_setup_oneshot(struct clock_event_device *bc) 566 void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
566 { 567 {
567 int cpu = smp_processor_id(); 568 int cpu = smp_processor_id();
568 569
569 /* Set it up only once ! */ 570 /* Set it up only once ! */
570 if (bc->event_handler != tick_handle_oneshot_broadcast) { 571 if (bc->event_handler != tick_handle_oneshot_broadcast) {
571 int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC; 572 int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
572 573
573 bc->event_handler = tick_handle_oneshot_broadcast; 574 bc->event_handler = tick_handle_oneshot_broadcast;
574 575
575 /* Take the do_timer update */ 576 /* Take the do_timer update */
576 tick_do_timer_cpu = cpu; 577 tick_do_timer_cpu = cpu;
577 578
578 /* 579 /*
579 * We must be careful here. There might be other CPUs 580 * We must be careful here. There might be other CPUs
580 * waiting for periodic broadcast. We need to set the 581 * waiting for periodic broadcast. We need to set the
581 * oneshot_mask bits for those and program the 582 * oneshot_mask bits for those and program the
582 * broadcast device to fire. 583 * broadcast device to fire.
583 */ 584 */
584 cpumask_copy(to_cpumask(tmpmask), tick_get_broadcast_mask()); 585 cpumask_copy(to_cpumask(tmpmask), tick_get_broadcast_mask());
585 cpumask_clear_cpu(cpu, to_cpumask(tmpmask)); 586 cpumask_clear_cpu(cpu, to_cpumask(tmpmask));
586 cpumask_or(tick_get_broadcast_oneshot_mask(), 587 cpumask_or(tick_get_broadcast_oneshot_mask(),
587 tick_get_broadcast_oneshot_mask(), 588 tick_get_broadcast_oneshot_mask(),
588 to_cpumask(tmpmask)); 589 to_cpumask(tmpmask));
589 590
590 if (was_periodic && !cpumask_empty(to_cpumask(tmpmask))) { 591 if (was_periodic && !cpumask_empty(to_cpumask(tmpmask))) {
591 clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); 592 clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
592 tick_broadcast_init_next_event(to_cpumask(tmpmask), 593 tick_broadcast_init_next_event(to_cpumask(tmpmask),
593 tick_next_period); 594 tick_next_period);
594 tick_broadcast_set_event(tick_next_period, 1); 595 tick_broadcast_set_event(tick_next_period, 1);
595 } else 596 } else
596 bc->next_event.tv64 = KTIME_MAX; 597 bc->next_event.tv64 = KTIME_MAX;
597 } else { 598 } else {
598 /* 599 /*
599 * The first cpu which switches to oneshot mode sets 600 * The first cpu which switches to oneshot mode sets
600 * the bit for all other cpus which are in the general 601 * the bit for all other cpus which are in the general
601 * (periodic) broadcast mask. So the bit is set and 602 * (periodic) broadcast mask. So the bit is set and
602 * would prevent the first broadcast enter after this 603 * would prevent the first broadcast enter after this
603 * to program the bc device. 604 * to program the bc device.
604 */ 605 */
605 tick_broadcast_clear_oneshot(cpu); 606 tick_broadcast_clear_oneshot(cpu);
606 } 607 }
607 } 608 }
608 609
609 /* 610 /*
610 * Select oneshot operating mode for the broadcast device 611 * Select oneshot operating mode for the broadcast device
611 */ 612 */
612 void tick_broadcast_switch_to_oneshot(void) 613 void tick_broadcast_switch_to_oneshot(void)
613 { 614 {
614 struct clock_event_device *bc; 615 struct clock_event_device *bc;
615 unsigned long flags; 616 unsigned long flags;
616 617
617 raw_spin_lock_irqsave(&tick_broadcast_lock, flags); 618 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
618 619
619 tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT; 620 tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
620 bc = tick_broadcast_device.evtdev; 621 bc = tick_broadcast_device.evtdev;
621 if (bc) 622 if (bc)
622 tick_broadcast_setup_oneshot(bc); 623 tick_broadcast_setup_oneshot(bc);
623 624
624 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); 625 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
625 } 626 }
626 627
627 628
628 /* 629 /*
629 * Remove a dead CPU from broadcasting 630 * Remove a dead CPU from broadcasting
630 */ 631 */
631 void tick_shutdown_broadcast_oneshot(unsigned int *cpup) 632 void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
632 { 633 {
633 unsigned long flags; 634 unsigned long flags;
634 unsigned int cpu = *cpup; 635 unsigned int cpu = *cpup;
635 636
636 raw_spin_lock_irqsave(&tick_broadcast_lock, flags); 637 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
637 638
638 /* 639 /*
639 * Clear the broadcast mask flag for the dead cpu, but do not 640 * Clear the broadcast mask flag for the dead cpu, but do not
640 * stop the broadcast device! 641 * stop the broadcast device!
641 */ 642 */
642 cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask()); 643 cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
643 644
644 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); 645 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
645 } 646 }
646 647
647 /* 648 /*
648 * Check, whether the broadcast device is in one shot mode 649 * Check, whether the broadcast device is in one shot mode
649 */ 650 */
650 int tick_broadcast_oneshot_active(void) 651 int tick_broadcast_oneshot_active(void)
651 { 652 {
652 return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT; 653 return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
653 } 654 }
654 655
655 /* 656 /*
656 * Check whether the broadcast device supports oneshot. 657 * Check whether the broadcast device supports oneshot.
657 */ 658 */
658 bool tick_broadcast_oneshot_available(void) 659 bool tick_broadcast_oneshot_available(void)
659 { 660 {
660 struct clock_event_device *bc = tick_broadcast_device.evtdev; 661 struct clock_event_device *bc = tick_broadcast_device.evtdev;
661 662
662 return bc ? bc->features & CLOCK_EVT_FEAT_ONESHOT : false; 663 return bc ? bc->features & CLOCK_EVT_FEAT_ONESHOT : false;
663 } 664 }
664 665
665 #endif 666 #endif
666 667