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Commit | Line | Data |
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15c84731 JF |
1 | /* |
2 | * Xen time implementation. | |
3 | * | |
4 | * This is implemented in terms of a clocksource driver which uses | |
5 | * the hypervisor clock as a nanosecond timebase, and a clockevent | |
6 | * driver which uses the hypervisor's timer mechanism. | |
7 | * | |
8 | * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 | |
9 | */ | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/clocksource.h> | |
13 | #include <linux/clockchips.h> | |
f91a8b44 | 14 | #include <linux/kernel_stat.h> |
15c84731 JF |
15 | |
16 | #include <asm/xen/hypervisor.h> | |
17 | #include <asm/xen/hypercall.h> | |
18 | ||
19 | #include <xen/events.h> | |
20 | #include <xen/interface/xen.h> | |
21 | #include <xen/interface/vcpu.h> | |
22 | ||
23 | #include "xen-ops.h" | |
24 | ||
25 | #define XEN_SHIFT 22 | |
26 | ||
27 | /* Xen may fire a timer up to this many ns early */ | |
28 | #define TIMER_SLOP 100000 | |
f91a8b44 | 29 | #define NS_PER_TICK (1000000000LL / HZ) |
15c84731 | 30 | |
ab550288 JF |
31 | static cycle_t xen_clocksource_read(void); |
32 | ||
15c84731 JF |
33 | /* These are perodically updated in shared_info, and then copied here. */ |
34 | struct shadow_time_info { | |
35 | u64 tsc_timestamp; /* TSC at last update of time vals. */ | |
36 | u64 system_timestamp; /* Time, in nanosecs, since boot. */ | |
37 | u32 tsc_to_nsec_mul; | |
38 | int tsc_shift; | |
39 | u32 version; | |
40 | }; | |
41 | ||
42 | static DEFINE_PER_CPU(struct shadow_time_info, shadow_time); | |
43 | ||
f91a8b44 JF |
44 | /* runstate info updated by Xen */ |
45 | static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate); | |
46 | ||
47 | /* snapshots of runstate info */ | |
48 | static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate_snapshot); | |
49 | ||
50 | /* unused ns of stolen and blocked time */ | |
51 | static DEFINE_PER_CPU(u64, residual_stolen); | |
52 | static DEFINE_PER_CPU(u64, residual_blocked); | |
53 | ||
54 | /* return an consistent snapshot of 64-bit time/counter value */ | |
55 | static u64 get64(const u64 *p) | |
56 | { | |
57 | u64 ret; | |
58 | ||
59 | if (BITS_PER_LONG < 64) { | |
60 | u32 *p32 = (u32 *)p; | |
61 | u32 h, l; | |
62 | ||
63 | /* | |
64 | * Read high then low, and then make sure high is | |
65 | * still the same; this will only loop if low wraps | |
66 | * and carries into high. | |
67 | * XXX some clean way to make this endian-proof? | |
68 | */ | |
69 | do { | |
70 | h = p32[1]; | |
71 | barrier(); | |
72 | l = p32[0]; | |
73 | barrier(); | |
74 | } while (p32[1] != h); | |
75 | ||
76 | ret = (((u64)h) << 32) | l; | |
77 | } else | |
78 | ret = *p; | |
79 | ||
80 | return ret; | |
81 | } | |
82 | ||
83 | /* | |
84 | * Runstate accounting | |
85 | */ | |
86 | static void get_runstate_snapshot(struct vcpu_runstate_info *res) | |
87 | { | |
88 | u64 state_time; | |
89 | struct vcpu_runstate_info *state; | |
90 | ||
f120f13e | 91 | BUG_ON(preemptible()); |
f91a8b44 JF |
92 | |
93 | state = &__get_cpu_var(runstate); | |
94 | ||
95 | /* | |
96 | * The runstate info is always updated by the hypervisor on | |
97 | * the current CPU, so there's no need to use anything | |
98 | * stronger than a compiler barrier when fetching it. | |
99 | */ | |
100 | do { | |
101 | state_time = get64(&state->state_entry_time); | |
102 | barrier(); | |
103 | *res = *state; | |
104 | barrier(); | |
105 | } while (get64(&state->state_entry_time) != state_time); | |
f91a8b44 JF |
106 | } |
107 | ||
f0d73394 JF |
108 | /* return true when a vcpu could run but has no real cpu to run on */ |
109 | bool xen_vcpu_stolen(int vcpu) | |
110 | { | |
111 | return per_cpu(runstate, vcpu).state == RUNSTATE_runnable; | |
112 | } | |
113 | ||
f91a8b44 JF |
114 | static void setup_runstate_info(int cpu) |
115 | { | |
116 | struct vcpu_register_runstate_memory_area area; | |
117 | ||
118 | area.addr.v = &per_cpu(runstate, cpu); | |
119 | ||
120 | if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area, | |
121 | cpu, &area)) | |
122 | BUG(); | |
123 | } | |
124 | ||
125 | static void do_stolen_accounting(void) | |
126 | { | |
127 | struct vcpu_runstate_info state; | |
128 | struct vcpu_runstate_info *snap; | |
129 | s64 blocked, runnable, offline, stolen; | |
130 | cputime_t ticks; | |
131 | ||
132 | get_runstate_snapshot(&state); | |
133 | ||
134 | WARN_ON(state.state != RUNSTATE_running); | |
135 | ||
136 | snap = &__get_cpu_var(runstate_snapshot); | |
137 | ||
138 | /* work out how much time the VCPU has not been runn*ing* */ | |
139 | blocked = state.time[RUNSTATE_blocked] - snap->time[RUNSTATE_blocked]; | |
140 | runnable = state.time[RUNSTATE_runnable] - snap->time[RUNSTATE_runnable]; | |
141 | offline = state.time[RUNSTATE_offline] - snap->time[RUNSTATE_offline]; | |
142 | ||
143 | *snap = state; | |
144 | ||
145 | /* Add the appropriate number of ticks of stolen time, | |
146 | including any left-overs from last time. Passing NULL to | |
147 | account_steal_time accounts the time as stolen. */ | |
148 | stolen = runnable + offline + __get_cpu_var(residual_stolen); | |
149 | ||
150 | if (stolen < 0) | |
151 | stolen = 0; | |
152 | ||
153 | ticks = 0; | |
154 | while (stolen >= NS_PER_TICK) { | |
155 | ticks++; | |
156 | stolen -= NS_PER_TICK; | |
157 | } | |
158 | __get_cpu_var(residual_stolen) = stolen; | |
159 | account_steal_time(NULL, ticks); | |
160 | ||
161 | /* Add the appropriate number of ticks of blocked time, | |
162 | including any left-overs from last time. Passing idle to | |
163 | account_steal_time accounts the time as idle/wait. */ | |
164 | blocked += __get_cpu_var(residual_blocked); | |
165 | ||
166 | if (blocked < 0) | |
167 | blocked = 0; | |
168 | ||
169 | ticks = 0; | |
170 | while (blocked >= NS_PER_TICK) { | |
171 | ticks++; | |
172 | blocked -= NS_PER_TICK; | |
173 | } | |
174 | __get_cpu_var(residual_blocked) = blocked; | |
175 | account_steal_time(idle_task(smp_processor_id()), ticks); | |
176 | } | |
177 | ||
ab550288 JF |
178 | /* |
179 | * Xen sched_clock implementation. Returns the number of unstolen | |
180 | * nanoseconds, which is nanoseconds the VCPU spent in RUNNING+BLOCKED | |
181 | * states. | |
182 | */ | |
183 | unsigned long long xen_sched_clock(void) | |
184 | { | |
185 | struct vcpu_runstate_info state; | |
f120f13e JF |
186 | cycle_t now; |
187 | u64 ret; | |
ab550288 JF |
188 | s64 offset; |
189 | ||
f120f13e JF |
190 | /* |
191 | * Ideally sched_clock should be called on a per-cpu basis | |
192 | * anyway, so preempt should already be disabled, but that's | |
193 | * not current practice at the moment. | |
194 | */ | |
195 | preempt_disable(); | |
196 | ||
197 | now = xen_clocksource_read(); | |
198 | ||
ab550288 JF |
199 | get_runstate_snapshot(&state); |
200 | ||
201 | WARN_ON(state.state != RUNSTATE_running); | |
202 | ||
203 | offset = now - state.state_entry_time; | |
204 | if (offset < 0) | |
205 | offset = 0; | |
206 | ||
f120f13e | 207 | ret = state.time[RUNSTATE_blocked] + |
ab550288 JF |
208 | state.time[RUNSTATE_running] + |
209 | offset; | |
f120f13e JF |
210 | |
211 | preempt_enable(); | |
212 | ||
213 | return ret; | |
ab550288 | 214 | } |
f91a8b44 JF |
215 | |
216 | ||
217 | /* Get the CPU speed from Xen */ | |
15c84731 JF |
218 | unsigned long xen_cpu_khz(void) |
219 | { | |
88a5ac89 | 220 | u64 xen_khz = 1000000ULL << 32; |
15c84731 JF |
221 | const struct vcpu_time_info *info = |
222 | &HYPERVISOR_shared_info->vcpu_info[0].time; | |
223 | ||
88a5ac89 | 224 | do_div(xen_khz, info->tsc_to_system_mul); |
15c84731 | 225 | if (info->tsc_shift < 0) |
88a5ac89 | 226 | xen_khz <<= -info->tsc_shift; |
15c84731 | 227 | else |
88a5ac89 | 228 | xen_khz >>= info->tsc_shift; |
15c84731 | 229 | |
88a5ac89 | 230 | return xen_khz; |
15c84731 JF |
231 | } |
232 | ||
233 | /* | |
234 | * Reads a consistent set of time-base values from Xen, into a shadow data | |
235 | * area. | |
236 | */ | |
f91a8b44 | 237 | static unsigned get_time_values_from_xen(void) |
15c84731 JF |
238 | { |
239 | struct vcpu_time_info *src; | |
240 | struct shadow_time_info *dst; | |
241 | ||
15c84731 JF |
242 | /* src is shared memory with the hypervisor, so we need to |
243 | make sure we get a consistent snapshot, even in the face of | |
244 | being preempted. */ | |
245 | src = &__get_cpu_var(xen_vcpu)->time; | |
246 | dst = &__get_cpu_var(shadow_time); | |
247 | ||
248 | do { | |
249 | dst->version = src->version; | |
250 | rmb(); /* fetch version before data */ | |
251 | dst->tsc_timestamp = src->tsc_timestamp; | |
252 | dst->system_timestamp = src->system_time; | |
253 | dst->tsc_to_nsec_mul = src->tsc_to_system_mul; | |
254 | dst->tsc_shift = src->tsc_shift; | |
255 | rmb(); /* test version after fetching data */ | |
256 | } while ((src->version & 1) | (dst->version ^ src->version)); | |
257 | ||
f91a8b44 | 258 | return dst->version; |
15c84731 JF |
259 | } |
260 | ||
261 | /* | |
262 | * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction, | |
263 | * yielding a 64-bit result. | |
264 | */ | |
265 | static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift) | |
266 | { | |
267 | u64 product; | |
268 | #ifdef __i386__ | |
269 | u32 tmp1, tmp2; | |
270 | #endif | |
271 | ||
272 | if (shift < 0) | |
273 | delta >>= -shift; | |
274 | else | |
275 | delta <<= shift; | |
276 | ||
277 | #ifdef __i386__ | |
278 | __asm__ ( | |
279 | "mul %5 ; " | |
280 | "mov %4,%%eax ; " | |
281 | "mov %%edx,%4 ; " | |
282 | "mul %5 ; " | |
283 | "xor %5,%5 ; " | |
284 | "add %4,%%eax ; " | |
285 | "adc %5,%%edx ; " | |
286 | : "=A" (product), "=r" (tmp1), "=r" (tmp2) | |
287 | : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) ); | |
288 | #elif __x86_64__ | |
289 | __asm__ ( | |
290 | "mul %%rdx ; shrd $32,%%rdx,%%rax" | |
291 | : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) ); | |
292 | #else | |
293 | #error implement me! | |
294 | #endif | |
295 | ||
296 | return product; | |
297 | } | |
298 | ||
299 | static u64 get_nsec_offset(struct shadow_time_info *shadow) | |
300 | { | |
301 | u64 now, delta; | |
f91a8b44 | 302 | now = native_read_tsc(); |
15c84731 JF |
303 | delta = now - shadow->tsc_timestamp; |
304 | return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift); | |
305 | } | |
306 | ||
ab550288 | 307 | static cycle_t xen_clocksource_read(void) |
15c84731 JF |
308 | { |
309 | struct shadow_time_info *shadow = &get_cpu_var(shadow_time); | |
310 | cycle_t ret; | |
f91a8b44 | 311 | unsigned version; |
15c84731 | 312 | |
f91a8b44 JF |
313 | do { |
314 | version = get_time_values_from_xen(); | |
315 | barrier(); | |
316 | ret = shadow->system_timestamp + get_nsec_offset(shadow); | |
317 | barrier(); | |
318 | } while (version != __get_cpu_var(xen_vcpu)->time.version); | |
15c84731 JF |
319 | |
320 | put_cpu_var(shadow_time); | |
321 | ||
322 | return ret; | |
323 | } | |
324 | ||
325 | static void xen_read_wallclock(struct timespec *ts) | |
326 | { | |
327 | const struct shared_info *s = HYPERVISOR_shared_info; | |
328 | u32 version; | |
329 | u64 delta; | |
330 | struct timespec now; | |
331 | ||
332 | /* get wallclock at system boot */ | |
333 | do { | |
334 | version = s->wc_version; | |
335 | rmb(); /* fetch version before time */ | |
336 | now.tv_sec = s->wc_sec; | |
337 | now.tv_nsec = s->wc_nsec; | |
338 | rmb(); /* fetch time before checking version */ | |
339 | } while ((s->wc_version & 1) | (version ^ s->wc_version)); | |
340 | ||
341 | delta = xen_clocksource_read(); /* time since system boot */ | |
342 | delta += now.tv_sec * (u64)NSEC_PER_SEC + now.tv_nsec; | |
343 | ||
344 | now.tv_nsec = do_div(delta, NSEC_PER_SEC); | |
345 | now.tv_sec = delta; | |
346 | ||
347 | set_normalized_timespec(ts, now.tv_sec, now.tv_nsec); | |
348 | } | |
349 | ||
350 | unsigned long xen_get_wallclock(void) | |
351 | { | |
352 | struct timespec ts; | |
353 | ||
354 | xen_read_wallclock(&ts); | |
355 | ||
356 | return ts.tv_sec; | |
357 | } | |
358 | ||
359 | int xen_set_wallclock(unsigned long now) | |
360 | { | |
361 | /* do nothing for domU */ | |
362 | return -1; | |
363 | } | |
364 | ||
365 | static struct clocksource xen_clocksource __read_mostly = { | |
366 | .name = "xen", | |
367 | .rating = 400, | |
368 | .read = xen_clocksource_read, | |
369 | .mask = ~0, | |
370 | .mult = 1<<XEN_SHIFT, /* time directly in nanoseconds */ | |
371 | .shift = XEN_SHIFT, | |
372 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, | |
373 | }; | |
374 | ||
375 | /* | |
376 | Xen clockevent implementation | |
377 | ||
378 | Xen has two clockevent implementations: | |
379 | ||
380 | The old timer_op one works with all released versions of Xen prior | |
381 | to version 3.0.4. This version of the hypervisor provides a | |
382 | single-shot timer with nanosecond resolution. However, sharing the | |
383 | same event channel is a 100Hz tick which is delivered while the | |
384 | vcpu is running. We don't care about or use this tick, but it will | |
385 | cause the core time code to think the timer fired too soon, and | |
386 | will end up resetting it each time. It could be filtered, but | |
387 | doing so has complications when the ktime clocksource is not yet | |
388 | the xen clocksource (ie, at boot time). | |
389 | ||
390 | The new vcpu_op-based timer interface allows the tick timer period | |
391 | to be changed or turned off. The tick timer is not useful as a | |
392 | periodic timer because events are only delivered to running vcpus. | |
393 | The one-shot timer can report when a timeout is in the past, so | |
394 | set_next_event is capable of returning -ETIME when appropriate. | |
395 | This interface is used when available. | |
396 | */ | |
397 | ||
398 | ||
399 | /* | |
400 | Get a hypervisor absolute time. In theory we could maintain an | |
401 | offset between the kernel's time and the hypervisor's time, and | |
402 | apply that to a kernel's absolute timeout. Unfortunately the | |
403 | hypervisor and kernel times can drift even if the kernel is using | |
404 | the Xen clocksource, because ntp can warp the kernel's clocksource. | |
405 | */ | |
406 | static s64 get_abs_timeout(unsigned long delta) | |
407 | { | |
408 | return xen_clocksource_read() + delta; | |
409 | } | |
410 | ||
411 | static void xen_timerop_set_mode(enum clock_event_mode mode, | |
412 | struct clock_event_device *evt) | |
413 | { | |
414 | switch (mode) { | |
415 | case CLOCK_EVT_MODE_PERIODIC: | |
416 | /* unsupported */ | |
417 | WARN_ON(1); | |
418 | break; | |
419 | ||
420 | case CLOCK_EVT_MODE_ONESHOT: | |
18de5bc4 | 421 | case CLOCK_EVT_MODE_RESUME: |
15c84731 JF |
422 | break; |
423 | ||
424 | case CLOCK_EVT_MODE_UNUSED: | |
425 | case CLOCK_EVT_MODE_SHUTDOWN: | |
426 | HYPERVISOR_set_timer_op(0); /* cancel timeout */ | |
427 | break; | |
428 | } | |
429 | } | |
430 | ||
431 | static int xen_timerop_set_next_event(unsigned long delta, | |
432 | struct clock_event_device *evt) | |
433 | { | |
434 | WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT); | |
435 | ||
436 | if (HYPERVISOR_set_timer_op(get_abs_timeout(delta)) < 0) | |
437 | BUG(); | |
438 | ||
439 | /* We may have missed the deadline, but there's no real way of | |
440 | knowing for sure. If the event was in the past, then we'll | |
441 | get an immediate interrupt. */ | |
442 | ||
443 | return 0; | |
444 | } | |
445 | ||
446 | static const struct clock_event_device xen_timerop_clockevent = { | |
447 | .name = "xen", | |
448 | .features = CLOCK_EVT_FEAT_ONESHOT, | |
449 | ||
450 | .max_delta_ns = 0xffffffff, | |
451 | .min_delta_ns = TIMER_SLOP, | |
452 | ||
453 | .mult = 1, | |
454 | .shift = 0, | |
455 | .rating = 500, | |
456 | ||
457 | .set_mode = xen_timerop_set_mode, | |
458 | .set_next_event = xen_timerop_set_next_event, | |
459 | }; | |
460 | ||
461 | ||
462 | ||
463 | static void xen_vcpuop_set_mode(enum clock_event_mode mode, | |
464 | struct clock_event_device *evt) | |
465 | { | |
466 | int cpu = smp_processor_id(); | |
467 | ||
468 | switch (mode) { | |
469 | case CLOCK_EVT_MODE_PERIODIC: | |
470 | WARN_ON(1); /* unsupported */ | |
471 | break; | |
472 | ||
473 | case CLOCK_EVT_MODE_ONESHOT: | |
474 | if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL)) | |
475 | BUG(); | |
476 | break; | |
477 | ||
478 | case CLOCK_EVT_MODE_UNUSED: | |
479 | case CLOCK_EVT_MODE_SHUTDOWN: | |
480 | if (HYPERVISOR_vcpu_op(VCPUOP_stop_singleshot_timer, cpu, NULL) || | |
481 | HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL)) | |
482 | BUG(); | |
483 | break; | |
18de5bc4 TG |
484 | case CLOCK_EVT_MODE_RESUME: |
485 | break; | |
15c84731 JF |
486 | } |
487 | } | |
488 | ||
489 | static int xen_vcpuop_set_next_event(unsigned long delta, | |
490 | struct clock_event_device *evt) | |
491 | { | |
492 | int cpu = smp_processor_id(); | |
493 | struct vcpu_set_singleshot_timer single; | |
494 | int ret; | |
495 | ||
496 | WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT); | |
497 | ||
498 | single.timeout_abs_ns = get_abs_timeout(delta); | |
499 | single.flags = VCPU_SSHOTTMR_future; | |
500 | ||
501 | ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, cpu, &single); | |
502 | ||
503 | BUG_ON(ret != 0 && ret != -ETIME); | |
504 | ||
505 | return ret; | |
506 | } | |
507 | ||
508 | static const struct clock_event_device xen_vcpuop_clockevent = { | |
509 | .name = "xen", | |
510 | .features = CLOCK_EVT_FEAT_ONESHOT, | |
511 | ||
512 | .max_delta_ns = 0xffffffff, | |
513 | .min_delta_ns = TIMER_SLOP, | |
514 | ||
515 | .mult = 1, | |
516 | .shift = 0, | |
517 | .rating = 500, | |
518 | ||
519 | .set_mode = xen_vcpuop_set_mode, | |
520 | .set_next_event = xen_vcpuop_set_next_event, | |
521 | }; | |
522 | ||
523 | static const struct clock_event_device *xen_clockevent = | |
524 | &xen_timerop_clockevent; | |
525 | static DEFINE_PER_CPU(struct clock_event_device, xen_clock_events); | |
526 | ||
527 | static irqreturn_t xen_timer_interrupt(int irq, void *dev_id) | |
528 | { | |
529 | struct clock_event_device *evt = &__get_cpu_var(xen_clock_events); | |
530 | irqreturn_t ret; | |
531 | ||
532 | ret = IRQ_NONE; | |
533 | if (evt->event_handler) { | |
534 | evt->event_handler(evt); | |
535 | ret = IRQ_HANDLED; | |
536 | } | |
537 | ||
f91a8b44 JF |
538 | do_stolen_accounting(); |
539 | ||
15c84731 JF |
540 | return ret; |
541 | } | |
542 | ||
f87e4cac | 543 | void xen_setup_timer(int cpu) |
15c84731 JF |
544 | { |
545 | const char *name; | |
546 | struct clock_event_device *evt; | |
547 | int irq; | |
548 | ||
549 | printk(KERN_INFO "installing Xen timer for CPU %d\n", cpu); | |
550 | ||
551 | name = kasprintf(GFP_KERNEL, "timer%d", cpu); | |
552 | if (!name) | |
553 | name = "<timer kasprintf failed>"; | |
554 | ||
555 | irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt, | |
556 | IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING, | |
557 | name, NULL); | |
558 | ||
f87e4cac | 559 | evt = &per_cpu(xen_clock_events, cpu); |
15c84731 JF |
560 | memcpy(evt, xen_clockevent, sizeof(*evt)); |
561 | ||
562 | evt->cpumask = cpumask_of_cpu(cpu); | |
563 | evt->irq = irq; | |
15c84731 | 564 | |
f91a8b44 | 565 | setup_runstate_info(cpu); |
f87e4cac JF |
566 | } |
567 | ||
568 | void xen_setup_cpu_clockevents(void) | |
569 | { | |
570 | BUG_ON(preemptible()); | |
f91a8b44 | 571 | |
f87e4cac | 572 | clockevents_register_device(&__get_cpu_var(xen_clock_events)); |
15c84731 JF |
573 | } |
574 | ||
575 | __init void xen_time_init(void) | |
576 | { | |
577 | int cpu = smp_processor_id(); | |
578 | ||
579 | get_time_values_from_xen(); | |
580 | ||
581 | clocksource_register(&xen_clocksource); | |
582 | ||
583 | if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL) == 0) { | |
f91a8b44 | 584 | /* Successfully turned off 100Hz tick, so we have the |
15c84731 JF |
585 | vcpuop-based timer interface */ |
586 | printk(KERN_DEBUG "Xen: using vcpuop timer interface\n"); | |
587 | xen_clockevent = &xen_vcpuop_clockevent; | |
588 | } | |
589 | ||
590 | /* Set initial system time with full resolution */ | |
591 | xen_read_wallclock(&xtime); | |
592 | set_normalized_timespec(&wall_to_monotonic, | |
593 | -xtime.tv_sec, -xtime.tv_nsec); | |
594 | ||
404ee5b1 | 595 | setup_force_cpu_cap(X86_FEATURE_TSC); |
15c84731 JF |
596 | |
597 | xen_setup_timer(cpu); | |
f87e4cac | 598 | xen_setup_cpu_clockevents(); |
15c84731 | 599 | } |