Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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> |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 14 | #include <linux/kernel_stat.h> |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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 |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 29 | #define NS_PER_TICK (1000000000LL / HZ) |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 30 | |
Jeremy Fitzhardinge | ab55028 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 31 | static cycle_t xen_clocksource_read(void); |
| 32 | |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | f120f13 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 91 | BUG_ON(preemptible()); |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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); |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 106 | } |
| 107 | |
Jeremy Fitzhardinge | f0d7339 | 2007-10-16 11:51:30 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | ab55028 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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; |
Jeremy Fitzhardinge | f120f13 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 186 | cycle_t now; |
| 187 | u64 ret; |
Jeremy Fitzhardinge | ab55028 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 188 | s64 offset; |
| 189 | |
Jeremy Fitzhardinge | f120f13 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | ab55028 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | f120f13 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 207 | ret = state.time[RUNSTATE_blocked] + |
Jeremy Fitzhardinge | ab55028 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 208 | state.time[RUNSTATE_running] + |
| 209 | offset; |
Jeremy Fitzhardinge | f120f13 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 210 | |
| 211 | preempt_enable(); |
| 212 | |
| 213 | return ret; |
Jeremy Fitzhardinge | ab55028 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 214 | } |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 215 | |
| 216 | |
| 217 | /* Get the CPU speed from Xen */ |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 218 | unsigned long xen_cpu_khz(void) |
| 219 | { |
Harvey Harrison | 88a5ac8 | 2008-02-09 23:24:08 +0100 | [diff] [blame] | 220 | u64 xen_khz = 1000000ULL << 32; |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 221 | const struct vcpu_time_info *info = |
| 222 | &HYPERVISOR_shared_info->vcpu_info[0].time; |
| 223 | |
Harvey Harrison | 88a5ac8 | 2008-02-09 23:24:08 +0100 | [diff] [blame] | 224 | do_div(xen_khz, info->tsc_to_system_mul); |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 225 | if (info->tsc_shift < 0) |
Harvey Harrison | 88a5ac8 | 2008-02-09 23:24:08 +0100 | [diff] [blame] | 226 | xen_khz <<= -info->tsc_shift; |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 227 | else |
Harvey Harrison | 88a5ac8 | 2008-02-09 23:24:08 +0100 | [diff] [blame] | 228 | xen_khz >>= info->tsc_shift; |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 229 | |
Harvey Harrison | 88a5ac8 | 2008-02-09 23:24:08 +0100 | [diff] [blame] | 230 | return xen_khz; |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 231 | } |
| 232 | |
| 233 | /* |
| 234 | * Reads a consistent set of time-base values from Xen, into a shadow data |
| 235 | * area. |
| 236 | */ |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 237 | static unsigned get_time_values_from_xen(void) |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 238 | { |
| 239 | struct vcpu_time_info *src; |
| 240 | struct shadow_time_info *dst; |
| 241 | |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 258 | return dst->version; |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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; |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 302 | now = native_read_tsc(); |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 303 | delta = now - shadow->tsc_timestamp; |
| 304 | return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift); |
| 305 | } |
| 306 | |
Jeremy Fitzhardinge | ab55028 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 307 | static cycle_t xen_clocksource_read(void) |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 308 | { |
| 309 | struct shadow_time_info *shadow = &get_cpu_var(shadow_time); |
| 310 | cycle_t ret; |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 311 | unsigned version; |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 312 | |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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); |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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: |
Thomas Gleixner | 18de5bc | 2007-07-21 04:37:34 -0700 | [diff] [blame] | 421 | case CLOCK_EVT_MODE_RESUME: |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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; |
Thomas Gleixner | 18de5bc | 2007-07-21 04:37:34 -0700 | [diff] [blame] | 484 | case CLOCK_EVT_MODE_RESUME: |
| 485 | break; |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 538 | do_stolen_accounting(); |
| 539 | |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 540 | return ret; |
| 541 | } |
| 542 | |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 543 | void xen_setup_timer(int cpu) |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 559 | evt = &per_cpu(xen_clock_events, cpu); |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 560 | memcpy(evt, xen_clockevent, sizeof(*evt)); |
| 561 | |
| 562 | evt->cpumask = cpumask_of_cpu(cpu); |
| 563 | evt->irq = irq; |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 564 | |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 565 | setup_runstate_info(cpu); |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 566 | } |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 567 | |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 568 | void xen_setup_cpu_clockevents(void) |
| 569 | { |
| 570 | BUG_ON(preemptible()); |
| 571 | |
| 572 | clockevents_register_device(&__get_cpu_var(xen_clock_events)); |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 573 | } |
| 574 | |
Jeremy Fitzhardinge | d07af1f | 2008-05-31 01:33:03 +0100 | [diff] [blame^] | 575 | void xen_timer_resume(void) |
| 576 | { |
| 577 | int cpu; |
| 578 | |
| 579 | if (xen_clockevent != &xen_vcpuop_clockevent) |
| 580 | return; |
| 581 | |
| 582 | for_each_online_cpu(cpu) { |
| 583 | if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL)) |
| 584 | BUG(); |
| 585 | } |
| 586 | } |
| 587 | |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 588 | __init void xen_time_init(void) |
| 589 | { |
| 590 | int cpu = smp_processor_id(); |
| 591 | |
| 592 | get_time_values_from_xen(); |
| 593 | |
| 594 | clocksource_register(&xen_clocksource); |
| 595 | |
| 596 | if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL) == 0) { |
Jeremy Fitzhardinge | f91a8b4 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 597 | /* Successfully turned off 100Hz tick, so we have the |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 598 | vcpuop-based timer interface */ |
| 599 | printk(KERN_DEBUG "Xen: using vcpuop timer interface\n"); |
| 600 | xen_clockevent = &xen_vcpuop_clockevent; |
| 601 | } |
| 602 | |
| 603 | /* Set initial system time with full resolution */ |
| 604 | xen_read_wallclock(&xtime); |
| 605 | set_normalized_timespec(&wall_to_monotonic, |
| 606 | -xtime.tv_sec, -xtime.tv_nsec); |
| 607 | |
Andi Kleen | 404ee5b | 2008-01-30 13:33:20 +0100 | [diff] [blame] | 608 | setup_force_cpu_cap(X86_FEATURE_TSC); |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 609 | |
| 610 | xen_setup_timer(cpu); |
Jeremy Fitzhardinge | f87e4ca | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 611 | xen_setup_cpu_clockevents(); |
Jeremy Fitzhardinge | 15c8473 | 2007-07-17 18:37:05 -0700 | [diff] [blame] | 612 | } |