time: Convert CONFIG_GENERIC_TIME_VSYSCALL to CONFIG_GENERIC_TIME_VSYSCALL_OLD
[linux-3.10.git] / arch / ia64 / kernel / time.c
1 /*
2  * linux/arch/ia64/kernel/time.c
3  *
4  * Copyright (C) 1998-2003 Hewlett-Packard Co
5  *      Stephane Eranian <eranian@hpl.hp.com>
6  *      David Mosberger <davidm@hpl.hp.com>
7  * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
8  * Copyright (C) 1999-2000 VA Linux Systems
9  * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com>
10  */
11
12 #include <linux/cpu.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/profile.h>
17 #include <linux/sched.h>
18 #include <linux/time.h>
19 #include <linux/interrupt.h>
20 #include <linux/efi.h>
21 #include <linux/timex.h>
22 #include <linux/timekeeper_internal.h>
23 #include <linux/platform_device.h>
24
25 #include <asm/machvec.h>
26 #include <asm/delay.h>
27 #include <asm/hw_irq.h>
28 #include <asm/paravirt.h>
29 #include <asm/ptrace.h>
30 #include <asm/sal.h>
31 #include <asm/sections.h>
32
33 #include "fsyscall_gtod_data.h"
34
35 static cycle_t itc_get_cycles(struct clocksource *cs);
36
37 struct fsyscall_gtod_data_t fsyscall_gtod_data;
38
39 struct itc_jitter_data_t itc_jitter_data;
40
41 volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
42
43 #ifdef CONFIG_IA64_DEBUG_IRQ
44
45 unsigned long last_cli_ip;
46 EXPORT_SYMBOL(last_cli_ip);
47
48 #endif
49
50 #ifdef CONFIG_PARAVIRT
51 /* We need to define a real function for sched_clock, to override the
52    weak default version */
53 unsigned long long sched_clock(void)
54 {
55         return paravirt_sched_clock();
56 }
57 #endif
58
59 #ifdef CONFIG_PARAVIRT
60 static void
61 paravirt_clocksource_resume(struct clocksource *cs)
62 {
63         if (pv_time_ops.clocksource_resume)
64                 pv_time_ops.clocksource_resume();
65 }
66 #endif
67
68 static struct clocksource clocksource_itc = {
69         .name           = "itc",
70         .rating         = 350,
71         .read           = itc_get_cycles,
72         .mask           = CLOCKSOURCE_MASK(64),
73         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
74 #ifdef CONFIG_PARAVIRT
75         .resume         = paravirt_clocksource_resume,
76 #endif
77 };
78 static struct clocksource *itc_clocksource;
79
80 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
81
82 #include <linux/kernel_stat.h>
83
84 extern cputime_t cycle_to_cputime(u64 cyc);
85
86 /*
87  * Called from the context switch with interrupts disabled, to charge all
88  * accumulated times to the current process, and to prepare accounting on
89  * the next process.
90  */
91 void ia64_account_on_switch(struct task_struct *prev, struct task_struct *next)
92 {
93         struct thread_info *pi = task_thread_info(prev);
94         struct thread_info *ni = task_thread_info(next);
95         cputime_t delta_stime, delta_utime;
96         __u64 now;
97
98         now = ia64_get_itc();
99
100         delta_stime = cycle_to_cputime(pi->ac_stime + (now - pi->ac_stamp));
101         if (idle_task(smp_processor_id()) != prev)
102                 account_system_time(prev, 0, delta_stime, delta_stime);
103         else
104                 account_idle_time(delta_stime);
105
106         if (pi->ac_utime) {
107                 delta_utime = cycle_to_cputime(pi->ac_utime);
108                 account_user_time(prev, delta_utime, delta_utime);
109         }
110
111         pi->ac_stamp = ni->ac_stamp = now;
112         ni->ac_stime = ni->ac_utime = 0;
113 }
114
115 /*
116  * Account time for a transition between system, hard irq or soft irq state.
117  * Note that this function is called with interrupts enabled.
118  */
119 void account_system_vtime(struct task_struct *tsk)
120 {
121         struct thread_info *ti = task_thread_info(tsk);
122         unsigned long flags;
123         cputime_t delta_stime;
124         __u64 now;
125
126         local_irq_save(flags);
127
128         now = ia64_get_itc();
129
130         delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp));
131         if (irq_count() || idle_task(smp_processor_id()) != tsk)
132                 account_system_time(tsk, 0, delta_stime, delta_stime);
133         else
134                 account_idle_time(delta_stime);
135         ti->ac_stime = 0;
136
137         ti->ac_stamp = now;
138
139         local_irq_restore(flags);
140 }
141 EXPORT_SYMBOL_GPL(account_system_vtime);
142
143 /*
144  * Called from the timer interrupt handler to charge accumulated user time
145  * to the current process.  Must be called with interrupts disabled.
146  */
147 void account_process_tick(struct task_struct *p, int user_tick)
148 {
149         struct thread_info *ti = task_thread_info(p);
150         cputime_t delta_utime;
151
152         if (ti->ac_utime) {
153                 delta_utime = cycle_to_cputime(ti->ac_utime);
154                 account_user_time(p, delta_utime, delta_utime);
155                 ti->ac_utime = 0;
156         }
157 }
158
159 #endif /* CONFIG_VIRT_CPU_ACCOUNTING */
160
161 static irqreturn_t
162 timer_interrupt (int irq, void *dev_id)
163 {
164         unsigned long new_itm;
165
166         if (cpu_is_offline(smp_processor_id())) {
167                 return IRQ_HANDLED;
168         }
169
170         platform_timer_interrupt(irq, dev_id);
171
172         new_itm = local_cpu_data->itm_next;
173
174         if (!time_after(ia64_get_itc(), new_itm))
175                 printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n",
176                        ia64_get_itc(), new_itm);
177
178         profile_tick(CPU_PROFILING);
179
180         if (paravirt_do_steal_accounting(&new_itm))
181                 goto skip_process_time_accounting;
182
183         while (1) {
184                 update_process_times(user_mode(get_irq_regs()));
185
186                 new_itm += local_cpu_data->itm_delta;
187
188                 if (smp_processor_id() == time_keeper_id)
189                         xtime_update(1);
190
191                 local_cpu_data->itm_next = new_itm;
192
193                 if (time_after(new_itm, ia64_get_itc()))
194                         break;
195
196                 /*
197                  * Allow IPIs to interrupt the timer loop.
198                  */
199                 local_irq_enable();
200                 local_irq_disable();
201         }
202
203 skip_process_time_accounting:
204
205         do {
206                 /*
207                  * If we're too close to the next clock tick for
208                  * comfort, we increase the safety margin by
209                  * intentionally dropping the next tick(s).  We do NOT
210                  * update itm.next because that would force us to call
211                  * xtime_update() which in turn would let our clock run
212                  * too fast (with the potentially devastating effect
213                  * of losing monotony of time).
214                  */
215                 while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
216                         new_itm += local_cpu_data->itm_delta;
217                 ia64_set_itm(new_itm);
218                 /* double check, in case we got hit by a (slow) PMI: */
219         } while (time_after_eq(ia64_get_itc(), new_itm));
220         return IRQ_HANDLED;
221 }
222
223 /*
224  * Encapsulate access to the itm structure for SMP.
225  */
226 void
227 ia64_cpu_local_tick (void)
228 {
229         int cpu = smp_processor_id();
230         unsigned long shift = 0, delta;
231
232         /* arrange for the cycle counter to generate a timer interrupt: */
233         ia64_set_itv(IA64_TIMER_VECTOR);
234
235         delta = local_cpu_data->itm_delta;
236         /*
237          * Stagger the timer tick for each CPU so they don't occur all at (almost) the
238          * same time:
239          */
240         if (cpu) {
241                 unsigned long hi = 1UL << ia64_fls(cpu);
242                 shift = (2*(cpu - hi) + 1) * delta/hi/2;
243         }
244         local_cpu_data->itm_next = ia64_get_itc() + delta + shift;
245         ia64_set_itm(local_cpu_data->itm_next);
246 }
247
248 static int nojitter;
249
250 static int __init nojitter_setup(char *str)
251 {
252         nojitter = 1;
253         printk("Jitter checking for ITC timers disabled\n");
254         return 1;
255 }
256
257 __setup("nojitter", nojitter_setup);
258
259
260 void __devinit
261 ia64_init_itm (void)
262 {
263         unsigned long platform_base_freq, itc_freq;
264         struct pal_freq_ratio itc_ratio, proc_ratio;
265         long status, platform_base_drift, itc_drift;
266
267         /*
268          * According to SAL v2.6, we need to use a SAL call to determine the platform base
269          * frequency and then a PAL call to determine the frequency ratio between the ITC
270          * and the base frequency.
271          */
272         status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM,
273                                     &platform_base_freq, &platform_base_drift);
274         if (status != 0) {
275                 printk(KERN_ERR "SAL_FREQ_BASE_PLATFORM failed: %s\n", ia64_sal_strerror(status));
276         } else {
277                 status = ia64_pal_freq_ratios(&proc_ratio, NULL, &itc_ratio);
278                 if (status != 0)
279                         printk(KERN_ERR "PAL_FREQ_RATIOS failed with status=%ld\n", status);
280         }
281         if (status != 0) {
282                 /* invent "random" values */
283                 printk(KERN_ERR
284                        "SAL/PAL failed to obtain frequency info---inventing reasonable values\n");
285                 platform_base_freq = 100000000;
286                 platform_base_drift = -1;       /* no drift info */
287                 itc_ratio.num = 3;
288                 itc_ratio.den = 1;
289         }
290         if (platform_base_freq < 40000000) {
291                 printk(KERN_ERR "Platform base frequency %lu bogus---resetting to 75MHz!\n",
292                        platform_base_freq);
293                 platform_base_freq = 75000000;
294                 platform_base_drift = -1;
295         }
296         if (!proc_ratio.den)
297                 proc_ratio.den = 1;     /* avoid division by zero */
298         if (!itc_ratio.den)
299                 itc_ratio.den = 1;      /* avoid division by zero */
300
301         itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den;
302
303         local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ;
304         printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, "
305                "ITC freq=%lu.%03luMHz", smp_processor_id(),
306                platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000,
307                itc_ratio.num, itc_ratio.den, itc_freq / 1000000, (itc_freq / 1000) % 1000);
308
309         if (platform_base_drift != -1) {
310                 itc_drift = platform_base_drift*itc_ratio.num/itc_ratio.den;
311                 printk("+/-%ldppm\n", itc_drift);
312         } else {
313                 itc_drift = -1;
314                 printk("\n");
315         }
316
317         local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den;
318         local_cpu_data->itc_freq = itc_freq;
319         local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC;
320         local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT)
321                                         + itc_freq/2)/itc_freq;
322
323         if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
324 #ifdef CONFIG_SMP
325                 /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
326                  * Jitter compensation requires a cmpxchg which may limit
327                  * the scalability of the syscalls for retrieving time.
328                  * The ITC synchronization is usually successful to within a few
329                  * ITC ticks but this is not a sure thing. If you need to improve
330                  * timer performance in SMP situations then boot the kernel with the
331                  * "nojitter" option. However, doing so may result in time fluctuating (maybe
332                  * even going backward) if the ITC offsets between the individual CPUs
333                  * are too large.
334                  */
335                 if (!nojitter)
336                         itc_jitter_data.itc_jitter = 1;
337 #endif
338         } else
339                 /*
340                  * ITC is drifty and we have not synchronized the ITCs in smpboot.c.
341                  * ITC values may fluctuate significantly between processors.
342                  * Clock should not be used for hrtimers. Mark itc as only
343                  * useful for boot and testing.
344                  *
345                  * Note that jitter compensation is off! There is no point of
346                  * synchronizing ITCs since they may be large differentials
347                  * that change over time.
348                  *
349                  * The only way to fix this would be to repeatedly sync the
350                  * ITCs. Until that time we have to avoid ITC.
351                  */
352                 clocksource_itc.rating = 50;
353
354         paravirt_init_missing_ticks_accounting(smp_processor_id());
355
356         /* avoid softlock up message when cpu is unplug and plugged again. */
357         touch_softlockup_watchdog();
358
359         /* Setup the CPU local timer tick */
360         ia64_cpu_local_tick();
361
362         if (!itc_clocksource) {
363                 clocksource_register_hz(&clocksource_itc,
364                                                 local_cpu_data->itc_freq);
365                 itc_clocksource = &clocksource_itc;
366         }
367 }
368
369 static cycle_t itc_get_cycles(struct clocksource *cs)
370 {
371         unsigned long lcycle, now, ret;
372
373         if (!itc_jitter_data.itc_jitter)
374                 return get_cycles();
375
376         lcycle = itc_jitter_data.itc_lastcycle;
377         now = get_cycles();
378         if (lcycle && time_after(lcycle, now))
379                 return lcycle;
380
381         /*
382          * Keep track of the last timer value returned.
383          * In an SMP environment, you could lose out in contention of
384          * cmpxchg. If so, your cmpxchg returns new value which the
385          * winner of contention updated to. Use the new value instead.
386          */
387         ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now);
388         if (unlikely(ret != lcycle))
389                 return ret;
390
391         return now;
392 }
393
394
395 static struct irqaction timer_irqaction = {
396         .handler =      timer_interrupt,
397         .flags =        IRQF_DISABLED | IRQF_IRQPOLL,
398         .name =         "timer"
399 };
400
401 static struct platform_device rtc_efi_dev = {
402         .name = "rtc-efi",
403         .id = -1,
404 };
405
406 static int __init rtc_init(void)
407 {
408         if (platform_device_register(&rtc_efi_dev) < 0)
409                 printk(KERN_ERR "unable to register rtc device...\n");
410
411         /* not necessarily an error */
412         return 0;
413 }
414 module_init(rtc_init);
415
416 void read_persistent_clock(struct timespec *ts)
417 {
418         efi_gettimeofday(ts);
419 }
420
421 void __init
422 time_init (void)
423 {
424         register_percpu_irq(IA64_TIMER_VECTOR, &timer_irqaction);
425         ia64_init_itm();
426 }
427
428 /*
429  * Generic udelay assumes that if preemption is allowed and the thread
430  * migrates to another CPU, that the ITC values are synchronized across
431  * all CPUs.
432  */
433 static void
434 ia64_itc_udelay (unsigned long usecs)
435 {
436         unsigned long start = ia64_get_itc();
437         unsigned long end = start + usecs*local_cpu_data->cyc_per_usec;
438
439         while (time_before(ia64_get_itc(), end))
440                 cpu_relax();
441 }
442
443 void (*ia64_udelay)(unsigned long usecs) = &ia64_itc_udelay;
444
445 void
446 udelay (unsigned long usecs)
447 {
448         (*ia64_udelay)(usecs);
449 }
450 EXPORT_SYMBOL(udelay);
451
452 /* IA64 doesn't cache the timezone */
453 void update_vsyscall_tz(void)
454 {
455 }
456
457 void update_vsyscall_old(struct timespec *wall, struct timespec *wtm,
458                         struct clocksource *c, u32 mult)
459 {
460         write_seqcount_begin(&fsyscall_gtod_data.seq);
461
462         /* copy fsyscall clock data */
463         fsyscall_gtod_data.clk_mask = c->mask;
464         fsyscall_gtod_data.clk_mult = mult;
465         fsyscall_gtod_data.clk_shift = c->shift;
466         fsyscall_gtod_data.clk_fsys_mmio = c->archdata.fsys_mmio;
467         fsyscall_gtod_data.clk_cycle_last = c->cycle_last;
468
469         /* copy kernel time structures */
470         fsyscall_gtod_data.wall_time.tv_sec = wall->tv_sec;
471         fsyscall_gtod_data.wall_time.tv_nsec = wall->tv_nsec;
472         fsyscall_gtod_data.monotonic_time.tv_sec = wtm->tv_sec
473                                                         + wall->tv_sec;
474         fsyscall_gtod_data.monotonic_time.tv_nsec = wtm->tv_nsec
475                                                         + wall->tv_nsec;
476
477         /* normalize */
478         while (fsyscall_gtod_data.monotonic_time.tv_nsec >= NSEC_PER_SEC) {
479                 fsyscall_gtod_data.monotonic_time.tv_nsec -= NSEC_PER_SEC;
480                 fsyscall_gtod_data.monotonic_time.tv_sec++;
481         }
482
483         write_seqcount_end(&fsyscall_gtod_data.seq);
484 }
485