Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[linux-2.6-microblaze.git] / arch / ia64 / kernel / time.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * linux/arch/ia64/kernel/time.c
4  *
5  * Copyright (C) 1998-2003 Hewlett-Packard Co
6  *      Stephane Eranian <eranian@hpl.hp.com>
7  *      David Mosberger <davidm@hpl.hp.com>
8  * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
9  * Copyright (C) 1999-2000 VA Linux Systems
10  * Copyright (C) 1999-2000 Walt Drummond <drummond@valinux.com>
11  */
12
13 #include <linux/cpu.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/profile.h>
18 #include <linux/sched.h>
19 #include <linux/time.h>
20 #include <linux/nmi.h>
21 #include <linux/interrupt.h>
22 #include <linux/efi.h>
23 #include <linux/timex.h>
24 #include <linux/timekeeper_internal.h>
25 #include <linux/platform_device.h>
26 #include <linux/sched/cputime.h>
27
28 #include <asm/delay.h>
29 #include <asm/hw_irq.h>
30 #include <asm/ptrace.h>
31 #include <asm/sal.h>
32 #include <asm/sections.h>
33
34 #include "fsyscall_gtod_data.h"
35
36 static u64 itc_get_cycles(struct clocksource *cs);
37
38 struct fsyscall_gtod_data_t fsyscall_gtod_data;
39
40 struct itc_jitter_data_t itc_jitter_data;
41
42 volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
43
44 #ifdef CONFIG_IA64_DEBUG_IRQ
45
46 unsigned long last_cli_ip;
47 EXPORT_SYMBOL(last_cli_ip);
48
49 #endif
50
51 static struct clocksource clocksource_itc = {
52         .name           = "itc",
53         .rating         = 350,
54         .read           = itc_get_cycles,
55         .mask           = CLOCKSOURCE_MASK(64),
56         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
57 };
58 static struct clocksource *itc_clocksource;
59
60 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
61
62 #include <linux/kernel_stat.h>
63
64 extern u64 cycle_to_nsec(u64 cyc);
65
66 void vtime_flush(struct task_struct *tsk)
67 {
68         struct thread_info *ti = task_thread_info(tsk);
69         u64 delta;
70
71         if (ti->utime)
72                 account_user_time(tsk, cycle_to_nsec(ti->utime));
73
74         if (ti->gtime)
75                 account_guest_time(tsk, cycle_to_nsec(ti->gtime));
76
77         if (ti->idle_time)
78                 account_idle_time(cycle_to_nsec(ti->idle_time));
79
80         if (ti->stime) {
81                 delta = cycle_to_nsec(ti->stime);
82                 account_system_index_time(tsk, delta, CPUTIME_SYSTEM);
83         }
84
85         if (ti->hardirq_time) {
86                 delta = cycle_to_nsec(ti->hardirq_time);
87                 account_system_index_time(tsk, delta, CPUTIME_IRQ);
88         }
89
90         if (ti->softirq_time) {
91                 delta = cycle_to_nsec(ti->softirq_time);
92                 account_system_index_time(tsk, delta, CPUTIME_SOFTIRQ);
93         }
94
95         ti->utime = 0;
96         ti->gtime = 0;
97         ti->idle_time = 0;
98         ti->stime = 0;
99         ti->hardirq_time = 0;
100         ti->softirq_time = 0;
101 }
102
103 /*
104  * Called from the context switch with interrupts disabled, to charge all
105  * accumulated times to the current process, and to prepare accounting on
106  * the next process.
107  */
108 void arch_vtime_task_switch(struct task_struct *prev)
109 {
110         struct thread_info *pi = task_thread_info(prev);
111         struct thread_info *ni = task_thread_info(current);
112
113         ni->ac_stamp = pi->ac_stamp;
114         ni->ac_stime = ni->ac_utime = 0;
115 }
116
117 /*
118  * Account time for a transition between system, hard irq or soft irq state.
119  * Note that this function is called with interrupts enabled.
120  */
121 static __u64 vtime_delta(struct task_struct *tsk)
122 {
123         struct thread_info *ti = task_thread_info(tsk);
124         __u64 now, delta_stime;
125
126         WARN_ON_ONCE(!irqs_disabled());
127
128         now = ia64_get_itc();
129         delta_stime = now - ti->ac_stamp;
130         ti->ac_stamp = now;
131
132         return delta_stime;
133 }
134
135 void vtime_account_kernel(struct task_struct *tsk)
136 {
137         struct thread_info *ti = task_thread_info(tsk);
138         __u64 stime = vtime_delta(tsk);
139
140         if ((tsk->flags & PF_VCPU) && !irq_count())
141                 ti->gtime += stime;
142         else if (hardirq_count())
143                 ti->hardirq_time += stime;
144         else if (in_serving_softirq())
145                 ti->softirq_time += stime;
146         else
147                 ti->stime += stime;
148 }
149 EXPORT_SYMBOL_GPL(vtime_account_kernel);
150
151 void vtime_account_idle(struct task_struct *tsk)
152 {
153         struct thread_info *ti = task_thread_info(tsk);
154
155         ti->idle_time += vtime_delta(tsk);
156 }
157
158 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
159
160 static irqreturn_t
161 timer_interrupt (int irq, void *dev_id)
162 {
163         unsigned long new_itm;
164
165         if (cpu_is_offline(smp_processor_id())) {
166                 return IRQ_HANDLED;
167         }
168
169         new_itm = local_cpu_data->itm_next;
170
171         if (!time_after(ia64_get_itc(), new_itm))
172                 printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n",
173                        ia64_get_itc(), new_itm);
174
175         profile_tick(CPU_PROFILING);
176
177         while (1) {
178                 update_process_times(user_mode(get_irq_regs()));
179
180                 new_itm += local_cpu_data->itm_delta;
181
182                 if (smp_processor_id() == time_keeper_id)
183                         xtime_update(1);
184
185                 local_cpu_data->itm_next = new_itm;
186
187                 if (time_after(new_itm, ia64_get_itc()))
188                         break;
189
190                 /*
191                  * Allow IPIs to interrupt the timer loop.
192                  */
193                 local_irq_enable();
194                 local_irq_disable();
195         }
196
197         do {
198                 /*
199                  * If we're too close to the next clock tick for
200                  * comfort, we increase the safety margin by
201                  * intentionally dropping the next tick(s).  We do NOT
202                  * update itm.next because that would force us to call
203                  * xtime_update() which in turn would let our clock run
204                  * too fast (with the potentially devastating effect
205                  * of losing monotony of time).
206                  */
207                 while (!time_after(new_itm, ia64_get_itc() + local_cpu_data->itm_delta/2))
208                         new_itm += local_cpu_data->itm_delta;
209                 ia64_set_itm(new_itm);
210                 /* double check, in case we got hit by a (slow) PMI: */
211         } while (time_after_eq(ia64_get_itc(), new_itm));
212         return IRQ_HANDLED;
213 }
214
215 /*
216  * Encapsulate access to the itm structure for SMP.
217  */
218 void
219 ia64_cpu_local_tick (void)
220 {
221         int cpu = smp_processor_id();
222         unsigned long shift = 0, delta;
223
224         /* arrange for the cycle counter to generate a timer interrupt: */
225         ia64_set_itv(IA64_TIMER_VECTOR);
226
227         delta = local_cpu_data->itm_delta;
228         /*
229          * Stagger the timer tick for each CPU so they don't occur all at (almost) the
230          * same time:
231          */
232         if (cpu) {
233                 unsigned long hi = 1UL << ia64_fls(cpu);
234                 shift = (2*(cpu - hi) + 1) * delta/hi/2;
235         }
236         local_cpu_data->itm_next = ia64_get_itc() + delta + shift;
237         ia64_set_itm(local_cpu_data->itm_next);
238 }
239
240 static int nojitter;
241
242 static int __init nojitter_setup(char *str)
243 {
244         nojitter = 1;
245         printk("Jitter checking for ITC timers disabled\n");
246         return 1;
247 }
248
249 __setup("nojitter", nojitter_setup);
250
251
252 void ia64_init_itm(void)
253 {
254         unsigned long platform_base_freq, itc_freq;
255         struct pal_freq_ratio itc_ratio, proc_ratio;
256         long status, platform_base_drift, itc_drift;
257
258         /*
259          * According to SAL v2.6, we need to use a SAL call to determine the platform base
260          * frequency and then a PAL call to determine the frequency ratio between the ITC
261          * and the base frequency.
262          */
263         status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM,
264                                     &platform_base_freq, &platform_base_drift);
265         if (status != 0) {
266                 printk(KERN_ERR "SAL_FREQ_BASE_PLATFORM failed: %s\n", ia64_sal_strerror(status));
267         } else {
268                 status = ia64_pal_freq_ratios(&proc_ratio, NULL, &itc_ratio);
269                 if (status != 0)
270                         printk(KERN_ERR "PAL_FREQ_RATIOS failed with status=%ld\n", status);
271         }
272         if (status != 0) {
273                 /* invent "random" values */
274                 printk(KERN_ERR
275                        "SAL/PAL failed to obtain frequency info---inventing reasonable values\n");
276                 platform_base_freq = 100000000;
277                 platform_base_drift = -1;       /* no drift info */
278                 itc_ratio.num = 3;
279                 itc_ratio.den = 1;
280         }
281         if (platform_base_freq < 40000000) {
282                 printk(KERN_ERR "Platform base frequency %lu bogus---resetting to 75MHz!\n",
283                        platform_base_freq);
284                 platform_base_freq = 75000000;
285                 platform_base_drift = -1;
286         }
287         if (!proc_ratio.den)
288                 proc_ratio.den = 1;     /* avoid division by zero */
289         if (!itc_ratio.den)
290                 itc_ratio.den = 1;      /* avoid division by zero */
291
292         itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den;
293
294         local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ;
295         printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, "
296                "ITC freq=%lu.%03luMHz", smp_processor_id(),
297                platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000,
298                itc_ratio.num, itc_ratio.den, itc_freq / 1000000, (itc_freq / 1000) % 1000);
299
300         if (platform_base_drift != -1) {
301                 itc_drift = platform_base_drift*itc_ratio.num/itc_ratio.den;
302                 printk("+/-%ldppm\n", itc_drift);
303         } else {
304                 itc_drift = -1;
305                 printk("\n");
306         }
307
308         local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den;
309         local_cpu_data->itc_freq = itc_freq;
310         local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC;
311         local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT)
312                                         + itc_freq/2)/itc_freq;
313
314         if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
315 #ifdef CONFIG_SMP
316                 /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
317                  * Jitter compensation requires a cmpxchg which may limit
318                  * the scalability of the syscalls for retrieving time.
319                  * The ITC synchronization is usually successful to within a few
320                  * ITC ticks but this is not a sure thing. If you need to improve
321                  * timer performance in SMP situations then boot the kernel with the
322                  * "nojitter" option. However, doing so may result in time fluctuating (maybe
323                  * even going backward) if the ITC offsets between the individual CPUs
324                  * are too large.
325                  */
326                 if (!nojitter)
327                         itc_jitter_data.itc_jitter = 1;
328 #endif
329         } else
330                 /*
331                  * ITC is drifty and we have not synchronized the ITCs in smpboot.c.
332                  * ITC values may fluctuate significantly between processors.
333                  * Clock should not be used for hrtimers. Mark itc as only
334                  * useful for boot and testing.
335                  *
336                  * Note that jitter compensation is off! There is no point of
337                  * synchronizing ITCs since they may be large differentials
338                  * that change over time.
339                  *
340                  * The only way to fix this would be to repeatedly sync the
341                  * ITCs. Until that time we have to avoid ITC.
342                  */
343                 clocksource_itc.rating = 50;
344
345         /* avoid softlock up message when cpu is unplug and plugged again. */
346         touch_softlockup_watchdog();
347
348         /* Setup the CPU local timer tick */
349         ia64_cpu_local_tick();
350
351         if (!itc_clocksource) {
352                 clocksource_register_hz(&clocksource_itc,
353                                                 local_cpu_data->itc_freq);
354                 itc_clocksource = &clocksource_itc;
355         }
356 }
357
358 static u64 itc_get_cycles(struct clocksource *cs)
359 {
360         unsigned long lcycle, now, ret;
361
362         if (!itc_jitter_data.itc_jitter)
363                 return get_cycles();
364
365         lcycle = itc_jitter_data.itc_lastcycle;
366         now = get_cycles();
367         if (lcycle && time_after(lcycle, now))
368                 return lcycle;
369
370         /*
371          * Keep track of the last timer value returned.
372          * In an SMP environment, you could lose out in contention of
373          * cmpxchg. If so, your cmpxchg returns new value which the
374          * winner of contention updated to. Use the new value instead.
375          */
376         ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now);
377         if (unlikely(ret != lcycle))
378                 return ret;
379
380         return now;
381 }
382
383
384 static struct irqaction timer_irqaction = {
385         .handler =      timer_interrupt,
386         .flags =        IRQF_IRQPOLL,
387         .name =         "timer"
388 };
389
390 void read_persistent_clock64(struct timespec64 *ts)
391 {
392         efi_gettimeofday(ts);
393 }
394
395 void __init
396 time_init (void)
397 {
398         register_percpu_irq(IA64_TIMER_VECTOR, &timer_irqaction);
399         ia64_init_itm();
400 }
401
402 /*
403  * Generic udelay assumes that if preemption is allowed and the thread
404  * migrates to another CPU, that the ITC values are synchronized across
405  * all CPUs.
406  */
407 static void
408 ia64_itc_udelay (unsigned long usecs)
409 {
410         unsigned long start = ia64_get_itc();
411         unsigned long end = start + usecs*local_cpu_data->cyc_per_usec;
412
413         while (time_before(ia64_get_itc(), end))
414                 cpu_relax();
415 }
416
417 void (*ia64_udelay)(unsigned long usecs) = &ia64_itc_udelay;
418
419 void
420 udelay (unsigned long usecs)
421 {
422         (*ia64_udelay)(usecs);
423 }
424 EXPORT_SYMBOL(udelay);
425
426 /* IA64 doesn't cache the timezone */
427 void update_vsyscall_tz(void)
428 {
429 }
430
431 void update_vsyscall(struct timekeeper *tk)
432 {
433         write_seqcount_begin(&fsyscall_gtod_data.seq);
434
435         /* copy vsyscall data */
436         fsyscall_gtod_data.clk_mask = tk->tkr_mono.mask;
437         fsyscall_gtod_data.clk_mult = tk->tkr_mono.mult;
438         fsyscall_gtod_data.clk_shift = tk->tkr_mono.shift;
439         fsyscall_gtod_data.clk_fsys_mmio = tk->tkr_mono.clock->archdata.fsys_mmio;
440         fsyscall_gtod_data.clk_cycle_last = tk->tkr_mono.cycle_last;
441
442         fsyscall_gtod_data.wall_time.sec = tk->xtime_sec;
443         fsyscall_gtod_data.wall_time.snsec = tk->tkr_mono.xtime_nsec;
444
445         fsyscall_gtod_data.monotonic_time.sec = tk->xtime_sec
446                                               + tk->wall_to_monotonic.tv_sec;
447         fsyscall_gtod_data.monotonic_time.snsec = tk->tkr_mono.xtime_nsec
448                                                 + ((u64)tk->wall_to_monotonic.tv_nsec
449                                                         << tk->tkr_mono.shift);
450
451         /* normalize */
452         while (fsyscall_gtod_data.monotonic_time.snsec >=
453                                         (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
454                 fsyscall_gtod_data.monotonic_time.snsec -=
455                                         ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift;
456                 fsyscall_gtod_data.monotonic_time.sec++;
457         }
458
459         write_seqcount_end(&fsyscall_gtod_data.seq);
460 }
461