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/cputime.h> 29 #include <asm/delay.h> 30 #include <asm/efi.h> 31 #include <asm/hw_irq.h> 32 #include <asm/ptrace.h> 33 #include <asm/sal.h> 34 #include <asm/sections.h> 35 36 #include "fsyscall_gtod_data.h" 37 #include "irq.h" 38 39 static u64 itc_get_cycles(struct clocksource *cs); 40 41 struct fsyscall_gtod_data_t fsyscall_gtod_data; 42 43 struct itc_jitter_data_t itc_jitter_data; 44 45 volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */ 46 47 #ifdef CONFIG_IA64_DEBUG_IRQ 48 49 unsigned long last_cli_ip; 50 EXPORT_SYMBOL(last_cli_ip); 51 52 #endif 53 54 static struct clocksource clocksource_itc = { 55 .name = "itc", 56 .rating = 350, 57 .read = itc_get_cycles, 58 .mask = CLOCKSOURCE_MASK(64), 59 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 60 }; 61 static struct clocksource *itc_clocksource; 62 63 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 64 65 #include <linux/kernel_stat.h> 66 67 extern u64 cycle_to_nsec(u64 cyc); 68 69 void vtime_flush(struct task_struct *tsk) 70 { 71 struct thread_info *ti = task_thread_info(tsk); 72 u64 delta; 73 74 if (ti->utime) 75 account_user_time(tsk, cycle_to_nsec(ti->utime)); 76 77 if (ti->gtime) 78 account_guest_time(tsk, cycle_to_nsec(ti->gtime)); 79 80 if (ti->idle_time) 81 account_idle_time(cycle_to_nsec(ti->idle_time)); 82 83 if (ti->stime) { 84 delta = cycle_to_nsec(ti->stime); 85 account_system_index_time(tsk, delta, CPUTIME_SYSTEM); 86 } 87 88 if (ti->hardirq_time) { 89 delta = cycle_to_nsec(ti->hardirq_time); 90 account_system_index_time(tsk, delta, CPUTIME_IRQ); 91 } 92 93 if (ti->softirq_time) { 94 delta = cycle_to_nsec(ti->softirq_time); 95 account_system_index_time(tsk, delta, CPUTIME_SOFTIRQ); 96 } 97 98 ti->utime = 0; 99 ti->gtime = 0; 100 ti->idle_time = 0; 101 ti->stime = 0; 102 ti->hardirq_time = 0; 103 ti->softirq_time = 0; 104 } 105 106 /* 107 * Called from the context switch with interrupts disabled, to charge all 108 * accumulated times to the current process, and to prepare accounting on 109 * the next process. 110 */ 111 void arch_vtime_task_switch(struct task_struct *prev) 112 { 113 struct thread_info *pi = task_thread_info(prev); 114 struct thread_info *ni = task_thread_info(current); 115 116 ni->ac_stamp = pi->ac_stamp; 117 ni->ac_stime = ni->ac_utime = 0; 118 } 119 120 /* 121 * Account time for a transition between system, hard irq or soft irq state. 122 * Note that this function is called with interrupts enabled. 123 */ 124 static __u64 vtime_delta(struct task_struct *tsk) 125 { 126 struct thread_info *ti = task_thread_info(tsk); 127 __u64 now, delta_stime; 128 129 WARN_ON_ONCE(!irqs_disabled()); 130 131 now = ia64_get_itc(); 132 delta_stime = now - ti->ac_stamp; 133 ti->ac_stamp = now; 134 135 return delta_stime; 136 } 137 138 void vtime_account_kernel(struct task_struct *tsk) 139 { 140 struct thread_info *ti = task_thread_info(tsk); 141 __u64 stime = vtime_delta(tsk); 142 143 if (tsk->flags & PF_VCPU) 144 ti->gtime += stime; 145 else 146 ti->stime += stime; 147 } 148 EXPORT_SYMBOL_GPL(vtime_account_kernel); 149 150 void vtime_account_idle(struct task_struct *tsk) 151 { 152 struct thread_info *ti = task_thread_info(tsk); 153 154 ti->idle_time += vtime_delta(tsk); 155 } 156 157 void vtime_account_softirq(struct task_struct *tsk) 158 { 159 struct thread_info *ti = task_thread_info(tsk); 160 161 ti->softirq_time += vtime_delta(tsk); 162 } 163 164 void vtime_account_hardirq(struct task_struct *tsk) 165 { 166 struct thread_info *ti = task_thread_info(tsk); 167 168 ti->hardirq_time += vtime_delta(tsk); 169 } 170 171 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 172 173 static irqreturn_t 174 timer_interrupt (int irq, void *dev_id) 175 { 176 unsigned long new_itm; 177 178 if (cpu_is_offline(smp_processor_id())) { 179 return IRQ_HANDLED; 180 } 181 182 new_itm = local_cpu_data->itm_next; 183 184 if (!time_after(ia64_get_itc(), new_itm)) 185 printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n", 186 ia64_get_itc(), new_itm); 187 188 while (1) { 189 new_itm += local_cpu_data->itm_delta; 190 191 legacy_timer_tick(smp_processor_id() == time_keeper_id); 192 193 local_cpu_data->itm_next = new_itm; 194 195 if (time_after(new_itm, ia64_get_itc())) 196 break; 197 198 /* 199 * Allow IPIs to interrupt the timer loop. 200 */ 201 local_irq_enable(); 202 local_irq_disable(); 203 } 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 ia64_init_itm(void) 261 { 262 unsigned long platform_base_freq, itc_freq; 263 struct pal_freq_ratio itc_ratio, proc_ratio; 264 long status, platform_base_drift, itc_drift; 265 266 /* 267 * According to SAL v2.6, we need to use a SAL call to determine the platform base 268 * frequency and then a PAL call to determine the frequency ratio between the ITC 269 * and the base frequency. 270 */ 271 status = ia64_sal_freq_base(SAL_FREQ_BASE_PLATFORM, 272 &platform_base_freq, &platform_base_drift); 273 if (status != 0) { 274 printk(KERN_ERR "SAL_FREQ_BASE_PLATFORM failed: %s\n", ia64_sal_strerror(status)); 275 } else { 276 status = ia64_pal_freq_ratios(&proc_ratio, NULL, &itc_ratio); 277 if (status != 0) 278 printk(KERN_ERR "PAL_FREQ_RATIOS failed with status=%ld\n", status); 279 } 280 if (status != 0) { 281 /* invent "random" values */ 282 printk(KERN_ERR 283 "SAL/PAL failed to obtain frequency info---inventing reasonable values\n"); 284 platform_base_freq = 100000000; 285 platform_base_drift = -1; /* no drift info */ 286 itc_ratio.num = 3; 287 itc_ratio.den = 1; 288 } 289 if (platform_base_freq < 40000000) { 290 printk(KERN_ERR "Platform base frequency %lu bogus---resetting to 75MHz!\n", 291 platform_base_freq); 292 platform_base_freq = 75000000; 293 platform_base_drift = -1; 294 } 295 if (!proc_ratio.den) 296 proc_ratio.den = 1; /* avoid division by zero */ 297 if (!itc_ratio.den) 298 itc_ratio.den = 1; /* avoid division by zero */ 299 300 itc_freq = (platform_base_freq*itc_ratio.num)/itc_ratio.den; 301 302 local_cpu_data->itm_delta = (itc_freq + HZ/2) / HZ; 303 printk(KERN_DEBUG "CPU %d: base freq=%lu.%03luMHz, ITC ratio=%u/%u, " 304 "ITC freq=%lu.%03luMHz", smp_processor_id(), 305 platform_base_freq / 1000000, (platform_base_freq / 1000) % 1000, 306 itc_ratio.num, itc_ratio.den, itc_freq / 1000000, (itc_freq / 1000) % 1000); 307 308 if (platform_base_drift != -1) { 309 itc_drift = platform_base_drift*itc_ratio.num/itc_ratio.den; 310 printk("+/-%ldppm\n", itc_drift); 311 } else { 312 itc_drift = -1; 313 printk("\n"); 314 } 315 316 local_cpu_data->proc_freq = (platform_base_freq*proc_ratio.num)/proc_ratio.den; 317 local_cpu_data->itc_freq = itc_freq; 318 local_cpu_data->cyc_per_usec = (itc_freq + USEC_PER_SEC/2) / USEC_PER_SEC; 319 local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT) 320 + itc_freq/2)/itc_freq; 321 322 if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) { 323 #ifdef CONFIG_SMP 324 /* On IA64 in an SMP configuration ITCs are never accurately synchronized. 325 * Jitter compensation requires a cmpxchg which may limit 326 * the scalability of the syscalls for retrieving time. 327 * The ITC synchronization is usually successful to within a few 328 * ITC ticks but this is not a sure thing. If you need to improve 329 * timer performance in SMP situations then boot the kernel with the 330 * "nojitter" option. However, doing so may result in time fluctuating (maybe 331 * even going backward) if the ITC offsets between the individual CPUs 332 * are too large. 333 */ 334 if (!nojitter) 335 itc_jitter_data.itc_jitter = 1; 336 #endif 337 } else 338 /* 339 * ITC is drifty and we have not synchronized the ITCs in smpboot.c. 340 * ITC values may fluctuate significantly between processors. 341 * Clock should not be used for hrtimers. Mark itc as only 342 * useful for boot and testing. 343 * 344 * Note that jitter compensation is off! There is no point of 345 * synchronizing ITCs since they may be large differentials 346 * that change over time. 347 * 348 * The only way to fix this would be to repeatedly sync the 349 * ITCs. Until that time we have to avoid ITC. 350 */ 351 clocksource_itc.rating = 50; 352 353 /* avoid softlock up message when cpu is unplug and plugged again. */ 354 touch_softlockup_watchdog(); 355 356 /* Setup the CPU local timer tick */ 357 ia64_cpu_local_tick(); 358 359 if (!itc_clocksource) { 360 clocksource_register_hz(&clocksource_itc, 361 local_cpu_data->itc_freq); 362 itc_clocksource = &clocksource_itc; 363 } 364 } 365 366 static u64 itc_get_cycles(struct clocksource *cs) 367 { 368 unsigned long lcycle, now, ret; 369 370 if (!itc_jitter_data.itc_jitter) 371 return get_cycles(); 372 373 lcycle = itc_jitter_data.itc_lastcycle; 374 now = get_cycles(); 375 if (lcycle && time_after(lcycle, now)) 376 return lcycle; 377 378 /* 379 * Keep track of the last timer value returned. 380 * In an SMP environment, you could lose out in contention of 381 * cmpxchg. If so, your cmpxchg returns new value which the 382 * winner of contention updated to. Use the new value instead. 383 */ 384 ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now); 385 if (unlikely(ret != lcycle)) 386 return ret; 387 388 return now; 389 } 390 391 void read_persistent_clock64(struct timespec64 *ts) 392 { 393 efi_gettimeofday(ts); 394 } 395 396 void __init 397 time_init (void) 398 { 399 register_percpu_irq(IA64_TIMER_VECTOR, timer_interrupt, IRQF_IRQPOLL, 400 "timer"); 401 ia64_init_itm(); 402 } 403 404 /* 405 * Generic udelay assumes that if preemption is allowed and the thread 406 * migrates to another CPU, that the ITC values are synchronized across 407 * all CPUs. 408 */ 409 static void 410 ia64_itc_udelay (unsigned long usecs) 411 { 412 unsigned long start = ia64_get_itc(); 413 unsigned long end = start + usecs*local_cpu_data->cyc_per_usec; 414 415 while (time_before(ia64_get_itc(), end)) 416 cpu_relax(); 417 } 418 419 void (*ia64_udelay)(unsigned long usecs) = &ia64_itc_udelay; 420 421 void 422 udelay (unsigned long usecs) 423 { 424 (*ia64_udelay)(usecs); 425 } 426 EXPORT_SYMBOL(udelay); 427 428 /* IA64 doesn't cache the timezone */ 429 void update_vsyscall_tz(void) 430 { 431 } 432 433 void update_vsyscall(struct timekeeper *tk) 434 { 435 write_seqcount_begin(&fsyscall_gtod_data.seq); 436 437 /* copy vsyscall data */ 438 fsyscall_gtod_data.clk_mask = tk->tkr_mono.mask; 439 fsyscall_gtod_data.clk_mult = tk->tkr_mono.mult; 440 fsyscall_gtod_data.clk_shift = tk->tkr_mono.shift; 441 fsyscall_gtod_data.clk_fsys_mmio = tk->tkr_mono.clock->archdata.fsys_mmio; 442 fsyscall_gtod_data.clk_cycle_last = tk->tkr_mono.cycle_last; 443 444 fsyscall_gtod_data.wall_time.sec = tk->xtime_sec; 445 fsyscall_gtod_data.wall_time.snsec = tk->tkr_mono.xtime_nsec; 446 447 fsyscall_gtod_data.monotonic_time.sec = tk->xtime_sec 448 + tk->wall_to_monotonic.tv_sec; 449 fsyscall_gtod_data.monotonic_time.snsec = tk->tkr_mono.xtime_nsec 450 + ((u64)tk->wall_to_monotonic.tv_nsec 451 << tk->tkr_mono.shift); 452 453 /* normalize */ 454 while (fsyscall_gtod_data.monotonic_time.snsec >= 455 (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { 456 fsyscall_gtod_data.monotonic_time.snsec -= 457 ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift; 458 fsyscall_gtod_data.monotonic_time.sec++; 459 } 460 461 write_seqcount_end(&fsyscall_gtod_data.seq); 462 } 463 464