1 /* 2 * Common time routines among all ppc machines. 3 * 4 * Written by Cort Dougan (cort@cs.nmt.edu) to merge 5 * Paul Mackerras' version and mine for PReP and Pmac. 6 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net). 7 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com) 8 * 9 * First round of bugfixes by Gabriel Paubert (paubert@iram.es) 10 * to make clock more stable (2.4.0-test5). The only thing 11 * that this code assumes is that the timebases have been synchronized 12 * by firmware on SMP and are never stopped (never do sleep 13 * on SMP then, nap and doze are OK). 14 * 15 * Speeded up do_gettimeofday by getting rid of references to 16 * xtime (which required locks for consistency). (mikejc@us.ibm.com) 17 * 18 * TODO (not necessarily in this file): 19 * - improve precision and reproducibility of timebase frequency 20 * measurement at boot time. 21 * - for astronomical applications: add a new function to get 22 * non ambiguous timestamps even around leap seconds. This needs 23 * a new timestamp format and a good name. 24 * 25 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 26 * "A Kernel Model for Precision Timekeeping" by Dave Mills 27 * 28 * This program is free software; you can redistribute it and/or 29 * modify it under the terms of the GNU General Public License 30 * as published by the Free Software Foundation; either version 31 * 2 of the License, or (at your option) any later version. 32 */ 33 34 #include <linux/errno.h> 35 #include <linux/export.h> 36 #include <linux/sched.h> 37 #include <linux/sched/clock.h> 38 #include <linux/kernel.h> 39 #include <linux/param.h> 40 #include <linux/string.h> 41 #include <linux/mm.h> 42 #include <linux/interrupt.h> 43 #include <linux/timex.h> 44 #include <linux/kernel_stat.h> 45 #include <linux/time.h> 46 #include <linux/clockchips.h> 47 #include <linux/init.h> 48 #include <linux/profile.h> 49 #include <linux/cpu.h> 50 #include <linux/security.h> 51 #include <linux/percpu.h> 52 #include <linux/rtc.h> 53 #include <linux/jiffies.h> 54 #include <linux/posix-timers.h> 55 #include <linux/irq.h> 56 #include <linux/delay.h> 57 #include <linux/irq_work.h> 58 #include <linux/clk-provider.h> 59 #include <linux/suspend.h> 60 #include <linux/rtc.h> 61 #include <linux/sched/cputime.h> 62 #include <linux/processor.h> 63 #include <asm/trace.h> 64 65 #include <asm/io.h> 66 #include <asm/nvram.h> 67 #include <asm/cache.h> 68 #include <asm/machdep.h> 69 #include <linux/uaccess.h> 70 #include <asm/time.h> 71 #include <asm/prom.h> 72 #include <asm/irq.h> 73 #include <asm/div64.h> 74 #include <asm/smp.h> 75 #include <asm/vdso_datapage.h> 76 #include <asm/firmware.h> 77 #include <asm/asm-prototypes.h> 78 79 /* powerpc clocksource/clockevent code */ 80 81 #include <linux/clockchips.h> 82 #include <linux/timekeeper_internal.h> 83 84 static u64 rtc_read(struct clocksource *); 85 static struct clocksource clocksource_rtc = { 86 .name = "rtc", 87 .rating = 400, 88 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 89 .mask = CLOCKSOURCE_MASK(64), 90 .read = rtc_read, 91 }; 92 93 static u64 timebase_read(struct clocksource *); 94 static struct clocksource clocksource_timebase = { 95 .name = "timebase", 96 .rating = 400, 97 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 98 .mask = CLOCKSOURCE_MASK(64), 99 .read = timebase_read, 100 }; 101 102 #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF 103 u64 decrementer_max = DECREMENTER_DEFAULT_MAX; 104 105 static int decrementer_set_next_event(unsigned long evt, 106 struct clock_event_device *dev); 107 static int decrementer_shutdown(struct clock_event_device *evt); 108 109 struct clock_event_device decrementer_clockevent = { 110 .name = "decrementer", 111 .rating = 200, 112 .irq = 0, 113 .set_next_event = decrementer_set_next_event, 114 .set_state_shutdown = decrementer_shutdown, 115 .tick_resume = decrementer_shutdown, 116 .features = CLOCK_EVT_FEAT_ONESHOT | 117 CLOCK_EVT_FEAT_C3STOP, 118 }; 119 EXPORT_SYMBOL(decrementer_clockevent); 120 121 DEFINE_PER_CPU(u64, decrementers_next_tb); 122 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 123 124 #define XSEC_PER_SEC (1024*1024) 125 126 #ifdef CONFIG_PPC64 127 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 128 #else 129 /* compute ((xsec << 12) * max) >> 32 */ 130 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 131 #endif 132 133 unsigned long tb_ticks_per_jiffy; 134 unsigned long tb_ticks_per_usec = 100; /* sane default */ 135 EXPORT_SYMBOL(tb_ticks_per_usec); 136 unsigned long tb_ticks_per_sec; 137 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 138 139 DEFINE_SPINLOCK(rtc_lock); 140 EXPORT_SYMBOL_GPL(rtc_lock); 141 142 static u64 tb_to_ns_scale __read_mostly; 143 static unsigned tb_to_ns_shift __read_mostly; 144 static u64 boot_tb __read_mostly; 145 146 extern struct timezone sys_tz; 147 static long timezone_offset; 148 149 unsigned long ppc_proc_freq; 150 EXPORT_SYMBOL_GPL(ppc_proc_freq); 151 unsigned long ppc_tb_freq; 152 EXPORT_SYMBOL_GPL(ppc_tb_freq); 153 154 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 155 /* 156 * Factor for converting from cputime_t (timebase ticks) to 157 * microseconds. This is stored as 0.64 fixed-point binary fraction. 158 */ 159 u64 __cputime_usec_factor; 160 EXPORT_SYMBOL(__cputime_usec_factor); 161 162 #ifdef CONFIG_PPC_SPLPAR 163 void (*dtl_consumer)(struct dtl_entry *, u64); 164 #endif 165 166 static void calc_cputime_factors(void) 167 { 168 struct div_result res; 169 170 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 171 __cputime_usec_factor = res.result_low; 172 } 173 174 /* 175 * Read the SPURR on systems that have it, otherwise the PURR, 176 * or if that doesn't exist return the timebase value passed in. 177 */ 178 static unsigned long read_spurr(unsigned long tb) 179 { 180 if (cpu_has_feature(CPU_FTR_SPURR)) 181 return mfspr(SPRN_SPURR); 182 if (cpu_has_feature(CPU_FTR_PURR)) 183 return mfspr(SPRN_PURR); 184 return tb; 185 } 186 187 #ifdef CONFIG_PPC_SPLPAR 188 189 /* 190 * Scan the dispatch trace log and count up the stolen time. 191 * Should be called with interrupts disabled. 192 */ 193 static u64 scan_dispatch_log(u64 stop_tb) 194 { 195 u64 i = local_paca->dtl_ridx; 196 struct dtl_entry *dtl = local_paca->dtl_curr; 197 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 198 struct lppaca *vpa = local_paca->lppaca_ptr; 199 u64 tb_delta; 200 u64 stolen = 0; 201 u64 dtb; 202 203 if (!dtl) 204 return 0; 205 206 if (i == be64_to_cpu(vpa->dtl_idx)) 207 return 0; 208 while (i < be64_to_cpu(vpa->dtl_idx)) { 209 dtb = be64_to_cpu(dtl->timebase); 210 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 211 be32_to_cpu(dtl->ready_to_enqueue_time); 212 barrier(); 213 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 214 /* buffer has overflowed */ 215 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 216 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 217 continue; 218 } 219 if (dtb > stop_tb) 220 break; 221 if (dtl_consumer) 222 dtl_consumer(dtl, i); 223 stolen += tb_delta; 224 ++i; 225 ++dtl; 226 if (dtl == dtl_end) 227 dtl = local_paca->dispatch_log; 228 } 229 local_paca->dtl_ridx = i; 230 local_paca->dtl_curr = dtl; 231 return stolen; 232 } 233 234 /* 235 * Accumulate stolen time by scanning the dispatch trace log. 236 * Called on entry from user mode. 237 */ 238 void accumulate_stolen_time(void) 239 { 240 u64 sst, ust; 241 unsigned long save_irq_soft_mask = irq_soft_mask_return(); 242 struct cpu_accounting_data *acct = &local_paca->accounting; 243 244 /* We are called early in the exception entry, before 245 * soft/hard_enabled are sync'ed to the expected state 246 * for the exception. We are hard disabled but the PACA 247 * needs to reflect that so various debug stuff doesn't 248 * complain 249 */ 250 irq_soft_mask_set(IRQS_DISABLED); 251 252 sst = scan_dispatch_log(acct->starttime_user); 253 ust = scan_dispatch_log(acct->starttime); 254 acct->stime -= sst; 255 acct->utime -= ust; 256 acct->steal_time += ust + sst; 257 258 irq_soft_mask_set(save_irq_soft_mask); 259 } 260 261 static inline u64 calculate_stolen_time(u64 stop_tb) 262 { 263 if (!firmware_has_feature(FW_FEATURE_SPLPAR)) 264 return 0; 265 266 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) 267 return scan_dispatch_log(stop_tb); 268 269 return 0; 270 } 271 272 #else /* CONFIG_PPC_SPLPAR */ 273 static inline u64 calculate_stolen_time(u64 stop_tb) 274 { 275 return 0; 276 } 277 278 #endif /* CONFIG_PPC_SPLPAR */ 279 280 /* 281 * Account time for a transition between system, hard irq 282 * or soft irq state. 283 */ 284 static unsigned long vtime_delta(struct task_struct *tsk, 285 unsigned long *stime_scaled, 286 unsigned long *steal_time) 287 { 288 unsigned long now, nowscaled, deltascaled; 289 unsigned long stime; 290 unsigned long utime, utime_scaled; 291 struct cpu_accounting_data *acct = get_accounting(tsk); 292 293 WARN_ON_ONCE(!irqs_disabled()); 294 295 now = mftb(); 296 nowscaled = read_spurr(now); 297 stime = now - acct->starttime; 298 acct->starttime = now; 299 deltascaled = nowscaled - acct->startspurr; 300 acct->startspurr = nowscaled; 301 302 *steal_time = calculate_stolen_time(now); 303 304 utime = acct->utime - acct->utime_sspurr; 305 acct->utime_sspurr = acct->utime; 306 307 /* 308 * Because we don't read the SPURR on every kernel entry/exit, 309 * deltascaled includes both user and system SPURR ticks. 310 * Apportion these ticks to system SPURR ticks and user 311 * SPURR ticks in the same ratio as the system time (delta) 312 * and user time (udelta) values obtained from the timebase 313 * over the same interval. The system ticks get accounted here; 314 * the user ticks get saved up in paca->user_time_scaled to be 315 * used by account_process_tick. 316 */ 317 *stime_scaled = stime; 318 utime_scaled = utime; 319 if (deltascaled != stime + utime) { 320 if (utime) { 321 *stime_scaled = deltascaled * stime / (stime + utime); 322 utime_scaled = deltascaled - *stime_scaled; 323 } else { 324 *stime_scaled = deltascaled; 325 } 326 } 327 acct->utime_scaled += utime_scaled; 328 329 return stime; 330 } 331 332 void vtime_account_system(struct task_struct *tsk) 333 { 334 unsigned long stime, stime_scaled, steal_time; 335 struct cpu_accounting_data *acct = get_accounting(tsk); 336 337 stime = vtime_delta(tsk, &stime_scaled, &steal_time); 338 339 stime -= min(stime, steal_time); 340 acct->steal_time += steal_time; 341 342 if ((tsk->flags & PF_VCPU) && !irq_count()) { 343 acct->gtime += stime; 344 acct->utime_scaled += stime_scaled; 345 } else { 346 if (hardirq_count()) 347 acct->hardirq_time += stime; 348 else if (in_serving_softirq()) 349 acct->softirq_time += stime; 350 else 351 acct->stime += stime; 352 353 acct->stime_scaled += stime_scaled; 354 } 355 } 356 EXPORT_SYMBOL_GPL(vtime_account_system); 357 358 void vtime_account_idle(struct task_struct *tsk) 359 { 360 unsigned long stime, stime_scaled, steal_time; 361 struct cpu_accounting_data *acct = get_accounting(tsk); 362 363 stime = vtime_delta(tsk, &stime_scaled, &steal_time); 364 acct->idle_time += stime + steal_time; 365 } 366 367 /* 368 * Account the whole cputime accumulated in the paca 369 * Must be called with interrupts disabled. 370 * Assumes that vtime_account_system/idle() has been called 371 * recently (i.e. since the last entry from usermode) so that 372 * get_paca()->user_time_scaled is up to date. 373 */ 374 void vtime_flush(struct task_struct *tsk) 375 { 376 struct cpu_accounting_data *acct = get_accounting(tsk); 377 378 if (acct->utime) 379 account_user_time(tsk, cputime_to_nsecs(acct->utime)); 380 381 if (acct->utime_scaled) 382 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled); 383 384 if (acct->gtime) 385 account_guest_time(tsk, cputime_to_nsecs(acct->gtime)); 386 387 if (acct->steal_time) 388 account_steal_time(cputime_to_nsecs(acct->steal_time)); 389 390 if (acct->idle_time) 391 account_idle_time(cputime_to_nsecs(acct->idle_time)); 392 393 if (acct->stime) 394 account_system_index_time(tsk, cputime_to_nsecs(acct->stime), 395 CPUTIME_SYSTEM); 396 if (acct->stime_scaled) 397 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled); 398 399 if (acct->hardirq_time) 400 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time), 401 CPUTIME_IRQ); 402 if (acct->softirq_time) 403 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time), 404 CPUTIME_SOFTIRQ); 405 406 acct->utime = 0; 407 acct->utime_scaled = 0; 408 acct->utime_sspurr = 0; 409 acct->gtime = 0; 410 acct->steal_time = 0; 411 acct->idle_time = 0; 412 acct->stime = 0; 413 acct->stime_scaled = 0; 414 acct->hardirq_time = 0; 415 acct->softirq_time = 0; 416 } 417 418 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 419 #define calc_cputime_factors() 420 #endif 421 422 void __delay(unsigned long loops) 423 { 424 unsigned long start; 425 int diff; 426 427 spin_begin(); 428 if (__USE_RTC()) { 429 start = get_rtcl(); 430 do { 431 /* the RTCL register wraps at 1000000000 */ 432 diff = get_rtcl() - start; 433 if (diff < 0) 434 diff += 1000000000; 435 spin_cpu_relax(); 436 } while (diff < loops); 437 } else { 438 start = get_tbl(); 439 while (get_tbl() - start < loops) 440 spin_cpu_relax(); 441 } 442 spin_end(); 443 } 444 EXPORT_SYMBOL(__delay); 445 446 void udelay(unsigned long usecs) 447 { 448 __delay(tb_ticks_per_usec * usecs); 449 } 450 EXPORT_SYMBOL(udelay); 451 452 #ifdef CONFIG_SMP 453 unsigned long profile_pc(struct pt_regs *regs) 454 { 455 unsigned long pc = instruction_pointer(regs); 456 457 if (in_lock_functions(pc)) 458 return regs->link; 459 460 return pc; 461 } 462 EXPORT_SYMBOL(profile_pc); 463 #endif 464 465 #ifdef CONFIG_IRQ_WORK 466 467 /* 468 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 469 */ 470 #ifdef CONFIG_PPC64 471 static inline unsigned long test_irq_work_pending(void) 472 { 473 unsigned long x; 474 475 asm volatile("lbz %0,%1(13)" 476 : "=r" (x) 477 : "i" (offsetof(struct paca_struct, irq_work_pending))); 478 return x; 479 } 480 481 static inline void set_irq_work_pending_flag(void) 482 { 483 asm volatile("stb %0,%1(13)" : : 484 "r" (1), 485 "i" (offsetof(struct paca_struct, irq_work_pending))); 486 } 487 488 static inline void clear_irq_work_pending(void) 489 { 490 asm volatile("stb %0,%1(13)" : : 491 "r" (0), 492 "i" (offsetof(struct paca_struct, irq_work_pending))); 493 } 494 495 void arch_irq_work_raise(void) 496 { 497 preempt_disable(); 498 set_irq_work_pending_flag(); 499 /* 500 * Non-nmi code running with interrupts disabled will replay 501 * irq_happened before it re-enables interrupts, so setthe 502 * decrementer there instead of causing a hardware exception 503 * which would immediately hit the masked interrupt handler 504 * and have the net effect of setting the decrementer in 505 * irq_happened. 506 * 507 * NMI interrupts can not check this when they return, so the 508 * decrementer hardware exception is raised, which will fire 509 * when interrupts are next enabled. 510 * 511 * BookE does not support this yet, it must audit all NMI 512 * interrupt handlers to ensure they call nmi_enter() so this 513 * check would be correct. 514 */ 515 if (IS_ENABLED(CONFIG_BOOKE) || !irqs_disabled() || in_nmi()) { 516 set_dec(1); 517 } else { 518 hard_irq_disable(); 519 local_paca->irq_happened |= PACA_IRQ_DEC; 520 } 521 preempt_enable(); 522 } 523 524 #else /* 32-bit */ 525 526 DEFINE_PER_CPU(u8, irq_work_pending); 527 528 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 529 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 530 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 531 532 void arch_irq_work_raise(void) 533 { 534 preempt_disable(); 535 set_irq_work_pending_flag(); 536 set_dec(1); 537 preempt_enable(); 538 } 539 540 #endif /* 32 vs 64 bit */ 541 542 #else /* CONFIG_IRQ_WORK */ 543 544 #define test_irq_work_pending() 0 545 #define clear_irq_work_pending() 546 547 #endif /* CONFIG_IRQ_WORK */ 548 549 /* 550 * timer_interrupt - gets called when the decrementer overflows, 551 * with interrupts disabled. 552 */ 553 void timer_interrupt(struct pt_regs *regs) 554 { 555 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 556 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 557 struct pt_regs *old_regs; 558 u64 now; 559 560 /* Some implementations of hotplug will get timer interrupts while 561 * offline, just ignore these and we also need to set 562 * decrementers_next_tb as MAX to make sure __check_irq_replay 563 * don't replay timer interrupt when return, otherwise we'll trap 564 * here infinitely :( 565 */ 566 if (unlikely(!cpu_online(smp_processor_id()))) { 567 *next_tb = ~(u64)0; 568 set_dec(decrementer_max); 569 return; 570 } 571 572 /* Ensure a positive value is written to the decrementer, or else 573 * some CPUs will continue to take decrementer exceptions. When the 574 * PPC_WATCHDOG (decrementer based) is configured, keep this at most 575 * 31 bits, which is about 4 seconds on most systems, which gives 576 * the watchdog a chance of catching timer interrupt hard lockups. 577 */ 578 if (IS_ENABLED(CONFIG_PPC_WATCHDOG)) 579 set_dec(0x7fffffff); 580 else 581 set_dec(decrementer_max); 582 583 /* Conditionally hard-enable interrupts now that the DEC has been 584 * bumped to its maximum value 585 */ 586 may_hard_irq_enable(); 587 588 589 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 590 if (atomic_read(&ppc_n_lost_interrupts) != 0) 591 do_IRQ(regs); 592 #endif 593 594 old_regs = set_irq_regs(regs); 595 irq_enter(); 596 trace_timer_interrupt_entry(regs); 597 598 if (test_irq_work_pending()) { 599 clear_irq_work_pending(); 600 irq_work_run(); 601 } 602 603 now = get_tb_or_rtc(); 604 if (now >= *next_tb) { 605 *next_tb = ~(u64)0; 606 if (evt->event_handler) 607 evt->event_handler(evt); 608 __this_cpu_inc(irq_stat.timer_irqs_event); 609 } else { 610 now = *next_tb - now; 611 if (now <= decrementer_max) 612 set_dec(now); 613 /* We may have raced with new irq work */ 614 if (test_irq_work_pending()) 615 set_dec(1); 616 __this_cpu_inc(irq_stat.timer_irqs_others); 617 } 618 619 trace_timer_interrupt_exit(regs); 620 irq_exit(); 621 set_irq_regs(old_regs); 622 } 623 EXPORT_SYMBOL(timer_interrupt); 624 625 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 626 void timer_broadcast_interrupt(void) 627 { 628 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 629 630 *next_tb = ~(u64)0; 631 tick_receive_broadcast(); 632 __this_cpu_inc(irq_stat.broadcast_irqs_event); 633 } 634 #endif 635 636 /* 637 * Hypervisor decrementer interrupts shouldn't occur but are sometimes 638 * left pending on exit from a KVM guest. We don't need to do anything 639 * to clear them, as they are edge-triggered. 640 */ 641 void hdec_interrupt(struct pt_regs *regs) 642 { 643 } 644 645 #ifdef CONFIG_SUSPEND 646 static void generic_suspend_disable_irqs(void) 647 { 648 /* Disable the decrementer, so that it doesn't interfere 649 * with suspending. 650 */ 651 652 set_dec(decrementer_max); 653 local_irq_disable(); 654 set_dec(decrementer_max); 655 } 656 657 static void generic_suspend_enable_irqs(void) 658 { 659 local_irq_enable(); 660 } 661 662 /* Overrides the weak version in kernel/power/main.c */ 663 void arch_suspend_disable_irqs(void) 664 { 665 if (ppc_md.suspend_disable_irqs) 666 ppc_md.suspend_disable_irqs(); 667 generic_suspend_disable_irqs(); 668 } 669 670 /* Overrides the weak version in kernel/power/main.c */ 671 void arch_suspend_enable_irqs(void) 672 { 673 generic_suspend_enable_irqs(); 674 if (ppc_md.suspend_enable_irqs) 675 ppc_md.suspend_enable_irqs(); 676 } 677 #endif 678 679 unsigned long long tb_to_ns(unsigned long long ticks) 680 { 681 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 682 } 683 EXPORT_SYMBOL_GPL(tb_to_ns); 684 685 /* 686 * Scheduler clock - returns current time in nanosec units. 687 * 688 * Note: mulhdu(a, b) (multiply high double unsigned) returns 689 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 690 * are 64-bit unsigned numbers. 691 */ 692 notrace unsigned long long sched_clock(void) 693 { 694 if (__USE_RTC()) 695 return get_rtc(); 696 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 697 } 698 699 700 #ifdef CONFIG_PPC_PSERIES 701 702 /* 703 * Running clock - attempts to give a view of time passing for a virtualised 704 * kernels. 705 * Uses the VTB register if available otherwise a next best guess. 706 */ 707 unsigned long long running_clock(void) 708 { 709 /* 710 * Don't read the VTB as a host since KVM does not switch in host 711 * timebase into the VTB when it takes a guest off the CPU, reading the 712 * VTB would result in reading 'last switched out' guest VTB. 713 * 714 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 715 * would be unsafe to rely only on the #ifdef above. 716 */ 717 if (firmware_has_feature(FW_FEATURE_LPAR) && 718 cpu_has_feature(CPU_FTR_ARCH_207S)) 719 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 720 721 /* 722 * This is a next best approximation without a VTB. 723 * On a host which is running bare metal there should never be any stolen 724 * time and on a host which doesn't do any virtualisation TB *should* equal 725 * VTB so it makes no difference anyway. 726 */ 727 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL]; 728 } 729 #endif 730 731 static int __init get_freq(char *name, int cells, unsigned long *val) 732 { 733 struct device_node *cpu; 734 const __be32 *fp; 735 int found = 0; 736 737 /* The cpu node should have timebase and clock frequency properties */ 738 cpu = of_find_node_by_type(NULL, "cpu"); 739 740 if (cpu) { 741 fp = of_get_property(cpu, name, NULL); 742 if (fp) { 743 found = 1; 744 *val = of_read_ulong(fp, cells); 745 } 746 747 of_node_put(cpu); 748 } 749 750 return found; 751 } 752 753 static void start_cpu_decrementer(void) 754 { 755 #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) 756 unsigned int tcr; 757 758 /* Clear any pending timer interrupts */ 759 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 760 761 tcr = mfspr(SPRN_TCR); 762 /* 763 * The watchdog may have already been enabled by u-boot. So leave 764 * TRC[WP] (Watchdog Period) alone. 765 */ 766 tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */ 767 tcr |= TCR_DIE; /* Enable decrementer */ 768 mtspr(SPRN_TCR, tcr); 769 #endif 770 } 771 772 void __init generic_calibrate_decr(void) 773 { 774 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 775 776 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 777 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 778 779 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 780 "(not found)\n"); 781 } 782 783 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 784 785 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 786 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 787 788 printk(KERN_ERR "WARNING: Estimating processor frequency " 789 "(not found)\n"); 790 } 791 } 792 793 int update_persistent_clock64(struct timespec64 now) 794 { 795 struct rtc_time tm; 796 797 if (!ppc_md.set_rtc_time) 798 return -ENODEV; 799 800 rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm); 801 802 return ppc_md.set_rtc_time(&tm); 803 } 804 805 static void __read_persistent_clock(struct timespec64 *ts) 806 { 807 struct rtc_time tm; 808 static int first = 1; 809 810 ts->tv_nsec = 0; 811 /* XXX this is a litle fragile but will work okay in the short term */ 812 if (first) { 813 first = 0; 814 if (ppc_md.time_init) 815 timezone_offset = ppc_md.time_init(); 816 817 /* get_boot_time() isn't guaranteed to be safe to call late */ 818 if (ppc_md.get_boot_time) { 819 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 820 return; 821 } 822 } 823 if (!ppc_md.get_rtc_time) { 824 ts->tv_sec = 0; 825 return; 826 } 827 ppc_md.get_rtc_time(&tm); 828 829 ts->tv_sec = rtc_tm_to_time64(&tm); 830 } 831 832 void read_persistent_clock64(struct timespec64 *ts) 833 { 834 __read_persistent_clock(ts); 835 836 /* Sanitize it in case real time clock is set below EPOCH */ 837 if (ts->tv_sec < 0) { 838 ts->tv_sec = 0; 839 ts->tv_nsec = 0; 840 } 841 842 } 843 844 /* clocksource code */ 845 static notrace u64 rtc_read(struct clocksource *cs) 846 { 847 return (u64)get_rtc(); 848 } 849 850 static notrace u64 timebase_read(struct clocksource *cs) 851 { 852 return (u64)get_tb(); 853 } 854 855 856 void update_vsyscall(struct timekeeper *tk) 857 { 858 struct timespec xt; 859 struct clocksource *clock = tk->tkr_mono.clock; 860 u32 mult = tk->tkr_mono.mult; 861 u32 shift = tk->tkr_mono.shift; 862 u64 cycle_last = tk->tkr_mono.cycle_last; 863 u64 new_tb_to_xs, new_stamp_xsec; 864 u64 frac_sec; 865 866 if (clock != &clocksource_timebase) 867 return; 868 869 xt.tv_sec = tk->xtime_sec; 870 xt.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift); 871 872 /* Make userspace gettimeofday spin until we're done. */ 873 ++vdso_data->tb_update_count; 874 smp_mb(); 875 876 /* 877 * This computes ((2^20 / 1e9) * mult) >> shift as a 878 * 0.64 fixed-point fraction. 879 * The computation in the else clause below won't overflow 880 * (as long as the timebase frequency is >= 1.049 MHz) 881 * but loses precision because we lose the low bits of the constant 882 * in the shift. Note that 19342813113834067 ~= 2^(20+64) / 1e9. 883 * For a shift of 24 the error is about 0.5e-9, or about 0.5ns 884 * over a second. (Shift values are usually 22, 23 or 24.) 885 * For high frequency clocks such as the 512MHz timebase clock 886 * on POWER[6789], the mult value is small (e.g. 32768000) 887 * and so we can shift the constant by 16 initially 888 * (295147905179 ~= 2^(20+64-16) / 1e9) and then do the 889 * remaining shifts after the multiplication, which gives a 890 * more accurate result (e.g. with mult = 32768000, shift = 24, 891 * the error is only about 1.2e-12, or 0.7ns over 10 minutes). 892 */ 893 if (mult <= 62500000 && clock->shift >= 16) 894 new_tb_to_xs = ((u64) mult * 295147905179ULL) >> (clock->shift - 16); 895 else 896 new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); 897 898 /* 899 * Compute the fractional second in units of 2^-32 seconds. 900 * The fractional second is tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift 901 * in nanoseconds, so multiplying that by 2^32 / 1e9 gives 902 * it in units of 2^-32 seconds. 903 * We assume shift <= 32 because clocks_calc_mult_shift() 904 * generates shift values in the range 0 - 32. 905 */ 906 frac_sec = tk->tkr_mono.xtime_nsec << (32 - shift); 907 do_div(frac_sec, NSEC_PER_SEC); 908 909 /* 910 * Work out new stamp_xsec value for any legacy users of systemcfg. 911 * stamp_xsec is in units of 2^-20 seconds. 912 */ 913 new_stamp_xsec = frac_sec >> 12; 914 new_stamp_xsec += tk->xtime_sec * XSEC_PER_SEC; 915 916 /* 917 * tb_update_count is used to allow the userspace gettimeofday code 918 * to assure itself that it sees a consistent view of the tb_to_xs and 919 * stamp_xsec variables. It reads the tb_update_count, then reads 920 * tb_to_xs and stamp_xsec and then reads tb_update_count again. If 921 * the two values of tb_update_count match and are even then the 922 * tb_to_xs and stamp_xsec values are consistent. If not, then it 923 * loops back and reads them again until this criteria is met. 924 */ 925 vdso_data->tb_orig_stamp = cycle_last; 926 vdso_data->stamp_xsec = new_stamp_xsec; 927 vdso_data->tb_to_xs = new_tb_to_xs; 928 vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec; 929 vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec; 930 vdso_data->stamp_xtime = xt; 931 vdso_data->stamp_sec_fraction = frac_sec; 932 smp_wmb(); 933 ++(vdso_data->tb_update_count); 934 } 935 936 void update_vsyscall_tz(void) 937 { 938 vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; 939 vdso_data->tz_dsttime = sys_tz.tz_dsttime; 940 } 941 942 static void __init clocksource_init(void) 943 { 944 struct clocksource *clock; 945 946 if (__USE_RTC()) 947 clock = &clocksource_rtc; 948 else 949 clock = &clocksource_timebase; 950 951 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 952 printk(KERN_ERR "clocksource: %s is already registered\n", 953 clock->name); 954 return; 955 } 956 957 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 958 clock->name, clock->mult, clock->shift); 959 } 960 961 static int decrementer_set_next_event(unsigned long evt, 962 struct clock_event_device *dev) 963 { 964 __this_cpu_write(decrementers_next_tb, get_tb_or_rtc() + evt); 965 set_dec(evt); 966 967 /* We may have raced with new irq work */ 968 if (test_irq_work_pending()) 969 set_dec(1); 970 971 return 0; 972 } 973 974 static int decrementer_shutdown(struct clock_event_device *dev) 975 { 976 decrementer_set_next_event(decrementer_max, dev); 977 return 0; 978 } 979 980 static void register_decrementer_clockevent(int cpu) 981 { 982 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 983 984 *dec = decrementer_clockevent; 985 dec->cpumask = cpumask_of(cpu); 986 987 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 988 dec->name, dec->mult, dec->shift, cpu); 989 990 clockevents_register_device(dec); 991 } 992 993 static void enable_large_decrementer(void) 994 { 995 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 996 return; 997 998 if (decrementer_max <= DECREMENTER_DEFAULT_MAX) 999 return; 1000 1001 /* 1002 * If we're running as the hypervisor we need to enable the LD manually 1003 * otherwise firmware should have done it for us. 1004 */ 1005 if (cpu_has_feature(CPU_FTR_HVMODE)) 1006 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); 1007 } 1008 1009 static void __init set_decrementer_max(void) 1010 { 1011 struct device_node *cpu; 1012 u32 bits = 32; 1013 1014 /* Prior to ISAv3 the decrementer is always 32 bit */ 1015 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 1016 return; 1017 1018 cpu = of_find_node_by_type(NULL, "cpu"); 1019 1020 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { 1021 if (bits > 64 || bits < 32) { 1022 pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); 1023 bits = 32; 1024 } 1025 1026 /* calculate the signed maximum given this many bits */ 1027 decrementer_max = (1ul << (bits - 1)) - 1; 1028 } 1029 1030 of_node_put(cpu); 1031 1032 pr_info("time_init: %u bit decrementer (max: %llx)\n", 1033 bits, decrementer_max); 1034 } 1035 1036 static void __init init_decrementer_clockevent(void) 1037 { 1038 int cpu = smp_processor_id(); 1039 1040 clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); 1041 1042 decrementer_clockevent.max_delta_ns = 1043 clockevent_delta2ns(decrementer_max, &decrementer_clockevent); 1044 decrementer_clockevent.max_delta_ticks = decrementer_max; 1045 decrementer_clockevent.min_delta_ns = 1046 clockevent_delta2ns(2, &decrementer_clockevent); 1047 decrementer_clockevent.min_delta_ticks = 2; 1048 1049 register_decrementer_clockevent(cpu); 1050 } 1051 1052 void secondary_cpu_time_init(void) 1053 { 1054 /* Enable and test the large decrementer for this cpu */ 1055 enable_large_decrementer(); 1056 1057 /* Start the decrementer on CPUs that have manual control 1058 * such as BookE 1059 */ 1060 start_cpu_decrementer(); 1061 1062 /* FIME: Should make unrelatred change to move snapshot_timebase 1063 * call here ! */ 1064 register_decrementer_clockevent(smp_processor_id()); 1065 } 1066 1067 /* This function is only called on the boot processor */ 1068 void __init time_init(void) 1069 { 1070 struct div_result res; 1071 u64 scale; 1072 unsigned shift; 1073 1074 if (__USE_RTC()) { 1075 /* 601 processor: dec counts down by 128 every 128ns */ 1076 ppc_tb_freq = 1000000000; 1077 } else { 1078 /* Normal PowerPC with timebase register */ 1079 ppc_md.calibrate_decr(); 1080 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 1081 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 1082 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 1083 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 1084 } 1085 1086 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 1087 tb_ticks_per_sec = ppc_tb_freq; 1088 tb_ticks_per_usec = ppc_tb_freq / 1000000; 1089 calc_cputime_factors(); 1090 1091 /* 1092 * Compute scale factor for sched_clock. 1093 * The calibrate_decr() function has set tb_ticks_per_sec, 1094 * which is the timebase frequency. 1095 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1096 * the 128-bit result as a 64.64 fixed-point number. 1097 * We then shift that number right until it is less than 1.0, 1098 * giving us the scale factor and shift count to use in 1099 * sched_clock(). 1100 */ 1101 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1102 scale = res.result_low; 1103 for (shift = 0; res.result_high != 0; ++shift) { 1104 scale = (scale >> 1) | (res.result_high << 63); 1105 res.result_high >>= 1; 1106 } 1107 tb_to_ns_scale = scale; 1108 tb_to_ns_shift = shift; 1109 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1110 boot_tb = get_tb_or_rtc(); 1111 1112 /* If platform provided a timezone (pmac), we correct the time */ 1113 if (timezone_offset) { 1114 sys_tz.tz_minuteswest = -timezone_offset / 60; 1115 sys_tz.tz_dsttime = 0; 1116 } 1117 1118 vdso_data->tb_update_count = 0; 1119 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1120 1121 /* initialise and enable the large decrementer (if we have one) */ 1122 set_decrementer_max(); 1123 enable_large_decrementer(); 1124 1125 /* Start the decrementer on CPUs that have manual control 1126 * such as BookE 1127 */ 1128 start_cpu_decrementer(); 1129 1130 /* Register the clocksource */ 1131 clocksource_init(); 1132 1133 init_decrementer_clockevent(); 1134 tick_setup_hrtimer_broadcast(); 1135 1136 #ifdef CONFIG_COMMON_CLK 1137 of_clk_init(NULL); 1138 #endif 1139 } 1140 1141 /* 1142 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1143 * result. 1144 */ 1145 void div128_by_32(u64 dividend_high, u64 dividend_low, 1146 unsigned divisor, struct div_result *dr) 1147 { 1148 unsigned long a, b, c, d; 1149 unsigned long w, x, y, z; 1150 u64 ra, rb, rc; 1151 1152 a = dividend_high >> 32; 1153 b = dividend_high & 0xffffffff; 1154 c = dividend_low >> 32; 1155 d = dividend_low & 0xffffffff; 1156 1157 w = a / divisor; 1158 ra = ((u64)(a - (w * divisor)) << 32) + b; 1159 1160 rb = ((u64) do_div(ra, divisor) << 32) + c; 1161 x = ra; 1162 1163 rc = ((u64) do_div(rb, divisor) << 32) + d; 1164 y = rb; 1165 1166 do_div(rc, divisor); 1167 z = rc; 1168 1169 dr->result_high = ((u64)w << 32) + x; 1170 dr->result_low = ((u64)y << 32) + z; 1171 1172 } 1173 1174 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1175 void calibrate_delay(void) 1176 { 1177 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1178 * as the number of __delay(1) in a jiffy, so make it so 1179 */ 1180 loops_per_jiffy = tb_ticks_per_jiffy; 1181 } 1182 1183 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 1184 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 1185 { 1186 ppc_md.get_rtc_time(tm); 1187 return 0; 1188 } 1189 1190 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 1191 { 1192 if (!ppc_md.set_rtc_time) 1193 return -EOPNOTSUPP; 1194 1195 if (ppc_md.set_rtc_time(tm) < 0) 1196 return -EOPNOTSUPP; 1197 1198 return 0; 1199 } 1200 1201 static const struct rtc_class_ops rtc_generic_ops = { 1202 .read_time = rtc_generic_get_time, 1203 .set_time = rtc_generic_set_time, 1204 }; 1205 1206 static int __init rtc_init(void) 1207 { 1208 struct platform_device *pdev; 1209 1210 if (!ppc_md.get_rtc_time) 1211 return -ENODEV; 1212 1213 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 1214 &rtc_generic_ops, 1215 sizeof(rtc_generic_ops)); 1216 1217 return PTR_ERR_OR_ZERO(pdev); 1218 } 1219 1220 device_initcall(rtc_init); 1221 #endif 1222