1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Common time routines among all ppc machines. 4 * 5 * Written by Cort Dougan (cort@cs.nmt.edu) to merge 6 * Paul Mackerras' version and mine for PReP and Pmac. 7 * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net). 8 * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com) 9 * 10 * First round of bugfixes by Gabriel Paubert (paubert@iram.es) 11 * to make clock more stable (2.4.0-test5). The only thing 12 * that this code assumes is that the timebases have been synchronized 13 * by firmware on SMP and are never stopped (never do sleep 14 * on SMP then, nap and doze are OK). 15 * 16 * Speeded up do_gettimeofday by getting rid of references to 17 * xtime (which required locks for consistency). (mikejc@us.ibm.com) 18 * 19 * TODO (not necessarily in this file): 20 * - improve precision and reproducibility of timebase frequency 21 * measurement at boot time. 22 * - for astronomical applications: add a new function to get 23 * non ambiguous timestamps even around leap seconds. This needs 24 * a new timestamp format and a good name. 25 * 26 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 27 * "A Kernel Model for Precision Timekeeping" by Dave Mills 28 */ 29 30 #include <linux/errno.h> 31 #include <linux/export.h> 32 #include <linux/sched.h> 33 #include <linux/sched/clock.h> 34 #include <linux/sched/cputime.h> 35 #include <linux/kernel.h> 36 #include <linux/param.h> 37 #include <linux/string.h> 38 #include <linux/mm.h> 39 #include <linux/interrupt.h> 40 #include <linux/timex.h> 41 #include <linux/kernel_stat.h> 42 #include <linux/time.h> 43 #include <linux/init.h> 44 #include <linux/profile.h> 45 #include <linux/cpu.h> 46 #include <linux/security.h> 47 #include <linux/percpu.h> 48 #include <linux/rtc.h> 49 #include <linux/jiffies.h> 50 #include <linux/posix-timers.h> 51 #include <linux/irq.h> 52 #include <linux/delay.h> 53 #include <linux/irq_work.h> 54 #include <linux/of_clk.h> 55 #include <linux/suspend.h> 56 #include <linux/processor.h> 57 #include <asm/trace.h> 58 59 #include <asm/interrupt.h> 60 #include <asm/io.h> 61 #include <asm/nvram.h> 62 #include <asm/cache.h> 63 #include <asm/machdep.h> 64 #include <linux/uaccess.h> 65 #include <asm/time.h> 66 #include <asm/prom.h> 67 #include <asm/irq.h> 68 #include <asm/div64.h> 69 #include <asm/smp.h> 70 #include <asm/vdso_datapage.h> 71 #include <asm/firmware.h> 72 #include <asm/asm-prototypes.h> 73 74 /* powerpc clocksource/clockevent code */ 75 76 #include <linux/clockchips.h> 77 #include <linux/timekeeper_internal.h> 78 79 static u64 timebase_read(struct clocksource *); 80 static struct clocksource clocksource_timebase = { 81 .name = "timebase", 82 .rating = 400, 83 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 84 .mask = CLOCKSOURCE_MASK(64), 85 .read = timebase_read, 86 .vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER, 87 }; 88 89 #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF 90 u64 decrementer_max = DECREMENTER_DEFAULT_MAX; 91 EXPORT_SYMBOL_GPL(decrementer_max); /* for KVM HDEC */ 92 93 static int decrementer_set_next_event(unsigned long evt, 94 struct clock_event_device *dev); 95 static int decrementer_shutdown(struct clock_event_device *evt); 96 97 struct clock_event_device decrementer_clockevent = { 98 .name = "decrementer", 99 .rating = 200, 100 .irq = 0, 101 .set_next_event = decrementer_set_next_event, 102 .set_state_oneshot_stopped = decrementer_shutdown, 103 .set_state_shutdown = decrementer_shutdown, 104 .tick_resume = decrementer_shutdown, 105 .features = CLOCK_EVT_FEAT_ONESHOT | 106 CLOCK_EVT_FEAT_C3STOP, 107 }; 108 EXPORT_SYMBOL(decrementer_clockevent); 109 110 DEFINE_PER_CPU(u64, decrementers_next_tb); 111 EXPORT_SYMBOL_GPL(decrementers_next_tb); 112 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 113 114 #define XSEC_PER_SEC (1024*1024) 115 116 #ifdef CONFIG_PPC64 117 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 118 #else 119 /* compute ((xsec << 12) * max) >> 32 */ 120 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 121 #endif 122 123 unsigned long tb_ticks_per_jiffy; 124 unsigned long tb_ticks_per_usec = 100; /* sane default */ 125 EXPORT_SYMBOL(tb_ticks_per_usec); 126 unsigned long tb_ticks_per_sec; 127 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 128 129 DEFINE_SPINLOCK(rtc_lock); 130 EXPORT_SYMBOL_GPL(rtc_lock); 131 132 static u64 tb_to_ns_scale __read_mostly; 133 static unsigned tb_to_ns_shift __read_mostly; 134 static u64 boot_tb __read_mostly; 135 136 extern struct timezone sys_tz; 137 static long timezone_offset; 138 139 unsigned long ppc_proc_freq; 140 EXPORT_SYMBOL_GPL(ppc_proc_freq); 141 unsigned long ppc_tb_freq; 142 EXPORT_SYMBOL_GPL(ppc_tb_freq); 143 144 bool tb_invalid; 145 146 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 147 /* 148 * Factor for converting from cputime_t (timebase ticks) to 149 * microseconds. This is stored as 0.64 fixed-point binary fraction. 150 */ 151 u64 __cputime_usec_factor; 152 EXPORT_SYMBOL(__cputime_usec_factor); 153 154 #ifdef CONFIG_PPC_SPLPAR 155 void (*dtl_consumer)(struct dtl_entry *, u64); 156 #endif 157 158 static void calc_cputime_factors(void) 159 { 160 struct div_result res; 161 162 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 163 __cputime_usec_factor = res.result_low; 164 } 165 166 /* 167 * Read the SPURR on systems that have it, otherwise the PURR, 168 * or if that doesn't exist return the timebase value passed in. 169 */ 170 static inline unsigned long read_spurr(unsigned long tb) 171 { 172 if (cpu_has_feature(CPU_FTR_SPURR)) 173 return mfspr(SPRN_SPURR); 174 if (cpu_has_feature(CPU_FTR_PURR)) 175 return mfspr(SPRN_PURR); 176 return tb; 177 } 178 179 #ifdef CONFIG_PPC_SPLPAR 180 181 #include <asm/dtl.h> 182 183 /* 184 * Scan the dispatch trace log and count up the stolen time. 185 * Should be called with interrupts disabled. 186 */ 187 static u64 scan_dispatch_log(u64 stop_tb) 188 { 189 u64 i = local_paca->dtl_ridx; 190 struct dtl_entry *dtl = local_paca->dtl_curr; 191 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 192 struct lppaca *vpa = local_paca->lppaca_ptr; 193 u64 tb_delta; 194 u64 stolen = 0; 195 u64 dtb; 196 197 if (!dtl) 198 return 0; 199 200 if (i == be64_to_cpu(vpa->dtl_idx)) 201 return 0; 202 while (i < be64_to_cpu(vpa->dtl_idx)) { 203 dtb = be64_to_cpu(dtl->timebase); 204 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 205 be32_to_cpu(dtl->ready_to_enqueue_time); 206 barrier(); 207 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 208 /* buffer has overflowed */ 209 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 210 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 211 continue; 212 } 213 if (dtb > stop_tb) 214 break; 215 if (dtl_consumer) 216 dtl_consumer(dtl, i); 217 stolen += tb_delta; 218 ++i; 219 ++dtl; 220 if (dtl == dtl_end) 221 dtl = local_paca->dispatch_log; 222 } 223 local_paca->dtl_ridx = i; 224 local_paca->dtl_curr = dtl; 225 return stolen; 226 } 227 228 /* 229 * Accumulate stolen time by scanning the dispatch trace log. 230 * Called on entry from user mode. 231 */ 232 void notrace accumulate_stolen_time(void) 233 { 234 u64 sst, ust; 235 struct cpu_accounting_data *acct = &local_paca->accounting; 236 237 sst = scan_dispatch_log(acct->starttime_user); 238 ust = scan_dispatch_log(acct->starttime); 239 acct->stime -= sst; 240 acct->utime -= ust; 241 acct->steal_time += ust + sst; 242 } 243 244 static inline u64 calculate_stolen_time(u64 stop_tb) 245 { 246 if (!firmware_has_feature(FW_FEATURE_SPLPAR)) 247 return 0; 248 249 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) 250 return scan_dispatch_log(stop_tb); 251 252 return 0; 253 } 254 255 #else /* CONFIG_PPC_SPLPAR */ 256 static inline u64 calculate_stolen_time(u64 stop_tb) 257 { 258 return 0; 259 } 260 261 #endif /* CONFIG_PPC_SPLPAR */ 262 263 /* 264 * Account time for a transition between system, hard irq 265 * or soft irq state. 266 */ 267 static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct, 268 unsigned long now, unsigned long stime) 269 { 270 unsigned long stime_scaled = 0; 271 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 272 unsigned long nowscaled, deltascaled; 273 unsigned long utime, utime_scaled; 274 275 nowscaled = read_spurr(now); 276 deltascaled = nowscaled - acct->startspurr; 277 acct->startspurr = nowscaled; 278 utime = acct->utime - acct->utime_sspurr; 279 acct->utime_sspurr = acct->utime; 280 281 /* 282 * Because we don't read the SPURR on every kernel entry/exit, 283 * deltascaled includes both user and system SPURR ticks. 284 * Apportion these ticks to system SPURR ticks and user 285 * SPURR ticks in the same ratio as the system time (delta) 286 * and user time (udelta) values obtained from the timebase 287 * over the same interval. The system ticks get accounted here; 288 * the user ticks get saved up in paca->user_time_scaled to be 289 * used by account_process_tick. 290 */ 291 stime_scaled = stime; 292 utime_scaled = utime; 293 if (deltascaled != stime + utime) { 294 if (utime) { 295 stime_scaled = deltascaled * stime / (stime + utime); 296 utime_scaled = deltascaled - stime_scaled; 297 } else { 298 stime_scaled = deltascaled; 299 } 300 } 301 acct->utime_scaled += utime_scaled; 302 #endif 303 304 return stime_scaled; 305 } 306 307 static unsigned long vtime_delta(struct cpu_accounting_data *acct, 308 unsigned long *stime_scaled, 309 unsigned long *steal_time) 310 { 311 unsigned long now, stime; 312 313 WARN_ON_ONCE(!irqs_disabled()); 314 315 now = mftb(); 316 stime = now - acct->starttime; 317 acct->starttime = now; 318 319 *stime_scaled = vtime_delta_scaled(acct, now, stime); 320 321 *steal_time = calculate_stolen_time(now); 322 323 return stime; 324 } 325 326 static void vtime_delta_kernel(struct cpu_accounting_data *acct, 327 unsigned long *stime, unsigned long *stime_scaled) 328 { 329 unsigned long steal_time; 330 331 *stime = vtime_delta(acct, stime_scaled, &steal_time); 332 *stime -= min(*stime, steal_time); 333 acct->steal_time += steal_time; 334 } 335 336 void vtime_account_kernel(struct task_struct *tsk) 337 { 338 struct cpu_accounting_data *acct = get_accounting(tsk); 339 unsigned long stime, stime_scaled; 340 341 vtime_delta_kernel(acct, &stime, &stime_scaled); 342 343 if (tsk->flags & PF_VCPU) { 344 acct->gtime += stime; 345 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 346 acct->utime_scaled += stime_scaled; 347 #endif 348 } else { 349 acct->stime += stime; 350 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 351 acct->stime_scaled += stime_scaled; 352 #endif 353 } 354 } 355 EXPORT_SYMBOL_GPL(vtime_account_kernel); 356 357 void vtime_account_idle(struct task_struct *tsk) 358 { 359 unsigned long stime, stime_scaled, steal_time; 360 struct cpu_accounting_data *acct = get_accounting(tsk); 361 362 stime = vtime_delta(acct, &stime_scaled, &steal_time); 363 acct->idle_time += stime + steal_time; 364 } 365 366 static void vtime_account_irq_field(struct cpu_accounting_data *acct, 367 unsigned long *field) 368 { 369 unsigned long stime, stime_scaled; 370 371 vtime_delta_kernel(acct, &stime, &stime_scaled); 372 *field += stime; 373 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 374 acct->stime_scaled += stime_scaled; 375 #endif 376 } 377 378 void vtime_account_softirq(struct task_struct *tsk) 379 { 380 struct cpu_accounting_data *acct = get_accounting(tsk); 381 vtime_account_irq_field(acct, &acct->softirq_time); 382 } 383 384 void vtime_account_hardirq(struct task_struct *tsk) 385 { 386 struct cpu_accounting_data *acct = get_accounting(tsk); 387 vtime_account_irq_field(acct, &acct->hardirq_time); 388 } 389 390 static void vtime_flush_scaled(struct task_struct *tsk, 391 struct cpu_accounting_data *acct) 392 { 393 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 394 if (acct->utime_scaled) 395 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled); 396 if (acct->stime_scaled) 397 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled); 398 399 acct->utime_scaled = 0; 400 acct->utime_sspurr = 0; 401 acct->stime_scaled = 0; 402 #endif 403 } 404 405 /* 406 * Account the whole cputime accumulated in the paca 407 * Must be called with interrupts disabled. 408 * Assumes that vtime_account_kernel/idle() has been called 409 * recently (i.e. since the last entry from usermode) so that 410 * get_paca()->user_time_scaled is up to date. 411 */ 412 void vtime_flush(struct task_struct *tsk) 413 { 414 struct cpu_accounting_data *acct = get_accounting(tsk); 415 416 if (acct->utime) 417 account_user_time(tsk, cputime_to_nsecs(acct->utime)); 418 419 if (acct->gtime) 420 account_guest_time(tsk, cputime_to_nsecs(acct->gtime)); 421 422 if (IS_ENABLED(CONFIG_PPC_SPLPAR) && acct->steal_time) { 423 account_steal_time(cputime_to_nsecs(acct->steal_time)); 424 acct->steal_time = 0; 425 } 426 427 if (acct->idle_time) 428 account_idle_time(cputime_to_nsecs(acct->idle_time)); 429 430 if (acct->stime) 431 account_system_index_time(tsk, cputime_to_nsecs(acct->stime), 432 CPUTIME_SYSTEM); 433 434 if (acct->hardirq_time) 435 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time), 436 CPUTIME_IRQ); 437 if (acct->softirq_time) 438 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time), 439 CPUTIME_SOFTIRQ); 440 441 vtime_flush_scaled(tsk, acct); 442 443 acct->utime = 0; 444 acct->gtime = 0; 445 acct->idle_time = 0; 446 acct->stime = 0; 447 acct->hardirq_time = 0; 448 acct->softirq_time = 0; 449 } 450 451 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 452 #define calc_cputime_factors() 453 #endif 454 455 void __delay(unsigned long loops) 456 { 457 unsigned long start; 458 459 spin_begin(); 460 if (tb_invalid) { 461 /* 462 * TB is in error state and isn't ticking anymore. 463 * HMI handler was unable to recover from TB error. 464 * Return immediately, so that kernel won't get stuck here. 465 */ 466 spin_cpu_relax(); 467 } else { 468 start = mftb(); 469 while (mftb() - start < loops) 470 spin_cpu_relax(); 471 } 472 spin_end(); 473 } 474 EXPORT_SYMBOL(__delay); 475 476 void udelay(unsigned long usecs) 477 { 478 __delay(tb_ticks_per_usec * usecs); 479 } 480 EXPORT_SYMBOL(udelay); 481 482 #ifdef CONFIG_SMP 483 unsigned long profile_pc(struct pt_regs *regs) 484 { 485 unsigned long pc = instruction_pointer(regs); 486 487 if (in_lock_functions(pc)) 488 return regs->link; 489 490 return pc; 491 } 492 EXPORT_SYMBOL(profile_pc); 493 #endif 494 495 #ifdef CONFIG_IRQ_WORK 496 497 /* 498 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 499 */ 500 #ifdef CONFIG_PPC64 501 static inline unsigned long test_irq_work_pending(void) 502 { 503 unsigned long x; 504 505 asm volatile("lbz %0,%1(13)" 506 : "=r" (x) 507 : "i" (offsetof(struct paca_struct, irq_work_pending))); 508 return x; 509 } 510 511 static inline void set_irq_work_pending_flag(void) 512 { 513 asm volatile("stb %0,%1(13)" : : 514 "r" (1), 515 "i" (offsetof(struct paca_struct, irq_work_pending))); 516 } 517 518 static inline void clear_irq_work_pending(void) 519 { 520 asm volatile("stb %0,%1(13)" : : 521 "r" (0), 522 "i" (offsetof(struct paca_struct, irq_work_pending))); 523 } 524 525 #else /* 32-bit */ 526 527 DEFINE_PER_CPU(u8, irq_work_pending); 528 529 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 530 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 531 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 532 533 #endif /* 32 vs 64 bit */ 534 535 void arch_irq_work_raise(void) 536 { 537 /* 538 * 64-bit code that uses irq soft-mask can just cause an immediate 539 * interrupt here that gets soft masked, if this is called under 540 * local_irq_disable(). It might be possible to prevent that happening 541 * by noticing interrupts are disabled and setting decrementer pending 542 * to be replayed when irqs are enabled. The problem there is that 543 * tracing can call irq_work_raise, including in code that does low 544 * level manipulations of irq soft-mask state (e.g., trace_hardirqs_on) 545 * which could get tangled up if we're messing with the same state 546 * here. 547 */ 548 preempt_disable(); 549 set_irq_work_pending_flag(); 550 set_dec(1); 551 preempt_enable(); 552 } 553 554 static void set_dec_or_work(u64 val) 555 { 556 set_dec(val); 557 /* We may have raced with new irq work */ 558 if (unlikely(test_irq_work_pending())) 559 set_dec(1); 560 } 561 562 #else /* CONFIG_IRQ_WORK */ 563 564 #define test_irq_work_pending() 0 565 #define clear_irq_work_pending() 566 567 static void set_dec_or_work(u64 val) 568 { 569 set_dec(val); 570 } 571 #endif /* CONFIG_IRQ_WORK */ 572 573 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE 574 void timer_rearm_host_dec(u64 now) 575 { 576 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 577 578 WARN_ON_ONCE(!arch_irqs_disabled()); 579 WARN_ON_ONCE(mfmsr() & MSR_EE); 580 581 if (now >= *next_tb) { 582 local_paca->irq_happened |= PACA_IRQ_DEC; 583 } else { 584 now = *next_tb - now; 585 if (now <= decrementer_max) 586 set_dec_or_work(now); 587 } 588 } 589 EXPORT_SYMBOL_GPL(timer_rearm_host_dec); 590 #endif 591 592 /* 593 * timer_interrupt - gets called when the decrementer overflows, 594 * with interrupts disabled. 595 */ 596 DEFINE_INTERRUPT_HANDLER_ASYNC(timer_interrupt) 597 { 598 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 599 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 600 struct pt_regs *old_regs; 601 u64 now; 602 603 /* 604 * Some implementations of hotplug will get timer interrupts while 605 * offline, just ignore these. 606 */ 607 if (unlikely(!cpu_online(smp_processor_id()))) { 608 set_dec(decrementer_max); 609 return; 610 } 611 612 /* Conditionally hard-enable interrupts. */ 613 if (should_hard_irq_enable()) { 614 /* 615 * Ensure a positive value is written to the decrementer, or 616 * else some CPUs will continue to take decrementer exceptions. 617 * When the PPC_WATCHDOG (decrementer based) is configured, 618 * keep this at most 31 bits, which is about 4 seconds on most 619 * systems, which gives the watchdog a chance of catching timer 620 * interrupt hard lockups. 621 */ 622 if (IS_ENABLED(CONFIG_PPC_WATCHDOG)) 623 set_dec(0x7fffffff); 624 else 625 set_dec(decrementer_max); 626 627 do_hard_irq_enable(); 628 } 629 630 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 631 if (atomic_read(&ppc_n_lost_interrupts) != 0) 632 __do_IRQ(regs); 633 #endif 634 635 old_regs = set_irq_regs(regs); 636 637 trace_timer_interrupt_entry(regs); 638 639 if (test_irq_work_pending()) { 640 clear_irq_work_pending(); 641 irq_work_run(); 642 } 643 644 now = get_tb(); 645 if (now >= *next_tb) { 646 *next_tb = ~(u64)0; 647 if (evt->event_handler) 648 evt->event_handler(evt); 649 __this_cpu_inc(irq_stat.timer_irqs_event); 650 } else { 651 now = *next_tb - now; 652 if (now > decrementer_max) 653 now = decrementer_max; 654 set_dec_or_work(now); 655 __this_cpu_inc(irq_stat.timer_irqs_others); 656 } 657 658 trace_timer_interrupt_exit(regs); 659 660 set_irq_regs(old_regs); 661 } 662 EXPORT_SYMBOL(timer_interrupt); 663 664 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 665 void timer_broadcast_interrupt(void) 666 { 667 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 668 669 *next_tb = ~(u64)0; 670 tick_receive_broadcast(); 671 __this_cpu_inc(irq_stat.broadcast_irqs_event); 672 } 673 #endif 674 675 #ifdef CONFIG_SUSPEND 676 /* Overrides the weak version in kernel/power/main.c */ 677 void arch_suspend_disable_irqs(void) 678 { 679 if (ppc_md.suspend_disable_irqs) 680 ppc_md.suspend_disable_irqs(); 681 682 /* Disable the decrementer, so that it doesn't interfere 683 * with suspending. 684 */ 685 686 set_dec(decrementer_max); 687 local_irq_disable(); 688 set_dec(decrementer_max); 689 } 690 691 /* Overrides the weak version in kernel/power/main.c */ 692 void arch_suspend_enable_irqs(void) 693 { 694 local_irq_enable(); 695 696 if (ppc_md.suspend_enable_irqs) 697 ppc_md.suspend_enable_irqs(); 698 } 699 #endif 700 701 unsigned long long tb_to_ns(unsigned long long ticks) 702 { 703 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 704 } 705 EXPORT_SYMBOL_GPL(tb_to_ns); 706 707 /* 708 * Scheduler clock - returns current time in nanosec units. 709 * 710 * Note: mulhdu(a, b) (multiply high double unsigned) returns 711 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 712 * are 64-bit unsigned numbers. 713 */ 714 notrace unsigned long long sched_clock(void) 715 { 716 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 717 } 718 719 720 #ifdef CONFIG_PPC_PSERIES 721 722 /* 723 * Running clock - attempts to give a view of time passing for a virtualised 724 * kernels. 725 * Uses the VTB register if available otherwise a next best guess. 726 */ 727 unsigned long long running_clock(void) 728 { 729 /* 730 * Don't read the VTB as a host since KVM does not switch in host 731 * timebase into the VTB when it takes a guest off the CPU, reading the 732 * VTB would result in reading 'last switched out' guest VTB. 733 * 734 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 735 * would be unsafe to rely only on the #ifdef above. 736 */ 737 if (firmware_has_feature(FW_FEATURE_LPAR) && 738 cpu_has_feature(CPU_FTR_ARCH_207S)) 739 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 740 741 /* 742 * This is a next best approximation without a VTB. 743 * On a host which is running bare metal there should never be any stolen 744 * time and on a host which doesn't do any virtualisation TB *should* equal 745 * VTB so it makes no difference anyway. 746 */ 747 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL]; 748 } 749 #endif 750 751 static int __init get_freq(char *name, int cells, unsigned long *val) 752 { 753 struct device_node *cpu; 754 const __be32 *fp; 755 int found = 0; 756 757 /* The cpu node should have timebase and clock frequency properties */ 758 cpu = of_find_node_by_type(NULL, "cpu"); 759 760 if (cpu) { 761 fp = of_get_property(cpu, name, NULL); 762 if (fp) { 763 found = 1; 764 *val = of_read_ulong(fp, cells); 765 } 766 767 of_node_put(cpu); 768 } 769 770 return found; 771 } 772 773 static void start_cpu_decrementer(void) 774 { 775 #ifdef CONFIG_BOOKE_OR_40x 776 unsigned int tcr; 777 778 /* Clear any pending timer interrupts */ 779 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 780 781 tcr = mfspr(SPRN_TCR); 782 /* 783 * The watchdog may have already been enabled by u-boot. So leave 784 * TRC[WP] (Watchdog Period) alone. 785 */ 786 tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */ 787 tcr |= TCR_DIE; /* Enable decrementer */ 788 mtspr(SPRN_TCR, tcr); 789 #endif 790 } 791 792 void __init generic_calibrate_decr(void) 793 { 794 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 795 796 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 797 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 798 799 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 800 "(not found)\n"); 801 } 802 803 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 804 805 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 806 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 807 808 printk(KERN_ERR "WARNING: Estimating processor frequency " 809 "(not found)\n"); 810 } 811 } 812 813 int update_persistent_clock64(struct timespec64 now) 814 { 815 struct rtc_time tm; 816 817 if (!ppc_md.set_rtc_time) 818 return -ENODEV; 819 820 rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm); 821 822 return ppc_md.set_rtc_time(&tm); 823 } 824 825 static void __read_persistent_clock(struct timespec64 *ts) 826 { 827 struct rtc_time tm; 828 static int first = 1; 829 830 ts->tv_nsec = 0; 831 /* XXX this is a litle fragile but will work okay in the short term */ 832 if (first) { 833 first = 0; 834 if (ppc_md.time_init) 835 timezone_offset = ppc_md.time_init(); 836 837 /* get_boot_time() isn't guaranteed to be safe to call late */ 838 if (ppc_md.get_boot_time) { 839 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 840 return; 841 } 842 } 843 if (!ppc_md.get_rtc_time) { 844 ts->tv_sec = 0; 845 return; 846 } 847 ppc_md.get_rtc_time(&tm); 848 849 ts->tv_sec = rtc_tm_to_time64(&tm); 850 } 851 852 void read_persistent_clock64(struct timespec64 *ts) 853 { 854 __read_persistent_clock(ts); 855 856 /* Sanitize it in case real time clock is set below EPOCH */ 857 if (ts->tv_sec < 0) { 858 ts->tv_sec = 0; 859 ts->tv_nsec = 0; 860 } 861 862 } 863 864 /* clocksource code */ 865 static notrace u64 timebase_read(struct clocksource *cs) 866 { 867 return (u64)get_tb(); 868 } 869 870 static void __init clocksource_init(void) 871 { 872 struct clocksource *clock = &clocksource_timebase; 873 874 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 875 printk(KERN_ERR "clocksource: %s is already registered\n", 876 clock->name); 877 return; 878 } 879 880 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 881 clock->name, clock->mult, clock->shift); 882 } 883 884 static int decrementer_set_next_event(unsigned long evt, 885 struct clock_event_device *dev) 886 { 887 __this_cpu_write(decrementers_next_tb, get_tb() + evt); 888 set_dec_or_work(evt); 889 890 return 0; 891 } 892 893 static int decrementer_shutdown(struct clock_event_device *dev) 894 { 895 decrementer_set_next_event(decrementer_max, dev); 896 return 0; 897 } 898 899 static void register_decrementer_clockevent(int cpu) 900 { 901 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 902 903 *dec = decrementer_clockevent; 904 dec->cpumask = cpumask_of(cpu); 905 906 clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max); 907 908 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 909 dec->name, dec->mult, dec->shift, cpu); 910 911 /* Set values for KVM, see kvm_emulate_dec() */ 912 decrementer_clockevent.mult = dec->mult; 913 decrementer_clockevent.shift = dec->shift; 914 } 915 916 static void enable_large_decrementer(void) 917 { 918 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 919 return; 920 921 if (decrementer_max <= DECREMENTER_DEFAULT_MAX) 922 return; 923 924 /* 925 * If we're running as the hypervisor we need to enable the LD manually 926 * otherwise firmware should have done it for us. 927 */ 928 if (cpu_has_feature(CPU_FTR_HVMODE)) 929 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); 930 } 931 932 static void __init set_decrementer_max(void) 933 { 934 struct device_node *cpu; 935 u32 bits = 32; 936 937 /* Prior to ISAv3 the decrementer is always 32 bit */ 938 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 939 return; 940 941 cpu = of_find_node_by_type(NULL, "cpu"); 942 943 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { 944 if (bits > 64 || bits < 32) { 945 pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); 946 bits = 32; 947 } 948 949 /* calculate the signed maximum given this many bits */ 950 decrementer_max = (1ul << (bits - 1)) - 1; 951 } 952 953 of_node_put(cpu); 954 955 pr_info("time_init: %u bit decrementer (max: %llx)\n", 956 bits, decrementer_max); 957 } 958 959 static void __init init_decrementer_clockevent(void) 960 { 961 register_decrementer_clockevent(smp_processor_id()); 962 } 963 964 void secondary_cpu_time_init(void) 965 { 966 /* Enable and test the large decrementer for this cpu */ 967 enable_large_decrementer(); 968 969 /* Start the decrementer on CPUs that have manual control 970 * such as BookE 971 */ 972 start_cpu_decrementer(); 973 974 /* FIME: Should make unrelatred change to move snapshot_timebase 975 * call here ! */ 976 register_decrementer_clockevent(smp_processor_id()); 977 } 978 979 /* This function is only called on the boot processor */ 980 void __init time_init(void) 981 { 982 struct div_result res; 983 u64 scale; 984 unsigned shift; 985 986 /* Normal PowerPC with timebase register */ 987 ppc_md.calibrate_decr(); 988 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 989 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 990 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 991 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 992 993 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 994 tb_ticks_per_sec = ppc_tb_freq; 995 tb_ticks_per_usec = ppc_tb_freq / 1000000; 996 calc_cputime_factors(); 997 998 /* 999 * Compute scale factor for sched_clock. 1000 * The calibrate_decr() function has set tb_ticks_per_sec, 1001 * which is the timebase frequency. 1002 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1003 * the 128-bit result as a 64.64 fixed-point number. 1004 * We then shift that number right until it is less than 1.0, 1005 * giving us the scale factor and shift count to use in 1006 * sched_clock(). 1007 */ 1008 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1009 scale = res.result_low; 1010 for (shift = 0; res.result_high != 0; ++shift) { 1011 scale = (scale >> 1) | (res.result_high << 63); 1012 res.result_high >>= 1; 1013 } 1014 tb_to_ns_scale = scale; 1015 tb_to_ns_shift = shift; 1016 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1017 boot_tb = get_tb(); 1018 1019 /* If platform provided a timezone (pmac), we correct the time */ 1020 if (timezone_offset) { 1021 sys_tz.tz_minuteswest = -timezone_offset / 60; 1022 sys_tz.tz_dsttime = 0; 1023 } 1024 1025 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1026 1027 /* initialise and enable the large decrementer (if we have one) */ 1028 set_decrementer_max(); 1029 enable_large_decrementer(); 1030 1031 /* Start the decrementer on CPUs that have manual control 1032 * such as BookE 1033 */ 1034 start_cpu_decrementer(); 1035 1036 /* Register the clocksource */ 1037 clocksource_init(); 1038 1039 init_decrementer_clockevent(); 1040 tick_setup_hrtimer_broadcast(); 1041 1042 of_clk_init(NULL); 1043 enable_sched_clock_irqtime(); 1044 } 1045 1046 /* 1047 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1048 * result. 1049 */ 1050 void div128_by_32(u64 dividend_high, u64 dividend_low, 1051 unsigned divisor, struct div_result *dr) 1052 { 1053 unsigned long a, b, c, d; 1054 unsigned long w, x, y, z; 1055 u64 ra, rb, rc; 1056 1057 a = dividend_high >> 32; 1058 b = dividend_high & 0xffffffff; 1059 c = dividend_low >> 32; 1060 d = dividend_low & 0xffffffff; 1061 1062 w = a / divisor; 1063 ra = ((u64)(a - (w * divisor)) << 32) + b; 1064 1065 rb = ((u64) do_div(ra, divisor) << 32) + c; 1066 x = ra; 1067 1068 rc = ((u64) do_div(rb, divisor) << 32) + d; 1069 y = rb; 1070 1071 do_div(rc, divisor); 1072 z = rc; 1073 1074 dr->result_high = ((u64)w << 32) + x; 1075 dr->result_low = ((u64)y << 32) + z; 1076 1077 } 1078 1079 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1080 void calibrate_delay(void) 1081 { 1082 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1083 * as the number of __delay(1) in a jiffy, so make it so 1084 */ 1085 loops_per_jiffy = tb_ticks_per_jiffy; 1086 } 1087 1088 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 1089 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 1090 { 1091 ppc_md.get_rtc_time(tm); 1092 return 0; 1093 } 1094 1095 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 1096 { 1097 if (!ppc_md.set_rtc_time) 1098 return -EOPNOTSUPP; 1099 1100 if (ppc_md.set_rtc_time(tm) < 0) 1101 return -EOPNOTSUPP; 1102 1103 return 0; 1104 } 1105 1106 static const struct rtc_class_ops rtc_generic_ops = { 1107 .read_time = rtc_generic_get_time, 1108 .set_time = rtc_generic_set_time, 1109 }; 1110 1111 static int __init rtc_init(void) 1112 { 1113 struct platform_device *pdev; 1114 1115 if (!ppc_md.get_rtc_time) 1116 return -ENODEV; 1117 1118 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 1119 &rtc_generic_ops, 1120 sizeof(rtc_generic_ops)); 1121 1122 return PTR_ERR_OR_ZERO(pdev); 1123 } 1124 1125 device_initcall(rtc_init); 1126 #endif 1127