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/mce.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 /* 111 * This always puts next_tb beyond now, so the clock event will never fire 112 * with the usual comparison, no need for a separate test for stopped. 113 */ 114 #define DEC_CLOCKEVENT_STOPPED ~0ULL 115 DEFINE_PER_CPU(u64, decrementers_next_tb) = DEC_CLOCKEVENT_STOPPED; 116 EXPORT_SYMBOL_GPL(decrementers_next_tb); 117 static DEFINE_PER_CPU(struct clock_event_device, decrementers); 118 119 #define XSEC_PER_SEC (1024*1024) 120 121 #ifdef CONFIG_PPC64 122 #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) 123 #else 124 /* compute ((xsec << 12) * max) >> 32 */ 125 #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) 126 #endif 127 128 unsigned long tb_ticks_per_jiffy; 129 unsigned long tb_ticks_per_usec = 100; /* sane default */ 130 EXPORT_SYMBOL(tb_ticks_per_usec); 131 unsigned long tb_ticks_per_sec; 132 EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ 133 134 DEFINE_SPINLOCK(rtc_lock); 135 EXPORT_SYMBOL_GPL(rtc_lock); 136 137 static u64 tb_to_ns_scale __read_mostly; 138 static unsigned tb_to_ns_shift __read_mostly; 139 static u64 boot_tb __read_mostly; 140 141 extern struct timezone sys_tz; 142 static long timezone_offset; 143 144 unsigned long ppc_proc_freq; 145 EXPORT_SYMBOL_GPL(ppc_proc_freq); 146 unsigned long ppc_tb_freq; 147 EXPORT_SYMBOL_GPL(ppc_tb_freq); 148 149 bool tb_invalid; 150 151 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE 152 /* 153 * Factor for converting from cputime_t (timebase ticks) to 154 * microseconds. This is stored as 0.64 fixed-point binary fraction. 155 */ 156 u64 __cputime_usec_factor; 157 EXPORT_SYMBOL(__cputime_usec_factor); 158 159 #ifdef CONFIG_PPC_SPLPAR 160 void (*dtl_consumer)(struct dtl_entry *, u64); 161 #endif 162 163 static void calc_cputime_factors(void) 164 { 165 struct div_result res; 166 167 div128_by_32(1000000, 0, tb_ticks_per_sec, &res); 168 __cputime_usec_factor = res.result_low; 169 } 170 171 /* 172 * Read the SPURR on systems that have it, otherwise the PURR, 173 * or if that doesn't exist return the timebase value passed in. 174 */ 175 static inline unsigned long read_spurr(unsigned long tb) 176 { 177 if (cpu_has_feature(CPU_FTR_SPURR)) 178 return mfspr(SPRN_SPURR); 179 if (cpu_has_feature(CPU_FTR_PURR)) 180 return mfspr(SPRN_PURR); 181 return tb; 182 } 183 184 #ifdef CONFIG_PPC_SPLPAR 185 186 #include <asm/dtl.h> 187 188 /* 189 * Scan the dispatch trace log and count up the stolen time. 190 * Should be called with interrupts disabled. 191 */ 192 static u64 scan_dispatch_log(u64 stop_tb) 193 { 194 u64 i = local_paca->dtl_ridx; 195 struct dtl_entry *dtl = local_paca->dtl_curr; 196 struct dtl_entry *dtl_end = local_paca->dispatch_log_end; 197 struct lppaca *vpa = local_paca->lppaca_ptr; 198 u64 tb_delta; 199 u64 stolen = 0; 200 u64 dtb; 201 202 if (!dtl) 203 return 0; 204 205 if (i == be64_to_cpu(vpa->dtl_idx)) 206 return 0; 207 while (i < be64_to_cpu(vpa->dtl_idx)) { 208 dtb = be64_to_cpu(dtl->timebase); 209 tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + 210 be32_to_cpu(dtl->ready_to_enqueue_time); 211 barrier(); 212 if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { 213 /* buffer has overflowed */ 214 i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; 215 dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); 216 continue; 217 } 218 if (dtb > stop_tb) 219 break; 220 if (dtl_consumer) 221 dtl_consumer(dtl, i); 222 stolen += tb_delta; 223 ++i; 224 ++dtl; 225 if (dtl == dtl_end) 226 dtl = local_paca->dispatch_log; 227 } 228 local_paca->dtl_ridx = i; 229 local_paca->dtl_curr = dtl; 230 return stolen; 231 } 232 233 /* 234 * Accumulate stolen time by scanning the dispatch trace log. 235 * Called on entry from user mode. 236 */ 237 void notrace accumulate_stolen_time(void) 238 { 239 u64 sst, ust; 240 struct cpu_accounting_data *acct = &local_paca->accounting; 241 242 sst = scan_dispatch_log(acct->starttime_user); 243 ust = scan_dispatch_log(acct->starttime); 244 acct->stime -= sst; 245 acct->utime -= ust; 246 acct->steal_time += ust + sst; 247 } 248 249 static inline u64 calculate_stolen_time(u64 stop_tb) 250 { 251 if (!firmware_has_feature(FW_FEATURE_SPLPAR)) 252 return 0; 253 254 if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) 255 return scan_dispatch_log(stop_tb); 256 257 return 0; 258 } 259 260 #else /* CONFIG_PPC_SPLPAR */ 261 static inline u64 calculate_stolen_time(u64 stop_tb) 262 { 263 return 0; 264 } 265 266 #endif /* CONFIG_PPC_SPLPAR */ 267 268 /* 269 * Account time for a transition between system, hard irq 270 * or soft irq state. 271 */ 272 static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct, 273 unsigned long now, unsigned long stime) 274 { 275 unsigned long stime_scaled = 0; 276 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 277 unsigned long nowscaled, deltascaled; 278 unsigned long utime, utime_scaled; 279 280 nowscaled = read_spurr(now); 281 deltascaled = nowscaled - acct->startspurr; 282 acct->startspurr = nowscaled; 283 utime = acct->utime - acct->utime_sspurr; 284 acct->utime_sspurr = acct->utime; 285 286 /* 287 * Because we don't read the SPURR on every kernel entry/exit, 288 * deltascaled includes both user and system SPURR ticks. 289 * Apportion these ticks to system SPURR ticks and user 290 * SPURR ticks in the same ratio as the system time (delta) 291 * and user time (udelta) values obtained from the timebase 292 * over the same interval. The system ticks get accounted here; 293 * the user ticks get saved up in paca->user_time_scaled to be 294 * used by account_process_tick. 295 */ 296 stime_scaled = stime; 297 utime_scaled = utime; 298 if (deltascaled != stime + utime) { 299 if (utime) { 300 stime_scaled = deltascaled * stime / (stime + utime); 301 utime_scaled = deltascaled - stime_scaled; 302 } else { 303 stime_scaled = deltascaled; 304 } 305 } 306 acct->utime_scaled += utime_scaled; 307 #endif 308 309 return stime_scaled; 310 } 311 312 static unsigned long vtime_delta(struct cpu_accounting_data *acct, 313 unsigned long *stime_scaled, 314 unsigned long *steal_time) 315 { 316 unsigned long now, stime; 317 318 WARN_ON_ONCE(!irqs_disabled()); 319 320 now = mftb(); 321 stime = now - acct->starttime; 322 acct->starttime = now; 323 324 *stime_scaled = vtime_delta_scaled(acct, now, stime); 325 326 *steal_time = calculate_stolen_time(now); 327 328 return stime; 329 } 330 331 static void vtime_delta_kernel(struct cpu_accounting_data *acct, 332 unsigned long *stime, unsigned long *stime_scaled) 333 { 334 unsigned long steal_time; 335 336 *stime = vtime_delta(acct, stime_scaled, &steal_time); 337 *stime -= min(*stime, steal_time); 338 acct->steal_time += steal_time; 339 } 340 341 void vtime_account_kernel(struct task_struct *tsk) 342 { 343 struct cpu_accounting_data *acct = get_accounting(tsk); 344 unsigned long stime, stime_scaled; 345 346 vtime_delta_kernel(acct, &stime, &stime_scaled); 347 348 if (tsk->flags & PF_VCPU) { 349 acct->gtime += stime; 350 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 351 acct->utime_scaled += stime_scaled; 352 #endif 353 } else { 354 acct->stime += stime; 355 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 356 acct->stime_scaled += stime_scaled; 357 #endif 358 } 359 } 360 EXPORT_SYMBOL_GPL(vtime_account_kernel); 361 362 void vtime_account_idle(struct task_struct *tsk) 363 { 364 unsigned long stime, stime_scaled, steal_time; 365 struct cpu_accounting_data *acct = get_accounting(tsk); 366 367 stime = vtime_delta(acct, &stime_scaled, &steal_time); 368 acct->idle_time += stime + steal_time; 369 } 370 371 static void vtime_account_irq_field(struct cpu_accounting_data *acct, 372 unsigned long *field) 373 { 374 unsigned long stime, stime_scaled; 375 376 vtime_delta_kernel(acct, &stime, &stime_scaled); 377 *field += stime; 378 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 379 acct->stime_scaled += stime_scaled; 380 #endif 381 } 382 383 void vtime_account_softirq(struct task_struct *tsk) 384 { 385 struct cpu_accounting_data *acct = get_accounting(tsk); 386 vtime_account_irq_field(acct, &acct->softirq_time); 387 } 388 389 void vtime_account_hardirq(struct task_struct *tsk) 390 { 391 struct cpu_accounting_data *acct = get_accounting(tsk); 392 vtime_account_irq_field(acct, &acct->hardirq_time); 393 } 394 395 static void vtime_flush_scaled(struct task_struct *tsk, 396 struct cpu_accounting_data *acct) 397 { 398 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME 399 if (acct->utime_scaled) 400 tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled); 401 if (acct->stime_scaled) 402 tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled); 403 404 acct->utime_scaled = 0; 405 acct->utime_sspurr = 0; 406 acct->stime_scaled = 0; 407 #endif 408 } 409 410 /* 411 * Account the whole cputime accumulated in the paca 412 * Must be called with interrupts disabled. 413 * Assumes that vtime_account_kernel/idle() has been called 414 * recently (i.e. since the last entry from usermode) so that 415 * get_paca()->user_time_scaled is up to date. 416 */ 417 void vtime_flush(struct task_struct *tsk) 418 { 419 struct cpu_accounting_data *acct = get_accounting(tsk); 420 421 if (acct->utime) 422 account_user_time(tsk, cputime_to_nsecs(acct->utime)); 423 424 if (acct->gtime) 425 account_guest_time(tsk, cputime_to_nsecs(acct->gtime)); 426 427 if (IS_ENABLED(CONFIG_PPC_SPLPAR) && acct->steal_time) { 428 account_steal_time(cputime_to_nsecs(acct->steal_time)); 429 acct->steal_time = 0; 430 } 431 432 if (acct->idle_time) 433 account_idle_time(cputime_to_nsecs(acct->idle_time)); 434 435 if (acct->stime) 436 account_system_index_time(tsk, cputime_to_nsecs(acct->stime), 437 CPUTIME_SYSTEM); 438 439 if (acct->hardirq_time) 440 account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time), 441 CPUTIME_IRQ); 442 if (acct->softirq_time) 443 account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time), 444 CPUTIME_SOFTIRQ); 445 446 vtime_flush_scaled(tsk, acct); 447 448 acct->utime = 0; 449 acct->gtime = 0; 450 acct->idle_time = 0; 451 acct->stime = 0; 452 acct->hardirq_time = 0; 453 acct->softirq_time = 0; 454 } 455 456 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ 457 #define calc_cputime_factors() 458 #endif 459 460 void __delay(unsigned long loops) 461 { 462 unsigned long start; 463 464 spin_begin(); 465 if (tb_invalid) { 466 /* 467 * TB is in error state and isn't ticking anymore. 468 * HMI handler was unable to recover from TB error. 469 * Return immediately, so that kernel won't get stuck here. 470 */ 471 spin_cpu_relax(); 472 } else { 473 start = mftb(); 474 while (mftb() - start < loops) 475 spin_cpu_relax(); 476 } 477 spin_end(); 478 } 479 EXPORT_SYMBOL(__delay); 480 481 void udelay(unsigned long usecs) 482 { 483 __delay(tb_ticks_per_usec * usecs); 484 } 485 EXPORT_SYMBOL(udelay); 486 487 #ifdef CONFIG_SMP 488 unsigned long profile_pc(struct pt_regs *regs) 489 { 490 unsigned long pc = instruction_pointer(regs); 491 492 if (in_lock_functions(pc)) 493 return regs->link; 494 495 return pc; 496 } 497 EXPORT_SYMBOL(profile_pc); 498 #endif 499 500 #ifdef CONFIG_IRQ_WORK 501 502 /* 503 * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... 504 */ 505 #ifdef CONFIG_PPC64 506 static inline unsigned long test_irq_work_pending(void) 507 { 508 unsigned long x; 509 510 asm volatile("lbz %0,%1(13)" 511 : "=r" (x) 512 : "i" (offsetof(struct paca_struct, irq_work_pending))); 513 return x; 514 } 515 516 static inline void set_irq_work_pending_flag(void) 517 { 518 asm volatile("stb %0,%1(13)" : : 519 "r" (1), 520 "i" (offsetof(struct paca_struct, irq_work_pending))); 521 } 522 523 static inline void clear_irq_work_pending(void) 524 { 525 asm volatile("stb %0,%1(13)" : : 526 "r" (0), 527 "i" (offsetof(struct paca_struct, irq_work_pending))); 528 } 529 530 #else /* 32-bit */ 531 532 DEFINE_PER_CPU(u8, irq_work_pending); 533 534 #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) 535 #define test_irq_work_pending() __this_cpu_read(irq_work_pending) 536 #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) 537 538 #endif /* 32 vs 64 bit */ 539 540 void arch_irq_work_raise(void) 541 { 542 /* 543 * 64-bit code that uses irq soft-mask can just cause an immediate 544 * interrupt here that gets soft masked, if this is called under 545 * local_irq_disable(). It might be possible to prevent that happening 546 * by noticing interrupts are disabled and setting decrementer pending 547 * to be replayed when irqs are enabled. The problem there is that 548 * tracing can call irq_work_raise, including in code that does low 549 * level manipulations of irq soft-mask state (e.g., trace_hardirqs_on) 550 * which could get tangled up if we're messing with the same state 551 * here. 552 */ 553 preempt_disable(); 554 set_irq_work_pending_flag(); 555 set_dec(1); 556 preempt_enable(); 557 } 558 559 static void set_dec_or_work(u64 val) 560 { 561 set_dec(val); 562 /* We may have raced with new irq work */ 563 if (unlikely(test_irq_work_pending())) 564 set_dec(1); 565 } 566 567 #else /* CONFIG_IRQ_WORK */ 568 569 #define test_irq_work_pending() 0 570 #define clear_irq_work_pending() 571 572 static void set_dec_or_work(u64 val) 573 { 574 set_dec(val); 575 } 576 #endif /* CONFIG_IRQ_WORK */ 577 578 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE 579 void timer_rearm_host_dec(u64 now) 580 { 581 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 582 583 WARN_ON_ONCE(!arch_irqs_disabled()); 584 WARN_ON_ONCE(mfmsr() & MSR_EE); 585 586 if (now >= *next_tb) { 587 local_paca->irq_happened |= PACA_IRQ_DEC; 588 } else { 589 now = *next_tb - now; 590 if (now > decrementer_max) 591 now = decrementer_max; 592 set_dec_or_work(now); 593 } 594 } 595 EXPORT_SYMBOL_GPL(timer_rearm_host_dec); 596 #endif 597 598 /* 599 * timer_interrupt - gets called when the decrementer overflows, 600 * with interrupts disabled. 601 */ 602 DEFINE_INTERRUPT_HANDLER_ASYNC(timer_interrupt) 603 { 604 struct clock_event_device *evt = this_cpu_ptr(&decrementers); 605 u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); 606 struct pt_regs *old_regs; 607 u64 now; 608 609 /* 610 * Some implementations of hotplug will get timer interrupts while 611 * offline, just ignore these. 612 */ 613 if (unlikely(!cpu_online(smp_processor_id()))) { 614 set_dec(decrementer_max); 615 return; 616 } 617 618 /* Conditionally hard-enable interrupts. */ 619 if (should_hard_irq_enable()) { 620 /* 621 * Ensure a positive value is written to the decrementer, or 622 * else some CPUs will continue to take decrementer exceptions. 623 * When the PPC_WATCHDOG (decrementer based) is configured, 624 * keep this at most 31 bits, which is about 4 seconds on most 625 * systems, which gives the watchdog a chance of catching timer 626 * interrupt hard lockups. 627 */ 628 if (IS_ENABLED(CONFIG_PPC_WATCHDOG)) 629 set_dec(0x7fffffff); 630 else 631 set_dec(decrementer_max); 632 633 do_hard_irq_enable(); 634 } 635 636 #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) 637 if (atomic_read(&ppc_n_lost_interrupts) != 0) 638 __do_IRQ(regs); 639 #endif 640 641 old_regs = set_irq_regs(regs); 642 643 trace_timer_interrupt_entry(regs); 644 645 if (test_irq_work_pending()) { 646 clear_irq_work_pending(); 647 mce_run_irq_context_handlers(); 648 irq_work_run(); 649 } 650 651 now = get_tb(); 652 if (now >= *next_tb) { 653 evt->event_handler(evt); 654 __this_cpu_inc(irq_stat.timer_irqs_event); 655 } else { 656 now = *next_tb - now; 657 if (now > decrementer_max) 658 now = decrementer_max; 659 set_dec_or_work(now); 660 __this_cpu_inc(irq_stat.timer_irqs_others); 661 } 662 663 trace_timer_interrupt_exit(regs); 664 665 set_irq_regs(old_regs); 666 } 667 EXPORT_SYMBOL(timer_interrupt); 668 669 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 670 void timer_broadcast_interrupt(void) 671 { 672 tick_receive_broadcast(); 673 __this_cpu_inc(irq_stat.broadcast_irqs_event); 674 } 675 #endif 676 677 #ifdef CONFIG_SUSPEND 678 /* Overrides the weak version in kernel/power/main.c */ 679 void arch_suspend_disable_irqs(void) 680 { 681 if (ppc_md.suspend_disable_irqs) 682 ppc_md.suspend_disable_irqs(); 683 684 /* Disable the decrementer, so that it doesn't interfere 685 * with suspending. 686 */ 687 688 set_dec(decrementer_max); 689 local_irq_disable(); 690 set_dec(decrementer_max); 691 } 692 693 /* Overrides the weak version in kernel/power/main.c */ 694 void arch_suspend_enable_irqs(void) 695 { 696 local_irq_enable(); 697 698 if (ppc_md.suspend_enable_irqs) 699 ppc_md.suspend_enable_irqs(); 700 } 701 #endif 702 703 unsigned long long tb_to_ns(unsigned long long ticks) 704 { 705 return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; 706 } 707 EXPORT_SYMBOL_GPL(tb_to_ns); 708 709 /* 710 * Scheduler clock - returns current time in nanosec units. 711 * 712 * Note: mulhdu(a, b) (multiply high double unsigned) returns 713 * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b 714 * are 64-bit unsigned numbers. 715 */ 716 notrace unsigned long long sched_clock(void) 717 { 718 return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 719 } 720 721 722 #ifdef CONFIG_PPC_PSERIES 723 724 /* 725 * Running clock - attempts to give a view of time passing for a virtualised 726 * kernels. 727 * Uses the VTB register if available otherwise a next best guess. 728 */ 729 unsigned long long running_clock(void) 730 { 731 /* 732 * Don't read the VTB as a host since KVM does not switch in host 733 * timebase into the VTB when it takes a guest off the CPU, reading the 734 * VTB would result in reading 'last switched out' guest VTB. 735 * 736 * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it 737 * would be unsafe to rely only on the #ifdef above. 738 */ 739 if (firmware_has_feature(FW_FEATURE_LPAR) && 740 cpu_has_feature(CPU_FTR_ARCH_207S)) 741 return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; 742 743 /* 744 * This is a next best approximation without a VTB. 745 * On a host which is running bare metal there should never be any stolen 746 * time and on a host which doesn't do any virtualisation TB *should* equal 747 * VTB so it makes no difference anyway. 748 */ 749 return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL]; 750 } 751 #endif 752 753 static int __init get_freq(char *name, int cells, unsigned long *val) 754 { 755 struct device_node *cpu; 756 const __be32 *fp; 757 int found = 0; 758 759 /* The cpu node should have timebase and clock frequency properties */ 760 cpu = of_find_node_by_type(NULL, "cpu"); 761 762 if (cpu) { 763 fp = of_get_property(cpu, name, NULL); 764 if (fp) { 765 found = 1; 766 *val = of_read_ulong(fp, cells); 767 } 768 769 of_node_put(cpu); 770 } 771 772 return found; 773 } 774 775 static void start_cpu_decrementer(void) 776 { 777 #ifdef CONFIG_BOOKE_OR_40x 778 unsigned int tcr; 779 780 /* Clear any pending timer interrupts */ 781 mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); 782 783 tcr = mfspr(SPRN_TCR); 784 /* 785 * The watchdog may have already been enabled by u-boot. So leave 786 * TRC[WP] (Watchdog Period) alone. 787 */ 788 tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */ 789 tcr |= TCR_DIE; /* Enable decrementer */ 790 mtspr(SPRN_TCR, tcr); 791 #endif 792 } 793 794 void __init generic_calibrate_decr(void) 795 { 796 ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ 797 798 if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && 799 !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { 800 801 printk(KERN_ERR "WARNING: Estimating decrementer frequency " 802 "(not found)\n"); 803 } 804 805 ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ 806 807 if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && 808 !get_freq("clock-frequency", 1, &ppc_proc_freq)) { 809 810 printk(KERN_ERR "WARNING: Estimating processor frequency " 811 "(not found)\n"); 812 } 813 } 814 815 int update_persistent_clock64(struct timespec64 now) 816 { 817 struct rtc_time tm; 818 819 if (!ppc_md.set_rtc_time) 820 return -ENODEV; 821 822 rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm); 823 824 return ppc_md.set_rtc_time(&tm); 825 } 826 827 static void __read_persistent_clock(struct timespec64 *ts) 828 { 829 struct rtc_time tm; 830 static int first = 1; 831 832 ts->tv_nsec = 0; 833 /* XXX this is a litle fragile but will work okay in the short term */ 834 if (first) { 835 first = 0; 836 if (ppc_md.time_init) 837 timezone_offset = ppc_md.time_init(); 838 839 /* get_boot_time() isn't guaranteed to be safe to call late */ 840 if (ppc_md.get_boot_time) { 841 ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; 842 return; 843 } 844 } 845 if (!ppc_md.get_rtc_time) { 846 ts->tv_sec = 0; 847 return; 848 } 849 ppc_md.get_rtc_time(&tm); 850 851 ts->tv_sec = rtc_tm_to_time64(&tm); 852 } 853 854 void read_persistent_clock64(struct timespec64 *ts) 855 { 856 __read_persistent_clock(ts); 857 858 /* Sanitize it in case real time clock is set below EPOCH */ 859 if (ts->tv_sec < 0) { 860 ts->tv_sec = 0; 861 ts->tv_nsec = 0; 862 } 863 864 } 865 866 /* clocksource code */ 867 static notrace u64 timebase_read(struct clocksource *cs) 868 { 869 return (u64)get_tb(); 870 } 871 872 static void __init clocksource_init(void) 873 { 874 struct clocksource *clock = &clocksource_timebase; 875 876 if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 877 printk(KERN_ERR "clocksource: %s is already registered\n", 878 clock->name); 879 return; 880 } 881 882 printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", 883 clock->name, clock->mult, clock->shift); 884 } 885 886 static int decrementer_set_next_event(unsigned long evt, 887 struct clock_event_device *dev) 888 { 889 __this_cpu_write(decrementers_next_tb, get_tb() + evt); 890 set_dec_or_work(evt); 891 892 return 0; 893 } 894 895 static int decrementer_shutdown(struct clock_event_device *dev) 896 { 897 __this_cpu_write(decrementers_next_tb, DEC_CLOCKEVENT_STOPPED); 898 set_dec_or_work(decrementer_max); 899 900 return 0; 901 } 902 903 static void register_decrementer_clockevent(int cpu) 904 { 905 struct clock_event_device *dec = &per_cpu(decrementers, cpu); 906 907 *dec = decrementer_clockevent; 908 dec->cpumask = cpumask_of(cpu); 909 910 clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max); 911 912 printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", 913 dec->name, dec->mult, dec->shift, cpu); 914 915 /* Set values for KVM, see kvm_emulate_dec() */ 916 decrementer_clockevent.mult = dec->mult; 917 decrementer_clockevent.shift = dec->shift; 918 } 919 920 static void enable_large_decrementer(void) 921 { 922 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 923 return; 924 925 if (decrementer_max <= DECREMENTER_DEFAULT_MAX) 926 return; 927 928 /* 929 * If we're running as the hypervisor we need to enable the LD manually 930 * otherwise firmware should have done it for us. 931 */ 932 if (cpu_has_feature(CPU_FTR_HVMODE)) 933 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); 934 } 935 936 static void __init set_decrementer_max(void) 937 { 938 struct device_node *cpu; 939 u32 bits = 32; 940 941 /* Prior to ISAv3 the decrementer is always 32 bit */ 942 if (!cpu_has_feature(CPU_FTR_ARCH_300)) 943 return; 944 945 cpu = of_find_node_by_type(NULL, "cpu"); 946 947 if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { 948 if (bits > 64 || bits < 32) { 949 pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); 950 bits = 32; 951 } 952 953 /* calculate the signed maximum given this many bits */ 954 decrementer_max = (1ul << (bits - 1)) - 1; 955 } 956 957 of_node_put(cpu); 958 959 pr_info("time_init: %u bit decrementer (max: %llx)\n", 960 bits, decrementer_max); 961 } 962 963 static void __init init_decrementer_clockevent(void) 964 { 965 register_decrementer_clockevent(smp_processor_id()); 966 } 967 968 void secondary_cpu_time_init(void) 969 { 970 /* Enable and test the large decrementer for this cpu */ 971 enable_large_decrementer(); 972 973 /* Start the decrementer on CPUs that have manual control 974 * such as BookE 975 */ 976 start_cpu_decrementer(); 977 978 /* FIME: Should make unrelatred change to move snapshot_timebase 979 * call here ! */ 980 register_decrementer_clockevent(smp_processor_id()); 981 } 982 983 /* This function is only called on the boot processor */ 984 void __init time_init(void) 985 { 986 struct div_result res; 987 u64 scale; 988 unsigned shift; 989 990 /* Normal PowerPC with timebase register */ 991 ppc_md.calibrate_decr(); 992 printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", 993 ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); 994 printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", 995 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 996 997 tb_ticks_per_jiffy = ppc_tb_freq / HZ; 998 tb_ticks_per_sec = ppc_tb_freq; 999 tb_ticks_per_usec = ppc_tb_freq / 1000000; 1000 calc_cputime_factors(); 1001 1002 /* 1003 * Compute scale factor for sched_clock. 1004 * The calibrate_decr() function has set tb_ticks_per_sec, 1005 * which is the timebase frequency. 1006 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret 1007 * the 128-bit result as a 64.64 fixed-point number. 1008 * We then shift that number right until it is less than 1.0, 1009 * giving us the scale factor and shift count to use in 1010 * sched_clock(). 1011 */ 1012 div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); 1013 scale = res.result_low; 1014 for (shift = 0; res.result_high != 0; ++shift) { 1015 scale = (scale >> 1) | (res.result_high << 63); 1016 res.result_high >>= 1; 1017 } 1018 tb_to_ns_scale = scale; 1019 tb_to_ns_shift = shift; 1020 /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ 1021 boot_tb = get_tb(); 1022 1023 /* If platform provided a timezone (pmac), we correct the time */ 1024 if (timezone_offset) { 1025 sys_tz.tz_minuteswest = -timezone_offset / 60; 1026 sys_tz.tz_dsttime = 0; 1027 } 1028 1029 vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; 1030 1031 /* initialise and enable the large decrementer (if we have one) */ 1032 set_decrementer_max(); 1033 enable_large_decrementer(); 1034 1035 /* Start the decrementer on CPUs that have manual control 1036 * such as BookE 1037 */ 1038 start_cpu_decrementer(); 1039 1040 /* Register the clocksource */ 1041 clocksource_init(); 1042 1043 init_decrementer_clockevent(); 1044 tick_setup_hrtimer_broadcast(); 1045 1046 of_clk_init(NULL); 1047 enable_sched_clock_irqtime(); 1048 } 1049 1050 /* 1051 * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit 1052 * result. 1053 */ 1054 void div128_by_32(u64 dividend_high, u64 dividend_low, 1055 unsigned divisor, struct div_result *dr) 1056 { 1057 unsigned long a, b, c, d; 1058 unsigned long w, x, y, z; 1059 u64 ra, rb, rc; 1060 1061 a = dividend_high >> 32; 1062 b = dividend_high & 0xffffffff; 1063 c = dividend_low >> 32; 1064 d = dividend_low & 0xffffffff; 1065 1066 w = a / divisor; 1067 ra = ((u64)(a - (w * divisor)) << 32) + b; 1068 1069 rb = ((u64) do_div(ra, divisor) << 32) + c; 1070 x = ra; 1071 1072 rc = ((u64) do_div(rb, divisor) << 32) + d; 1073 y = rb; 1074 1075 do_div(rc, divisor); 1076 z = rc; 1077 1078 dr->result_high = ((u64)w << 32) + x; 1079 dr->result_low = ((u64)y << 32) + z; 1080 1081 } 1082 1083 /* We don't need to calibrate delay, we use the CPU timebase for that */ 1084 void calibrate_delay(void) 1085 { 1086 /* Some generic code (such as spinlock debug) use loops_per_jiffy 1087 * as the number of __delay(1) in a jiffy, so make it so 1088 */ 1089 loops_per_jiffy = tb_ticks_per_jiffy; 1090 } 1091 1092 #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC) 1093 static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) 1094 { 1095 ppc_md.get_rtc_time(tm); 1096 return 0; 1097 } 1098 1099 static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) 1100 { 1101 if (!ppc_md.set_rtc_time) 1102 return -EOPNOTSUPP; 1103 1104 if (ppc_md.set_rtc_time(tm) < 0) 1105 return -EOPNOTSUPP; 1106 1107 return 0; 1108 } 1109 1110 static const struct rtc_class_ops rtc_generic_ops = { 1111 .read_time = rtc_generic_get_time, 1112 .set_time = rtc_generic_set_time, 1113 }; 1114 1115 static int __init rtc_init(void) 1116 { 1117 struct platform_device *pdev; 1118 1119 if (!ppc_md.get_rtc_time) 1120 return -ENODEV; 1121 1122 pdev = platform_device_register_data(NULL, "rtc-generic", -1, 1123 &rtc_generic_ops, 1124 sizeof(rtc_generic_ops)); 1125 1126 return PTR_ERR_OR_ZERO(pdev); 1127 } 1128 1129 device_initcall(rtc_init); 1130 #endif 1131