2 * Local APIC handling, local APIC timers
4 * (c) 1999, 2000 Ingo Molnar <mingo@redhat.com>
7 * Maciej W. Rozycki : Bits for genuine 82489DX APICs;
8 * thanks to Eric Gilmore
10 * for testing these extensively.
11 * Maciej W. Rozycki : Various updates and fixes.
12 * Mikael Pettersson : Power Management for UP-APIC.
14 * Mikael Pettersson : PM converted to driver model.
17 #include <linux/config.h>
18 #include <linux/init.h>
21 #include <linux/irq.h>
22 #include <linux/delay.h>
23 #include <linux/bootmem.h>
24 #include <linux/smp_lock.h>
25 #include <linux/interrupt.h>
26 #include <linux/mc146818rtc.h>
27 #include <linux/kernel_stat.h>
28 #include <linux/sysdev.h>
30 #include <asm/atomic.h>
33 #include <asm/mpspec.h>
34 #include <asm/pgalloc.h>
35 #include <asm/mach_apic.h>
40 int disable_apic_timer __initdata;
42 /* Using APIC to generate smp_local_timer_interrupt? */
43 int using_apic_timer = 0;
45 static DEFINE_PER_CPU(int, prof_multiplier) = 1;
46 static DEFINE_PER_CPU(int, prof_old_multiplier) = 1;
47 static DEFINE_PER_CPU(int, prof_counter) = 1;
49 static void apic_pm_activate(void);
51 void enable_NMI_through_LVT0 (void * dummy)
55 ver = apic_read(APIC_LVR);
56 ver = GET_APIC_VERSION(ver);
57 v = APIC_DM_NMI; /* unmask and set to NMI */
58 apic_write_around(APIC_LVT0, v);
63 unsigned int v, ver, maxlvt;
65 v = apic_read(APIC_LVR);
66 ver = GET_APIC_VERSION(v);
67 maxlvt = GET_APIC_MAXLVT(v);
71 void clear_local_APIC(void)
76 maxlvt = get_maxlvt();
79 * Masking an LVT entry on a P6 can trigger a local APIC error
80 * if the vector is zero. Mask LVTERR first to prevent this.
83 v = ERROR_APIC_VECTOR; /* any non-zero vector will do */
84 apic_write_around(APIC_LVTERR, v | APIC_LVT_MASKED);
87 * Careful: we have to set masks only first to deassert
88 * any level-triggered sources.
90 v = apic_read(APIC_LVTT);
91 apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
92 v = apic_read(APIC_LVT0);
93 apic_write_around(APIC_LVT0, v | APIC_LVT_MASKED);
94 v = apic_read(APIC_LVT1);
95 apic_write_around(APIC_LVT1, v | APIC_LVT_MASKED);
97 v = apic_read(APIC_LVTPC);
98 apic_write_around(APIC_LVTPC, v | APIC_LVT_MASKED);
102 * Clean APIC state for other OSs:
104 apic_write_around(APIC_LVTT, APIC_LVT_MASKED);
105 apic_write_around(APIC_LVT0, APIC_LVT_MASKED);
106 apic_write_around(APIC_LVT1, APIC_LVT_MASKED);
108 apic_write_around(APIC_LVTERR, APIC_LVT_MASKED);
110 apic_write_around(APIC_LVTPC, APIC_LVT_MASKED);
111 v = GET_APIC_VERSION(apic_read(APIC_LVR));
112 if (APIC_INTEGRATED(v)) { /* !82489DX */
113 if (maxlvt > 3) /* Due to Pentium errata 3AP and 11AP. */
114 apic_write(APIC_ESR, 0);
119 void __init connect_bsp_APIC(void)
123 * Do not trust the local APIC being empty at bootup.
127 * PIC mode, enable APIC mode in the IMCR, i.e.
128 * connect BSP's local APIC to INT and NMI lines.
130 apic_printk(APIC_VERBOSE, "leaving PIC mode, enabling APIC mode.\n");
136 void disconnect_bsp_APIC(void)
140 * Put the board back into PIC mode (has an effect
141 * only on certain older boards). Note that APIC
142 * interrupts, including IPIs, won't work beyond
143 * this point! The only exception are INIT IPIs.
145 apic_printk(APIC_QUIET, "disabling APIC mode, entering PIC mode.\n");
150 /* Go back to Virtual Wire compatibility mode */
153 /* For the spurious interrupt use vector F, and enable it */
154 value = apic_read(APIC_SPIV);
155 value &= ~APIC_VECTOR_MASK;
156 value |= APIC_SPIV_APIC_ENABLED;
158 apic_write_around(APIC_SPIV, value);
160 /* For LVT0 make it edge triggered, active high, external and enabled */
161 value = apic_read(APIC_LVT0);
162 value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
163 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
164 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
165 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
166 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXINT);
167 apic_write_around(APIC_LVT0, value);
169 /* For LVT1 make it edge triggered, active high, nmi and enabled */
170 value = apic_read(APIC_LVT1);
172 APIC_MODE_MASK | APIC_SEND_PENDING |
173 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
174 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
175 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
176 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
177 apic_write_around(APIC_LVT1, value);
181 void disable_local_APIC(void)
188 * Disable APIC (implies clearing of registers
191 value = apic_read(APIC_SPIV);
192 value &= ~APIC_SPIV_APIC_ENABLED;
193 apic_write_around(APIC_SPIV, value);
197 * This is to verify that we're looking at a real local APIC.
198 * Check these against your board if the CPUs aren't getting
199 * started for no apparent reason.
201 int __init verify_local_APIC(void)
203 unsigned int reg0, reg1;
206 * The version register is read-only in a real APIC.
208 reg0 = apic_read(APIC_LVR);
209 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg0);
210 apic_write(APIC_LVR, reg0 ^ APIC_LVR_MASK);
211 reg1 = apic_read(APIC_LVR);
212 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg1);
215 * The two version reads above should print the same
216 * numbers. If the second one is different, then we
217 * poke at a non-APIC.
223 * Check if the version looks reasonably.
225 reg1 = GET_APIC_VERSION(reg0);
226 if (reg1 == 0x00 || reg1 == 0xff)
229 if (reg1 < 0x02 || reg1 == 0xff)
233 * The ID register is read/write in a real APIC.
235 reg0 = apic_read(APIC_ID);
236 apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg0);
237 apic_write(APIC_ID, reg0 ^ APIC_ID_MASK);
238 reg1 = apic_read(APIC_ID);
239 apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg1);
240 apic_write(APIC_ID, reg0);
241 if (reg1 != (reg0 ^ APIC_ID_MASK))
245 * The next two are just to see if we have sane values.
246 * They're only really relevant if we're in Virtual Wire
247 * compatibility mode, but most boxes are anymore.
249 reg0 = apic_read(APIC_LVT0);
250 apic_printk(APIC_DEBUG,"Getting LVT0: %x\n", reg0);
251 reg1 = apic_read(APIC_LVT1);
252 apic_printk(APIC_DEBUG, "Getting LVT1: %x\n", reg1);
257 void __init sync_Arb_IDs(void)
259 /* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 */
260 unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
261 if (ver >= 0x14) /* P4 or higher */
267 apic_wait_icr_idle();
269 apic_printk(APIC_DEBUG, "Synchronizing Arb IDs.\n");
270 apic_write_around(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG
274 extern void __error_in_apic_c (void);
277 * An initial setup of the virtual wire mode.
279 void __init init_bsp_APIC(void)
281 unsigned int value, ver;
284 * Don't do the setup now if we have a SMP BIOS as the
285 * through-I/O-APIC virtual wire mode might be active.
287 if (smp_found_config || !cpu_has_apic)
290 value = apic_read(APIC_LVR);
291 ver = GET_APIC_VERSION(value);
294 * Do not trust the local APIC being empty at bootup.
301 value = apic_read(APIC_SPIV);
302 value &= ~APIC_VECTOR_MASK;
303 value |= APIC_SPIV_APIC_ENABLED;
304 value |= APIC_SPIV_FOCUS_DISABLED;
305 value |= SPURIOUS_APIC_VECTOR;
306 apic_write_around(APIC_SPIV, value);
309 * Set up the virtual wire mode.
311 apic_write_around(APIC_LVT0, APIC_DM_EXTINT);
313 if (!APIC_INTEGRATED(ver)) /* 82489DX */
314 value |= APIC_LVT_LEVEL_TRIGGER;
315 apic_write_around(APIC_LVT1, value);
318 void __init setup_local_APIC (void)
320 unsigned int value, ver, maxlvt;
322 /* Pound the ESR really hard over the head with a big hammer - mbligh */
324 apic_write(APIC_ESR, 0);
325 apic_write(APIC_ESR, 0);
326 apic_write(APIC_ESR, 0);
327 apic_write(APIC_ESR, 0);
330 value = apic_read(APIC_LVR);
331 ver = GET_APIC_VERSION(value);
333 if ((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f)
337 * Double-check whether this APIC is really registered.
338 * This is meaningless in clustered apic mode, so we skip it.
340 if (!apic_id_registered())
344 * Intel recommends to set DFR, LDR and TPR before enabling
345 * an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel
346 * document number 292116). So here it goes...
351 * Set Task Priority to 'accept all'. We never change this
354 value = apic_read(APIC_TASKPRI);
355 value &= ~APIC_TPRI_MASK;
356 apic_write_around(APIC_TASKPRI, value);
359 * Now that we are all set up, enable the APIC
361 value = apic_read(APIC_SPIV);
362 value &= ~APIC_VECTOR_MASK;
366 value |= APIC_SPIV_APIC_ENABLED;
369 * Some unknown Intel IO/APIC (or APIC) errata is biting us with
370 * certain networking cards. If high frequency interrupts are
371 * happening on a particular IOAPIC pin, plus the IOAPIC routing
372 * entry is masked/unmasked at a high rate as well then sooner or
373 * later IOAPIC line gets 'stuck', no more interrupts are received
374 * from the device. If focus CPU is disabled then the hang goes
377 * [ This bug can be reproduced easily with a level-triggered
378 * PCI Ne2000 networking cards and PII/PIII processors, dual
382 * Actually disabling the focus CPU check just makes the hang less
383 * frequent as it makes the interrupt distributon model be more
384 * like LRU than MRU (the short-term load is more even across CPUs).
385 * See also the comment in end_level_ioapic_irq(). --macro
388 /* Enable focus processor (bit==0) */
389 value &= ~APIC_SPIV_FOCUS_DISABLED;
391 /* Disable focus processor (bit==1) */
392 value |= APIC_SPIV_FOCUS_DISABLED;
395 * Set spurious IRQ vector
397 value |= SPURIOUS_APIC_VECTOR;
398 apic_write_around(APIC_SPIV, value);
403 * set up through-local-APIC on the BP's LINT0. This is not
404 * strictly necessary in pure symmetric-IO mode, but sometimes
405 * we delegate interrupts to the 8259A.
408 * TODO: set up through-local-APIC from through-I/O-APIC? --macro
410 value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
411 if (!smp_processor_id() && (pic_mode || !value)) {
412 value = APIC_DM_EXTINT;
413 apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n", smp_processor_id());
415 value = APIC_DM_EXTINT | APIC_LVT_MASKED;
416 apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n", smp_processor_id());
418 apic_write_around(APIC_LVT0, value);
421 * only the BP should see the LINT1 NMI signal, obviously.
423 if (!smp_processor_id())
426 value = APIC_DM_NMI | APIC_LVT_MASKED;
427 if (!APIC_INTEGRATED(ver)) /* 82489DX */
428 value |= APIC_LVT_LEVEL_TRIGGER;
429 apic_write_around(APIC_LVT1, value);
431 if (APIC_INTEGRATED(ver) && !esr_disable) { /* !82489DX */
433 maxlvt = get_maxlvt();
434 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
435 apic_write(APIC_ESR, 0);
436 oldvalue = apic_read(APIC_ESR);
437 value = ERROR_APIC_VECTOR; // enables sending errors
438 apic_write_around(APIC_LVTERR, value);
440 * spec says clear errors after enabling vector.
443 apic_write(APIC_ESR, 0);
444 value = apic_read(APIC_ESR);
445 if (value != oldvalue)
446 apic_printk(APIC_VERBOSE,
447 "ESR value after enabling vector: %08x, after %08x\n",
452 * Something untraceble is creating bad interrupts on
453 * secondary quads ... for the moment, just leave the
454 * ESR disabled - we can't do anything useful with the
455 * errors anyway - mbligh
457 apic_printk(APIC_DEBUG, "Leaving ESR disabled.\n");
459 apic_printk(APIC_DEBUG, "No ESR for 82489DX.\n");
462 nmi_watchdog_default();
463 if (nmi_watchdog == NMI_LOCAL_APIC)
464 setup_apic_nmi_watchdog();
471 /* 'active' is true if the local APIC was enabled by us and
472 not the BIOS; this signifies that we are also responsible
473 for disabling it before entering apm/acpi suspend */
475 /* r/w apic fields */
476 unsigned int apic_id;
477 unsigned int apic_taskpri;
478 unsigned int apic_ldr;
479 unsigned int apic_dfr;
480 unsigned int apic_spiv;
481 unsigned int apic_lvtt;
482 unsigned int apic_lvtpc;
483 unsigned int apic_lvt0;
484 unsigned int apic_lvt1;
485 unsigned int apic_lvterr;
486 unsigned int apic_tmict;
487 unsigned int apic_tdcr;
488 unsigned int apic_thmr;
491 static int lapic_suspend(struct sys_device *dev, pm_message_t state)
495 if (!apic_pm_state.active)
498 apic_pm_state.apic_id = apic_read(APIC_ID);
499 apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
500 apic_pm_state.apic_ldr = apic_read(APIC_LDR);
501 apic_pm_state.apic_dfr = apic_read(APIC_DFR);
502 apic_pm_state.apic_spiv = apic_read(APIC_SPIV);
503 apic_pm_state.apic_lvtt = apic_read(APIC_LVTT);
504 apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC);
505 apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0);
506 apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1);
507 apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
508 apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
509 apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
510 apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
511 local_save_flags(flags);
513 disable_local_APIC();
514 local_irq_restore(flags);
518 static int lapic_resume(struct sys_device *dev)
523 if (!apic_pm_state.active)
526 /* XXX: Pavel needs this for S3 resume, but can't explain why */
527 set_fixmap_nocache(FIX_APIC_BASE, APIC_DEFAULT_PHYS_BASE);
529 local_irq_save(flags);
530 rdmsr(MSR_IA32_APICBASE, l, h);
531 l &= ~MSR_IA32_APICBASE_BASE;
532 l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
533 wrmsr(MSR_IA32_APICBASE, l, h);
534 apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
535 apic_write(APIC_ID, apic_pm_state.apic_id);
536 apic_write(APIC_DFR, apic_pm_state.apic_dfr);
537 apic_write(APIC_LDR, apic_pm_state.apic_ldr);
538 apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri);
539 apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
540 apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
541 apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
542 apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr);
543 apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
544 apic_write(APIC_LVTT, apic_pm_state.apic_lvtt);
545 apic_write(APIC_TDCR, apic_pm_state.apic_tdcr);
546 apic_write(APIC_TMICT, apic_pm_state.apic_tmict);
547 apic_write(APIC_ESR, 0);
549 apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr);
550 apic_write(APIC_ESR, 0);
552 local_irq_restore(flags);
556 static struct sysdev_class lapic_sysclass = {
557 set_kset_name("lapic"),
558 .resume = lapic_resume,
559 .suspend = lapic_suspend,
562 static struct sys_device device_lapic = {
564 .cls = &lapic_sysclass,
567 static void __init apic_pm_activate(void)
569 apic_pm_state.active = 1;
572 static int __init init_lapic_sysfs(void)
577 /* XXX: remove suspend/resume procs if !apic_pm_state.active? */
578 error = sysdev_class_register(&lapic_sysclass);
580 error = sysdev_register(&device_lapic);
583 device_initcall(init_lapic_sysfs);
585 #else /* CONFIG_PM */
587 static void apic_pm_activate(void) { }
589 #endif /* CONFIG_PM */
591 static int __init apic_set_verbosity(char *str)
593 if (strcmp("debug", str) == 0)
594 apic_verbosity = APIC_DEBUG;
595 else if (strcmp("verbose", str) == 0)
596 apic_verbosity = APIC_VERBOSE;
598 printk(KERN_WARNING "APIC Verbosity level %s not recognised"
599 " use apic=verbose or apic=debug", str);
604 __setup("apic=", apic_set_verbosity);
607 * Detect and enable local APICs on non-SMP boards.
608 * Original code written by Keir Fraser.
609 * On AMD64 we trust the BIOS - if it says no APIC it is likely
610 * not correctly set up (usually the APIC timer won't work etc.)
613 static int __init detect_init_APIC (void)
616 printk(KERN_INFO "No local APIC present\n");
620 mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
625 void __init init_apic_mappings(void)
627 unsigned long apic_phys;
630 * If no local APIC can be found then set up a fake all
631 * zeroes page to simulate the local APIC and another
632 * one for the IO-APIC.
634 if (!smp_found_config && detect_init_APIC()) {
635 apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
636 apic_phys = __pa(apic_phys);
638 apic_phys = mp_lapic_addr;
640 set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
641 apic_printk(APIC_VERBOSE,"mapped APIC to %16lx (%16lx)\n", APIC_BASE, apic_phys);
644 * Fetch the APIC ID of the BSP in case we have a
645 * default configuration (or the MP table is broken).
647 if (boot_cpu_id == -1U)
648 boot_cpu_id = GET_APIC_ID(apic_read(APIC_ID));
650 #ifdef CONFIG_X86_IO_APIC
652 unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
655 for (i = 0; i < nr_ioapics; i++) {
656 if (smp_found_config) {
657 ioapic_phys = mp_ioapics[i].mpc_apicaddr;
659 ioapic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
660 ioapic_phys = __pa(ioapic_phys);
662 set_fixmap_nocache(idx, ioapic_phys);
663 apic_printk(APIC_VERBOSE,"mapped IOAPIC to %016lx (%016lx)\n",
664 __fix_to_virt(idx), ioapic_phys);
672 * This function sets up the local APIC timer, with a timeout of
673 * 'clocks' APIC bus clock. During calibration we actually call
674 * this function twice on the boot CPU, once with a bogus timeout
675 * value, second time for real. The other (noncalibrating) CPUs
676 * call this function only once, with the real, calibrated value.
678 * We do reads before writes even if unnecessary, to get around the
679 * P5 APIC double write bug.
682 #define APIC_DIVISOR 16
684 static void __setup_APIC_LVTT(unsigned int clocks)
686 unsigned int lvtt_value, tmp_value, ver;
688 ver = GET_APIC_VERSION(apic_read(APIC_LVR));
689 lvtt_value = APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR;
690 if (!APIC_INTEGRATED(ver))
691 lvtt_value |= SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV);
692 apic_write_around(APIC_LVTT, lvtt_value);
697 tmp_value = apic_read(APIC_TDCR);
698 apic_write_around(APIC_TDCR, (tmp_value
699 & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE))
702 apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR);
705 static void setup_APIC_timer(unsigned int clocks)
709 local_irq_save(flags);
711 /* For some reasons this doesn't work on Simics, so fake it for now */
712 if (!strstr(boot_cpu_data.x86_model_id, "Screwdriver")) {
713 __setup_APIC_LVTT(clocks);
717 /* wait for irq slice */
718 if (vxtime.hpet_address) {
719 int trigger = hpet_readl(HPET_T0_CMP);
720 while (hpet_readl(HPET_COUNTER) >= trigger)
722 while (hpet_readl(HPET_COUNTER) < trigger)
728 c2 |= inb_p(0x40) << 8;
733 c2 |= inb_p(0x40) << 8;
734 } while (c2 - c1 < 300);
737 __setup_APIC_LVTT(clocks);
739 local_irq_restore(flags);
743 * In this function we calibrate APIC bus clocks to the external
744 * timer. Unfortunately we cannot use jiffies and the timer irq
745 * to calibrate, since some later bootup code depends on getting
746 * the first irq? Ugh.
748 * We want to do the calibration only once since we
749 * want to have local timer irqs syncron. CPUs connected
750 * by the same APIC bus have the very same bus frequency.
751 * And we want to have irqs off anyways, no accidental
755 #define TICK_COUNT 100000000
757 static int __init calibrate_APIC_clock(void)
759 int apic, apic_start, tsc, tsc_start;
762 * Put whatever arbitrary (but long enough) timeout
763 * value into the APIC clock, we just want to get the
764 * counter running for calibration.
766 __setup_APIC_LVTT(1000000000);
768 apic_start = apic_read(APIC_TMCCT);
772 apic = apic_read(APIC_TMCCT);
774 } while ((tsc - tsc_start) < TICK_COUNT && (apic - apic_start) < TICK_COUNT);
776 result = (apic_start - apic) * 1000L * cpu_khz / (tsc - tsc_start);
778 printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n",
779 result / 1000 / 1000, result / 1000 % 1000);
781 return result * APIC_DIVISOR / HZ;
784 static unsigned int calibration_result;
786 void __init setup_boot_APIC_clock (void)
788 if (disable_apic_timer) {
789 printk(KERN_INFO "Disabling APIC timer\n");
793 printk(KERN_INFO "Using local APIC timer interrupts.\n");
794 using_apic_timer = 1;
798 calibration_result = calibrate_APIC_clock();
800 * Now set up the timer for real.
802 setup_APIC_timer(calibration_result);
807 void __init setup_secondary_APIC_clock(void)
809 local_irq_disable(); /* FIXME: Do we need this? --RR */
810 setup_APIC_timer(calibration_result);
814 void __init disable_APIC_timer(void)
816 if (using_apic_timer) {
819 v = apic_read(APIC_LVTT);
820 apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
824 void enable_APIC_timer(void)
826 if (using_apic_timer) {
829 v = apic_read(APIC_LVTT);
830 apic_write_around(APIC_LVTT, v & ~APIC_LVT_MASKED);
835 * the frequency of the profiling timer can be changed
836 * by writing a multiplier value into /proc/profile.
838 int setup_profiling_timer(unsigned int multiplier)
843 * Sanity check. [at least 500 APIC cycles should be
844 * between APIC interrupts as a rule of thumb, to avoid
847 if ( (!multiplier) || (calibration_result/multiplier < 500))
851 * Set the new multiplier for each CPU. CPUs don't start using the
852 * new values until the next timer interrupt in which they do process
853 * accounting. At that time they also adjust their APIC timers
856 for (i = 0; i < NR_CPUS; ++i)
857 per_cpu(prof_multiplier, i) = multiplier;
865 * Local timer interrupt handler. It does both profiling and
866 * process statistics/rescheduling.
868 * We do profiling in every local tick, statistics/rescheduling
869 * happen only every 'profiling multiplier' ticks. The default
870 * multiplier is 1 and it can be changed by writing the new multiplier
871 * value into /proc/profile.
874 void smp_local_timer_interrupt(struct pt_regs *regs)
876 int cpu = smp_processor_id();
878 profile_tick(CPU_PROFILING, regs);
879 if (--per_cpu(prof_counter, cpu) <= 0) {
881 * The multiplier may have changed since the last time we got
882 * to this point as a result of the user writing to
883 * /proc/profile. In this case we need to adjust the APIC
886 * Interrupts are already masked off at this point.
888 per_cpu(prof_counter, cpu) = per_cpu(prof_multiplier, cpu);
889 if (per_cpu(prof_counter, cpu) !=
890 per_cpu(prof_old_multiplier, cpu)) {
891 __setup_APIC_LVTT(calibration_result/
892 per_cpu(prof_counter, cpu));
893 per_cpu(prof_old_multiplier, cpu) =
894 per_cpu(prof_counter, cpu);
898 update_process_times(user_mode(regs));
903 * We take the 'long' return path, and there every subsystem
904 * grabs the appropriate locks (kernel lock/ irq lock).
906 * we might want to decouple profiling from the 'long path',
907 * and do the profiling totally in assembly.
909 * Currently this isn't too much of an issue (performance wise),
910 * we can take more than 100K local irqs per second on a 100 MHz P5.
915 * Local APIC timer interrupt. This is the most natural way for doing
916 * local interrupts, but local timer interrupts can be emulated by
917 * broadcast interrupts too. [in case the hw doesn't support APIC timers]
919 * [ if a single-CPU system runs an SMP kernel then we call the local
920 * interrupt as well. Thus we cannot inline the local irq ... ]
922 void smp_apic_timer_interrupt(struct pt_regs *regs)
925 * the NMI deadlock-detector uses this.
927 add_pda(apic_timer_irqs, 1);
930 * NOTE! We'd better ACK the irq immediately,
931 * because timer handling can be slow.
935 * update_process_times() expects us to have done irq_enter().
936 * Besides, if we don't timer interrupts ignore the global
937 * interrupt lock, which is the WrongThing (tm) to do.
940 smp_local_timer_interrupt(regs);
945 * oem_force_hpet_timer -- force HPET mode for some boxes.
947 * Thus far, the major user of this is IBM's Summit2 series:
949 * Clustered boxes may have unsynced TSC problems if they are
950 * multi-chassis. Use available data to take a good guess.
951 * If in doubt, go HPET.
953 __init int oem_force_hpet_timer(void)
955 int i, clusters, zeros;
957 DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);
959 bitmap_zero(clustermap, NUM_APIC_CLUSTERS);
961 for (i = 0; i < NR_CPUS; i++) {
962 id = bios_cpu_apicid[i];
963 if (id != BAD_APICID)
964 __set_bit(APIC_CLUSTERID(id), clustermap);
967 /* Problem: Partially populated chassis may not have CPUs in some of
968 * the APIC clusters they have been allocated. Only present CPUs have
969 * bios_cpu_apicid entries, thus causing zeroes in the bitmap. Since
970 * clusters are allocated sequentially, count zeros only if they are
975 for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
976 if (test_bit(i, clustermap)) {
977 clusters += 1 + zeros;
984 * If clusters > 2, then should be multi-chassis. Return 1 for HPET.
985 * Else return 0 to use TSC.
986 * May have to revisit this when multi-core + hyperthreaded CPUs come
987 * out, but AFAIK this will work even for them.
989 return (clusters > 2);
993 * This interrupt should _never_ happen with our APIC/SMP architecture
995 asmlinkage void smp_spurious_interrupt(void)
1000 * Check if this really is a spurious interrupt and ACK it
1001 * if it is a vectored one. Just in case...
1002 * Spurious interrupts should not be ACKed.
1004 v = apic_read(APIC_ISR + ((SPURIOUS_APIC_VECTOR & ~0x1f) >> 1));
1005 if (v & (1 << (SPURIOUS_APIC_VECTOR & 0x1f)))
1009 static unsigned long last_warning;
1010 static unsigned long skipped;
1012 /* see sw-dev-man vol 3, chapter 7.4.13.5 */
1013 if (time_before(last_warning+30*HZ,jiffies)) {
1014 printk(KERN_INFO "spurious APIC interrupt on CPU#%d, %ld skipped.\n",
1015 smp_processor_id(), skipped);
1016 last_warning = jiffies;
1026 * This interrupt should never happen with our APIC/SMP architecture
1029 asmlinkage void smp_error_interrupt(void)
1034 /* First tickle the hardware, only then report what went on. -- REW */
1035 v = apic_read(APIC_ESR);
1036 apic_write(APIC_ESR, 0);
1037 v1 = apic_read(APIC_ESR);
1039 atomic_inc(&irq_err_count);
1041 /* Here is what the APIC error bits mean:
1044 2: Send accept error
1045 3: Receive accept error
1047 5: Send illegal vector
1048 6: Received illegal vector
1049 7: Illegal register address
1051 printk (KERN_DEBUG "APIC error on CPU%d: %02x(%02x)\n",
1052 smp_processor_id(), v , v1);
1059 * This initializes the IO-APIC and APIC hardware if this is
1062 int __init APIC_init_uniprocessor (void)
1065 printk(KERN_INFO "Apic disabled\n");
1068 if (!cpu_has_apic) {
1070 printk(KERN_INFO "Apic disabled by BIOS\n");
1074 verify_local_APIC();
1078 phys_cpu_present_map = physid_mask_of_physid(0);
1079 apic_write_around(APIC_ID, boot_cpu_id);
1083 #ifdef CONFIG_X86_IO_APIC
1084 if (smp_found_config && !skip_ioapic_setup && nr_ioapics)
1089 setup_boot_APIC_clock();
1090 check_nmi_watchdog();
1094 static __init int setup_disableapic(char *str)
1100 static __init int setup_nolapic(char *str)
1106 static __init int setup_noapictimer(char *str)
1108 disable_apic_timer = 1;
1112 /* dummy parsing: see setup.c */
1114 __setup("disableapic", setup_disableapic);
1115 __setup("nolapic", setup_nolapic); /* same as disableapic, for compatibility */
1117 __setup("noapictimer", setup_noapictimer);
1119 /* no "lapic" flag - we only use the lapic when the BIOS tells us so. */