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>
29 #include <linux/cpu.h>
31 #include <asm/atomic.h>
34 #include <asm/mpspec.h>
36 #include <asm/arch_hooks.h>
38 #include <asm/i8253.h>
40 #include <mach_apic.h>
45 * Knob to control our willingness to enable the local APIC.
47 int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */
55 static void apic_pm_activate(void);
58 * 'what should we do if we get a hw irq event on an illegal vector'.
59 * each architecture has to answer this themselves.
61 void ack_bad_irq(unsigned int irq)
63 printk("unexpected IRQ trap at vector %02x\n", irq);
65 * Currently unexpected vectors happen only on SMP and APIC.
66 * We _must_ ack these because every local APIC has only N
67 * irq slots per priority level, and a 'hanging, unacked' IRQ
68 * holds up an irq slot - in excessive cases (when multiple
69 * unexpected vectors occur) that might lock up the APIC
75 void __init apic_intr_init(void)
80 /* self generated IPI for local APIC timer */
81 set_intr_gate(LOCAL_TIMER_VECTOR, apic_timer_interrupt);
83 /* IPI vectors for APIC spurious and error interrupts */
84 set_intr_gate(SPURIOUS_APIC_VECTOR, spurious_interrupt);
85 set_intr_gate(ERROR_APIC_VECTOR, error_interrupt);
87 /* thermal monitor LVT interrupt */
88 #ifdef CONFIG_X86_MCE_P4THERMAL
89 set_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt);
93 /* Using APIC to generate smp_local_timer_interrupt? */
94 int using_apic_timer = 0;
96 static DEFINE_PER_CPU(int, prof_multiplier) = 1;
97 static DEFINE_PER_CPU(int, prof_old_multiplier) = 1;
98 static DEFINE_PER_CPU(int, prof_counter) = 1;
100 static int enabled_via_apicbase;
102 void enable_NMI_through_LVT0 (void * dummy)
106 ver = apic_read(APIC_LVR);
107 ver = GET_APIC_VERSION(ver);
108 v = APIC_DM_NMI; /* unmask and set to NMI */
109 if (!APIC_INTEGRATED(ver)) /* 82489DX */
110 v |= APIC_LVT_LEVEL_TRIGGER;
111 apic_write_around(APIC_LVT0, v);
114 int get_physical_broadcast(void)
116 unsigned int lvr, version;
117 lvr = apic_read(APIC_LVR);
118 version = GET_APIC_VERSION(lvr);
119 if (!APIC_INTEGRATED(version) || version >= 0x14)
127 unsigned int v, ver, maxlvt;
129 v = apic_read(APIC_LVR);
130 ver = GET_APIC_VERSION(v);
131 /* 82489DXs do not report # of LVT entries. */
132 maxlvt = APIC_INTEGRATED(ver) ? GET_APIC_MAXLVT(v) : 2;
136 void clear_local_APIC(void)
141 maxlvt = get_maxlvt();
144 * Masking an LVT entry on a P6 can trigger a local APIC error
145 * if the vector is zero. Mask LVTERR first to prevent this.
148 v = ERROR_APIC_VECTOR; /* any non-zero vector will do */
149 apic_write_around(APIC_LVTERR, v | APIC_LVT_MASKED);
152 * Careful: we have to set masks only first to deassert
153 * any level-triggered sources.
155 v = apic_read(APIC_LVTT);
156 apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
157 v = apic_read(APIC_LVT0);
158 apic_write_around(APIC_LVT0, v | APIC_LVT_MASKED);
159 v = apic_read(APIC_LVT1);
160 apic_write_around(APIC_LVT1, v | APIC_LVT_MASKED);
162 v = apic_read(APIC_LVTPC);
163 apic_write_around(APIC_LVTPC, v | APIC_LVT_MASKED);
166 /* lets not touch this if we didn't frob it */
167 #ifdef CONFIG_X86_MCE_P4THERMAL
169 v = apic_read(APIC_LVTTHMR);
170 apic_write_around(APIC_LVTTHMR, v | APIC_LVT_MASKED);
174 * Clean APIC state for other OSs:
176 apic_write_around(APIC_LVTT, APIC_LVT_MASKED);
177 apic_write_around(APIC_LVT0, APIC_LVT_MASKED);
178 apic_write_around(APIC_LVT1, APIC_LVT_MASKED);
180 apic_write_around(APIC_LVTERR, APIC_LVT_MASKED);
182 apic_write_around(APIC_LVTPC, APIC_LVT_MASKED);
184 #ifdef CONFIG_X86_MCE_P4THERMAL
186 apic_write_around(APIC_LVTTHMR, APIC_LVT_MASKED);
188 v = GET_APIC_VERSION(apic_read(APIC_LVR));
189 if (APIC_INTEGRATED(v)) { /* !82489DX */
190 if (maxlvt > 3) /* Due to Pentium errata 3AP and 11AP. */
191 apic_write(APIC_ESR, 0);
196 void __init connect_bsp_APIC(void)
200 * Do not trust the local APIC being empty at bootup.
204 * PIC mode, enable APIC mode in the IMCR, i.e.
205 * connect BSP's local APIC to INT and NMI lines.
207 apic_printk(APIC_VERBOSE, "leaving PIC mode, "
208 "enabling APIC mode.\n");
215 void disconnect_bsp_APIC(int virt_wire_setup)
219 * Put the board back into PIC mode (has an effect
220 * only on certain older boards). Note that APIC
221 * interrupts, including IPIs, won't work beyond
222 * this point! The only exception are INIT IPIs.
224 apic_printk(APIC_VERBOSE, "disabling APIC mode, "
225 "entering PIC mode.\n");
230 /* Go back to Virtual Wire compatibility mode */
233 /* For the spurious interrupt use vector F, and enable it */
234 value = apic_read(APIC_SPIV);
235 value &= ~APIC_VECTOR_MASK;
236 value |= APIC_SPIV_APIC_ENABLED;
238 apic_write_around(APIC_SPIV, value);
240 if (!virt_wire_setup) {
241 /* For LVT0 make it edge triggered, active high, external and enabled */
242 value = apic_read(APIC_LVT0);
243 value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
244 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
245 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
246 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
247 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT);
248 apic_write_around(APIC_LVT0, value);
252 apic_write_around(APIC_LVT0, APIC_LVT_MASKED);
255 /* For LVT1 make it edge triggered, active high, nmi and enabled */
256 value = apic_read(APIC_LVT1);
258 APIC_MODE_MASK | APIC_SEND_PENDING |
259 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
260 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
261 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
262 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
263 apic_write_around(APIC_LVT1, value);
267 void disable_local_APIC(void)
274 * Disable APIC (implies clearing of registers
277 value = apic_read(APIC_SPIV);
278 value &= ~APIC_SPIV_APIC_ENABLED;
279 apic_write_around(APIC_SPIV, value);
281 if (enabled_via_apicbase) {
283 rdmsr(MSR_IA32_APICBASE, l, h);
284 l &= ~MSR_IA32_APICBASE_ENABLE;
285 wrmsr(MSR_IA32_APICBASE, l, h);
290 * This is to verify that we're looking at a real local APIC.
291 * Check these against your board if the CPUs aren't getting
292 * started for no apparent reason.
294 int __init verify_local_APIC(void)
296 unsigned int reg0, reg1;
299 * The version register is read-only in a real APIC.
301 reg0 = apic_read(APIC_LVR);
302 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg0);
303 apic_write(APIC_LVR, reg0 ^ APIC_LVR_MASK);
304 reg1 = apic_read(APIC_LVR);
305 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg1);
308 * The two version reads above should print the same
309 * numbers. If the second one is different, then we
310 * poke at a non-APIC.
316 * Check if the version looks reasonably.
318 reg1 = GET_APIC_VERSION(reg0);
319 if (reg1 == 0x00 || reg1 == 0xff)
322 if (reg1 < 0x02 || reg1 == 0xff)
326 * The ID register is read/write in a real APIC.
328 reg0 = apic_read(APIC_ID);
329 apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg0);
332 * The next two are just to see if we have sane values.
333 * They're only really relevant if we're in Virtual Wire
334 * compatibility mode, but most boxes are anymore.
336 reg0 = apic_read(APIC_LVT0);
337 apic_printk(APIC_DEBUG, "Getting LVT0: %x\n", reg0);
338 reg1 = apic_read(APIC_LVT1);
339 apic_printk(APIC_DEBUG, "Getting LVT1: %x\n", reg1);
344 void __init sync_Arb_IDs(void)
346 /* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 */
347 unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
348 if (ver >= 0x14) /* P4 or higher */
353 apic_wait_icr_idle();
355 apic_printk(APIC_DEBUG, "Synchronizing Arb IDs.\n");
356 apic_write_around(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG
360 extern void __error_in_apic_c (void);
363 * An initial setup of the virtual wire mode.
365 void __init init_bsp_APIC(void)
367 unsigned long value, ver;
370 * Don't do the setup now if we have a SMP BIOS as the
371 * through-I/O-APIC virtual wire mode might be active.
373 if (smp_found_config || !cpu_has_apic)
376 value = apic_read(APIC_LVR);
377 ver = GET_APIC_VERSION(value);
380 * Do not trust the local APIC being empty at bootup.
387 value = apic_read(APIC_SPIV);
388 value &= ~APIC_VECTOR_MASK;
389 value |= APIC_SPIV_APIC_ENABLED;
391 /* This bit is reserved on P4/Xeon and should be cleared */
392 if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 15))
393 value &= ~APIC_SPIV_FOCUS_DISABLED;
395 value |= APIC_SPIV_FOCUS_DISABLED;
396 value |= SPURIOUS_APIC_VECTOR;
397 apic_write_around(APIC_SPIV, value);
400 * Set up the virtual wire mode.
402 apic_write_around(APIC_LVT0, APIC_DM_EXTINT);
404 if (!APIC_INTEGRATED(ver)) /* 82489DX */
405 value |= APIC_LVT_LEVEL_TRIGGER;
406 apic_write_around(APIC_LVT1, value);
409 void __devinit setup_local_APIC(void)
411 unsigned long oldvalue, value, ver, maxlvt;
413 /* Pound the ESR really hard over the head with a big hammer - mbligh */
415 apic_write(APIC_ESR, 0);
416 apic_write(APIC_ESR, 0);
417 apic_write(APIC_ESR, 0);
418 apic_write(APIC_ESR, 0);
421 value = apic_read(APIC_LVR);
422 ver = GET_APIC_VERSION(value);
424 if ((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f)
428 * Double-check whether this APIC is really registered.
430 if (!apic_id_registered())
434 * Intel recommends to set DFR, LDR and TPR before enabling
435 * an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel
436 * document number 292116). So here it goes...
441 * Set Task Priority to 'accept all'. We never change this
444 value = apic_read(APIC_TASKPRI);
445 value &= ~APIC_TPRI_MASK;
446 apic_write_around(APIC_TASKPRI, value);
449 * Now that we are all set up, enable the APIC
451 value = apic_read(APIC_SPIV);
452 value &= ~APIC_VECTOR_MASK;
456 value |= APIC_SPIV_APIC_ENABLED;
459 * Some unknown Intel IO/APIC (or APIC) errata is biting us with
460 * certain networking cards. If high frequency interrupts are
461 * happening on a particular IOAPIC pin, plus the IOAPIC routing
462 * entry is masked/unmasked at a high rate as well then sooner or
463 * later IOAPIC line gets 'stuck', no more interrupts are received
464 * from the device. If focus CPU is disabled then the hang goes
467 * [ This bug can be reproduced easily with a level-triggered
468 * PCI Ne2000 networking cards and PII/PIII processors, dual
472 * Actually disabling the focus CPU check just makes the hang less
473 * frequent as it makes the interrupt distributon model be more
474 * like LRU than MRU (the short-term load is more even across CPUs).
475 * See also the comment in end_level_ioapic_irq(). --macro
478 /* Enable focus processor (bit==0) */
479 value &= ~APIC_SPIV_FOCUS_DISABLED;
481 /* Disable focus processor (bit==1) */
482 value |= APIC_SPIV_FOCUS_DISABLED;
485 * Set spurious IRQ vector
487 value |= SPURIOUS_APIC_VECTOR;
488 apic_write_around(APIC_SPIV, value);
493 * set up through-local-APIC on the BP's LINT0. This is not
494 * strictly necessery in pure symmetric-IO mode, but sometimes
495 * we delegate interrupts to the 8259A.
498 * TODO: set up through-local-APIC from through-I/O-APIC? --macro
500 value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
501 if (!smp_processor_id() && (pic_mode || !value)) {
502 value = APIC_DM_EXTINT;
503 apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n",
506 value = APIC_DM_EXTINT | APIC_LVT_MASKED;
507 apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n",
510 apic_write_around(APIC_LVT0, value);
513 * only the BP should see the LINT1 NMI signal, obviously.
515 if (!smp_processor_id())
518 value = APIC_DM_NMI | APIC_LVT_MASKED;
519 if (!APIC_INTEGRATED(ver)) /* 82489DX */
520 value |= APIC_LVT_LEVEL_TRIGGER;
521 apic_write_around(APIC_LVT1, value);
523 if (APIC_INTEGRATED(ver) && !esr_disable) { /* !82489DX */
524 maxlvt = get_maxlvt();
525 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
526 apic_write(APIC_ESR, 0);
527 oldvalue = apic_read(APIC_ESR);
529 value = ERROR_APIC_VECTOR; // enables sending errors
530 apic_write_around(APIC_LVTERR, value);
532 * spec says clear errors after enabling vector.
535 apic_write(APIC_ESR, 0);
536 value = apic_read(APIC_ESR);
537 if (value != oldvalue)
538 apic_printk(APIC_VERBOSE, "ESR value before enabling "
539 "vector: 0x%08lx after: 0x%08lx\n",
544 * Something untraceble is creating bad interrupts on
545 * secondary quads ... for the moment, just leave the
546 * ESR disabled - we can't do anything useful with the
547 * errors anyway - mbligh
549 printk("Leaving ESR disabled.\n");
551 printk("No ESR for 82489DX.\n");
554 if (nmi_watchdog == NMI_LOCAL_APIC)
555 setup_apic_nmi_watchdog();
560 * If Linux enabled the LAPIC against the BIOS default
561 * disable it down before re-entering the BIOS on shutdown.
562 * Otherwise the BIOS may get confused and not power-off.
564 void lapic_shutdown(void)
566 if (!cpu_has_apic || !enabled_via_apicbase)
570 disable_local_APIC();
578 /* r/w apic fields */
579 unsigned int apic_id;
580 unsigned int apic_taskpri;
581 unsigned int apic_ldr;
582 unsigned int apic_dfr;
583 unsigned int apic_spiv;
584 unsigned int apic_lvtt;
585 unsigned int apic_lvtpc;
586 unsigned int apic_lvt0;
587 unsigned int apic_lvt1;
588 unsigned int apic_lvterr;
589 unsigned int apic_tmict;
590 unsigned int apic_tdcr;
591 unsigned int apic_thmr;
594 static int lapic_suspend(struct sys_device *dev, pm_message_t state)
598 if (!apic_pm_state.active)
601 apic_pm_state.apic_id = apic_read(APIC_ID);
602 apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
603 apic_pm_state.apic_ldr = apic_read(APIC_LDR);
604 apic_pm_state.apic_dfr = apic_read(APIC_DFR);
605 apic_pm_state.apic_spiv = apic_read(APIC_SPIV);
606 apic_pm_state.apic_lvtt = apic_read(APIC_LVTT);
607 apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC);
608 apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0);
609 apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1);
610 apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
611 apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
612 apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
613 apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
615 local_irq_save(flags);
616 disable_local_APIC();
617 local_irq_restore(flags);
621 static int lapic_resume(struct sys_device *dev)
626 if (!apic_pm_state.active)
629 local_irq_save(flags);
632 * Make sure the APICBASE points to the right address
634 * FIXME! This will be wrong if we ever support suspend on
635 * SMP! We'll need to do this as part of the CPU restore!
637 rdmsr(MSR_IA32_APICBASE, l, h);
638 l &= ~MSR_IA32_APICBASE_BASE;
639 l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr;
640 wrmsr(MSR_IA32_APICBASE, l, h);
642 apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
643 apic_write(APIC_ID, apic_pm_state.apic_id);
644 apic_write(APIC_DFR, apic_pm_state.apic_dfr);
645 apic_write(APIC_LDR, apic_pm_state.apic_ldr);
646 apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri);
647 apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
648 apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
649 apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
650 apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr);
651 apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
652 apic_write(APIC_LVTT, apic_pm_state.apic_lvtt);
653 apic_write(APIC_TDCR, apic_pm_state.apic_tdcr);
654 apic_write(APIC_TMICT, apic_pm_state.apic_tmict);
655 apic_write(APIC_ESR, 0);
657 apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr);
658 apic_write(APIC_ESR, 0);
660 local_irq_restore(flags);
665 * This device has no shutdown method - fully functioning local APICs
666 * are needed on every CPU up until machine_halt/restart/poweroff.
669 static struct sysdev_class lapic_sysclass = {
670 set_kset_name("lapic"),
671 .resume = lapic_resume,
672 .suspend = lapic_suspend,
675 static struct sys_device device_lapic = {
677 .cls = &lapic_sysclass,
680 static void __devinit apic_pm_activate(void)
682 apic_pm_state.active = 1;
685 static int __init init_lapic_sysfs(void)
691 /* XXX: remove suspend/resume procs if !apic_pm_state.active? */
693 error = sysdev_class_register(&lapic_sysclass);
695 error = sysdev_register(&device_lapic);
698 device_initcall(init_lapic_sysfs);
700 #else /* CONFIG_PM */
702 static void apic_pm_activate(void) { }
704 #endif /* CONFIG_PM */
707 * Detect and enable local APICs on non-SMP boards.
708 * Original code written by Keir Fraser.
711 static int __init apic_set_verbosity(char *str)
713 if (strcmp("debug", str) == 0)
714 apic_verbosity = APIC_DEBUG;
715 else if (strcmp("verbose", str) == 0)
716 apic_verbosity = APIC_VERBOSE;
718 printk(KERN_WARNING "APIC Verbosity level %s not recognised"
719 " use apic=verbose or apic=debug", str);
724 __setup("apic=", apic_set_verbosity);
726 static int __init detect_init_APIC (void)
730 /* Disabled by kernel option? */
731 if (enable_local_apic < 0)
734 switch (boot_cpu_data.x86_vendor) {
736 if ((boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model > 1) ||
737 (boot_cpu_data.x86 == 15))
740 case X86_VENDOR_INTEL:
741 if (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15 ||
742 (boot_cpu_data.x86 == 5 && cpu_has_apic))
751 * Over-ride BIOS and try to enable the local
752 * APIC only if "lapic" specified.
754 if (enable_local_apic <= 0) {
755 printk("Local APIC disabled by BIOS -- "
756 "you can enable it with \"lapic\"\n");
760 * Some BIOSes disable the local APIC in the
761 * APIC_BASE MSR. This can only be done in
762 * software for Intel P6 or later and AMD K7
763 * (Model > 1) or later.
765 rdmsr(MSR_IA32_APICBASE, l, h);
766 if (!(l & MSR_IA32_APICBASE_ENABLE)) {
767 printk("Local APIC disabled by BIOS -- reenabling.\n");
768 l &= ~MSR_IA32_APICBASE_BASE;
769 l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
770 wrmsr(MSR_IA32_APICBASE, l, h);
771 enabled_via_apicbase = 1;
775 * The APIC feature bit should now be enabled
778 features = cpuid_edx(1);
779 if (!(features & (1 << X86_FEATURE_APIC))) {
780 printk("Could not enable APIC!\n");
783 set_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
784 mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
786 /* The BIOS may have set up the APIC at some other address */
787 rdmsr(MSR_IA32_APICBASE, l, h);
788 if (l & MSR_IA32_APICBASE_ENABLE)
789 mp_lapic_addr = l & MSR_IA32_APICBASE_BASE;
791 if (nmi_watchdog != NMI_NONE)
792 nmi_watchdog = NMI_LOCAL_APIC;
794 printk("Found and enabled local APIC!\n");
801 printk("No local APIC present or hardware disabled\n");
805 void __init init_apic_mappings(void)
807 unsigned long apic_phys;
810 * If no local APIC can be found then set up a fake all
811 * zeroes page to simulate the local APIC and another
812 * one for the IO-APIC.
814 if (!smp_found_config && detect_init_APIC()) {
815 apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
816 apic_phys = __pa(apic_phys);
818 apic_phys = mp_lapic_addr;
820 set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
821 printk(KERN_DEBUG "mapped APIC to %08lx (%08lx)\n", APIC_BASE,
825 * Fetch the APIC ID of the BSP in case we have a
826 * default configuration (or the MP table is broken).
828 if (boot_cpu_physical_apicid == -1U)
829 boot_cpu_physical_apicid = GET_APIC_ID(apic_read(APIC_ID));
831 #ifdef CONFIG_X86_IO_APIC
833 unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
836 for (i = 0; i < nr_ioapics; i++) {
837 if (smp_found_config) {
838 ioapic_phys = mp_ioapics[i].mpc_apicaddr;
841 "WARNING: bogus zero IO-APIC "
842 "address found in MPTABLE, "
843 "disabling IO/APIC support!\n");
844 smp_found_config = 0;
845 skip_ioapic_setup = 1;
846 goto fake_ioapic_page;
850 ioapic_phys = (unsigned long)
851 alloc_bootmem_pages(PAGE_SIZE);
852 ioapic_phys = __pa(ioapic_phys);
854 set_fixmap_nocache(idx, ioapic_phys);
855 printk(KERN_DEBUG "mapped IOAPIC to %08lx (%08lx)\n",
856 __fix_to_virt(idx), ioapic_phys);
864 * This part sets up the APIC 32 bit clock in LVTT1, with HZ interrupts
865 * per second. We assume that the caller has already set up the local
868 * The APIC timer is not exactly sync with the external timer chip, it
869 * closely follows bus clocks.
873 * The timer chip is already set up at HZ interrupts per second here,
874 * but we do not accept timer interrupts yet. We only allow the BP
877 static unsigned int __devinit get_8254_timer_count(void)
883 spin_lock_irqsave(&i8253_lock, flags);
885 outb_p(0x00, PIT_MODE);
886 count = inb_p(PIT_CH0);
887 count |= inb_p(PIT_CH0) << 8;
889 spin_unlock_irqrestore(&i8253_lock, flags);
894 /* next tick in 8254 can be caught by catching timer wraparound */
895 static void __devinit wait_8254_wraparound(void)
897 unsigned int curr_count, prev_count;
899 curr_count = get_8254_timer_count();
901 prev_count = curr_count;
902 curr_count = get_8254_timer_count();
904 /* workaround for broken Mercury/Neptune */
905 if (prev_count >= curr_count + 0x100)
906 curr_count = get_8254_timer_count();
908 } while (prev_count >= curr_count);
912 * Default initialization for 8254 timers. If we use other timers like HPET,
913 * we override this later
915 void (*wait_timer_tick)(void) __devinitdata = wait_8254_wraparound;
918 * This function sets up the local APIC timer, with a timeout of
919 * 'clocks' APIC bus clock. During calibration we actually call
920 * this function twice on the boot CPU, once with a bogus timeout
921 * value, second time for real. The other (noncalibrating) CPUs
922 * call this function only once, with the real, calibrated value.
924 * We do reads before writes even if unnecessary, to get around the
925 * P5 APIC double write bug.
928 #define APIC_DIVISOR 16
930 static void __setup_APIC_LVTT(unsigned int clocks)
932 unsigned int lvtt_value, tmp_value, ver;
934 ver = GET_APIC_VERSION(apic_read(APIC_LVR));
935 lvtt_value = APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR;
936 if (!APIC_INTEGRATED(ver))
937 lvtt_value |= SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV);
938 apic_write_around(APIC_LVTT, lvtt_value);
943 tmp_value = apic_read(APIC_TDCR);
944 apic_write_around(APIC_TDCR, (tmp_value
945 & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE))
948 apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR);
951 static void __devinit setup_APIC_timer(unsigned int clocks)
955 local_irq_save(flags);
958 * Wait for IRQ0's slice:
962 __setup_APIC_LVTT(clocks);
964 local_irq_restore(flags);
968 * In this function we calibrate APIC bus clocks to the external
969 * timer. Unfortunately we cannot use jiffies and the timer irq
970 * to calibrate, since some later bootup code depends on getting
971 * the first irq? Ugh.
973 * We want to do the calibration only once since we
974 * want to have local timer irqs syncron. CPUs connected
975 * by the same APIC bus have the very same bus frequency.
976 * And we want to have irqs off anyways, no accidental
980 static int __init calibrate_APIC_clock(void)
982 unsigned long long t1 = 0, t2 = 0;
986 const int LOOPS = HZ/10;
988 apic_printk(APIC_VERBOSE, "calibrating APIC timer ...\n");
991 * Put whatever arbitrary (but long enough) timeout
992 * value into the APIC clock, we just want to get the
993 * counter running for calibration.
995 __setup_APIC_LVTT(1000000000);
998 * The timer chip counts down to zero. Let's wait
999 * for a wraparound to start exact measurement:
1000 * (the current tick might have been already half done)
1006 * We wrapped around just now. Let's start:
1010 tt1 = apic_read(APIC_TMCCT);
1013 * Let's wait LOOPS wraprounds:
1015 for (i = 0; i < LOOPS; i++)
1018 tt2 = apic_read(APIC_TMCCT);
1023 * The APIC bus clock counter is 32 bits only, it
1024 * might have overflown, but note that we use signed
1025 * longs, thus no extra care needed.
1027 * underflown to be exact, as the timer counts down ;)
1030 result = (tt1-tt2)*APIC_DIVISOR/LOOPS;
1033 apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
1035 ((long)(t2-t1)/LOOPS)/(1000000/HZ),
1036 ((long)(t2-t1)/LOOPS)%(1000000/HZ));
1038 apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
1040 result/(1000000/HZ),
1041 result%(1000000/HZ));
1046 static unsigned int calibration_result;
1048 void __init setup_boot_APIC_clock(void)
1050 apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n");
1051 using_apic_timer = 1;
1053 local_irq_disable();
1055 calibration_result = calibrate_APIC_clock();
1057 * Now set up the timer for real.
1059 setup_APIC_timer(calibration_result);
1064 void __devinit setup_secondary_APIC_clock(void)
1066 setup_APIC_timer(calibration_result);
1069 void __devinit disable_APIC_timer(void)
1071 if (using_apic_timer) {
1074 v = apic_read(APIC_LVTT);
1075 apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
1079 void enable_APIC_timer(void)
1081 if (using_apic_timer) {
1084 v = apic_read(APIC_LVTT);
1085 apic_write_around(APIC_LVTT, v & ~APIC_LVT_MASKED);
1090 * the frequency of the profiling timer can be changed
1091 * by writing a multiplier value into /proc/profile.
1093 int setup_profiling_timer(unsigned int multiplier)
1098 * Sanity check. [at least 500 APIC cycles should be
1099 * between APIC interrupts as a rule of thumb, to avoid
1102 if ( (!multiplier) || (calibration_result/multiplier < 500))
1106 * Set the new multiplier for each CPU. CPUs don't start using the
1107 * new values until the next timer interrupt in which they do process
1108 * accounting. At that time they also adjust their APIC timers
1111 for (i = 0; i < NR_CPUS; ++i)
1112 per_cpu(prof_multiplier, i) = multiplier;
1120 * Local timer interrupt handler. It does both profiling and
1121 * process statistics/rescheduling.
1123 * We do profiling in every local tick, statistics/rescheduling
1124 * happen only every 'profiling multiplier' ticks. The default
1125 * multiplier is 1 and it can be changed by writing the new multiplier
1126 * value into /proc/profile.
1129 inline void smp_local_timer_interrupt(struct pt_regs * regs)
1131 int cpu = smp_processor_id();
1133 profile_tick(CPU_PROFILING, regs);
1134 if (--per_cpu(prof_counter, cpu) <= 0) {
1136 * The multiplier may have changed since the last time we got
1137 * to this point as a result of the user writing to
1138 * /proc/profile. In this case we need to adjust the APIC
1139 * timer accordingly.
1141 * Interrupts are already masked off at this point.
1143 per_cpu(prof_counter, cpu) = per_cpu(prof_multiplier, cpu);
1144 if (per_cpu(prof_counter, cpu) !=
1145 per_cpu(prof_old_multiplier, cpu)) {
1148 per_cpu(prof_counter, cpu));
1149 per_cpu(prof_old_multiplier, cpu) =
1150 per_cpu(prof_counter, cpu);
1154 update_process_times(user_mode_vm(regs));
1159 * We take the 'long' return path, and there every subsystem
1160 * grabs the apropriate locks (kernel lock/ irq lock).
1162 * we might want to decouple profiling from the 'long path',
1163 * and do the profiling totally in assembly.
1165 * Currently this isn't too much of an issue (performance wise),
1166 * we can take more than 100K local irqs per second on a 100 MHz P5.
1171 * Local APIC timer interrupt. This is the most natural way for doing
1172 * local interrupts, but local timer interrupts can be emulated by
1173 * broadcast interrupts too. [in case the hw doesn't support APIC timers]
1175 * [ if a single-CPU system runs an SMP kernel then we call the local
1176 * interrupt as well. Thus we cannot inline the local irq ... ]
1179 fastcall void smp_apic_timer_interrupt(struct pt_regs *regs)
1181 int cpu = smp_processor_id();
1184 * the NMI deadlock-detector uses this.
1186 per_cpu(irq_stat, cpu).apic_timer_irqs++;
1189 * NOTE! We'd better ACK the irq immediately,
1190 * because timer handling can be slow.
1194 * update_process_times() expects us to have done irq_enter().
1195 * Besides, if we don't timer interrupts ignore the global
1196 * interrupt lock, which is the WrongThing (tm) to do.
1199 smp_local_timer_interrupt(regs);
1204 * This interrupt should _never_ happen with our APIC/SMP architecture
1206 fastcall void smp_spurious_interrupt(struct pt_regs *regs)
1212 * Check if this really is a spurious interrupt and ACK it
1213 * if it is a vectored one. Just in case...
1214 * Spurious interrupts should not be ACKed.
1216 v = apic_read(APIC_ISR + ((SPURIOUS_APIC_VECTOR & ~0x1f) >> 1));
1217 if (v & (1 << (SPURIOUS_APIC_VECTOR & 0x1f)))
1220 /* see sw-dev-man vol 3, chapter 7.4.13.5 */
1221 printk(KERN_INFO "spurious APIC interrupt on CPU#%d, should never happen.\n",
1222 smp_processor_id());
1227 * This interrupt should never happen with our APIC/SMP architecture
1230 fastcall void smp_error_interrupt(struct pt_regs *regs)
1232 unsigned long v, v1;
1235 /* First tickle the hardware, only then report what went on. -- REW */
1236 v = apic_read(APIC_ESR);
1237 apic_write(APIC_ESR, 0);
1238 v1 = apic_read(APIC_ESR);
1240 atomic_inc(&irq_err_count);
1242 /* Here is what the APIC error bits mean:
1245 2: Send accept error
1246 3: Receive accept error
1248 5: Send illegal vector
1249 6: Received illegal vector
1250 7: Illegal register address
1252 printk (KERN_DEBUG "APIC error on CPU%d: %02lx(%02lx)\n",
1253 smp_processor_id(), v , v1);
1258 * This initializes the IO-APIC and APIC hardware if this is
1261 int __init APIC_init_uniprocessor (void)
1263 if (enable_local_apic < 0)
1264 clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
1266 if (!smp_found_config && !cpu_has_apic)
1270 * Complain if the BIOS pretends there is one.
1272 if (!cpu_has_apic && APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
1273 printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
1274 boot_cpu_physical_apicid);
1278 verify_local_APIC();
1282 phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid);
1286 #ifdef CONFIG_X86_IO_APIC
1287 if (smp_found_config)
1288 if (!skip_ioapic_setup && nr_ioapics)
1291 setup_boot_APIC_clock();