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/delay.h>
22 #include <linux/bootmem.h>
23 #include <linux/smp_lock.h>
24 #include <linux/interrupt.h>
25 #include <linux/mc146818rtc.h>
26 #include <linux/kernel_stat.h>
27 #include <linux/sysdev.h>
28 #include <linux/cpu.h>
30 #include <asm/atomic.h>
33 #include <asm/mpspec.h>
35 #include <asm/arch_hooks.h>
37 #include <asm/i8253.h>
39 #include <mach_apic.h>
44 * Knob to control our willingness to enable the local APIC.
46 int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */
54 static void apic_pm_activate(void);
57 * 'what should we do if we get a hw irq event on an illegal vector'.
58 * each architecture has to answer this themselves.
60 void ack_bad_irq(unsigned int irq)
62 printk("unexpected IRQ trap at vector %02x\n", irq);
64 * Currently unexpected vectors happen only on SMP and APIC.
65 * We _must_ ack these because every local APIC has only N
66 * irq slots per priority level, and a 'hanging, unacked' IRQ
67 * holds up an irq slot - in excessive cases (when multiple
68 * unexpected vectors occur) that might lock up the APIC
74 void __init apic_intr_init(void)
79 /* self generated IPI for local APIC timer */
80 set_intr_gate(LOCAL_TIMER_VECTOR, apic_timer_interrupt);
82 /* IPI vectors for APIC spurious and error interrupts */
83 set_intr_gate(SPURIOUS_APIC_VECTOR, spurious_interrupt);
84 set_intr_gate(ERROR_APIC_VECTOR, error_interrupt);
86 /* thermal monitor LVT interrupt */
87 #ifdef CONFIG_X86_MCE_P4THERMAL
88 set_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt);
92 /* Using APIC to generate smp_local_timer_interrupt? */
93 int using_apic_timer = 0;
95 static DEFINE_PER_CPU(int, prof_multiplier) = 1;
96 static DEFINE_PER_CPU(int, prof_old_multiplier) = 1;
97 static DEFINE_PER_CPU(int, prof_counter) = 1;
99 static int enabled_via_apicbase;
101 void enable_NMI_through_LVT0 (void * dummy)
105 ver = apic_read(APIC_LVR);
106 ver = GET_APIC_VERSION(ver);
107 v = APIC_DM_NMI; /* unmask and set to NMI */
108 if (!APIC_INTEGRATED(ver)) /* 82489DX */
109 v |= APIC_LVT_LEVEL_TRIGGER;
110 apic_write_around(APIC_LVT0, v);
113 int get_physical_broadcast(void)
115 unsigned int lvr, version;
116 lvr = apic_read(APIC_LVR);
117 version = GET_APIC_VERSION(lvr);
118 if (!APIC_INTEGRATED(version) || version >= 0x14)
126 unsigned int v, ver, maxlvt;
128 v = apic_read(APIC_LVR);
129 ver = GET_APIC_VERSION(v);
130 /* 82489DXs do not report # of LVT entries. */
131 maxlvt = APIC_INTEGRATED(ver) ? GET_APIC_MAXLVT(v) : 2;
135 void clear_local_APIC(void)
140 maxlvt = get_maxlvt();
143 * Masking an LVT entry on a P6 can trigger a local APIC error
144 * if the vector is zero. Mask LVTERR first to prevent this.
147 v = ERROR_APIC_VECTOR; /* any non-zero vector will do */
148 apic_write_around(APIC_LVTERR, v | APIC_LVT_MASKED);
151 * Careful: we have to set masks only first to deassert
152 * any level-triggered sources.
154 v = apic_read(APIC_LVTT);
155 apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
156 v = apic_read(APIC_LVT0);
157 apic_write_around(APIC_LVT0, v | APIC_LVT_MASKED);
158 v = apic_read(APIC_LVT1);
159 apic_write_around(APIC_LVT1, v | APIC_LVT_MASKED);
161 v = apic_read(APIC_LVTPC);
162 apic_write_around(APIC_LVTPC, v | APIC_LVT_MASKED);
165 /* lets not touch this if we didn't frob it */
166 #ifdef CONFIG_X86_MCE_P4THERMAL
168 v = apic_read(APIC_LVTTHMR);
169 apic_write_around(APIC_LVTTHMR, v | APIC_LVT_MASKED);
173 * Clean APIC state for other OSs:
175 apic_write_around(APIC_LVTT, APIC_LVT_MASKED);
176 apic_write_around(APIC_LVT0, APIC_LVT_MASKED);
177 apic_write_around(APIC_LVT1, APIC_LVT_MASKED);
179 apic_write_around(APIC_LVTERR, APIC_LVT_MASKED);
181 apic_write_around(APIC_LVTPC, APIC_LVT_MASKED);
183 #ifdef CONFIG_X86_MCE_P4THERMAL
185 apic_write_around(APIC_LVTTHMR, APIC_LVT_MASKED);
187 v = GET_APIC_VERSION(apic_read(APIC_LVR));
188 if (APIC_INTEGRATED(v)) { /* !82489DX */
189 if (maxlvt > 3) /* Due to Pentium errata 3AP and 11AP. */
190 apic_write(APIC_ESR, 0);
195 void __init connect_bsp_APIC(void)
199 * Do not trust the local APIC being empty at bootup.
203 * PIC mode, enable APIC mode in the IMCR, i.e.
204 * connect BSP's local APIC to INT and NMI lines.
206 apic_printk(APIC_VERBOSE, "leaving PIC mode, "
207 "enabling APIC mode.\n");
214 void disconnect_bsp_APIC(int virt_wire_setup)
218 * Put the board back into PIC mode (has an effect
219 * only on certain older boards). Note that APIC
220 * interrupts, including IPIs, won't work beyond
221 * this point! The only exception are INIT IPIs.
223 apic_printk(APIC_VERBOSE, "disabling APIC mode, "
224 "entering PIC mode.\n");
229 /* Go back to Virtual Wire compatibility mode */
232 /* For the spurious interrupt use vector F, and enable it */
233 value = apic_read(APIC_SPIV);
234 value &= ~APIC_VECTOR_MASK;
235 value |= APIC_SPIV_APIC_ENABLED;
237 apic_write_around(APIC_SPIV, value);
239 if (!virt_wire_setup) {
240 /* For LVT0 make it edge triggered, active high, external and enabled */
241 value = apic_read(APIC_LVT0);
242 value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
243 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
244 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
245 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
246 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT);
247 apic_write_around(APIC_LVT0, value);
251 apic_write_around(APIC_LVT0, APIC_LVT_MASKED);
254 /* For LVT1 make it edge triggered, active high, nmi and enabled */
255 value = apic_read(APIC_LVT1);
257 APIC_MODE_MASK | APIC_SEND_PENDING |
258 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
259 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
260 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
261 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
262 apic_write_around(APIC_LVT1, value);
266 void disable_local_APIC(void)
273 * Disable APIC (implies clearing of registers
276 value = apic_read(APIC_SPIV);
277 value &= ~APIC_SPIV_APIC_ENABLED;
278 apic_write_around(APIC_SPIV, value);
280 if (enabled_via_apicbase) {
282 rdmsr(MSR_IA32_APICBASE, l, h);
283 l &= ~MSR_IA32_APICBASE_ENABLE;
284 wrmsr(MSR_IA32_APICBASE, l, h);
289 * This is to verify that we're looking at a real local APIC.
290 * Check these against your board if the CPUs aren't getting
291 * started for no apparent reason.
293 int __init verify_local_APIC(void)
295 unsigned int reg0, reg1;
298 * The version register is read-only in a real APIC.
300 reg0 = apic_read(APIC_LVR);
301 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg0);
302 apic_write(APIC_LVR, reg0 ^ APIC_LVR_MASK);
303 reg1 = apic_read(APIC_LVR);
304 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg1);
307 * The two version reads above should print the same
308 * numbers. If the second one is different, then we
309 * poke at a non-APIC.
315 * Check if the version looks reasonably.
317 reg1 = GET_APIC_VERSION(reg0);
318 if (reg1 == 0x00 || reg1 == 0xff)
321 if (reg1 < 0x02 || reg1 == 0xff)
325 * The ID register is read/write in a real APIC.
327 reg0 = apic_read(APIC_ID);
328 apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg0);
331 * The next two are just to see if we have sane values.
332 * They're only really relevant if we're in Virtual Wire
333 * compatibility mode, but most boxes are anymore.
335 reg0 = apic_read(APIC_LVT0);
336 apic_printk(APIC_DEBUG, "Getting LVT0: %x\n", reg0);
337 reg1 = apic_read(APIC_LVT1);
338 apic_printk(APIC_DEBUG, "Getting LVT1: %x\n", reg1);
343 void __init sync_Arb_IDs(void)
345 /* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 */
346 unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
347 if (ver >= 0x14) /* P4 or higher */
352 apic_wait_icr_idle();
354 apic_printk(APIC_DEBUG, "Synchronizing Arb IDs.\n");
355 apic_write_around(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG
359 extern void __error_in_apic_c (void);
362 * An initial setup of the virtual wire mode.
364 void __init init_bsp_APIC(void)
366 unsigned long value, ver;
369 * Don't do the setup now if we have a SMP BIOS as the
370 * through-I/O-APIC virtual wire mode might be active.
372 if (smp_found_config || !cpu_has_apic)
375 value = apic_read(APIC_LVR);
376 ver = GET_APIC_VERSION(value);
379 * Do not trust the local APIC being empty at bootup.
386 value = apic_read(APIC_SPIV);
387 value &= ~APIC_VECTOR_MASK;
388 value |= APIC_SPIV_APIC_ENABLED;
390 /* This bit is reserved on P4/Xeon and should be cleared */
391 if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 15))
392 value &= ~APIC_SPIV_FOCUS_DISABLED;
394 value |= APIC_SPIV_FOCUS_DISABLED;
395 value |= SPURIOUS_APIC_VECTOR;
396 apic_write_around(APIC_SPIV, value);
399 * Set up the virtual wire mode.
401 apic_write_around(APIC_LVT0, APIC_DM_EXTINT);
403 if (!APIC_INTEGRATED(ver)) /* 82489DX */
404 value |= APIC_LVT_LEVEL_TRIGGER;
405 apic_write_around(APIC_LVT1, value);
408 void __devinit setup_local_APIC(void)
410 unsigned long oldvalue, value, ver, maxlvt;
412 /* Pound the ESR really hard over the head with a big hammer - mbligh */
414 apic_write(APIC_ESR, 0);
415 apic_write(APIC_ESR, 0);
416 apic_write(APIC_ESR, 0);
417 apic_write(APIC_ESR, 0);
420 value = apic_read(APIC_LVR);
421 ver = GET_APIC_VERSION(value);
423 if ((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f)
427 * Double-check whether this APIC is really registered.
429 if (!apic_id_registered())
433 * Intel recommends to set DFR, LDR and TPR before enabling
434 * an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel
435 * document number 292116). So here it goes...
440 * Set Task Priority to 'accept all'. We never change this
443 value = apic_read(APIC_TASKPRI);
444 value &= ~APIC_TPRI_MASK;
445 apic_write_around(APIC_TASKPRI, value);
448 * Now that we are all set up, enable the APIC
450 value = apic_read(APIC_SPIV);
451 value &= ~APIC_VECTOR_MASK;
455 value |= APIC_SPIV_APIC_ENABLED;
458 * Some unknown Intel IO/APIC (or APIC) errata is biting us with
459 * certain networking cards. If high frequency interrupts are
460 * happening on a particular IOAPIC pin, plus the IOAPIC routing
461 * entry is masked/unmasked at a high rate as well then sooner or
462 * later IOAPIC line gets 'stuck', no more interrupts are received
463 * from the device. If focus CPU is disabled then the hang goes
466 * [ This bug can be reproduced easily with a level-triggered
467 * PCI Ne2000 networking cards and PII/PIII processors, dual
471 * Actually disabling the focus CPU check just makes the hang less
472 * frequent as it makes the interrupt distributon model be more
473 * like LRU than MRU (the short-term load is more even across CPUs).
474 * See also the comment in end_level_ioapic_irq(). --macro
477 /* Enable focus processor (bit==0) */
478 value &= ~APIC_SPIV_FOCUS_DISABLED;
480 /* Disable focus processor (bit==1) */
481 value |= APIC_SPIV_FOCUS_DISABLED;
484 * Set spurious IRQ vector
486 value |= SPURIOUS_APIC_VECTOR;
487 apic_write_around(APIC_SPIV, value);
492 * set up through-local-APIC on the BP's LINT0. This is not
493 * strictly necessery in pure symmetric-IO mode, but sometimes
494 * we delegate interrupts to the 8259A.
497 * TODO: set up through-local-APIC from through-I/O-APIC? --macro
499 value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
500 if (!smp_processor_id() && (pic_mode || !value)) {
501 value = APIC_DM_EXTINT;
502 apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n",
505 value = APIC_DM_EXTINT | APIC_LVT_MASKED;
506 apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n",
509 apic_write_around(APIC_LVT0, value);
512 * only the BP should see the LINT1 NMI signal, obviously.
514 if (!smp_processor_id())
517 value = APIC_DM_NMI | APIC_LVT_MASKED;
518 if (!APIC_INTEGRATED(ver)) /* 82489DX */
519 value |= APIC_LVT_LEVEL_TRIGGER;
520 apic_write_around(APIC_LVT1, value);
522 if (APIC_INTEGRATED(ver) && !esr_disable) { /* !82489DX */
523 maxlvt = get_maxlvt();
524 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
525 apic_write(APIC_ESR, 0);
526 oldvalue = apic_read(APIC_ESR);
528 value = ERROR_APIC_VECTOR; // enables sending errors
529 apic_write_around(APIC_LVTERR, value);
531 * spec says clear errors after enabling vector.
534 apic_write(APIC_ESR, 0);
535 value = apic_read(APIC_ESR);
536 if (value != oldvalue)
537 apic_printk(APIC_VERBOSE, "ESR value before enabling "
538 "vector: 0x%08lx after: 0x%08lx\n",
543 * Something untraceble is creating bad interrupts on
544 * secondary quads ... for the moment, just leave the
545 * ESR disabled - we can't do anything useful with the
546 * errors anyway - mbligh
548 printk("Leaving ESR disabled.\n");
550 printk("No ESR for 82489DX.\n");
553 if (nmi_watchdog == NMI_LOCAL_APIC)
554 setup_apic_nmi_watchdog();
559 * If Linux enabled the LAPIC against the BIOS default
560 * disable it down before re-entering the BIOS on shutdown.
561 * Otherwise the BIOS may get confused and not power-off.
563 void lapic_shutdown(void)
565 if (!cpu_has_apic || !enabled_via_apicbase)
569 disable_local_APIC();
577 /* r/w apic fields */
578 unsigned int apic_id;
579 unsigned int apic_taskpri;
580 unsigned int apic_ldr;
581 unsigned int apic_dfr;
582 unsigned int apic_spiv;
583 unsigned int apic_lvtt;
584 unsigned int apic_lvtpc;
585 unsigned int apic_lvt0;
586 unsigned int apic_lvt1;
587 unsigned int apic_lvterr;
588 unsigned int apic_tmict;
589 unsigned int apic_tdcr;
590 unsigned int apic_thmr;
593 static int lapic_suspend(struct sys_device *dev, pm_message_t state)
597 if (!apic_pm_state.active)
600 apic_pm_state.apic_id = apic_read(APIC_ID);
601 apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
602 apic_pm_state.apic_ldr = apic_read(APIC_LDR);
603 apic_pm_state.apic_dfr = apic_read(APIC_DFR);
604 apic_pm_state.apic_spiv = apic_read(APIC_SPIV);
605 apic_pm_state.apic_lvtt = apic_read(APIC_LVTT);
606 apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC);
607 apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0);
608 apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1);
609 apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
610 apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
611 apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
612 apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
614 local_irq_save(flags);
615 disable_local_APIC();
616 local_irq_restore(flags);
620 static int lapic_resume(struct sys_device *dev)
625 if (!apic_pm_state.active)
628 local_irq_save(flags);
631 * Make sure the APICBASE points to the right address
633 * FIXME! This will be wrong if we ever support suspend on
634 * SMP! We'll need to do this as part of the CPU restore!
636 rdmsr(MSR_IA32_APICBASE, l, h);
637 l &= ~MSR_IA32_APICBASE_BASE;
638 l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr;
639 wrmsr(MSR_IA32_APICBASE, l, h);
641 apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
642 apic_write(APIC_ID, apic_pm_state.apic_id);
643 apic_write(APIC_DFR, apic_pm_state.apic_dfr);
644 apic_write(APIC_LDR, apic_pm_state.apic_ldr);
645 apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri);
646 apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
647 apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
648 apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
649 apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr);
650 apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
651 apic_write(APIC_LVTT, apic_pm_state.apic_lvtt);
652 apic_write(APIC_TDCR, apic_pm_state.apic_tdcr);
653 apic_write(APIC_TMICT, apic_pm_state.apic_tmict);
654 apic_write(APIC_ESR, 0);
656 apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr);
657 apic_write(APIC_ESR, 0);
659 local_irq_restore(flags);
664 * This device has no shutdown method - fully functioning local APICs
665 * are needed on every CPU up until machine_halt/restart/poweroff.
668 static struct sysdev_class lapic_sysclass = {
669 set_kset_name("lapic"),
670 .resume = lapic_resume,
671 .suspend = lapic_suspend,
674 static struct sys_device device_lapic = {
676 .cls = &lapic_sysclass,
679 static void __devinit apic_pm_activate(void)
681 apic_pm_state.active = 1;
684 static int __init init_lapic_sysfs(void)
690 /* XXX: remove suspend/resume procs if !apic_pm_state.active? */
692 error = sysdev_class_register(&lapic_sysclass);
694 error = sysdev_register(&device_lapic);
697 device_initcall(init_lapic_sysfs);
699 #else /* CONFIG_PM */
701 static void apic_pm_activate(void) { }
703 #endif /* CONFIG_PM */
706 * Detect and enable local APICs on non-SMP boards.
707 * Original code written by Keir Fraser.
710 static int __init apic_set_verbosity(char *str)
712 if (strcmp("debug", str) == 0)
713 apic_verbosity = APIC_DEBUG;
714 else if (strcmp("verbose", str) == 0)
715 apic_verbosity = APIC_VERBOSE;
717 printk(KERN_WARNING "APIC Verbosity level %s not recognised"
718 " use apic=verbose or apic=debug", str);
723 __setup("apic=", apic_set_verbosity);
725 static int __init detect_init_APIC (void)
729 /* Disabled by kernel option? */
730 if (enable_local_apic < 0)
733 switch (boot_cpu_data.x86_vendor) {
735 if ((boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model > 1) ||
736 (boot_cpu_data.x86 == 15))
739 case X86_VENDOR_INTEL:
740 if (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15 ||
741 (boot_cpu_data.x86 == 5 && cpu_has_apic))
750 * Over-ride BIOS and try to enable the local
751 * APIC only if "lapic" specified.
753 if (enable_local_apic <= 0) {
754 printk("Local APIC disabled by BIOS -- "
755 "you can enable it with \"lapic\"\n");
759 * Some BIOSes disable the local APIC in the
760 * APIC_BASE MSR. This can only be done in
761 * software for Intel P6 or later and AMD K7
762 * (Model > 1) or later.
764 rdmsr(MSR_IA32_APICBASE, l, h);
765 if (!(l & MSR_IA32_APICBASE_ENABLE)) {
766 printk("Local APIC disabled by BIOS -- reenabling.\n");
767 l &= ~MSR_IA32_APICBASE_BASE;
768 l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
769 wrmsr(MSR_IA32_APICBASE, l, h);
770 enabled_via_apicbase = 1;
774 * The APIC feature bit should now be enabled
777 features = cpuid_edx(1);
778 if (!(features & (1 << X86_FEATURE_APIC))) {
779 printk("Could not enable APIC!\n");
782 set_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
783 mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
785 /* The BIOS may have set up the APIC at some other address */
786 rdmsr(MSR_IA32_APICBASE, l, h);
787 if (l & MSR_IA32_APICBASE_ENABLE)
788 mp_lapic_addr = l & MSR_IA32_APICBASE_BASE;
790 if (nmi_watchdog != NMI_NONE)
791 nmi_watchdog = NMI_LOCAL_APIC;
793 printk("Found and enabled local APIC!\n");
800 printk("No local APIC present or hardware disabled\n");
804 void __init init_apic_mappings(void)
806 unsigned long apic_phys;
809 * If no local APIC can be found then set up a fake all
810 * zeroes page to simulate the local APIC and another
811 * one for the IO-APIC.
813 if (!smp_found_config && detect_init_APIC()) {
814 apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
815 apic_phys = __pa(apic_phys);
817 apic_phys = mp_lapic_addr;
819 set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
820 printk(KERN_DEBUG "mapped APIC to %08lx (%08lx)\n", APIC_BASE,
824 * Fetch the APIC ID of the BSP in case we have a
825 * default configuration (or the MP table is broken).
827 if (boot_cpu_physical_apicid == -1U)
828 boot_cpu_physical_apicid = GET_APIC_ID(apic_read(APIC_ID));
830 #ifdef CONFIG_X86_IO_APIC
832 unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
835 for (i = 0; i < nr_ioapics; i++) {
836 if (smp_found_config) {
837 ioapic_phys = mp_ioapics[i].mpc_apicaddr;
840 "WARNING: bogus zero IO-APIC "
841 "address found in MPTABLE, "
842 "disabling IO/APIC support!\n");
843 smp_found_config = 0;
844 skip_ioapic_setup = 1;
845 goto fake_ioapic_page;
849 ioapic_phys = (unsigned long)
850 alloc_bootmem_pages(PAGE_SIZE);
851 ioapic_phys = __pa(ioapic_phys);
853 set_fixmap_nocache(idx, ioapic_phys);
854 printk(KERN_DEBUG "mapped IOAPIC to %08lx (%08lx)\n",
855 __fix_to_virt(idx), ioapic_phys);
863 * This part sets up the APIC 32 bit clock in LVTT1, with HZ interrupts
864 * per second. We assume that the caller has already set up the local
867 * The APIC timer is not exactly sync with the external timer chip, it
868 * closely follows bus clocks.
872 * The timer chip is already set up at HZ interrupts per second here,
873 * but we do not accept timer interrupts yet. We only allow the BP
876 static unsigned int __devinit get_8254_timer_count(void)
882 spin_lock_irqsave(&i8253_lock, flags);
884 outb_p(0x00, PIT_MODE);
885 count = inb_p(PIT_CH0);
886 count |= inb_p(PIT_CH0) << 8;
888 spin_unlock_irqrestore(&i8253_lock, flags);
893 /* next tick in 8254 can be caught by catching timer wraparound */
894 static void __devinit wait_8254_wraparound(void)
896 unsigned int curr_count, prev_count;
898 curr_count = get_8254_timer_count();
900 prev_count = curr_count;
901 curr_count = get_8254_timer_count();
903 /* workaround for broken Mercury/Neptune */
904 if (prev_count >= curr_count + 0x100)
905 curr_count = get_8254_timer_count();
907 } while (prev_count >= curr_count);
911 * Default initialization for 8254 timers. If we use other timers like HPET,
912 * we override this later
914 void (*wait_timer_tick)(void) __devinitdata = wait_8254_wraparound;
917 * This function sets up the local APIC timer, with a timeout of
918 * 'clocks' APIC bus clock. During calibration we actually call
919 * this function twice on the boot CPU, once with a bogus timeout
920 * value, second time for real. The other (noncalibrating) CPUs
921 * call this function only once, with the real, calibrated value.
923 * We do reads before writes even if unnecessary, to get around the
924 * P5 APIC double write bug.
927 #define APIC_DIVISOR 16
929 static void __setup_APIC_LVTT(unsigned int clocks)
931 unsigned int lvtt_value, tmp_value, ver;
933 ver = GET_APIC_VERSION(apic_read(APIC_LVR));
934 lvtt_value = APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR;
935 if (!APIC_INTEGRATED(ver))
936 lvtt_value |= SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV);
937 apic_write_around(APIC_LVTT, lvtt_value);
942 tmp_value = apic_read(APIC_TDCR);
943 apic_write_around(APIC_TDCR, (tmp_value
944 & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE))
947 apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR);
950 static void __devinit setup_APIC_timer(unsigned int clocks)
954 local_irq_save(flags);
957 * Wait for IRQ0's slice:
961 __setup_APIC_LVTT(clocks);
963 local_irq_restore(flags);
967 * In this function we calibrate APIC bus clocks to the external
968 * timer. Unfortunately we cannot use jiffies and the timer irq
969 * to calibrate, since some later bootup code depends on getting
970 * the first irq? Ugh.
972 * We want to do the calibration only once since we
973 * want to have local timer irqs syncron. CPUs connected
974 * by the same APIC bus have the very same bus frequency.
975 * And we want to have irqs off anyways, no accidental
979 static int __init calibrate_APIC_clock(void)
981 unsigned long long t1 = 0, t2 = 0;
985 const int LOOPS = HZ/10;
987 apic_printk(APIC_VERBOSE, "calibrating APIC timer ...\n");
990 * Put whatever arbitrary (but long enough) timeout
991 * value into the APIC clock, we just want to get the
992 * counter running for calibration.
994 __setup_APIC_LVTT(1000000000);
997 * The timer chip counts down to zero. Let's wait
998 * for a wraparound to start exact measurement:
999 * (the current tick might have been already half done)
1005 * We wrapped around just now. Let's start:
1009 tt1 = apic_read(APIC_TMCCT);
1012 * Let's wait LOOPS wraprounds:
1014 for (i = 0; i < LOOPS; i++)
1017 tt2 = apic_read(APIC_TMCCT);
1022 * The APIC bus clock counter is 32 bits only, it
1023 * might have overflown, but note that we use signed
1024 * longs, thus no extra care needed.
1026 * underflown to be exact, as the timer counts down ;)
1029 result = (tt1-tt2)*APIC_DIVISOR/LOOPS;
1032 apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
1034 ((long)(t2-t1)/LOOPS)/(1000000/HZ),
1035 ((long)(t2-t1)/LOOPS)%(1000000/HZ));
1037 apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
1039 result/(1000000/HZ),
1040 result%(1000000/HZ));
1045 static unsigned int calibration_result;
1047 void __init setup_boot_APIC_clock(void)
1049 apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n");
1050 using_apic_timer = 1;
1052 local_irq_disable();
1054 calibration_result = calibrate_APIC_clock();
1056 * Now set up the timer for real.
1058 setup_APIC_timer(calibration_result);
1063 void __devinit setup_secondary_APIC_clock(void)
1065 setup_APIC_timer(calibration_result);
1068 void __devinit disable_APIC_timer(void)
1070 if (using_apic_timer) {
1073 v = apic_read(APIC_LVTT);
1074 apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
1078 void enable_APIC_timer(void)
1080 if (using_apic_timer) {
1083 v = apic_read(APIC_LVTT);
1084 apic_write_around(APIC_LVTT, v & ~APIC_LVT_MASKED);
1089 * the frequency of the profiling timer can be changed
1090 * by writing a multiplier value into /proc/profile.
1092 int setup_profiling_timer(unsigned int multiplier)
1097 * Sanity check. [at least 500 APIC cycles should be
1098 * between APIC interrupts as a rule of thumb, to avoid
1101 if ( (!multiplier) || (calibration_result/multiplier < 500))
1105 * Set the new multiplier for each CPU. CPUs don't start using the
1106 * new values until the next timer interrupt in which they do process
1107 * accounting. At that time they also adjust their APIC timers
1110 for (i = 0; i < NR_CPUS; ++i)
1111 per_cpu(prof_multiplier, i) = multiplier;
1119 * Local timer interrupt handler. It does both profiling and
1120 * process statistics/rescheduling.
1122 * We do profiling in every local tick, statistics/rescheduling
1123 * happen only every 'profiling multiplier' ticks. The default
1124 * multiplier is 1 and it can be changed by writing the new multiplier
1125 * value into /proc/profile.
1128 inline void smp_local_timer_interrupt(struct pt_regs * regs)
1130 int cpu = smp_processor_id();
1132 profile_tick(CPU_PROFILING, regs);
1133 if (--per_cpu(prof_counter, cpu) <= 0) {
1135 * The multiplier may have changed since the last time we got
1136 * to this point as a result of the user writing to
1137 * /proc/profile. In this case we need to adjust the APIC
1138 * timer accordingly.
1140 * Interrupts are already masked off at this point.
1142 per_cpu(prof_counter, cpu) = per_cpu(prof_multiplier, cpu);
1143 if (per_cpu(prof_counter, cpu) !=
1144 per_cpu(prof_old_multiplier, cpu)) {
1147 per_cpu(prof_counter, cpu));
1148 per_cpu(prof_old_multiplier, cpu) =
1149 per_cpu(prof_counter, cpu);
1153 update_process_times(user_mode_vm(regs));
1158 * We take the 'long' return path, and there every subsystem
1159 * grabs the apropriate locks (kernel lock/ irq lock).
1161 * we might want to decouple profiling from the 'long path',
1162 * and do the profiling totally in assembly.
1164 * Currently this isn't too much of an issue (performance wise),
1165 * we can take more than 100K local irqs per second on a 100 MHz P5.
1170 * Local APIC timer interrupt. This is the most natural way for doing
1171 * local interrupts, but local timer interrupts can be emulated by
1172 * broadcast interrupts too. [in case the hw doesn't support APIC timers]
1174 * [ if a single-CPU system runs an SMP kernel then we call the local
1175 * interrupt as well. Thus we cannot inline the local irq ... ]
1178 fastcall void smp_apic_timer_interrupt(struct pt_regs *regs)
1180 int cpu = smp_processor_id();
1183 * the NMI deadlock-detector uses this.
1185 per_cpu(irq_stat, cpu).apic_timer_irqs++;
1188 * NOTE! We'd better ACK the irq immediately,
1189 * because timer handling can be slow.
1193 * update_process_times() expects us to have done irq_enter().
1194 * Besides, if we don't timer interrupts ignore the global
1195 * interrupt lock, which is the WrongThing (tm) to do.
1198 smp_local_timer_interrupt(regs);
1203 * This interrupt should _never_ happen with our APIC/SMP architecture
1205 fastcall void smp_spurious_interrupt(struct pt_regs *regs)
1211 * Check if this really is a spurious interrupt and ACK it
1212 * if it is a vectored one. Just in case...
1213 * Spurious interrupts should not be ACKed.
1215 v = apic_read(APIC_ISR + ((SPURIOUS_APIC_VECTOR & ~0x1f) >> 1));
1216 if (v & (1 << (SPURIOUS_APIC_VECTOR & 0x1f)))
1219 /* see sw-dev-man vol 3, chapter 7.4.13.5 */
1220 printk(KERN_INFO "spurious APIC interrupt on CPU#%d, should never happen.\n",
1221 smp_processor_id());
1226 * This interrupt should never happen with our APIC/SMP architecture
1229 fastcall void smp_error_interrupt(struct pt_regs *regs)
1231 unsigned long v, v1;
1234 /* First tickle the hardware, only then report what went on. -- REW */
1235 v = apic_read(APIC_ESR);
1236 apic_write(APIC_ESR, 0);
1237 v1 = apic_read(APIC_ESR);
1239 atomic_inc(&irq_err_count);
1241 /* Here is what the APIC error bits mean:
1244 2: Send accept error
1245 3: Receive accept error
1247 5: Send illegal vector
1248 6: Received illegal vector
1249 7: Illegal register address
1251 printk (KERN_DEBUG "APIC error on CPU%d: %02lx(%02lx)\n",
1252 smp_processor_id(), v , v1);
1257 * This initializes the IO-APIC and APIC hardware if this is
1260 int __init APIC_init_uniprocessor (void)
1262 if (enable_local_apic < 0)
1263 clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
1265 if (!smp_found_config && !cpu_has_apic)
1269 * Complain if the BIOS pretends there is one.
1271 if (!cpu_has_apic && APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
1272 printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
1273 boot_cpu_physical_apicid);
1277 verify_local_APIC();
1281 phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid);
1285 #ifdef CONFIG_X86_IO_APIC
1286 if (smp_found_config)
1287 if (!skip_ioapic_setup && nr_ioapics)
1290 setup_boot_APIC_clock();