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>
35 #include <asm/arch_hooks.h>
38 #include <mach_apic.h>
48 static void apic_pm_activate(void);
51 * 'what should we do if we get a hw irq event on an illegal vector'.
52 * each architecture has to answer this themselves.
54 void ack_bad_irq(unsigned int irq)
56 printk("unexpected IRQ trap at vector %02x\n", irq);
58 * Currently unexpected vectors happen only on SMP and APIC.
59 * We _must_ ack these because every local APIC has only N
60 * irq slots per priority level, and a 'hanging, unacked' IRQ
61 * holds up an irq slot - in excessive cases (when multiple
62 * unexpected vectors occur) that might lock up the APIC
68 void __init apic_intr_init(void)
73 /* self generated IPI for local APIC timer */
74 set_intr_gate(LOCAL_TIMER_VECTOR, apic_timer_interrupt);
76 /* IPI vectors for APIC spurious and error interrupts */
77 set_intr_gate(SPURIOUS_APIC_VECTOR, spurious_interrupt);
78 set_intr_gate(ERROR_APIC_VECTOR, error_interrupt);
80 /* thermal monitor LVT interrupt */
81 #ifdef CONFIG_X86_MCE_P4THERMAL
82 set_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt);
86 /* Using APIC to generate smp_local_timer_interrupt? */
87 int using_apic_timer = 0;
89 static DEFINE_PER_CPU(int, prof_multiplier) = 1;
90 static DEFINE_PER_CPU(int, prof_old_multiplier) = 1;
91 static DEFINE_PER_CPU(int, prof_counter) = 1;
93 static int enabled_via_apicbase;
95 void enable_NMI_through_LVT0 (void * dummy)
99 ver = apic_read(APIC_LVR);
100 ver = GET_APIC_VERSION(ver);
101 v = APIC_DM_NMI; /* unmask and set to NMI */
102 if (!APIC_INTEGRATED(ver)) /* 82489DX */
103 v |= APIC_LVT_LEVEL_TRIGGER;
104 apic_write_around(APIC_LVT0, v);
107 int get_physical_broadcast(void)
109 unsigned int lvr, version;
110 lvr = apic_read(APIC_LVR);
111 version = GET_APIC_VERSION(lvr);
112 if (!APIC_INTEGRATED(version) || version >= 0x14)
120 unsigned int v, ver, maxlvt;
122 v = apic_read(APIC_LVR);
123 ver = GET_APIC_VERSION(v);
124 /* 82489DXs do not report # of LVT entries. */
125 maxlvt = APIC_INTEGRATED(ver) ? GET_APIC_MAXLVT(v) : 2;
129 void clear_local_APIC(void)
134 maxlvt = get_maxlvt();
137 * Masking an LVT entry on a P6 can trigger a local APIC error
138 * if the vector is zero. Mask LVTERR first to prevent this.
141 v = ERROR_APIC_VECTOR; /* any non-zero vector will do */
142 apic_write_around(APIC_LVTERR, v | APIC_LVT_MASKED);
145 * Careful: we have to set masks only first to deassert
146 * any level-triggered sources.
148 v = apic_read(APIC_LVTT);
149 apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
150 v = apic_read(APIC_LVT0);
151 apic_write_around(APIC_LVT0, v | APIC_LVT_MASKED);
152 v = apic_read(APIC_LVT1);
153 apic_write_around(APIC_LVT1, v | APIC_LVT_MASKED);
155 v = apic_read(APIC_LVTPC);
156 apic_write_around(APIC_LVTPC, v | APIC_LVT_MASKED);
159 /* lets not touch this if we didn't frob it */
160 #ifdef CONFIG_X86_MCE_P4THERMAL
162 v = apic_read(APIC_LVTTHMR);
163 apic_write_around(APIC_LVTTHMR, v | APIC_LVT_MASKED);
167 * Clean APIC state for other OSs:
169 apic_write_around(APIC_LVTT, APIC_LVT_MASKED);
170 apic_write_around(APIC_LVT0, APIC_LVT_MASKED);
171 apic_write_around(APIC_LVT1, APIC_LVT_MASKED);
173 apic_write_around(APIC_LVTERR, APIC_LVT_MASKED);
175 apic_write_around(APIC_LVTPC, APIC_LVT_MASKED);
177 #ifdef CONFIG_X86_MCE_P4THERMAL
179 apic_write_around(APIC_LVTTHMR, APIC_LVT_MASKED);
181 v = GET_APIC_VERSION(apic_read(APIC_LVR));
182 if (APIC_INTEGRATED(v)) { /* !82489DX */
183 if (maxlvt > 3) /* Due to Pentium errata 3AP and 11AP. */
184 apic_write(APIC_ESR, 0);
189 void __init connect_bsp_APIC(void)
193 * Do not trust the local APIC being empty at bootup.
197 * PIC mode, enable APIC mode in the IMCR, i.e.
198 * connect BSP's local APIC to INT and NMI lines.
200 apic_printk(APIC_VERBOSE, "leaving PIC mode, "
201 "enabling APIC mode.\n");
208 void disconnect_bsp_APIC(void)
212 * Put the board back into PIC mode (has an effect
213 * only on certain older boards). Note that APIC
214 * interrupts, including IPIs, won't work beyond
215 * this point! The only exception are INIT IPIs.
217 apic_printk(APIC_VERBOSE, "disabling APIC mode, "
218 "entering PIC mode.\n");
223 /* Go back to Virtual Wire compatibility mode */
226 /* For the spurious interrupt use vector F, and enable it */
227 value = apic_read(APIC_SPIV);
228 value &= ~APIC_VECTOR_MASK;
229 value |= APIC_SPIV_APIC_ENABLED;
231 apic_write_around(APIC_SPIV, value);
233 /* For LVT0 make it edge triggered, active high, external and enabled */
234 value = apic_read(APIC_LVT0);
235 value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
236 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
237 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED );
238 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
239 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXINT);
240 apic_write_around(APIC_LVT0, value);
242 /* For LVT1 make it edge triggered, active high, nmi and enabled */
243 value = apic_read(APIC_LVT1);
245 APIC_MODE_MASK | APIC_SEND_PENDING |
246 APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
247 APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
248 value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
249 value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
250 apic_write_around(APIC_LVT1, value);
254 void disable_local_APIC(void)
261 * Disable APIC (implies clearing of registers
264 value = apic_read(APIC_SPIV);
265 value &= ~APIC_SPIV_APIC_ENABLED;
266 apic_write_around(APIC_SPIV, value);
268 if (enabled_via_apicbase) {
270 rdmsr(MSR_IA32_APICBASE, l, h);
271 l &= ~MSR_IA32_APICBASE_ENABLE;
272 wrmsr(MSR_IA32_APICBASE, l, h);
277 * This is to verify that we're looking at a real local APIC.
278 * Check these against your board if the CPUs aren't getting
279 * started for no apparent reason.
281 int __init verify_local_APIC(void)
283 unsigned int reg0, reg1;
286 * The version register is read-only in a real APIC.
288 reg0 = apic_read(APIC_LVR);
289 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg0);
290 apic_write(APIC_LVR, reg0 ^ APIC_LVR_MASK);
291 reg1 = apic_read(APIC_LVR);
292 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg1);
295 * The two version reads above should print the same
296 * numbers. If the second one is different, then we
297 * poke at a non-APIC.
303 * Check if the version looks reasonably.
305 reg1 = GET_APIC_VERSION(reg0);
306 if (reg1 == 0x00 || reg1 == 0xff)
309 if (reg1 < 0x02 || reg1 == 0xff)
313 * The ID register is read/write in a real APIC.
315 reg0 = apic_read(APIC_ID);
316 apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg0);
319 * The next two are just to see if we have sane values.
320 * They're only really relevant if we're in Virtual Wire
321 * compatibility mode, but most boxes are anymore.
323 reg0 = apic_read(APIC_LVT0);
324 apic_printk(APIC_DEBUG, "Getting LVT0: %x\n", reg0);
325 reg1 = apic_read(APIC_LVT1);
326 apic_printk(APIC_DEBUG, "Getting LVT1: %x\n", reg1);
331 void __init sync_Arb_IDs(void)
333 /* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 */
334 unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
335 if (ver >= 0x14) /* P4 or higher */
340 apic_wait_icr_idle();
342 apic_printk(APIC_DEBUG, "Synchronizing Arb IDs.\n");
343 apic_write_around(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG
347 extern void __error_in_apic_c (void);
350 * An initial setup of the virtual wire mode.
352 void __init init_bsp_APIC(void)
354 unsigned long value, ver;
357 * Don't do the setup now if we have a SMP BIOS as the
358 * through-I/O-APIC virtual wire mode might be active.
360 if (smp_found_config || !cpu_has_apic)
363 value = apic_read(APIC_LVR);
364 ver = GET_APIC_VERSION(value);
367 * Do not trust the local APIC being empty at bootup.
374 value = apic_read(APIC_SPIV);
375 value &= ~APIC_VECTOR_MASK;
376 value |= APIC_SPIV_APIC_ENABLED;
378 /* This bit is reserved on P4/Xeon and should be cleared */
379 if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 15))
380 value &= ~APIC_SPIV_FOCUS_DISABLED;
382 value |= APIC_SPIV_FOCUS_DISABLED;
383 value |= SPURIOUS_APIC_VECTOR;
384 apic_write_around(APIC_SPIV, value);
387 * Set up the virtual wire mode.
389 apic_write_around(APIC_LVT0, APIC_DM_EXTINT);
391 if (!APIC_INTEGRATED(ver)) /* 82489DX */
392 value |= APIC_LVT_LEVEL_TRIGGER;
393 apic_write_around(APIC_LVT1, value);
396 void __init setup_local_APIC (void)
398 unsigned long oldvalue, value, ver, maxlvt;
400 /* Pound the ESR really hard over the head with a big hammer - mbligh */
402 apic_write(APIC_ESR, 0);
403 apic_write(APIC_ESR, 0);
404 apic_write(APIC_ESR, 0);
405 apic_write(APIC_ESR, 0);
408 value = apic_read(APIC_LVR);
409 ver = GET_APIC_VERSION(value);
411 if ((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f)
415 * Double-check whether this APIC is really registered.
417 if (!apic_id_registered())
421 * Intel recommends to set DFR, LDR and TPR before enabling
422 * an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel
423 * document number 292116). So here it goes...
428 * Set Task Priority to 'accept all'. We never change this
431 value = apic_read(APIC_TASKPRI);
432 value &= ~APIC_TPRI_MASK;
433 apic_write_around(APIC_TASKPRI, value);
436 * Now that we are all set up, enable the APIC
438 value = apic_read(APIC_SPIV);
439 value &= ~APIC_VECTOR_MASK;
443 value |= APIC_SPIV_APIC_ENABLED;
446 * Some unknown Intel IO/APIC (or APIC) errata is biting us with
447 * certain networking cards. If high frequency interrupts are
448 * happening on a particular IOAPIC pin, plus the IOAPIC routing
449 * entry is masked/unmasked at a high rate as well then sooner or
450 * later IOAPIC line gets 'stuck', no more interrupts are received
451 * from the device. If focus CPU is disabled then the hang goes
454 * [ This bug can be reproduced easily with a level-triggered
455 * PCI Ne2000 networking cards and PII/PIII processors, dual
459 * Actually disabling the focus CPU check just makes the hang less
460 * frequent as it makes the interrupt distributon model be more
461 * like LRU than MRU (the short-term load is more even across CPUs).
462 * See also the comment in end_level_ioapic_irq(). --macro
465 /* Enable focus processor (bit==0) */
466 value &= ~APIC_SPIV_FOCUS_DISABLED;
468 /* Disable focus processor (bit==1) */
469 value |= APIC_SPIV_FOCUS_DISABLED;
472 * Set spurious IRQ vector
474 value |= SPURIOUS_APIC_VECTOR;
475 apic_write_around(APIC_SPIV, value);
480 * set up through-local-APIC on the BP's LINT0. This is not
481 * strictly necessery in pure symmetric-IO mode, but sometimes
482 * we delegate interrupts to the 8259A.
485 * TODO: set up through-local-APIC from through-I/O-APIC? --macro
487 value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
488 if (!smp_processor_id() && (pic_mode || !value)) {
489 value = APIC_DM_EXTINT;
490 apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n",
493 value = APIC_DM_EXTINT | APIC_LVT_MASKED;
494 apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n",
497 apic_write_around(APIC_LVT0, value);
500 * only the BP should see the LINT1 NMI signal, obviously.
502 if (!smp_processor_id())
505 value = APIC_DM_NMI | APIC_LVT_MASKED;
506 if (!APIC_INTEGRATED(ver)) /* 82489DX */
507 value |= APIC_LVT_LEVEL_TRIGGER;
508 apic_write_around(APIC_LVT1, value);
510 if (APIC_INTEGRATED(ver) && !esr_disable) { /* !82489DX */
511 maxlvt = get_maxlvt();
512 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
513 apic_write(APIC_ESR, 0);
514 oldvalue = apic_read(APIC_ESR);
516 value = ERROR_APIC_VECTOR; // enables sending errors
517 apic_write_around(APIC_LVTERR, value);
519 * spec says clear errors after enabling vector.
522 apic_write(APIC_ESR, 0);
523 value = apic_read(APIC_ESR);
524 if (value != oldvalue)
525 apic_printk(APIC_VERBOSE, "ESR value before enabling "
526 "vector: 0x%08lx after: 0x%08lx\n",
531 * Something untraceble is creating bad interrupts on
532 * secondary quads ... for the moment, just leave the
533 * ESR disabled - we can't do anything useful with the
534 * errors anyway - mbligh
536 printk("Leaving ESR disabled.\n");
538 printk("No ESR for 82489DX.\n");
541 if (nmi_watchdog == NMI_LOCAL_APIC)
542 setup_apic_nmi_watchdog();
547 * If Linux enabled the LAPIC against the BIOS default
548 * disable it down before re-entering the BIOS on shutdown.
549 * Otherwise the BIOS may get confused and not power-off.
554 if (!cpu_has_apic || !enabled_via_apicbase)
558 disable_local_APIC();
566 /* r/w apic fields */
567 unsigned int apic_id;
568 unsigned int apic_taskpri;
569 unsigned int apic_ldr;
570 unsigned int apic_dfr;
571 unsigned int apic_spiv;
572 unsigned int apic_lvtt;
573 unsigned int apic_lvtpc;
574 unsigned int apic_lvt0;
575 unsigned int apic_lvt1;
576 unsigned int apic_lvterr;
577 unsigned int apic_tmict;
578 unsigned int apic_tdcr;
579 unsigned int apic_thmr;
582 static int lapic_suspend(struct sys_device *dev, u32 state)
586 if (!apic_pm_state.active)
589 apic_pm_state.apic_id = apic_read(APIC_ID);
590 apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
591 apic_pm_state.apic_ldr = apic_read(APIC_LDR);
592 apic_pm_state.apic_dfr = apic_read(APIC_DFR);
593 apic_pm_state.apic_spiv = apic_read(APIC_SPIV);
594 apic_pm_state.apic_lvtt = apic_read(APIC_LVTT);
595 apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC);
596 apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0);
597 apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1);
598 apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
599 apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
600 apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
601 apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
603 local_irq_save(flags);
604 disable_local_APIC();
605 local_irq_restore(flags);
609 static int lapic_resume(struct sys_device *dev)
614 if (!apic_pm_state.active)
617 local_irq_save(flags);
620 * Make sure the APICBASE points to the right address
622 * FIXME! This will be wrong if we ever support suspend on
623 * SMP! We'll need to do this as part of the CPU restore!
625 rdmsr(MSR_IA32_APICBASE, l, h);
626 l &= ~MSR_IA32_APICBASE_BASE;
627 l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr;
628 wrmsr(MSR_IA32_APICBASE, l, h);
630 apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
631 apic_write(APIC_ID, apic_pm_state.apic_id);
632 apic_write(APIC_DFR, apic_pm_state.apic_dfr);
633 apic_write(APIC_LDR, apic_pm_state.apic_ldr);
634 apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri);
635 apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
636 apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
637 apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
638 apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr);
639 apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
640 apic_write(APIC_LVTT, apic_pm_state.apic_lvtt);
641 apic_write(APIC_TDCR, apic_pm_state.apic_tdcr);
642 apic_write(APIC_TMICT, apic_pm_state.apic_tmict);
643 apic_write(APIC_ESR, 0);
645 apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr);
646 apic_write(APIC_ESR, 0);
648 local_irq_restore(flags);
653 * This device has no shutdown method - fully functioning local APICs
654 * are needed on every CPU up until machine_halt/restart/poweroff.
657 static struct sysdev_class lapic_sysclass = {
658 set_kset_name("lapic"),
659 .resume = lapic_resume,
660 .suspend = lapic_suspend,
663 static struct sys_device device_lapic = {
665 .cls = &lapic_sysclass,
668 static void __init apic_pm_activate(void)
670 apic_pm_state.active = 1;
673 static int __init init_lapic_sysfs(void)
679 /* XXX: remove suspend/resume procs if !apic_pm_state.active? */
681 error = sysdev_class_register(&lapic_sysclass);
683 error = sysdev_register(&device_lapic);
686 device_initcall(init_lapic_sysfs);
688 #else /* CONFIG_PM */
690 static void apic_pm_activate(void) { }
692 #endif /* CONFIG_PM */
695 * Detect and enable local APICs on non-SMP boards.
696 * Original code written by Keir Fraser.
700 * Knob to control our willingness to enable the local APIC.
702 int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */
704 static int __init lapic_disable(char *str)
706 enable_local_apic = -1;
707 clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
710 __setup("nolapic", lapic_disable);
712 static int __init lapic_enable(char *str)
714 enable_local_apic = 1;
717 __setup("lapic", lapic_enable);
719 static int __init apic_set_verbosity(char *str)
721 if (strcmp("debug", str) == 0)
722 apic_verbosity = APIC_DEBUG;
723 else if (strcmp("verbose", str) == 0)
724 apic_verbosity = APIC_VERBOSE;
726 printk(KERN_WARNING "APIC Verbosity level %s not recognised"
727 " use apic=verbose or apic=debug", str);
732 __setup("apic=", apic_set_verbosity);
734 static int __init detect_init_APIC (void)
737 extern void get_cpu_vendor(struct cpuinfo_x86*);
739 /* Disabled by kernel option? */
740 if (enable_local_apic < 0)
743 /* Workaround for us being called before identify_cpu(). */
744 get_cpu_vendor(&boot_cpu_data);
746 switch (boot_cpu_data.x86_vendor) {
748 if ((boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model > 1) ||
749 (boot_cpu_data.x86 == 15))
752 case X86_VENDOR_INTEL:
753 if (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15 ||
754 (boot_cpu_data.x86 == 5 && cpu_has_apic))
763 * Over-ride BIOS and try to enable the local
764 * APIC only if "lapic" specified.
766 if (enable_local_apic <= 0) {
767 printk("Local APIC disabled by BIOS -- "
768 "you can enable it with \"lapic\"\n");
772 * Some BIOSes disable the local APIC in the
773 * APIC_BASE MSR. This can only be done in
774 * software for Intel P6 or later and AMD K7
775 * (Model > 1) or later.
777 rdmsr(MSR_IA32_APICBASE, l, h);
778 if (!(l & MSR_IA32_APICBASE_ENABLE)) {
779 printk("Local APIC disabled by BIOS -- reenabling.\n");
780 l &= ~MSR_IA32_APICBASE_BASE;
781 l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
782 wrmsr(MSR_IA32_APICBASE, l, h);
783 enabled_via_apicbase = 1;
787 * The APIC feature bit should now be enabled
790 features = cpuid_edx(1);
791 if (!(features & (1 << X86_FEATURE_APIC))) {
792 printk("Could not enable APIC!\n");
795 set_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
796 mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
798 /* The BIOS may have set up the APIC at some other address */
799 rdmsr(MSR_IA32_APICBASE, l, h);
800 if (l & MSR_IA32_APICBASE_ENABLE)
801 mp_lapic_addr = l & MSR_IA32_APICBASE_BASE;
803 if (nmi_watchdog != NMI_NONE)
804 nmi_watchdog = NMI_LOCAL_APIC;
806 printk("Found and enabled local APIC!\n");
813 printk("No local APIC present or hardware disabled\n");
817 void __init init_apic_mappings(void)
819 unsigned long apic_phys;
822 * If no local APIC can be found then set up a fake all
823 * zeroes page to simulate the local APIC and another
824 * one for the IO-APIC.
826 if (!smp_found_config && detect_init_APIC()) {
827 apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
828 apic_phys = __pa(apic_phys);
830 apic_phys = mp_lapic_addr;
832 set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
833 printk(KERN_DEBUG "mapped APIC to %08lx (%08lx)\n", APIC_BASE,
837 * Fetch the APIC ID of the BSP in case we have a
838 * default configuration (or the MP table is broken).
840 if (boot_cpu_physical_apicid == -1U)
841 boot_cpu_physical_apicid = GET_APIC_ID(apic_read(APIC_ID));
843 #ifdef CONFIG_X86_IO_APIC
845 unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
848 for (i = 0; i < nr_ioapics; i++) {
849 if (smp_found_config) {
850 ioapic_phys = mp_ioapics[i].mpc_apicaddr;
853 "WARNING: bogus zero IO-APIC "
854 "address found in MPTABLE, "
855 "disabling IO/APIC support!\n");
856 smp_found_config = 0;
857 skip_ioapic_setup = 1;
858 goto fake_ioapic_page;
862 ioapic_phys = (unsigned long)
863 alloc_bootmem_pages(PAGE_SIZE);
864 ioapic_phys = __pa(ioapic_phys);
866 set_fixmap_nocache(idx, ioapic_phys);
867 printk(KERN_DEBUG "mapped IOAPIC to %08lx (%08lx)\n",
868 __fix_to_virt(idx), ioapic_phys);
876 * This part sets up the APIC 32 bit clock in LVTT1, with HZ interrupts
877 * per second. We assume that the caller has already set up the local
880 * The APIC timer is not exactly sync with the external timer chip, it
881 * closely follows bus clocks.
885 * The timer chip is already set up at HZ interrupts per second here,
886 * but we do not accept timer interrupts yet. We only allow the BP
889 static unsigned int __init get_8254_timer_count(void)
891 extern spinlock_t i8253_lock;
896 spin_lock_irqsave(&i8253_lock, flags);
898 outb_p(0x00, PIT_MODE);
899 count = inb_p(PIT_CH0);
900 count |= inb_p(PIT_CH0) << 8;
902 spin_unlock_irqrestore(&i8253_lock, flags);
907 /* next tick in 8254 can be caught by catching timer wraparound */
908 static void __init wait_8254_wraparound(void)
910 unsigned int curr_count, prev_count=~0;
913 curr_count = get_8254_timer_count();
916 prev_count = curr_count;
917 curr_count = get_8254_timer_count();
918 delta = curr_count-prev_count;
921 * This limit for delta seems arbitrary, but it isn't, it's
922 * slightly above the level of error a buggy Mercury/Neptune
923 * chipset timer can cause.
926 } while (delta < 300);
930 * Default initialization for 8254 timers. If we use other timers like HPET,
931 * we override this later
933 void (*wait_timer_tick)(void) = wait_8254_wraparound;
936 * This function sets up the local APIC timer, with a timeout of
937 * 'clocks' APIC bus clock. During calibration we actually call
938 * this function twice on the boot CPU, once with a bogus timeout
939 * value, second time for real. The other (noncalibrating) CPUs
940 * call this function only once, with the real, calibrated value.
942 * We do reads before writes even if unnecessary, to get around the
943 * P5 APIC double write bug.
946 #define APIC_DIVISOR 16
948 void __setup_APIC_LVTT(unsigned int clocks)
950 unsigned int lvtt_value, tmp_value, ver;
952 ver = GET_APIC_VERSION(apic_read(APIC_LVR));
953 lvtt_value = APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR;
954 if (!APIC_INTEGRATED(ver))
955 lvtt_value |= SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV);
956 apic_write_around(APIC_LVTT, lvtt_value);
961 tmp_value = apic_read(APIC_TDCR);
962 apic_write_around(APIC_TDCR, (tmp_value
963 & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE))
966 apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR);
969 static void setup_APIC_timer(unsigned int clocks)
973 local_irq_save(flags);
976 * Wait for IRQ0's slice:
980 __setup_APIC_LVTT(clocks);
982 local_irq_restore(flags);
986 * In this function we calibrate APIC bus clocks to the external
987 * timer. Unfortunately we cannot use jiffies and the timer irq
988 * to calibrate, since some later bootup code depends on getting
989 * the first irq? Ugh.
991 * We want to do the calibration only once since we
992 * want to have local timer irqs syncron. CPUs connected
993 * by the same APIC bus have the very same bus frequency.
994 * And we want to have irqs off anyways, no accidental
998 int __init calibrate_APIC_clock(void)
1000 unsigned long long t1 = 0, t2 = 0;
1004 const int LOOPS = HZ/10;
1006 apic_printk(APIC_VERBOSE, "calibrating APIC timer ...\n");
1009 * Put whatever arbitrary (but long enough) timeout
1010 * value into the APIC clock, we just want to get the
1011 * counter running for calibration.
1013 __setup_APIC_LVTT(1000000000);
1016 * The timer chip counts down to zero. Let's wait
1017 * for a wraparound to start exact measurement:
1018 * (the current tick might have been already half done)
1024 * We wrapped around just now. Let's start:
1028 tt1 = apic_read(APIC_TMCCT);
1031 * Let's wait LOOPS wraprounds:
1033 for (i = 0; i < LOOPS; i++)
1036 tt2 = apic_read(APIC_TMCCT);
1041 * The APIC bus clock counter is 32 bits only, it
1042 * might have overflown, but note that we use signed
1043 * longs, thus no extra care needed.
1045 * underflown to be exact, as the timer counts down ;)
1048 result = (tt1-tt2)*APIC_DIVISOR/LOOPS;
1051 apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
1053 ((long)(t2-t1)/LOOPS)/(1000000/HZ),
1054 ((long)(t2-t1)/LOOPS)%(1000000/HZ));
1056 apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
1058 result/(1000000/HZ),
1059 result%(1000000/HZ));
1064 static unsigned int calibration_result;
1066 void __init setup_boot_APIC_clock(void)
1068 apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n");
1069 using_apic_timer = 1;
1071 local_irq_disable();
1073 calibration_result = calibrate_APIC_clock();
1075 * Now set up the timer for real.
1077 setup_APIC_timer(calibration_result);
1082 void __init setup_secondary_APIC_clock(void)
1084 local_irq_disable(); /* FIXME: Do we need this? --RR */
1085 setup_APIC_timer(calibration_result);
1089 void __init disable_APIC_timer(void)
1091 if (using_apic_timer) {
1094 v = apic_read(APIC_LVTT);
1095 apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
1099 void enable_APIC_timer(void)
1101 if (using_apic_timer) {
1104 v = apic_read(APIC_LVTT);
1105 apic_write_around(APIC_LVTT, v & ~APIC_LVT_MASKED);
1110 * the frequency of the profiling timer can be changed
1111 * by writing a multiplier value into /proc/profile.
1113 int setup_profiling_timer(unsigned int multiplier)
1118 * Sanity check. [at least 500 APIC cycles should be
1119 * between APIC interrupts as a rule of thumb, to avoid
1122 if ( (!multiplier) || (calibration_result/multiplier < 500))
1126 * Set the new multiplier for each CPU. CPUs don't start using the
1127 * new values until the next timer interrupt in which they do process
1128 * accounting. At that time they also adjust their APIC timers
1131 for (i = 0; i < NR_CPUS; ++i)
1132 per_cpu(prof_multiplier, i) = multiplier;
1140 * Local timer interrupt handler. It does both profiling and
1141 * process statistics/rescheduling.
1143 * We do profiling in every local tick, statistics/rescheduling
1144 * happen only every 'profiling multiplier' ticks. The default
1145 * multiplier is 1 and it can be changed by writing the new multiplier
1146 * value into /proc/profile.
1149 inline void smp_local_timer_interrupt(struct pt_regs * regs)
1151 int cpu = smp_processor_id();
1153 profile_tick(CPU_PROFILING, regs);
1154 if (--per_cpu(prof_counter, cpu) <= 0) {
1156 * The multiplier may have changed since the last time we got
1157 * to this point as a result of the user writing to
1158 * /proc/profile. In this case we need to adjust the APIC
1159 * timer accordingly.
1161 * Interrupts are already masked off at this point.
1163 per_cpu(prof_counter, cpu) = per_cpu(prof_multiplier, cpu);
1164 if (per_cpu(prof_counter, cpu) !=
1165 per_cpu(prof_old_multiplier, cpu)) {
1168 per_cpu(prof_counter, cpu));
1169 per_cpu(prof_old_multiplier, cpu) =
1170 per_cpu(prof_counter, cpu);
1174 update_process_times(user_mode(regs));
1179 * We take the 'long' return path, and there every subsystem
1180 * grabs the apropriate locks (kernel lock/ irq lock).
1182 * we might want to decouple profiling from the 'long path',
1183 * and do the profiling totally in assembly.
1185 * Currently this isn't too much of an issue (performance wise),
1186 * we can take more than 100K local irqs per second on a 100 MHz P5.
1191 * Local APIC timer interrupt. This is the most natural way for doing
1192 * local interrupts, but local timer interrupts can be emulated by
1193 * broadcast interrupts too. [in case the hw doesn't support APIC timers]
1195 * [ if a single-CPU system runs an SMP kernel then we call the local
1196 * interrupt as well. Thus we cannot inline the local irq ... ]
1199 fastcall void smp_apic_timer_interrupt(struct pt_regs *regs)
1201 int cpu = smp_processor_id();
1204 * the NMI deadlock-detector uses this.
1206 irq_stat[cpu].apic_timer_irqs++;
1209 * NOTE! We'd better ACK the irq immediately,
1210 * because timer handling can be slow.
1214 * update_process_times() expects us to have done irq_enter().
1215 * Besides, if we don't timer interrupts ignore the global
1216 * interrupt lock, which is the WrongThing (tm) to do.
1219 smp_local_timer_interrupt(regs);
1224 * This interrupt should _never_ happen with our APIC/SMP architecture
1226 fastcall void smp_spurious_interrupt(struct pt_regs *regs)
1232 * Check if this really is a spurious interrupt and ACK it
1233 * if it is a vectored one. Just in case...
1234 * Spurious interrupts should not be ACKed.
1236 v = apic_read(APIC_ISR + ((SPURIOUS_APIC_VECTOR & ~0x1f) >> 1));
1237 if (v & (1 << (SPURIOUS_APIC_VECTOR & 0x1f)))
1240 /* see sw-dev-man vol 3, chapter 7.4.13.5 */
1241 printk(KERN_INFO "spurious APIC interrupt on CPU#%d, should never happen.\n",
1242 smp_processor_id());
1247 * This interrupt should never happen with our APIC/SMP architecture
1250 fastcall void smp_error_interrupt(struct pt_regs *regs)
1252 unsigned long v, v1;
1255 /* First tickle the hardware, only then report what went on. -- REW */
1256 v = apic_read(APIC_ESR);
1257 apic_write(APIC_ESR, 0);
1258 v1 = apic_read(APIC_ESR);
1260 atomic_inc(&irq_err_count);
1262 /* Here is what the APIC error bits mean:
1265 2: Send accept error
1266 3: Receive accept error
1268 5: Send illegal vector
1269 6: Received illegal vector
1270 7: Illegal register address
1272 printk (KERN_DEBUG "APIC error on CPU%d: %02lx(%02lx)\n",
1273 smp_processor_id(), v , v1);
1278 * This initializes the IO-APIC and APIC hardware if this is
1281 int __init APIC_init_uniprocessor (void)
1283 if (enable_local_apic < 0)
1284 clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
1286 if (!smp_found_config && !cpu_has_apic)
1290 * Complain if the BIOS pretends there is one.
1292 if (!cpu_has_apic && APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
1293 printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
1294 boot_cpu_physical_apicid);
1298 verify_local_APIC();
1302 phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid);
1306 if (nmi_watchdog == NMI_LOCAL_APIC)
1307 check_nmi_watchdog();
1308 #ifdef CONFIG_X86_IO_APIC
1309 if (smp_found_config)
1310 if (!skip_ioapic_setup && nr_ioapics)
1313 setup_boot_APIC_clock();