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");
224 void disable_local_APIC(void)
231 * Disable APIC (implies clearing of registers
234 value = apic_read(APIC_SPIV);
235 value &= ~APIC_SPIV_APIC_ENABLED;
236 apic_write_around(APIC_SPIV, value);
238 if (enabled_via_apicbase) {
240 rdmsr(MSR_IA32_APICBASE, l, h);
241 l &= ~MSR_IA32_APICBASE_ENABLE;
242 wrmsr(MSR_IA32_APICBASE, l, h);
247 * This is to verify that we're looking at a real local APIC.
248 * Check these against your board if the CPUs aren't getting
249 * started for no apparent reason.
251 int __init verify_local_APIC(void)
253 unsigned int reg0, reg1;
256 * The version register is read-only in a real APIC.
258 reg0 = apic_read(APIC_LVR);
259 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg0);
260 apic_write(APIC_LVR, reg0 ^ APIC_LVR_MASK);
261 reg1 = apic_read(APIC_LVR);
262 apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg1);
265 * The two version reads above should print the same
266 * numbers. If the second one is different, then we
267 * poke at a non-APIC.
273 * Check if the version looks reasonably.
275 reg1 = GET_APIC_VERSION(reg0);
276 if (reg1 == 0x00 || reg1 == 0xff)
279 if (reg1 < 0x02 || reg1 == 0xff)
283 * The ID register is read/write in a real APIC.
285 reg0 = apic_read(APIC_ID);
286 apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg0);
289 * The next two are just to see if we have sane values.
290 * They're only really relevant if we're in Virtual Wire
291 * compatibility mode, but most boxes are anymore.
293 reg0 = apic_read(APIC_LVT0);
294 apic_printk(APIC_DEBUG, "Getting LVT0: %x\n", reg0);
295 reg1 = apic_read(APIC_LVT1);
296 apic_printk(APIC_DEBUG, "Getting LVT1: %x\n", reg1);
301 void __init sync_Arb_IDs(void)
303 /* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 */
304 unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
305 if (ver >= 0x14) /* P4 or higher */
310 apic_wait_icr_idle();
312 apic_printk(APIC_DEBUG, "Synchronizing Arb IDs.\n");
313 apic_write_around(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG
317 extern void __error_in_apic_c (void);
320 * An initial setup of the virtual wire mode.
322 void __init init_bsp_APIC(void)
324 unsigned long value, ver;
327 * Don't do the setup now if we have a SMP BIOS as the
328 * through-I/O-APIC virtual wire mode might be active.
330 if (smp_found_config || !cpu_has_apic)
333 value = apic_read(APIC_LVR);
334 ver = GET_APIC_VERSION(value);
337 * Do not trust the local APIC being empty at bootup.
344 value = apic_read(APIC_SPIV);
345 value &= ~APIC_VECTOR_MASK;
346 value |= APIC_SPIV_APIC_ENABLED;
348 /* This bit is reserved on P4/Xeon and should be cleared */
349 if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 15))
350 value &= ~APIC_SPIV_FOCUS_DISABLED;
352 value |= APIC_SPIV_FOCUS_DISABLED;
353 value |= SPURIOUS_APIC_VECTOR;
354 apic_write_around(APIC_SPIV, value);
357 * Set up the virtual wire mode.
359 apic_write_around(APIC_LVT0, APIC_DM_EXTINT);
361 if (!APIC_INTEGRATED(ver)) /* 82489DX */
362 value |= APIC_LVT_LEVEL_TRIGGER;
363 apic_write_around(APIC_LVT1, value);
366 void __init setup_local_APIC (void)
368 unsigned long oldvalue, value, ver, maxlvt;
370 /* Pound the ESR really hard over the head with a big hammer - mbligh */
372 apic_write(APIC_ESR, 0);
373 apic_write(APIC_ESR, 0);
374 apic_write(APIC_ESR, 0);
375 apic_write(APIC_ESR, 0);
378 value = apic_read(APIC_LVR);
379 ver = GET_APIC_VERSION(value);
381 if ((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f)
385 * Double-check whether this APIC is really registered.
387 if (!apic_id_registered())
391 * Intel recommends to set DFR, LDR and TPR before enabling
392 * an APIC. See e.g. "AP-388 82489DX User's Manual" (Intel
393 * document number 292116). So here it goes...
398 * Set Task Priority to 'accept all'. We never change this
401 value = apic_read(APIC_TASKPRI);
402 value &= ~APIC_TPRI_MASK;
403 apic_write_around(APIC_TASKPRI, value);
406 * Now that we are all set up, enable the APIC
408 value = apic_read(APIC_SPIV);
409 value &= ~APIC_VECTOR_MASK;
413 value |= APIC_SPIV_APIC_ENABLED;
416 * Some unknown Intel IO/APIC (or APIC) errata is biting us with
417 * certain networking cards. If high frequency interrupts are
418 * happening on a particular IOAPIC pin, plus the IOAPIC routing
419 * entry is masked/unmasked at a high rate as well then sooner or
420 * later IOAPIC line gets 'stuck', no more interrupts are received
421 * from the device. If focus CPU is disabled then the hang goes
424 * [ This bug can be reproduced easily with a level-triggered
425 * PCI Ne2000 networking cards and PII/PIII processors, dual
429 * Actually disabling the focus CPU check just makes the hang less
430 * frequent as it makes the interrupt distributon model be more
431 * like LRU than MRU (the short-term load is more even across CPUs).
432 * See also the comment in end_level_ioapic_irq(). --macro
435 /* Enable focus processor (bit==0) */
436 value &= ~APIC_SPIV_FOCUS_DISABLED;
438 /* Disable focus processor (bit==1) */
439 value |= APIC_SPIV_FOCUS_DISABLED;
442 * Set spurious IRQ vector
444 value |= SPURIOUS_APIC_VECTOR;
445 apic_write_around(APIC_SPIV, value);
450 * set up through-local-APIC on the BP's LINT0. This is not
451 * strictly necessery in pure symmetric-IO mode, but sometimes
452 * we delegate interrupts to the 8259A.
455 * TODO: set up through-local-APIC from through-I/O-APIC? --macro
457 value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
458 if (!smp_processor_id() && (pic_mode || !value)) {
459 value = APIC_DM_EXTINT;
460 apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n",
463 value = APIC_DM_EXTINT | APIC_LVT_MASKED;
464 apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n",
467 apic_write_around(APIC_LVT0, value);
470 * only the BP should see the LINT1 NMI signal, obviously.
472 if (!smp_processor_id())
475 value = APIC_DM_NMI | APIC_LVT_MASKED;
476 if (!APIC_INTEGRATED(ver)) /* 82489DX */
477 value |= APIC_LVT_LEVEL_TRIGGER;
478 apic_write_around(APIC_LVT1, value);
480 if (APIC_INTEGRATED(ver) && !esr_disable) { /* !82489DX */
481 maxlvt = get_maxlvt();
482 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
483 apic_write(APIC_ESR, 0);
484 oldvalue = apic_read(APIC_ESR);
486 value = ERROR_APIC_VECTOR; // enables sending errors
487 apic_write_around(APIC_LVTERR, value);
489 * spec says clear errors after enabling vector.
492 apic_write(APIC_ESR, 0);
493 value = apic_read(APIC_ESR);
494 if (value != oldvalue)
495 apic_printk(APIC_VERBOSE, "ESR value before enabling "
496 "vector: 0x%08lx after: 0x%08lx\n",
501 * Something untraceble is creating bad interrupts on
502 * secondary quads ... for the moment, just leave the
503 * ESR disabled - we can't do anything useful with the
504 * errors anyway - mbligh
506 printk("Leaving ESR disabled.\n");
508 printk("No ESR for 82489DX.\n");
511 if (nmi_watchdog == NMI_LOCAL_APIC)
512 setup_apic_nmi_watchdog();
517 * If Linux enabled the LAPIC against the BIOS default
518 * disable it down before re-entering the BIOS on shutdown.
519 * Otherwise the BIOS may get confused and not power-off.
524 if (!cpu_has_apic || !enabled_via_apicbase)
528 disable_local_APIC();
536 /* r/w apic fields */
537 unsigned int apic_id;
538 unsigned int apic_taskpri;
539 unsigned int apic_ldr;
540 unsigned int apic_dfr;
541 unsigned int apic_spiv;
542 unsigned int apic_lvtt;
543 unsigned int apic_lvtpc;
544 unsigned int apic_lvt0;
545 unsigned int apic_lvt1;
546 unsigned int apic_lvterr;
547 unsigned int apic_tmict;
548 unsigned int apic_tdcr;
549 unsigned int apic_thmr;
552 static int lapic_suspend(struct sys_device *dev, u32 state)
556 if (!apic_pm_state.active)
559 apic_pm_state.apic_id = apic_read(APIC_ID);
560 apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
561 apic_pm_state.apic_ldr = apic_read(APIC_LDR);
562 apic_pm_state.apic_dfr = apic_read(APIC_DFR);
563 apic_pm_state.apic_spiv = apic_read(APIC_SPIV);
564 apic_pm_state.apic_lvtt = apic_read(APIC_LVTT);
565 apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC);
566 apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0);
567 apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1);
568 apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
569 apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
570 apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
571 apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
573 local_irq_save(flags);
574 disable_local_APIC();
575 local_irq_restore(flags);
579 static int lapic_resume(struct sys_device *dev)
584 if (!apic_pm_state.active)
587 local_irq_save(flags);
590 * Make sure the APICBASE points to the right address
592 * FIXME! This will be wrong if we ever support suspend on
593 * SMP! We'll need to do this as part of the CPU restore!
595 rdmsr(MSR_IA32_APICBASE, l, h);
596 l &= ~MSR_IA32_APICBASE_BASE;
597 l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr;
598 wrmsr(MSR_IA32_APICBASE, l, h);
600 apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
601 apic_write(APIC_ID, apic_pm_state.apic_id);
602 apic_write(APIC_DFR, apic_pm_state.apic_dfr);
603 apic_write(APIC_LDR, apic_pm_state.apic_ldr);
604 apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri);
605 apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
606 apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
607 apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
608 apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr);
609 apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
610 apic_write(APIC_LVTT, apic_pm_state.apic_lvtt);
611 apic_write(APIC_TDCR, apic_pm_state.apic_tdcr);
612 apic_write(APIC_TMICT, apic_pm_state.apic_tmict);
613 apic_write(APIC_ESR, 0);
615 apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr);
616 apic_write(APIC_ESR, 0);
618 local_irq_restore(flags);
623 * This device has no shutdown method - fully functioning local APICs
624 * are needed on every CPU up until machine_halt/restart/poweroff.
627 static struct sysdev_class lapic_sysclass = {
628 set_kset_name("lapic"),
629 .resume = lapic_resume,
630 .suspend = lapic_suspend,
633 static struct sys_device device_lapic = {
635 .cls = &lapic_sysclass,
638 static void __init apic_pm_activate(void)
640 apic_pm_state.active = 1;
643 static int __init init_lapic_sysfs(void)
649 /* XXX: remove suspend/resume procs if !apic_pm_state.active? */
651 error = sysdev_class_register(&lapic_sysclass);
653 error = sysdev_register(&device_lapic);
656 device_initcall(init_lapic_sysfs);
658 #else /* CONFIG_PM */
660 static void apic_pm_activate(void) { }
662 #endif /* CONFIG_PM */
665 * Detect and enable local APICs on non-SMP boards.
666 * Original code written by Keir Fraser.
670 * Knob to control our willingness to enable the local APIC.
672 int enable_local_apic __initdata = 0; /* -1=force-disable, +1=force-enable */
674 static int __init lapic_disable(char *str)
676 enable_local_apic = -1;
677 clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
680 __setup("nolapic", lapic_disable);
682 static int __init lapic_enable(char *str)
684 enable_local_apic = 1;
687 __setup("lapic", lapic_enable);
689 static int __init apic_set_verbosity(char *str)
691 if (strcmp("debug", str) == 0)
692 apic_verbosity = APIC_DEBUG;
693 else if (strcmp("verbose", str) == 0)
694 apic_verbosity = APIC_VERBOSE;
696 printk(KERN_WARNING "APIC Verbosity level %s not recognised"
697 " use apic=verbose or apic=debug", str);
702 __setup("apic=", apic_set_verbosity);
704 static int __init detect_init_APIC (void)
707 extern void get_cpu_vendor(struct cpuinfo_x86*);
709 /* Disabled by kernel option? */
710 if (enable_local_apic < 0)
713 /* Workaround for us being called before identify_cpu(). */
714 get_cpu_vendor(&boot_cpu_data);
716 switch (boot_cpu_data.x86_vendor) {
718 if ((boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model > 1) ||
719 (boot_cpu_data.x86 == 15))
722 case X86_VENDOR_INTEL:
723 if (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15 ||
724 (boot_cpu_data.x86 == 5 && cpu_has_apic))
733 * Over-ride BIOS and try to enable the local
734 * APIC only if "lapic" specified.
736 if (enable_local_apic <= 0) {
737 printk("Local APIC disabled by BIOS -- "
738 "you can enable it with \"lapic\"\n");
742 * Some BIOSes disable the local APIC in the
743 * APIC_BASE MSR. This can only be done in
744 * software for Intel P6 or later and AMD K7
745 * (Model > 1) or later.
747 rdmsr(MSR_IA32_APICBASE, l, h);
748 if (!(l & MSR_IA32_APICBASE_ENABLE)) {
749 printk("Local APIC disabled by BIOS -- reenabling.\n");
750 l &= ~MSR_IA32_APICBASE_BASE;
751 l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
752 wrmsr(MSR_IA32_APICBASE, l, h);
753 enabled_via_apicbase = 1;
757 * The APIC feature bit should now be enabled
760 features = cpuid_edx(1);
761 if (!(features & (1 << X86_FEATURE_APIC))) {
762 printk("Could not enable APIC!\n");
765 set_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
766 mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
768 /* The BIOS may have set up the APIC at some other address */
769 rdmsr(MSR_IA32_APICBASE, l, h);
770 if (l & MSR_IA32_APICBASE_ENABLE)
771 mp_lapic_addr = l & MSR_IA32_APICBASE_BASE;
773 if (nmi_watchdog != NMI_NONE)
774 nmi_watchdog = NMI_LOCAL_APIC;
776 printk("Found and enabled local APIC!\n");
783 printk("No local APIC present or hardware disabled\n");
787 void __init init_apic_mappings(void)
789 unsigned long apic_phys;
792 * If no local APIC can be found then set up a fake all
793 * zeroes page to simulate the local APIC and another
794 * one for the IO-APIC.
796 if (!smp_found_config && detect_init_APIC()) {
797 apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
798 apic_phys = __pa(apic_phys);
800 apic_phys = mp_lapic_addr;
802 set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
803 printk(KERN_DEBUG "mapped APIC to %08lx (%08lx)\n", APIC_BASE,
807 * Fetch the APIC ID of the BSP in case we have a
808 * default configuration (or the MP table is broken).
810 if (boot_cpu_physical_apicid == -1U)
811 boot_cpu_physical_apicid = GET_APIC_ID(apic_read(APIC_ID));
813 #ifdef CONFIG_X86_IO_APIC
815 unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
818 for (i = 0; i < nr_ioapics; i++) {
819 if (smp_found_config) {
820 ioapic_phys = mp_ioapics[i].mpc_apicaddr;
823 "WARNING: bogus zero IO-APIC "
824 "address found in MPTABLE, "
825 "disabling IO/APIC support!\n");
826 smp_found_config = 0;
827 skip_ioapic_setup = 1;
828 goto fake_ioapic_page;
832 ioapic_phys = (unsigned long)
833 alloc_bootmem_pages(PAGE_SIZE);
834 ioapic_phys = __pa(ioapic_phys);
836 set_fixmap_nocache(idx, ioapic_phys);
837 printk(KERN_DEBUG "mapped IOAPIC to %08lx (%08lx)\n",
838 __fix_to_virt(idx), ioapic_phys);
846 * This part sets up the APIC 32 bit clock in LVTT1, with HZ interrupts
847 * per second. We assume that the caller has already set up the local
850 * The APIC timer is not exactly sync with the external timer chip, it
851 * closely follows bus clocks.
855 * The timer chip is already set up at HZ interrupts per second here,
856 * but we do not accept timer interrupts yet. We only allow the BP
859 static unsigned int __init get_8254_timer_count(void)
861 extern spinlock_t i8253_lock;
866 spin_lock_irqsave(&i8253_lock, flags);
868 outb_p(0x00, PIT_MODE);
869 count = inb_p(PIT_CH0);
870 count |= inb_p(PIT_CH0) << 8;
872 spin_unlock_irqrestore(&i8253_lock, flags);
877 /* next tick in 8254 can be caught by catching timer wraparound */
878 static void __init wait_8254_wraparound(void)
880 unsigned int curr_count, prev_count=~0;
883 curr_count = get_8254_timer_count();
886 prev_count = curr_count;
887 curr_count = get_8254_timer_count();
888 delta = curr_count-prev_count;
891 * This limit for delta seems arbitrary, but it isn't, it's
892 * slightly above the level of error a buggy Mercury/Neptune
893 * chipset timer can cause.
896 } while (delta < 300);
900 * Default initialization for 8254 timers. If we use other timers like HPET,
901 * we override this later
903 void (*wait_timer_tick)(void) = wait_8254_wraparound;
906 * This function sets up the local APIC timer, with a timeout of
907 * 'clocks' APIC bus clock. During calibration we actually call
908 * this function twice on the boot CPU, once with a bogus timeout
909 * value, second time for real. The other (noncalibrating) CPUs
910 * call this function only once, with the real, calibrated value.
912 * We do reads before writes even if unnecessary, to get around the
913 * P5 APIC double write bug.
916 #define APIC_DIVISOR 16
918 void __setup_APIC_LVTT(unsigned int clocks)
920 unsigned int lvtt_value, tmp_value, ver;
922 ver = GET_APIC_VERSION(apic_read(APIC_LVR));
923 lvtt_value = APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR;
924 if (!APIC_INTEGRATED(ver))
925 lvtt_value |= SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV);
926 apic_write_around(APIC_LVTT, lvtt_value);
931 tmp_value = apic_read(APIC_TDCR);
932 apic_write_around(APIC_TDCR, (tmp_value
933 & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE))
936 apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR);
939 static void setup_APIC_timer(unsigned int clocks)
943 local_irq_save(flags);
946 * Wait for IRQ0's slice:
950 __setup_APIC_LVTT(clocks);
952 local_irq_restore(flags);
956 * In this function we calibrate APIC bus clocks to the external
957 * timer. Unfortunately we cannot use jiffies and the timer irq
958 * to calibrate, since some later bootup code depends on getting
959 * the first irq? Ugh.
961 * We want to do the calibration only once since we
962 * want to have local timer irqs syncron. CPUs connected
963 * by the same APIC bus have the very same bus frequency.
964 * And we want to have irqs off anyways, no accidental
968 int __init calibrate_APIC_clock(void)
970 unsigned long long t1 = 0, t2 = 0;
974 const int LOOPS = HZ/10;
976 apic_printk(APIC_VERBOSE, "calibrating APIC timer ...\n");
979 * Put whatever arbitrary (but long enough) timeout
980 * value into the APIC clock, we just want to get the
981 * counter running for calibration.
983 __setup_APIC_LVTT(1000000000);
986 * The timer chip counts down to zero. Let's wait
987 * for a wraparound to start exact measurement:
988 * (the current tick might have been already half done)
994 * We wrapped around just now. Let's start:
998 tt1 = apic_read(APIC_TMCCT);
1001 * Let's wait LOOPS wraprounds:
1003 for (i = 0; i < LOOPS; i++)
1006 tt2 = apic_read(APIC_TMCCT);
1011 * The APIC bus clock counter is 32 bits only, it
1012 * might have overflown, but note that we use signed
1013 * longs, thus no extra care needed.
1015 * underflown to be exact, as the timer counts down ;)
1018 result = (tt1-tt2)*APIC_DIVISOR/LOOPS;
1021 apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
1023 ((long)(t2-t1)/LOOPS)/(1000000/HZ),
1024 ((long)(t2-t1)/LOOPS)%(1000000/HZ));
1026 apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
1028 result/(1000000/HZ),
1029 result%(1000000/HZ));
1034 static unsigned int calibration_result;
1036 void __init setup_boot_APIC_clock(void)
1038 apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n");
1039 using_apic_timer = 1;
1041 local_irq_disable();
1043 calibration_result = calibrate_APIC_clock();
1045 * Now set up the timer for real.
1047 setup_APIC_timer(calibration_result);
1052 void __init setup_secondary_APIC_clock(void)
1054 local_irq_disable(); /* FIXME: Do we need this? --RR */
1055 setup_APIC_timer(calibration_result);
1059 void __init disable_APIC_timer(void)
1061 if (using_apic_timer) {
1064 v = apic_read(APIC_LVTT);
1065 apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
1069 void enable_APIC_timer(void)
1071 if (using_apic_timer) {
1074 v = apic_read(APIC_LVTT);
1075 apic_write_around(APIC_LVTT, v & ~APIC_LVT_MASKED);
1080 * the frequency of the profiling timer can be changed
1081 * by writing a multiplier value into /proc/profile.
1083 int setup_profiling_timer(unsigned int multiplier)
1088 * Sanity check. [at least 500 APIC cycles should be
1089 * between APIC interrupts as a rule of thumb, to avoid
1092 if ( (!multiplier) || (calibration_result/multiplier < 500))
1096 * Set the new multiplier for each CPU. CPUs don't start using the
1097 * new values until the next timer interrupt in which they do process
1098 * accounting. At that time they also adjust their APIC timers
1101 for (i = 0; i < NR_CPUS; ++i)
1102 per_cpu(prof_multiplier, i) = multiplier;
1110 * Local timer interrupt handler. It does both profiling and
1111 * process statistics/rescheduling.
1113 * We do profiling in every local tick, statistics/rescheduling
1114 * happen only every 'profiling multiplier' ticks. The default
1115 * multiplier is 1 and it can be changed by writing the new multiplier
1116 * value into /proc/profile.
1119 inline void smp_local_timer_interrupt(struct pt_regs * regs)
1121 int cpu = smp_processor_id();
1123 profile_tick(CPU_PROFILING, regs);
1124 if (--per_cpu(prof_counter, cpu) <= 0) {
1126 * The multiplier may have changed since the last time we got
1127 * to this point as a result of the user writing to
1128 * /proc/profile. In this case we need to adjust the APIC
1129 * timer accordingly.
1131 * Interrupts are already masked off at this point.
1133 per_cpu(prof_counter, cpu) = per_cpu(prof_multiplier, cpu);
1134 if (per_cpu(prof_counter, cpu) !=
1135 per_cpu(prof_old_multiplier, cpu)) {
1138 per_cpu(prof_counter, cpu));
1139 per_cpu(prof_old_multiplier, cpu) =
1140 per_cpu(prof_counter, cpu);
1144 update_process_times(user_mode(regs));
1149 * We take the 'long' return path, and there every subsystem
1150 * grabs the apropriate locks (kernel lock/ irq lock).
1152 * we might want to decouple profiling from the 'long path',
1153 * and do the profiling totally in assembly.
1155 * Currently this isn't too much of an issue (performance wise),
1156 * we can take more than 100K local irqs per second on a 100 MHz P5.
1161 * Local APIC timer interrupt. This is the most natural way for doing
1162 * local interrupts, but local timer interrupts can be emulated by
1163 * broadcast interrupts too. [in case the hw doesn't support APIC timers]
1165 * [ if a single-CPU system runs an SMP kernel then we call the local
1166 * interrupt as well. Thus we cannot inline the local irq ... ]
1169 fastcall void smp_apic_timer_interrupt(struct pt_regs *regs)
1171 int cpu = smp_processor_id();
1174 * the NMI deadlock-detector uses this.
1176 irq_stat[cpu].apic_timer_irqs++;
1179 * NOTE! We'd better ACK the irq immediately,
1180 * because timer handling can be slow.
1184 * update_process_times() expects us to have done irq_enter().
1185 * Besides, if we don't timer interrupts ignore the global
1186 * interrupt lock, which is the WrongThing (tm) to do.
1189 smp_local_timer_interrupt(regs);
1194 * This interrupt should _never_ happen with our APIC/SMP architecture
1196 fastcall void smp_spurious_interrupt(struct pt_regs *regs)
1202 * Check if this really is a spurious interrupt and ACK it
1203 * if it is a vectored one. Just in case...
1204 * Spurious interrupts should not be ACKed.
1206 v = apic_read(APIC_ISR + ((SPURIOUS_APIC_VECTOR & ~0x1f) >> 1));
1207 if (v & (1 << (SPURIOUS_APIC_VECTOR & 0x1f)))
1210 /* see sw-dev-man vol 3, chapter 7.4.13.5 */
1211 printk(KERN_INFO "spurious APIC interrupt on CPU#%d, should never happen.\n",
1212 smp_processor_id());
1217 * This interrupt should never happen with our APIC/SMP architecture
1220 fastcall void smp_error_interrupt(struct pt_regs *regs)
1222 unsigned long v, v1;
1225 /* First tickle the hardware, only then report what went on. -- REW */
1226 v = apic_read(APIC_ESR);
1227 apic_write(APIC_ESR, 0);
1228 v1 = apic_read(APIC_ESR);
1230 atomic_inc(&irq_err_count);
1232 /* Here is what the APIC error bits mean:
1235 2: Send accept error
1236 3: Receive accept error
1238 5: Send illegal vector
1239 6: Received illegal vector
1240 7: Illegal register address
1242 printk (KERN_DEBUG "APIC error on CPU%d: %02lx(%02lx)\n",
1243 smp_processor_id(), v , v1);
1248 * This initializes the IO-APIC and APIC hardware if this is
1251 int __init APIC_init_uniprocessor (void)
1253 if (enable_local_apic < 0)
1254 clear_bit(X86_FEATURE_APIC, boot_cpu_data.x86_capability);
1256 if (!smp_found_config && !cpu_has_apic)
1260 * Complain if the BIOS pretends there is one.
1262 if (!cpu_has_apic && APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
1263 printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
1264 boot_cpu_physical_apicid);
1268 verify_local_APIC();
1272 phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid);
1276 if (nmi_watchdog == NMI_LOCAL_APIC)
1277 check_nmi_watchdog();
1278 #ifdef CONFIG_X86_IO_APIC
1279 if (smp_found_config)
1280 if (!skip_ioapic_setup && nr_ioapics)
1283 setup_boot_APIC_clock();