xref: /openbmc/linux/arch/x86/kernel/apic/apic.c (revision e3b9f1e8)
1 /*
2  *	Local APIC handling, local APIC timers
3  *
4  *	(c) 1999, 2000, 2009 Ingo Molnar <mingo@redhat.com>
5  *
6  *	Fixes
7  *	Maciej W. Rozycki	:	Bits for genuine 82489DX APICs;
8  *					thanks to Eric Gilmore
9  *					and Rolf G. Tews
10  *					for testing these extensively.
11  *	Maciej W. Rozycki	:	Various updates and fixes.
12  *	Mikael Pettersson	:	Power Management for UP-APIC.
13  *	Pavel Machek and
14  *	Mikael Pettersson	:	PM converted to driver model.
15  */
16 
17 #include <linux/perf_event.h>
18 #include <linux/kernel_stat.h>
19 #include <linux/mc146818rtc.h>
20 #include <linux/acpi_pmtmr.h>
21 #include <linux/clockchips.h>
22 #include <linux/interrupt.h>
23 #include <linux/bootmem.h>
24 #include <linux/ftrace.h>
25 #include <linux/ioport.h>
26 #include <linux/export.h>
27 #include <linux/syscore_ops.h>
28 #include <linux/delay.h>
29 #include <linux/timex.h>
30 #include <linux/i8253.h>
31 #include <linux/dmar.h>
32 #include <linux/init.h>
33 #include <linux/cpu.h>
34 #include <linux/dmi.h>
35 #include <linux/smp.h>
36 #include <linux/mm.h>
37 
38 #include <asm/trace/irq_vectors.h>
39 #include <asm/irq_remapping.h>
40 #include <asm/perf_event.h>
41 #include <asm/x86_init.h>
42 #include <asm/pgalloc.h>
43 #include <linux/atomic.h>
44 #include <asm/mpspec.h>
45 #include <asm/i8259.h>
46 #include <asm/proto.h>
47 #include <asm/apic.h>
48 #include <asm/io_apic.h>
49 #include <asm/desc.h>
50 #include <asm/hpet.h>
51 #include <asm/mtrr.h>
52 #include <asm/time.h>
53 #include <asm/smp.h>
54 #include <asm/mce.h>
55 #include <asm/tsc.h>
56 #include <asm/hypervisor.h>
57 #include <asm/cpu_device_id.h>
58 #include <asm/intel-family.h>
59 
60 unsigned int num_processors;
61 
62 unsigned disabled_cpus;
63 
64 /* Processor that is doing the boot up */
65 unsigned int boot_cpu_physical_apicid = -1U;
66 EXPORT_SYMBOL_GPL(boot_cpu_physical_apicid);
67 
68 u8 boot_cpu_apic_version;
69 
70 /*
71  * The highest APIC ID seen during enumeration.
72  */
73 static unsigned int max_physical_apicid;
74 
75 /*
76  * Bitmask of physically existing CPUs:
77  */
78 physid_mask_t phys_cpu_present_map;
79 
80 /*
81  * Processor to be disabled specified by kernel parameter
82  * disable_cpu_apicid=<int>, mostly used for the kdump 2nd kernel to
83  * avoid undefined behaviour caused by sending INIT from AP to BSP.
84  */
85 static unsigned int disabled_cpu_apicid __read_mostly = BAD_APICID;
86 
87 /*
88  * This variable controls which CPUs receive external NMIs.  By default,
89  * external NMIs are delivered only to the BSP.
90  */
91 static int apic_extnmi = APIC_EXTNMI_BSP;
92 
93 /*
94  * Map cpu index to physical APIC ID
95  */
96 DEFINE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_cpu_to_apicid, BAD_APICID);
97 DEFINE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_bios_cpu_apicid, BAD_APICID);
98 DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid, U32_MAX);
99 EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_apicid);
100 EXPORT_EARLY_PER_CPU_SYMBOL(x86_bios_cpu_apicid);
101 EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_acpiid);
102 
103 #ifdef CONFIG_X86_32
104 
105 /*
106  * On x86_32, the mapping between cpu and logical apicid may vary
107  * depending on apic in use.  The following early percpu variable is
108  * used for the mapping.  This is where the behaviors of x86_64 and 32
109  * actually diverge.  Let's keep it ugly for now.
110  */
111 DEFINE_EARLY_PER_CPU_READ_MOSTLY(int, x86_cpu_to_logical_apicid, BAD_APICID);
112 
113 /* Local APIC was disabled by the BIOS and enabled by the kernel */
114 static int enabled_via_apicbase;
115 
116 /*
117  * Handle interrupt mode configuration register (IMCR).
118  * This register controls whether the interrupt signals
119  * that reach the BSP come from the master PIC or from the
120  * local APIC. Before entering Symmetric I/O Mode, either
121  * the BIOS or the operating system must switch out of
122  * PIC Mode by changing the IMCR.
123  */
124 static inline void imcr_pic_to_apic(void)
125 {
126 	/* select IMCR register */
127 	outb(0x70, 0x22);
128 	/* NMI and 8259 INTR go through APIC */
129 	outb(0x01, 0x23);
130 }
131 
132 static inline void imcr_apic_to_pic(void)
133 {
134 	/* select IMCR register */
135 	outb(0x70, 0x22);
136 	/* NMI and 8259 INTR go directly to BSP */
137 	outb(0x00, 0x23);
138 }
139 #endif
140 
141 /*
142  * Knob to control our willingness to enable the local APIC.
143  *
144  * +1=force-enable
145  */
146 static int force_enable_local_apic __initdata;
147 
148 /*
149  * APIC command line parameters
150  */
151 static int __init parse_lapic(char *arg)
152 {
153 	if (IS_ENABLED(CONFIG_X86_32) && !arg)
154 		force_enable_local_apic = 1;
155 	else if (arg && !strncmp(arg, "notscdeadline", 13))
156 		setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER);
157 	return 0;
158 }
159 early_param("lapic", parse_lapic);
160 
161 #ifdef CONFIG_X86_64
162 static int apic_calibrate_pmtmr __initdata;
163 static __init int setup_apicpmtimer(char *s)
164 {
165 	apic_calibrate_pmtmr = 1;
166 	notsc_setup(NULL);
167 	return 0;
168 }
169 __setup("apicpmtimer", setup_apicpmtimer);
170 #endif
171 
172 unsigned long mp_lapic_addr;
173 int disable_apic;
174 /* Disable local APIC timer from the kernel commandline or via dmi quirk */
175 static int disable_apic_timer __initdata;
176 /* Local APIC timer works in C2 */
177 int local_apic_timer_c2_ok;
178 EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
179 
180 /*
181  * Debug level, exported for io_apic.c
182  */
183 unsigned int apic_verbosity;
184 
185 int pic_mode;
186 
187 /* Have we found an MP table */
188 int smp_found_config;
189 
190 static struct resource lapic_resource = {
191 	.name = "Local APIC",
192 	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
193 };
194 
195 unsigned int lapic_timer_frequency = 0;
196 
197 static void apic_pm_activate(void);
198 
199 static unsigned long apic_phys;
200 
201 /*
202  * Get the LAPIC version
203  */
204 static inline int lapic_get_version(void)
205 {
206 	return GET_APIC_VERSION(apic_read(APIC_LVR));
207 }
208 
209 /*
210  * Check, if the APIC is integrated or a separate chip
211  */
212 static inline int lapic_is_integrated(void)
213 {
214 	return APIC_INTEGRATED(lapic_get_version());
215 }
216 
217 /*
218  * Check, whether this is a modern or a first generation APIC
219  */
220 static int modern_apic(void)
221 {
222 	/* AMD systems use old APIC versions, so check the CPU */
223 	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
224 	    boot_cpu_data.x86 >= 0xf)
225 		return 1;
226 	return lapic_get_version() >= 0x14;
227 }
228 
229 /*
230  * right after this call apic become NOOP driven
231  * so apic->write/read doesn't do anything
232  */
233 static void __init apic_disable(void)
234 {
235 	pr_info("APIC: switched to apic NOOP\n");
236 	apic = &apic_noop;
237 }
238 
239 void native_apic_wait_icr_idle(void)
240 {
241 	while (apic_read(APIC_ICR) & APIC_ICR_BUSY)
242 		cpu_relax();
243 }
244 
245 u32 native_safe_apic_wait_icr_idle(void)
246 {
247 	u32 send_status;
248 	int timeout;
249 
250 	timeout = 0;
251 	do {
252 		send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
253 		if (!send_status)
254 			break;
255 		inc_irq_stat(icr_read_retry_count);
256 		udelay(100);
257 	} while (timeout++ < 1000);
258 
259 	return send_status;
260 }
261 
262 void native_apic_icr_write(u32 low, u32 id)
263 {
264 	unsigned long flags;
265 
266 	local_irq_save(flags);
267 	apic_write(APIC_ICR2, SET_APIC_DEST_FIELD(id));
268 	apic_write(APIC_ICR, low);
269 	local_irq_restore(flags);
270 }
271 
272 u64 native_apic_icr_read(void)
273 {
274 	u32 icr1, icr2;
275 
276 	icr2 = apic_read(APIC_ICR2);
277 	icr1 = apic_read(APIC_ICR);
278 
279 	return icr1 | ((u64)icr2 << 32);
280 }
281 
282 #ifdef CONFIG_X86_32
283 /**
284  * get_physical_broadcast - Get number of physical broadcast IDs
285  */
286 int get_physical_broadcast(void)
287 {
288 	return modern_apic() ? 0xff : 0xf;
289 }
290 #endif
291 
292 /**
293  * lapic_get_maxlvt - get the maximum number of local vector table entries
294  */
295 int lapic_get_maxlvt(void)
296 {
297 	/*
298 	 * - we always have APIC integrated on 64bit mode
299 	 * - 82489DXs do not report # of LVT entries
300 	 */
301 	return lapic_is_integrated() ? GET_APIC_MAXLVT(apic_read(APIC_LVR)) : 2;
302 }
303 
304 /*
305  * Local APIC timer
306  */
307 
308 /* Clock divisor */
309 #define APIC_DIVISOR 16
310 #define TSC_DIVISOR  8
311 
312 /*
313  * This function sets up the local APIC timer, with a timeout of
314  * 'clocks' APIC bus clock. During calibration we actually call
315  * this function twice on the boot CPU, once with a bogus timeout
316  * value, second time for real. The other (noncalibrating) CPUs
317  * call this function only once, with the real, calibrated value.
318  *
319  * We do reads before writes even if unnecessary, to get around the
320  * P5 APIC double write bug.
321  */
322 static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen)
323 {
324 	unsigned int lvtt_value, tmp_value;
325 
326 	lvtt_value = LOCAL_TIMER_VECTOR;
327 	if (!oneshot)
328 		lvtt_value |= APIC_LVT_TIMER_PERIODIC;
329 	else if (boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER))
330 		lvtt_value |= APIC_LVT_TIMER_TSCDEADLINE;
331 
332 	if (!lapic_is_integrated())
333 		lvtt_value |= SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV);
334 
335 	if (!irqen)
336 		lvtt_value |= APIC_LVT_MASKED;
337 
338 	apic_write(APIC_LVTT, lvtt_value);
339 
340 	if (lvtt_value & APIC_LVT_TIMER_TSCDEADLINE) {
341 		/*
342 		 * See Intel SDM: TSC-Deadline Mode chapter. In xAPIC mode,
343 		 * writing to the APIC LVTT and TSC_DEADLINE MSR isn't serialized.
344 		 * According to Intel, MFENCE can do the serialization here.
345 		 */
346 		asm volatile("mfence" : : : "memory");
347 
348 		printk_once(KERN_DEBUG "TSC deadline timer enabled\n");
349 		return;
350 	}
351 
352 	/*
353 	 * Divide PICLK by 16
354 	 */
355 	tmp_value = apic_read(APIC_TDCR);
356 	apic_write(APIC_TDCR,
357 		(tmp_value & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE)) |
358 		APIC_TDR_DIV_16);
359 
360 	if (!oneshot)
361 		apic_write(APIC_TMICT, clocks / APIC_DIVISOR);
362 }
363 
364 /*
365  * Setup extended LVT, AMD specific
366  *
367  * Software should use the LVT offsets the BIOS provides.  The offsets
368  * are determined by the subsystems using it like those for MCE
369  * threshold or IBS.  On K8 only offset 0 (APIC500) and MCE interrupts
370  * are supported. Beginning with family 10h at least 4 offsets are
371  * available.
372  *
373  * Since the offsets must be consistent for all cores, we keep track
374  * of the LVT offsets in software and reserve the offset for the same
375  * vector also to be used on other cores. An offset is freed by
376  * setting the entry to APIC_EILVT_MASKED.
377  *
378  * If the BIOS is right, there should be no conflicts. Otherwise a
379  * "[Firmware Bug]: ..." error message is generated. However, if
380  * software does not properly determines the offsets, it is not
381  * necessarily a BIOS bug.
382  */
383 
384 static atomic_t eilvt_offsets[APIC_EILVT_NR_MAX];
385 
386 static inline int eilvt_entry_is_changeable(unsigned int old, unsigned int new)
387 {
388 	return (old & APIC_EILVT_MASKED)
389 		|| (new == APIC_EILVT_MASKED)
390 		|| ((new & ~APIC_EILVT_MASKED) == old);
391 }
392 
393 static unsigned int reserve_eilvt_offset(int offset, unsigned int new)
394 {
395 	unsigned int rsvd, vector;
396 
397 	if (offset >= APIC_EILVT_NR_MAX)
398 		return ~0;
399 
400 	rsvd = atomic_read(&eilvt_offsets[offset]);
401 	do {
402 		vector = rsvd & ~APIC_EILVT_MASKED;	/* 0: unassigned */
403 		if (vector && !eilvt_entry_is_changeable(vector, new))
404 			/* may not change if vectors are different */
405 			return rsvd;
406 		rsvd = atomic_cmpxchg(&eilvt_offsets[offset], rsvd, new);
407 	} while (rsvd != new);
408 
409 	rsvd &= ~APIC_EILVT_MASKED;
410 	if (rsvd && rsvd != vector)
411 		pr_info("LVT offset %d assigned for vector 0x%02x\n",
412 			offset, rsvd);
413 
414 	return new;
415 }
416 
417 /*
418  * If mask=1, the LVT entry does not generate interrupts while mask=0
419  * enables the vector. See also the BKDGs. Must be called with
420  * preemption disabled.
421  */
422 
423 int setup_APIC_eilvt(u8 offset, u8 vector, u8 msg_type, u8 mask)
424 {
425 	unsigned long reg = APIC_EILVTn(offset);
426 	unsigned int new, old, reserved;
427 
428 	new = (mask << 16) | (msg_type << 8) | vector;
429 	old = apic_read(reg);
430 	reserved = reserve_eilvt_offset(offset, new);
431 
432 	if (reserved != new) {
433 		pr_err(FW_BUG "cpu %d, try to use APIC%lX (LVT offset %d) for "
434 		       "vector 0x%x, but the register is already in use for "
435 		       "vector 0x%x on another cpu\n",
436 		       smp_processor_id(), reg, offset, new, reserved);
437 		return -EINVAL;
438 	}
439 
440 	if (!eilvt_entry_is_changeable(old, new)) {
441 		pr_err(FW_BUG "cpu %d, try to use APIC%lX (LVT offset %d) for "
442 		       "vector 0x%x, but the register is already in use for "
443 		       "vector 0x%x on this cpu\n",
444 		       smp_processor_id(), reg, offset, new, old);
445 		return -EBUSY;
446 	}
447 
448 	apic_write(reg, new);
449 
450 	return 0;
451 }
452 EXPORT_SYMBOL_GPL(setup_APIC_eilvt);
453 
454 /*
455  * Program the next event, relative to now
456  */
457 static int lapic_next_event(unsigned long delta,
458 			    struct clock_event_device *evt)
459 {
460 	apic_write(APIC_TMICT, delta);
461 	return 0;
462 }
463 
464 static int lapic_next_deadline(unsigned long delta,
465 			       struct clock_event_device *evt)
466 {
467 	u64 tsc;
468 
469 	tsc = rdtsc();
470 	wrmsrl(MSR_IA32_TSC_DEADLINE, tsc + (((u64) delta) * TSC_DIVISOR));
471 	return 0;
472 }
473 
474 static int lapic_timer_shutdown(struct clock_event_device *evt)
475 {
476 	unsigned int v;
477 
478 	/* Lapic used as dummy for broadcast ? */
479 	if (evt->features & CLOCK_EVT_FEAT_DUMMY)
480 		return 0;
481 
482 	v = apic_read(APIC_LVTT);
483 	v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
484 	apic_write(APIC_LVTT, v);
485 	apic_write(APIC_TMICT, 0);
486 	return 0;
487 }
488 
489 static inline int
490 lapic_timer_set_periodic_oneshot(struct clock_event_device *evt, bool oneshot)
491 {
492 	/* Lapic used as dummy for broadcast ? */
493 	if (evt->features & CLOCK_EVT_FEAT_DUMMY)
494 		return 0;
495 
496 	__setup_APIC_LVTT(lapic_timer_frequency, oneshot, 1);
497 	return 0;
498 }
499 
500 static int lapic_timer_set_periodic(struct clock_event_device *evt)
501 {
502 	return lapic_timer_set_periodic_oneshot(evt, false);
503 }
504 
505 static int lapic_timer_set_oneshot(struct clock_event_device *evt)
506 {
507 	return lapic_timer_set_periodic_oneshot(evt, true);
508 }
509 
510 /*
511  * Local APIC timer broadcast function
512  */
513 static void lapic_timer_broadcast(const struct cpumask *mask)
514 {
515 #ifdef CONFIG_SMP
516 	apic->send_IPI_mask(mask, LOCAL_TIMER_VECTOR);
517 #endif
518 }
519 
520 
521 /*
522  * The local apic timer can be used for any function which is CPU local.
523  */
524 static struct clock_event_device lapic_clockevent = {
525 	.name				= "lapic",
526 	.features			= CLOCK_EVT_FEAT_PERIODIC |
527 					  CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP
528 					  | CLOCK_EVT_FEAT_DUMMY,
529 	.shift				= 32,
530 	.set_state_shutdown		= lapic_timer_shutdown,
531 	.set_state_periodic		= lapic_timer_set_periodic,
532 	.set_state_oneshot		= lapic_timer_set_oneshot,
533 	.set_state_oneshot_stopped	= lapic_timer_shutdown,
534 	.set_next_event			= lapic_next_event,
535 	.broadcast			= lapic_timer_broadcast,
536 	.rating				= 100,
537 	.irq				= -1,
538 };
539 static DEFINE_PER_CPU(struct clock_event_device, lapic_events);
540 
541 #define DEADLINE_MODEL_MATCH_FUNC(model, func)	\
542 	{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long)&func }
543 
544 #define DEADLINE_MODEL_MATCH_REV(model, rev)	\
545 	{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, (unsigned long)rev }
546 
547 static u32 hsx_deadline_rev(void)
548 {
549 	switch (boot_cpu_data.x86_stepping) {
550 	case 0x02: return 0x3a; /* EP */
551 	case 0x04: return 0x0f; /* EX */
552 	}
553 
554 	return ~0U;
555 }
556 
557 static u32 bdx_deadline_rev(void)
558 {
559 	switch (boot_cpu_data.x86_stepping) {
560 	case 0x02: return 0x00000011;
561 	case 0x03: return 0x0700000e;
562 	case 0x04: return 0x0f00000c;
563 	case 0x05: return 0x0e000003;
564 	}
565 
566 	return ~0U;
567 }
568 
569 static u32 skx_deadline_rev(void)
570 {
571 	switch (boot_cpu_data.x86_stepping) {
572 	case 0x03: return 0x01000136;
573 	case 0x04: return 0x02000014;
574 	}
575 
576 	return ~0U;
577 }
578 
579 static const struct x86_cpu_id deadline_match[] = {
580 	DEADLINE_MODEL_MATCH_FUNC( INTEL_FAM6_HASWELL_X,	hsx_deadline_rev),
581 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_BROADWELL_X,	0x0b000020),
582 	DEADLINE_MODEL_MATCH_FUNC( INTEL_FAM6_BROADWELL_XEON_D,	bdx_deadline_rev),
583 	DEADLINE_MODEL_MATCH_FUNC( INTEL_FAM6_SKYLAKE_X,	skx_deadline_rev),
584 
585 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_HASWELL_CORE,	0x22),
586 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_HASWELL_ULT,	0x20),
587 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_HASWELL_GT3E,	0x17),
588 
589 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_BROADWELL_CORE,	0x25),
590 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_BROADWELL_GT3E,	0x17),
591 
592 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_SKYLAKE_MOBILE,	0xb2),
593 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_SKYLAKE_DESKTOP,	0xb2),
594 
595 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_KABYLAKE_MOBILE,	0x52),
596 	DEADLINE_MODEL_MATCH_REV ( INTEL_FAM6_KABYLAKE_DESKTOP,	0x52),
597 
598 	{},
599 };
600 
601 static void apic_check_deadline_errata(void)
602 {
603 	const struct x86_cpu_id *m;
604 	u32 rev;
605 
606 	if (!boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER) ||
607 	    boot_cpu_has(X86_FEATURE_HYPERVISOR))
608 		return;
609 
610 	m = x86_match_cpu(deadline_match);
611 	if (!m)
612 		return;
613 
614 	/*
615 	 * Function pointers will have the MSB set due to address layout,
616 	 * immediate revisions will not.
617 	 */
618 	if ((long)m->driver_data < 0)
619 		rev = ((u32 (*)(void))(m->driver_data))();
620 	else
621 		rev = (u32)m->driver_data;
622 
623 	if (boot_cpu_data.microcode >= rev)
624 		return;
625 
626 	setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER);
627 	pr_err(FW_BUG "TSC_DEADLINE disabled due to Errata; "
628 	       "please update microcode to version: 0x%x (or later)\n", rev);
629 }
630 
631 /*
632  * Setup the local APIC timer for this CPU. Copy the initialized values
633  * of the boot CPU and register the clock event in the framework.
634  */
635 static void setup_APIC_timer(void)
636 {
637 	struct clock_event_device *levt = this_cpu_ptr(&lapic_events);
638 
639 	if (this_cpu_has(X86_FEATURE_ARAT)) {
640 		lapic_clockevent.features &= ~CLOCK_EVT_FEAT_C3STOP;
641 		/* Make LAPIC timer preferrable over percpu HPET */
642 		lapic_clockevent.rating = 150;
643 	}
644 
645 	memcpy(levt, &lapic_clockevent, sizeof(*levt));
646 	levt->cpumask = cpumask_of(smp_processor_id());
647 
648 	if (this_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) {
649 		levt->name = "lapic-deadline";
650 		levt->features &= ~(CLOCK_EVT_FEAT_PERIODIC |
651 				    CLOCK_EVT_FEAT_DUMMY);
652 		levt->set_next_event = lapic_next_deadline;
653 		clockevents_config_and_register(levt,
654 						tsc_khz * (1000 / TSC_DIVISOR),
655 						0xF, ~0UL);
656 	} else
657 		clockevents_register_device(levt);
658 }
659 
660 /*
661  * Install the updated TSC frequency from recalibration at the TSC
662  * deadline clockevent devices.
663  */
664 static void __lapic_update_tsc_freq(void *info)
665 {
666 	struct clock_event_device *levt = this_cpu_ptr(&lapic_events);
667 
668 	if (!this_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER))
669 		return;
670 
671 	clockevents_update_freq(levt, tsc_khz * (1000 / TSC_DIVISOR));
672 }
673 
674 void lapic_update_tsc_freq(void)
675 {
676 	/*
677 	 * The clockevent device's ->mult and ->shift can both be
678 	 * changed. In order to avoid races, schedule the frequency
679 	 * update code on each CPU.
680 	 */
681 	on_each_cpu(__lapic_update_tsc_freq, NULL, 0);
682 }
683 
684 /*
685  * In this functions we calibrate APIC bus clocks to the external timer.
686  *
687  * We want to do the calibration only once since we want to have local timer
688  * irqs syncron. CPUs connected by the same APIC bus have the very same bus
689  * frequency.
690  *
691  * This was previously done by reading the PIT/HPET and waiting for a wrap
692  * around to find out, that a tick has elapsed. I have a box, where the PIT
693  * readout is broken, so it never gets out of the wait loop again. This was
694  * also reported by others.
695  *
696  * Monitoring the jiffies value is inaccurate and the clockevents
697  * infrastructure allows us to do a simple substitution of the interrupt
698  * handler.
699  *
700  * The calibration routine also uses the pm_timer when possible, as the PIT
701  * happens to run way too slow (factor 2.3 on my VAIO CoreDuo, which goes
702  * back to normal later in the boot process).
703  */
704 
705 #define LAPIC_CAL_LOOPS		(HZ/10)
706 
707 static __initdata int lapic_cal_loops = -1;
708 static __initdata long lapic_cal_t1, lapic_cal_t2;
709 static __initdata unsigned long long lapic_cal_tsc1, lapic_cal_tsc2;
710 static __initdata unsigned long lapic_cal_pm1, lapic_cal_pm2;
711 static __initdata unsigned long lapic_cal_j1, lapic_cal_j2;
712 
713 /*
714  * Temporary interrupt handler.
715  */
716 static void __init lapic_cal_handler(struct clock_event_device *dev)
717 {
718 	unsigned long long tsc = 0;
719 	long tapic = apic_read(APIC_TMCCT);
720 	unsigned long pm = acpi_pm_read_early();
721 
722 	if (boot_cpu_has(X86_FEATURE_TSC))
723 		tsc = rdtsc();
724 
725 	switch (lapic_cal_loops++) {
726 	case 0:
727 		lapic_cal_t1 = tapic;
728 		lapic_cal_tsc1 = tsc;
729 		lapic_cal_pm1 = pm;
730 		lapic_cal_j1 = jiffies;
731 		break;
732 
733 	case LAPIC_CAL_LOOPS:
734 		lapic_cal_t2 = tapic;
735 		lapic_cal_tsc2 = tsc;
736 		if (pm < lapic_cal_pm1)
737 			pm += ACPI_PM_OVRRUN;
738 		lapic_cal_pm2 = pm;
739 		lapic_cal_j2 = jiffies;
740 		break;
741 	}
742 }
743 
744 static int __init
745 calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc)
746 {
747 	const long pm_100ms = PMTMR_TICKS_PER_SEC / 10;
748 	const long pm_thresh = pm_100ms / 100;
749 	unsigned long mult;
750 	u64 res;
751 
752 #ifndef CONFIG_X86_PM_TIMER
753 	return -1;
754 #endif
755 
756 	apic_printk(APIC_VERBOSE, "... PM-Timer delta = %ld\n", deltapm);
757 
758 	/* Check, if the PM timer is available */
759 	if (!deltapm)
760 		return -1;
761 
762 	mult = clocksource_hz2mult(PMTMR_TICKS_PER_SEC, 22);
763 
764 	if (deltapm > (pm_100ms - pm_thresh) &&
765 	    deltapm < (pm_100ms + pm_thresh)) {
766 		apic_printk(APIC_VERBOSE, "... PM-Timer result ok\n");
767 		return 0;
768 	}
769 
770 	res = (((u64)deltapm) *  mult) >> 22;
771 	do_div(res, 1000000);
772 	pr_warning("APIC calibration not consistent "
773 		   "with PM-Timer: %ldms instead of 100ms\n",(long)res);
774 
775 	/* Correct the lapic counter value */
776 	res = (((u64)(*delta)) * pm_100ms);
777 	do_div(res, deltapm);
778 	pr_info("APIC delta adjusted to PM-Timer: "
779 		"%lu (%ld)\n", (unsigned long)res, *delta);
780 	*delta = (long)res;
781 
782 	/* Correct the tsc counter value */
783 	if (boot_cpu_has(X86_FEATURE_TSC)) {
784 		res = (((u64)(*deltatsc)) * pm_100ms);
785 		do_div(res, deltapm);
786 		apic_printk(APIC_VERBOSE, "TSC delta adjusted to "
787 					  "PM-Timer: %lu (%ld)\n",
788 					(unsigned long)res, *deltatsc);
789 		*deltatsc = (long)res;
790 	}
791 
792 	return 0;
793 }
794 
795 static int __init calibrate_APIC_clock(void)
796 {
797 	struct clock_event_device *levt = this_cpu_ptr(&lapic_events);
798 	void (*real_handler)(struct clock_event_device *dev);
799 	unsigned long deltaj;
800 	long delta, deltatsc;
801 	int pm_referenced = 0;
802 
803 	/**
804 	 * check if lapic timer has already been calibrated by platform
805 	 * specific routine, such as tsc calibration code. if so, we just fill
806 	 * in the clockevent structure and return.
807 	 */
808 
809 	if (boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) {
810 		return 0;
811 	} else if (lapic_timer_frequency) {
812 		apic_printk(APIC_VERBOSE, "lapic timer already calibrated %d\n",
813 				lapic_timer_frequency);
814 		lapic_clockevent.mult = div_sc(lapic_timer_frequency/APIC_DIVISOR,
815 					TICK_NSEC, lapic_clockevent.shift);
816 		lapic_clockevent.max_delta_ns =
817 			clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
818 		lapic_clockevent.max_delta_ticks = 0x7FFFFF;
819 		lapic_clockevent.min_delta_ns =
820 			clockevent_delta2ns(0xF, &lapic_clockevent);
821 		lapic_clockevent.min_delta_ticks = 0xF;
822 		lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
823 		return 0;
824 	}
825 
826 	apic_printk(APIC_VERBOSE, "Using local APIC timer interrupts.\n"
827 		    "calibrating APIC timer ...\n");
828 
829 	local_irq_disable();
830 
831 	/* Replace the global interrupt handler */
832 	real_handler = global_clock_event->event_handler;
833 	global_clock_event->event_handler = lapic_cal_handler;
834 
835 	/*
836 	 * Setup the APIC counter to maximum. There is no way the lapic
837 	 * can underflow in the 100ms detection time frame
838 	 */
839 	__setup_APIC_LVTT(0xffffffff, 0, 0);
840 
841 	/* Let the interrupts run */
842 	local_irq_enable();
843 
844 	while (lapic_cal_loops <= LAPIC_CAL_LOOPS)
845 		cpu_relax();
846 
847 	local_irq_disable();
848 
849 	/* Restore the real event handler */
850 	global_clock_event->event_handler = real_handler;
851 
852 	/* Build delta t1-t2 as apic timer counts down */
853 	delta = lapic_cal_t1 - lapic_cal_t2;
854 	apic_printk(APIC_VERBOSE, "... lapic delta = %ld\n", delta);
855 
856 	deltatsc = (long)(lapic_cal_tsc2 - lapic_cal_tsc1);
857 
858 	/* we trust the PM based calibration if possible */
859 	pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
860 					&delta, &deltatsc);
861 
862 	/* Calculate the scaled math multiplication factor */
863 	lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
864 				       lapic_clockevent.shift);
865 	lapic_clockevent.max_delta_ns =
866 		clockevent_delta2ns(0x7FFFFFFF, &lapic_clockevent);
867 	lapic_clockevent.max_delta_ticks = 0x7FFFFFFF;
868 	lapic_clockevent.min_delta_ns =
869 		clockevent_delta2ns(0xF, &lapic_clockevent);
870 	lapic_clockevent.min_delta_ticks = 0xF;
871 
872 	lapic_timer_frequency = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
873 
874 	apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
875 	apic_printk(APIC_VERBOSE, "..... mult: %u\n", lapic_clockevent.mult);
876 	apic_printk(APIC_VERBOSE, "..... calibration result: %u\n",
877 		    lapic_timer_frequency);
878 
879 	if (boot_cpu_has(X86_FEATURE_TSC)) {
880 		apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
881 			    "%ld.%04ld MHz.\n",
882 			    (deltatsc / LAPIC_CAL_LOOPS) / (1000000 / HZ),
883 			    (deltatsc / LAPIC_CAL_LOOPS) % (1000000 / HZ));
884 	}
885 
886 	apic_printk(APIC_VERBOSE, "..... host bus clock speed is "
887 		    "%u.%04u MHz.\n",
888 		    lapic_timer_frequency / (1000000 / HZ),
889 		    lapic_timer_frequency % (1000000 / HZ));
890 
891 	/*
892 	 * Do a sanity check on the APIC calibration result
893 	 */
894 	if (lapic_timer_frequency < (1000000 / HZ)) {
895 		local_irq_enable();
896 		pr_warning("APIC frequency too slow, disabling apic timer\n");
897 		return -1;
898 	}
899 
900 	levt->features &= ~CLOCK_EVT_FEAT_DUMMY;
901 
902 	/*
903 	 * PM timer calibration failed or not turned on
904 	 * so lets try APIC timer based calibration
905 	 */
906 	if (!pm_referenced) {
907 		apic_printk(APIC_VERBOSE, "... verify APIC timer\n");
908 
909 		/*
910 		 * Setup the apic timer manually
911 		 */
912 		levt->event_handler = lapic_cal_handler;
913 		lapic_timer_set_periodic(levt);
914 		lapic_cal_loops = -1;
915 
916 		/* Let the interrupts run */
917 		local_irq_enable();
918 
919 		while (lapic_cal_loops <= LAPIC_CAL_LOOPS)
920 			cpu_relax();
921 
922 		/* Stop the lapic timer */
923 		local_irq_disable();
924 		lapic_timer_shutdown(levt);
925 
926 		/* Jiffies delta */
927 		deltaj = lapic_cal_j2 - lapic_cal_j1;
928 		apic_printk(APIC_VERBOSE, "... jiffies delta = %lu\n", deltaj);
929 
930 		/* Check, if the jiffies result is consistent */
931 		if (deltaj >= LAPIC_CAL_LOOPS-2 && deltaj <= LAPIC_CAL_LOOPS+2)
932 			apic_printk(APIC_VERBOSE, "... jiffies result ok\n");
933 		else
934 			levt->features |= CLOCK_EVT_FEAT_DUMMY;
935 	}
936 	local_irq_enable();
937 
938 	if (levt->features & CLOCK_EVT_FEAT_DUMMY) {
939 		pr_warning("APIC timer disabled due to verification failure\n");
940 			return -1;
941 	}
942 
943 	return 0;
944 }
945 
946 /*
947  * Setup the boot APIC
948  *
949  * Calibrate and verify the result.
950  */
951 void __init setup_boot_APIC_clock(void)
952 {
953 	/*
954 	 * The local apic timer can be disabled via the kernel
955 	 * commandline or from the CPU detection code. Register the lapic
956 	 * timer as a dummy clock event source on SMP systems, so the
957 	 * broadcast mechanism is used. On UP systems simply ignore it.
958 	 */
959 	if (disable_apic_timer) {
960 		pr_info("Disabling APIC timer\n");
961 		/* No broadcast on UP ! */
962 		if (num_possible_cpus() > 1) {
963 			lapic_clockevent.mult = 1;
964 			setup_APIC_timer();
965 		}
966 		return;
967 	}
968 
969 	if (calibrate_APIC_clock()) {
970 		/* No broadcast on UP ! */
971 		if (num_possible_cpus() > 1)
972 			setup_APIC_timer();
973 		return;
974 	}
975 
976 	/*
977 	 * If nmi_watchdog is set to IO_APIC, we need the
978 	 * PIT/HPET going.  Otherwise register lapic as a dummy
979 	 * device.
980 	 */
981 	lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
982 
983 	/* Setup the lapic or request the broadcast */
984 	setup_APIC_timer();
985 	amd_e400_c1e_apic_setup();
986 }
987 
988 void setup_secondary_APIC_clock(void)
989 {
990 	setup_APIC_timer();
991 	amd_e400_c1e_apic_setup();
992 }
993 
994 /*
995  * The guts of the apic timer interrupt
996  */
997 static void local_apic_timer_interrupt(void)
998 {
999 	struct clock_event_device *evt = this_cpu_ptr(&lapic_events);
1000 
1001 	/*
1002 	 * Normally we should not be here till LAPIC has been initialized but
1003 	 * in some cases like kdump, its possible that there is a pending LAPIC
1004 	 * timer interrupt from previous kernel's context and is delivered in
1005 	 * new kernel the moment interrupts are enabled.
1006 	 *
1007 	 * Interrupts are enabled early and LAPIC is setup much later, hence
1008 	 * its possible that when we get here evt->event_handler is NULL.
1009 	 * Check for event_handler being NULL and discard the interrupt as
1010 	 * spurious.
1011 	 */
1012 	if (!evt->event_handler) {
1013 		pr_warning("Spurious LAPIC timer interrupt on cpu %d\n",
1014 			   smp_processor_id());
1015 		/* Switch it off */
1016 		lapic_timer_shutdown(evt);
1017 		return;
1018 	}
1019 
1020 	/*
1021 	 * the NMI deadlock-detector uses this.
1022 	 */
1023 	inc_irq_stat(apic_timer_irqs);
1024 
1025 	evt->event_handler(evt);
1026 }
1027 
1028 /*
1029  * Local APIC timer interrupt. This is the most natural way for doing
1030  * local interrupts, but local timer interrupts can be emulated by
1031  * broadcast interrupts too. [in case the hw doesn't support APIC timers]
1032  *
1033  * [ if a single-CPU system runs an SMP kernel then we call the local
1034  *   interrupt as well. Thus we cannot inline the local irq ... ]
1035  */
1036 __visible void __irq_entry smp_apic_timer_interrupt(struct pt_regs *regs)
1037 {
1038 	struct pt_regs *old_regs = set_irq_regs(regs);
1039 
1040 	/*
1041 	 * NOTE! We'd better ACK the irq immediately,
1042 	 * because timer handling can be slow.
1043 	 *
1044 	 * update_process_times() expects us to have done irq_enter().
1045 	 * Besides, if we don't timer interrupts ignore the global
1046 	 * interrupt lock, which is the WrongThing (tm) to do.
1047 	 */
1048 	entering_ack_irq();
1049 	trace_local_timer_entry(LOCAL_TIMER_VECTOR);
1050 	local_apic_timer_interrupt();
1051 	trace_local_timer_exit(LOCAL_TIMER_VECTOR);
1052 	exiting_irq();
1053 
1054 	set_irq_regs(old_regs);
1055 }
1056 
1057 int setup_profiling_timer(unsigned int multiplier)
1058 {
1059 	return -EINVAL;
1060 }
1061 
1062 /*
1063  * Local APIC start and shutdown
1064  */
1065 
1066 /**
1067  * clear_local_APIC - shutdown the local APIC
1068  *
1069  * This is called, when a CPU is disabled and before rebooting, so the state of
1070  * the local APIC has no dangling leftovers. Also used to cleanout any BIOS
1071  * leftovers during boot.
1072  */
1073 void clear_local_APIC(void)
1074 {
1075 	int maxlvt;
1076 	u32 v;
1077 
1078 	/* APIC hasn't been mapped yet */
1079 	if (!x2apic_mode && !apic_phys)
1080 		return;
1081 
1082 	maxlvt = lapic_get_maxlvt();
1083 	/*
1084 	 * Masking an LVT entry can trigger a local APIC error
1085 	 * if the vector is zero. Mask LVTERR first to prevent this.
1086 	 */
1087 	if (maxlvt >= 3) {
1088 		v = ERROR_APIC_VECTOR; /* any non-zero vector will do */
1089 		apic_write(APIC_LVTERR, v | APIC_LVT_MASKED);
1090 	}
1091 	/*
1092 	 * Careful: we have to set masks only first to deassert
1093 	 * any level-triggered sources.
1094 	 */
1095 	v = apic_read(APIC_LVTT);
1096 	apic_write(APIC_LVTT, v | APIC_LVT_MASKED);
1097 	v = apic_read(APIC_LVT0);
1098 	apic_write(APIC_LVT0, v | APIC_LVT_MASKED);
1099 	v = apic_read(APIC_LVT1);
1100 	apic_write(APIC_LVT1, v | APIC_LVT_MASKED);
1101 	if (maxlvt >= 4) {
1102 		v = apic_read(APIC_LVTPC);
1103 		apic_write(APIC_LVTPC, v | APIC_LVT_MASKED);
1104 	}
1105 
1106 	/* lets not touch this if we didn't frob it */
1107 #ifdef CONFIG_X86_THERMAL_VECTOR
1108 	if (maxlvt >= 5) {
1109 		v = apic_read(APIC_LVTTHMR);
1110 		apic_write(APIC_LVTTHMR, v | APIC_LVT_MASKED);
1111 	}
1112 #endif
1113 #ifdef CONFIG_X86_MCE_INTEL
1114 	if (maxlvt >= 6) {
1115 		v = apic_read(APIC_LVTCMCI);
1116 		if (!(v & APIC_LVT_MASKED))
1117 			apic_write(APIC_LVTCMCI, v | APIC_LVT_MASKED);
1118 	}
1119 #endif
1120 
1121 	/*
1122 	 * Clean APIC state for other OSs:
1123 	 */
1124 	apic_write(APIC_LVTT, APIC_LVT_MASKED);
1125 	apic_write(APIC_LVT0, APIC_LVT_MASKED);
1126 	apic_write(APIC_LVT1, APIC_LVT_MASKED);
1127 	if (maxlvt >= 3)
1128 		apic_write(APIC_LVTERR, APIC_LVT_MASKED);
1129 	if (maxlvt >= 4)
1130 		apic_write(APIC_LVTPC, APIC_LVT_MASKED);
1131 
1132 	/* Integrated APIC (!82489DX) ? */
1133 	if (lapic_is_integrated()) {
1134 		if (maxlvt > 3)
1135 			/* Clear ESR due to Pentium errata 3AP and 11AP */
1136 			apic_write(APIC_ESR, 0);
1137 		apic_read(APIC_ESR);
1138 	}
1139 }
1140 
1141 /**
1142  * disable_local_APIC - clear and disable the local APIC
1143  */
1144 void disable_local_APIC(void)
1145 {
1146 	unsigned int value;
1147 
1148 	/* APIC hasn't been mapped yet */
1149 	if (!x2apic_mode && !apic_phys)
1150 		return;
1151 
1152 	clear_local_APIC();
1153 
1154 	/*
1155 	 * Disable APIC (implies clearing of registers
1156 	 * for 82489DX!).
1157 	 */
1158 	value = apic_read(APIC_SPIV);
1159 	value &= ~APIC_SPIV_APIC_ENABLED;
1160 	apic_write(APIC_SPIV, value);
1161 
1162 #ifdef CONFIG_X86_32
1163 	/*
1164 	 * When LAPIC was disabled by the BIOS and enabled by the kernel,
1165 	 * restore the disabled state.
1166 	 */
1167 	if (enabled_via_apicbase) {
1168 		unsigned int l, h;
1169 
1170 		rdmsr(MSR_IA32_APICBASE, l, h);
1171 		l &= ~MSR_IA32_APICBASE_ENABLE;
1172 		wrmsr(MSR_IA32_APICBASE, l, h);
1173 	}
1174 #endif
1175 }
1176 
1177 /*
1178  * If Linux enabled the LAPIC against the BIOS default disable it down before
1179  * re-entering the BIOS on shutdown.  Otherwise the BIOS may get confused and
1180  * not power-off.  Additionally clear all LVT entries before disable_local_APIC
1181  * for the case where Linux didn't enable the LAPIC.
1182  */
1183 void lapic_shutdown(void)
1184 {
1185 	unsigned long flags;
1186 
1187 	if (!boot_cpu_has(X86_FEATURE_APIC) && !apic_from_smp_config())
1188 		return;
1189 
1190 	local_irq_save(flags);
1191 
1192 #ifdef CONFIG_X86_32
1193 	if (!enabled_via_apicbase)
1194 		clear_local_APIC();
1195 	else
1196 #endif
1197 		disable_local_APIC();
1198 
1199 
1200 	local_irq_restore(flags);
1201 }
1202 
1203 /**
1204  * sync_Arb_IDs - synchronize APIC bus arbitration IDs
1205  */
1206 void __init sync_Arb_IDs(void)
1207 {
1208 	/*
1209 	 * Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 And not
1210 	 * needed on AMD.
1211 	 */
1212 	if (modern_apic() || boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
1213 		return;
1214 
1215 	/*
1216 	 * Wait for idle.
1217 	 */
1218 	apic_wait_icr_idle();
1219 
1220 	apic_printk(APIC_DEBUG, "Synchronizing Arb IDs.\n");
1221 	apic_write(APIC_ICR, APIC_DEST_ALLINC |
1222 			APIC_INT_LEVELTRIG | APIC_DM_INIT);
1223 }
1224 
1225 enum apic_intr_mode_id apic_intr_mode;
1226 
1227 static int __init apic_intr_mode_select(void)
1228 {
1229 	/* Check kernel option */
1230 	if (disable_apic) {
1231 		pr_info("APIC disabled via kernel command line\n");
1232 		return APIC_PIC;
1233 	}
1234 
1235 	/* Check BIOS */
1236 #ifdef CONFIG_X86_64
1237 	/* On 64-bit, the APIC must be integrated, Check local APIC only */
1238 	if (!boot_cpu_has(X86_FEATURE_APIC)) {
1239 		disable_apic = 1;
1240 		pr_info("APIC disabled by BIOS\n");
1241 		return APIC_PIC;
1242 	}
1243 #else
1244 	/* On 32-bit, the APIC may be integrated APIC or 82489DX */
1245 
1246 	/* Neither 82489DX nor integrated APIC ? */
1247 	if (!boot_cpu_has(X86_FEATURE_APIC) && !smp_found_config) {
1248 		disable_apic = 1;
1249 		return APIC_PIC;
1250 	}
1251 
1252 	/* If the BIOS pretends there is an integrated APIC ? */
1253 	if (!boot_cpu_has(X86_FEATURE_APIC) &&
1254 		APIC_INTEGRATED(boot_cpu_apic_version)) {
1255 		disable_apic = 1;
1256 		pr_err(FW_BUG "Local APIC %d not detected, force emulation\n",
1257 				       boot_cpu_physical_apicid);
1258 		return APIC_PIC;
1259 	}
1260 #endif
1261 
1262 	/* Check MP table or ACPI MADT configuration */
1263 	if (!smp_found_config) {
1264 		disable_ioapic_support();
1265 		if (!acpi_lapic) {
1266 			pr_info("APIC: ACPI MADT or MP tables are not detected\n");
1267 			return APIC_VIRTUAL_WIRE_NO_CONFIG;
1268 		}
1269 		return APIC_VIRTUAL_WIRE;
1270 	}
1271 
1272 #ifdef CONFIG_SMP
1273 	/* If SMP should be disabled, then really disable it! */
1274 	if (!setup_max_cpus) {
1275 		pr_info("APIC: SMP mode deactivated\n");
1276 		return APIC_SYMMETRIC_IO_NO_ROUTING;
1277 	}
1278 
1279 	if (read_apic_id() != boot_cpu_physical_apicid) {
1280 		panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
1281 		     read_apic_id(), boot_cpu_physical_apicid);
1282 		/* Or can we switch back to PIC here? */
1283 	}
1284 #endif
1285 
1286 	return APIC_SYMMETRIC_IO;
1287 }
1288 
1289 /*
1290  * An initial setup of the virtual wire mode.
1291  */
1292 void __init init_bsp_APIC(void)
1293 {
1294 	unsigned int value;
1295 
1296 	/*
1297 	 * Don't do the setup now if we have a SMP BIOS as the
1298 	 * through-I/O-APIC virtual wire mode might be active.
1299 	 */
1300 	if (smp_found_config || !boot_cpu_has(X86_FEATURE_APIC))
1301 		return;
1302 
1303 	/*
1304 	 * Do not trust the local APIC being empty at bootup.
1305 	 */
1306 	clear_local_APIC();
1307 
1308 	/*
1309 	 * Enable APIC.
1310 	 */
1311 	value = apic_read(APIC_SPIV);
1312 	value &= ~APIC_VECTOR_MASK;
1313 	value |= APIC_SPIV_APIC_ENABLED;
1314 
1315 #ifdef CONFIG_X86_32
1316 	/* This bit is reserved on P4/Xeon and should be cleared */
1317 	if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&
1318 	    (boot_cpu_data.x86 == 15))
1319 		value &= ~APIC_SPIV_FOCUS_DISABLED;
1320 	else
1321 #endif
1322 		value |= APIC_SPIV_FOCUS_DISABLED;
1323 	value |= SPURIOUS_APIC_VECTOR;
1324 	apic_write(APIC_SPIV, value);
1325 
1326 	/*
1327 	 * Set up the virtual wire mode.
1328 	 */
1329 	apic_write(APIC_LVT0, APIC_DM_EXTINT);
1330 	value = APIC_DM_NMI;
1331 	if (!lapic_is_integrated())		/* 82489DX */
1332 		value |= APIC_LVT_LEVEL_TRIGGER;
1333 	if (apic_extnmi == APIC_EXTNMI_NONE)
1334 		value |= APIC_LVT_MASKED;
1335 	apic_write(APIC_LVT1, value);
1336 }
1337 
1338 /* Init the interrupt delivery mode for the BSP */
1339 void __init apic_intr_mode_init(void)
1340 {
1341 	bool upmode = IS_ENABLED(CONFIG_UP_LATE_INIT);
1342 
1343 	apic_intr_mode = apic_intr_mode_select();
1344 
1345 	switch (apic_intr_mode) {
1346 	case APIC_PIC:
1347 		pr_info("APIC: Keep in PIC mode(8259)\n");
1348 		return;
1349 	case APIC_VIRTUAL_WIRE:
1350 		pr_info("APIC: Switch to virtual wire mode setup\n");
1351 		default_setup_apic_routing();
1352 		break;
1353 	case APIC_VIRTUAL_WIRE_NO_CONFIG:
1354 		pr_info("APIC: Switch to virtual wire mode setup with no configuration\n");
1355 		upmode = true;
1356 		default_setup_apic_routing();
1357 		break;
1358 	case APIC_SYMMETRIC_IO:
1359 		pr_info("APIC: Switch to symmetric I/O mode setup\n");
1360 		default_setup_apic_routing();
1361 		break;
1362 	case APIC_SYMMETRIC_IO_NO_ROUTING:
1363 		pr_info("APIC: Switch to symmetric I/O mode setup in no SMP routine\n");
1364 		break;
1365 	}
1366 
1367 	apic_bsp_setup(upmode);
1368 }
1369 
1370 static void lapic_setup_esr(void)
1371 {
1372 	unsigned int oldvalue, value, maxlvt;
1373 
1374 	if (!lapic_is_integrated()) {
1375 		pr_info("No ESR for 82489DX.\n");
1376 		return;
1377 	}
1378 
1379 	if (apic->disable_esr) {
1380 		/*
1381 		 * Something untraceable is creating bad interrupts on
1382 		 * secondary quads ... for the moment, just leave the
1383 		 * ESR disabled - we can't do anything useful with the
1384 		 * errors anyway - mbligh
1385 		 */
1386 		pr_info("Leaving ESR disabled.\n");
1387 		return;
1388 	}
1389 
1390 	maxlvt = lapic_get_maxlvt();
1391 	if (maxlvt > 3)		/* Due to the Pentium erratum 3AP. */
1392 		apic_write(APIC_ESR, 0);
1393 	oldvalue = apic_read(APIC_ESR);
1394 
1395 	/* enables sending errors */
1396 	value = ERROR_APIC_VECTOR;
1397 	apic_write(APIC_LVTERR, value);
1398 
1399 	/*
1400 	 * spec says clear errors after enabling vector.
1401 	 */
1402 	if (maxlvt > 3)
1403 		apic_write(APIC_ESR, 0);
1404 	value = apic_read(APIC_ESR);
1405 	if (value != oldvalue)
1406 		apic_printk(APIC_VERBOSE, "ESR value before enabling "
1407 			"vector: 0x%08x  after: 0x%08x\n",
1408 			oldvalue, value);
1409 }
1410 
1411 /**
1412  * setup_local_APIC - setup the local APIC
1413  *
1414  * Used to setup local APIC while initializing BSP or bringing up APs.
1415  * Always called with preemption disabled.
1416  */
1417 void setup_local_APIC(void)
1418 {
1419 	int cpu = smp_processor_id();
1420 	unsigned int value, queued;
1421 	int i, j, acked = 0;
1422 	unsigned long long tsc = 0, ntsc;
1423 	long long max_loops = cpu_khz ? cpu_khz : 1000000;
1424 
1425 	if (boot_cpu_has(X86_FEATURE_TSC))
1426 		tsc = rdtsc();
1427 
1428 	if (disable_apic) {
1429 		disable_ioapic_support();
1430 		return;
1431 	}
1432 
1433 #ifdef CONFIG_X86_32
1434 	/* Pound the ESR really hard over the head with a big hammer - mbligh */
1435 	if (lapic_is_integrated() && apic->disable_esr) {
1436 		apic_write(APIC_ESR, 0);
1437 		apic_write(APIC_ESR, 0);
1438 		apic_write(APIC_ESR, 0);
1439 		apic_write(APIC_ESR, 0);
1440 	}
1441 #endif
1442 	perf_events_lapic_init();
1443 
1444 	/*
1445 	 * Double-check whether this APIC is really registered.
1446 	 * This is meaningless in clustered apic mode, so we skip it.
1447 	 */
1448 	BUG_ON(!apic->apic_id_registered());
1449 
1450 	/*
1451 	 * Intel recommends to set DFR, LDR and TPR before enabling
1452 	 * an APIC.  See e.g. "AP-388 82489DX User's Manual" (Intel
1453 	 * document number 292116).  So here it goes...
1454 	 */
1455 	apic->init_apic_ldr();
1456 
1457 #ifdef CONFIG_X86_32
1458 	/*
1459 	 * APIC LDR is initialized.  If logical_apicid mapping was
1460 	 * initialized during get_smp_config(), make sure it matches the
1461 	 * actual value.
1462 	 */
1463 	i = early_per_cpu(x86_cpu_to_logical_apicid, cpu);
1464 	WARN_ON(i != BAD_APICID && i != logical_smp_processor_id());
1465 	/* always use the value from LDR */
1466 	early_per_cpu(x86_cpu_to_logical_apicid, cpu) =
1467 		logical_smp_processor_id();
1468 #endif
1469 
1470 	/*
1471 	 * Set Task Priority to 'accept all'. We never change this
1472 	 * later on.
1473 	 */
1474 	value = apic_read(APIC_TASKPRI);
1475 	value &= ~APIC_TPRI_MASK;
1476 	apic_write(APIC_TASKPRI, value);
1477 
1478 	/*
1479 	 * After a crash, we no longer service the interrupts and a pending
1480 	 * interrupt from previous kernel might still have ISR bit set.
1481 	 *
1482 	 * Most probably by now CPU has serviced that pending interrupt and
1483 	 * it might not have done the ack_APIC_irq() because it thought,
1484 	 * interrupt came from i8259 as ExtInt. LAPIC did not get EOI so it
1485 	 * does not clear the ISR bit and cpu thinks it has already serivced
1486 	 * the interrupt. Hence a vector might get locked. It was noticed
1487 	 * for timer irq (vector 0x31). Issue an extra EOI to clear ISR.
1488 	 */
1489 	do {
1490 		queued = 0;
1491 		for (i = APIC_ISR_NR - 1; i >= 0; i--)
1492 			queued |= apic_read(APIC_IRR + i*0x10);
1493 
1494 		for (i = APIC_ISR_NR - 1; i >= 0; i--) {
1495 			value = apic_read(APIC_ISR + i*0x10);
1496 			for (j = 31; j >= 0; j--) {
1497 				if (value & (1<<j)) {
1498 					ack_APIC_irq();
1499 					acked++;
1500 				}
1501 			}
1502 		}
1503 		if (acked > 256) {
1504 			printk(KERN_ERR "LAPIC pending interrupts after %d EOI\n",
1505 			       acked);
1506 			break;
1507 		}
1508 		if (queued) {
1509 			if (boot_cpu_has(X86_FEATURE_TSC) && cpu_khz) {
1510 				ntsc = rdtsc();
1511 				max_loops = (cpu_khz << 10) - (ntsc - tsc);
1512 			} else
1513 				max_loops--;
1514 		}
1515 	} while (queued && max_loops > 0);
1516 	WARN_ON(max_loops <= 0);
1517 
1518 	/*
1519 	 * Now that we are all set up, enable the APIC
1520 	 */
1521 	value = apic_read(APIC_SPIV);
1522 	value &= ~APIC_VECTOR_MASK;
1523 	/*
1524 	 * Enable APIC
1525 	 */
1526 	value |= APIC_SPIV_APIC_ENABLED;
1527 
1528 #ifdef CONFIG_X86_32
1529 	/*
1530 	 * Some unknown Intel IO/APIC (or APIC) errata is biting us with
1531 	 * certain networking cards. If high frequency interrupts are
1532 	 * happening on a particular IOAPIC pin, plus the IOAPIC routing
1533 	 * entry is masked/unmasked at a high rate as well then sooner or
1534 	 * later IOAPIC line gets 'stuck', no more interrupts are received
1535 	 * from the device. If focus CPU is disabled then the hang goes
1536 	 * away, oh well :-(
1537 	 *
1538 	 * [ This bug can be reproduced easily with a level-triggered
1539 	 *   PCI Ne2000 networking cards and PII/PIII processors, dual
1540 	 *   BX chipset. ]
1541 	 */
1542 	/*
1543 	 * Actually disabling the focus CPU check just makes the hang less
1544 	 * frequent as it makes the interrupt distributon model be more
1545 	 * like LRU than MRU (the short-term load is more even across CPUs).
1546 	 */
1547 
1548 	/*
1549 	 * - enable focus processor (bit==0)
1550 	 * - 64bit mode always use processor focus
1551 	 *   so no need to set it
1552 	 */
1553 	value &= ~APIC_SPIV_FOCUS_DISABLED;
1554 #endif
1555 
1556 	/*
1557 	 * Set spurious IRQ vector
1558 	 */
1559 	value |= SPURIOUS_APIC_VECTOR;
1560 	apic_write(APIC_SPIV, value);
1561 
1562 	/*
1563 	 * Set up LVT0, LVT1:
1564 	 *
1565 	 * set up through-local-APIC on the boot CPU's LINT0. This is not
1566 	 * strictly necessary in pure symmetric-IO mode, but sometimes
1567 	 * we delegate interrupts to the 8259A.
1568 	 */
1569 	/*
1570 	 * TODO: set up through-local-APIC from through-I/O-APIC? --macro
1571 	 */
1572 	value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
1573 	if (!cpu && (pic_mode || !value)) {
1574 		value = APIC_DM_EXTINT;
1575 		apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n", cpu);
1576 	} else {
1577 		value = APIC_DM_EXTINT | APIC_LVT_MASKED;
1578 		apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n", cpu);
1579 	}
1580 	apic_write(APIC_LVT0, value);
1581 
1582 	/*
1583 	 * Only the BSP sees the LINT1 NMI signal by default. This can be
1584 	 * modified by apic_extnmi= boot option.
1585 	 */
1586 	if ((!cpu && apic_extnmi != APIC_EXTNMI_NONE) ||
1587 	    apic_extnmi == APIC_EXTNMI_ALL)
1588 		value = APIC_DM_NMI;
1589 	else
1590 		value = APIC_DM_NMI | APIC_LVT_MASKED;
1591 
1592 	/* Is 82489DX ? */
1593 	if (!lapic_is_integrated())
1594 		value |= APIC_LVT_LEVEL_TRIGGER;
1595 	apic_write(APIC_LVT1, value);
1596 
1597 #ifdef CONFIG_X86_MCE_INTEL
1598 	/* Recheck CMCI information after local APIC is up on CPU #0 */
1599 	if (!cpu)
1600 		cmci_recheck();
1601 #endif
1602 }
1603 
1604 static void end_local_APIC_setup(void)
1605 {
1606 	lapic_setup_esr();
1607 
1608 #ifdef CONFIG_X86_32
1609 	{
1610 		unsigned int value;
1611 		/* Disable the local apic timer */
1612 		value = apic_read(APIC_LVTT);
1613 		value |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
1614 		apic_write(APIC_LVTT, value);
1615 	}
1616 #endif
1617 
1618 	apic_pm_activate();
1619 }
1620 
1621 /*
1622  * APIC setup function for application processors. Called from smpboot.c
1623  */
1624 void apic_ap_setup(void)
1625 {
1626 	setup_local_APIC();
1627 	end_local_APIC_setup();
1628 }
1629 
1630 #ifdef CONFIG_X86_X2APIC
1631 int x2apic_mode;
1632 
1633 enum {
1634 	X2APIC_OFF,
1635 	X2APIC_ON,
1636 	X2APIC_DISABLED,
1637 };
1638 static int x2apic_state;
1639 
1640 static void __x2apic_disable(void)
1641 {
1642 	u64 msr;
1643 
1644 	if (!boot_cpu_has(X86_FEATURE_APIC))
1645 		return;
1646 
1647 	rdmsrl(MSR_IA32_APICBASE, msr);
1648 	if (!(msr & X2APIC_ENABLE))
1649 		return;
1650 	/* Disable xapic and x2apic first and then reenable xapic mode */
1651 	wrmsrl(MSR_IA32_APICBASE, msr & ~(X2APIC_ENABLE | XAPIC_ENABLE));
1652 	wrmsrl(MSR_IA32_APICBASE, msr & ~X2APIC_ENABLE);
1653 	printk_once(KERN_INFO "x2apic disabled\n");
1654 }
1655 
1656 static void __x2apic_enable(void)
1657 {
1658 	u64 msr;
1659 
1660 	rdmsrl(MSR_IA32_APICBASE, msr);
1661 	if (msr & X2APIC_ENABLE)
1662 		return;
1663 	wrmsrl(MSR_IA32_APICBASE, msr | X2APIC_ENABLE);
1664 	printk_once(KERN_INFO "x2apic enabled\n");
1665 }
1666 
1667 static int __init setup_nox2apic(char *str)
1668 {
1669 	if (x2apic_enabled()) {
1670 		int apicid = native_apic_msr_read(APIC_ID);
1671 
1672 		if (apicid >= 255) {
1673 			pr_warning("Apicid: %08x, cannot enforce nox2apic\n",
1674 				   apicid);
1675 			return 0;
1676 		}
1677 		pr_warning("x2apic already enabled.\n");
1678 		__x2apic_disable();
1679 	}
1680 	setup_clear_cpu_cap(X86_FEATURE_X2APIC);
1681 	x2apic_state = X2APIC_DISABLED;
1682 	x2apic_mode = 0;
1683 	return 0;
1684 }
1685 early_param("nox2apic", setup_nox2apic);
1686 
1687 /* Called from cpu_init() to enable x2apic on (secondary) cpus */
1688 void x2apic_setup(void)
1689 {
1690 	/*
1691 	 * If x2apic is not in ON state, disable it if already enabled
1692 	 * from BIOS.
1693 	 */
1694 	if (x2apic_state != X2APIC_ON) {
1695 		__x2apic_disable();
1696 		return;
1697 	}
1698 	__x2apic_enable();
1699 }
1700 
1701 static __init void x2apic_disable(void)
1702 {
1703 	u32 x2apic_id, state = x2apic_state;
1704 
1705 	x2apic_mode = 0;
1706 	x2apic_state = X2APIC_DISABLED;
1707 
1708 	if (state != X2APIC_ON)
1709 		return;
1710 
1711 	x2apic_id = read_apic_id();
1712 	if (x2apic_id >= 255)
1713 		panic("Cannot disable x2apic, id: %08x\n", x2apic_id);
1714 
1715 	__x2apic_disable();
1716 	register_lapic_address(mp_lapic_addr);
1717 }
1718 
1719 static __init void x2apic_enable(void)
1720 {
1721 	if (x2apic_state != X2APIC_OFF)
1722 		return;
1723 
1724 	x2apic_mode = 1;
1725 	x2apic_state = X2APIC_ON;
1726 	__x2apic_enable();
1727 }
1728 
1729 static __init void try_to_enable_x2apic(int remap_mode)
1730 {
1731 	if (x2apic_state == X2APIC_DISABLED)
1732 		return;
1733 
1734 	if (remap_mode != IRQ_REMAP_X2APIC_MODE) {
1735 		/* IR is required if there is APIC ID > 255 even when running
1736 		 * under KVM
1737 		 */
1738 		if (max_physical_apicid > 255 ||
1739 		    !x86_init.hyper.x2apic_available()) {
1740 			pr_info("x2apic: IRQ remapping doesn't support X2APIC mode\n");
1741 			x2apic_disable();
1742 			return;
1743 		}
1744 
1745 		/*
1746 		 * without IR all CPUs can be addressed by IOAPIC/MSI
1747 		 * only in physical mode
1748 		 */
1749 		x2apic_phys = 1;
1750 	}
1751 	x2apic_enable();
1752 }
1753 
1754 void __init check_x2apic(void)
1755 {
1756 	if (x2apic_enabled()) {
1757 		pr_info("x2apic: enabled by BIOS, switching to x2apic ops\n");
1758 		x2apic_mode = 1;
1759 		x2apic_state = X2APIC_ON;
1760 	} else if (!boot_cpu_has(X86_FEATURE_X2APIC)) {
1761 		x2apic_state = X2APIC_DISABLED;
1762 	}
1763 }
1764 #else /* CONFIG_X86_X2APIC */
1765 static int __init validate_x2apic(void)
1766 {
1767 	if (!apic_is_x2apic_enabled())
1768 		return 0;
1769 	/*
1770 	 * Checkme: Can we simply turn off x2apic here instead of panic?
1771 	 */
1772 	panic("BIOS has enabled x2apic but kernel doesn't support x2apic, please disable x2apic in BIOS.\n");
1773 }
1774 early_initcall(validate_x2apic);
1775 
1776 static inline void try_to_enable_x2apic(int remap_mode) { }
1777 static inline void __x2apic_enable(void) { }
1778 #endif /* !CONFIG_X86_X2APIC */
1779 
1780 void __init enable_IR_x2apic(void)
1781 {
1782 	unsigned long flags;
1783 	int ret, ir_stat;
1784 
1785 	if (skip_ioapic_setup) {
1786 		pr_info("Not enabling interrupt remapping due to skipped IO-APIC setup\n");
1787 		return;
1788 	}
1789 
1790 	ir_stat = irq_remapping_prepare();
1791 	if (ir_stat < 0 && !x2apic_supported())
1792 		return;
1793 
1794 	ret = save_ioapic_entries();
1795 	if (ret) {
1796 		pr_info("Saving IO-APIC state failed: %d\n", ret);
1797 		return;
1798 	}
1799 
1800 	local_irq_save(flags);
1801 	legacy_pic->mask_all();
1802 	mask_ioapic_entries();
1803 
1804 	/* If irq_remapping_prepare() succeeded, try to enable it */
1805 	if (ir_stat >= 0)
1806 		ir_stat = irq_remapping_enable();
1807 	/* ir_stat contains the remap mode or an error code */
1808 	try_to_enable_x2apic(ir_stat);
1809 
1810 	if (ir_stat < 0)
1811 		restore_ioapic_entries();
1812 	legacy_pic->restore_mask();
1813 	local_irq_restore(flags);
1814 }
1815 
1816 #ifdef CONFIG_X86_64
1817 /*
1818  * Detect and enable local APICs on non-SMP boards.
1819  * Original code written by Keir Fraser.
1820  * On AMD64 we trust the BIOS - if it says no APIC it is likely
1821  * not correctly set up (usually the APIC timer won't work etc.)
1822  */
1823 static int __init detect_init_APIC(void)
1824 {
1825 	if (!boot_cpu_has(X86_FEATURE_APIC)) {
1826 		pr_info("No local APIC present\n");
1827 		return -1;
1828 	}
1829 
1830 	mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
1831 	return 0;
1832 }
1833 #else
1834 
1835 static int __init apic_verify(void)
1836 {
1837 	u32 features, h, l;
1838 
1839 	/*
1840 	 * The APIC feature bit should now be enabled
1841 	 * in `cpuid'
1842 	 */
1843 	features = cpuid_edx(1);
1844 	if (!(features & (1 << X86_FEATURE_APIC))) {
1845 		pr_warning("Could not enable APIC!\n");
1846 		return -1;
1847 	}
1848 	set_cpu_cap(&boot_cpu_data, X86_FEATURE_APIC);
1849 	mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
1850 
1851 	/* The BIOS may have set up the APIC at some other address */
1852 	if (boot_cpu_data.x86 >= 6) {
1853 		rdmsr(MSR_IA32_APICBASE, l, h);
1854 		if (l & MSR_IA32_APICBASE_ENABLE)
1855 			mp_lapic_addr = l & MSR_IA32_APICBASE_BASE;
1856 	}
1857 
1858 	pr_info("Found and enabled local APIC!\n");
1859 	return 0;
1860 }
1861 
1862 int __init apic_force_enable(unsigned long addr)
1863 {
1864 	u32 h, l;
1865 
1866 	if (disable_apic)
1867 		return -1;
1868 
1869 	/*
1870 	 * Some BIOSes disable the local APIC in the APIC_BASE
1871 	 * MSR. This can only be done in software for Intel P6 or later
1872 	 * and AMD K7 (Model > 1) or later.
1873 	 */
1874 	if (boot_cpu_data.x86 >= 6) {
1875 		rdmsr(MSR_IA32_APICBASE, l, h);
1876 		if (!(l & MSR_IA32_APICBASE_ENABLE)) {
1877 			pr_info("Local APIC disabled by BIOS -- reenabling.\n");
1878 			l &= ~MSR_IA32_APICBASE_BASE;
1879 			l |= MSR_IA32_APICBASE_ENABLE | addr;
1880 			wrmsr(MSR_IA32_APICBASE, l, h);
1881 			enabled_via_apicbase = 1;
1882 		}
1883 	}
1884 	return apic_verify();
1885 }
1886 
1887 /*
1888  * Detect and initialize APIC
1889  */
1890 static int __init detect_init_APIC(void)
1891 {
1892 	/* Disabled by kernel option? */
1893 	if (disable_apic)
1894 		return -1;
1895 
1896 	switch (boot_cpu_data.x86_vendor) {
1897 	case X86_VENDOR_AMD:
1898 		if ((boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model > 1) ||
1899 		    (boot_cpu_data.x86 >= 15))
1900 			break;
1901 		goto no_apic;
1902 	case X86_VENDOR_INTEL:
1903 		if (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15 ||
1904 		    (boot_cpu_data.x86 == 5 && boot_cpu_has(X86_FEATURE_APIC)))
1905 			break;
1906 		goto no_apic;
1907 	default:
1908 		goto no_apic;
1909 	}
1910 
1911 	if (!boot_cpu_has(X86_FEATURE_APIC)) {
1912 		/*
1913 		 * Over-ride BIOS and try to enable the local APIC only if
1914 		 * "lapic" specified.
1915 		 */
1916 		if (!force_enable_local_apic) {
1917 			pr_info("Local APIC disabled by BIOS -- "
1918 				"you can enable it with \"lapic\"\n");
1919 			return -1;
1920 		}
1921 		if (apic_force_enable(APIC_DEFAULT_PHYS_BASE))
1922 			return -1;
1923 	} else {
1924 		if (apic_verify())
1925 			return -1;
1926 	}
1927 
1928 	apic_pm_activate();
1929 
1930 	return 0;
1931 
1932 no_apic:
1933 	pr_info("No local APIC present or hardware disabled\n");
1934 	return -1;
1935 }
1936 #endif
1937 
1938 /**
1939  * init_apic_mappings - initialize APIC mappings
1940  */
1941 void __init init_apic_mappings(void)
1942 {
1943 	unsigned int new_apicid;
1944 
1945 	apic_check_deadline_errata();
1946 
1947 	if (x2apic_mode) {
1948 		boot_cpu_physical_apicid = read_apic_id();
1949 		return;
1950 	}
1951 
1952 	/* If no local APIC can be found return early */
1953 	if (!smp_found_config && detect_init_APIC()) {
1954 		/* lets NOP'ify apic operations */
1955 		pr_info("APIC: disable apic facility\n");
1956 		apic_disable();
1957 	} else {
1958 		apic_phys = mp_lapic_addr;
1959 
1960 		/*
1961 		 * If the system has ACPI MADT tables or MP info, the LAPIC
1962 		 * address is already registered.
1963 		 */
1964 		if (!acpi_lapic && !smp_found_config)
1965 			register_lapic_address(apic_phys);
1966 	}
1967 
1968 	/*
1969 	 * Fetch the APIC ID of the BSP in case we have a
1970 	 * default configuration (or the MP table is broken).
1971 	 */
1972 	new_apicid = read_apic_id();
1973 	if (boot_cpu_physical_apicid != new_apicid) {
1974 		boot_cpu_physical_apicid = new_apicid;
1975 		/*
1976 		 * yeah -- we lie about apic_version
1977 		 * in case if apic was disabled via boot option
1978 		 * but it's not a problem for SMP compiled kernel
1979 		 * since apic_intr_mode_select is prepared for such
1980 		 * a case and disable smp mode
1981 		 */
1982 		boot_cpu_apic_version = GET_APIC_VERSION(apic_read(APIC_LVR));
1983 	}
1984 }
1985 
1986 void __init register_lapic_address(unsigned long address)
1987 {
1988 	mp_lapic_addr = address;
1989 
1990 	if (!x2apic_mode) {
1991 		set_fixmap_nocache(FIX_APIC_BASE, address);
1992 		apic_printk(APIC_VERBOSE, "mapped APIC to %16lx (%16lx)\n",
1993 			    APIC_BASE, address);
1994 	}
1995 	if (boot_cpu_physical_apicid == -1U) {
1996 		boot_cpu_physical_apicid  = read_apic_id();
1997 		boot_cpu_apic_version = GET_APIC_VERSION(apic_read(APIC_LVR));
1998 	}
1999 }
2000 
2001 /*
2002  * Local APIC interrupts
2003  */
2004 
2005 /*
2006  * This interrupt should _never_ happen with our APIC/SMP architecture
2007  */
2008 __visible void __irq_entry smp_spurious_interrupt(struct pt_regs *regs)
2009 {
2010 	u8 vector = ~regs->orig_ax;
2011 	u32 v;
2012 
2013 	entering_irq();
2014 	trace_spurious_apic_entry(vector);
2015 
2016 	/*
2017 	 * Check if this really is a spurious interrupt and ACK it
2018 	 * if it is a vectored one.  Just in case...
2019 	 * Spurious interrupts should not be ACKed.
2020 	 */
2021 	v = apic_read(APIC_ISR + ((vector & ~0x1f) >> 1));
2022 	if (v & (1 << (vector & 0x1f)))
2023 		ack_APIC_irq();
2024 
2025 	inc_irq_stat(irq_spurious_count);
2026 
2027 	/* see sw-dev-man vol 3, chapter 7.4.13.5 */
2028 	pr_info("spurious APIC interrupt through vector %02x on CPU#%d, "
2029 		"should never happen.\n", vector, smp_processor_id());
2030 
2031 	trace_spurious_apic_exit(vector);
2032 	exiting_irq();
2033 }
2034 
2035 /*
2036  * This interrupt should never happen with our APIC/SMP architecture
2037  */
2038 __visible void __irq_entry smp_error_interrupt(struct pt_regs *regs)
2039 {
2040 	static const char * const error_interrupt_reason[] = {
2041 		"Send CS error",		/* APIC Error Bit 0 */
2042 		"Receive CS error",		/* APIC Error Bit 1 */
2043 		"Send accept error",		/* APIC Error Bit 2 */
2044 		"Receive accept error",		/* APIC Error Bit 3 */
2045 		"Redirectable IPI",		/* APIC Error Bit 4 */
2046 		"Send illegal vector",		/* APIC Error Bit 5 */
2047 		"Received illegal vector",	/* APIC Error Bit 6 */
2048 		"Illegal register address",	/* APIC Error Bit 7 */
2049 	};
2050 	u32 v, i = 0;
2051 
2052 	entering_irq();
2053 	trace_error_apic_entry(ERROR_APIC_VECTOR);
2054 
2055 	/* First tickle the hardware, only then report what went on. -- REW */
2056 	if (lapic_get_maxlvt() > 3)	/* Due to the Pentium erratum 3AP. */
2057 		apic_write(APIC_ESR, 0);
2058 	v = apic_read(APIC_ESR);
2059 	ack_APIC_irq();
2060 	atomic_inc(&irq_err_count);
2061 
2062 	apic_printk(APIC_DEBUG, KERN_DEBUG "APIC error on CPU%d: %02x",
2063 		    smp_processor_id(), v);
2064 
2065 	v &= 0xff;
2066 	while (v) {
2067 		if (v & 0x1)
2068 			apic_printk(APIC_DEBUG, KERN_CONT " : %s", error_interrupt_reason[i]);
2069 		i++;
2070 		v >>= 1;
2071 	}
2072 
2073 	apic_printk(APIC_DEBUG, KERN_CONT "\n");
2074 
2075 	trace_error_apic_exit(ERROR_APIC_VECTOR);
2076 	exiting_irq();
2077 }
2078 
2079 /**
2080  * connect_bsp_APIC - attach the APIC to the interrupt system
2081  */
2082 static void __init connect_bsp_APIC(void)
2083 {
2084 #ifdef CONFIG_X86_32
2085 	if (pic_mode) {
2086 		/*
2087 		 * Do not trust the local APIC being empty at bootup.
2088 		 */
2089 		clear_local_APIC();
2090 		/*
2091 		 * PIC mode, enable APIC mode in the IMCR, i.e.  connect BSP's
2092 		 * local APIC to INT and NMI lines.
2093 		 */
2094 		apic_printk(APIC_VERBOSE, "leaving PIC mode, "
2095 				"enabling APIC mode.\n");
2096 		imcr_pic_to_apic();
2097 	}
2098 #endif
2099 }
2100 
2101 /**
2102  * disconnect_bsp_APIC - detach the APIC from the interrupt system
2103  * @virt_wire_setup:	indicates, whether virtual wire mode is selected
2104  *
2105  * Virtual wire mode is necessary to deliver legacy interrupts even when the
2106  * APIC is disabled.
2107  */
2108 void disconnect_bsp_APIC(int virt_wire_setup)
2109 {
2110 	unsigned int value;
2111 
2112 #ifdef CONFIG_X86_32
2113 	if (pic_mode) {
2114 		/*
2115 		 * Put the board back into PIC mode (has an effect only on
2116 		 * certain older boards).  Note that APIC interrupts, including
2117 		 * IPIs, won't work beyond this point!  The only exception are
2118 		 * INIT IPIs.
2119 		 */
2120 		apic_printk(APIC_VERBOSE, "disabling APIC mode, "
2121 				"entering PIC mode.\n");
2122 		imcr_apic_to_pic();
2123 		return;
2124 	}
2125 #endif
2126 
2127 	/* Go back to Virtual Wire compatibility mode */
2128 
2129 	/* For the spurious interrupt use vector F, and enable it */
2130 	value = apic_read(APIC_SPIV);
2131 	value &= ~APIC_VECTOR_MASK;
2132 	value |= APIC_SPIV_APIC_ENABLED;
2133 	value |= 0xf;
2134 	apic_write(APIC_SPIV, value);
2135 
2136 	if (!virt_wire_setup) {
2137 		/*
2138 		 * For LVT0 make it edge triggered, active high,
2139 		 * external and enabled
2140 		 */
2141 		value = apic_read(APIC_LVT0);
2142 		value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
2143 			APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
2144 			APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
2145 		value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
2146 		value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT);
2147 		apic_write(APIC_LVT0, value);
2148 	} else {
2149 		/* Disable LVT0 */
2150 		apic_write(APIC_LVT0, APIC_LVT_MASKED);
2151 	}
2152 
2153 	/*
2154 	 * For LVT1 make it edge triggered, active high,
2155 	 * nmi and enabled
2156 	 */
2157 	value = apic_read(APIC_LVT1);
2158 	value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
2159 			APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
2160 			APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
2161 	value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
2162 	value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
2163 	apic_write(APIC_LVT1, value);
2164 }
2165 
2166 /*
2167  * The number of allocated logical CPU IDs. Since logical CPU IDs are allocated
2168  * contiguously, it equals to current allocated max logical CPU ID plus 1.
2169  * All allocated CPU IDs should be in the [0, nr_logical_cpuids) range,
2170  * so the maximum of nr_logical_cpuids is nr_cpu_ids.
2171  *
2172  * NOTE: Reserve 0 for BSP.
2173  */
2174 static int nr_logical_cpuids = 1;
2175 
2176 /*
2177  * Used to store mapping between logical CPU IDs and APIC IDs.
2178  */
2179 static int cpuid_to_apicid[] = {
2180 	[0 ... NR_CPUS - 1] = -1,
2181 };
2182 
2183 /*
2184  * Should use this API to allocate logical CPU IDs to keep nr_logical_cpuids
2185  * and cpuid_to_apicid[] synchronized.
2186  */
2187 static int allocate_logical_cpuid(int apicid)
2188 {
2189 	int i;
2190 
2191 	/*
2192 	 * cpuid <-> apicid mapping is persistent, so when a cpu is up,
2193 	 * check if the kernel has allocated a cpuid for it.
2194 	 */
2195 	for (i = 0; i < nr_logical_cpuids; i++) {
2196 		if (cpuid_to_apicid[i] == apicid)
2197 			return i;
2198 	}
2199 
2200 	/* Allocate a new cpuid. */
2201 	if (nr_logical_cpuids >= nr_cpu_ids) {
2202 		WARN_ONCE(1, "APIC: NR_CPUS/possible_cpus limit of %u reached. "
2203 			     "Processor %d/0x%x and the rest are ignored.\n",
2204 			     nr_cpu_ids, nr_logical_cpuids, apicid);
2205 		return -EINVAL;
2206 	}
2207 
2208 	cpuid_to_apicid[nr_logical_cpuids] = apicid;
2209 	return nr_logical_cpuids++;
2210 }
2211 
2212 int generic_processor_info(int apicid, int version)
2213 {
2214 	int cpu, max = nr_cpu_ids;
2215 	bool boot_cpu_detected = physid_isset(boot_cpu_physical_apicid,
2216 				phys_cpu_present_map);
2217 
2218 	/*
2219 	 * boot_cpu_physical_apicid is designed to have the apicid
2220 	 * returned by read_apic_id(), i.e, the apicid of the
2221 	 * currently booting-up processor. However, on some platforms,
2222 	 * it is temporarily modified by the apicid reported as BSP
2223 	 * through MP table. Concretely:
2224 	 *
2225 	 * - arch/x86/kernel/mpparse.c: MP_processor_info()
2226 	 * - arch/x86/mm/amdtopology.c: amd_numa_init()
2227 	 *
2228 	 * This function is executed with the modified
2229 	 * boot_cpu_physical_apicid. So, disabled_cpu_apicid kernel
2230 	 * parameter doesn't work to disable APs on kdump 2nd kernel.
2231 	 *
2232 	 * Since fixing handling of boot_cpu_physical_apicid requires
2233 	 * another discussion and tests on each platform, we leave it
2234 	 * for now and here we use read_apic_id() directly in this
2235 	 * function, generic_processor_info().
2236 	 */
2237 	if (disabled_cpu_apicid != BAD_APICID &&
2238 	    disabled_cpu_apicid != read_apic_id() &&
2239 	    disabled_cpu_apicid == apicid) {
2240 		int thiscpu = num_processors + disabled_cpus;
2241 
2242 		pr_warning("APIC: Disabling requested cpu."
2243 			   " Processor %d/0x%x ignored.\n",
2244 			   thiscpu, apicid);
2245 
2246 		disabled_cpus++;
2247 		return -ENODEV;
2248 	}
2249 
2250 	/*
2251 	 * If boot cpu has not been detected yet, then only allow upto
2252 	 * nr_cpu_ids - 1 processors and keep one slot free for boot cpu
2253 	 */
2254 	if (!boot_cpu_detected && num_processors >= nr_cpu_ids - 1 &&
2255 	    apicid != boot_cpu_physical_apicid) {
2256 		int thiscpu = max + disabled_cpus - 1;
2257 
2258 		pr_warning(
2259 			"APIC: NR_CPUS/possible_cpus limit of %i almost"
2260 			" reached. Keeping one slot for boot cpu."
2261 			"  Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
2262 
2263 		disabled_cpus++;
2264 		return -ENODEV;
2265 	}
2266 
2267 	if (num_processors >= nr_cpu_ids) {
2268 		int thiscpu = max + disabled_cpus;
2269 
2270 		pr_warning("APIC: NR_CPUS/possible_cpus limit of %i "
2271 			   "reached. Processor %d/0x%x ignored.\n",
2272 			   max, thiscpu, apicid);
2273 
2274 		disabled_cpus++;
2275 		return -EINVAL;
2276 	}
2277 
2278 	if (apicid == boot_cpu_physical_apicid) {
2279 		/*
2280 		 * x86_bios_cpu_apicid is required to have processors listed
2281 		 * in same order as logical cpu numbers. Hence the first
2282 		 * entry is BSP, and so on.
2283 		 * boot_cpu_init() already hold bit 0 in cpu_present_mask
2284 		 * for BSP.
2285 		 */
2286 		cpu = 0;
2287 
2288 		/* Logical cpuid 0 is reserved for BSP. */
2289 		cpuid_to_apicid[0] = apicid;
2290 	} else {
2291 		cpu = allocate_logical_cpuid(apicid);
2292 		if (cpu < 0) {
2293 			disabled_cpus++;
2294 			return -EINVAL;
2295 		}
2296 	}
2297 
2298 	/*
2299 	 * Validate version
2300 	 */
2301 	if (version == 0x0) {
2302 		pr_warning("BIOS bug: APIC version is 0 for CPU %d/0x%x, fixing up to 0x10\n",
2303 			   cpu, apicid);
2304 		version = 0x10;
2305 	}
2306 
2307 	if (version != boot_cpu_apic_version) {
2308 		pr_warning("BIOS bug: APIC version mismatch, boot CPU: %x, CPU %d: version %x\n",
2309 			boot_cpu_apic_version, cpu, version);
2310 	}
2311 
2312 	if (apicid > max_physical_apicid)
2313 		max_physical_apicid = apicid;
2314 
2315 #if defined(CONFIG_SMP) || defined(CONFIG_X86_64)
2316 	early_per_cpu(x86_cpu_to_apicid, cpu) = apicid;
2317 	early_per_cpu(x86_bios_cpu_apicid, cpu) = apicid;
2318 #endif
2319 #ifdef CONFIG_X86_32
2320 	early_per_cpu(x86_cpu_to_logical_apicid, cpu) =
2321 		apic->x86_32_early_logical_apicid(cpu);
2322 #endif
2323 	set_cpu_possible(cpu, true);
2324 	physid_set(apicid, phys_cpu_present_map);
2325 	set_cpu_present(cpu, true);
2326 	num_processors++;
2327 
2328 	return cpu;
2329 }
2330 
2331 int hard_smp_processor_id(void)
2332 {
2333 	return read_apic_id();
2334 }
2335 
2336 /*
2337  * Override the generic EOI implementation with an optimized version.
2338  * Only called during early boot when only one CPU is active and with
2339  * interrupts disabled, so we know this does not race with actual APIC driver
2340  * use.
2341  */
2342 void __init apic_set_eoi_write(void (*eoi_write)(u32 reg, u32 v))
2343 {
2344 	struct apic **drv;
2345 
2346 	for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
2347 		/* Should happen once for each apic */
2348 		WARN_ON((*drv)->eoi_write == eoi_write);
2349 		(*drv)->native_eoi_write = (*drv)->eoi_write;
2350 		(*drv)->eoi_write = eoi_write;
2351 	}
2352 }
2353 
2354 static void __init apic_bsp_up_setup(void)
2355 {
2356 #ifdef CONFIG_X86_64
2357 	apic_write(APIC_ID, apic->set_apic_id(boot_cpu_physical_apicid));
2358 #else
2359 	/*
2360 	 * Hack: In case of kdump, after a crash, kernel might be booting
2361 	 * on a cpu with non-zero lapic id. But boot_cpu_physical_apicid
2362 	 * might be zero if read from MP tables. Get it from LAPIC.
2363 	 */
2364 # ifdef CONFIG_CRASH_DUMP
2365 	boot_cpu_physical_apicid = read_apic_id();
2366 # endif
2367 #endif
2368 	physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
2369 }
2370 
2371 /**
2372  * apic_bsp_setup - Setup function for local apic and io-apic
2373  * @upmode:		Force UP mode (for APIC_init_uniprocessor)
2374  *
2375  * Returns:
2376  * apic_id of BSP APIC
2377  */
2378 void __init apic_bsp_setup(bool upmode)
2379 {
2380 	connect_bsp_APIC();
2381 	if (upmode)
2382 		apic_bsp_up_setup();
2383 	setup_local_APIC();
2384 
2385 	enable_IO_APIC();
2386 	end_local_APIC_setup();
2387 	irq_remap_enable_fault_handling();
2388 	setup_IO_APIC();
2389 }
2390 
2391 #ifdef CONFIG_UP_LATE_INIT
2392 void __init up_late_init(void)
2393 {
2394 	if (apic_intr_mode == APIC_PIC)
2395 		return;
2396 
2397 	/* Setup local timer */
2398 	x86_init.timers.setup_percpu_clockev();
2399 }
2400 #endif
2401 
2402 /*
2403  * Power management
2404  */
2405 #ifdef CONFIG_PM
2406 
2407 static struct {
2408 	/*
2409 	 * 'active' is true if the local APIC was enabled by us and
2410 	 * not the BIOS; this signifies that we are also responsible
2411 	 * for disabling it before entering apm/acpi suspend
2412 	 */
2413 	int active;
2414 	/* r/w apic fields */
2415 	unsigned int apic_id;
2416 	unsigned int apic_taskpri;
2417 	unsigned int apic_ldr;
2418 	unsigned int apic_dfr;
2419 	unsigned int apic_spiv;
2420 	unsigned int apic_lvtt;
2421 	unsigned int apic_lvtpc;
2422 	unsigned int apic_lvt0;
2423 	unsigned int apic_lvt1;
2424 	unsigned int apic_lvterr;
2425 	unsigned int apic_tmict;
2426 	unsigned int apic_tdcr;
2427 	unsigned int apic_thmr;
2428 	unsigned int apic_cmci;
2429 } apic_pm_state;
2430 
2431 static int lapic_suspend(void)
2432 {
2433 	unsigned long flags;
2434 	int maxlvt;
2435 
2436 	if (!apic_pm_state.active)
2437 		return 0;
2438 
2439 	maxlvt = lapic_get_maxlvt();
2440 
2441 	apic_pm_state.apic_id = apic_read(APIC_ID);
2442 	apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
2443 	apic_pm_state.apic_ldr = apic_read(APIC_LDR);
2444 	apic_pm_state.apic_dfr = apic_read(APIC_DFR);
2445 	apic_pm_state.apic_spiv = apic_read(APIC_SPIV);
2446 	apic_pm_state.apic_lvtt = apic_read(APIC_LVTT);
2447 	if (maxlvt >= 4)
2448 		apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC);
2449 	apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0);
2450 	apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1);
2451 	apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
2452 	apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
2453 	apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
2454 #ifdef CONFIG_X86_THERMAL_VECTOR
2455 	if (maxlvt >= 5)
2456 		apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
2457 #endif
2458 #ifdef CONFIG_X86_MCE_INTEL
2459 	if (maxlvt >= 6)
2460 		apic_pm_state.apic_cmci = apic_read(APIC_LVTCMCI);
2461 #endif
2462 
2463 	local_irq_save(flags);
2464 	disable_local_APIC();
2465 
2466 	irq_remapping_disable();
2467 
2468 	local_irq_restore(flags);
2469 	return 0;
2470 }
2471 
2472 static void lapic_resume(void)
2473 {
2474 	unsigned int l, h;
2475 	unsigned long flags;
2476 	int maxlvt;
2477 
2478 	if (!apic_pm_state.active)
2479 		return;
2480 
2481 	local_irq_save(flags);
2482 
2483 	/*
2484 	 * IO-APIC and PIC have their own resume routines.
2485 	 * We just mask them here to make sure the interrupt
2486 	 * subsystem is completely quiet while we enable x2apic
2487 	 * and interrupt-remapping.
2488 	 */
2489 	mask_ioapic_entries();
2490 	legacy_pic->mask_all();
2491 
2492 	if (x2apic_mode) {
2493 		__x2apic_enable();
2494 	} else {
2495 		/*
2496 		 * Make sure the APICBASE points to the right address
2497 		 *
2498 		 * FIXME! This will be wrong if we ever support suspend on
2499 		 * SMP! We'll need to do this as part of the CPU restore!
2500 		 */
2501 		if (boot_cpu_data.x86 >= 6) {
2502 			rdmsr(MSR_IA32_APICBASE, l, h);
2503 			l &= ~MSR_IA32_APICBASE_BASE;
2504 			l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr;
2505 			wrmsr(MSR_IA32_APICBASE, l, h);
2506 		}
2507 	}
2508 
2509 	maxlvt = lapic_get_maxlvt();
2510 	apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
2511 	apic_write(APIC_ID, apic_pm_state.apic_id);
2512 	apic_write(APIC_DFR, apic_pm_state.apic_dfr);
2513 	apic_write(APIC_LDR, apic_pm_state.apic_ldr);
2514 	apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri);
2515 	apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
2516 	apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
2517 	apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
2518 #ifdef CONFIG_X86_THERMAL_VECTOR
2519 	if (maxlvt >= 5)
2520 		apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr);
2521 #endif
2522 #ifdef CONFIG_X86_MCE_INTEL
2523 	if (maxlvt >= 6)
2524 		apic_write(APIC_LVTCMCI, apic_pm_state.apic_cmci);
2525 #endif
2526 	if (maxlvt >= 4)
2527 		apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
2528 	apic_write(APIC_LVTT, apic_pm_state.apic_lvtt);
2529 	apic_write(APIC_TDCR, apic_pm_state.apic_tdcr);
2530 	apic_write(APIC_TMICT, apic_pm_state.apic_tmict);
2531 	apic_write(APIC_ESR, 0);
2532 	apic_read(APIC_ESR);
2533 	apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr);
2534 	apic_write(APIC_ESR, 0);
2535 	apic_read(APIC_ESR);
2536 
2537 	irq_remapping_reenable(x2apic_mode);
2538 
2539 	local_irq_restore(flags);
2540 }
2541 
2542 /*
2543  * This device has no shutdown method - fully functioning local APICs
2544  * are needed on every CPU up until machine_halt/restart/poweroff.
2545  */
2546 
2547 static struct syscore_ops lapic_syscore_ops = {
2548 	.resume		= lapic_resume,
2549 	.suspend	= lapic_suspend,
2550 };
2551 
2552 static void apic_pm_activate(void)
2553 {
2554 	apic_pm_state.active = 1;
2555 }
2556 
2557 static int __init init_lapic_sysfs(void)
2558 {
2559 	/* XXX: remove suspend/resume procs if !apic_pm_state.active? */
2560 	if (boot_cpu_has(X86_FEATURE_APIC))
2561 		register_syscore_ops(&lapic_syscore_ops);
2562 
2563 	return 0;
2564 }
2565 
2566 /* local apic needs to resume before other devices access its registers. */
2567 core_initcall(init_lapic_sysfs);
2568 
2569 #else	/* CONFIG_PM */
2570 
2571 static void apic_pm_activate(void) { }
2572 
2573 #endif	/* CONFIG_PM */
2574 
2575 #ifdef CONFIG_X86_64
2576 
2577 static int multi_checked;
2578 static int multi;
2579 
2580 static int set_multi(const struct dmi_system_id *d)
2581 {
2582 	if (multi)
2583 		return 0;
2584 	pr_info("APIC: %s detected, Multi Chassis\n", d->ident);
2585 	multi = 1;
2586 	return 0;
2587 }
2588 
2589 static const struct dmi_system_id multi_dmi_table[] = {
2590 	{
2591 		.callback = set_multi,
2592 		.ident = "IBM System Summit2",
2593 		.matches = {
2594 			DMI_MATCH(DMI_SYS_VENDOR, "IBM"),
2595 			DMI_MATCH(DMI_PRODUCT_NAME, "Summit2"),
2596 		},
2597 	},
2598 	{}
2599 };
2600 
2601 static void dmi_check_multi(void)
2602 {
2603 	if (multi_checked)
2604 		return;
2605 
2606 	dmi_check_system(multi_dmi_table);
2607 	multi_checked = 1;
2608 }
2609 
2610 /*
2611  * apic_is_clustered_box() -- Check if we can expect good TSC
2612  *
2613  * Thus far, the major user of this is IBM's Summit2 series:
2614  * Clustered boxes may have unsynced TSC problems if they are
2615  * multi-chassis.
2616  * Use DMI to check them
2617  */
2618 int apic_is_clustered_box(void)
2619 {
2620 	dmi_check_multi();
2621 	return multi;
2622 }
2623 #endif
2624 
2625 /*
2626  * APIC command line parameters
2627  */
2628 static int __init setup_disableapic(char *arg)
2629 {
2630 	disable_apic = 1;
2631 	setup_clear_cpu_cap(X86_FEATURE_APIC);
2632 	return 0;
2633 }
2634 early_param("disableapic", setup_disableapic);
2635 
2636 /* same as disableapic, for compatibility */
2637 static int __init setup_nolapic(char *arg)
2638 {
2639 	return setup_disableapic(arg);
2640 }
2641 early_param("nolapic", setup_nolapic);
2642 
2643 static int __init parse_lapic_timer_c2_ok(char *arg)
2644 {
2645 	local_apic_timer_c2_ok = 1;
2646 	return 0;
2647 }
2648 early_param("lapic_timer_c2_ok", parse_lapic_timer_c2_ok);
2649 
2650 static int __init parse_disable_apic_timer(char *arg)
2651 {
2652 	disable_apic_timer = 1;
2653 	return 0;
2654 }
2655 early_param("noapictimer", parse_disable_apic_timer);
2656 
2657 static int __init parse_nolapic_timer(char *arg)
2658 {
2659 	disable_apic_timer = 1;
2660 	return 0;
2661 }
2662 early_param("nolapic_timer", parse_nolapic_timer);
2663 
2664 static int __init apic_set_verbosity(char *arg)
2665 {
2666 	if (!arg)  {
2667 #ifdef CONFIG_X86_64
2668 		skip_ioapic_setup = 0;
2669 		return 0;
2670 #endif
2671 		return -EINVAL;
2672 	}
2673 
2674 	if (strcmp("debug", arg) == 0)
2675 		apic_verbosity = APIC_DEBUG;
2676 	else if (strcmp("verbose", arg) == 0)
2677 		apic_verbosity = APIC_VERBOSE;
2678 #ifdef CONFIG_X86_64
2679 	else {
2680 		pr_warning("APIC Verbosity level %s not recognised"
2681 			" use apic=verbose or apic=debug\n", arg);
2682 		return -EINVAL;
2683 	}
2684 #endif
2685 
2686 	return 0;
2687 }
2688 early_param("apic", apic_set_verbosity);
2689 
2690 static int __init lapic_insert_resource(void)
2691 {
2692 	if (!apic_phys)
2693 		return -1;
2694 
2695 	/* Put local APIC into the resource map. */
2696 	lapic_resource.start = apic_phys;
2697 	lapic_resource.end = lapic_resource.start + PAGE_SIZE - 1;
2698 	insert_resource(&iomem_resource, &lapic_resource);
2699 
2700 	return 0;
2701 }
2702 
2703 /*
2704  * need call insert after e820__reserve_resources()
2705  * that is using request_resource
2706  */
2707 late_initcall(lapic_insert_resource);
2708 
2709 static int __init apic_set_disabled_cpu_apicid(char *arg)
2710 {
2711 	if (!arg || !get_option(&arg, &disabled_cpu_apicid))
2712 		return -EINVAL;
2713 
2714 	return 0;
2715 }
2716 early_param("disable_cpu_apicid", apic_set_disabled_cpu_apicid);
2717 
2718 static int __init apic_set_extnmi(char *arg)
2719 {
2720 	if (!arg)
2721 		return -EINVAL;
2722 
2723 	if (!strncmp("all", arg, 3))
2724 		apic_extnmi = APIC_EXTNMI_ALL;
2725 	else if (!strncmp("none", arg, 4))
2726 		apic_extnmi = APIC_EXTNMI_NONE;
2727 	else if (!strncmp("bsp", arg, 3))
2728 		apic_extnmi = APIC_EXTNMI_BSP;
2729 	else {
2730 		pr_warn("Unknown external NMI delivery mode `%s' ignored\n", arg);
2731 		return -EINVAL;
2732 	}
2733 
2734 	return 0;
2735 }
2736 early_param("apic_extnmi", apic_set_extnmi);
2737