aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/kernel/apic_64.c
blob: 42bf69f8bc8e3a38d5756a7c35299b7dfd577444 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
/*
 *	Local APIC handling, local APIC timers
 *
 *	(c) 1999, 2000 Ingo Molnar <mingo@redhat.com>
 *
 *	Fixes
 *	Maciej W. Rozycki	:	Bits for genuine 82489DX APICs;
 *					thanks to Eric Gilmore
 *					and Rolf G. Tews
 *					for testing these extensively.
 *	Maciej W. Rozycki	:	Various updates and fixes.
 *	Mikael Pettersson	:	Power Management for UP-APIC.
 *	Pavel Machek and
 *	Mikael Pettersson	:	PM converted to driver model.
 */

#include <linux/init.h>

#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/bootmem.h>
#include <linux/interrupt.h>
#include <linux/mc146818rtc.h>
#include <linux/kernel_stat.h>
#include <linux/sysdev.h>
#include <linux/ioport.h>
#include <linux/clockchips.h>
#include <linux/acpi_pmtmr.h>
#include <linux/module.h>

#include <asm/atomic.h>
#include <asm/smp.h>
#include <asm/mtrr.h>
#include <asm/mpspec.h>
#include <asm/hpet.h>
#include <asm/pgalloc.h>
#include <asm/nmi.h>
#include <asm/idle.h>
#include <asm/proto.h>
#include <asm/timex.h>
#include <asm/apic.h>

#include <mach_ipi.h>
#include <mach_apic.h>

static int disable_apic_timer __cpuinitdata;
static int apic_calibrate_pmtmr __initdata;
int disable_apic;

/* Local APIC timer works in C2 */
int local_apic_timer_c2_ok;
EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);

/*
 * Debug level, exported for io_apic.c
 */
unsigned int apic_verbosity;

/* Have we found an MP table */
int smp_found_config;

static struct resource lapic_resource = {
	.name = "Local APIC",
	.flags = IORESOURCE_MEM | IORESOURCE_BUSY,
};

static unsigned int calibration_result;

static int lapic_next_event(unsigned long delta,
			    struct clock_event_device *evt);
static void lapic_timer_setup(enum clock_event_mode mode,
			      struct clock_event_device *evt);
static void lapic_timer_broadcast(cpumask_t mask);
static void apic_pm_activate(void);

static struct clock_event_device lapic_clockevent = {
	.name		= "lapic",
	.features	= CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT
			| CLOCK_EVT_FEAT_C3STOP | CLOCK_EVT_FEAT_DUMMY,
	.shift		= 32,
	.set_mode	= lapic_timer_setup,
	.set_next_event	= lapic_next_event,
	.broadcast	= lapic_timer_broadcast,
	.rating		= 100,
	.irq		= -1,
};
static DEFINE_PER_CPU(struct clock_event_device, lapic_events);

static unsigned long apic_phys;

unsigned long mp_lapic_addr;

unsigned int __cpuinitdata maxcpus = NR_CPUS;
/*
 * Get the LAPIC version
 */
static inline int lapic_get_version(void)
{
	return GET_APIC_VERSION(apic_read(APIC_LVR));
}

/*
 * Check, if the APIC is integrated or a seperate chip
 */
static inline int lapic_is_integrated(void)
{
	return 1;
}

/*
 * Check, whether this is a modern or a first generation APIC
 */
static int modern_apic(void)
{
	/* AMD systems use old APIC versions, so check the CPU */
	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
	    boot_cpu_data.x86 >= 0xf)
		return 1;
	return lapic_get_version() >= 0x14;
}

void apic_wait_icr_idle(void)
{
	while (apic_read(APIC_ICR) & APIC_ICR_BUSY)
		cpu_relax();
}

u32 safe_apic_wait_icr_idle(void)
{
	u32 send_status;
	int timeout;

	timeout = 0;
	do {
		send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
		if (!send_status)
			break;
		udelay(100);
	} while (timeout++ < 1000);

	return send_status;
}

/**
 * enable_NMI_through_LVT0 - enable NMI through local vector table 0
 */
void __cpuinit enable_NMI_through_LVT0(void)
{
	unsigned int v;

	/* unmask and set to NMI */
	v = APIC_DM_NMI;
	apic_write(APIC_LVT0, v);
}

/**
 * lapic_get_maxlvt - get the maximum number of local vector table entries
 */
int lapic_get_maxlvt(void)
{
	unsigned int v, maxlvt;

	v = apic_read(APIC_LVR);
	maxlvt = GET_APIC_MAXLVT(v);
	return maxlvt;
}

/*
 * This function sets up the local APIC timer, with a timeout of
 * 'clocks' APIC bus clock. During calibration we actually call
 * this function twice on the boot CPU, once with a bogus timeout
 * value, second time for real. The other (noncalibrating) CPUs
 * call this function only once, with the real, calibrated value.
 *
 * We do reads before writes even if unnecessary, to get around the
 * P5 APIC double write bug.
 */

static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen)
{
	unsigned int lvtt_value, tmp_value;

	lvtt_value = LOCAL_TIMER_VECTOR;
	if (!oneshot)
		lvtt_value |= APIC_LVT_TIMER_PERIODIC;
	if (!irqen)
		lvtt_value |= APIC_LVT_MASKED;

	apic_write(APIC_LVTT, lvtt_value);

	/*
	 * Divide PICLK by 16
	 */
	tmp_value = apic_read(APIC_TDCR);
	apic_write(APIC_TDCR, (tmp_value
				& ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE))
				| APIC_TDR_DIV_16);

	if (!oneshot)
		apic_write(APIC_TMICT, clocks);
}

/*
 * Setup extended LVT, AMD specific (K8, family 10h)
 *
 * Vector mappings are hard coded. On K8 only offset 0 (APIC500) and
 * MCE interrupts are supported. Thus MCE offset must be set to 0.
 *
 * If mask=1, the LVT entry does not generate interrupts while mask=0
 * enables the vector. See also the BKDGs.
 */

#define APIC_EILVT_LVTOFF_MCE 0
#define APIC_EILVT_LVTOFF_IBS 1

static void setup_APIC_eilvt(u8 lvt_off, u8 vector, u8 msg_type, u8 mask)
{
	unsigned long reg = (lvt_off << 4) + APIC_EILVT0;
	unsigned int  v   = (mask << 16) | (msg_type << 8) | vector;

	apic_write(reg, v);
}

u8 setup_APIC_eilvt_mce(u8 vector, u8 msg_type, u8 mask)
{
	setup_APIC_eilvt(APIC_EILVT_LVTOFF_MCE, vector, msg_type, mask);
	return APIC_EILVT_LVTOFF_MCE;
}

u8 setup_APIC_eilvt_ibs(u8 vector, u8 msg_type, u8 mask)
{
	setup_APIC_eilvt(APIC_EILVT_LVTOFF_IBS, vector, msg_type, mask);
	return APIC_EILVT_LVTOFF_IBS;
}

/*
 * Program the next event, relative to now
 */
static int lapic_next_event(unsigned long delta,
			    struct clock_event_device *evt)
{
	apic_write(APIC_TMICT, delta);
	return 0;
}

/*
 * Setup the lapic timer in periodic or oneshot mode
 */
static void lapic_timer_setup(enum clock_event_mode mode,
			      struct clock_event_device *evt)
{
	unsigned long flags;
	unsigned int v;

	/* Lapic used as dummy for broadcast ? */
	if (evt->features & CLOCK_EVT_FEAT_DUMMY)
		return;

	local_irq_save(flags);

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
	case CLOCK_EVT_MODE_ONESHOT:
		__setup_APIC_LVTT(calibration_result,
				  mode != CLOCK_EVT_MODE_PERIODIC, 1);
		break;
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
		v = apic_read(APIC_LVTT);
		v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
		apic_write(APIC_LVTT, v);
		break;
	case CLOCK_EVT_MODE_RESUME:
		/* Nothing to do here */
		break;
	}

	local_irq_restore(flags);
}

/*
 * Local APIC timer broadcast function
 */
static void lapic_timer_broadcast(cpumask_t mask)
{
#ifdef CONFIG_SMP
	send_IPI_mask(mask, LOCAL_TIMER_VECTOR);
#endif
}

/*
 * Setup the local APIC timer for this CPU. Copy the initilized values
 * of the boot CPU and register the clock event in the framework.
 */
static void setup_APIC_timer(void)
{
	struct clock_event_device *levt = &__get_cpu_var(lapic_events);

	memcpy(levt, &lapic_clockevent, sizeof(*levt));
	levt->cpumask = cpumask_of_cpu(smp_processor_id());

	clockevents_register_device(levt);
}

/*
 * In this function we calibrate APIC bus clocks to the external
 * timer. Unfortunately we cannot use jiffies and the timer irq
 * to calibrate, since some later bootup code depends on getting
 * the first irq? Ugh.
 *
 * We want to do the calibration only once since we
 * want to have local timer irqs syncron. CPUs connected
 * by the same APIC bus have the very same bus frequency.
 * And we want to have irqs off anyways, no accidental
 * APIC irq that way.
 */

#define TICK_COUNT 100000000

static int __init calibrate_APIC_clock(void)
{
	unsigned apic, apic_start;
	unsigned long tsc, tsc_start;
	int result;

	local_irq_disable();

	/*
	 * Put whatever arbitrary (but long enough) timeout
	 * value into the APIC clock, we just want to get the
	 * counter running for calibration.
	 *
	 * No interrupt enable !
	 */
	__setup_APIC_LVTT(250000000, 0, 0);

	apic_start = apic_read(APIC_TMCCT);
#ifdef CONFIG_X86_PM_TIMER
	if (apic_calibrate_pmtmr && pmtmr_ioport) {
		pmtimer_wait(5000);  /* 5ms wait */
		apic = apic_read(APIC_TMCCT);
		result = (apic_start - apic) * 1000L / 5;
	} else
#endif
	{
		rdtscll(tsc_start);

		do {
			apic = apic_read(APIC_TMCCT);
			rdtscll(tsc);
		} while ((tsc - tsc_start) < TICK_COUNT &&
				(apic_start - apic) < TICK_COUNT);

		result = (apic_start - apic) * 1000L * tsc_khz /
					(tsc - tsc_start);
	}

	local_irq_enable();

	printk(KERN_DEBUG "APIC timer calibration result %d\n", result);

	printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n",
		result / 1000 / 1000, result / 1000 % 1000);

	/* Calculate the scaled math multiplication factor */
	lapic_clockevent.mult = div_sc(result, NSEC_PER_SEC,
				       lapic_clockevent.shift);
	lapic_clockevent.max_delta_ns =
		clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
	lapic_clockevent.min_delta_ns =
		clockevent_delta2ns(0xF, &lapic_clockevent);

	calibration_result = result / HZ;

	/*
	 * Do a sanity check on the APIC calibration result
	 */
	if (calibration_result < (1000000 / HZ)) {
		printk(KERN_WARNING
			"APIC frequency too slow, disabling apic timer\n");
		return -1;
	}

	return 0;
}

/*
 * Setup the boot APIC
 *
 * Calibrate and verify the result.
 */
void __init setup_boot_APIC_clock(void)
{
	/*
	 * The local apic timer can be disabled via the kernel commandline.
	 * Register the lapic timer as a dummy clock event source on SMP
	 * systems, so the broadcast mechanism is used. On UP systems simply
	 * ignore it.
	 */
	if (disable_apic_timer) {
		printk(KERN_INFO "Disabling APIC timer\n");
		/* No broadcast on UP ! */
		if (num_possible_cpus() > 1) {
			lapic_clockevent.mult = 1;
			setup_APIC_timer();
		}
		return;
	}

	printk(KERN_INFO "Using local APIC timer interrupts.\n");
	if (calibrate_APIC_clock()) {
		/* No broadcast on UP ! */
		if (num_possible_cpus() > 1)
			setup_APIC_timer();
		return;
	}

	/*
	 * If nmi_watchdog is set to IO_APIC, we need the
	 * PIT/HPET going.  Otherwise register lapic as a dummy
	 * device.
	 */
	if (nmi_watchdog != NMI_IO_APIC)
		lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
	else
		printk(KERN_WARNING "APIC timer registered as dummy,"
			" due to nmi_watchdog=%d!\n", nmi_watchdog);

	setup_APIC_timer();
}

void __cpuinit setup_secondary_APIC_clock(void)
{
	setup_APIC_timer();
}

/*
 * The guts of the apic timer interrupt
 */
static void local_apic_timer_interrupt(void)
{
	int cpu = smp_processor_id();
	struct clock_event_device *evt = &per_cpu(lapic_events, cpu);

	/*
	 * Normally we should not be here till LAPIC has been initialized but
	 * in some cases like kdump, its possible that there is a pending LAPIC
	 * timer interrupt from previous kernel's context and is delivered in
	 * new kernel the moment interrupts are enabled.
	 *
	 * Interrupts are enabled early and LAPIC is setup much later, hence
	 * its possible that when we get here evt->event_handler is NULL.
	 * Check for event_handler being NULL and discard the interrupt as
	 * spurious.
	 */
	if (!evt->event_handler) {
		printk(KERN_WARNING
		       "Spurious LAPIC timer interrupt on cpu %d\n", cpu);
		/* Switch it off */
		lapic_timer_setup(CLOCK_EVT_MODE_SHUTDOWN, evt);
		return;
	}

	/*
	 * the NMI deadlock-detector uses this.
	 */
	add_pda(apic_timer_irqs, 1);

	evt->event_handler(evt);
}

/*
 * Local APIC timer interrupt. This is the most natural way for doing
 * local interrupts, but local timer interrupts can be emulated by
 * broadcast interrupts too. [in case the hw doesn't support APIC timers]
 *
 * [ if a single-CPU system runs an SMP kernel then we call the local
 *   interrupt as well. Thus we cannot inline the local irq ... ]
 */
void smp_apic_timer_interrupt(struct pt_regs *regs)
{
	struct pt_regs *old_regs = set_irq_regs(regs);

	/*
	 * NOTE! We'd better ACK the irq immediately,
	 * because timer handling can be slow.
	 */
	ack_APIC_irq();
	/*
	 * update_process_times() expects us to have done irq_enter().
	 * Besides, if we don't timer interrupts ignore the global
	 * interrupt lock, which is the WrongThing (tm) to do.
	 */
	exit_idle();
	irq_enter();
	local_apic_timer_interrupt();
	irq_exit();
	set_irq_regs(old_regs);
}

int setup_profiling_timer(unsigned int multiplier)
{
	return -EINVAL;
}


/*
 * Local APIC start and shutdown
 */

/**
 * clear_local_APIC - shutdown the local APIC
 *
 * This is called, when a CPU is disabled and before rebooting, so the state of
 * the local APIC has no dangling leftovers. Also used to cleanout any BIOS
 * leftovers during boot.
 */
void clear_local_APIC(void)
{
	int maxlvt;
	u32 v;

	/* APIC hasn't been mapped yet */
	if (!apic_phys)
		return;

	maxlvt = lapic_get_maxlvt();
	/*
	 * Masking an LVT entry can trigger a local APIC error
	 * if the vector is zero. Mask LVTERR first to prevent this.
	 */
	if (maxlvt >= 3) {
		v = ERROR_APIC_VECTOR; /* any non-zero vector will do */
		apic_write(APIC_LVTERR, v | APIC_LVT_MASKED);
	}
	/*
	 * Careful: we have to set masks only first to deassert
	 * any level-triggered sources.
	 */
	v = apic_read(APIC_LVTT);
	apic_write(APIC_LVTT, v | APIC_LVT_MASKED);
	v = apic_read(APIC_LVT0);
	apic_write(APIC_LVT0, v | APIC_LVT_MASKED);
	v = apic_read(APIC_LVT1);
	apic_write(APIC_LVT1, v | APIC_LVT_MASKED);
	if (maxlvt >= 4) {
		v = apic_read(APIC_LVTPC);
		apic_write(APIC_LVTPC, v | APIC_LVT_MASKED);
	}

	/*
	 * Clean APIC state for other OSs:
	 */
	apic_write(APIC_LVTT, APIC_LVT_MASKED);
	apic_write(APIC_LVT0, APIC_LVT_MASKED);
	apic_write(APIC_LVT1, APIC_LVT_MASKED);
	if (maxlvt >= 3)
		apic_write(APIC_LVTERR, APIC_LVT_MASKED);
	if (maxlvt >= 4)
		apic_write(APIC_LVTPC, APIC_LVT_MASKED);
	apic_write(APIC_ESR, 0);
	apic_read(APIC_ESR);
}

/**
 * disable_local_APIC - clear and disable the local APIC
 */
void disable_local_APIC(void)
{
	unsigned int value;

	clear_local_APIC();

	/*
	 * Disable APIC (implies clearing of registers
	 * for 82489DX!).
	 */
	value = apic_read(APIC_SPIV);
	value &= ~APIC_SPIV_APIC_ENABLED;
	apic_write(APIC_SPIV, value);
}

void lapic_shutdown(void)
{
	unsigned long flags;

	if (!cpu_has_apic)
		return;

	local_irq_save(flags);

	disable_local_APIC();

	local_irq_restore(flags);
}

/*
 * This is to verify that we're looking at a real local APIC.
 * Check these against your board if the CPUs aren't getting
 * started for no apparent reason.
 */
int __init verify_local_APIC(void)
{
	unsigned int reg0, reg1;

	/*
	 * The version register is read-only in a real APIC.
	 */
	reg0 = apic_read(APIC_LVR);
	apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg0);
	apic_write(APIC_LVR, reg0 ^ APIC_LVR_MASK);
	reg1 = apic_read(APIC_LVR);
	apic_printk(APIC_DEBUG, "Getting VERSION: %x\n", reg1);

	/*
	 * The two version reads above should print the same
	 * numbers.  If the second one is different, then we
	 * poke at a non-APIC.
	 */
	if (reg1 != reg0)
		return 0;

	/*
	 * Check if the version looks reasonably.
	 */
	reg1 = GET_APIC_VERSION(reg0);
	if (reg1 == 0x00 || reg1 == 0xff)
		return 0;
	reg1 = lapic_get_maxlvt();
	if (reg1 < 0x02 || reg1 == 0xff)
		return 0;

	/*
	 * The ID register is read/write in a real APIC.
	 */
	reg0 = read_apic_id();
	apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg0);
	apic_write(APIC_ID, reg0 ^ APIC_ID_MASK);
	reg1 = read_apic_id();
	apic_printk(APIC_DEBUG, "Getting ID: %x\n", reg1);
	apic_write(APIC_ID, reg0);
	if (reg1 != (reg0 ^ APIC_ID_MASK))
		return 0;

	/*
	 * The next two are just to see if we have sane values.
	 * They're only really relevant if we're in Virtual Wire
	 * compatibility mode, but most boxes are anymore.
	 */
	reg0 = apic_read(APIC_LVT0);
	apic_printk(APIC_DEBUG, "Getting LVT0: %x\n", reg0);
	reg1 = apic_read(APIC_LVT1);
	apic_printk(APIC_DEBUG, "Getting LVT1: %x\n", reg1);

	return 1;
}

/**
 * sync_Arb_IDs - synchronize APIC bus arbitration IDs
 */
void __init sync_Arb_IDs(void)
{
	/* Unsupported on P4 - see Intel Dev. Manual Vol. 3, Ch. 8.6.1 */
	if (modern_apic())
		return;

	/*
	 * Wait for idle.
	 */
	apic_wait_icr_idle();

	apic_printk(APIC_DEBUG, "Synchronizing Arb IDs.\n");
	apic_write(APIC_ICR, APIC_DEST_ALLINC | APIC_INT_LEVELTRIG
				| APIC_DM_INIT);
}

/*
 * An initial setup of the virtual wire mode.
 */
void __init init_bsp_APIC(void)
{
	unsigned int value;

	/*
	 * Don't do the setup now if we have a SMP BIOS as the
	 * through-I/O-APIC virtual wire mode might be active.
	 */
	if (smp_found_config || !cpu_has_apic)
		return;

	value = apic_read(APIC_LVR);

	/*
	 * Do not trust the local APIC being empty at bootup.
	 */
	clear_local_APIC();

	/*
	 * Enable APIC.
	 */
	value = apic_read(APIC_SPIV);
	value &= ~APIC_VECTOR_MASK;
	value |= APIC_SPIV_APIC_ENABLED;
	value |= APIC_SPIV_FOCUS_DISABLED;
	value |= SPURIOUS_APIC_VECTOR;
	apic_write(APIC_SPIV, value);

	/*
	 * Set up the virtual wire mode.
	 */
	apic_write(APIC_LVT0, APIC_DM_EXTINT);
	value = APIC_DM_NMI;
	apic_write(APIC_LVT1, value);
}

/**
 * setup_local_APIC - setup the local APIC
 */
void __cpuinit setup_local_APIC(void)
{
	unsigned int value;
	int i, j;

	preempt_disable();
	value = apic_read(APIC_LVR);

	BUILD_BUG_ON((SPURIOUS_APIC_VECTOR & 0x0f) != 0x0f);

	/*
	 * Double-check whether this APIC is really registered.
	 * This is meaningless in clustered apic mode, so we skip it.
	 */
	if (!apic_id_registered())
		BUG();

	/*
	 * Intel recommends to set DFR, LDR and TPR before enabling
	 * an APIC.  See e.g. "AP-388 82489DX User's Manual" (Intel
	 * document number 292116).  So here it goes...
	 */
	init_apic_ldr();

	/*
	 * Set Task Priority to 'accept all'. We never change this
	 * later on.
	 */
	value = apic_read(APIC_TASKPRI);
	value &= ~APIC_TPRI_MASK;
	apic_write(APIC_TASKPRI, value);

	/*
	 * After a crash, we no longer service the interrupts and a pending
	 * interrupt from previous kernel might still have ISR bit set.
	 *
	 * Most probably by now CPU has serviced that pending interrupt and
	 * it might not have done the ack_APIC_irq() because it thought,
	 * interrupt came from i8259 as ExtInt. LAPIC did not get EOI so it
	 * does not clear the ISR bit and cpu thinks it has already serivced
	 * the interrupt. Hence a vector might get locked. It was noticed
	 * for timer irq (vector 0x31). Issue an extra EOI to clear ISR.
	 */
	for (i = APIC_ISR_NR - 1; i >= 0; i--) {
		value = apic_read(APIC_ISR + i*0x10);
		for (j = 31; j >= 0; j--) {
			if (value & (1<<j))
				ack_APIC_irq();
		}
	}

	/*
	 * Now that we are all set up, enable the APIC
	 */
	value = apic_read(APIC_SPIV);
	value &= ~APIC_VECTOR_MASK;
	/*
	 * Enable APIC
	 */
	value |= APIC_SPIV_APIC_ENABLED;

	/* We always use processor focus */

	/*
	 * Set spurious IRQ vector
	 */
	value |= SPURIOUS_APIC_VECTOR;
	apic_write(APIC_SPIV, value);

	/*
	 * Set up LVT0, LVT1:
	 *
	 * set up through-local-APIC on the BP's LINT0. This is not
	 * strictly necessary in pure symmetric-IO mode, but sometimes
	 * we delegate interrupts to the 8259A.
	 */
	/*
	 * TODO: set up through-local-APIC from through-I/O-APIC? --macro
	 */
	value = apic_read(APIC_LVT0) & APIC_LVT_MASKED;
	if (!smp_processor_id() && !value) {
		value = APIC_DM_EXTINT;
		apic_printk(APIC_VERBOSE, "enabled ExtINT on CPU#%d\n",
			    smp_processor_id());
	} else {
		value = APIC_DM_EXTINT | APIC_LVT_MASKED;
		apic_printk(APIC_VERBOSE, "masked ExtINT on CPU#%d\n",
			    smp_processor_id());
	}
	apic_write(APIC_LVT0, value);

	/*
	 * only the BP should see the LINT1 NMI signal, obviously.
	 */
	if (!smp_processor_id())
		value = APIC_DM_NMI;
	else
		value = APIC_DM_NMI | APIC_LVT_MASKED;
	apic_write(APIC_LVT1, value);
	preempt_enable();
}

static void __cpuinit lapic_setup_esr(void)
{
	unsigned maxlvt = lapic_get_maxlvt();

	apic_write(APIC_LVTERR, ERROR_APIC_VECTOR);
	/*
	 * spec says clear errors after enabling vector.
	 */
	if (maxlvt > 3)
		apic_write(APIC_ESR, 0);
}

void __cpuinit end_local_APIC_setup(void)
{
	lapic_setup_esr();
	setup_apic_nmi_watchdog(NULL);
	apic_pm_activate();
}

/*
 * Detect and enable local APICs on non-SMP boards.
 * Original code written by Keir Fraser.
 * On AMD64 we trust the BIOS - if it says no APIC it is likely
 * not correctly set up (usually the APIC timer won't work etc.)
 */
static int __init detect_init_APIC(void)
{
	if (!cpu_has_apic) {
		printk(KERN_INFO "No local APIC present\n");
		return -1;
	}

	mp_lapic_addr = APIC_DEFAULT_PHYS_BASE;
	boot_cpu_physical_apicid = 0;
	return 0;
}

void __init early_init_lapic_mapping(void)
{
	unsigned long phys_addr;

	/*
	 * If no local APIC can be found then go out
	 * : it means there is no mpatable and MADT
	 */
	if (!smp_found_config)
		return;

	phys_addr = mp_lapic_addr;

	set_fixmap_nocache(FIX_APIC_BASE, phys_addr);
	apic_printk(APIC_VERBOSE, "mapped APIC to %16lx (%16lx)\n",
		    APIC_BASE, phys_addr);

	/*
	 * Fetch the APIC ID of the BSP in case we have a
	 * default configuration (or the MP table is broken).
	 */
	boot_cpu_physical_apicid = GET_APIC_ID(read_apic_id());
}

/**
 * init_apic_mappings - initialize APIC mappings
 */
void __init init_apic_mappings(void)
{
	/*
	 * If no local APIC can be found then set up a fake all
	 * zeroes page to simulate the local APIC and another
	 * one for the IO-APIC.
	 */
	if (!smp_found_config && detect_init_APIC()) {
		apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
		apic_phys = __pa(apic_phys);
	} else
		apic_phys = mp_lapic_addr;

	set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
	apic_printk(APIC_VERBOSE, "mapped APIC to %16lx (%16lx)\n",
				APIC_BASE, apic_phys);

	/*
	 * Fetch the APIC ID of the BSP in case we have a
	 * default configuration (or the MP table is broken).
	 */
	boot_cpu_physical_apicid = GET_APIC_ID(read_apic_id());
}

/*
 * This initializes the IO-APIC and APIC hardware if this is
 * a UP kernel.
 */
int __init APIC_init_uniprocessor(void)
{
	if (disable_apic) {
		printk(KERN_INFO "Apic disabled\n");
		return -1;
	}
	if (!cpu_has_apic) {
		disable_apic = 1;
		printk(KERN_INFO "Apic disabled by BIOS\n");
		return -1;
	}

	verify_local_APIC();

	connect_bsp_APIC();

	physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
	apic_write(APIC_ID, SET_APIC_ID(boot_cpu_physical_apicid));

	setup_local_APIC();

	/*
	 * Now enable IO-APICs, actually call clear_IO_APIC
	 * We need clear_IO_APIC before enabling vector on BP
	 */
	if (!skip_ioapic_setup && nr_ioapics)
		enable_IO_APIC();

	if (!smp_found_config || skip_ioapic_setup || !nr_ioapics)
		localise_nmi_watchdog();
	end_local_APIC_setup();

	if (smp_found_config && !skip_ioapic_setup && nr_ioapics)
		setup_IO_APIC();
	else
		nr_ioapics = 0;
	setup_boot_APIC_clock();
	check_nmi_watchdog();
	return 0;
}

/*
 * Local APIC interrupts
 */

/*
 * This interrupt should _never_ happen with our APIC/SMP architecture
 */
asmlinkage void smp_spurious_interrupt(void)
{
	unsigned int v;
	exit_idle();
	irq_enter();
	/*
	 * Check if this really is a spurious interrupt and ACK it
	 * if it is a vectored one.  Just in case...
	 * Spurious interrupts should not be ACKed.
	 */
	v = apic_read(APIC_ISR + ((SPURIOUS_APIC_VECTOR & ~0x1f) >> 1));
	if (v & (1 << (SPURIOUS_APIC_VECTOR & 0x1f)))
		ack_APIC_irq();

	add_pda(irq_spurious_count, 1);
	irq_exit();
}

/*
 * This interrupt should never happen with our APIC/SMP architecture
 */
asmlinkage void smp_error_interrupt(void)
{
	unsigned int v, v1;

	exit_idle();
	irq_enter();
	/* First tickle the hardware, only then report what went on. -- REW */
	v = apic_read(APIC_ESR);
	apic_write(APIC_ESR, 0);
	v1 = apic_read(APIC_ESR);
	ack_APIC_irq();
	atomic_inc(&irq_err_count);

	/* Here is what the APIC error bits mean:
	   0: Send CS error
	   1: Receive CS error
	   2: Send accept error
	   3: Receive accept error
	   4: Reserved
	   5: Send illegal vector
	   6: Received illegal vector
	   7: Illegal register address
	*/
	printk(KERN_DEBUG "APIC error on CPU%d: %02x(%02x)\n",
		smp_processor_id(), v , v1);
	irq_exit();
}

/**
 *  * connect_bsp_APIC - attach the APIC to the interrupt system
 *   */
void __init connect_bsp_APIC(void)
{
	enable_apic_mode();
}

void disconnect_bsp_APIC(int virt_wire_setup)
{
	/* Go back to Virtual Wire compatibility mode */
	unsigned long value;

	/* For the spurious interrupt use vector F, and enable it */
	value = apic_read(APIC_SPIV);
	value &= ~APIC_VECTOR_MASK;
	value |= APIC_SPIV_APIC_ENABLED;
	value |= 0xf;
	apic_write(APIC_SPIV, value);

	if (!virt_wire_setup) {
		/*
		 * For LVT0 make it edge triggered, active high,
		 * external and enabled
		 */
		value = apic_read(APIC_LVT0);
		value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
			APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
			APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
		value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
		value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_EXTINT);
		apic_write(APIC_LVT0, value);
	} else {
		/* Disable LVT0 */
		apic_write(APIC_LVT0, APIC_LVT_MASKED);
	}

	/* For LVT1 make it edge triggered, active high, nmi and enabled */
	value = apic_read(APIC_LVT1);
	value &= ~(APIC_MODE_MASK | APIC_SEND_PENDING |
			APIC_INPUT_POLARITY | APIC_LVT_REMOTE_IRR |
			APIC_LVT_LEVEL_TRIGGER | APIC_LVT_MASKED);
	value |= APIC_LVT_REMOTE_IRR | APIC_SEND_PENDING;
	value = SET_APIC_DELIVERY_MODE(value, APIC_MODE_NMI);
	apic_write(APIC_LVT1, value);
}

void __cpuinit generic_processor_info(int apicid, int version)
{
	int cpu;
	cpumask_t tmp_map;

	if (num_processors >= NR_CPUS) {
		printk(KERN_WARNING "WARNING: NR_CPUS limit of %i reached."
		       " Processor ignored.\n", NR_CPUS);
		return;
	}

	if (num_processors >= maxcpus) {
		printk(KERN_WARNING "WARNING: maxcpus limit of %i reached."
		       " Processor ignored.\n", maxcpus);
		return;
	}

	num_processors++;
	cpus_complement(tmp_map, cpu_present_map);
	cpu = first_cpu(tmp_map);

	physid_set(apicid, phys_cpu_present_map);
	if (apicid == boot_cpu_physical_apicid) {
		/*
		 * x86_bios_cpu_apicid is required to have processors listed
		 * in same order as logical cpu numbers. Hence the first
		 * entry is BSP, and so on.
		 */
		cpu = 0;
	}
	if (apicid > max_physical_apicid)
		max_physical_apicid = apicid;

	/* are we being called early in kernel startup? */
	if (early_per_cpu_ptr(x86_cpu_to_apicid)) {
		u16 *cpu_to_apicid = early_per_cpu_ptr(x86_cpu_to_apicid);
		u16 *bios_cpu_apicid = early_per_cpu_ptr(x86_bios_cpu_apicid);

		cpu_to_apicid[cpu] = apicid;
		bios_cpu_apicid[cpu] = apicid;
	} else {
		per_cpu(x86_cpu_to_apicid, cpu) = apicid;
		per_cpu(x86_bios_cpu_apicid, cpu) = apicid;
	}

	cpu_set(cpu, cpu_possible_map);
	cpu_set(cpu, cpu_present_map);
}

/*
 * Power management
 */
#ifdef CONFIG_PM

static struct {
	/* 'active' is true if the local APIC was enabled by us and
	   not the BIOS; this signifies that we are also responsible
	   for disabling it before entering apm/acpi suspend */
	int active;
	/* r/w apic fields */
	unsigned int apic_id;
	unsigned int apic_taskpri;
	unsigned int apic_ldr;
	unsigned int apic_dfr;
	unsigned int apic_spiv;
	unsigned int apic_lvtt;
	unsigned int apic_lvtpc;
	unsigned int apic_lvt0;
	unsigned int apic_lvt1;
	unsigned int apic_lvterr;
	unsigned int apic_tmict;
	unsigned int apic_tdcr;
	unsigned int apic_thmr;
} apic_pm_state;

static int lapic_suspend(struct sys_device *dev, pm_message_t state)
{
	unsigned long flags;
	int maxlvt;

	if (!apic_pm_state.active)
		return 0;

	maxlvt = lapic_get_maxlvt();

	apic_pm_state.apic_id = read_apic_id();
	apic_pm_state.apic_taskpri = apic_read(APIC_TASKPRI);
	apic_pm_state.apic_ldr = apic_read(APIC_LDR);
	apic_pm_state.apic_dfr = apic_read(APIC_DFR);
	apic_pm_state.apic_spiv = apic_read(APIC_SPIV);
	apic_pm_state.apic_lvtt = apic_read(APIC_LVTT);
	if (maxlvt >= 4)
		apic_pm_state.apic_lvtpc = apic_read(APIC_LVTPC);
	apic_pm_state.apic_lvt0 = apic_read(APIC_LVT0);
	apic_pm_state.apic_lvt1 = apic_read(APIC_LVT1);
	apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
	apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
	apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
#ifdef CONFIG_X86_MCE_INTEL
	if (maxlvt >= 5)
		apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
#endif
	local_irq_save(flags);
	disable_local_APIC();
	local_irq_restore(flags);
	return 0;
}

static int lapic_resume(struct sys_device *dev)
{
	unsigned int l, h;
	unsigned long flags;
	int maxlvt;

	if (!apic_pm_state.active)
		return 0;

	maxlvt = lapic_get_maxlvt();

	local_irq_save(flags);
	rdmsr(MSR_IA32_APICBASE, l, h);
	l &= ~MSR_IA32_APICBASE_BASE;
	l |= MSR_IA32_APICBASE_ENABLE | mp_lapic_addr;
	wrmsr(MSR_IA32_APICBASE, l, h);
	apic_write(APIC_LVTERR, ERROR_APIC_VECTOR | APIC_LVT_MASKED);
	apic_write(APIC_ID, apic_pm_state.apic_id);
	apic_write(APIC_DFR, apic_pm_state.apic_dfr);
	apic_write(APIC_LDR, apic_pm_state.apic_ldr);
	apic_write(APIC_TASKPRI, apic_pm_state.apic_taskpri);
	apic_write(APIC_SPIV, apic_pm_state.apic_spiv);
	apic_write(APIC_LVT0, apic_pm_state.apic_lvt0);
	apic_write(APIC_LVT1, apic_pm_state.apic_lvt1);
#ifdef CONFIG_X86_MCE_INTEL
	if (maxlvt >= 5)
		apic_write(APIC_LVTTHMR, apic_pm_state.apic_thmr);
#endif
	if (maxlvt >= 4)
		apic_write(APIC_LVTPC, apic_pm_state.apic_lvtpc);
	apic_write(APIC_LVTT, apic_pm_state.apic_lvtt);
	apic_write(APIC_TDCR, apic_pm_state.apic_tdcr);
	apic_write(APIC_TMICT, apic_pm_state.apic_tmict);
	apic_write(APIC_ESR, 0);
	apic_read(APIC_ESR);
	apic_write(APIC_LVTERR, apic_pm_state.apic_lvterr);
	apic_write(APIC_ESR, 0);
	apic_read(APIC_ESR);
	local_irq_restore(flags);
	return 0;
}

static struct sysdev_class lapic_sysclass = {
	.name		= "lapic",
	.resume		= lapic_resume,
	.suspend	= lapic_suspend,
};

static struct sys_device device_lapic = {
	.id	= 0,
	.cls	= &lapic_sysclass,
};

static void __cpuinit apic_pm_activate(void)
{
	apic_pm_state.active = 1;
}

static int __init init_lapic_sysfs(void)
{
	int error;

	if (!cpu_has_apic)
		return 0;
	/* XXX: remove suspend/resume procs if !apic_pm_state.active? */

	error = sysdev_class_register(&lapic_sysclass);
	if (!error)
		error = sysdev_register(&device_lapic);
	return error;
}
device_initcall(init_lapic_sysfs);

#else	/* CONFIG_PM */

static void apic_pm_activate(void) { }

#endif	/* CONFIG_PM */

/*
 * apic_is_clustered_box() -- Check if we can expect good TSC
 *
 * Thus far, the major user of this is IBM's Summit2 series:
 *
 * Clustered boxes may have unsynced TSC problems if they are
 * multi-chassis. Use available data to take a good guess.
 * If in doubt, go HPET.
 */
__cpuinit int apic_is_clustered_box(void)
{
	int i, clusters, zeros;
	unsigned id;
	u16 *bios_cpu_apicid;
	DECLARE_BITMAP(clustermap, NUM_APIC_CLUSTERS);

	/*
	 * there is not this kind of box with AMD CPU yet.
	 * Some AMD box with quadcore cpu and 8 sockets apicid
	 * will be [4, 0x23] or [8, 0x27] could be thought to
	 * vsmp box still need checking...
	 */
	if ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && !is_vsmp_box())
		return 0;

	bios_cpu_apicid = early_per_cpu_ptr(x86_bios_cpu_apicid);
	bitmap_zero(clustermap, NUM_APIC_CLUSTERS);

	for (i = 0; i < NR_CPUS; i++) {
		/* are we being called early in kernel startup? */
		if (bios_cpu_apicid) {
			id = bios_cpu_apicid[i];
		}
		else if (i < nr_cpu_ids) {
			if (cpu_present(i))
				id = per_cpu(x86_bios_cpu_apicid, i);
			else
				continue;
		}
		else
			break;

		if (id != BAD_APICID)
			__set_bit(APIC_CLUSTERID(id), clustermap);
	}

	/* Problem:  Partially populated chassis may not have CPUs in some of
	 * the APIC clusters they have been allocated.  Only present CPUs have
	 * x86_bios_cpu_apicid entries, thus causing zeroes in the bitmap.
	 * Since clusters are allocated sequentially, count zeros only if
	 * they are bounded by ones.
	 */
	clusters = 0;
	zeros = 0;
	for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
		if (test_bit(i, clustermap)) {
			clusters += 1 + zeros;
			zeros = 0;
		} else
			++zeros;
	}

	/* ScaleMP vSMPowered boxes have one cluster per board and TSCs are
	 * not guaranteed to be synced between boards
	 */
	if (is_vsmp_box() && clusters > 1)
		return 1;

	/*
	 * If clusters > 2, then should be multi-chassis.
	 * May have to revisit this when multi-core + hyperthreaded CPUs come
	 * out, but AFAIK this will work even for them.
	 */
	return (clusters > 2);
}

/*
 * APIC command line parameters
 */
static int __init apic_set_verbosity(char *str)
{
	if (str == NULL)  {
		skip_ioapic_setup = 0;
		ioapic_force = 1;
		return 0;
	}
	if (strcmp("debug", str) == 0)
		apic_verbosity = APIC_DEBUG;
	else if (strcmp("verbose", str) == 0)
		apic_verbosity = APIC_VERBOSE;
	else {
		printk(KERN_WARNING "APIC Verbosity level %s not recognised"
				" use apic=verbose or apic=debug\n", str);
		return -EINVAL;
	}

	return 0;
}
early_param("apic", apic_set_verbosity);

static __init int setup_disableapic(char *str)
{
	disable_apic = 1;
	setup_clear_cpu_cap(X86_FEATURE_APIC);
	return 0;
}
early_param("disableapic", setup_disableapic);

/* same as disableapic, for compatibility */
static __init int setup_nolapic(char *str)
{
	return setup_disableapic(str);
}
early_param("nolapic", setup_nolapic);

static int __init parse_lapic_timer_c2_ok(char *arg)
{
	local_apic_timer_c2_ok = 1;
	return 0;
}
early_param("lapic_timer_c2_ok", parse_lapic_timer_c2_ok);

static __init int setup_noapictimer(char *str)
{
	if (str[0] != ' ' && str[0] != 0)
		return 0;
	disable_apic_timer = 1;
	return 1;
}
__setup("noapictimer", setup_noapictimer);

static __init int setup_apicpmtimer(char *s)
{
	apic_calibrate_pmtmr = 1;
	notsc_setup(NULL);
	return 0;
}
__setup("apicpmtimer", setup_apicpmtimer);

static int __init lapic_insert_resource(void)
{
	if (!apic_phys)
		return -1;

	/* Put local APIC into the resource map. */
	lapic_resource.start = apic_phys;
	lapic_resource.end = lapic_resource.start + PAGE_SIZE - 1;
	insert_resource(&iomem_resource, &lapic_resource);

	return 0;
}

/*
 * need call insert after e820_reserve_resources()
 * that is using request_resource
 */
late_initcall(lapic_insert_resource);