xref: /dflybsd-src/sys/platform/pc64/apic/lapic.c (revision 0c1d7dca433e727c476aff53acb839b357a28ef6)
1 /*
2  * Copyright (c) 1996, by Steve Passe
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. The name of the developer may NOT be used to endorse or promote products
11  *    derived from this software without specific prior written permission.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23  * SUCH DAMAGE.
24  *
25  * $FreeBSD: src/sys/i386/i386/mpapic.c,v 1.37.2.7 2003/01/25 02:31:47 peter Exp $
26  */
27 
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/kernel.h>
31 #include <sys/bus.h>
32 #include <sys/machintr.h>
33 #include <machine/globaldata.h>
34 #include <machine/smp.h>
35 #include <machine/md_var.h>
36 #include <machine/pmap.h>
37 #include <machine/specialreg.h>
38 #include <machine_base/apic/lapic.h>
39 #include <machine_base/apic/ioapic.h>
40 #include <machine_base/apic/ioapic_abi.h>
41 #include <machine_base/apic/apicvar.h>
42 #include <machine_base/icu/icu_var.h>
43 #include <machine/segments.h>
44 #include <sys/thread2.h>
45 
46 #include <machine/cputypes.h>
47 #include <machine/intr_machdep.h>
48 
49 extern int naps;
50 
51 volatile lapic_t *lapic;
52 
53 static void	lapic_timer_calibrate(void);
54 static void	lapic_timer_set_divisor(int);
55 static void	lapic_timer_fixup_handler(void *);
56 static void	lapic_timer_restart_handler(void *);
57 
58 
59 static int	lapic_timer_enable = 1;
60 TUNABLE_INT("hw.lapic_timer_enable", &lapic_timer_enable);
61 
62 static void	lapic_timer_intr_reload(struct cputimer_intr *, sysclock_t);
63 static void	lapic_timer_intr_enable(struct cputimer_intr *);
64 static void	lapic_timer_intr_restart(struct cputimer_intr *);
65 static void	lapic_timer_intr_pmfixup(struct cputimer_intr *);
66 
67 static struct cputimer_intr lapic_cputimer_intr = {
68 	.freq = 0,
69 	.reload = lapic_timer_intr_reload,
70 	.enable = lapic_timer_intr_enable,
71 	.config = cputimer_intr_default_config,
72 	.restart = lapic_timer_intr_restart,
73 	.pmfixup = lapic_timer_intr_pmfixup,
74 	.initclock = cputimer_intr_default_initclock,
75 	.pcpuhand = NULL,
76 	.next = SLIST_ENTRY_INITIALIZER,
77 	.name = "lapic",
78 	.type = CPUTIMER_INTR_LAPIC,
79 	.prio = CPUTIMER_INTR_PRIO_LAPIC,
80 	.caps = CPUTIMER_INTR_CAP_NONE,
81 	.priv = NULL
82 };
83 
84 static int		lapic_timer_divisor_idx = -1;
85 static const uint32_t	lapic_timer_divisors[] = {
86 	APIC_TDCR_2,	APIC_TDCR_4,	APIC_TDCR_8,	APIC_TDCR_16,
87 	APIC_TDCR_32,	APIC_TDCR_64,	APIC_TDCR_128,	APIC_TDCR_1
88 };
89 #define APIC_TIMER_NDIVISORS (int)(NELEM(lapic_timer_divisors))
90 
91 /*
92  * APIC ID <-> CPU ID mapping structures.
93  */
94 int	cpu_id_to_apic_id[NAPICID];
95 int	apic_id_to_cpu_id[NAPICID];
96 int	lapic_enable = 1;
97 
98 /*
99  * Enable LAPIC, configure interrupts.
100  */
101 void
102 lapic_init(boolean_t bsp)
103 {
104 	uint32_t timer;
105 	u_int   temp;
106 
107 	/*
108 	 * Install vectors
109 	 *
110 	 * Since IDT is shared between BSP and APs, these vectors
111 	 * only need to be installed once; we do it on BSP.
112 	 */
113 	if (bsp) {
114 		if (cpu_vendor_id == CPU_VENDOR_AMD &&
115 		    CPUID_TO_FAMILY(cpu_id) >= 0xf) {
116 			uint32_t tcr;
117 
118 			/*
119 			 * Set the LINTEN bit in the HyperTransport
120 			 * Transaction Control Register.
121 			 *
122 			 * This will cause EXTINT and NMI interrupts
123 			 * routed over the hypertransport bus to be
124 			 * fed into the LAPIC LINT0/LINT1.  If the bit
125 			 * isn't set, the interrupts will go to the
126 			 * general cpu INTR/NMI pins.  On a dual-core
127 			 * cpu the interrupt winds up going to BOTH cpus.
128 			 * The first cpu that does the interrupt ack
129 			 * cycle will get the correct interrupt.  The
130 			 * second cpu that does it will get a spurious
131 			 * interrupt vector (typically IRQ 7).
132 			 */
133 			outl(0x0cf8,
134 			    (1 << 31) |	/* enable */
135 			    (0 << 16) |	/* bus */
136 			    (0x18 << 11) | /* dev (cpu + 0x18) */
137 			    (0 << 8) |	/* func */
138 			    0x68	/* reg */
139 			    );
140 			tcr = inl(0xcfc);
141 			if ((tcr & 0x00010000) == 0) {
142 				kprintf("LAPIC: AMD LINTEN on\n");
143 				outl(0xcfc, tcr|0x00010000);
144 			}
145 			outl(0x0cf8, 0);
146 		}
147 
148 		/* Install a 'Spurious INTerrupt' vector */
149 		setidt_global(XSPURIOUSINT_OFFSET, Xspuriousint,
150 		    SDT_SYSIGT, SEL_KPL, 0);
151 
152 		/* Install a timer vector */
153 		setidt_global(XTIMER_OFFSET, Xtimer,
154 		    SDT_SYSIGT, SEL_KPL, 0);
155 
156 		/* Install an inter-CPU IPI for TLB invalidation */
157 		setidt_global(XINVLTLB_OFFSET, Xinvltlb,
158 		    SDT_SYSIGT, SEL_KPL, 0);
159 
160 		/* Install an inter-CPU IPI for IPIQ messaging */
161 		setidt_global(XIPIQ_OFFSET, Xipiq,
162 		    SDT_SYSIGT, SEL_KPL, 0);
163 
164 		/* Install an inter-CPU IPI for CPU stop/restart */
165 		setidt_global(XCPUSTOP_OFFSET, Xcpustop,
166 		    SDT_SYSIGT, SEL_KPL, 0);
167 	}
168 
169 	/*
170 	 * Setup LINT0 as ExtINT on the BSP.  This is theoretically an
171 	 * aggregate interrupt input from the 8259.  The INTA cycle
172 	 * will be routed to the external controller (the 8259) which
173 	 * is expected to supply the vector.
174 	 *
175 	 * Must be setup edge triggered, active high.
176 	 *
177 	 * Disable LINT0 on BSP, if I/O APIC is enabled.
178 	 *
179 	 * Disable LINT0 on the APs.  It doesn't matter what delivery
180 	 * mode we use because we leave it masked.
181 	 */
182 	temp = lapic->lvt_lint0;
183 	temp &= ~(APIC_LVT_MASKED | APIC_LVT_TRIG_MASK |
184 		  APIC_LVT_POLARITY_MASK | APIC_LVT_DM_MASK);
185 	if (bsp) {
186 		temp |= APIC_LVT_DM_EXTINT;
187 		if (ioapic_enable)
188 			temp |= APIC_LVT_MASKED;
189 	} else {
190 		temp |= APIC_LVT_DM_FIXED | APIC_LVT_MASKED;
191 	}
192 	lapic->lvt_lint0 = temp;
193 
194 	/*
195 	 * Setup LINT1 as NMI.
196 	 *
197 	 * Must be setup edge trigger, active high.
198 	 *
199 	 * Enable LINT1 on BSP, if I/O APIC is enabled.
200 	 *
201 	 * Disable LINT1 on the APs.
202 	 */
203 	temp = lapic->lvt_lint1;
204 	temp &= ~(APIC_LVT_MASKED | APIC_LVT_TRIG_MASK |
205 		  APIC_LVT_POLARITY_MASK | APIC_LVT_DM_MASK);
206 	temp |= APIC_LVT_MASKED | APIC_LVT_DM_NMI;
207 	if (bsp && ioapic_enable)
208 		temp &= ~APIC_LVT_MASKED;
209 	lapic->lvt_lint1 = temp;
210 
211 	/*
212 	 * Mask the LAPIC error interrupt, LAPIC performance counter
213 	 * interrupt.
214 	 */
215 	lapic->lvt_error = lapic->lvt_error | APIC_LVT_MASKED;
216 	lapic->lvt_pcint = lapic->lvt_pcint | APIC_LVT_MASKED;
217 
218 	/*
219 	 * Set LAPIC timer vector and mask the LAPIC timer interrupt.
220 	 */
221 	timer = lapic->lvt_timer;
222 	timer &= ~APIC_LVTT_VECTOR;
223 	timer |= XTIMER_OFFSET;
224 	timer |= APIC_LVTT_MASKED;
225 	lapic->lvt_timer = timer;
226 
227 	/*
228 	 * Set the Task Priority Register as needed.   At the moment allow
229 	 * interrupts on all cpus (the APs will remain CLId until they are
230 	 * ready to deal).
231 	 */
232 	temp = lapic->tpr;
233 	temp &= ~APIC_TPR_PRIO;		/* clear priority field */
234 	lapic->tpr = temp;
235 
236 	/*
237 	 * Enable the LAPIC
238 	 */
239 	temp = lapic->svr;
240 	temp |= APIC_SVR_ENABLE;	/* enable the LAPIC */
241 	temp &= ~APIC_SVR_FOCUS_DISABLE; /* enable lopri focus processor */
242 
243 	/*
244 	 * Set the spurious interrupt vector.  The low 4 bits of the vector
245 	 * must be 1111.
246 	 */
247 	if ((XSPURIOUSINT_OFFSET & 0x0F) != 0x0F)
248 		panic("bad XSPURIOUSINT_OFFSET: 0x%08x", XSPURIOUSINT_OFFSET);
249 	temp &= ~APIC_SVR_VECTOR;
250 	temp |= XSPURIOUSINT_OFFSET;
251 
252 	lapic->svr = temp;
253 
254 	/*
255 	 * Pump out a few EOIs to clean out interrupts that got through
256 	 * before we were able to set the TPR.
257 	 */
258 	lapic->eoi = 0;
259 	lapic->eoi = 0;
260 	lapic->eoi = 0;
261 
262 	if (bsp) {
263 		lapic_timer_calibrate();
264 		if (lapic_timer_enable) {
265 			if (cpu_thermal_feature & CPUID_THERMAL_ARAT) {
266 				/*
267 				 * Local APIC timer will not stop
268 				 * in deep C-state.
269 				 */
270 				lapic_cputimer_intr.caps |=
271 				    CPUTIMER_INTR_CAP_PS;
272 			}
273 			cputimer_intr_register(&lapic_cputimer_intr);
274 			cputimer_intr_select(&lapic_cputimer_intr, 0);
275 		}
276 	} else {
277 		lapic_timer_set_divisor(lapic_timer_divisor_idx);
278 	}
279 
280 	if (bootverbose)
281 		apic_dump("apic_initialize()");
282 }
283 
284 static void
285 lapic_timer_set_divisor(int divisor_idx)
286 {
287 	KKASSERT(divisor_idx >= 0 && divisor_idx < APIC_TIMER_NDIVISORS);
288 	lapic->dcr_timer = lapic_timer_divisors[divisor_idx];
289 }
290 
291 static void
292 lapic_timer_oneshot(u_int count)
293 {
294 	uint32_t value;
295 
296 	value = lapic->lvt_timer;
297 	value &= ~APIC_LVTT_PERIODIC;
298 	lapic->lvt_timer = value;
299 	lapic->icr_timer = count;
300 }
301 
302 static void
303 lapic_timer_oneshot_quick(u_int count)
304 {
305 	lapic->icr_timer = count;
306 }
307 
308 static void
309 lapic_timer_calibrate(void)
310 {
311 	sysclock_t value;
312 
313 	/* Try to calibrate the local APIC timer. */
314 	for (lapic_timer_divisor_idx = 0;
315 	     lapic_timer_divisor_idx < APIC_TIMER_NDIVISORS;
316 	     lapic_timer_divisor_idx++) {
317 		lapic_timer_set_divisor(lapic_timer_divisor_idx);
318 		lapic_timer_oneshot(APIC_TIMER_MAX_COUNT);
319 		DELAY(2000000);
320 		value = APIC_TIMER_MAX_COUNT - lapic->ccr_timer;
321 		if (value != APIC_TIMER_MAX_COUNT)
322 			break;
323 	}
324 	if (lapic_timer_divisor_idx >= APIC_TIMER_NDIVISORS)
325 		panic("lapic: no proper timer divisor?!");
326 	lapic_cputimer_intr.freq = value / 2;
327 
328 	kprintf("lapic: divisor index %d, frequency %u Hz\n",
329 		lapic_timer_divisor_idx, lapic_cputimer_intr.freq);
330 }
331 
332 static void
333 lapic_timer_intr_reload(struct cputimer_intr *cti, sysclock_t reload)
334 {
335 	struct globaldata *gd = mycpu;
336 
337 	reload = (int64_t)reload * cti->freq / sys_cputimer->freq;
338 	if (reload < 2)
339 		reload = 2;
340 
341 	if (gd->gd_timer_running) {
342 		if (reload < lapic->ccr_timer)
343 			lapic_timer_oneshot_quick(reload);
344 	} else {
345 		gd->gd_timer_running = 1;
346 		lapic_timer_oneshot_quick(reload);
347 	}
348 }
349 
350 static void
351 lapic_timer_intr_enable(struct cputimer_intr *cti __unused)
352 {
353 	uint32_t timer;
354 
355 	timer = lapic->lvt_timer;
356 	timer &= ~(APIC_LVTT_MASKED | APIC_LVTT_PERIODIC);
357 	lapic->lvt_timer = timer;
358 
359 	lapic_timer_fixup_handler(NULL);
360 }
361 
362 static void
363 lapic_timer_fixup_handler(void *arg)
364 {
365 	int *started = arg;
366 
367 	if (started != NULL)
368 		*started = 0;
369 
370 	if (cpu_vendor_id == CPU_VENDOR_AMD) {
371 		/*
372 		 * Detect the presence of C1E capability mostly on latest
373 		 * dual-cores (or future) k8 family.  This feature renders
374 		 * the local APIC timer dead, so we disable it by reading
375 		 * the Interrupt Pending Message register and clearing both
376 		 * C1eOnCmpHalt (bit 28) and SmiOnCmpHalt (bit 27).
377 		 *
378 		 * Reference:
379 		 *   "BIOS and Kernel Developer's Guide for AMD NPT
380 		 *    Family 0Fh Processors"
381 		 *   #32559 revision 3.00
382 		 */
383 		if ((cpu_id & 0x00000f00) == 0x00000f00 &&
384 		    (cpu_id & 0x0fff0000) >= 0x00040000) {
385 			uint64_t msr;
386 
387 			msr = rdmsr(0xc0010055);
388 			if (msr & 0x18000000) {
389 				struct globaldata *gd = mycpu;
390 
391 				kprintf("cpu%d: AMD C1E detected\n",
392 					gd->gd_cpuid);
393 				wrmsr(0xc0010055, msr & ~0x18000000ULL);
394 
395 				/*
396 				 * We are kinda stalled;
397 				 * kick start again.
398 				 */
399 				gd->gd_timer_running = 1;
400 				lapic_timer_oneshot_quick(2);
401 
402 				if (started != NULL)
403 					*started = 1;
404 			}
405 		}
406 	}
407 }
408 
409 static void
410 lapic_timer_restart_handler(void *dummy __unused)
411 {
412 	int started;
413 
414 	lapic_timer_fixup_handler(&started);
415 	if (!started) {
416 		struct globaldata *gd = mycpu;
417 
418 		gd->gd_timer_running = 1;
419 		lapic_timer_oneshot_quick(2);
420 	}
421 }
422 
423 /*
424  * This function is called only by ACPICA code currently:
425  * - AMD C1E fixup.  AMD C1E only seems to happen after ACPI
426  *   module controls PM.  So once ACPICA is attached, we try
427  *   to apply the fixup to prevent LAPIC timer from hanging.
428  */
429 static void
430 lapic_timer_intr_pmfixup(struct cputimer_intr *cti __unused)
431 {
432 	lwkt_send_ipiq_mask(smp_active_mask,
433 			    lapic_timer_fixup_handler, NULL);
434 }
435 
436 static void
437 lapic_timer_intr_restart(struct cputimer_intr *cti __unused)
438 {
439 	lwkt_send_ipiq_mask(smp_active_mask, lapic_timer_restart_handler, NULL);
440 }
441 
442 
443 /*
444  * dump contents of local APIC registers
445  */
446 void
447 apic_dump(char* str)
448 {
449 	kprintf("SMP: CPU%d %s:\n", mycpu->gd_cpuid, str);
450 	kprintf("     lint0: 0x%08x lint1: 0x%08x TPR: 0x%08x SVR: 0x%08x\n",
451 		lapic->lvt_lint0, lapic->lvt_lint1, lapic->tpr, lapic->svr);
452 }
453 
454 /*
455  * Inter Processor Interrupt functions.
456  */
457 
458 /*
459  * Send APIC IPI 'vector' to 'destType' via 'deliveryMode'.
460  *
461  *  destType is 1 of: APIC_DEST_SELF, APIC_DEST_ALLISELF, APIC_DEST_ALLESELF
462  *  vector is any valid SYSTEM INT vector
463  *  delivery_mode is 1 of: APIC_DELMODE_FIXED, APIC_DELMODE_LOWPRIO
464  *
465  * WARNINGS!
466  *
467  * We now implement a per-cpu interlock (gd->gd_npoll) to prevent more than
468  * one IPI from being sent to any given cpu at a time.  Thus we no longer
469  * have to process incoming IPIs while waiting for the status to clear.
470  * No deadlock should be possible.
471  *
472  * We now physically disable interrupts for the lapic ICR operation.  If
473  * we do not do this then it looks like an EOI sent to the lapic (which
474  * occurs even with a critical section) can interfere with the command
475  * register ready status and cause an IPI to be lost.
476  *
477  * e.g. an interrupt can occur, issue the EOI, IRET, and cause the command
478  * register to busy just before we write to icr_lo, resulting in a lost
479  * issuance.  This only appears to occur on Intel cpus and is not
480  * documented.  It could simply be that cpus are so fast these days that
481  * it was always an issue, but is only now rearing its ugly head.  This
482  * is conjecture.
483  */
484 int
485 apic_ipi(int dest_type, int vector, int delivery_mode)
486 {
487 	unsigned long rflags;
488 	u_long  icr_lo;
489 	int loops = 1;
490 
491 	rflags = read_rflags();
492 	cpu_disable_intr();
493 	while ((lapic->icr_lo & APIC_DELSTAT_MASK) != 0) {
494 		cpu_pause();
495 		if (++loops == 10000000)
496 			kprintf("apic_ipi stall cpu %d\n", mycpuid);
497 	}
498 	icr_lo = (lapic->icr_lo & APIC_ICRLO_RESV_MASK) | dest_type |
499 		delivery_mode | vector;
500 	lapic->icr_lo = icr_lo;
501 	write_rflags(rflags);
502 
503 	return 0;
504 }
505 
506 void
507 single_apic_ipi(int cpu, int vector, int delivery_mode)
508 {
509 	unsigned long rflags;
510 	u_long  icr_lo;
511 	u_long  icr_hi;
512 	int loops = 1;
513 
514 	rflags = read_rflags();
515 	cpu_disable_intr();
516 	while ((lapic->icr_lo & APIC_DELSTAT_MASK) != 0) {
517 		cpu_pause();
518 		if (++loops == 10000000)
519 			kprintf("apic_ipi stall cpu %d (sing)\n", mycpuid);
520 	}
521 	icr_hi = lapic->icr_hi & ~APIC_ID_MASK;
522 	icr_hi |= (CPUID_TO_APICID(cpu) << 24);
523 	lapic->icr_hi = icr_hi;
524 
525 	/* build ICR_LOW */
526 	icr_lo = (lapic->icr_lo & APIC_ICRLO_RESV_MASK) |
527 		 APIC_DEST_DESTFLD | delivery_mode | vector;
528 
529 	/* write APIC ICR */
530 	lapic->icr_lo = icr_lo;
531 	write_rflags(rflags);
532 }
533 
534 #if 0
535 
536 /*
537  * Returns 0 if the apic is busy, 1 if we were able to queue the request.
538  *
539  * NOT WORKING YET!  The code as-is may end up not queueing an IPI at all
540  * to the target, and the scheduler does not 'poll' for IPI messages.
541  */
542 int
543 single_apic_ipi_passive(int cpu, int vector, int delivery_mode)
544 {
545 	u_long  icr_lo;
546 	u_long  icr_hi;
547 	unsigned long rflags;
548 
549 	rflags = read_rflags();
550 	cpu_disable_intr();
551 	if ((lapic->icr_lo & APIC_DELSTAT_MASK) != 0) {
552 		write_rflags(rflags);
553 		return(0);
554 	}
555 	icr_hi = lapic->icr_hi & ~APIC_ID_MASK;
556 	icr_hi |= (CPUID_TO_APICID(cpu) << 24);
557 	lapic->icr_hi = icr_hi;
558 
559 	/* build IRC_LOW */
560 	icr_lo = (lapic->icr_lo & APIC_RESV2_MASK) |
561 		 APIC_DEST_DESTFLD | delivery_mode | vector;
562 
563 	/* write APIC ICR */
564 	lapic->icr_lo = icr_lo;
565 	write_rflags(rflags);
566 
567 	return(1);
568 }
569 
570 #endif
571 
572 /*
573  * Send APIC IPI 'vector' to 'target's via 'delivery_mode'.
574  *
575  * target is a bitmask of destination cpus.  Vector is any
576  * valid system INT vector.  Delivery mode may be either
577  * APIC_DELMODE_FIXED or APIC_DELMODE_LOWPRIO.
578  */
579 void
580 selected_apic_ipi(cpumask_t target, int vector, int delivery_mode)
581 {
582 	crit_enter();
583 	while (CPUMASK_TESTNZERO(target)) {
584 		int n = BSFCPUMASK(target);
585 		CPUMASK_NANDBIT(target, n);
586 		single_apic_ipi(n, vector, delivery_mode);
587 	}
588 	crit_exit();
589 }
590 
591 /*
592  * Timer code, in development...
593  *  - suggested by rgrimes@gndrsh.aac.dev.com
594  */
595 int
596 get_apic_timer_frequency(void)
597 {
598 	return(lapic_cputimer_intr.freq);
599 }
600 
601 /*
602  * Load a 'downcount time' in uSeconds.
603  */
604 void
605 set_apic_timer(int us)
606 {
607 	u_int count;
608 
609 	/*
610 	 * When we reach here, lapic timer's frequency
611 	 * must have been calculated as well as the
612 	 * divisor (lapic->dcr_timer is setup during the
613 	 * divisor calculation).
614 	 */
615 	KKASSERT(lapic_cputimer_intr.freq != 0 &&
616 		 lapic_timer_divisor_idx >= 0);
617 
618 	count = ((us * (int64_t)lapic_cputimer_intr.freq) + 999999) / 1000000;
619 	lapic_timer_oneshot(count);
620 }
621 
622 
623 /*
624  * Read remaining time in timer.
625  */
626 int
627 read_apic_timer(void)
628 {
629 #if 0
630 	/** XXX FIXME: we need to return the actual remaining time,
631          *         for now we just return the remaining count.
632          */
633 #else
634 	return lapic->ccr_timer;
635 #endif
636 }
637 
638 
639 /*
640  * Spin-style delay, set delay time in uS, spin till it drains.
641  */
642 void
643 u_sleep(int count)
644 {
645 	set_apic_timer(count);
646 	while (read_apic_timer())
647 		 /* spin */ ;
648 }
649 
650 int
651 lapic_unused_apic_id(int start)
652 {
653 	int i;
654 
655 	for (i = start; i < APICID_MAX; ++i) {
656 		if (APICID_TO_CPUID(i) == -1)
657 			return i;
658 	}
659 	return NAPICID;
660 }
661 
662 void
663 lapic_map(vm_paddr_t lapic_addr)
664 {
665 	lapic = pmap_mapdev_uncacheable(lapic_addr, sizeof(struct LAPIC));
666 }
667 
668 static TAILQ_HEAD(, lapic_enumerator) lapic_enumerators =
669 	TAILQ_HEAD_INITIALIZER(lapic_enumerators);
670 
671 int
672 lapic_config(void)
673 {
674 	struct lapic_enumerator *e;
675 	int error, i, ap_max;
676 
677 	KKASSERT(lapic_enable);
678 
679 	for (i = 0; i < NAPICID; ++i)
680 		APICID_TO_CPUID(i) = -1;
681 
682 	TAILQ_FOREACH(e, &lapic_enumerators, lapic_link) {
683 		error = e->lapic_probe(e);
684 		if (!error)
685 			break;
686 	}
687 	if (e == NULL) {
688 		kprintf("LAPIC: Can't find LAPIC\n");
689 		return ENXIO;
690 	}
691 
692 	error = e->lapic_enumerate(e);
693 	if (error) {
694 		kprintf("LAPIC: enumeration failed\n");
695 		return ENXIO;
696 	}
697 
698 	ap_max = MAXCPU - 1;
699 	TUNABLE_INT_FETCH("hw.ap_max", &ap_max);
700 	if (ap_max > MAXCPU - 1)
701 		ap_max = MAXCPU - 1;
702 
703 	if (naps > ap_max) {
704 		kprintf("LAPIC: Warning use only %d out of %d "
705 			"available APs\n",
706 			ap_max, naps);
707 		naps = ap_max;
708 	}
709 
710 	return 0;
711 }
712 
713 void
714 lapic_enumerator_register(struct lapic_enumerator *ne)
715 {
716 	struct lapic_enumerator *e;
717 
718 	TAILQ_FOREACH(e, &lapic_enumerators, lapic_link) {
719 		if (e->lapic_prio < ne->lapic_prio) {
720 			TAILQ_INSERT_BEFORE(e, ne, lapic_link);
721 			return;
722 		}
723 	}
724 	TAILQ_INSERT_TAIL(&lapic_enumerators, ne, lapic_link);
725 }
726 
727 void
728 lapic_set_cpuid(int cpu_id, int apic_id)
729 {
730 	CPUID_TO_APICID(cpu_id) = apic_id;
731 	APICID_TO_CPUID(apic_id) = cpu_id;
732 }
733 
734 void
735 lapic_fixup_noioapic(void)
736 {
737 	u_int   temp;
738 
739 	/* Only allowed on BSP */
740 	KKASSERT(mycpuid == 0);
741 	KKASSERT(!ioapic_enable);
742 
743 	temp = lapic->lvt_lint0;
744 	temp &= ~APIC_LVT_MASKED;
745 	lapic->lvt_lint0 = temp;
746 
747 	temp = lapic->lvt_lint1;
748 	temp |= APIC_LVT_MASKED;
749 	lapic->lvt_lint1 = temp;
750 }
751 
752 static void
753 lapic_sysinit(void *dummy __unused)
754 {
755 	if (lapic_enable) {
756 		int error;
757 
758 		error = lapic_config();
759 		if (error)
760 			lapic_enable = 0;
761 	}
762 
763 	if (lapic_enable) {
764 		/* Initialize BSP's local APIC */
765 		lapic_init(TRUE);
766 	} else if (ioapic_enable) {
767 		ioapic_enable = 0;
768 		icu_reinit_noioapic();
769 	}
770 }
771 SYSINIT(lapic, SI_BOOT2_LAPIC, SI_ORDER_FIRST, lapic_sysinit, NULL);
772