xref: /freebsd/sys/x86/x86/local_apic.c (revision 7b6be0014a4eb81943491122bae70914b7fd82b6)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1996, by Steve Passe
5  * All rights reserved.
6  * Copyright (c) 2003 John Baldwin <jhb@FreeBSD.org>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. The name of the developer may NOT be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  * 3. Neither the name of the author nor the names of any co-contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * Local APIC support on Pentium and later processors.
34  */
35 
36 #include <sys/cdefs.h>
37 #include "opt_atpic.h"
38 
39 #include "opt_ddb.h"
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/asan.h>
44 #include <sys/bus.h>
45 #include <sys/kernel.h>
46 #include <sys/lock.h>
47 #include <sys/malloc.h>
48 #include <sys/msan.h>
49 #include <sys/mutex.h>
50 #include <sys/pcpu.h>
51 #include <sys/proc.h>
52 #include <sys/refcount.h>
53 #include <sys/sched.h>
54 #include <sys/smp.h>
55 #include <sys/sysctl.h>
56 #include <sys/timeet.h>
57 #include <sys/timetc.h>
58 
59 #include <vm/vm.h>
60 #include <vm/pmap.h>
61 
62 #include <x86/apicreg.h>
63 #include <machine/clock.h>
64 #include <machine/cpufunc.h>
65 #include <machine/cputypes.h>
66 #include <machine/fpu.h>
67 #include <machine/frame.h>
68 #include <machine/intr_machdep.h>
69 #include <x86/apicvar.h>
70 #include <x86/mca.h>
71 #include <machine/md_var.h>
72 #include <machine/smp.h>
73 #include <machine/specialreg.h>
74 #include <x86/init.h>
75 #include <x86/kvm.h>
76 #include <contrib/xen/arch-x86/cpuid.h>
77 #include <x86/bhyve.h>
78 #include <dev/hyperv/vmbus/x86/hyperv_reg.h>
79 
80 #ifdef DDB
81 #include <sys/interrupt.h>
82 #include <ddb/ddb.h>
83 #endif
84 
85 #ifdef __amd64__
86 #define	SDT_APIC	SDT_SYSIGT
87 #define	GSEL_APIC	0
88 #else
89 #define	SDT_APIC	SDT_SYS386IGT
90 #define	GSEL_APIC	GSEL(GCODE_SEL, SEL_KPL)
91 #endif
92 
93 static MALLOC_DEFINE(M_LAPIC, "local_apic", "Local APIC items");
94 
95 /* Sanity checks on IDT vectors. */
96 CTASSERT(APIC_IO_INTS + APIC_NUM_IOINTS == APIC_TIMER_INT);
97 CTASSERT(APIC_TIMER_INT < APIC_LOCAL_INTS);
98 CTASSERT(APIC_LOCAL_INTS == 240);
99 CTASSERT(IPI_STOP < APIC_SPURIOUS_INT);
100 
101 /*
102  * I/O interrupts use non-negative IRQ values.  These values are used
103  * to mark unused IDT entries or IDT entries reserved for a non-I/O
104  * interrupt.
105  */
106 #define	IRQ_FREE	-1
107 #define	IRQ_TIMER	-2
108 #define	IRQ_SYSCALL	-3
109 #define	IRQ_DTRACE_RET	-4
110 #define	IRQ_EVTCHN	-5
111 
112 enum lat_timer_mode {
113 	LAT_MODE_UNDEF =	0,
114 	LAT_MODE_PERIODIC =	1,
115 	LAT_MODE_ONESHOT =	2,
116 	LAT_MODE_DEADLINE =	3,
117 };
118 
119 /*
120  * Support for local APICs.  Local APICs manage interrupts on each
121  * individual processor as opposed to I/O APICs which receive interrupts
122  * from I/O devices and then forward them on to the local APICs.
123  *
124  * Local APICs can also send interrupts to each other thus providing the
125  * mechanism for IPIs.
126  */
127 
128 struct lvt {
129 	u_int lvt_edgetrigger:1;
130 	u_int lvt_activehi:1;
131 	u_int lvt_masked:1;
132 	u_int lvt_active:1;
133 	u_int lvt_mode:16;
134 	u_int lvt_vector:8;
135 	u_int lvt_reg;
136 	const char *lvt_desc;
137 };
138 
139 struct lapic {
140 	struct lvt la_lvts[APIC_LVT_MAX + 1];
141 	struct lvt la_elvts[APIC_ELVT_MAX + 1];
142 	u_int la_id:8;
143 	u_int la_cluster:4;
144 	u_int la_cluster_id:2;
145 	u_int la_present:1;
146 	u_long *la_timer_count;
147 	uint64_t la_timer_period;
148 	enum lat_timer_mode la_timer_mode;
149 	uint32_t lvt_timer_base;
150 	uint32_t lvt_timer_last;
151 	/* Include IDT_SYSCALL to make indexing easier. */
152 	int la_ioint_irqs[APIC_NUM_IOINTS + 1];
153 } static *lapics;
154 
155 /* Global defaults for local APIC LVT entries. */
156 static struct lvt lvts[] = {
157 	/* LINT0: masked ExtINT */
158 	[APIC_LVT_LINT0] = {
159 		.lvt_edgetrigger = 1,
160 		.lvt_activehi = 1,
161 		.lvt_masked = 1,
162 		.lvt_active = 1,
163 		.lvt_mode = APIC_LVT_DM_EXTINT,
164 		.lvt_vector = 0,
165 		.lvt_reg = LAPIC_LVT_LINT0,
166 		.lvt_desc = "LINT0",
167 	},
168 	/* LINT1: NMI */
169 	[APIC_LVT_LINT1] = {
170 		.lvt_edgetrigger = 1,
171 		.lvt_activehi = 1,
172 		.lvt_masked = 0,
173 		.lvt_active = 1,
174 		.lvt_mode = APIC_LVT_DM_NMI,
175 		.lvt_vector = 0,
176 		.lvt_reg = LAPIC_LVT_LINT1,
177 		.lvt_desc = "LINT1",
178 	},
179 	[APIC_LVT_TIMER] = {
180 		.lvt_edgetrigger = 1,
181 		.lvt_activehi = 1,
182 		.lvt_masked = 1,
183 		.lvt_active = 1,
184 		.lvt_mode = APIC_LVT_DM_FIXED,
185 		.lvt_vector = APIC_TIMER_INT,
186 		.lvt_reg = LAPIC_LVT_TIMER,
187 		.lvt_desc = "TIMER",
188 	},
189 	[APIC_LVT_ERROR] = {
190 		.lvt_edgetrigger = 1,
191 		.lvt_activehi = 1,
192 		.lvt_masked = 0,
193 		.lvt_active = 1,
194 		.lvt_mode = APIC_LVT_DM_FIXED,
195 		.lvt_vector = APIC_ERROR_INT,
196 		.lvt_reg = LAPIC_LVT_ERROR,
197 		.lvt_desc = "ERROR",
198 	},
199 	[APIC_LVT_PMC] = {
200 		.lvt_edgetrigger = 1,
201 		.lvt_activehi = 1,
202 		.lvt_masked = 1,
203 		.lvt_active = 1,
204 		.lvt_mode = APIC_LVT_DM_NMI,
205 		.lvt_vector = 0,
206 		.lvt_reg = LAPIC_LVT_PCINT,
207 		.lvt_desc = "PMC",
208 	},
209 	[APIC_LVT_THERMAL] = {
210 		.lvt_edgetrigger = 1,
211 		.lvt_activehi = 1,
212 		.lvt_masked = 1,
213 		.lvt_active = 1,
214 		.lvt_mode = APIC_LVT_DM_FIXED,
215 		.lvt_vector = APIC_THERMAL_INT,
216 		.lvt_reg = LAPIC_LVT_THERMAL,
217 		.lvt_desc = "THERM",
218 	},
219 	[APIC_LVT_CMCI] = {
220 		.lvt_edgetrigger = 1,
221 		.lvt_activehi = 1,
222 		.lvt_masked = 1,
223 		.lvt_active = 1,
224 		.lvt_mode = APIC_LVT_DM_FIXED,
225 		.lvt_vector = APIC_CMC_INT,
226 		.lvt_reg = LAPIC_LVT_CMCI,
227 		.lvt_desc = "CMCI",
228 	},
229 };
230 
231 /* Global defaults for AMD local APIC ELVT entries. */
232 static struct lvt elvts[] = {
233 	[APIC_ELVT_IBS] = {
234 		.lvt_edgetrigger = 1,
235 		.lvt_activehi = 1,
236 		.lvt_masked = 1,
237 		.lvt_active = 1,
238 		.lvt_mode = APIC_LVT_DM_NMI,
239 		.lvt_vector = 0,
240 		.lvt_reg = LAPIC_EXT_LVT0,
241 		.lvt_desc = "IBS",
242 	},
243 	[APIC_ELVT_MCA] = {
244 		.lvt_edgetrigger = 1,
245 		.lvt_activehi = 1,
246 		.lvt_masked = 1,
247 		.lvt_active = 0,
248 		.lvt_mode = APIC_LVT_DM_FIXED,
249 		.lvt_vector = APIC_CMC_INT,
250 		.lvt_reg = LAPIC_EXT_LVT1,
251 		.lvt_desc = "MCA",
252 	},
253 	[APIC_ELVT_DEI] = {
254 		.lvt_edgetrigger = 1,
255 		.lvt_activehi = 1,
256 		.lvt_masked = 1,
257 		.lvt_active = 0,
258 		.lvt_mode = APIC_LVT_DM_FIXED,
259 		.lvt_vector = 0,
260 		.lvt_reg = LAPIC_EXT_LVT2,
261 		.lvt_desc = "ELVT2",
262 	},
263 	[APIC_ELVT_SBI] = {
264 		.lvt_edgetrigger = 1,
265 		.lvt_activehi = 1,
266 		.lvt_masked = 1,
267 		.lvt_active = 0,
268 		.lvt_mode = APIC_LVT_DM_FIXED,
269 		.lvt_vector = 0,
270 		.lvt_reg = LAPIC_EXT_LVT3,
271 		.lvt_desc = "ELVT3",
272 	},
273 };
274 
275 static inthand_t *ioint_handlers[] = {
276 	NULL,			/* 0 - 31 */
277 	IDTVEC(apic_isr1),	/* 32 - 63 */
278 	IDTVEC(apic_isr2),	/* 64 - 95 */
279 	IDTVEC(apic_isr3),	/* 96 - 127 */
280 	IDTVEC(apic_isr4),	/* 128 - 159 */
281 	IDTVEC(apic_isr5),	/* 160 - 191 */
282 	IDTVEC(apic_isr6),	/* 192 - 223 */
283 	IDTVEC(apic_isr7),	/* 224 - 255 */
284 };
285 
286 static inthand_t *ioint_pti_handlers[] = {
287 	NULL,			/* 0 - 31 */
288 	IDTVEC(apic_isr1_pti),	/* 32 - 63 */
289 	IDTVEC(apic_isr2_pti),	/* 64 - 95 */
290 	IDTVEC(apic_isr3_pti),	/* 96 - 127 */
291 	IDTVEC(apic_isr4_pti),	/* 128 - 159 */
292 	IDTVEC(apic_isr5_pti),	/* 160 - 191 */
293 	IDTVEC(apic_isr6_pti),	/* 192 - 223 */
294 	IDTVEC(apic_isr7_pti),	/* 224 - 255 */
295 };
296 
297 static u_int32_t lapic_timer_divisors[] = {
298 	APIC_TDCR_1, APIC_TDCR_2, APIC_TDCR_4, APIC_TDCR_8, APIC_TDCR_16,
299 	APIC_TDCR_32, APIC_TDCR_64, APIC_TDCR_128
300 };
301 
302 extern inthand_t IDTVEC(rsvd_pti), IDTVEC(rsvd);
303 
304 volatile char *lapic_map;
305 vm_paddr_t lapic_paddr = DEFAULT_APIC_BASE;
306 int x2apic_mode;
307 int lapic_eoi_suppression;
308 static int lapic_timer_tsc_deadline;
309 static u_long lapic_timer_divisor, count_freq;
310 static struct eventtimer lapic_et;
311 #ifdef SMP
312 static uint64_t lapic_ipi_wait_mult;
313 static int __read_mostly lapic_ds_idle_timeout = 1000000;
314 #endif
315 unsigned int max_apic_id;
316 static int pcint_refcnt = 0;
317 
318 SYSCTL_NODE(_hw, OID_AUTO, apic, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
319     "APIC options");
320 SYSCTL_INT(_hw_apic, OID_AUTO, x2apic_mode, CTLFLAG_RD, &x2apic_mode, 0, "");
321 SYSCTL_INT(_hw_apic, OID_AUTO, eoi_suppression, CTLFLAG_RD,
322     &lapic_eoi_suppression, 0, "");
323 SYSCTL_INT(_hw_apic, OID_AUTO, timer_tsc_deadline, CTLFLAG_RD,
324     &lapic_timer_tsc_deadline, 0, "");
325 #ifdef SMP
326 SYSCTL_INT(_hw_apic, OID_AUTO, ds_idle_timeout, CTLFLAG_RWTUN,
327     &lapic_ds_idle_timeout, 0,
328     "timeout (in us) for APIC Delivery Status to become Idle (xAPIC only)");
329 #endif
330 
331 static void lapic_calibrate_initcount(struct lapic *la);
332 
333 /*
334  * Calculate the max index of the present LVT entry from the value of
335  * the LAPIC version register.
336  */
337 static int
lapic_maxlvt(uint32_t version)338 lapic_maxlvt(uint32_t version)
339 {
340 	return ((version & APIC_VER_MAXLVT) >> MAXLVTSHIFT);
341 }
342 
343 /*
344  * Use __nosanitizethread to exempt the LAPIC I/O accessors from KCSan
345  * instrumentation.  Otherwise, if x2APIC is not available, use of the global
346  * lapic_map will generate a KCSan false positive.  While the mapping is
347  * shared among all CPUs, the physical access will always take place on the
348  * local CPU's APIC, so there isn't in fact a race here.  Furthermore, the
349  * KCSan warning printf can cause a panic if issued during LAPIC access,
350  * due to attempted recursive use of event timer resources.
351  */
352 
353 static uint32_t __nosanitizethread
lapic_read32(enum LAPIC_REGISTERS reg)354 lapic_read32(enum LAPIC_REGISTERS reg)
355 {
356 	uint32_t res;
357 
358 	if (x2apic_mode) {
359 		res = rdmsr32(MSR_APIC_000 + reg);
360 	} else {
361 		res = *(volatile uint32_t *)(lapic_map + reg * LAPIC_MEM_MUL);
362 	}
363 	return (res);
364 }
365 
366 static void __nosanitizethread
lapic_write32(enum LAPIC_REGISTERS reg,uint32_t val)367 lapic_write32(enum LAPIC_REGISTERS reg, uint32_t val)
368 {
369 
370 	if (x2apic_mode) {
371 		mfence();
372 		lfence();
373 		wrmsr(MSR_APIC_000 + reg, val);
374 	} else {
375 		*(volatile uint32_t *)(lapic_map + reg * LAPIC_MEM_MUL) = val;
376 	}
377 }
378 
379 static void __nosanitizethread
lapic_write32_nofence(enum LAPIC_REGISTERS reg,uint32_t val)380 lapic_write32_nofence(enum LAPIC_REGISTERS reg, uint32_t val)
381 {
382 
383 	if (x2apic_mode) {
384 		wrmsr(MSR_APIC_000 + reg, val);
385 	} else {
386 		*(volatile uint32_t *)(lapic_map + reg * LAPIC_MEM_MUL) = val;
387 	}
388 }
389 
390 #ifdef SMP
391 static uint64_t
lapic_read_icr_lo(void)392 lapic_read_icr_lo(void)
393 {
394 
395 	return (lapic_read32(LAPIC_ICR_LO));
396 }
397 
398 static void
lapic_write_icr(uint32_t vhi,uint32_t vlo)399 lapic_write_icr(uint32_t vhi, uint32_t vlo)
400 {
401 	register_t saveintr;
402 	uint64_t v;
403 
404 	if (x2apic_mode) {
405 		v = ((uint64_t)vhi << 32) | vlo;
406 		mfence();
407 		wrmsr(MSR_APIC_000 + LAPIC_ICR_LO, v);
408 	} else {
409 		saveintr = intr_disable();
410 		lapic_write32(LAPIC_ICR_HI, vhi);
411 		lapic_write32(LAPIC_ICR_LO, vlo);
412 		intr_restore(saveintr);
413 	}
414 }
415 
416 static void
lapic_write_icr_lo(uint32_t vlo)417 lapic_write_icr_lo(uint32_t vlo)
418 {
419 
420 	if (x2apic_mode) {
421 		mfence();
422 		wrmsr(MSR_APIC_000 + LAPIC_ICR_LO, vlo);
423 	} else {
424 		lapic_write32(LAPIC_ICR_LO, vlo);
425 	}
426 }
427 
428 static void
lapic_write_self_ipi(uint32_t vector)429 lapic_write_self_ipi(uint32_t vector)
430 {
431 
432 	KASSERT(x2apic_mode, ("SELF IPI write in xAPIC mode"));
433 	wrmsr(MSR_APIC_000 + LAPIC_SELF_IPI, vector);
434 }
435 #endif /* SMP */
436 
437 static void
lapic_enable_x2apic(void)438 lapic_enable_x2apic(void)
439 {
440 	uint64_t apic_base;
441 
442 	apic_base = rdmsr(MSR_APICBASE);
443 	apic_base |= APICBASE_X2APIC | APICBASE_ENABLED;
444 	wrmsr(MSR_APICBASE, apic_base);
445 }
446 
447 bool
lapic_is_x2apic(void)448 lapic_is_x2apic(void)
449 {
450 	uint64_t apic_base;
451 
452 	apic_base = rdmsr(MSR_APICBASE);
453 	return ((apic_base & (APICBASE_X2APIC | APICBASE_ENABLED)) ==
454 	    (APICBASE_X2APIC | APICBASE_ENABLED));
455 }
456 
457 static void	lapic_early_mask_vecs(void);
458 static void	lapic_enable(void);
459 static void	lapic_resume(struct pic *pic, bool suspend_cancelled);
460 static void	lapic_timer_oneshot(struct lapic *);
461 static void	lapic_timer_oneshot_nointr(struct lapic *, uint32_t);
462 static void	lapic_timer_periodic(struct lapic *);
463 static void	lapic_timer_deadline(struct lapic *);
464 static void	lapic_timer_stop(struct lapic *);
465 static void	lapic_timer_set_divisor(u_int divisor);
466 static uint32_t	lvt_mode(struct lapic *la, u_int pin, uint32_t value);
467 static int	lapic_et_start(struct eventtimer *et,
468 		    sbintime_t first, sbintime_t period);
469 static int	lapic_et_stop(struct eventtimer *et);
470 static u_int	apic_idt_to_irq(u_int apic_id, u_int vector);
471 static void	lapic_set_tpr(u_int vector);
472 
473 struct pic lapic_pic = { .pic_resume = lapic_resume };
474 
475 static uint32_t
lvt_mode_impl(struct lapic * la,struct lvt * lvt,u_int pin,uint32_t value)476 lvt_mode_impl(struct lapic *la, struct lvt *lvt, u_int pin, uint32_t value)
477 {
478 
479 	value &= ~(APIC_LVT_M | APIC_LVT_TM | APIC_LVT_IIPP | APIC_LVT_DM |
480 	    APIC_LVT_VECTOR);
481 	if (lvt->lvt_edgetrigger == 0)
482 		value |= APIC_LVT_TM;
483 	if (lvt->lvt_activehi == 0)
484 		value |= APIC_LVT_IIPP_INTALO;
485 	if (lvt->lvt_masked)
486 		value |= APIC_LVT_M;
487 	value |= lvt->lvt_mode;
488 	switch (lvt->lvt_mode) {
489 	case APIC_LVT_DM_NMI:
490 	case APIC_LVT_DM_SMI:
491 	case APIC_LVT_DM_INIT:
492 	case APIC_LVT_DM_EXTINT:
493 		if (!lvt->lvt_edgetrigger) {
494 			if (bootverbose) {
495 				printf(
496 				    "lapic%u: Forcing LINT%u to edge trigger\n",
497 				    la->la_id, pin);
498 			}
499 			value &= ~APIC_LVT_TM;
500 		}
501 		/* Use a vector of 0. */
502 		break;
503 	case APIC_LVT_DM_FIXED:
504 		value |= lvt->lvt_vector;
505 		break;
506 	default:
507 		panic("bad APIC LVT delivery mode: %#x\n", value);
508 	}
509 	return (value);
510 }
511 
512 static uint32_t
lvt_mode(struct lapic * la,u_int pin,uint32_t value)513 lvt_mode(struct lapic *la, u_int pin, uint32_t value)
514 {
515 	struct lvt *lvt;
516 
517 	KASSERT(pin <= APIC_LVT_MAX,
518 	    ("%s: pin %u out of range", __func__, pin));
519 	if (la->la_lvts[pin].lvt_active)
520 		lvt = &la->la_lvts[pin];
521 	else
522 		lvt = &lvts[pin];
523 
524 	return (lvt_mode_impl(la, lvt, pin, value));
525 }
526 
527 static uint32_t
elvt_mode(struct lapic * la,u_int idx,uint32_t value)528 elvt_mode(struct lapic *la, u_int idx, uint32_t value)
529 {
530 	struct lvt *elvt;
531 
532 	KASSERT(idx <= APIC_ELVT_MAX,
533 	    ("%s: idx %u out of range", __func__, idx));
534 
535 	if (la->la_elvts[idx].lvt_active)
536 	    elvt = &la->la_elvts[idx];
537 	else
538 	    elvt = &elvts[idx];
539 	KASSERT(elvt->lvt_active, ("%s: ELVT%u is not active", __func__, idx));
540 	KASSERT(elvt->lvt_edgetrigger,
541 	    ("%s: ELVT%u is not edge triggered", __func__, idx));
542 	KASSERT(elvt->lvt_activehi,
543 	    ("%s: ELVT%u is not active high", __func__, idx));
544 	return (lvt_mode_impl(la, elvt, idx, value));
545 }
546 
547 /*
548  * Map the local APIC and setup necessary interrupt vectors.
549  */
550 void
lapic_init(vm_paddr_t addr)551 lapic_init(vm_paddr_t addr)
552 {
553 #ifdef SMP
554 	uint64_t r, r1, r2, rx;
555 #endif
556 	uint32_t ver;
557 	int i;
558 	bool arat;
559 
560 	TSENTER();
561 
562 	/*
563 	 * Enable x2APIC mode if possible. Map the local APIC
564 	 * registers page.
565 	 *
566 	 * Keep the LAPIC registers page mapped uncached for x2APIC
567 	 * mode too, to have direct map page attribute set to
568 	 * uncached.  This is needed to work around CPU errata present
569 	 * on all Intel processors.
570 	 */
571 	KASSERT(trunc_page(addr) == addr,
572 	    ("local APIC not aligned on a page boundary"));
573 	lapic_paddr = addr;
574 	lapic_map = pmap_mapdev(addr, PAGE_SIZE);
575 	if (x2apic_mode) {
576 		lapic_enable_x2apic();
577 		lapic_map = NULL;
578 	}
579 
580 	/* Setup the spurious interrupt handler. */
581 	setidt(APIC_SPURIOUS_INT, IDTVEC(spuriousint), SDT_APIC, SEL_KPL,
582 	    GSEL_APIC);
583 
584 	/* Perform basic initialization of the BSP's local APIC. */
585 	lapic_enable();
586 	lapic_early_mask_vecs();
587 
588 	/* Set BSP's per-CPU local APIC ID. */
589 	PCPU_SET(apic_id, lapic_id());
590 
591 	/* Local APIC timer interrupt. */
592 	setidt(APIC_TIMER_INT, pti ? IDTVEC(timerint_pti) : IDTVEC(timerint),
593 	    SDT_APIC, SEL_KPL, GSEL_APIC);
594 
595 	/* Local APIC error interrupt. */
596 	setidt(APIC_ERROR_INT, pti ? IDTVEC(errorint_pti) : IDTVEC(errorint),
597 	    SDT_APIC, SEL_KPL, GSEL_APIC);
598 
599 	/* XXX: Thermal interrupt */
600 
601 	/* Local APIC CMCI. */
602 	setidt(APIC_CMC_INT, pti ? IDTVEC(cmcint_pti) : IDTVEC(cmcint),
603 	    SDT_APIC, SEL_KPL, GSEL_APIC);
604 
605 	if ((resource_int_value("apic", 0, "clock", &i) != 0 || i != 0)) {
606 		/* Set if APIC timer runs in C3. */
607 		arat = (cpu_power_eax & CPUTPM1_ARAT);
608 
609 		bzero(&lapic_et, sizeof(lapic_et));
610 		lapic_et.et_name = "LAPIC";
611 		lapic_et.et_flags = ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT |
612 		    ET_FLAGS_PERCPU;
613 		lapic_et.et_quality = 600;
614 		if (!arat) {
615 			lapic_et.et_flags |= ET_FLAGS_C3STOP;
616 			lapic_et.et_quality = 100;
617 		}
618 		if ((cpu_feature & CPUID_TSC) != 0 &&
619 		    (cpu_feature2 & CPUID2_TSCDLT) != 0 &&
620 		    tsc_is_invariant && tsc_freq != 0) {
621 			lapic_timer_tsc_deadline = 1;
622 			TUNABLE_INT_FETCH("hw.apic.timer_tsc_deadline",
623 			    &lapic_timer_tsc_deadline);
624 		}
625 
626 		lapic_et.et_frequency = 0;
627 		/* We don't know frequency yet, so trying to guess. */
628 		lapic_et.et_min_period = 0x00001000LL;
629 		lapic_et.et_max_period = SBT_1S;
630 		lapic_et.et_start = lapic_et_start;
631 		lapic_et.et_stop = lapic_et_stop;
632 		lapic_et.et_priv = NULL;
633 		et_register(&lapic_et);
634 	}
635 
636 	/*
637 	 * Set lapic_eoi_suppression after lapic_enable(), to not
638 	 * enable suppression in the hardware prematurely.  Note that
639 	 * we by default enable suppression even when system only has
640 	 * one IO-APIC, since EOI is broadcasted to all APIC agents,
641 	 * including CPUs, otherwise.
642 	 *
643 	 * It seems that at least some KVM versions report
644 	 * EOI_SUPPRESSION bit, but auto-EOI does not work.
645 	 */
646 	ver = lapic_read32(LAPIC_VERSION);
647 	if ((ver & APIC_VER_EOI_SUPPRESSION) != 0) {
648 		lapic_eoi_suppression = 1;
649 		if (vm_guest == VM_GUEST_KVM) {
650 			if (bootverbose)
651 				printf(
652 		       "KVM -- disabling lapic eoi suppression\n");
653 			lapic_eoi_suppression = 0;
654 		}
655 		TUNABLE_INT_FETCH("hw.apic.eoi_suppression",
656 		    &lapic_eoi_suppression);
657 	}
658 
659 #ifdef SMP
660 #define	LOOPS	1000
661 	/*
662 	 * Calibrate the busy loop waiting for IPI ack in xAPIC mode.
663 	 * lapic_ipi_wait_mult contains the number of iterations which
664 	 * approximately delay execution for 1 microsecond (the
665 	 * argument to lapic_ipi_wait() is in microseconds).
666 	 *
667 	 * We assume that TSC is present and already measured.
668 	 * Possible TSC frequency jumps are irrelevant to the
669 	 * calibration loop below, the CPU clock management code is
670 	 * not yet started, and we do not enter sleep states.
671 	 */
672 	KASSERT((cpu_feature & CPUID_TSC) != 0 && tsc_freq != 0,
673 	    ("TSC not initialized"));
674 	if (!x2apic_mode) {
675 		r = rdtsc();
676 		for (rx = 0; rx < LOOPS; rx++) {
677 			(void)lapic_read_icr_lo();
678 			ia32_pause();
679 		}
680 		r = rdtsc() - r;
681 		r1 = tsc_freq * LOOPS;
682 		r2 = r * 1000000;
683 		lapic_ipi_wait_mult = r1 >= r2 ? r1 / r2 : 1;
684 		if (bootverbose) {
685 			printf("LAPIC: ipi_wait() us multiplier %ju (r %ju "
686 			    "tsc %ju)\n", (uintmax_t)lapic_ipi_wait_mult,
687 			    (uintmax_t)r, (uintmax_t)tsc_freq);
688 		}
689 	}
690 #undef LOOPS
691 #endif /* SMP */
692 
693 	TSEXIT();
694 }
695 
696 /*
697  * Create a local APIC instance.
698  */
699 void
lapic_create(u_int apic_id,int boot_cpu)700 lapic_create(u_int apic_id, int boot_cpu)
701 {
702 	int i;
703 
704 	if (apic_id > max_apic_id) {
705 		printf("APIC: Ignoring local APIC with ID %d\n", apic_id);
706 		if (boot_cpu)
707 			panic("Can't ignore BSP");
708 		return;
709 	}
710 	KASSERT(!lapics[apic_id].la_present, ("duplicate local APIC %u",
711 	    apic_id));
712 
713 	/*
714 	 * Assume no local LVT overrides and a cluster of 0 and
715 	 * intra-cluster ID of 0.
716 	 */
717 	lapics[apic_id].la_present = 1;
718 	lapics[apic_id].la_id = apic_id;
719 	for (i = 0; i <= APIC_LVT_MAX; i++) {
720 		lapics[apic_id].la_lvts[i] = lvts[i];
721 		lapics[apic_id].la_lvts[i].lvt_active = 0;
722 	}
723 	for (i = 0; i <= APIC_ELVT_MAX; i++) {
724 		lapics[apic_id].la_elvts[i] = elvts[i];
725 		lapics[apic_id].la_elvts[i].lvt_active = 0;
726 	}
727 	for (i = 0; i <= APIC_NUM_IOINTS; i++)
728 	    lapics[apic_id].la_ioint_irqs[i] = IRQ_FREE;
729 	lapics[apic_id].la_ioint_irqs[IDT_SYSCALL - APIC_IO_INTS] = IRQ_SYSCALL;
730 	lapics[apic_id].la_ioint_irqs[APIC_TIMER_INT - APIC_IO_INTS] =
731 	    IRQ_TIMER;
732 #ifdef KDTRACE_HOOKS
733 	lapics[apic_id].la_ioint_irqs[IDT_DTRACE_RET - APIC_IO_INTS] =
734 	    IRQ_DTRACE_RET;
735 #endif
736 #ifdef XENHVM
737 	lapics[apic_id].la_ioint_irqs[IDT_EVTCHN - APIC_IO_INTS] = IRQ_EVTCHN;
738 #endif
739 
740 #ifdef SMP
741 	cpu_add(apic_id, boot_cpu);
742 #endif
743 }
744 
745 static inline uint32_t
amd_read_ext_features(void)746 amd_read_ext_features(void)
747 {
748 	uint32_t version;
749 
750 	if (cpu_vendor_id != CPU_VENDOR_AMD &&
751 	    cpu_vendor_id != CPU_VENDOR_HYGON)
752 		return (0);
753 	version = lapic_read32(LAPIC_VERSION);
754 	if ((version & APIC_VER_AMD_EXT_SPACE) != 0)
755 		return (lapic_read32(LAPIC_EXT_FEATURES));
756 	else
757 		return (0);
758 }
759 
760 static inline uint32_t
amd_read_elvt_count(void)761 amd_read_elvt_count(void)
762 {
763 	uint32_t extf;
764 	uint32_t count;
765 
766 	extf = amd_read_ext_features();
767 	count = (extf & APIC_EXTF_ELVT_MASK) >> APIC_EXTF_ELVT_SHIFT;
768 	count = min(count, APIC_ELVT_MAX + 1);
769 	return (count);
770 }
771 
772 /*
773  * Dump contents of local APIC registers
774  */
775 void
lapic_dump(const char * str)776 lapic_dump(const char* str)
777 {
778 	uint32_t version;
779 	uint32_t maxlvt;
780 	uint32_t extf;
781 	int elvt_count;
782 	int i;
783 
784 	version = lapic_read32(LAPIC_VERSION);
785 	maxlvt = lapic_maxlvt(version);
786 	printf("cpu%d %s:\n", PCPU_GET(cpuid), str);
787 	printf("     ID: 0x%08x   VER: 0x%08x LDR: 0x%08x DFR: 0x%08x",
788 	    lapic_read32(LAPIC_ID), version,
789 	    lapic_read32(LAPIC_LDR), x2apic_mode ? 0 : lapic_read32(LAPIC_DFR));
790 	if ((cpu_feature2 & CPUID2_X2APIC) != 0)
791 		printf(" x2APIC: %d", x2apic_mode);
792 	printf("\n  lint0: 0x%08x lint1: 0x%08x TPR: 0x%08x SVR: 0x%08x\n",
793 	    lapic_read32(LAPIC_LVT_LINT0), lapic_read32(LAPIC_LVT_LINT1),
794 	    lapic_read32(LAPIC_TPR), lapic_read32(LAPIC_SVR));
795 	printf("  timer: 0x%08x therm: 0x%08x err: 0x%08x",
796 	    lapic_read32(LAPIC_LVT_TIMER), lapic_read32(LAPIC_LVT_THERMAL),
797 	    lapic_read32(LAPIC_LVT_ERROR));
798 	if (maxlvt >= APIC_LVT_PMC)
799 		printf(" pmc: 0x%08x", lapic_read32(LAPIC_LVT_PCINT));
800 	printf("\n");
801 	if (maxlvt >= APIC_LVT_CMCI)
802 		printf("   cmci: 0x%08x\n", lapic_read32(LAPIC_LVT_CMCI));
803 	extf = amd_read_ext_features();
804 	if (extf != 0) {
805 		printf("   AMD ext features: 0x%08x", extf);
806 		elvt_count = amd_read_elvt_count();
807 		for (i = 0; i < elvt_count; i++)
808 			printf("%s elvt%d: 0x%08x", (i % 4) ? "" : "\n ", i,
809 			    lapic_read32(LAPIC_EXT_LVT0 + i));
810 		printf("\n");
811 	}
812 }
813 
814 void
lapic_xapic_mode(void)815 lapic_xapic_mode(void)
816 {
817 	register_t saveintr;
818 
819 	saveintr = intr_disable();
820 	if (x2apic_mode)
821 		lapic_enable_x2apic();
822 	intr_restore(saveintr);
823 }
824 
825 static void
lapic_early_mask_vec(const struct lvt * l)826 lapic_early_mask_vec(const struct lvt *l)
827 {
828 	uint32_t v;
829 
830 	if (l->lvt_masked != 0) {
831 		v = lapic_read32(l->lvt_reg);
832 		v |= APIC_LVT_M;
833 		lapic_write32(l->lvt_reg, v);
834 	}
835 }
836 
837 /* Done on BSP only */
838 static void
lapic_early_mask_vecs(void)839 lapic_early_mask_vecs(void)
840 {
841 	int elvt_count, lvts_count, i;
842 	uint32_t version;
843 
844 	version = lapic_read32(LAPIC_VERSION);
845 	lvts_count = min(nitems(lvts), lapic_maxlvt(version) + 1);
846 	for (i = 0; i < lvts_count; i++)
847 		lapic_early_mask_vec(&lvts[i]);
848 
849 	elvt_count = amd_read_elvt_count();
850 	for (i = 0; i < elvt_count; i++)
851 		lapic_early_mask_vec(&elvts[i]);
852 }
853 
854 void
lapic_setup(int boot)855 lapic_setup(int boot)
856 {
857 	struct lapic *la;
858 	uint32_t version;
859 	uint32_t maxlvt;
860 	register_t saveintr;
861 	int elvt_count;
862 	int i;
863 
864 	saveintr = intr_disable();
865 
866 	la = &lapics[lapic_id()];
867 	KASSERT(la->la_present, ("missing APIC structure"));
868 	version = lapic_read32(LAPIC_VERSION);
869 	maxlvt = lapic_maxlvt(version);
870 
871 	/* Initialize the TPR to allow all interrupts. */
872 	lapic_set_tpr(0);
873 
874 	/* Setup spurious vector and enable the local APIC. */
875 	lapic_enable();
876 
877 	/* Program LINT[01] LVT entries. */
878 	lapic_write32(LAPIC_LVT_LINT0, lvt_mode(la, APIC_LVT_LINT0,
879 	    lapic_read32(LAPIC_LVT_LINT0)));
880 	lapic_write32(LAPIC_LVT_LINT1, lvt_mode(la, APIC_LVT_LINT1,
881 	    lapic_read32(LAPIC_LVT_LINT1)));
882 
883 	/* Program the PMC LVT entry if present. */
884 	if (maxlvt >= APIC_LVT_PMC) {
885 		lapic_write32(LAPIC_LVT_PCINT, lvt_mode(la, APIC_LVT_PMC,
886 		    LAPIC_LVT_PCINT));
887 	}
888 
889 	/*
890 	 * Program the timer LVT.  Calibration is deferred until it is certain
891 	 * that we have a reliable timecounter.
892 	 */
893 	la->lvt_timer_base = lvt_mode(la, APIC_LVT_TIMER,
894 	    lapic_read32(LAPIC_LVT_TIMER));
895 	la->lvt_timer_last = la->lvt_timer_base;
896 	lapic_write32(LAPIC_LVT_TIMER, la->lvt_timer_base);
897 
898 	if (boot)
899 		la->la_timer_mode = LAT_MODE_UNDEF;
900 	else if (la->la_timer_mode != LAT_MODE_UNDEF) {
901 		KASSERT(la->la_timer_period != 0, ("lapic%u: zero divisor",
902 		    lapic_id()));
903 		switch (la->la_timer_mode) {
904 		case LAT_MODE_PERIODIC:
905 			lapic_timer_set_divisor(lapic_timer_divisor);
906 			lapic_timer_periodic(la);
907 			break;
908 		case LAT_MODE_ONESHOT:
909 			lapic_timer_set_divisor(lapic_timer_divisor);
910 			lapic_timer_oneshot(la);
911 			break;
912 		case LAT_MODE_DEADLINE:
913 			lapic_timer_deadline(la);
914 			break;
915 		default:
916 			panic("corrupted la_timer_mode %p %d", la,
917 			    la->la_timer_mode);
918 		}
919 	}
920 
921 	/* Program error LVT and clear any existing errors. */
922 	lapic_write32(LAPIC_LVT_ERROR, lvt_mode(la, APIC_LVT_ERROR,
923 	    lapic_read32(LAPIC_LVT_ERROR)));
924 	lapic_write32(LAPIC_ESR, 0);
925 
926 	/* XXX: Thermal LVT */
927 
928 	/* Program the CMCI LVT entry if present. */
929 	if (maxlvt >= APIC_LVT_CMCI) {
930 		lapic_write32(LAPIC_LVT_CMCI, lvt_mode(la, APIC_LVT_CMCI,
931 		    lapic_read32(LAPIC_LVT_CMCI)));
932 	}
933 
934 	elvt_count = amd_read_elvt_count();
935 	for (i = 0; i < elvt_count; i++) {
936 		if (la->la_elvts[i].lvt_active)
937 			lapic_write32(LAPIC_EXT_LVT0 + i,
938 			    elvt_mode(la, i, lapic_read32(LAPIC_EXT_LVT0 + i)));
939 	}
940 
941 	intr_restore(saveintr);
942 }
943 
944 static void
lapic_intrcnt(void * dummy __unused)945 lapic_intrcnt(void *dummy __unused)
946 {
947 	struct pcpu *pc;
948 	struct lapic *la;
949 	char buf[MAXCOMLEN + 1];
950 
951 	/* If there are no APICs, skip this function. */
952 	if (lapics == NULL)
953 		return;
954 
955 	STAILQ_FOREACH(pc, &cpuhead, pc_allcpu) {
956 		la = &lapics[pc->pc_apic_id];
957 		if (!la->la_present)
958 		    continue;
959 
960 		snprintf(buf, sizeof(buf), "cpu%d:timer", pc->pc_cpuid);
961 		intrcnt_add(buf, &la->la_timer_count);
962 	}
963 }
964 SYSINIT(lapic_intrcnt, SI_SUB_INTR, SI_ORDER_MIDDLE, lapic_intrcnt, NULL);
965 
966 void
lapic_reenable_pcint(void)967 lapic_reenable_pcint(void)
968 {
969 	uint32_t value;
970 
971 	if (refcount_load(&pcint_refcnt) == 0)
972 		return;
973 
974 	value = lapic_read32(LAPIC_LVT_PCINT);
975 	value &= ~APIC_LVT_M;
976 	lapic_write32(LAPIC_LVT_PCINT, value);
977 
978 	if ((amd_feature2 & AMDID2_IBS) != 0) {
979 		value = lapic_read32(LAPIC_EXT_LVT0);
980 		value &= ~APIC_LVT_M;
981 		lapic_write32(LAPIC_EXT_LVT0, value);
982 	}
983 }
984 
985 static void
lapic_update_pcint(void * dummy)986 lapic_update_pcint(void *dummy)
987 {
988 	struct lapic *la;
989 
990 	la = &lapics[lapic_id()];
991 	lapic_write32(LAPIC_LVT_PCINT, lvt_mode(la, APIC_LVT_PMC,
992 	    lapic_read32(LAPIC_LVT_PCINT)));
993 
994 	if ((amd_feature2 & AMDID2_IBS) != 0) {
995 		lapic_write32(LAPIC_EXT_LVT0, elvt_mode(la, APIC_ELVT_IBS,
996 		    lapic_read32(LAPIC_EXT_LVT0)));
997 	}
998 }
999 
1000 void
lapic_calibrate_timer(void)1001 lapic_calibrate_timer(void)
1002 {
1003 	struct lapic *la;
1004 	register_t intr;
1005 
1006 #ifdef DEV_ATPIC
1007 	/* Fail if the local APIC is not present. */
1008 	if (!x2apic_mode && lapic_map == NULL)
1009 		return;
1010 #endif
1011 
1012 	intr = intr_disable();
1013 	la = &lapics[lapic_id()];
1014 
1015 	lapic_calibrate_initcount(la);
1016 
1017 	intr_restore(intr);
1018 
1019 	if (lapic_timer_tsc_deadline && bootverbose) {
1020 		printf("lapic: deadline tsc mode, Frequency %ju Hz\n",
1021 		    (uintmax_t)tsc_freq);
1022 	}
1023 }
1024 
1025 int
lapic_enable_pcint(void)1026 lapic_enable_pcint(void)
1027 {
1028 	u_int32_t maxlvt;
1029 
1030 #ifdef DEV_ATPIC
1031 	/* Fail if the local APIC is not present. */
1032 	if (!x2apic_mode && lapic_map == NULL)
1033 		return (0);
1034 #endif
1035 
1036 	/* Fail if the PMC LVT is not present. */
1037 	maxlvt = lapic_maxlvt(lapic_read32(LAPIC_VERSION));
1038 	if (maxlvt < APIC_LVT_PMC)
1039 		return (0);
1040 	if (refcount_acquire(&pcint_refcnt) > 0)
1041 		return (1);
1042 	lvts[APIC_LVT_PMC].lvt_masked = 0;
1043 
1044 	if ((amd_feature2 & AMDID2_IBS) != 0)
1045 		elvts[APIC_ELVT_IBS].lvt_masked = 0;
1046 
1047 	MPASS(mp_ncpus == 1 || smp_started);
1048 	smp_rendezvous(NULL, lapic_update_pcint, NULL, NULL);
1049 	return (1);
1050 }
1051 
1052 void
lapic_disable_pcint(void)1053 lapic_disable_pcint(void)
1054 {
1055 	u_int32_t maxlvt;
1056 
1057 #ifdef DEV_ATPIC
1058 	/* Fail if the local APIC is not present. */
1059 	if (!x2apic_mode && lapic_map == NULL)
1060 		return;
1061 #endif
1062 
1063 	/* Fail if the PMC LVT is not present. */
1064 	maxlvt = lapic_maxlvt(lapic_read32(LAPIC_VERSION));
1065 	if (maxlvt < APIC_LVT_PMC)
1066 		return;
1067 	if (!refcount_release(&pcint_refcnt))
1068 		return;
1069 	lvts[APIC_LVT_PMC].lvt_masked = 1;
1070 	elvts[APIC_ELVT_IBS].lvt_masked = 1;
1071 
1072 #ifdef SMP
1073 	/* The APs should always be started when hwpmc is unloaded. */
1074 	KASSERT(mp_ncpus == 1 || smp_started, ("hwpmc unloaded too early"));
1075 #endif
1076 	smp_rendezvous(NULL, lapic_update_pcint, NULL, NULL);
1077 }
1078 
1079 static int
lapic_calibrate_initcount_cpuid_vm(void)1080 lapic_calibrate_initcount_cpuid_vm(void)
1081 {
1082 	u_int regs[4];
1083 	uint64_t freq;
1084 
1085 	/* Get value from CPUID leaf if possible. */
1086 	if (vm_guest == VM_GUEST_NO)
1087 		return (false);
1088 	if (hv_high < 0x40000010)
1089 		return (false);
1090 	do_cpuid(0x40000010, regs);
1091 	freq = (uint64_t)(regs[1]) * 1000;
1092 
1093 	/* Pick timer divisor. */
1094 	lapic_timer_divisor = 2;
1095 	do {
1096 		if (freq / lapic_timer_divisor < APIC_TIMER_MAX_COUNT)
1097 			break;
1098 		lapic_timer_divisor <<= 1;
1099 	} while (lapic_timer_divisor <= 128);
1100 	if (lapic_timer_divisor > 128)
1101 		return (false);
1102 
1103 	/* Record divided frequency. */
1104 	count_freq = freq / lapic_timer_divisor;
1105 	return (count_freq != 0);
1106 }
1107 
1108 static uint64_t
cb_lapic_getcount(void)1109 cb_lapic_getcount(void)
1110 {
1111 
1112 	return (APIC_TIMER_MAX_COUNT - lapic_read32(LAPIC_CCR_TIMER));
1113 }
1114 
1115 static void
lapic_calibrate_initcount(struct lapic * la)1116 lapic_calibrate_initcount(struct lapic *la)
1117 {
1118 	uint64_t freq;
1119 
1120 	if (lapic_calibrate_initcount_cpuid_vm())
1121 		goto done;
1122 
1123 	/* Calibrate the APIC timer frequency. */
1124 	lapic_timer_set_divisor(2);
1125 	lapic_timer_oneshot_nointr(la, APIC_TIMER_MAX_COUNT);
1126 	fpu_kern_enter(curthread, NULL, FPU_KERN_NOCTX);
1127 	freq = clockcalib(cb_lapic_getcount, "lapic");
1128 	fpu_kern_leave(curthread, NULL);
1129 
1130 	/* Pick a different divisor if necessary. */
1131 	lapic_timer_divisor = 2;
1132 	do {
1133 		if (freq * 2 / lapic_timer_divisor < APIC_TIMER_MAX_COUNT)
1134 			break;
1135 		lapic_timer_divisor <<= 1;
1136 	} while (lapic_timer_divisor <= 128);
1137 	if (lapic_timer_divisor > 128)
1138 		panic("lapic: Divisor too big");
1139 	count_freq = freq * 2 / lapic_timer_divisor;
1140 done:
1141 	if (bootverbose) {
1142 		printf("lapic: Divisor %lu, Frequency %lu Hz\n",
1143 		    lapic_timer_divisor, count_freq);
1144 	}
1145 }
1146 
1147 static void
lapic_change_mode(struct eventtimer * et,struct lapic * la,enum lat_timer_mode newmode)1148 lapic_change_mode(struct eventtimer *et, struct lapic *la,
1149     enum lat_timer_mode newmode)
1150 {
1151 	if (la->la_timer_mode == newmode)
1152 		return;
1153 	switch (newmode) {
1154 	case LAT_MODE_PERIODIC:
1155 		lapic_timer_set_divisor(lapic_timer_divisor);
1156 		et->et_frequency = count_freq;
1157 		break;
1158 	case LAT_MODE_DEADLINE:
1159 		et->et_frequency = tsc_freq;
1160 		break;
1161 	case LAT_MODE_ONESHOT:
1162 		lapic_timer_set_divisor(lapic_timer_divisor);
1163 		et->et_frequency = count_freq;
1164 		break;
1165 	default:
1166 		panic("lapic_change_mode %d", newmode);
1167 	}
1168 	la->la_timer_mode = newmode;
1169 	et->et_min_period = (0x00000002LLU << 32) / et->et_frequency;
1170 	et->et_max_period = (0xfffffffeLLU << 32) / et->et_frequency;
1171 }
1172 
1173 static int
lapic_et_start(struct eventtimer * et,sbintime_t first,sbintime_t period)1174 lapic_et_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
1175 {
1176 	struct lapic *la;
1177 
1178 	la = &lapics[PCPU_GET(apic_id)];
1179 	if (period != 0) {
1180 		lapic_change_mode(et, la, LAT_MODE_PERIODIC);
1181 		la->la_timer_period = ((uint32_t)et->et_frequency * period) >>
1182 		    32;
1183 		lapic_timer_periodic(la);
1184 	} else if (lapic_timer_tsc_deadline) {
1185 		lapic_change_mode(et, la, LAT_MODE_DEADLINE);
1186 		la->la_timer_period = (et->et_frequency * first) >> 32;
1187 		lapic_timer_deadline(la);
1188 	} else {
1189 		lapic_change_mode(et, la, LAT_MODE_ONESHOT);
1190 		la->la_timer_period = ((uint32_t)et->et_frequency * first) >>
1191 		    32;
1192 		lapic_timer_oneshot(la);
1193 	}
1194 	return (0);
1195 }
1196 
1197 static int
lapic_et_stop(struct eventtimer * et)1198 lapic_et_stop(struct eventtimer *et)
1199 {
1200 	struct lapic *la;
1201 
1202 	la = &lapics[PCPU_GET(apic_id)];
1203 	lapic_timer_stop(la);
1204 	la->la_timer_mode = LAT_MODE_UNDEF;
1205 	return (0);
1206 }
1207 
1208 void
lapic_disable(void)1209 lapic_disable(void)
1210 {
1211 	uint32_t value;
1212 
1213 	/* Software disable the local APIC. */
1214 	value = lapic_read32(LAPIC_SVR);
1215 	value &= ~APIC_SVR_SWEN;
1216 	lapic_write32(LAPIC_SVR, value);
1217 }
1218 
1219 static void
lapic_enable(void)1220 lapic_enable(void)
1221 {
1222 	uint32_t value;
1223 
1224 	/* Program the spurious vector to enable the local APIC. */
1225 	value = lapic_read32(LAPIC_SVR);
1226 	value &= ~(APIC_SVR_VECTOR | APIC_SVR_FOCUS);
1227 	value |= APIC_SVR_FEN | APIC_SVR_SWEN | APIC_SPURIOUS_INT;
1228 	if (lapic_eoi_suppression)
1229 		value |= APIC_SVR_EOI_SUPPRESSION;
1230 	lapic_write32(LAPIC_SVR, value);
1231 }
1232 
1233 /* Reset the local APIC on the BSP during resume. */
1234 static void
lapic_resume(struct pic * pic,bool suspend_cancelled)1235 lapic_resume(struct pic *pic, bool suspend_cancelled)
1236 {
1237 
1238 	lapic_setup(0);
1239 }
1240 
1241 int
lapic_id(void)1242 lapic_id(void)
1243 {
1244 	uint32_t v;
1245 
1246 	KASSERT(x2apic_mode || lapic_map != NULL, ("local APIC is not mapped"));
1247 	v = lapic_read32(LAPIC_ID);
1248 	if (!x2apic_mode)
1249 		v >>= APIC_ID_SHIFT;
1250 	return (v);
1251 }
1252 
1253 int
lapic_intr_pending(u_int vector)1254 lapic_intr_pending(u_int vector)
1255 {
1256 	uint32_t irr;
1257 
1258 	/*
1259 	 * The IRR registers are an array of registers each of which
1260 	 * only describes 32 interrupts in the low 32 bits.  Thus, we
1261 	 * divide the vector by 32 to get the register index.
1262 	 * Finally, we modulus the vector by 32 to determine the
1263 	 * individual bit to test.
1264 	 */
1265 	irr = lapic_read32(LAPIC_IRR0 + vector / 32);
1266 	return (irr & 1 << (vector % 32));
1267 }
1268 
1269 void
lapic_set_logical_id(u_int apic_id,u_int cluster,u_int cluster_id)1270 lapic_set_logical_id(u_int apic_id, u_int cluster, u_int cluster_id)
1271 {
1272 	struct lapic *la;
1273 
1274 	KASSERT(lapics[apic_id].la_present, ("%s: APIC %u doesn't exist",
1275 	    __func__, apic_id));
1276 	KASSERT(cluster <= APIC_MAX_CLUSTER, ("%s: cluster %u too big",
1277 	    __func__, cluster));
1278 	KASSERT(cluster_id <= APIC_MAX_INTRACLUSTER_ID,
1279 	    ("%s: intra cluster id %u too big", __func__, cluster_id));
1280 	la = &lapics[apic_id];
1281 	la->la_cluster = cluster;
1282 	la->la_cluster_id = cluster_id;
1283 }
1284 
1285 int
lapic_set_lvt_mask(u_int apic_id,u_int pin,u_char masked)1286 lapic_set_lvt_mask(u_int apic_id, u_int pin, u_char masked)
1287 {
1288 
1289 	if (pin > APIC_LVT_MAX)
1290 		return (EINVAL);
1291 	if (apic_id == APIC_ID_ALL) {
1292 		lvts[pin].lvt_masked = masked;
1293 		if (bootverbose)
1294 			printf("lapic:");
1295 	} else {
1296 		KASSERT(lapics[apic_id].la_present,
1297 		    ("%s: missing APIC %u", __func__, apic_id));
1298 		lapics[apic_id].la_lvts[pin].lvt_masked = masked;
1299 		lapics[apic_id].la_lvts[pin].lvt_active = 1;
1300 		if (bootverbose)
1301 			printf("lapic%u:", apic_id);
1302 	}
1303 	if (bootverbose)
1304 		printf(" LINT%u %s\n", pin, masked ? "masked" : "unmasked");
1305 	return (0);
1306 }
1307 
1308 int
lapic_set_lvt_mode(u_int apic_id,u_int pin,u_int32_t mode)1309 lapic_set_lvt_mode(u_int apic_id, u_int pin, u_int32_t mode)
1310 {
1311 	struct lvt *lvt;
1312 
1313 	if (pin > APIC_LVT_MAX)
1314 		return (EINVAL);
1315 	if (apic_id == APIC_ID_ALL) {
1316 		lvt = &lvts[pin];
1317 		if (bootverbose)
1318 			printf("lapic:");
1319 	} else {
1320 		KASSERT(lapics[apic_id].la_present,
1321 		    ("%s: missing APIC %u", __func__, apic_id));
1322 		lvt = &lapics[apic_id].la_lvts[pin];
1323 		lvt->lvt_active = 1;
1324 		if (bootverbose)
1325 			printf("lapic%u:", apic_id);
1326 	}
1327 	lvt->lvt_mode = mode;
1328 	switch (mode) {
1329 	case APIC_LVT_DM_NMI:
1330 	case APIC_LVT_DM_SMI:
1331 	case APIC_LVT_DM_INIT:
1332 	case APIC_LVT_DM_EXTINT:
1333 		lvt->lvt_edgetrigger = 1;
1334 		lvt->lvt_activehi = 1;
1335 		if (mode == APIC_LVT_DM_EXTINT)
1336 			lvt->lvt_masked = 1;
1337 		else
1338 			lvt->lvt_masked = 0;
1339 		break;
1340 	default:
1341 		panic("Unsupported delivery mode: 0x%x\n", mode);
1342 	}
1343 	if (bootverbose) {
1344 		printf(" Routing ");
1345 		switch (mode) {
1346 		case APIC_LVT_DM_NMI:
1347 			printf("NMI");
1348 			break;
1349 		case APIC_LVT_DM_SMI:
1350 			printf("SMI");
1351 			break;
1352 		case APIC_LVT_DM_INIT:
1353 			printf("INIT");
1354 			break;
1355 		case APIC_LVT_DM_EXTINT:
1356 			printf("ExtINT");
1357 			break;
1358 		}
1359 		printf(" -> LINT%u\n", pin);
1360 	}
1361 	return (0);
1362 }
1363 
1364 int
lapic_set_lvt_polarity(u_int apic_id,u_int pin,enum intr_polarity pol)1365 lapic_set_lvt_polarity(u_int apic_id, u_int pin, enum intr_polarity pol)
1366 {
1367 
1368 	if (pin > APIC_LVT_MAX || pol == INTR_POLARITY_CONFORM)
1369 		return (EINVAL);
1370 	if (apic_id == APIC_ID_ALL) {
1371 		lvts[pin].lvt_activehi = (pol == INTR_POLARITY_HIGH);
1372 		if (bootverbose)
1373 			printf("lapic:");
1374 	} else {
1375 		KASSERT(lapics[apic_id].la_present,
1376 		    ("%s: missing APIC %u", __func__, apic_id));
1377 		lapics[apic_id].la_lvts[pin].lvt_active = 1;
1378 		lapics[apic_id].la_lvts[pin].lvt_activehi =
1379 		    (pol == INTR_POLARITY_HIGH);
1380 		if (bootverbose)
1381 			printf("lapic%u:", apic_id);
1382 	}
1383 	if (bootverbose)
1384 		printf(" LINT%u polarity: %s\n", pin,
1385 		    pol == INTR_POLARITY_HIGH ? "high" : "low");
1386 	return (0);
1387 }
1388 
1389 int
lapic_set_lvt_triggermode(u_int apic_id,u_int pin,enum intr_trigger trigger)1390 lapic_set_lvt_triggermode(u_int apic_id, u_int pin,
1391      enum intr_trigger trigger)
1392 {
1393 
1394 	if (pin > APIC_LVT_MAX || trigger == INTR_TRIGGER_CONFORM)
1395 		return (EINVAL);
1396 	if (apic_id == APIC_ID_ALL) {
1397 		lvts[pin].lvt_edgetrigger = (trigger == INTR_TRIGGER_EDGE);
1398 		if (bootverbose)
1399 			printf("lapic:");
1400 	} else {
1401 		KASSERT(lapics[apic_id].la_present,
1402 		    ("%s: missing APIC %u", __func__, apic_id));
1403 		lapics[apic_id].la_lvts[pin].lvt_edgetrigger =
1404 		    (trigger == INTR_TRIGGER_EDGE);
1405 		lapics[apic_id].la_lvts[pin].lvt_active = 1;
1406 		if (bootverbose)
1407 			printf("lapic%u:", apic_id);
1408 	}
1409 	if (bootverbose)
1410 		printf(" LINT%u trigger: %s\n", pin,
1411 		    trigger == INTR_TRIGGER_EDGE ? "edge" : "level");
1412 	return (0);
1413 }
1414 
1415 /*
1416  * Adjust the TPR of the current CPU so that it blocks all interrupts below
1417  * the passed in vector.
1418  */
1419 static void
lapic_set_tpr(u_int vector)1420 lapic_set_tpr(u_int vector)
1421 {
1422 #ifdef CHEAP_TPR
1423 	lapic_write32(LAPIC_TPR, vector);
1424 #else
1425 	uint32_t tpr;
1426 
1427 	tpr = lapic_read32(LAPIC_TPR) & ~APIC_TPR_PRIO;
1428 	tpr |= vector;
1429 	lapic_write32(LAPIC_TPR, tpr);
1430 #endif
1431 }
1432 
1433 void
lapic_eoi(void)1434 lapic_eoi(void)
1435 {
1436 
1437 	lapic_write32_nofence(LAPIC_EOI, 0);
1438 }
1439 
1440 void
lapic_handle_intr(int vector,struct trapframe * frame)1441 lapic_handle_intr(int vector, struct trapframe *frame)
1442 {
1443 	struct intsrc *isrc;
1444 
1445 	kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
1446 	kmsan_mark(&vector, sizeof(vector), KMSAN_STATE_INITED);
1447 	kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);
1448 	trap_check_kstack();
1449 
1450 	isrc = intr_lookup_source(apic_idt_to_irq(PCPU_GET(apic_id),
1451 	    vector));
1452 	KASSERT(isrc != NULL,
1453 	    ("lapic_handle_intr: vector %d unrecognized at lapic %u",
1454 	    vector, PCPU_GET(apic_id)));
1455 	intr_execute_handlers(isrc, frame);
1456 }
1457 
1458 void
lapic_handle_timer(struct trapframe * frame)1459 lapic_handle_timer(struct trapframe *frame)
1460 {
1461 	struct lapic *la;
1462 	struct trapframe *oldframe;
1463 	struct thread *td;
1464 
1465 	/* Send EOI first thing. */
1466 	lapic_eoi();
1467 
1468 	kasan_mark(frame, sizeof(*frame), sizeof(*frame), 0);
1469 	kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);
1470 	trap_check_kstack();
1471 
1472 	if (!sched_do_timer_accounting())
1473 		return;
1474 
1475 	/* Look up our local APIC structure for the tick counters. */
1476 	la = &lapics[PCPU_GET(apic_id)];
1477 	(*la->la_timer_count)++;
1478 	critical_enter();
1479 	if (lapic_et.et_active) {
1480 		td = curthread;
1481 		td->td_intr_nesting_level++;
1482 		oldframe = td->td_intr_frame;
1483 		td->td_intr_frame = frame;
1484 		lapic_et.et_event_cb(&lapic_et, lapic_et.et_arg);
1485 		td->td_intr_frame = oldframe;
1486 		td->td_intr_nesting_level--;
1487 	}
1488 	critical_exit();
1489 }
1490 
1491 static void
lapic_timer_set_divisor(u_int divisor)1492 lapic_timer_set_divisor(u_int divisor)
1493 {
1494 
1495 	KASSERT(powerof2(divisor), ("lapic: invalid divisor %u", divisor));
1496 	KASSERT(ffs(divisor) <= nitems(lapic_timer_divisors),
1497 		("lapic: invalid divisor %u", divisor));
1498 	lapic_write32(LAPIC_DCR_TIMER, lapic_timer_divisors[ffs(divisor) - 1]);
1499 }
1500 
1501 static void
lapic_timer_oneshot(struct lapic * la)1502 lapic_timer_oneshot(struct lapic *la)
1503 {
1504 	uint32_t value;
1505 
1506 	value = la->lvt_timer_base;
1507 	value &= ~(APIC_LVTT_TM | APIC_LVT_M);
1508 	value |= APIC_LVTT_TM_ONE_SHOT;
1509 	la->lvt_timer_last = value;
1510 	lapic_write32(LAPIC_LVT_TIMER, value);
1511 	lapic_write32(LAPIC_ICR_TIMER, la->la_timer_period);
1512 }
1513 
1514 static void
lapic_timer_oneshot_nointr(struct lapic * la,uint32_t count)1515 lapic_timer_oneshot_nointr(struct lapic *la, uint32_t count)
1516 {
1517 	uint32_t value;
1518 
1519 	value = la->lvt_timer_base;
1520 	value &= ~APIC_LVTT_TM;
1521 	value |= APIC_LVTT_TM_ONE_SHOT | APIC_LVT_M;
1522 	la->lvt_timer_last = value;
1523 	lapic_write32(LAPIC_LVT_TIMER, value);
1524 	lapic_write32(LAPIC_ICR_TIMER, count);
1525 }
1526 
1527 static void
lapic_timer_periodic(struct lapic * la)1528 lapic_timer_periodic(struct lapic *la)
1529 {
1530 	uint32_t value;
1531 
1532 	value = la->lvt_timer_base;
1533 	value &= ~(APIC_LVTT_TM | APIC_LVT_M);
1534 	value |= APIC_LVTT_TM_PERIODIC;
1535 	la->lvt_timer_last = value;
1536 	lapic_write32(LAPIC_LVT_TIMER, value);
1537 	lapic_write32(LAPIC_ICR_TIMER, la->la_timer_period);
1538 }
1539 
1540 static void
lapic_timer_deadline(struct lapic * la)1541 lapic_timer_deadline(struct lapic *la)
1542 {
1543 	uint32_t value;
1544 
1545 	value = la->lvt_timer_base;
1546 	value &= ~(APIC_LVTT_TM | APIC_LVT_M);
1547 	value |= APIC_LVTT_TM_TSCDLT;
1548 	if (value != la->lvt_timer_last) {
1549 		la->lvt_timer_last = value;
1550 		lapic_write32_nofence(LAPIC_LVT_TIMER, value);
1551 		if (!x2apic_mode)
1552 			mfence();
1553 	}
1554 	wrmsr(MSR_TSC_DEADLINE, la->la_timer_period + rdtsc());
1555 }
1556 
1557 static void
lapic_timer_stop(struct lapic * la)1558 lapic_timer_stop(struct lapic *la)
1559 {
1560 	uint32_t value;
1561 
1562 	if (la->la_timer_mode == LAT_MODE_DEADLINE) {
1563 		wrmsr(MSR_TSC_DEADLINE, 0);
1564 		mfence();
1565 	} else {
1566 		value = la->lvt_timer_base;
1567 		value &= ~APIC_LVTT_TM;
1568 		value |= APIC_LVT_M;
1569 		la->lvt_timer_last = value;
1570 		lapic_write32(LAPIC_LVT_TIMER, value);
1571 	}
1572 }
1573 
1574 void
lapic_handle_cmc(void)1575 lapic_handle_cmc(void)
1576 {
1577 	trap_check_kstack();
1578 
1579 	lapic_eoi();
1580 	cmc_intr();
1581 }
1582 
1583 /*
1584  * Called from the mca_init() to activate the CMC interrupt if this CPU is
1585  * responsible for monitoring any MC banks for CMC events.  Since mca_init()
1586  * is called prior to lapic_setup() during boot, this just needs to unmask
1587  * this CPU's LVT_CMCI entry.
1588  */
1589 void
lapic_enable_cmc(void)1590 lapic_enable_cmc(void)
1591 {
1592 	u_int apic_id;
1593 
1594 #ifdef DEV_ATPIC
1595 	if (!x2apic_mode && lapic_map == NULL)
1596 		return;
1597 #endif
1598 	apic_id = PCPU_GET(apic_id);
1599 	KASSERT(lapics[apic_id].la_present,
1600 	    ("%s: missing APIC %u", __func__, apic_id));
1601 	lapics[apic_id].la_lvts[APIC_LVT_CMCI].lvt_masked = 0;
1602 	lapics[apic_id].la_lvts[APIC_LVT_CMCI].lvt_active = 1;
1603 }
1604 
1605 int
lapic_enable_mca_elvt(void)1606 lapic_enable_mca_elvt(void)
1607 {
1608 	u_int apic_id;
1609 	uint32_t value;
1610 	int elvt_count;
1611 
1612 #ifdef DEV_ATPIC
1613 	if (lapic_map == NULL)
1614 		return (-1);
1615 #endif
1616 
1617 	apic_id = PCPU_GET(apic_id);
1618 	KASSERT(lapics[apic_id].la_present,
1619 	    ("%s: missing APIC %u", __func__, apic_id));
1620 	elvt_count = amd_read_elvt_count();
1621 	if (elvt_count <= APIC_ELVT_MCA)
1622 		return (-1);
1623 
1624 	value = lapic_read32(LAPIC_EXT_LVT0 + APIC_ELVT_MCA);
1625 	if ((value & APIC_LVT_M) == 0) {
1626 		if (bootverbose)
1627 			printf("AMD MCE Thresholding Extended LVT is already active\n");
1628 		return (APIC_ELVT_MCA);
1629 	}
1630 	lapics[apic_id].la_elvts[APIC_ELVT_MCA].lvt_masked = 0;
1631 	lapics[apic_id].la_elvts[APIC_ELVT_MCA].lvt_active = 1;
1632 	return (APIC_ELVT_MCA);
1633 }
1634 
1635 void
lapic_handle_error(void)1636 lapic_handle_error(void)
1637 {
1638 	uint32_t esr;
1639 
1640 	trap_check_kstack();
1641 
1642 	/*
1643 	 * Read the contents of the error status register.  Write to
1644 	 * the register first before reading from it to force the APIC
1645 	 * to update its value to indicate any errors that have
1646 	 * occurred since the previous write to the register.
1647 	 */
1648 	lapic_write32(LAPIC_ESR, 0);
1649 	esr = lapic_read32(LAPIC_ESR);
1650 
1651 	printf("CPU%d: local APIC error 0x%x\n", PCPU_GET(cpuid), esr);
1652 	lapic_eoi();
1653 }
1654 
1655 u_int
apic_cpuid(u_int apic_id)1656 apic_cpuid(u_int apic_id)
1657 {
1658 #ifdef SMP
1659 	return apic_cpuids[apic_id];
1660 #else
1661 	return 0;
1662 #endif
1663 }
1664 
1665 /* Request a free IDT vector to be used by the specified IRQ. */
1666 u_int
apic_alloc_vector(u_int apic_id,u_int irq)1667 apic_alloc_vector(u_int apic_id, u_int irq)
1668 {
1669 	u_int vector;
1670 
1671 	KASSERT(irq < num_io_irqs, ("Invalid IRQ %u", irq));
1672 
1673 	/*
1674 	 * Search for a free vector.  Currently we just use a very simple
1675 	 * algorithm to find the first free vector.
1676 	 */
1677 	mtx_lock_spin(&icu_lock);
1678 	for (vector = 0; vector < APIC_NUM_IOINTS; vector++) {
1679 		if (lapics[apic_id].la_ioint_irqs[vector] != IRQ_FREE)
1680 			continue;
1681 		lapics[apic_id].la_ioint_irqs[vector] = irq;
1682 		mtx_unlock_spin(&icu_lock);
1683 		return (vector + APIC_IO_INTS);
1684 	}
1685 	mtx_unlock_spin(&icu_lock);
1686 	return (0);
1687 }
1688 
1689 /*
1690  * Request 'count' free contiguous IDT vectors to be used by 'count'
1691  * IRQs.  'count' must be a power of two and the vectors will be
1692  * aligned on a boundary of 'align'.  If the request cannot be
1693  * satisfied, 0 is returned.
1694  */
1695 u_int
apic_alloc_vectors(u_int apic_id,u_int * irqs,u_int count,u_int align)1696 apic_alloc_vectors(u_int apic_id, u_int *irqs, u_int count, u_int align)
1697 {
1698 	u_int first, run, vector;
1699 
1700 	KASSERT(powerof2(count), ("bad count"));
1701 	KASSERT(powerof2(align), ("bad align"));
1702 	KASSERT(align >= count, ("align < count"));
1703 #ifdef INVARIANTS
1704 	for (run = 0; run < count; run++)
1705 		KASSERT(irqs[run] < num_io_irqs, ("Invalid IRQ %u at index %u",
1706 		    irqs[run], run));
1707 #endif
1708 
1709 	/*
1710 	 * Search for 'count' free vectors.  As with apic_alloc_vector(),
1711 	 * this just uses a simple first fit algorithm.
1712 	 */
1713 	run = 0;
1714 	first = 0;
1715 	mtx_lock_spin(&icu_lock);
1716 	for (vector = 0; vector < APIC_NUM_IOINTS; vector++) {
1717 		/* Vector is in use, end run. */
1718 		if (lapics[apic_id].la_ioint_irqs[vector] != IRQ_FREE) {
1719 			run = 0;
1720 			first = 0;
1721 			continue;
1722 		}
1723 
1724 		/* Start a new run if run == 0 and vector is aligned. */
1725 		if (run == 0) {
1726 			if (((vector + APIC_IO_INTS) & (align - 1)) != 0)
1727 				continue;
1728 			first = vector;
1729 		}
1730 		run++;
1731 
1732 		/* Keep looping if the run isn't long enough yet. */
1733 		if (run < count)
1734 			continue;
1735 
1736 		/* Found a run, assign IRQs and return the first vector. */
1737 		for (vector = 0; vector < count; vector++)
1738 			lapics[apic_id].la_ioint_irqs[first + vector] =
1739 			    irqs[vector];
1740 		mtx_unlock_spin(&icu_lock);
1741 		return (first + APIC_IO_INTS);
1742 	}
1743 	mtx_unlock_spin(&icu_lock);
1744 	printf("APIC: Couldn't find APIC vectors for %u IRQs\n", count);
1745 	return (0);
1746 }
1747 
1748 /*
1749  * Enable a vector for a particular apic_id.  Since all lapics share idt
1750  * entries and ioint_handlers this enables the vector on all lapics.  lapics
1751  * which do not have the vector configured would report spurious interrupts
1752  * should it fire.
1753  */
1754 void
apic_enable_vector(u_int apic_id,u_int vector)1755 apic_enable_vector(u_int apic_id, u_int vector)
1756 {
1757 
1758 	KASSERT(vector != IDT_SYSCALL, ("Attempt to overwrite syscall entry"));
1759 	KASSERT(ioint_handlers[vector / 32] != NULL,
1760 	    ("No ISR handler for vector %u", vector));
1761 #ifdef KDTRACE_HOOKS
1762 	KASSERT(vector != IDT_DTRACE_RET,
1763 	    ("Attempt to overwrite DTrace entry"));
1764 #endif
1765 	setidt(vector, (pti ? ioint_pti_handlers : ioint_handlers)[vector / 32],
1766 	    SDT_APIC, SEL_KPL, GSEL_APIC);
1767 }
1768 
1769 void
apic_disable_vector(u_int apic_id,u_int vector)1770 apic_disable_vector(u_int apic_id, u_int vector)
1771 {
1772 
1773 	KASSERT(vector != IDT_SYSCALL, ("Attempt to overwrite syscall entry"));
1774 #ifdef KDTRACE_HOOKS
1775 	KASSERT(vector != IDT_DTRACE_RET,
1776 	    ("Attempt to overwrite DTrace entry"));
1777 #endif
1778 	KASSERT(ioint_handlers[vector / 32] != NULL,
1779 	    ("No ISR handler for vector %u", vector));
1780 #ifdef notyet
1781 	/*
1782 	 * We can not currently clear the idt entry because other cpus
1783 	 * may have a valid vector at this offset.
1784 	 */
1785 	setidt(vector, pti ? &IDTVEC(rsvd_pti) : &IDTVEC(rsvd), SDT_APIC,
1786 	    SEL_KPL, GSEL_APIC);
1787 #endif
1788 }
1789 
1790 /* Release an APIC vector when it's no longer in use. */
1791 void
apic_free_vector(u_int apic_id,u_int vector,u_int irq)1792 apic_free_vector(u_int apic_id, u_int vector, u_int irq)
1793 {
1794 	struct thread *td;
1795 
1796 	KASSERT(vector >= APIC_IO_INTS && vector != IDT_SYSCALL &&
1797 	    vector <= APIC_IO_INTS + APIC_NUM_IOINTS,
1798 	    ("Vector %u does not map to an IRQ line", vector));
1799 	KASSERT(irq < num_io_irqs, ("Invalid IRQ %u", irq));
1800 	KASSERT(lapics[apic_id].la_ioint_irqs[vector - APIC_IO_INTS] ==
1801 	    irq, ("IRQ mismatch"));
1802 #ifdef KDTRACE_HOOKS
1803 	KASSERT(vector != IDT_DTRACE_RET,
1804 	    ("Attempt to overwrite DTrace entry"));
1805 #endif
1806 
1807 	/*
1808 	 * Bind us to the cpu that owned the vector before freeing it so
1809 	 * we don't lose an interrupt delivery race.
1810 	 */
1811 	td = curthread;
1812 	if (!rebooting) {
1813 		thread_lock(td);
1814 		if (sched_is_bound(td))
1815 			panic("apic_free_vector: Thread already bound.\n");
1816 		sched_bind(td, apic_cpuid(apic_id));
1817 		thread_unlock(td);
1818 	}
1819 	mtx_lock_spin(&icu_lock);
1820 	lapics[apic_id].la_ioint_irqs[vector - APIC_IO_INTS] = IRQ_FREE;
1821 	mtx_unlock_spin(&icu_lock);
1822 	if (!rebooting) {
1823 		thread_lock(td);
1824 		sched_unbind(td);
1825 		thread_unlock(td);
1826 	}
1827 }
1828 
1829 /* Map an IDT vector (APIC) to an IRQ (interrupt source). */
1830 static u_int
apic_idt_to_irq(u_int apic_id,u_int vector)1831 apic_idt_to_irq(u_int apic_id, u_int vector)
1832 {
1833 	int irq;
1834 
1835 	KASSERT(vector >= APIC_IO_INTS && vector != IDT_SYSCALL &&
1836 	    vector <= APIC_IO_INTS + APIC_NUM_IOINTS,
1837 	    ("Vector %u does not map to an IRQ line", vector));
1838 #ifdef KDTRACE_HOOKS
1839 	KASSERT(vector != IDT_DTRACE_RET,
1840 	    ("Attempt to overwrite DTrace entry"));
1841 #endif
1842 	irq = lapics[apic_id].la_ioint_irqs[vector - APIC_IO_INTS];
1843 	if (irq < 0)
1844 		irq = 0;
1845 	return (irq);
1846 }
1847 
1848 #ifdef DDB
1849 /*
1850  * Dump data about APIC IDT vector mappings.
1851  */
DB_SHOW_COMMAND_FLAGS(apic,db_show_apic,DB_CMD_MEMSAFE)1852 DB_SHOW_COMMAND_FLAGS(apic, db_show_apic, DB_CMD_MEMSAFE)
1853 {
1854 	struct intsrc *isrc;
1855 	int i, verbose;
1856 	u_int apic_id;
1857 	u_int irq;
1858 
1859 	if (strcmp(modif, "vv") == 0)
1860 		verbose = 2;
1861 	else if (strcmp(modif, "v") == 0)
1862 		verbose = 1;
1863 	else
1864 		verbose = 0;
1865 	for (apic_id = 0; apic_id <= max_apic_id; apic_id++) {
1866 		if (lapics[apic_id].la_present == 0)
1867 			continue;
1868 		db_printf("Interrupts bound to lapic %u\n", apic_id);
1869 		for (i = 0; i < APIC_NUM_IOINTS + 1 && !db_pager_quit; i++) {
1870 			irq = lapics[apic_id].la_ioint_irqs[i];
1871 			if (irq == IRQ_FREE || irq == IRQ_SYSCALL)
1872 				continue;
1873 #ifdef KDTRACE_HOOKS
1874 			if (irq == IRQ_DTRACE_RET)
1875 				continue;
1876 #endif
1877 #ifdef XENHVM
1878 			if (irq == IRQ_EVTCHN)
1879 				continue;
1880 #endif
1881 			db_printf("vec 0x%2x -> ", i + APIC_IO_INTS);
1882 			if (irq == IRQ_TIMER)
1883 				db_printf("lapic timer\n");
1884 			else if (irq < num_io_irqs) {
1885 				isrc = intr_lookup_source(irq);
1886 				if (isrc == NULL || verbose == 0)
1887 					db_printf("IRQ %u\n", irq);
1888 				else
1889 					db_dump_intr_event(isrc->is_event,
1890 					    verbose == 2);
1891 			} else
1892 				db_printf("IRQ %u ???\n", irq);
1893 		}
1894 	}
1895 }
1896 
1897 static void
dump_mask(const char * prefix,uint32_t v,int base)1898 dump_mask(const char *prefix, uint32_t v, int base)
1899 {
1900 	int i, first;
1901 
1902 	first = 1;
1903 	for (i = 0; i < 32; i++)
1904 		if (v & (1 << i)) {
1905 			if (first) {
1906 				db_printf("%s:", prefix);
1907 				first = 0;
1908 			}
1909 			db_printf(" %02x", base + i);
1910 		}
1911 	if (!first)
1912 		db_printf("\n");
1913 }
1914 
1915 /* Show info from the lapic regs for this CPU. */
DB_SHOW_COMMAND_FLAGS(lapic,db_show_lapic,DB_CMD_MEMSAFE)1916 DB_SHOW_COMMAND_FLAGS(lapic, db_show_lapic, DB_CMD_MEMSAFE)
1917 {
1918 	const struct lvt *l;
1919 	int elvt_count, lvts_count, i;
1920 	uint32_t v, vr;
1921 
1922 	db_printf("lapic ID = %d\n", lapic_id());
1923 	v = lapic_read32(LAPIC_VERSION);
1924 	db_printf("version  = %d.%d (%#x) \n", (v & APIC_VER_VERSION) >> 4,
1925 	    v & 0xf, v);
1926 	db_printf("max LVT  = %d\n", lapic_maxlvt(v));
1927 	vr = lapic_read32(LAPIC_SVR);
1928 	db_printf("SVR      = %02x (%s)\n", vr & APIC_SVR_VECTOR,
1929 	    vr & APIC_SVR_ENABLE ? "enabled" : "disabled");
1930 	db_printf("TPR      = %02x\n", lapic_read32(LAPIC_TPR));
1931 
1932 	lvts_count = min(nitems(lvts), lapic_maxlvt(v) + 1);
1933 	for (i = 0; i < lvts_count; i++) {
1934 		l = &lvts[i];
1935 		db_printf("LVT%d  (reg %#x %-5s) = %#010x\n", i, l->lvt_reg,
1936 		    l->lvt_desc, lapic_read32(l->lvt_reg));
1937 	}
1938 
1939 	elvt_count = amd_read_elvt_count();
1940 	for (i = 0; i < elvt_count; i++) {
1941 		l = &elvts[i];
1942 		db_printf("ELVT%d (reg %#x %-5s) = %#010x\n", i, l->lvt_reg,
1943 		    l->lvt_desc, lapic_read32(l->lvt_reg));
1944 	}
1945 
1946 #define dump_field(prefix, regn, index)					\
1947 	dump_mask(__XSTRING(prefix ## index), 				\
1948 	    lapic_read32(LAPIC_ ## regn ## index),			\
1949 	    index * 32)
1950 
1951 	db_printf("In-service Interrupts:\n");
1952 	dump_field(isr, ISR, 0);
1953 	dump_field(isr, ISR, 1);
1954 	dump_field(isr, ISR, 2);
1955 	dump_field(isr, ISR, 3);
1956 	dump_field(isr, ISR, 4);
1957 	dump_field(isr, ISR, 5);
1958 	dump_field(isr, ISR, 6);
1959 	dump_field(isr, ISR, 7);
1960 
1961 	db_printf("TMR Interrupts:\n");
1962 	dump_field(tmr, TMR, 0);
1963 	dump_field(tmr, TMR, 1);
1964 	dump_field(tmr, TMR, 2);
1965 	dump_field(tmr, TMR, 3);
1966 	dump_field(tmr, TMR, 4);
1967 	dump_field(tmr, TMR, 5);
1968 	dump_field(tmr, TMR, 6);
1969 	dump_field(tmr, TMR, 7);
1970 
1971 	db_printf("IRR Interrupts:\n");
1972 	dump_field(irr, IRR, 0);
1973 	dump_field(irr, IRR, 1);
1974 	dump_field(irr, IRR, 2);
1975 	dump_field(irr, IRR, 3);
1976 	dump_field(irr, IRR, 4);
1977 	dump_field(irr, IRR, 5);
1978 	dump_field(irr, IRR, 6);
1979 	dump_field(irr, IRR, 7);
1980 
1981 #undef dump_field
1982 }
1983 #endif
1984 
1985 /*
1986  * APIC probing support code.  This includes code to manage enumerators.
1987  */
1988 
1989 static SLIST_HEAD(, apic_enumerator) enumerators =
1990 	SLIST_HEAD_INITIALIZER(enumerators);
1991 static struct apic_enumerator *best_enum;
1992 
1993 void
apic_register_enumerator(struct apic_enumerator * enumerator)1994 apic_register_enumerator(struct apic_enumerator *enumerator)
1995 {
1996 #ifdef INVARIANTS
1997 	struct apic_enumerator *apic_enum;
1998 
1999 	SLIST_FOREACH(apic_enum, &enumerators, apic_next) {
2000 		if (apic_enum == enumerator)
2001 			panic("%s: Duplicate register of %s", __func__,
2002 			    enumerator->apic_name);
2003 	}
2004 #endif
2005 	SLIST_INSERT_HEAD(&enumerators, enumerator, apic_next);
2006 }
2007 
2008 /*
2009  * We have to look for CPU's very, very early because certain subsystems
2010  * want to know how many CPU's we have extremely early on in the boot
2011  * process.
2012  */
2013 static void
apic_init(void * dummy __unused)2014 apic_init(void *dummy __unused)
2015 {
2016 	struct apic_enumerator *enumerator;
2017 	int retval, best;
2018 
2019 	/* We only support built in local APICs. */
2020 	if (!(cpu_feature & CPUID_APIC))
2021 		return;
2022 
2023 	/* Don't probe if APIC mode is disabled. */
2024 	if (resource_disabled("apic", 0))
2025 		return;
2026 
2027 	/* Probe all the enumerators to find the best match. */
2028 	best_enum = NULL;
2029 	best = 0;
2030 	SLIST_FOREACH(enumerator, &enumerators, apic_next) {
2031 		retval = enumerator->apic_probe();
2032 		if (retval > 0)
2033 			continue;
2034 		if (best_enum == NULL || best < retval) {
2035 			best_enum = enumerator;
2036 			best = retval;
2037 		}
2038 	}
2039 	if (best_enum == NULL) {
2040 		if (bootverbose)
2041 			printf("APIC: Could not find any APICs.\n");
2042 #ifndef DEV_ATPIC
2043 		panic("running without device atpic requires a local APIC");
2044 #endif
2045 		return;
2046 	}
2047 
2048 	if (bootverbose)
2049 		printf("APIC: Using the %s enumerator.\n",
2050 		    best_enum->apic_name);
2051 
2052 #ifdef I686_CPU
2053 	/*
2054 	 * To work around an errata, we disable the local APIC on some
2055 	 * CPUs during early startup.  We need to turn the local APIC back
2056 	 * on on such CPUs now.
2057 	 */
2058 	ppro_reenable_apic();
2059 #endif
2060 
2061 	/* Probe the CPU's in the system. */
2062 	retval = best_enum->apic_probe_cpus();
2063 	if (retval != 0)
2064 		printf("%s: Failed to probe CPUs: returned %d\n",
2065 		    best_enum->apic_name, retval);
2066 
2067 }
2068 SYSINIT(apic_init, SI_SUB_TUNABLES - 1, SI_ORDER_SECOND, apic_init, NULL);
2069 
2070 /*
2071  * Setup the local APIC.  We have to do this prior to starting up the APs
2072  * in the SMP case.
2073  */
2074 static void
apic_setup_local(void * dummy __unused)2075 apic_setup_local(void *dummy __unused)
2076 {
2077 	int retval;
2078 
2079 	if (best_enum == NULL)
2080 		return;
2081 
2082 	lapics = malloc(sizeof(*lapics) * (max_apic_id + 1), M_LAPIC,
2083 	    M_WAITOK | M_ZERO);
2084 
2085 	/* Initialize the local APIC. */
2086 	retval = best_enum->apic_setup_local();
2087 	if (retval != 0)
2088 		printf("%s: Failed to setup the local APIC: returned %d\n",
2089 		    best_enum->apic_name, retval);
2090 }
2091 SYSINIT(apic_setup_local, SI_SUB_CPU, SI_ORDER_SECOND, apic_setup_local, NULL);
2092 
2093 /* Are we in a VM which supports the Extended Destination ID standard? */
2094 int apic_ext_dest_id = -1;
2095 SYSCTL_INT(_machdep, OID_AUTO, apic_ext_dest_id, CTLFLAG_RDTUN, &apic_ext_dest_id, 0,
2096     "Use APIC Extended Destination IDs");
2097 
2098 /* Detect support for Extended Destination IDs. */
2099 static void
detect_extended_dest_id(void)2100 detect_extended_dest_id(void)
2101 {
2102 	u_int regs[4];
2103 
2104 	/* Check if we support extended destination IDs. */
2105 	switch (vm_guest) {
2106 	case VM_GUEST_XEN:
2107 		cpuid_count(hv_base + 4, 0, regs);
2108 		if (regs[0] & XEN_HVM_CPUID_EXT_DEST_ID)
2109 			apic_ext_dest_id = 1;
2110 		break;
2111 	case VM_GUEST_HV:
2112 		cpuid_count(CPUID_LEAF_HV_STACK_INTERFACE, 0, regs);
2113 		if (regs[0] != HYPERV_STACK_INTERFACE_EAX_SIG)
2114 			break;
2115 		cpuid_count(CPUID_LEAF_HV_STACK_PROPERTIES, 0, regs);
2116 		if (regs[0] & HYPERV_PROPERTIES_EXT_DEST_ID)
2117 			apic_ext_dest_id = 1;
2118 		break;
2119 	case VM_GUEST_KVM:
2120 		kvm_cpuid_get_features(regs);
2121 		if (regs[0] & KVM_FEATURE_MSI_EXT_DEST_ID)
2122 			apic_ext_dest_id = 1;
2123 		break;
2124 	case VM_GUEST_BHYVE:
2125 		if (hv_high < CPUID_BHYVE_FEATURES)
2126 			break;
2127 		cpuid_count(CPUID_BHYVE_FEATURES, 0, regs);
2128 		if (regs[0] & CPUID_BHYVE_FEAT_EXT_DEST_ID)
2129 			apic_ext_dest_id = 1;
2130 		break;
2131 	}
2132 }
2133 
2134 /*
2135  * Setup the I/O APICs.
2136  */
2137 static void
apic_setup_io(void * dummy __unused)2138 apic_setup_io(void *dummy __unused)
2139 {
2140 	int retval;
2141 
2142 	if (best_enum == NULL)
2143 		return;
2144 
2145 	/* Check hypervisor support for extended destination IDs. */
2146 	if (apic_ext_dest_id == -1)
2147 		detect_extended_dest_id();
2148 
2149 	/*
2150 	 * Local APIC must be registered before other PICs and pseudo PICs
2151 	 * for proper suspend/resume order.
2152 	 */
2153 	intr_register_pic(&lapic_pic);
2154 
2155 	retval = best_enum->apic_setup_io();
2156 	if (retval != 0)
2157 		printf("%s: Failed to setup I/O APICs: returned %d\n",
2158 		    best_enum->apic_name, retval);
2159 
2160 	/*
2161 	 * Finish setting up the local APIC on the BSP once we know
2162 	 * how to properly program the LINT pins.  In particular, this
2163 	 * enables the EOI suppression mode, if LAPIC supports it and
2164 	 * user did not disable the mode.
2165 	 */
2166 	lapic_setup(1);
2167 	if (bootverbose)
2168 		lapic_dump("BSP");
2169 
2170 	/* Enable the MSI "pic". */
2171 	msi_init();
2172 
2173 #ifdef XENHVM
2174 	xen_intr_alloc_irqs();
2175 #endif
2176 }
2177 SYSINIT(apic_setup_io, SI_SUB_INTR, SI_ORDER_THIRD, apic_setup_io, NULL);
2178 
2179 #ifdef SMP
2180 /*
2181  * Inter Processor Interrupt functions.  The lapic_ipi_*() functions are
2182  * private to the MD code.  The public interface for the rest of the
2183  * kernel is defined in mp_machdep.c.
2184  */
2185 
2186 /*
2187  * Wait delay microseconds for IPI to be sent.  If delay is -1, we
2188  * wait forever.
2189  */
2190 int
lapic_ipi_wait(int delay)2191 lapic_ipi_wait(int delay)
2192 {
2193 	uint64_t rx;
2194 
2195 	/* LAPIC_ICR.APIC_DELSTAT_MASK is undefined in x2APIC mode */
2196 	if (x2apic_mode)
2197 		return (1);
2198 
2199 	for (rx = 0; delay == -1 || rx < lapic_ipi_wait_mult * delay; rx++) {
2200 		if ((lapic_read_icr_lo() & APIC_DELSTAT_MASK) ==
2201 		    APIC_DELSTAT_IDLE)
2202 			return (1);
2203 		ia32_pause();
2204 	}
2205 	return (0);
2206 }
2207 
2208 void
lapic_ipi_raw(register_t icrlo,u_int dest)2209 lapic_ipi_raw(register_t icrlo, u_int dest)
2210 {
2211 	uint32_t icrhi;
2212 
2213 	/* XXX: Need more sanity checking of icrlo? */
2214 	KASSERT(x2apic_mode || lapic_map != NULL,
2215 	    ("%s called too early", __func__));
2216 	KASSERT(x2apic_mode ||
2217 	    (dest & ~(APIC_ID_MASK >> APIC_ID_SHIFT)) == 0,
2218 	    ("%s: invalid dest field", __func__));
2219 	KASSERT((icrlo & APIC_ICRLO_RESV_MASK) == 0,
2220 	    ("%s: reserved bits set in ICR LO register", __func__));
2221 
2222 	if ((icrlo & APIC_DEST_MASK) == APIC_DEST_DESTFLD) {
2223 		if (x2apic_mode)
2224 			icrhi = dest;
2225 		else
2226 			icrhi = dest << APIC_ID_SHIFT;
2227 		lapic_write_icr(icrhi, icrlo);
2228 	} else {
2229 		lapic_write_icr_lo(icrlo);
2230 	}
2231 }
2232 
2233 #ifdef DETECT_DEADLOCK
2234 #define	AFTER_SPIN	50
2235 #endif
2236 
2237 static void
native_lapic_ipi_vectored(u_int vector,int dest)2238 native_lapic_ipi_vectored(u_int vector, int dest)
2239 {
2240 	register_t icrlo, destfield;
2241 
2242 	KASSERT((vector & ~APIC_VECTOR_MASK) == 0,
2243 	    ("%s: invalid vector %d", __func__, vector));
2244 
2245 	destfield = 0;
2246 	switch (dest) {
2247 	case APIC_IPI_DEST_SELF:
2248 		if (x2apic_mode && vector < IPI_NMI_FIRST) {
2249 			lapic_write_self_ipi(vector);
2250 			return;
2251 		}
2252 		icrlo = APIC_DEST_SELF;
2253 		break;
2254 	case APIC_IPI_DEST_ALL:
2255 		icrlo = APIC_DEST_ALLISELF;
2256 		break;
2257 	case APIC_IPI_DEST_OTHERS:
2258 		icrlo = APIC_DEST_ALLESELF;
2259 		break;
2260 	default:
2261 		icrlo = 0;
2262 		KASSERT(x2apic_mode ||
2263 		    (dest & ~(APIC_ID_MASK >> APIC_ID_SHIFT)) == 0,
2264 		    ("%s: invalid destination 0x%x", __func__, dest));
2265 		destfield = dest;
2266 	}
2267 
2268 	/*
2269 	 * NMI IPIs are just fake vectors used to send a NMI.  Use special rules
2270 	 * regarding NMIs if passed, otherwise specify the vector.
2271 	 */
2272 	if (vector >= IPI_NMI_FIRST)
2273 		icrlo |= APIC_DELMODE_NMI;
2274 	else
2275 		icrlo |= vector | APIC_DELMODE_FIXED;
2276 	icrlo |= APIC_DESTMODE_PHY | APIC_TRIGMOD_EDGE | APIC_LEVEL_ASSERT;
2277 
2278 	/* Wait for an earlier IPI to finish. */
2279 	if (!lapic_ipi_wait(lapic_ds_idle_timeout)) {
2280 		if (KERNEL_PANICKED())
2281 			return;
2282 		else
2283 			panic("APIC: Previous IPI is stuck");
2284 	}
2285 
2286 	lapic_ipi_raw(icrlo, destfield);
2287 
2288 #ifdef DETECT_DEADLOCK
2289 	/* Wait for IPI to be delivered. */
2290 	if (!lapic_ipi_wait(AFTER_SPIN)) {
2291 #ifdef needsattention
2292 		/*
2293 		 * XXX FIXME:
2294 		 *
2295 		 * The above function waits for the message to actually be
2296 		 * delivered.  It breaks out after an arbitrary timeout
2297 		 * since the message should eventually be delivered (at
2298 		 * least in theory) and that if it wasn't we would catch
2299 		 * the failure with the check above when the next IPI is
2300 		 * sent.
2301 		 *
2302 		 * We could skip this wait entirely, EXCEPT it probably
2303 		 * protects us from other routines that assume that the
2304 		 * message was delivered and acted upon when this function
2305 		 * returns.
2306 		 */
2307 		printf("APIC: IPI might be stuck\n");
2308 #else /* !needsattention */
2309 		/* Wait until mesage is sent without a timeout. */
2310 		while (lapic_read_icr_lo() & APIC_DELSTAT_PEND)
2311 			ia32_pause();
2312 #endif /* needsattention */
2313 	}
2314 #endif /* DETECT_DEADLOCK */
2315 }
2316 
2317 void (*ipi_vectored)(u_int, int) = &native_lapic_ipi_vectored;
2318 #endif /* SMP */
2319 
2320 /*
2321  * Since the IDT is shared by all CPUs the IPI slot update needs to be globally
2322  * visible.
2323  *
2324  * Consider the case where an IPI is generated immediately after allocation:
2325  *     vector = lapic_ipi_alloc(ipifunc);
2326  *     ipi_selected(other_cpus, vector);
2327  *
2328  * In xAPIC mode a write to ICR_LO has serializing semantics because the
2329  * APIC page is mapped as an uncached region. In x2APIC mode there is an
2330  * explicit 'mfence' before the ICR MSR is written. Therefore in both cases
2331  * the IDT slot update is globally visible before the IPI is delivered.
2332  */
2333 int
lapic_ipi_alloc(inthand_t * ipifunc)2334 lapic_ipi_alloc(inthand_t *ipifunc)
2335 {
2336 	struct gate_descriptor *ip;
2337 	long func;
2338 	int idx, vector;
2339 
2340 	KASSERT(ipifunc != &IDTVEC(rsvd) && ipifunc != &IDTVEC(rsvd_pti),
2341 	    ("invalid ipifunc %p", ipifunc));
2342 
2343 	vector = -1;
2344 	mtx_lock_spin(&icu_lock);
2345 	for (idx = IPI_DYN_FIRST; idx <= IPI_DYN_LAST; idx++) {
2346 		ip = &idt[idx];
2347 		func = (ip->gd_hioffset << 16) | ip->gd_looffset;
2348 #ifdef __i386__
2349 		func -= setidt_disp;
2350 #endif
2351 		if ((!pti && func == (uintptr_t)&IDTVEC(rsvd)) ||
2352 		    (pti && func == (uintptr_t)&IDTVEC(rsvd_pti))) {
2353 			vector = idx;
2354 			setidt(vector, ipifunc, SDT_APIC, SEL_KPL, GSEL_APIC);
2355 			break;
2356 		}
2357 	}
2358 	mtx_unlock_spin(&icu_lock);
2359 	return (vector);
2360 }
2361 
2362 void
lapic_ipi_free(int vector)2363 lapic_ipi_free(int vector)
2364 {
2365 	struct gate_descriptor *ip;
2366 	long func __diagused;
2367 
2368 	KASSERT(vector >= IPI_DYN_FIRST && vector <= IPI_DYN_LAST,
2369 	    ("%s: invalid vector %d", __func__, vector));
2370 
2371 	mtx_lock_spin(&icu_lock);
2372 	ip = &idt[vector];
2373 	func = (ip->gd_hioffset << 16) | ip->gd_looffset;
2374 #ifdef __i386__
2375 	func -= setidt_disp;
2376 #endif
2377 	KASSERT(func != (uintptr_t)&IDTVEC(rsvd) &&
2378 	    func != (uintptr_t)&IDTVEC(rsvd_pti),
2379 	    ("invalid idtfunc %#lx", func));
2380 	setidt(vector, pti ? &IDTVEC(rsvd_pti) : &IDTVEC(rsvd), SDT_APIC,
2381 	    SEL_KPL, GSEL_APIC);
2382 	mtx_unlock_spin(&icu_lock);
2383 }
2384