xref: /freebsd/sys/dev/cpuctl/cpuctl.c (revision fdafd315ad0d0f28a11b9fb4476a9ab059c62b92)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2006-2008 Stanislav Sedov <stas@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  */
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/conf.h>
33 #include <sys/fcntl.h>
34 #include <sys/ioccom.h>
35 #include <sys/malloc.h>
36 #include <sys/module.h>
37 #include <sys/mutex.h>
38 #include <sys/priv.h>
39 #include <sys/proc.h>
40 #include <sys/queue.h>
41 #include <sys/sched.h>
42 #include <sys/kernel.h>
43 #include <sys/sysctl.h>
44 #include <sys/uio.h>
45 #include <sys/pcpu.h>
46 #include <sys/smp.h>
47 #include <sys/pmckern.h>
48 #include <sys/cpuctl.h>
49 
50 #include <vm/vm.h>
51 #include <vm/vm_param.h>
52 #include <vm/pmap.h>
53 
54 #include <machine/cpufunc.h>
55 #include <machine/md_var.h>
56 #include <machine/specialreg.h>
57 #include <x86/ucode.h>
58 
59 static d_open_t cpuctl_open;
60 static d_ioctl_t cpuctl_ioctl;
61 
62 #define	CPUCTL_VERSION 1
63 
64 #ifdef CPUCTL_DEBUG
65 # define	DPRINTF(format,...) printf(format, __VA_ARGS__);
66 #else
67 # define	DPRINTF(...)
68 #endif
69 
70 #define	UCODE_SIZE_MAX	(4 * 1024 * 1024)
71 
72 static int cpuctl_do_msr(int cpu, cpuctl_msr_args_t *data, u_long cmd,
73     struct thread *td);
74 static int cpuctl_do_cpuid(int cpu, cpuctl_cpuid_args_t *data,
75     struct thread *td);
76 static int cpuctl_do_cpuid_count(int cpu, cpuctl_cpuid_count_args_t *data,
77     struct thread *td);
78 static int cpuctl_do_eval_cpu_features(int cpu, struct thread *td);
79 static int cpuctl_do_update(int cpu, cpuctl_update_args_t *data,
80     struct thread *td);
81 static int update_intel(int cpu, cpuctl_update_args_t *args,
82     struct thread *td);
83 static int update_amd(int cpu, cpuctl_update_args_t *args, struct thread *td);
84 static int update_via(int cpu, cpuctl_update_args_t *args,
85     struct thread *td);
86 
87 static struct cdev **cpuctl_devs;
88 static MALLOC_DEFINE(M_CPUCTL, "cpuctl", "CPUCTL buffer");
89 
90 static struct cdevsw cpuctl_cdevsw = {
91         .d_version =    D_VERSION,
92         .d_open =       cpuctl_open,
93         .d_ioctl =      cpuctl_ioctl,
94         .d_name =       "cpuctl",
95 };
96 
97 /*
98  * This function checks if specified cpu enabled or not.
99  */
100 static int
cpu_enabled(int cpu)101 cpu_enabled(int cpu)
102 {
103 
104 	return (pmc_cpu_is_disabled(cpu) == 0);
105 }
106 
107 /*
108  * Check if the current thread is bound to a specific cpu.
109  */
110 static int
cpu_sched_is_bound(struct thread * td)111 cpu_sched_is_bound(struct thread *td)
112 {
113 	int ret;
114 
115 	thread_lock(td);
116 	ret = sched_is_bound(td);
117 	thread_unlock(td);
118 	return (ret);
119 }
120 
121 /*
122  * Switch to target cpu to run.
123  */
124 static void
set_cpu(int cpu,struct thread * td)125 set_cpu(int cpu, struct thread *td)
126 {
127 
128 	KASSERT(cpu >= 0 && cpu <= mp_maxid && cpu_enabled(cpu),
129 	    ("[cpuctl,%d]: bad cpu number %d", __LINE__, cpu));
130 	thread_lock(td);
131 	sched_bind(td, cpu);
132 	thread_unlock(td);
133 	KASSERT(td->td_oncpu == cpu,
134 	    ("[cpuctl,%d]: cannot bind to target cpu %d on cpu %d", __LINE__,
135 	    cpu, td->td_oncpu));
136 }
137 
138 static void
restore_cpu(int oldcpu,int is_bound,struct thread * td)139 restore_cpu(int oldcpu, int is_bound, struct thread *td)
140 {
141 
142 	KASSERT(oldcpu >= 0 && oldcpu <= mp_maxid && cpu_enabled(oldcpu),
143 	    ("[cpuctl,%d]: bad cpu number %d", __LINE__, oldcpu));
144 	thread_lock(td);
145 	if (is_bound == 0)
146 		sched_unbind(td);
147 	else
148 		sched_bind(td, oldcpu);
149 	thread_unlock(td);
150 }
151 
152 int
cpuctl_ioctl(struct cdev * dev,u_long cmd,caddr_t data,int flags,struct thread * td)153 cpuctl_ioctl(struct cdev *dev, u_long cmd, caddr_t data,
154     int flags, struct thread *td)
155 {
156 	int cpu, ret;
157 
158 	cpu = dev2unit(dev);
159 	if (cpu > mp_maxid || !cpu_enabled(cpu)) {
160 		DPRINTF("[cpuctl,%d]: bad cpu number %d\n", __LINE__, cpu);
161 		return (ENXIO);
162 	}
163 	/* Require write flag for "write" requests. */
164 	if ((cmd == CPUCTL_MSRCBIT || cmd == CPUCTL_MSRSBIT ||
165 	    cmd == CPUCTL_UPDATE || cmd == CPUCTL_WRMSR ||
166 	    cmd == CPUCTL_EVAL_CPU_FEATURES) &&
167 	    (flags & FWRITE) == 0)
168 		return (EPERM);
169 	switch (cmd) {
170 	case CPUCTL_RDMSR:
171 		ret = cpuctl_do_msr(cpu, (cpuctl_msr_args_t *)data, cmd, td);
172 		break;
173 	case CPUCTL_MSRSBIT:
174 	case CPUCTL_MSRCBIT:
175 	case CPUCTL_WRMSR:
176 		ret = priv_check(td, PRIV_CPUCTL_WRMSR);
177 		if (ret != 0)
178 			goto fail;
179 		ret = cpuctl_do_msr(cpu, (cpuctl_msr_args_t *)data, cmd, td);
180 		break;
181 	case CPUCTL_CPUID:
182 		ret = cpuctl_do_cpuid(cpu, (cpuctl_cpuid_args_t *)data, td);
183 		break;
184 	case CPUCTL_UPDATE:
185 		ret = priv_check(td, PRIV_CPUCTL_UPDATE);
186 		if (ret != 0)
187 			goto fail;
188 		ret = cpuctl_do_update(cpu, (cpuctl_update_args_t *)data, td);
189 		break;
190 	case CPUCTL_CPUID_COUNT:
191 		ret = cpuctl_do_cpuid_count(cpu,
192 		    (cpuctl_cpuid_count_args_t *)data, td);
193 		break;
194 	case CPUCTL_EVAL_CPU_FEATURES:
195 		ret = cpuctl_do_eval_cpu_features(cpu, td);
196 		break;
197 	default:
198 		ret = EINVAL;
199 		break;
200 	}
201 fail:
202 	return (ret);
203 }
204 
205 /*
206  * Actually perform cpuid operation.
207  */
208 static int
cpuctl_do_cpuid_count(int cpu,cpuctl_cpuid_count_args_t * data,struct thread * td)209 cpuctl_do_cpuid_count(int cpu, cpuctl_cpuid_count_args_t *data,
210     struct thread *td)
211 {
212 	int is_bound = 0;
213 	int oldcpu;
214 
215 	KASSERT(cpu >= 0 && cpu <= mp_maxid,
216 	    ("[cpuctl,%d]: bad cpu number %d", __LINE__, cpu));
217 
218 	/* Explicitly clear cpuid data to avoid returning stale info. */
219 	bzero(data->data, sizeof(data->data));
220 	DPRINTF("[cpuctl,%d]: retrieving cpuid lev %#0x type %#0x for %d cpu\n",
221 	    __LINE__, data->level, data->level_type, cpu);
222 #ifdef __i386__
223 	if (cpu_id == 0)
224 		return (ENODEV);
225 #endif
226 	oldcpu = td->td_oncpu;
227 	is_bound = cpu_sched_is_bound(td);
228 	set_cpu(cpu, td);
229 	cpuid_count(data->level, data->level_type, data->data);
230 	restore_cpu(oldcpu, is_bound, td);
231 	return (0);
232 }
233 
234 static int
cpuctl_do_cpuid(int cpu,cpuctl_cpuid_args_t * data,struct thread * td)235 cpuctl_do_cpuid(int cpu, cpuctl_cpuid_args_t *data, struct thread *td)
236 {
237 	cpuctl_cpuid_count_args_t cdata;
238 	int error;
239 
240 	cdata.level = data->level;
241 	/* Override the level type. */
242 	cdata.level_type = 0;
243 	error = cpuctl_do_cpuid_count(cpu, &cdata, td);
244 	bcopy(cdata.data, data->data, sizeof(data->data)); /* Ignore error */
245 	return (error);
246 }
247 
248 /*
249  * Actually perform MSR operations.
250  */
251 static int
cpuctl_do_msr(int cpu,cpuctl_msr_args_t * data,u_long cmd,struct thread * td)252 cpuctl_do_msr(int cpu, cpuctl_msr_args_t *data, u_long cmd, struct thread *td)
253 {
254 	uint64_t reg;
255 	int is_bound = 0;
256 	int oldcpu;
257 	int ret;
258 
259 	KASSERT(cpu >= 0 && cpu <= mp_maxid,
260 	    ("[cpuctl,%d]: bad cpu number %d", __LINE__, cpu));
261 
262 	/*
263 	 * Explicitly clear cpuid data to avoid returning stale
264 	 * info
265 	 */
266 	DPRINTF("[cpuctl,%d]: operating on MSR %#0x for %d cpu\n", __LINE__,
267 	    data->msr, cpu);
268 #ifdef __i386__
269 	if ((cpu_feature & CPUID_MSR) == 0)
270 		return (ENODEV);
271 #endif
272 	oldcpu = td->td_oncpu;
273 	is_bound = cpu_sched_is_bound(td);
274 	set_cpu(cpu, td);
275 	if (cmd == CPUCTL_RDMSR) {
276 		data->data = 0;
277 		ret = rdmsr_safe(data->msr, &data->data);
278 	} else if (cmd == CPUCTL_WRMSR) {
279 		ret = wrmsr_safe(data->msr, data->data);
280 	} else if (cmd == CPUCTL_MSRSBIT) {
281 		critical_enter();
282 		ret = rdmsr_safe(data->msr, &reg);
283 		if (ret == 0)
284 			ret = wrmsr_safe(data->msr, reg | data->data);
285 		critical_exit();
286 	} else if (cmd == CPUCTL_MSRCBIT) {
287 		critical_enter();
288 		ret = rdmsr_safe(data->msr, &reg);
289 		if (ret == 0)
290 			ret = wrmsr_safe(data->msr, reg & ~data->data);
291 		critical_exit();
292 	} else
293 		panic("[cpuctl,%d]: unknown operation requested: %lu",
294 		    __LINE__, cmd);
295 	restore_cpu(oldcpu, is_bound, td);
296 	return (ret);
297 }
298 
299 /*
300  * Actually perform microcode update.
301  */
302 static int
cpuctl_do_update(int cpu,cpuctl_update_args_t * data,struct thread * td)303 cpuctl_do_update(int cpu, cpuctl_update_args_t *data, struct thread *td)
304 {
305 	cpuctl_cpuid_args_t args = {
306 		.level = 0,
307 	};
308 	char vendor[13];
309 	int ret;
310 
311 	KASSERT(cpu >= 0 && cpu <= mp_maxid,
312 	    ("[cpuctl,%d]: bad cpu number %d", __LINE__, cpu));
313 	DPRINTF("[cpuctl,%d]: XXX %d", __LINE__, cpu);
314 
315 	ret = cpuctl_do_cpuid(cpu, &args, td);
316 	if (ret != 0)
317 		return (ret);
318 	((uint32_t *)vendor)[0] = args.data[1];
319 	((uint32_t *)vendor)[1] = args.data[3];
320 	((uint32_t *)vendor)[2] = args.data[2];
321 	vendor[12] = '\0';
322 	if (strncmp(vendor, INTEL_VENDOR_ID, sizeof(INTEL_VENDOR_ID)) == 0)
323 		ret = update_intel(cpu, data, td);
324 	else if(strncmp(vendor, AMD_VENDOR_ID, sizeof(AMD_VENDOR_ID)) == 0)
325 		ret = update_amd(cpu, data, td);
326 	else if(strncmp(vendor, CENTAUR_VENDOR_ID, sizeof(CENTAUR_VENDOR_ID))
327 	    == 0)
328 		ret = update_via(cpu, data, td);
329 	else
330 		ret = ENXIO;
331 	return (ret);
332 }
333 
334 struct ucode_update_data {
335 	void *ptr;
336 	int cpu;
337 	int ret;
338 };
339 
340 static void
ucode_intel_load_rv(void * arg)341 ucode_intel_load_rv(void *arg)
342 {
343 	struct ucode_update_data *d;
344 
345 	d = arg;
346 	if (PCPU_GET(cpuid) == d->cpu)
347 		d->ret = ucode_intel_load(d->ptr, true, NULL, NULL);
348 }
349 
350 static int
update_intel(int cpu,cpuctl_update_args_t * args,struct thread * td)351 update_intel(int cpu, cpuctl_update_args_t *args, struct thread *td)
352 {
353 	struct ucode_update_data d;
354 	void *ptr;
355 	int is_bound, oldcpu, ret;
356 
357 	if (args->size == 0 || args->data == NULL) {
358 		DPRINTF("[cpuctl,%d]: zero-sized firmware image", __LINE__);
359 		return (EINVAL);
360 	}
361 	if (args->size > UCODE_SIZE_MAX) {
362 		DPRINTF("[cpuctl,%d]: firmware image too large", __LINE__);
363 		return (EINVAL);
364 	}
365 
366 	/*
367 	 * 16 byte alignment required.  Rely on the fact that
368 	 * malloc(9) always returns the pointer aligned at least on
369 	 * the size of the allocation.
370 	 */
371 	ptr = malloc(args->size + 16, M_CPUCTL, M_WAITOK);
372 	if (copyin(args->data, ptr, args->size) != 0) {
373 		DPRINTF("[cpuctl,%d]: copyin %p->%p of %zd bytes failed",
374 		    __LINE__, args->data, ptr, args->size);
375 		ret = EFAULT;
376 		goto out;
377 	}
378 	oldcpu = td->td_oncpu;
379 	is_bound = cpu_sched_is_bound(td);
380 	set_cpu(cpu, td);
381 	d.ptr = ptr;
382 	d.cpu = cpu;
383 	smp_rendezvous(NULL, ucode_intel_load_rv, NULL, &d);
384 	restore_cpu(oldcpu, is_bound, td);
385 	ret = d.ret;
386 
387 	/*
388 	 * Replace any existing update.  This ensures that the new update
389 	 * will be reloaded automatically during ACPI resume.
390 	 */
391 	if (ret == 0)
392 		ptr = ucode_update(ptr);
393 
394 out:
395 	free(ptr, M_CPUCTL);
396 	return (ret);
397 }
398 
399 /*
400  * NB: MSR 0xc0010020, MSR_K8_UCODE_UPDATE, is not documented by AMD.
401  * Coreboot, illumos and Linux source code was used to understand
402  * its workings.
403  */
404 static void
amd_ucode_wrmsr(void * ucode_ptr)405 amd_ucode_wrmsr(void *ucode_ptr)
406 {
407 	uint32_t tmp[4];
408 
409 	wrmsr_safe(MSR_K8_UCODE_UPDATE, (uintptr_t)ucode_ptr);
410 	do_cpuid(0, tmp);
411 }
412 
413 static int
update_amd(int cpu,cpuctl_update_args_t * args,struct thread * td)414 update_amd(int cpu, cpuctl_update_args_t *args, struct thread *td)
415 {
416 	void *ptr;
417 	int ret;
418 
419 	if (args->size == 0 || args->data == NULL) {
420 		DPRINTF("[cpuctl,%d]: zero-sized firmware image", __LINE__);
421 		return (EINVAL);
422 	}
423 	if (args->size > UCODE_SIZE_MAX) {
424 		DPRINTF("[cpuctl,%d]: firmware image too large", __LINE__);
425 		return (EINVAL);
426 	}
427 
428 	/*
429 	 * 16 byte alignment required.  Rely on the fact that
430 	 * malloc(9) always returns the pointer aligned at least on
431 	 * the size of the allocation.
432 	 */
433 	ptr = malloc(args->size + 16, M_CPUCTL, M_ZERO | M_WAITOK);
434 	if (copyin(args->data, ptr, args->size) != 0) {
435 		DPRINTF("[cpuctl,%d]: copyin %p->%p of %zd bytes failed",
436 		    __LINE__, args->data, ptr, args->size);
437 		ret = EFAULT;
438 		goto fail;
439 	}
440 	smp_rendezvous(NULL, amd_ucode_wrmsr, NULL, ptr);
441 	ret = 0;
442 fail:
443 	free(ptr, M_CPUCTL);
444 	return (ret);
445 }
446 
447 static int
update_via(int cpu,cpuctl_update_args_t * args,struct thread * td)448 update_via(int cpu, cpuctl_update_args_t *args, struct thread *td)
449 {
450 	void *ptr;
451 	uint64_t rev0, rev1, res;
452 	uint32_t tmp[4];
453 	int is_bound;
454 	int oldcpu;
455 	int ret;
456 
457 	if (args->size == 0 || args->data == NULL) {
458 		DPRINTF("[cpuctl,%d]: zero-sized firmware image", __LINE__);
459 		return (EINVAL);
460 	}
461 	if (args->size > UCODE_SIZE_MAX) {
462 		DPRINTF("[cpuctl,%d]: firmware image too large", __LINE__);
463 		return (EINVAL);
464 	}
465 
466 	/*
467 	 * 4 byte alignment required.
468 	 */
469 	ptr = malloc(args->size, M_CPUCTL, M_WAITOK);
470 	if (copyin(args->data, ptr, args->size) != 0) {
471 		DPRINTF("[cpuctl,%d]: copyin %p->%p of %zd bytes failed",
472 		    __LINE__, args->data, ptr, args->size);
473 		ret = EFAULT;
474 		goto fail;
475 	}
476 	oldcpu = td->td_oncpu;
477 	is_bound = cpu_sched_is_bound(td);
478 	set_cpu(cpu, td);
479 	critical_enter();
480 	rdmsr_safe(MSR_BIOS_SIGN, &rev0); /* Get current microcode revision. */
481 
482 	/*
483 	 * Perform update.
484 	 */
485 	wrmsr_safe(MSR_BIOS_UPDT_TRIG, (uintptr_t)(ptr));
486 	do_cpuid(1, tmp);
487 
488 	/*
489 	 * Result are in low byte of MSR FCR5:
490 	 * 0x00: No update has been attempted since RESET.
491 	 * 0x01: The last attempted update was successful.
492 	 * 0x02: The last attempted update was unsuccessful due to a bad
493 	 *       environment. No update was loaded and any preexisting
494 	 *       patches are still active.
495 	 * 0x03: The last attempted update was not applicable to this processor.
496 	 *       No update was loaded and any preexisting patches are still
497 	 *       active.
498 	 * 0x04: The last attempted update was not successful due to an invalid
499 	 *       update data block. No update was loaded and any preexisting
500 	 *       patches are still active
501 	 */
502 	rdmsr_safe(0x1205, &res);
503 	res &= 0xff;
504 	critical_exit();
505 	rdmsr_safe(MSR_BIOS_SIGN, &rev1); /* Get new microcode revision. */
506 	restore_cpu(oldcpu, is_bound, td);
507 
508 	DPRINTF("[cpu,%d]: rev0=%x rev1=%x res=%x\n", __LINE__,
509 	    (unsigned)(rev0 >> 32), (unsigned)(rev1 >> 32), (unsigned)res);
510 
511 	if (res != 0x01)
512 		ret = EINVAL;
513 	else
514 		ret = 0;
515 fail:
516 	free(ptr, M_CPUCTL);
517 	return (ret);
518 }
519 
520 static int
cpuctl_do_eval_cpu_features(int cpu,struct thread * td)521 cpuctl_do_eval_cpu_features(int cpu, struct thread *td)
522 {
523 	int is_bound = 0;
524 	int oldcpu;
525 
526 	KASSERT(cpu >= 0 && cpu <= mp_maxid,
527 	    ("[cpuctl,%d]: bad cpu number %d", __LINE__, cpu));
528 
529 #ifdef __i386__
530 	if (cpu_id == 0)
531 		return (ENODEV);
532 #endif
533 	oldcpu = td->td_oncpu;
534 	is_bound = cpu_sched_is_bound(td);
535 	set_cpu(cpu, td);
536 	identify_cpu1();
537 	identify_cpu2();
538 	restore_cpu(oldcpu, is_bound, td);
539 	hw_ibrs_recalculate(true);
540 	hw_ssb_recalculate(true);
541 #ifdef __amd64__
542 	amd64_syscall_ret_flush_l1d_recalc();
543 	pmap_allow_2m_x_ept_recalculate();
544 #endif
545 	hw_mds_recalculate();
546 	x86_taa_recalculate();
547 	x86_rngds_mitg_recalculate(true);
548 	zenbleed_check_and_apply(true);
549 	printcpuinfo();
550 	return (0);
551 }
552 
553 int
cpuctl_open(struct cdev * dev,int flags,int fmt __unused,struct thread * td)554 cpuctl_open(struct cdev *dev, int flags, int fmt __unused, struct thread *td)
555 {
556 	int ret = 0;
557 	int cpu;
558 
559 	cpu = dev2unit(dev);
560 	if (cpu > mp_maxid || !cpu_enabled(cpu)) {
561 		DPRINTF("[cpuctl,%d]: incorrect cpu number %d\n", __LINE__,
562 		    cpu);
563 		return (ENXIO);
564 	}
565 	if (flags & FWRITE)
566 		ret = securelevel_gt(td->td_ucred, 0);
567 	return (ret);
568 }
569 
570 static int
cpuctl_modevent(module_t mod __unused,int type,void * data __unused)571 cpuctl_modevent(module_t mod __unused, int type, void *data __unused)
572 {
573 	int cpu;
574 
575 	switch(type) {
576 	case MOD_LOAD:
577 		if (bootverbose)
578 			printf("cpuctl: access to MSR registers/cpuid info.\n");
579 		cpuctl_devs = malloc(sizeof(*cpuctl_devs) * (mp_maxid + 1), M_CPUCTL,
580 		    M_WAITOK | M_ZERO);
581 		CPU_FOREACH(cpu)
582 			if (cpu_enabled(cpu))
583 				cpuctl_devs[cpu] = make_dev(&cpuctl_cdevsw, cpu,
584 				    UID_ROOT, GID_KMEM, 0640, "cpuctl%d", cpu);
585 		break;
586 	case MOD_UNLOAD:
587 		CPU_FOREACH(cpu) {
588 			if (cpuctl_devs[cpu] != NULL)
589 				destroy_dev(cpuctl_devs[cpu]);
590 		}
591 		free(cpuctl_devs, M_CPUCTL);
592 		break;
593 	case MOD_SHUTDOWN:
594 		break;
595 	default:
596 		return (EOPNOTSUPP);
597         }
598 	return (0);
599 }
600 
601 DEV_MODULE(cpuctl, cpuctl_modevent, NULL);
602 MODULE_VERSION(cpuctl, CPUCTL_VERSION);
603