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