1 /*
2  *  (c) 2005, 2006 Advanced Micro Devices, Inc.
3  *  Your use of this code is subject to the terms and conditions of the
4  *  GNU general public license version 2. See "COPYING" or
5  *  http://www.gnu.org/licenses/gpl.html
6  *
7  *  Written by Jacob Shin - AMD, Inc.
8  *
9  *  Support : jacob.shin@amd.com
10  *
11  *  April 2006
12  *     - added support for AMD Family 0x10 processors
13  *
14  *  All MC4_MISCi registers are shared between multi-cores
15  */
16 #include <linux/interrupt.h>
17 #include <linux/notifier.h>
18 #include <linux/kobject.h>
19 #include <linux/percpu.h>
20 #include <linux/errno.h>
21 #include <linux/sched.h>
22 #include <linux/sysfs.h>
23 #include <linux/slab.h>
24 #include <linux/init.h>
25 #include <linux/cpu.h>
26 #include <linux/smp.h>
27 
28 #include <asm/apic.h>
29 #include <asm/idle.h>
30 #include <asm/mce.h>
31 #include <asm/msr.h>
32 
33 #define NR_BANKS          6
34 #define NR_BLOCKS         9
35 #define THRESHOLD_MAX     0xFFF
36 #define INT_TYPE_APIC     0x00020000
37 #define MASK_VALID_HI     0x80000000
38 #define MASK_CNTP_HI      0x40000000
39 #define MASK_LOCKED_HI    0x20000000
40 #define MASK_LVTOFF_HI    0x00F00000
41 #define MASK_COUNT_EN_HI  0x00080000
42 #define MASK_INT_TYPE_HI  0x00060000
43 #define MASK_OVERFLOW_HI  0x00010000
44 #define MASK_ERR_COUNT_HI 0x00000FFF
45 #define MASK_BLKPTR_LO    0xFF000000
46 #define MCG_XBLK_ADDR     0xC0000400
47 
48 struct threshold_block {
49 	unsigned int		block;
50 	unsigned int		bank;
51 	unsigned int		cpu;
52 	u32			address;
53 	u16			interrupt_enable;
54 	u16			threshold_limit;
55 	struct kobject		kobj;
56 	struct list_head	miscj;
57 };
58 
59 struct threshold_bank {
60 	struct kobject		*kobj;
61 	struct threshold_block	*blocks;
62 	cpumask_var_t		cpus;
63 };
64 static DEFINE_PER_CPU(struct threshold_bank * [NR_BANKS], threshold_banks);
65 
66 static unsigned char shared_bank[NR_BANKS] = {
67 	0, 0, 0, 0, 1
68 };
69 
70 static DEFINE_PER_CPU(unsigned char, bank_map);	/* see which banks are on */
71 
72 static void amd_threshold_interrupt(void);
73 
74 /*
75  * CPU Initialization
76  */
77 
78 struct thresh_restart {
79 	struct threshold_block	*b;
80 	int			reset;
81 	int			set_lvt_off;
82 	int			lvt_off;
83 	u16			old_limit;
84 };
85 
lvt_off_valid(struct threshold_block * b,int apic,u32 lo,u32 hi)86 static int lvt_off_valid(struct threshold_block *b, int apic, u32 lo, u32 hi)
87 {
88 	int msr = (hi & MASK_LVTOFF_HI) >> 20;
89 
90 	if (apic < 0) {
91 		pr_err(FW_BUG "cpu %d, failed to setup threshold interrupt "
92 		       "for bank %d, block %d (MSR%08X=0x%x%08x)\n", b->cpu,
93 		       b->bank, b->block, b->address, hi, lo);
94 		return 0;
95 	}
96 
97 	if (apic != msr) {
98 		pr_err(FW_BUG "cpu %d, invalid threshold interrupt offset %d "
99 		       "for bank %d, block %d (MSR%08X=0x%x%08x)\n",
100 		       b->cpu, apic, b->bank, b->block, b->address, hi, lo);
101 		return 0;
102 	}
103 
104 	return 1;
105 };
106 
107 /* must be called with correct cpu affinity */
108 /* Called via smp_call_function_single() */
threshold_restart_bank(void * _tr)109 static void threshold_restart_bank(void *_tr)
110 {
111 	struct thresh_restart *tr = _tr;
112 	u32 hi, lo;
113 
114 	rdmsr(tr->b->address, lo, hi);
115 
116 	if (tr->b->threshold_limit < (hi & THRESHOLD_MAX))
117 		tr->reset = 1;	/* limit cannot be lower than err count */
118 
119 	if (tr->reset) {		/* reset err count and overflow bit */
120 		hi =
121 		    (hi & ~(MASK_ERR_COUNT_HI | MASK_OVERFLOW_HI)) |
122 		    (THRESHOLD_MAX - tr->b->threshold_limit);
123 	} else if (tr->old_limit) {	/* change limit w/o reset */
124 		int new_count = (hi & THRESHOLD_MAX) +
125 		    (tr->old_limit - tr->b->threshold_limit);
126 
127 		hi = (hi & ~MASK_ERR_COUNT_HI) |
128 		    (new_count & THRESHOLD_MAX);
129 	}
130 
131 	if (tr->set_lvt_off) {
132 		if (lvt_off_valid(tr->b, tr->lvt_off, lo, hi)) {
133 			/* set new lvt offset */
134 			hi &= ~MASK_LVTOFF_HI;
135 			hi |= tr->lvt_off << 20;
136 		}
137 	}
138 
139 	tr->b->interrupt_enable ?
140 	    (hi = (hi & ~MASK_INT_TYPE_HI) | INT_TYPE_APIC) :
141 	    (hi &= ~MASK_INT_TYPE_HI);
142 
143 	hi |= MASK_COUNT_EN_HI;
144 	wrmsr(tr->b->address, lo, hi);
145 }
146 
mce_threshold_block_init(struct threshold_block * b,int offset)147 static void mce_threshold_block_init(struct threshold_block *b, int offset)
148 {
149 	struct thresh_restart tr = {
150 		.b			= b,
151 		.set_lvt_off		= 1,
152 		.lvt_off		= offset,
153 	};
154 
155 	b->threshold_limit		= THRESHOLD_MAX;
156 	threshold_restart_bank(&tr);
157 };
158 
setup_APIC_mce(int reserved,int new)159 static int setup_APIC_mce(int reserved, int new)
160 {
161 	if (reserved < 0 && !setup_APIC_eilvt(new, THRESHOLD_APIC_VECTOR,
162 					      APIC_EILVT_MSG_FIX, 0))
163 		return new;
164 
165 	return reserved;
166 }
167 
168 /* cpu init entry point, called from mce.c with preempt off */
mce_amd_feature_init(struct cpuinfo_x86 * c)169 void mce_amd_feature_init(struct cpuinfo_x86 *c)
170 {
171 	struct threshold_block b;
172 	unsigned int cpu = smp_processor_id();
173 	u32 low = 0, high = 0, address = 0;
174 	unsigned int bank, block;
175 	int offset = -1;
176 
177 	for (bank = 0; bank < NR_BANKS; ++bank) {
178 		for (block = 0; block < NR_BLOCKS; ++block) {
179 			if (block == 0)
180 				address = MSR_IA32_MC0_MISC + bank * 4;
181 			else if (block == 1) {
182 				address = (low & MASK_BLKPTR_LO) >> 21;
183 				if (!address)
184 					break;
185 
186 				address += MCG_XBLK_ADDR;
187 			} else
188 				++address;
189 
190 			if (rdmsr_safe(address, &low, &high))
191 				break;
192 
193 			if (!(high & MASK_VALID_HI))
194 				continue;
195 
196 			if (!(high & MASK_CNTP_HI)  ||
197 			     (high & MASK_LOCKED_HI))
198 				continue;
199 
200 			if (!block)
201 				per_cpu(bank_map, cpu) |= (1 << bank);
202 			if (shared_bank[bank] && c->cpu_core_id)
203 				break;
204 
205 			offset = setup_APIC_mce(offset,
206 						(high & MASK_LVTOFF_HI) >> 20);
207 
208 			memset(&b, 0, sizeof(b));
209 			b.cpu		= cpu;
210 			b.bank		= bank;
211 			b.block		= block;
212 			b.address	= address;
213 
214 			mce_threshold_block_init(&b, offset);
215 			mce_threshold_vector = amd_threshold_interrupt;
216 		}
217 	}
218 }
219 
220 /*
221  * APIC Interrupt Handler
222  */
223 
224 /*
225  * threshold interrupt handler will service THRESHOLD_APIC_VECTOR.
226  * the interrupt goes off when error_count reaches threshold_limit.
227  * the handler will simply log mcelog w/ software defined bank number.
228  */
amd_threshold_interrupt(void)229 static void amd_threshold_interrupt(void)
230 {
231 	u32 low = 0, high = 0, address = 0;
232 	unsigned int bank, block;
233 	struct mce m;
234 
235 	mce_setup(&m);
236 
237 	/* assume first bank caused it */
238 	for (bank = 0; bank < NR_BANKS; ++bank) {
239 		if (!(per_cpu(bank_map, m.cpu) & (1 << bank)))
240 			continue;
241 		for (block = 0; block < NR_BLOCKS; ++block) {
242 			if (block == 0) {
243 				address = MSR_IA32_MC0_MISC + bank * 4;
244 			} else if (block == 1) {
245 				address = (low & MASK_BLKPTR_LO) >> 21;
246 				if (!address)
247 					break;
248 				address += MCG_XBLK_ADDR;
249 			} else {
250 				++address;
251 			}
252 
253 			if (rdmsr_safe(address, &low, &high))
254 				break;
255 
256 			if (!(high & MASK_VALID_HI)) {
257 				if (block)
258 					continue;
259 				else
260 					break;
261 			}
262 
263 			if (!(high & MASK_CNTP_HI)  ||
264 			     (high & MASK_LOCKED_HI))
265 				continue;
266 
267 			/*
268 			 * Log the machine check that caused the threshold
269 			 * event.
270 			 */
271 			machine_check_poll(MCP_TIMESTAMP,
272 					&__get_cpu_var(mce_poll_banks));
273 
274 			if (high & MASK_OVERFLOW_HI) {
275 				rdmsrl(address, m.misc);
276 				rdmsrl(MSR_IA32_MC0_STATUS + bank * 4,
277 				       m.status);
278 				m.bank = K8_MCE_THRESHOLD_BASE
279 				       + bank * NR_BLOCKS
280 				       + block;
281 				mce_log(&m);
282 				return;
283 			}
284 		}
285 	}
286 }
287 
288 /*
289  * Sysfs Interface
290  */
291 
292 struct threshold_attr {
293 	struct attribute attr;
294 	ssize_t (*show) (struct threshold_block *, char *);
295 	ssize_t (*store) (struct threshold_block *, const char *, size_t count);
296 };
297 
298 #define SHOW_FIELDS(name)						\
299 static ssize_t show_ ## name(struct threshold_block *b, char *buf)	\
300 {									\
301 	return sprintf(buf, "%lx\n", (unsigned long) b->name);		\
302 }
303 SHOW_FIELDS(interrupt_enable)
SHOW_FIELDS(threshold_limit)304 SHOW_FIELDS(threshold_limit)
305 
306 static ssize_t
307 store_interrupt_enable(struct threshold_block *b, const char *buf, size_t size)
308 {
309 	struct thresh_restart tr;
310 	unsigned long new;
311 
312 	if (strict_strtoul(buf, 0, &new) < 0)
313 		return -EINVAL;
314 
315 	b->interrupt_enable = !!new;
316 
317 	memset(&tr, 0, sizeof(tr));
318 	tr.b		= b;
319 
320 	smp_call_function_single(b->cpu, threshold_restart_bank, &tr, 1);
321 
322 	return size;
323 }
324 
325 static ssize_t
store_threshold_limit(struct threshold_block * b,const char * buf,size_t size)326 store_threshold_limit(struct threshold_block *b, const char *buf, size_t size)
327 {
328 	struct thresh_restart tr;
329 	unsigned long new;
330 
331 	if (strict_strtoul(buf, 0, &new) < 0)
332 		return -EINVAL;
333 
334 	if (new > THRESHOLD_MAX)
335 		new = THRESHOLD_MAX;
336 	if (new < 1)
337 		new = 1;
338 
339 	memset(&tr, 0, sizeof(tr));
340 	tr.old_limit = b->threshold_limit;
341 	b->threshold_limit = new;
342 	tr.b = b;
343 
344 	smp_call_function_single(b->cpu, threshold_restart_bank, &tr, 1);
345 
346 	return size;
347 }
348 
349 struct threshold_block_cross_cpu {
350 	struct threshold_block	*tb;
351 	long			retval;
352 };
353 
local_error_count_handler(void * _tbcc)354 static void local_error_count_handler(void *_tbcc)
355 {
356 	struct threshold_block_cross_cpu *tbcc = _tbcc;
357 	struct threshold_block *b = tbcc->tb;
358 	u32 low, high;
359 
360 	rdmsr(b->address, low, high);
361 	tbcc->retval = (high & 0xFFF) - (THRESHOLD_MAX - b->threshold_limit);
362 }
363 
show_error_count(struct threshold_block * b,char * buf)364 static ssize_t show_error_count(struct threshold_block *b, char *buf)
365 {
366 	struct threshold_block_cross_cpu tbcc = { .tb = b, };
367 
368 	smp_call_function_single(b->cpu, local_error_count_handler, &tbcc, 1);
369 	return sprintf(buf, "%lx\n", tbcc.retval);
370 }
371 
store_error_count(struct threshold_block * b,const char * buf,size_t count)372 static ssize_t store_error_count(struct threshold_block *b,
373 				 const char *buf, size_t count)
374 {
375 	struct thresh_restart tr = { .b = b, .reset = 1, .old_limit = 0 };
376 
377 	smp_call_function_single(b->cpu, threshold_restart_bank, &tr, 1);
378 	return 1;
379 }
380 
381 #define RW_ATTR(val)							\
382 static struct threshold_attr val = {					\
383 	.attr	= {.name = __stringify(val), .mode = 0644 },		\
384 	.show	= show_## val,						\
385 	.store	= store_## val,						\
386 };
387 
388 RW_ATTR(interrupt_enable);
389 RW_ATTR(threshold_limit);
390 RW_ATTR(error_count);
391 
392 static struct attribute *default_attrs[] = {
393 	&interrupt_enable.attr,
394 	&threshold_limit.attr,
395 	&error_count.attr,
396 	NULL
397 };
398 
399 #define to_block(k)	container_of(k, struct threshold_block, kobj)
400 #define to_attr(a)	container_of(a, struct threshold_attr, attr)
401 
show(struct kobject * kobj,struct attribute * attr,char * buf)402 static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
403 {
404 	struct threshold_block *b = to_block(kobj);
405 	struct threshold_attr *a = to_attr(attr);
406 	ssize_t ret;
407 
408 	ret = a->show ? a->show(b, buf) : -EIO;
409 
410 	return ret;
411 }
412 
store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)413 static ssize_t store(struct kobject *kobj, struct attribute *attr,
414 		     const char *buf, size_t count)
415 {
416 	struct threshold_block *b = to_block(kobj);
417 	struct threshold_attr *a = to_attr(attr);
418 	ssize_t ret;
419 
420 	ret = a->store ? a->store(b, buf, count) : -EIO;
421 
422 	return ret;
423 }
424 
425 static const struct sysfs_ops threshold_ops = {
426 	.show			= show,
427 	.store			= store,
428 };
429 
430 static struct kobj_type threshold_ktype = {
431 	.sysfs_ops		= &threshold_ops,
432 	.default_attrs		= default_attrs,
433 };
434 
allocate_threshold_blocks(unsigned int cpu,unsigned int bank,unsigned int block,u32 address)435 static __cpuinit int allocate_threshold_blocks(unsigned int cpu,
436 					       unsigned int bank,
437 					       unsigned int block,
438 					       u32 address)
439 {
440 	struct threshold_block *b = NULL;
441 	u32 low, high;
442 	int err;
443 
444 	if ((bank >= NR_BANKS) || (block >= NR_BLOCKS))
445 		return 0;
446 
447 	if (rdmsr_safe_on_cpu(cpu, address, &low, &high))
448 		return 0;
449 
450 	if (!(high & MASK_VALID_HI)) {
451 		if (block)
452 			goto recurse;
453 		else
454 			return 0;
455 	}
456 
457 	if (!(high & MASK_CNTP_HI)  ||
458 	     (high & MASK_LOCKED_HI))
459 		goto recurse;
460 
461 	b = kzalloc(sizeof(struct threshold_block), GFP_KERNEL);
462 	if (!b)
463 		return -ENOMEM;
464 
465 	b->block		= block;
466 	b->bank			= bank;
467 	b->cpu			= cpu;
468 	b->address		= address;
469 	b->interrupt_enable	= 0;
470 	b->threshold_limit	= THRESHOLD_MAX;
471 
472 	INIT_LIST_HEAD(&b->miscj);
473 
474 	if (per_cpu(threshold_banks, cpu)[bank]->blocks) {
475 		list_add(&b->miscj,
476 			 &per_cpu(threshold_banks, cpu)[bank]->blocks->miscj);
477 	} else {
478 		per_cpu(threshold_banks, cpu)[bank]->blocks = b;
479 	}
480 
481 	err = kobject_init_and_add(&b->kobj, &threshold_ktype,
482 				   per_cpu(threshold_banks, cpu)[bank]->kobj,
483 				   "misc%i", block);
484 	if (err)
485 		goto out_free;
486 recurse:
487 	if (!block) {
488 		address = (low & MASK_BLKPTR_LO) >> 21;
489 		if (!address)
490 			return 0;
491 		address += MCG_XBLK_ADDR;
492 	} else {
493 		++address;
494 	}
495 
496 	err = allocate_threshold_blocks(cpu, bank, ++block, address);
497 	if (err)
498 		goto out_free;
499 
500 	if (b)
501 		kobject_uevent(&b->kobj, KOBJ_ADD);
502 
503 	return err;
504 
505 out_free:
506 	if (b) {
507 		kobject_put(&b->kobj);
508 		list_del(&b->miscj);
509 		kfree(b);
510 	}
511 	return err;
512 }
513 
514 static __cpuinit long
local_allocate_threshold_blocks(int cpu,unsigned int bank)515 local_allocate_threshold_blocks(int cpu, unsigned int bank)
516 {
517 	return allocate_threshold_blocks(cpu, bank, 0,
518 					 MSR_IA32_MC0_MISC + bank * 4);
519 }
520 
521 /* symlinks sibling shared banks to first core.  first core owns dir/files. */
threshold_create_bank(unsigned int cpu,unsigned int bank)522 static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
523 {
524 	int i, err = 0;
525 	struct threshold_bank *b = NULL;
526 	struct device *dev = mce_device[cpu];
527 	char name[32];
528 
529 	sprintf(name, "threshold_bank%i", bank);
530 
531 #ifdef CONFIG_SMP
532 	if (cpu_data(cpu).cpu_core_id && shared_bank[bank]) {	/* symlink */
533 		i = cpumask_first(cpu_llc_shared_mask(cpu));
534 
535 		/* first core not up yet */
536 		if (cpu_data(i).cpu_core_id)
537 			goto out;
538 
539 		/* already linked */
540 		if (per_cpu(threshold_banks, cpu)[bank])
541 			goto out;
542 
543 		b = per_cpu(threshold_banks, i)[bank];
544 
545 		if (!b)
546 			goto out;
547 
548 		err = sysfs_create_link(&dev->kobj, b->kobj, name);
549 		if (err)
550 			goto out;
551 
552 		cpumask_copy(b->cpus, cpu_llc_shared_mask(cpu));
553 		per_cpu(threshold_banks, cpu)[bank] = b;
554 
555 		goto out;
556 	}
557 #endif
558 
559 	b = kzalloc(sizeof(struct threshold_bank), GFP_KERNEL);
560 	if (!b) {
561 		err = -ENOMEM;
562 		goto out;
563 	}
564 	if (!zalloc_cpumask_var(&b->cpus, GFP_KERNEL)) {
565 		kfree(b);
566 		err = -ENOMEM;
567 		goto out;
568 	}
569 
570 	b->kobj = kobject_create_and_add(name, &dev->kobj);
571 	if (!b->kobj)
572 		goto out_free;
573 
574 #ifndef CONFIG_SMP
575 	cpumask_setall(b->cpus);
576 #else
577 	cpumask_set_cpu(cpu, b->cpus);
578 #endif
579 
580 	per_cpu(threshold_banks, cpu)[bank] = b;
581 
582 	err = local_allocate_threshold_blocks(cpu, bank);
583 	if (err)
584 		goto out_free;
585 
586 	for_each_cpu(i, b->cpus) {
587 		if (i == cpu)
588 			continue;
589 
590 		dev = mce_device[i];
591 		if (dev)
592 			err = sysfs_create_link(&dev->kobj,b->kobj, name);
593 		if (err)
594 			goto out;
595 
596 		per_cpu(threshold_banks, i)[bank] = b;
597 	}
598 
599 	goto out;
600 
601 out_free:
602 	per_cpu(threshold_banks, cpu)[bank] = NULL;
603 	free_cpumask_var(b->cpus);
604 	kfree(b);
605 out:
606 	return err;
607 }
608 
609 /* create dir/files for all valid threshold banks */
threshold_create_device(unsigned int cpu)610 static __cpuinit int threshold_create_device(unsigned int cpu)
611 {
612 	unsigned int bank;
613 	int err = 0;
614 
615 	for (bank = 0; bank < NR_BANKS; ++bank) {
616 		if (!(per_cpu(bank_map, cpu) & (1 << bank)))
617 			continue;
618 		err = threshold_create_bank(cpu, bank);
619 		if (err)
620 			return err;
621 	}
622 
623 	return err;
624 }
625 
626 /*
627  * let's be hotplug friendly.
628  * in case of multiple core processors, the first core always takes ownership
629  *   of shared sysfs dir/files, and rest of the cores will be symlinked to it.
630  */
631 
deallocate_threshold_block(unsigned int cpu,unsigned int bank)632 static void deallocate_threshold_block(unsigned int cpu,
633 						 unsigned int bank)
634 {
635 	struct threshold_block *pos = NULL;
636 	struct threshold_block *tmp = NULL;
637 	struct threshold_bank *head = per_cpu(threshold_banks, cpu)[bank];
638 
639 	if (!head)
640 		return;
641 
642 	list_for_each_entry_safe(pos, tmp, &head->blocks->miscj, miscj) {
643 		kobject_put(&pos->kobj);
644 		list_del(&pos->miscj);
645 		kfree(pos);
646 	}
647 
648 	kfree(per_cpu(threshold_banks, cpu)[bank]->blocks);
649 	per_cpu(threshold_banks, cpu)[bank]->blocks = NULL;
650 }
651 
threshold_remove_bank(unsigned int cpu,int bank)652 static void threshold_remove_bank(unsigned int cpu, int bank)
653 {
654 	struct threshold_bank *b;
655 	struct device *dev;
656 	char name[32];
657 	int i = 0;
658 
659 	b = per_cpu(threshold_banks, cpu)[bank];
660 	if (!b)
661 		return;
662 	if (!b->blocks)
663 		goto free_out;
664 
665 	sprintf(name, "threshold_bank%i", bank);
666 
667 #ifdef CONFIG_SMP
668 	/* sibling symlink */
669 	if (shared_bank[bank] && b->blocks->cpu != cpu) {
670 		sysfs_remove_link(&mce_device[cpu]->kobj, name);
671 		per_cpu(threshold_banks, cpu)[bank] = NULL;
672 
673 		return;
674 	}
675 #endif
676 
677 	/* remove all sibling symlinks before unregistering */
678 	for_each_cpu(i, b->cpus) {
679 		if (i == cpu)
680 			continue;
681 
682 		dev = mce_device[i];
683 		if (dev)
684 			sysfs_remove_link(&dev->kobj, name);
685 		per_cpu(threshold_banks, i)[bank] = NULL;
686 	}
687 
688 	deallocate_threshold_block(cpu, bank);
689 
690 free_out:
691 	kobject_del(b->kobj);
692 	kobject_put(b->kobj);
693 	free_cpumask_var(b->cpus);
694 	kfree(b);
695 	per_cpu(threshold_banks, cpu)[bank] = NULL;
696 }
697 
threshold_remove_device(unsigned int cpu)698 static void threshold_remove_device(unsigned int cpu)
699 {
700 	unsigned int bank;
701 
702 	for (bank = 0; bank < NR_BANKS; ++bank) {
703 		if (!(per_cpu(bank_map, cpu) & (1 << bank)))
704 			continue;
705 		threshold_remove_bank(cpu, bank);
706 	}
707 }
708 
709 /* get notified when a cpu comes on/off */
710 static void __cpuinit
amd_64_threshold_cpu_callback(unsigned long action,unsigned int cpu)711 amd_64_threshold_cpu_callback(unsigned long action, unsigned int cpu)
712 {
713 	switch (action) {
714 	case CPU_ONLINE:
715 	case CPU_ONLINE_FROZEN:
716 		threshold_create_device(cpu);
717 		break;
718 	case CPU_DEAD:
719 	case CPU_DEAD_FROZEN:
720 		threshold_remove_device(cpu);
721 		break;
722 	default:
723 		break;
724 	}
725 }
726 
threshold_init_device(void)727 static __init int threshold_init_device(void)
728 {
729 	unsigned lcpu = 0;
730 
731 	/* to hit CPUs online before the notifier is up */
732 	for_each_online_cpu(lcpu) {
733 		int err = threshold_create_device(lcpu);
734 
735 		if (err)
736 			return err;
737 	}
738 	threshold_cpu_callback = amd_64_threshold_cpu_callback;
739 
740 	return 0;
741 }
742 device_initcall(threshold_init_device);
743