xref: /openbmc/linux/arch/x86/kernel/cpu/mce/inject.c (revision d6fc9fcb)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Machine check injection support.
4  * Copyright 2008 Intel Corporation.
5  *
6  * Authors:
7  * Andi Kleen
8  * Ying Huang
9  *
10  * The AMD part (from mce_amd_inj.c): a simple MCE injection facility
11  * for testing different aspects of the RAS code. This driver should be
12  * built as module so that it can be loaded on production kernels for
13  * testing purposes.
14  *
15  * Copyright (c) 2010-17:  Borislav Petkov <bp@alien8.de>
16  *			   Advanced Micro Devices Inc.
17  */
18 
19 #include <linux/cpu.h>
20 #include <linux/debugfs.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/notifier.h>
24 #include <linux/pci.h>
25 #include <linux/uaccess.h>
26 
27 #include <asm/amd_nb.h>
28 #include <asm/apic.h>
29 #include <asm/irq_vectors.h>
30 #include <asm/mce.h>
31 #include <asm/nmi.h>
32 #include <asm/smp.h>
33 
34 #include "internal.h"
35 
36 /*
37  * Collect all the MCi_XXX settings
38  */
39 static struct mce i_mce;
40 static struct dentry *dfs_inj;
41 
42 #define MAX_FLAG_OPT_SIZE	4
43 #define NBCFG			0x44
44 
45 enum injection_type {
46 	SW_INJ = 0,	/* SW injection, simply decode the error */
47 	HW_INJ,		/* Trigger a #MC */
48 	DFR_INT_INJ,    /* Trigger Deferred error interrupt */
49 	THR_INT_INJ,    /* Trigger threshold interrupt */
50 	N_INJ_TYPES,
51 };
52 
53 static const char * const flags_options[] = {
54 	[SW_INJ] = "sw",
55 	[HW_INJ] = "hw",
56 	[DFR_INT_INJ] = "df",
57 	[THR_INT_INJ] = "th",
58 	NULL
59 };
60 
61 /* Set default injection to SW_INJ */
62 static enum injection_type inj_type = SW_INJ;
63 
64 #define MCE_INJECT_SET(reg)						\
65 static int inj_##reg##_set(void *data, u64 val)				\
66 {									\
67 	struct mce *m = (struct mce *)data;				\
68 									\
69 	m->reg = val;							\
70 	return 0;							\
71 }
72 
73 MCE_INJECT_SET(status);
74 MCE_INJECT_SET(misc);
75 MCE_INJECT_SET(addr);
76 MCE_INJECT_SET(synd);
77 
78 #define MCE_INJECT_GET(reg)						\
79 static int inj_##reg##_get(void *data, u64 *val)			\
80 {									\
81 	struct mce *m = (struct mce *)data;				\
82 									\
83 	*val = m->reg;							\
84 	return 0;							\
85 }
86 
87 MCE_INJECT_GET(status);
88 MCE_INJECT_GET(misc);
89 MCE_INJECT_GET(addr);
90 MCE_INJECT_GET(synd);
91 
92 DEFINE_SIMPLE_ATTRIBUTE(status_fops, inj_status_get, inj_status_set, "%llx\n");
93 DEFINE_SIMPLE_ATTRIBUTE(misc_fops, inj_misc_get, inj_misc_set, "%llx\n");
94 DEFINE_SIMPLE_ATTRIBUTE(addr_fops, inj_addr_get, inj_addr_set, "%llx\n");
95 DEFINE_SIMPLE_ATTRIBUTE(synd_fops, inj_synd_get, inj_synd_set, "%llx\n");
96 
97 static void setup_inj_struct(struct mce *m)
98 {
99 	memset(m, 0, sizeof(struct mce));
100 
101 	m->cpuvendor = boot_cpu_data.x86_vendor;
102 	m->time	     = ktime_get_real_seconds();
103 	m->cpuid     = cpuid_eax(1);
104 	m->microcode = boot_cpu_data.microcode;
105 }
106 
107 /* Update fake mce registers on current CPU. */
108 static void inject_mce(struct mce *m)
109 {
110 	struct mce *i = &per_cpu(injectm, m->extcpu);
111 
112 	/* Make sure no one reads partially written injectm */
113 	i->finished = 0;
114 	mb();
115 	m->finished = 0;
116 	/* First set the fields after finished */
117 	i->extcpu = m->extcpu;
118 	mb();
119 	/* Now write record in order, finished last (except above) */
120 	memcpy(i, m, sizeof(struct mce));
121 	/* Finally activate it */
122 	mb();
123 	i->finished = 1;
124 }
125 
126 static void raise_poll(struct mce *m)
127 {
128 	unsigned long flags;
129 	mce_banks_t b;
130 
131 	memset(&b, 0xff, sizeof(mce_banks_t));
132 	local_irq_save(flags);
133 	machine_check_poll(0, &b);
134 	local_irq_restore(flags);
135 	m->finished = 0;
136 }
137 
138 static void raise_exception(struct mce *m, struct pt_regs *pregs)
139 {
140 	struct pt_regs regs;
141 	unsigned long flags;
142 
143 	if (!pregs) {
144 		memset(&regs, 0, sizeof(struct pt_regs));
145 		regs.ip = m->ip;
146 		regs.cs = m->cs;
147 		pregs = &regs;
148 	}
149 	/* in mcheck exeception handler, irq will be disabled */
150 	local_irq_save(flags);
151 	do_machine_check(pregs, 0);
152 	local_irq_restore(flags);
153 	m->finished = 0;
154 }
155 
156 static cpumask_var_t mce_inject_cpumask;
157 static DEFINE_MUTEX(mce_inject_mutex);
158 
159 static int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
160 {
161 	int cpu = smp_processor_id();
162 	struct mce *m = this_cpu_ptr(&injectm);
163 	if (!cpumask_test_cpu(cpu, mce_inject_cpumask))
164 		return NMI_DONE;
165 	cpumask_clear_cpu(cpu, mce_inject_cpumask);
166 	if (m->inject_flags & MCJ_EXCEPTION)
167 		raise_exception(m, regs);
168 	else if (m->status)
169 		raise_poll(m);
170 	return NMI_HANDLED;
171 }
172 
173 static void mce_irq_ipi(void *info)
174 {
175 	int cpu = smp_processor_id();
176 	struct mce *m = this_cpu_ptr(&injectm);
177 
178 	if (cpumask_test_cpu(cpu, mce_inject_cpumask) &&
179 			m->inject_flags & MCJ_EXCEPTION) {
180 		cpumask_clear_cpu(cpu, mce_inject_cpumask);
181 		raise_exception(m, NULL);
182 	}
183 }
184 
185 /* Inject mce on current CPU */
186 static int raise_local(void)
187 {
188 	struct mce *m = this_cpu_ptr(&injectm);
189 	int context = MCJ_CTX(m->inject_flags);
190 	int ret = 0;
191 	int cpu = m->extcpu;
192 
193 	if (m->inject_flags & MCJ_EXCEPTION) {
194 		pr_info("Triggering MCE exception on CPU %d\n", cpu);
195 		switch (context) {
196 		case MCJ_CTX_IRQ:
197 			/*
198 			 * Could do more to fake interrupts like
199 			 * calling irq_enter, but the necessary
200 			 * machinery isn't exported currently.
201 			 */
202 			/*FALL THROUGH*/
203 		case MCJ_CTX_PROCESS:
204 			raise_exception(m, NULL);
205 			break;
206 		default:
207 			pr_info("Invalid MCE context\n");
208 			ret = -EINVAL;
209 		}
210 		pr_info("MCE exception done on CPU %d\n", cpu);
211 	} else if (m->status) {
212 		pr_info("Starting machine check poll CPU %d\n", cpu);
213 		raise_poll(m);
214 		mce_notify_irq();
215 		pr_info("Machine check poll done on CPU %d\n", cpu);
216 	} else
217 		m->finished = 0;
218 
219 	return ret;
220 }
221 
222 static void __maybe_unused raise_mce(struct mce *m)
223 {
224 	int context = MCJ_CTX(m->inject_flags);
225 
226 	inject_mce(m);
227 
228 	if (context == MCJ_CTX_RANDOM)
229 		return;
230 
231 	if (m->inject_flags & (MCJ_IRQ_BROADCAST | MCJ_NMI_BROADCAST)) {
232 		unsigned long start;
233 		int cpu;
234 
235 		get_online_cpus();
236 		cpumask_copy(mce_inject_cpumask, cpu_online_mask);
237 		cpumask_clear_cpu(get_cpu(), mce_inject_cpumask);
238 		for_each_online_cpu(cpu) {
239 			struct mce *mcpu = &per_cpu(injectm, cpu);
240 			if (!mcpu->finished ||
241 			    MCJ_CTX(mcpu->inject_flags) != MCJ_CTX_RANDOM)
242 				cpumask_clear_cpu(cpu, mce_inject_cpumask);
243 		}
244 		if (!cpumask_empty(mce_inject_cpumask)) {
245 			if (m->inject_flags & MCJ_IRQ_BROADCAST) {
246 				/*
247 				 * don't wait because mce_irq_ipi is necessary
248 				 * to be sync with following raise_local
249 				 */
250 				preempt_disable();
251 				smp_call_function_many(mce_inject_cpumask,
252 					mce_irq_ipi, NULL, 0);
253 				preempt_enable();
254 			} else if (m->inject_flags & MCJ_NMI_BROADCAST)
255 				apic->send_IPI_mask(mce_inject_cpumask,
256 						NMI_VECTOR);
257 		}
258 		start = jiffies;
259 		while (!cpumask_empty(mce_inject_cpumask)) {
260 			if (!time_before(jiffies, start + 2*HZ)) {
261 				pr_err("Timeout waiting for mce inject %lx\n",
262 					*cpumask_bits(mce_inject_cpumask));
263 				break;
264 			}
265 			cpu_relax();
266 		}
267 		raise_local();
268 		put_cpu();
269 		put_online_cpus();
270 	} else {
271 		preempt_disable();
272 		raise_local();
273 		preempt_enable();
274 	}
275 }
276 
277 static int mce_inject_raise(struct notifier_block *nb, unsigned long val,
278 			    void *data)
279 {
280 	struct mce *m = (struct mce *)data;
281 
282 	if (!m)
283 		return NOTIFY_DONE;
284 
285 	mutex_lock(&mce_inject_mutex);
286 	raise_mce(m);
287 	mutex_unlock(&mce_inject_mutex);
288 
289 	return NOTIFY_DONE;
290 }
291 
292 static struct notifier_block inject_nb = {
293 	.notifier_call  = mce_inject_raise,
294 };
295 
296 /*
297  * Caller needs to be make sure this cpu doesn't disappear
298  * from under us, i.e.: get_cpu/put_cpu.
299  */
300 static int toggle_hw_mce_inject(unsigned int cpu, bool enable)
301 {
302 	u32 l, h;
303 	int err;
304 
305 	err = rdmsr_on_cpu(cpu, MSR_K7_HWCR, &l, &h);
306 	if (err) {
307 		pr_err("%s: error reading HWCR\n", __func__);
308 		return err;
309 	}
310 
311 	enable ? (l |= BIT(18)) : (l &= ~BIT(18));
312 
313 	err = wrmsr_on_cpu(cpu, MSR_K7_HWCR, l, h);
314 	if (err)
315 		pr_err("%s: error writing HWCR\n", __func__);
316 
317 	return err;
318 }
319 
320 static int __set_inj(const char *buf)
321 {
322 	int i;
323 
324 	for (i = 0; i < N_INJ_TYPES; i++) {
325 		if (!strncmp(flags_options[i], buf, strlen(flags_options[i]))) {
326 			inj_type = i;
327 			return 0;
328 		}
329 	}
330 	return -EINVAL;
331 }
332 
333 static ssize_t flags_read(struct file *filp, char __user *ubuf,
334 			  size_t cnt, loff_t *ppos)
335 {
336 	char buf[MAX_FLAG_OPT_SIZE];
337 	int n;
338 
339 	n = sprintf(buf, "%s\n", flags_options[inj_type]);
340 
341 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
342 }
343 
344 static ssize_t flags_write(struct file *filp, const char __user *ubuf,
345 			   size_t cnt, loff_t *ppos)
346 {
347 	char buf[MAX_FLAG_OPT_SIZE], *__buf;
348 	int err;
349 
350 	if (cnt > MAX_FLAG_OPT_SIZE)
351 		return -EINVAL;
352 
353 	if (copy_from_user(&buf, ubuf, cnt))
354 		return -EFAULT;
355 
356 	buf[cnt - 1] = 0;
357 
358 	/* strip whitespace */
359 	__buf = strstrip(buf);
360 
361 	err = __set_inj(__buf);
362 	if (err) {
363 		pr_err("%s: Invalid flags value: %s\n", __func__, __buf);
364 		return err;
365 	}
366 
367 	*ppos += cnt;
368 
369 	return cnt;
370 }
371 
372 static const struct file_operations flags_fops = {
373 	.read           = flags_read,
374 	.write          = flags_write,
375 	.llseek         = generic_file_llseek,
376 };
377 
378 /*
379  * On which CPU to inject?
380  */
381 MCE_INJECT_GET(extcpu);
382 
383 static int inj_extcpu_set(void *data, u64 val)
384 {
385 	struct mce *m = (struct mce *)data;
386 
387 	if (val >= nr_cpu_ids || !cpu_online(val)) {
388 		pr_err("%s: Invalid CPU: %llu\n", __func__, val);
389 		return -EINVAL;
390 	}
391 	m->extcpu = val;
392 	return 0;
393 }
394 
395 DEFINE_SIMPLE_ATTRIBUTE(extcpu_fops, inj_extcpu_get, inj_extcpu_set, "%llu\n");
396 
397 static void trigger_mce(void *info)
398 {
399 	asm volatile("int $18");
400 }
401 
402 static void trigger_dfr_int(void *info)
403 {
404 	asm volatile("int %0" :: "i" (DEFERRED_ERROR_VECTOR));
405 }
406 
407 static void trigger_thr_int(void *info)
408 {
409 	asm volatile("int %0" :: "i" (THRESHOLD_APIC_VECTOR));
410 }
411 
412 static u32 get_nbc_for_node(int node_id)
413 {
414 	struct cpuinfo_x86 *c = &boot_cpu_data;
415 	u32 cores_per_node;
416 
417 	cores_per_node = (c->x86_max_cores * smp_num_siblings) / amd_get_nodes_per_socket();
418 
419 	return cores_per_node * node_id;
420 }
421 
422 static void toggle_nb_mca_mst_cpu(u16 nid)
423 {
424 	struct amd_northbridge *nb;
425 	struct pci_dev *F3;
426 	u32 val;
427 	int err;
428 
429 	nb = node_to_amd_nb(nid);
430 	if (!nb)
431 		return;
432 
433 	F3 = nb->misc;
434 	if (!F3)
435 		return;
436 
437 	err = pci_read_config_dword(F3, NBCFG, &val);
438 	if (err) {
439 		pr_err("%s: Error reading F%dx%03x.\n",
440 		       __func__, PCI_FUNC(F3->devfn), NBCFG);
441 		return;
442 	}
443 
444 	if (val & BIT(27))
445 		return;
446 
447 	pr_err("%s: Set D18F3x44[NbMcaToMstCpuEn] which BIOS hasn't done.\n",
448 	       __func__);
449 
450 	val |= BIT(27);
451 	err = pci_write_config_dword(F3, NBCFG, val);
452 	if (err)
453 		pr_err("%s: Error writing F%dx%03x.\n",
454 		       __func__, PCI_FUNC(F3->devfn), NBCFG);
455 }
456 
457 static void prepare_msrs(void *info)
458 {
459 	struct mce m = *(struct mce *)info;
460 	u8 b = m.bank;
461 
462 	wrmsrl(MSR_IA32_MCG_STATUS, m.mcgstatus);
463 
464 	if (boot_cpu_has(X86_FEATURE_SMCA)) {
465 		if (m.inject_flags == DFR_INT_INJ) {
466 			wrmsrl(MSR_AMD64_SMCA_MCx_DESTAT(b), m.status);
467 			wrmsrl(MSR_AMD64_SMCA_MCx_DEADDR(b), m.addr);
468 		} else {
469 			wrmsrl(MSR_AMD64_SMCA_MCx_STATUS(b), m.status);
470 			wrmsrl(MSR_AMD64_SMCA_MCx_ADDR(b), m.addr);
471 		}
472 
473 		wrmsrl(MSR_AMD64_SMCA_MCx_MISC(b), m.misc);
474 		wrmsrl(MSR_AMD64_SMCA_MCx_SYND(b), m.synd);
475 	} else {
476 		wrmsrl(MSR_IA32_MCx_STATUS(b), m.status);
477 		wrmsrl(MSR_IA32_MCx_ADDR(b), m.addr);
478 		wrmsrl(MSR_IA32_MCx_MISC(b), m.misc);
479 	}
480 }
481 
482 static void do_inject(void)
483 {
484 	u64 mcg_status = 0;
485 	unsigned int cpu = i_mce.extcpu;
486 	u8 b = i_mce.bank;
487 
488 	i_mce.tsc = rdtsc_ordered();
489 
490 	if (i_mce.misc)
491 		i_mce.status |= MCI_STATUS_MISCV;
492 
493 	if (i_mce.synd)
494 		i_mce.status |= MCI_STATUS_SYNDV;
495 
496 	if (inj_type == SW_INJ) {
497 		mce_inject_log(&i_mce);
498 		return;
499 	}
500 
501 	/* prep MCE global settings for the injection */
502 	mcg_status = MCG_STATUS_MCIP | MCG_STATUS_EIPV;
503 
504 	if (!(i_mce.status & MCI_STATUS_PCC))
505 		mcg_status |= MCG_STATUS_RIPV;
506 
507 	/*
508 	 * Ensure necessary status bits for deferred errors:
509 	 * - MCx_STATUS[Deferred]: make sure it is a deferred error
510 	 * - MCx_STATUS[UC] cleared: deferred errors are _not_ UC
511 	 */
512 	if (inj_type == DFR_INT_INJ) {
513 		i_mce.status |= MCI_STATUS_DEFERRED;
514 		i_mce.status |= (i_mce.status & ~MCI_STATUS_UC);
515 	}
516 
517 	/*
518 	 * For multi node CPUs, logging and reporting of bank 4 errors happens
519 	 * only on the node base core. Refer to D18F3x44[NbMcaToMstCpuEn] for
520 	 * Fam10h and later BKDGs.
521 	 */
522 	if (boot_cpu_has(X86_FEATURE_AMD_DCM) &&
523 	    b == 4 &&
524 	    boot_cpu_data.x86 < 0x17) {
525 		toggle_nb_mca_mst_cpu(amd_get_nb_id(cpu));
526 		cpu = get_nbc_for_node(amd_get_nb_id(cpu));
527 	}
528 
529 	get_online_cpus();
530 	if (!cpu_online(cpu))
531 		goto err;
532 
533 	toggle_hw_mce_inject(cpu, true);
534 
535 	i_mce.mcgstatus = mcg_status;
536 	i_mce.inject_flags = inj_type;
537 	smp_call_function_single(cpu, prepare_msrs, &i_mce, 0);
538 
539 	toggle_hw_mce_inject(cpu, false);
540 
541 	switch (inj_type) {
542 	case DFR_INT_INJ:
543 		smp_call_function_single(cpu, trigger_dfr_int, NULL, 0);
544 		break;
545 	case THR_INT_INJ:
546 		smp_call_function_single(cpu, trigger_thr_int, NULL, 0);
547 		break;
548 	default:
549 		smp_call_function_single(cpu, trigger_mce, NULL, 0);
550 	}
551 
552 err:
553 	put_online_cpus();
554 
555 }
556 
557 /*
558  * This denotes into which bank we're injecting and triggers
559  * the injection, at the same time.
560  */
561 static int inj_bank_set(void *data, u64 val)
562 {
563 	struct mce *m = (struct mce *)data;
564 	u8 n_banks;
565 	u64 cap;
566 
567 	/* Get bank count on target CPU so we can handle non-uniform values. */
568 	rdmsrl_on_cpu(m->extcpu, MSR_IA32_MCG_CAP, &cap);
569 	n_banks = cap & MCG_BANKCNT_MASK;
570 
571 	if (val >= n_banks) {
572 		pr_err("MCA bank %llu non-existent on CPU%d\n", val, m->extcpu);
573 		return -EINVAL;
574 	}
575 
576 	m->bank = val;
577 	do_inject();
578 
579 	/* Reset injection struct */
580 	setup_inj_struct(&i_mce);
581 
582 	return 0;
583 }
584 
585 MCE_INJECT_GET(bank);
586 
587 DEFINE_SIMPLE_ATTRIBUTE(bank_fops, inj_bank_get, inj_bank_set, "%llu\n");
588 
589 static const char readme_msg[] =
590 "Description of the files and their usages:\n"
591 "\n"
592 "Note1: i refers to the bank number below.\n"
593 "Note2: See respective BKDGs for the exact bit definitions of the files below\n"
594 "as they mirror the hardware registers.\n"
595 "\n"
596 "status:\t Set MCi_STATUS: the bits in that MSR control the error type and\n"
597 "\t attributes of the error which caused the MCE.\n"
598 "\n"
599 "misc:\t Set MCi_MISC: provide auxiliary info about the error. It is mostly\n"
600 "\t used for error thresholding purposes and its validity is indicated by\n"
601 "\t MCi_STATUS[MiscV].\n"
602 "\n"
603 "synd:\t Set MCi_SYND: provide syndrome info about the error. Only valid on\n"
604 "\t Scalable MCA systems, and its validity is indicated by MCi_STATUS[SyndV].\n"
605 "\n"
606 "addr:\t Error address value to be written to MCi_ADDR. Log address information\n"
607 "\t associated with the error.\n"
608 "\n"
609 "cpu:\t The CPU to inject the error on.\n"
610 "\n"
611 "bank:\t Specify the bank you want to inject the error into: the number of\n"
612 "\t banks in a processor varies and is family/model-specific, therefore, the\n"
613 "\t supplied value is sanity-checked. Setting the bank value also triggers the\n"
614 "\t injection.\n"
615 "\n"
616 "flags:\t Injection type to be performed. Writing to this file will trigger a\n"
617 "\t real machine check, an APIC interrupt or invoke the error decoder routines\n"
618 "\t for AMD processors.\n"
619 "\n"
620 "\t Allowed error injection types:\n"
621 "\t  - \"sw\": Software error injection. Decode error to a human-readable \n"
622 "\t    format only. Safe to use.\n"
623 "\t  - \"hw\": Hardware error injection. Causes the #MC exception handler to \n"
624 "\t    handle the error. Be warned: might cause system panic if MCi_STATUS[PCC] \n"
625 "\t    is set. Therefore, consider setting (debugfs_mountpoint)/mce/fake_panic \n"
626 "\t    before injecting.\n"
627 "\t  - \"df\": Trigger APIC interrupt for Deferred error. Causes deferred \n"
628 "\t    error APIC interrupt handler to handle the error if the feature is \n"
629 "\t    is present in hardware. \n"
630 "\t  - \"th\": Trigger APIC interrupt for Threshold errors. Causes threshold \n"
631 "\t    APIC interrupt handler to handle the error. \n"
632 "\n";
633 
634 static ssize_t
635 inj_readme_read(struct file *filp, char __user *ubuf,
636 		       size_t cnt, loff_t *ppos)
637 {
638 	return simple_read_from_buffer(ubuf, cnt, ppos,
639 					readme_msg, strlen(readme_msg));
640 }
641 
642 static const struct file_operations readme_fops = {
643 	.read		= inj_readme_read,
644 };
645 
646 static struct dfs_node {
647 	char *name;
648 	struct dentry *d;
649 	const struct file_operations *fops;
650 	umode_t perm;
651 } dfs_fls[] = {
652 	{ .name = "status",	.fops = &status_fops, .perm = S_IRUSR | S_IWUSR },
653 	{ .name = "misc",	.fops = &misc_fops,   .perm = S_IRUSR | S_IWUSR },
654 	{ .name = "addr",	.fops = &addr_fops,   .perm = S_IRUSR | S_IWUSR },
655 	{ .name = "synd",	.fops = &synd_fops,   .perm = S_IRUSR | S_IWUSR },
656 	{ .name = "bank",	.fops = &bank_fops,   .perm = S_IRUSR | S_IWUSR },
657 	{ .name = "flags",	.fops = &flags_fops,  .perm = S_IRUSR | S_IWUSR },
658 	{ .name = "cpu",	.fops = &extcpu_fops, .perm = S_IRUSR | S_IWUSR },
659 	{ .name = "README",	.fops = &readme_fops, .perm = S_IRUSR | S_IRGRP | S_IROTH },
660 };
661 
662 static int __init debugfs_init(void)
663 {
664 	unsigned int i;
665 
666 	dfs_inj = debugfs_create_dir("mce-inject", NULL);
667 	if (!dfs_inj)
668 		return -EINVAL;
669 
670 	for (i = 0; i < ARRAY_SIZE(dfs_fls); i++) {
671 		dfs_fls[i].d = debugfs_create_file(dfs_fls[i].name,
672 						    dfs_fls[i].perm,
673 						    dfs_inj,
674 						    &i_mce,
675 						    dfs_fls[i].fops);
676 
677 		if (!dfs_fls[i].d)
678 			goto err_dfs_add;
679 	}
680 
681 	return 0;
682 
683 err_dfs_add:
684 	while (i-- > 0)
685 		debugfs_remove(dfs_fls[i].d);
686 
687 	debugfs_remove(dfs_inj);
688 	dfs_inj = NULL;
689 
690 	return -ENODEV;
691 }
692 
693 static int __init inject_init(void)
694 {
695 	int err;
696 
697 	if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
698 		return -ENOMEM;
699 
700 	err = debugfs_init();
701 	if (err) {
702 		free_cpumask_var(mce_inject_cpumask);
703 		return err;
704 	}
705 
706 	register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0, "mce_notify");
707 	mce_register_injector_chain(&inject_nb);
708 
709 	setup_inj_struct(&i_mce);
710 
711 	pr_info("Machine check injector initialized\n");
712 
713 	return 0;
714 }
715 
716 static void __exit inject_exit(void)
717 {
718 
719 	mce_unregister_injector_chain(&inject_nb);
720 	unregister_nmi_handler(NMI_LOCAL, "mce_notify");
721 
722 	debugfs_remove_recursive(dfs_inj);
723 	dfs_inj = NULL;
724 
725 	memset(&dfs_fls, 0, sizeof(dfs_fls));
726 
727 	free_cpumask_var(mce_inject_cpumask);
728 }
729 
730 module_init(inject_init);
731 module_exit(inject_exit);
732 MODULE_LICENSE("GPL");
733