xref: /linux/drivers/acpi/apei/erst.c (revision 0a94608f0f7de9b1135ffea3546afe68eafef57f) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * APEI Error Record Serialization Table support
4  *
5  * ERST is a way provided by APEI to save and retrieve hardware error
6  * information to and from a persistent store.
7  *
8  * For more information about ERST, please refer to ACPI Specification
9  * version 4.0, section 17.4.
10  *
11  * Copyright 2010 Intel Corp.
12  *   Author: Huang Ying <ying.huang@intel.com>
13  */
14 
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/delay.h>
19 #include <linux/io.h>
20 #include <linux/acpi.h>
21 #include <linux/uaccess.h>
22 #include <linux/cper.h>
23 #include <linux/nmi.h>
24 #include <linux/hardirq.h>
25 #include <linux/pstore.h>
26 #include <linux/vmalloc.h>
27 #include <linux/mm.h> /* kvfree() */
28 #include <acpi/apei.h>
29 
30 #include "apei-internal.h"
31 
32 #undef pr_fmt
33 #define pr_fmt(fmt) "ERST: " fmt
34 
35 /* ERST command status */
36 #define ERST_STATUS_SUCCESS			0x0
37 #define ERST_STATUS_NOT_ENOUGH_SPACE		0x1
38 #define ERST_STATUS_HARDWARE_NOT_AVAILABLE	0x2
39 #define ERST_STATUS_FAILED			0x3
40 #define ERST_STATUS_RECORD_STORE_EMPTY		0x4
41 #define ERST_STATUS_RECORD_NOT_FOUND		0x5
42 
43 #define ERST_TAB_ENTRY(tab)						\
44 	((struct acpi_whea_header *)((char *)(tab) +			\
45 				     sizeof(struct acpi_table_erst)))
46 
47 #define SPIN_UNIT		100			/* 100ns */
48 /* Firmware should respond within 1 milliseconds */
49 #define FIRMWARE_TIMEOUT	(1 * NSEC_PER_MSEC)
50 #define FIRMWARE_MAX_STALL	50			/* 50us */
51 
52 int erst_disable;
53 EXPORT_SYMBOL_GPL(erst_disable);
54 
55 static struct acpi_table_erst *erst_tab;
56 
57 /* ERST Error Log Address Range attributes */
58 #define ERST_RANGE_RESERVED	0x0001
59 #define ERST_RANGE_NVRAM	0x0002
60 #define ERST_RANGE_SLOW		0x0004
61 
62 /*
63  * ERST Error Log Address Range, used as buffer for reading/writing
64  * error records.
65  */
66 static struct erst_erange {
67 	u64 base;
68 	u64 size;
69 	void __iomem *vaddr;
70 	u32 attr;
71 } erst_erange;
72 
73 /*
74  * Prevent ERST interpreter to run simultaneously, because the
75  * corresponding firmware implementation may not work properly when
76  * invoked simultaneously.
77  *
78  * It is used to provide exclusive accessing for ERST Error Log
79  * Address Range too.
80  */
81 static DEFINE_RAW_SPINLOCK(erst_lock);
82 
83 static inline int erst_errno(int command_status)
84 {
85 	switch (command_status) {
86 	case ERST_STATUS_SUCCESS:
87 		return 0;
88 	case ERST_STATUS_HARDWARE_NOT_AVAILABLE:
89 		return -ENODEV;
90 	case ERST_STATUS_NOT_ENOUGH_SPACE:
91 		return -ENOSPC;
92 	case ERST_STATUS_RECORD_STORE_EMPTY:
93 	case ERST_STATUS_RECORD_NOT_FOUND:
94 		return -ENOENT;
95 	default:
96 		return -EINVAL;
97 	}
98 }
99 
100 static int erst_timedout(u64 *t, u64 spin_unit)
101 {
102 	if ((s64)*t < spin_unit) {
103 		pr_warn(FW_WARN "Firmware does not respond in time.\n");
104 		return 1;
105 	}
106 	*t -= spin_unit;
107 	ndelay(spin_unit);
108 	touch_nmi_watchdog();
109 	return 0;
110 }
111 
112 static int erst_exec_load_var1(struct apei_exec_context *ctx,
113 			       struct acpi_whea_header *entry)
114 {
115 	return __apei_exec_read_register(entry, &ctx->var1);
116 }
117 
118 static int erst_exec_load_var2(struct apei_exec_context *ctx,
119 			       struct acpi_whea_header *entry)
120 {
121 	return __apei_exec_read_register(entry, &ctx->var2);
122 }
123 
124 static int erst_exec_store_var1(struct apei_exec_context *ctx,
125 				struct acpi_whea_header *entry)
126 {
127 	return __apei_exec_write_register(entry, ctx->var1);
128 }
129 
130 static int erst_exec_add(struct apei_exec_context *ctx,
131 			 struct acpi_whea_header *entry)
132 {
133 	ctx->var1 += ctx->var2;
134 	return 0;
135 }
136 
137 static int erst_exec_subtract(struct apei_exec_context *ctx,
138 			      struct acpi_whea_header *entry)
139 {
140 	ctx->var1 -= ctx->var2;
141 	return 0;
142 }
143 
144 static int erst_exec_add_value(struct apei_exec_context *ctx,
145 			       struct acpi_whea_header *entry)
146 {
147 	int rc;
148 	u64 val;
149 
150 	rc = __apei_exec_read_register(entry, &val);
151 	if (rc)
152 		return rc;
153 	val += ctx->value;
154 	rc = __apei_exec_write_register(entry, val);
155 	return rc;
156 }
157 
158 static int erst_exec_subtract_value(struct apei_exec_context *ctx,
159 				    struct acpi_whea_header *entry)
160 {
161 	int rc;
162 	u64 val;
163 
164 	rc = __apei_exec_read_register(entry, &val);
165 	if (rc)
166 		return rc;
167 	val -= ctx->value;
168 	rc = __apei_exec_write_register(entry, val);
169 	return rc;
170 }
171 
172 static int erst_exec_stall(struct apei_exec_context *ctx,
173 			   struct acpi_whea_header *entry)
174 {
175 	u64 stall_time;
176 
177 	if (ctx->value > FIRMWARE_MAX_STALL) {
178 		if (!in_nmi())
179 			pr_warn(FW_WARN
180 			"Too long stall time for stall instruction: 0x%llx.\n",
181 				   ctx->value);
182 		stall_time = FIRMWARE_MAX_STALL;
183 	} else
184 		stall_time = ctx->value;
185 	udelay(stall_time);
186 	return 0;
187 }
188 
189 static int erst_exec_stall_while_true(struct apei_exec_context *ctx,
190 				      struct acpi_whea_header *entry)
191 {
192 	int rc;
193 	u64 val;
194 	u64 timeout = FIRMWARE_TIMEOUT;
195 	u64 stall_time;
196 
197 	if (ctx->var1 > FIRMWARE_MAX_STALL) {
198 		if (!in_nmi())
199 			pr_warn(FW_WARN
200 		"Too long stall time for stall while true instruction: 0x%llx.\n",
201 				   ctx->var1);
202 		stall_time = FIRMWARE_MAX_STALL;
203 	} else
204 		stall_time = ctx->var1;
205 
206 	for (;;) {
207 		rc = __apei_exec_read_register(entry, &val);
208 		if (rc)
209 			return rc;
210 		if (val != ctx->value)
211 			break;
212 		if (erst_timedout(&timeout, stall_time * NSEC_PER_USEC))
213 			return -EIO;
214 	}
215 	return 0;
216 }
217 
218 static int erst_exec_skip_next_instruction_if_true(
219 	struct apei_exec_context *ctx,
220 	struct acpi_whea_header *entry)
221 {
222 	int rc;
223 	u64 val;
224 
225 	rc = __apei_exec_read_register(entry, &val);
226 	if (rc)
227 		return rc;
228 	if (val == ctx->value) {
229 		ctx->ip += 2;
230 		return APEI_EXEC_SET_IP;
231 	}
232 
233 	return 0;
234 }
235 
236 static int erst_exec_goto(struct apei_exec_context *ctx,
237 			  struct acpi_whea_header *entry)
238 {
239 	ctx->ip = ctx->value;
240 	return APEI_EXEC_SET_IP;
241 }
242 
243 static int erst_exec_set_src_address_base(struct apei_exec_context *ctx,
244 					  struct acpi_whea_header *entry)
245 {
246 	return __apei_exec_read_register(entry, &ctx->src_base);
247 }
248 
249 static int erst_exec_set_dst_address_base(struct apei_exec_context *ctx,
250 					  struct acpi_whea_header *entry)
251 {
252 	return __apei_exec_read_register(entry, &ctx->dst_base);
253 }
254 
255 static int erst_exec_move_data(struct apei_exec_context *ctx,
256 			       struct acpi_whea_header *entry)
257 {
258 	int rc;
259 	u64 offset;
260 	void *src, *dst;
261 
262 	/* ioremap does not work in interrupt context */
263 	if (in_interrupt()) {
264 		pr_warn("MOVE_DATA can not be used in interrupt context.\n");
265 		return -EBUSY;
266 	}
267 
268 	rc = __apei_exec_read_register(entry, &offset);
269 	if (rc)
270 		return rc;
271 
272 	src = ioremap(ctx->src_base + offset, ctx->var2);
273 	if (!src)
274 		return -ENOMEM;
275 	dst = ioremap(ctx->dst_base + offset, ctx->var2);
276 	if (!dst) {
277 		iounmap(src);
278 		return -ENOMEM;
279 	}
280 
281 	memmove(dst, src, ctx->var2);
282 
283 	iounmap(src);
284 	iounmap(dst);
285 
286 	return 0;
287 }
288 
289 static struct apei_exec_ins_type erst_ins_type[] = {
290 	[ACPI_ERST_READ_REGISTER] = {
291 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
292 		.run = apei_exec_read_register,
293 	},
294 	[ACPI_ERST_READ_REGISTER_VALUE] = {
295 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
296 		.run = apei_exec_read_register_value,
297 	},
298 	[ACPI_ERST_WRITE_REGISTER] = {
299 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
300 		.run = apei_exec_write_register,
301 	},
302 	[ACPI_ERST_WRITE_REGISTER_VALUE] = {
303 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
304 		.run = apei_exec_write_register_value,
305 	},
306 	[ACPI_ERST_NOOP] = {
307 		.flags = 0,
308 		.run = apei_exec_noop,
309 	},
310 	[ACPI_ERST_LOAD_VAR1] = {
311 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
312 		.run = erst_exec_load_var1,
313 	},
314 	[ACPI_ERST_LOAD_VAR2] = {
315 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
316 		.run = erst_exec_load_var2,
317 	},
318 	[ACPI_ERST_STORE_VAR1] = {
319 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
320 		.run = erst_exec_store_var1,
321 	},
322 	[ACPI_ERST_ADD] = {
323 		.flags = 0,
324 		.run = erst_exec_add,
325 	},
326 	[ACPI_ERST_SUBTRACT] = {
327 		.flags = 0,
328 		.run = erst_exec_subtract,
329 	},
330 	[ACPI_ERST_ADD_VALUE] = {
331 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
332 		.run = erst_exec_add_value,
333 	},
334 	[ACPI_ERST_SUBTRACT_VALUE] = {
335 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
336 		.run = erst_exec_subtract_value,
337 	},
338 	[ACPI_ERST_STALL] = {
339 		.flags = 0,
340 		.run = erst_exec_stall,
341 	},
342 	[ACPI_ERST_STALL_WHILE_TRUE] = {
343 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
344 		.run = erst_exec_stall_while_true,
345 	},
346 	[ACPI_ERST_SKIP_NEXT_IF_TRUE] = {
347 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
348 		.run = erst_exec_skip_next_instruction_if_true,
349 	},
350 	[ACPI_ERST_GOTO] = {
351 		.flags = 0,
352 		.run = erst_exec_goto,
353 	},
354 	[ACPI_ERST_SET_SRC_ADDRESS_BASE] = {
355 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
356 		.run = erst_exec_set_src_address_base,
357 	},
358 	[ACPI_ERST_SET_DST_ADDRESS_BASE] = {
359 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
360 		.run = erst_exec_set_dst_address_base,
361 	},
362 	[ACPI_ERST_MOVE_DATA] = {
363 		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
364 		.run = erst_exec_move_data,
365 	},
366 };
367 
368 static inline void erst_exec_ctx_init(struct apei_exec_context *ctx)
369 {
370 	apei_exec_ctx_init(ctx, erst_ins_type, ARRAY_SIZE(erst_ins_type),
371 			   ERST_TAB_ENTRY(erst_tab), erst_tab->entries);
372 }
373 
374 static int erst_get_erange(struct erst_erange *range)
375 {
376 	struct apei_exec_context ctx;
377 	int rc;
378 
379 	erst_exec_ctx_init(&ctx);
380 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_RANGE);
381 	if (rc)
382 		return rc;
383 	range->base = apei_exec_ctx_get_output(&ctx);
384 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_LENGTH);
385 	if (rc)
386 		return rc;
387 	range->size = apei_exec_ctx_get_output(&ctx);
388 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_ATTRIBUTES);
389 	if (rc)
390 		return rc;
391 	range->attr = apei_exec_ctx_get_output(&ctx);
392 
393 	return 0;
394 }
395 
396 static ssize_t __erst_get_record_count(void)
397 {
398 	struct apei_exec_context ctx;
399 	int rc;
400 
401 	erst_exec_ctx_init(&ctx);
402 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_COUNT);
403 	if (rc)
404 		return rc;
405 	return apei_exec_ctx_get_output(&ctx);
406 }
407 
408 ssize_t erst_get_record_count(void)
409 {
410 	ssize_t count;
411 	unsigned long flags;
412 
413 	if (erst_disable)
414 		return -ENODEV;
415 
416 	raw_spin_lock_irqsave(&erst_lock, flags);
417 	count = __erst_get_record_count();
418 	raw_spin_unlock_irqrestore(&erst_lock, flags);
419 
420 	return count;
421 }
422 EXPORT_SYMBOL_GPL(erst_get_record_count);
423 
424 #define ERST_RECORD_ID_CACHE_SIZE_MIN	16
425 #define ERST_RECORD_ID_CACHE_SIZE_MAX	1024
426 
427 struct erst_record_id_cache {
428 	struct mutex lock;
429 	u64 *entries;
430 	int len;
431 	int size;
432 	int refcount;
433 };
434 
435 static struct erst_record_id_cache erst_record_id_cache = {
436 	.lock = __MUTEX_INITIALIZER(erst_record_id_cache.lock),
437 	.refcount = 0,
438 };
439 
440 static int __erst_get_next_record_id(u64 *record_id)
441 {
442 	struct apei_exec_context ctx;
443 	int rc;
444 
445 	erst_exec_ctx_init(&ctx);
446 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_ID);
447 	if (rc)
448 		return rc;
449 	*record_id = apei_exec_ctx_get_output(&ctx);
450 
451 	return 0;
452 }
453 
454 int erst_get_record_id_begin(int *pos)
455 {
456 	int rc;
457 
458 	if (erst_disable)
459 		return -ENODEV;
460 
461 	rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
462 	if (rc)
463 		return rc;
464 	erst_record_id_cache.refcount++;
465 	mutex_unlock(&erst_record_id_cache.lock);
466 
467 	*pos = 0;
468 
469 	return 0;
470 }
471 EXPORT_SYMBOL_GPL(erst_get_record_id_begin);
472 
473 /* erst_record_id_cache.lock must be held by caller */
474 static int __erst_record_id_cache_add_one(void)
475 {
476 	u64 id, prev_id, first_id;
477 	int i, rc;
478 	u64 *entries;
479 	unsigned long flags;
480 
481 	id = prev_id = first_id = APEI_ERST_INVALID_RECORD_ID;
482 retry:
483 	raw_spin_lock_irqsave(&erst_lock, flags);
484 	rc = __erst_get_next_record_id(&id);
485 	raw_spin_unlock_irqrestore(&erst_lock, flags);
486 	if (rc == -ENOENT)
487 		return 0;
488 	if (rc)
489 		return rc;
490 	if (id == APEI_ERST_INVALID_RECORD_ID)
491 		return 0;
492 	/* can not skip current ID, or loop back to first ID */
493 	if (id == prev_id || id == first_id)
494 		return 0;
495 	if (first_id == APEI_ERST_INVALID_RECORD_ID)
496 		first_id = id;
497 	prev_id = id;
498 
499 	entries = erst_record_id_cache.entries;
500 	for (i = 0; i < erst_record_id_cache.len; i++) {
501 		if (entries[i] == id)
502 			break;
503 	}
504 	/* record id already in cache, try next */
505 	if (i < erst_record_id_cache.len)
506 		goto retry;
507 	if (erst_record_id_cache.len >= erst_record_id_cache.size) {
508 		int new_size;
509 		u64 *new_entries;
510 
511 		new_size = erst_record_id_cache.size * 2;
512 		new_size = clamp_val(new_size, ERST_RECORD_ID_CACHE_SIZE_MIN,
513 				     ERST_RECORD_ID_CACHE_SIZE_MAX);
514 		if (new_size <= erst_record_id_cache.size) {
515 			if (printk_ratelimit())
516 				pr_warn(FW_WARN "too many record IDs!\n");
517 			return 0;
518 		}
519 		new_entries = kvmalloc_array(new_size, sizeof(entries[0]),
520 					     GFP_KERNEL);
521 		if (!new_entries)
522 			return -ENOMEM;
523 		memcpy(new_entries, entries,
524 		       erst_record_id_cache.len * sizeof(entries[0]));
525 		kvfree(entries);
526 		erst_record_id_cache.entries = entries = new_entries;
527 		erst_record_id_cache.size = new_size;
528 	}
529 	entries[i] = id;
530 	erst_record_id_cache.len++;
531 
532 	return 1;
533 }
534 
535 /*
536  * Get the record ID of an existing error record on the persistent
537  * storage. If there is no error record on the persistent storage, the
538  * returned record_id is APEI_ERST_INVALID_RECORD_ID.
539  */
540 int erst_get_record_id_next(int *pos, u64 *record_id)
541 {
542 	int rc = 0;
543 	u64 *entries;
544 
545 	if (erst_disable)
546 		return -ENODEV;
547 
548 	/* must be enclosed by erst_get_record_id_begin/end */
549 	BUG_ON(!erst_record_id_cache.refcount);
550 	BUG_ON(*pos < 0 || *pos > erst_record_id_cache.len);
551 
552 	mutex_lock(&erst_record_id_cache.lock);
553 	entries = erst_record_id_cache.entries;
554 	for (; *pos < erst_record_id_cache.len; (*pos)++)
555 		if (entries[*pos] != APEI_ERST_INVALID_RECORD_ID)
556 			break;
557 	/* found next record id in cache */
558 	if (*pos < erst_record_id_cache.len) {
559 		*record_id = entries[*pos];
560 		(*pos)++;
561 		goto out_unlock;
562 	}
563 
564 	/* Try to add one more record ID to cache */
565 	rc = __erst_record_id_cache_add_one();
566 	if (rc < 0)
567 		goto out_unlock;
568 	/* successfully add one new ID */
569 	if (rc == 1) {
570 		*record_id = erst_record_id_cache.entries[*pos];
571 		(*pos)++;
572 		rc = 0;
573 	} else {
574 		*pos = -1;
575 		*record_id = APEI_ERST_INVALID_RECORD_ID;
576 	}
577 out_unlock:
578 	mutex_unlock(&erst_record_id_cache.lock);
579 
580 	return rc;
581 }
582 EXPORT_SYMBOL_GPL(erst_get_record_id_next);
583 
584 /* erst_record_id_cache.lock must be held by caller */
585 static void __erst_record_id_cache_compact(void)
586 {
587 	int i, wpos = 0;
588 	u64 *entries;
589 
590 	if (erst_record_id_cache.refcount)
591 		return;
592 
593 	entries = erst_record_id_cache.entries;
594 	for (i = 0; i < erst_record_id_cache.len; i++) {
595 		if (entries[i] == APEI_ERST_INVALID_RECORD_ID)
596 			continue;
597 		if (wpos != i)
598 			entries[wpos] = entries[i];
599 		wpos++;
600 	}
601 	erst_record_id_cache.len = wpos;
602 }
603 
604 void erst_get_record_id_end(void)
605 {
606 	/*
607 	 * erst_disable != 0 should be detected by invoker via the
608 	 * return value of erst_get_record_id_begin/next, so this
609 	 * function should not be called for erst_disable != 0.
610 	 */
611 	BUG_ON(erst_disable);
612 
613 	mutex_lock(&erst_record_id_cache.lock);
614 	erst_record_id_cache.refcount--;
615 	BUG_ON(erst_record_id_cache.refcount < 0);
616 	__erst_record_id_cache_compact();
617 	mutex_unlock(&erst_record_id_cache.lock);
618 }
619 EXPORT_SYMBOL_GPL(erst_get_record_id_end);
620 
621 static int __erst_write_to_storage(u64 offset)
622 {
623 	struct apei_exec_context ctx;
624 	u64 timeout = FIRMWARE_TIMEOUT;
625 	u64 val;
626 	int rc;
627 
628 	erst_exec_ctx_init(&ctx);
629 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_WRITE);
630 	if (rc)
631 		return rc;
632 	apei_exec_ctx_set_input(&ctx, offset);
633 	rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
634 	if (rc)
635 		return rc;
636 	rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
637 	if (rc)
638 		return rc;
639 	for (;;) {
640 		rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
641 		if (rc)
642 			return rc;
643 		val = apei_exec_ctx_get_output(&ctx);
644 		if (!val)
645 			break;
646 		if (erst_timedout(&timeout, SPIN_UNIT))
647 			return -EIO;
648 	}
649 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
650 	if (rc)
651 		return rc;
652 	val = apei_exec_ctx_get_output(&ctx);
653 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
654 	if (rc)
655 		return rc;
656 
657 	return erst_errno(val);
658 }
659 
660 static int __erst_read_from_storage(u64 record_id, u64 offset)
661 {
662 	struct apei_exec_context ctx;
663 	u64 timeout = FIRMWARE_TIMEOUT;
664 	u64 val;
665 	int rc;
666 
667 	erst_exec_ctx_init(&ctx);
668 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_READ);
669 	if (rc)
670 		return rc;
671 	apei_exec_ctx_set_input(&ctx, offset);
672 	rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
673 	if (rc)
674 		return rc;
675 	apei_exec_ctx_set_input(&ctx, record_id);
676 	rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
677 	if (rc)
678 		return rc;
679 	rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
680 	if (rc)
681 		return rc;
682 	for (;;) {
683 		rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
684 		if (rc)
685 			return rc;
686 		val = apei_exec_ctx_get_output(&ctx);
687 		if (!val)
688 			break;
689 		if (erst_timedout(&timeout, SPIN_UNIT))
690 			return -EIO;
691 	}
692 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
693 	if (rc)
694 		return rc;
695 	val = apei_exec_ctx_get_output(&ctx);
696 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
697 	if (rc)
698 		return rc;
699 
700 	return erst_errno(val);
701 }
702 
703 static int __erst_clear_from_storage(u64 record_id)
704 {
705 	struct apei_exec_context ctx;
706 	u64 timeout = FIRMWARE_TIMEOUT;
707 	u64 val;
708 	int rc;
709 
710 	erst_exec_ctx_init(&ctx);
711 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_BEGIN_CLEAR);
712 	if (rc)
713 		return rc;
714 	apei_exec_ctx_set_input(&ctx, record_id);
715 	rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
716 	if (rc)
717 		return rc;
718 	rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
719 	if (rc)
720 		return rc;
721 	for (;;) {
722 		rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
723 		if (rc)
724 			return rc;
725 		val = apei_exec_ctx_get_output(&ctx);
726 		if (!val)
727 			break;
728 		if (erst_timedout(&timeout, SPIN_UNIT))
729 			return -EIO;
730 	}
731 	rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
732 	if (rc)
733 		return rc;
734 	val = apei_exec_ctx_get_output(&ctx);
735 	rc = apei_exec_run_optional(&ctx, ACPI_ERST_END);
736 	if (rc)
737 		return rc;
738 
739 	return erst_errno(val);
740 }
741 
742 /* NVRAM ERST Error Log Address Range is not supported yet */
743 static void pr_unimpl_nvram(void)
744 {
745 	if (printk_ratelimit())
746 		pr_warn("NVRAM ERST Log Address Range not implemented yet.\n");
747 }
748 
749 static int __erst_write_to_nvram(const struct cper_record_header *record)
750 {
751 	/* do not print message, because printk is not safe for NMI */
752 	return -ENOSYS;
753 }
754 
755 static int __erst_read_to_erange_from_nvram(u64 record_id, u64 *offset)
756 {
757 	pr_unimpl_nvram();
758 	return -ENOSYS;
759 }
760 
761 static int __erst_clear_from_nvram(u64 record_id)
762 {
763 	pr_unimpl_nvram();
764 	return -ENOSYS;
765 }
766 
767 int erst_write(const struct cper_record_header *record)
768 {
769 	int rc;
770 	unsigned long flags;
771 	struct cper_record_header *rcd_erange;
772 
773 	if (erst_disable)
774 		return -ENODEV;
775 
776 	if (memcmp(record->signature, CPER_SIG_RECORD, CPER_SIG_SIZE))
777 		return -EINVAL;
778 
779 	if (erst_erange.attr & ERST_RANGE_NVRAM) {
780 		if (!raw_spin_trylock_irqsave(&erst_lock, flags))
781 			return -EBUSY;
782 		rc = __erst_write_to_nvram(record);
783 		raw_spin_unlock_irqrestore(&erst_lock, flags);
784 		return rc;
785 	}
786 
787 	if (record->record_length > erst_erange.size)
788 		return -EINVAL;
789 
790 	if (!raw_spin_trylock_irqsave(&erst_lock, flags))
791 		return -EBUSY;
792 	memcpy(erst_erange.vaddr, record, record->record_length);
793 	rcd_erange = erst_erange.vaddr;
794 	/* signature for serialization system */
795 	memcpy(&rcd_erange->persistence_information, "ER", 2);
796 
797 	rc = __erst_write_to_storage(0);
798 	raw_spin_unlock_irqrestore(&erst_lock, flags);
799 
800 	return rc;
801 }
802 EXPORT_SYMBOL_GPL(erst_write);
803 
804 static int __erst_read_to_erange(u64 record_id, u64 *offset)
805 {
806 	int rc;
807 
808 	if (erst_erange.attr & ERST_RANGE_NVRAM)
809 		return __erst_read_to_erange_from_nvram(
810 			record_id, offset);
811 
812 	rc = __erst_read_from_storage(record_id, 0);
813 	if (rc)
814 		return rc;
815 	*offset = 0;
816 
817 	return 0;
818 }
819 
820 static ssize_t __erst_read(u64 record_id, struct cper_record_header *record,
821 			   size_t buflen)
822 {
823 	int rc;
824 	u64 offset, len = 0;
825 	struct cper_record_header *rcd_tmp;
826 
827 	rc = __erst_read_to_erange(record_id, &offset);
828 	if (rc)
829 		return rc;
830 	rcd_tmp = erst_erange.vaddr + offset;
831 	len = rcd_tmp->record_length;
832 	if (len <= buflen)
833 		memcpy(record, rcd_tmp, len);
834 
835 	return len;
836 }
837 
838 /*
839  * If return value > buflen, the buffer size is not big enough,
840  * else if return value < 0, something goes wrong,
841  * else everything is OK, and return value is record length
842  */
843 ssize_t erst_read(u64 record_id, struct cper_record_header *record,
844 		  size_t buflen)
845 {
846 	ssize_t len;
847 	unsigned long flags;
848 
849 	if (erst_disable)
850 		return -ENODEV;
851 
852 	raw_spin_lock_irqsave(&erst_lock, flags);
853 	len = __erst_read(record_id, record, buflen);
854 	raw_spin_unlock_irqrestore(&erst_lock, flags);
855 	return len;
856 }
857 EXPORT_SYMBOL_GPL(erst_read);
858 
859 int erst_clear(u64 record_id)
860 {
861 	int rc, i;
862 	unsigned long flags;
863 	u64 *entries;
864 
865 	if (erst_disable)
866 		return -ENODEV;
867 
868 	rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
869 	if (rc)
870 		return rc;
871 	raw_spin_lock_irqsave(&erst_lock, flags);
872 	if (erst_erange.attr & ERST_RANGE_NVRAM)
873 		rc = __erst_clear_from_nvram(record_id);
874 	else
875 		rc = __erst_clear_from_storage(record_id);
876 	raw_spin_unlock_irqrestore(&erst_lock, flags);
877 	if (rc)
878 		goto out;
879 	entries = erst_record_id_cache.entries;
880 	for (i = 0; i < erst_record_id_cache.len; i++) {
881 		if (entries[i] == record_id)
882 			entries[i] = APEI_ERST_INVALID_RECORD_ID;
883 	}
884 	__erst_record_id_cache_compact();
885 out:
886 	mutex_unlock(&erst_record_id_cache.lock);
887 	return rc;
888 }
889 EXPORT_SYMBOL_GPL(erst_clear);
890 
891 static int __init setup_erst_disable(char *str)
892 {
893 	erst_disable = 1;
894 	return 1;
895 }
896 
897 __setup("erst_disable", setup_erst_disable);
898 
899 static int erst_check_table(struct acpi_table_erst *erst_tab)
900 {
901 	if ((erst_tab->header_length !=
902 	     (sizeof(struct acpi_table_erst) - sizeof(erst_tab->header)))
903 	    && (erst_tab->header_length != sizeof(struct acpi_table_erst)))
904 		return -EINVAL;
905 	if (erst_tab->header.length < sizeof(struct acpi_table_erst))
906 		return -EINVAL;
907 	if (erst_tab->entries !=
908 	    (erst_tab->header.length - sizeof(struct acpi_table_erst)) /
909 	    sizeof(struct acpi_erst_entry))
910 		return -EINVAL;
911 
912 	return 0;
913 }
914 
915 static int erst_open_pstore(struct pstore_info *psi);
916 static int erst_close_pstore(struct pstore_info *psi);
917 static ssize_t erst_reader(struct pstore_record *record);
918 static int erst_writer(struct pstore_record *record);
919 static int erst_clearer(struct pstore_record *record);
920 
921 static struct pstore_info erst_info = {
922 	.owner		= THIS_MODULE,
923 	.name		= "erst",
924 	.flags		= PSTORE_FLAGS_DMESG,
925 	.open		= erst_open_pstore,
926 	.close		= erst_close_pstore,
927 	.read		= erst_reader,
928 	.write		= erst_writer,
929 	.erase		= erst_clearer
930 };
931 
932 #define CPER_CREATOR_PSTORE						\
933 	GUID_INIT(0x75a574e3, 0x5052, 0x4b29, 0x8a, 0x8e, 0xbe, 0x2c,	\
934 		  0x64, 0x90, 0xb8, 0x9d)
935 #define CPER_SECTION_TYPE_DMESG						\
936 	GUID_INIT(0xc197e04e, 0xd545, 0x4a70, 0x9c, 0x17, 0xa5, 0x54,	\
937 		  0x94, 0x19, 0xeb, 0x12)
938 #define CPER_SECTION_TYPE_DMESG_Z					\
939 	GUID_INIT(0x4f118707, 0x04dd, 0x4055, 0xb5, 0xdd, 0x95, 0x6d,	\
940 		  0x34, 0xdd, 0xfa, 0xc6)
941 #define CPER_SECTION_TYPE_MCE						\
942 	GUID_INIT(0xfe08ffbe, 0x95e4, 0x4be7, 0xbc, 0x73, 0x40, 0x96,	\
943 		  0x04, 0x4a, 0x38, 0xfc)
944 
945 struct cper_pstore_record {
946 	struct cper_record_header hdr;
947 	struct cper_section_descriptor sec_hdr;
948 	char data[];
949 } __packed;
950 
951 static int reader_pos;
952 
953 static int erst_open_pstore(struct pstore_info *psi)
954 {
955 	int rc;
956 
957 	if (erst_disable)
958 		return -ENODEV;
959 
960 	rc = erst_get_record_id_begin(&reader_pos);
961 
962 	return rc;
963 }
964 
965 static int erst_close_pstore(struct pstore_info *psi)
966 {
967 	erst_get_record_id_end();
968 
969 	return 0;
970 }
971 
972 static ssize_t erst_reader(struct pstore_record *record)
973 {
974 	int rc;
975 	ssize_t len = 0;
976 	u64 record_id;
977 	struct cper_pstore_record *rcd;
978 	size_t rcd_len = sizeof(*rcd) + erst_info.bufsize;
979 
980 	if (erst_disable)
981 		return -ENODEV;
982 
983 	rcd = kmalloc(rcd_len, GFP_KERNEL);
984 	if (!rcd) {
985 		rc = -ENOMEM;
986 		goto out;
987 	}
988 skip:
989 	rc = erst_get_record_id_next(&reader_pos, &record_id);
990 	if (rc)
991 		goto out;
992 
993 	/* no more record */
994 	if (record_id == APEI_ERST_INVALID_RECORD_ID) {
995 		rc = -EINVAL;
996 		goto out;
997 	}
998 
999 	len = erst_read(record_id, &rcd->hdr, rcd_len);
1000 	/* The record may be cleared by others, try read next record */
1001 	if (len == -ENOENT)
1002 		goto skip;
1003 	else if (len < 0 || len < sizeof(*rcd)) {
1004 		rc = -EIO;
1005 		goto out;
1006 	}
1007 	if (!guid_equal(&rcd->hdr.creator_id, &CPER_CREATOR_PSTORE))
1008 		goto skip;
1009 
1010 	record->buf = kmalloc(len, GFP_KERNEL);
1011 	if (record->buf == NULL) {
1012 		rc = -ENOMEM;
1013 		goto out;
1014 	}
1015 	memcpy(record->buf, rcd->data, len - sizeof(*rcd));
1016 	record->id = record_id;
1017 	record->compressed = false;
1018 	record->ecc_notice_size = 0;
1019 	if (guid_equal(&rcd->sec_hdr.section_type, &CPER_SECTION_TYPE_DMESG_Z)) {
1020 		record->type = PSTORE_TYPE_DMESG;
1021 		record->compressed = true;
1022 	} else if (guid_equal(&rcd->sec_hdr.section_type, &CPER_SECTION_TYPE_DMESG))
1023 		record->type = PSTORE_TYPE_DMESG;
1024 	else if (guid_equal(&rcd->sec_hdr.section_type, &CPER_SECTION_TYPE_MCE))
1025 		record->type = PSTORE_TYPE_MCE;
1026 	else
1027 		record->type = PSTORE_TYPE_MAX;
1028 
1029 	if (rcd->hdr.validation_bits & CPER_VALID_TIMESTAMP)
1030 		record->time.tv_sec = rcd->hdr.timestamp;
1031 	else
1032 		record->time.tv_sec = 0;
1033 	record->time.tv_nsec = 0;
1034 
1035 out:
1036 	kfree(rcd);
1037 	return (rc < 0) ? rc : (len - sizeof(*rcd));
1038 }
1039 
1040 static int erst_writer(struct pstore_record *record)
1041 {
1042 	struct cper_pstore_record *rcd = (struct cper_pstore_record *)
1043 					(erst_info.buf - sizeof(*rcd));
1044 	int ret;
1045 
1046 	memset(rcd, 0, sizeof(*rcd));
1047 	memcpy(rcd->hdr.signature, CPER_SIG_RECORD, CPER_SIG_SIZE);
1048 	rcd->hdr.revision = CPER_RECORD_REV;
1049 	rcd->hdr.signature_end = CPER_SIG_END;
1050 	rcd->hdr.section_count = 1;
1051 	rcd->hdr.error_severity = CPER_SEV_FATAL;
1052 	/* timestamp valid. platform_id, partition_id are invalid */
1053 	rcd->hdr.validation_bits = CPER_VALID_TIMESTAMP;
1054 	rcd->hdr.timestamp = ktime_get_real_seconds();
1055 	rcd->hdr.record_length = sizeof(*rcd) + record->size;
1056 	rcd->hdr.creator_id = CPER_CREATOR_PSTORE;
1057 	rcd->hdr.notification_type = CPER_NOTIFY_MCE;
1058 	rcd->hdr.record_id = cper_next_record_id();
1059 	rcd->hdr.flags = CPER_HW_ERROR_FLAGS_PREVERR;
1060 
1061 	rcd->sec_hdr.section_offset = sizeof(*rcd);
1062 	rcd->sec_hdr.section_length = record->size;
1063 	rcd->sec_hdr.revision = CPER_SEC_REV;
1064 	/* fru_id and fru_text is invalid */
1065 	rcd->sec_hdr.validation_bits = 0;
1066 	rcd->sec_hdr.flags = CPER_SEC_PRIMARY;
1067 	switch (record->type) {
1068 	case PSTORE_TYPE_DMESG:
1069 		if (record->compressed)
1070 			rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG_Z;
1071 		else
1072 			rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG;
1073 		break;
1074 	case PSTORE_TYPE_MCE:
1075 		rcd->sec_hdr.section_type = CPER_SECTION_TYPE_MCE;
1076 		break;
1077 	default:
1078 		return -EINVAL;
1079 	}
1080 	rcd->sec_hdr.section_severity = CPER_SEV_FATAL;
1081 
1082 	ret = erst_write(&rcd->hdr);
1083 	record->id = rcd->hdr.record_id;
1084 
1085 	return ret;
1086 }
1087 
1088 static int erst_clearer(struct pstore_record *record)
1089 {
1090 	return erst_clear(record->id);
1091 }
1092 
1093 static int __init erst_init(void)
1094 {
1095 	int rc = 0;
1096 	acpi_status status;
1097 	struct apei_exec_context ctx;
1098 	struct apei_resources erst_resources;
1099 	struct resource *r;
1100 	char *buf;
1101 
1102 	if (acpi_disabled)
1103 		goto err;
1104 
1105 	if (erst_disable) {
1106 		pr_info(
1107 	"Error Record Serialization Table (ERST) support is disabled.\n");
1108 		goto err;
1109 	}
1110 
1111 	status = acpi_get_table(ACPI_SIG_ERST, 0,
1112 				(struct acpi_table_header **)&erst_tab);
1113 	if (status == AE_NOT_FOUND)
1114 		goto err;
1115 	else if (ACPI_FAILURE(status)) {
1116 		const char *msg = acpi_format_exception(status);
1117 		pr_err("Failed to get table, %s\n", msg);
1118 		rc = -EINVAL;
1119 		goto err;
1120 	}
1121 
1122 	rc = erst_check_table(erst_tab);
1123 	if (rc) {
1124 		pr_err(FW_BUG "ERST table is invalid.\n");
1125 		goto err_put_erst_tab;
1126 	}
1127 
1128 	apei_resources_init(&erst_resources);
1129 	erst_exec_ctx_init(&ctx);
1130 	rc = apei_exec_collect_resources(&ctx, &erst_resources);
1131 	if (rc)
1132 		goto err_fini;
1133 	rc = apei_resources_request(&erst_resources, "APEI ERST");
1134 	if (rc)
1135 		goto err_fini;
1136 	rc = apei_exec_pre_map_gars(&ctx);
1137 	if (rc)
1138 		goto err_release;
1139 	rc = erst_get_erange(&erst_erange);
1140 	if (rc) {
1141 		if (rc == -ENODEV)
1142 			pr_info(
1143 	"The corresponding hardware device or firmware implementation "
1144 	"is not available.\n");
1145 		else
1146 			pr_err("Failed to get Error Log Address Range.\n");
1147 		goto err_unmap_reg;
1148 	}
1149 
1150 	r = request_mem_region(erst_erange.base, erst_erange.size, "APEI ERST");
1151 	if (!r) {
1152 		pr_err("Can not request [mem %#010llx-%#010llx] for ERST.\n",
1153 		       (unsigned long long)erst_erange.base,
1154 		       (unsigned long long)erst_erange.base + erst_erange.size - 1);
1155 		rc = -EIO;
1156 		goto err_unmap_reg;
1157 	}
1158 	rc = -ENOMEM;
1159 	erst_erange.vaddr = ioremap_cache(erst_erange.base,
1160 					  erst_erange.size);
1161 	if (!erst_erange.vaddr)
1162 		goto err_release_erange;
1163 
1164 	pr_info(
1165 	"Error Record Serialization Table (ERST) support is initialized.\n");
1166 
1167 	buf = kmalloc(erst_erange.size, GFP_KERNEL);
1168 	if (buf) {
1169 		erst_info.buf = buf + sizeof(struct cper_pstore_record);
1170 		erst_info.bufsize = erst_erange.size -
1171 				    sizeof(struct cper_pstore_record);
1172 		rc = pstore_register(&erst_info);
1173 		if (rc) {
1174 			if (rc != -EPERM)
1175 				pr_info(
1176 				"Could not register with persistent store.\n");
1177 			erst_info.buf = NULL;
1178 			erst_info.bufsize = 0;
1179 			kfree(buf);
1180 		}
1181 	} else
1182 		pr_err(
1183 		"Failed to allocate %lld bytes for persistent store error log.\n",
1184 		erst_erange.size);
1185 
1186 	/* Cleanup ERST Resources */
1187 	apei_resources_fini(&erst_resources);
1188 
1189 	return 0;
1190 
1191 err_release_erange:
1192 	release_mem_region(erst_erange.base, erst_erange.size);
1193 err_unmap_reg:
1194 	apei_exec_post_unmap_gars(&ctx);
1195 err_release:
1196 	apei_resources_release(&erst_resources);
1197 err_fini:
1198 	apei_resources_fini(&erst_resources);
1199 err_put_erst_tab:
1200 	acpi_put_table((struct acpi_table_header *)erst_tab);
1201 err:
1202 	erst_disable = 1;
1203 	return rc;
1204 }
1205 
1206 device_initcall(erst_init);
1207